Glomerular Disease Update for the Clinician:

Anti-glomerular Basement Membrane Disease

Stephen P. McAdoo & Charles D. Pusey

Renal and Vascular Inflammation Section, Department of Medicine, Imperial College London

Corresponding Author: Stephen P. McAdoo, Renal and Vascular Inflammation Section, Department

of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12

0NN; e-mail: s.mcadoo@imperial.ac.uk; telephone: +44 208 383 3152; fax: +44 208 383 2062.

Word Count: 4900 (excluding abstract, figures, tables, legends and references)

Abstract: 270

Tables: 1

Figures: 3

References: 102

Running Title: Anti-GBM disease

Abstract

Anti-glomerular basement membrane (GBM) disease is a rare small vessel vasculitis that affects the

capillary beds of the kidneys and lungs. It is an archetypical autoimmune disease, caused by the

development of directly pathogenic autoantibodies targeting a well-characterised autoantigen

expressed in the basement membranes of these organs, although the inciting events that induce the

autoimmune response are not fully understood. The recent confirmation of spatial and temporal

clustering of cases suggest that environmental factors, including infection, may trigger disease in

genetically susceptible individuals. The majority of patients develop widespread glomerular crescent

formation, presenting with features of rapidly progressive glomerulonephritis, and 40-60% will have

concurrent alveolar haemorrhage. Treatment aims to rapidly remove pathogenic autoantibody,

typically with the use of plasma exchange, along with steroids and cytotoxic therapy to prevent

ongoing autoantibody production and tissue inflammation. Retrospective cohort studies suggest that

when this combination of treatment is started early, the majority of patients will have good renal

outcome, though presentation with oligoanuria, a high proportion of glomerular crescents, or kidney

failure requiring dialysis augur badly for renal prognosis. Relapse and recurrent disease after kidney

transplantation are both uncommon, though de novo anti-GBM disease after transplantation for

Alport syndrome is a recognised phenomenon. Co-presentation with other kidney diseases such as

ANCA-associated vasculitis and membranous nephropathy seems to occur at a higher frequency

than would be expected by chance alone, and in addition atypical presentations of anti-GBM disease

are increasingly reported. These observations highlight the need for future work to further delineate

the immunopathogenic mechanisms of anti-GBM disease, and how to better refine and improve

treatments, particularly for patients presenting with adverse prognostic factors.

Nomenclature and History

Anti-glomerular basement membrane (GBM) disease is a rare small vessel vasculitis that affects

glomerular capillaries (where it may result in glomerular necrosis and crescent formation),

pulmonary capillaries (where it may cause alveolar haemorrhage), or both. It is characterised by the

presence of circulating and deposited antibodies directed against basement membrane antigens,

and as such is classified an immune-complex small vessel vasculitis in the Revised International

Chapel Hill Consensus Conference Nomenclature of Vasculitides1. The Consensus acknowledges the

relative misnomer of anti-glomerular basement membrane disease, given the frequent involvement

of alveolar basement membranes, though recognises the widely accepted use of anti-GBM disease

to describe this condition with or without lung involvement.

The eponymous term ‘Goodpasture disease’ is also used to describe this condition, first being used

by Australians Stanton and Tange in 19582, in their report describing nine case of glomerulonephritis

(GN) associated with lung haemorrhage. They credited Ernest Goodpasture, an American

pathologist, with the first description of the syndrome in his 1919 paper describing a fatal case of GN

and lung haemorrhage that was, at the time, attributed to an atypical influenza infection 3. We do not

know, however, if any of these patients had anti-GBM disease as we recognise it today, since it was

not until the development of immunofluorescence techniques in the 1960s that it became possible

to detect anti-GBM antibodies in kidney tissue4, and to demonstrate their pathogenic potential upon

elution and transfer to non-human primates5. The detection of circulating anti-GBM antibodies in

patients quickly followed6, and the first comprehensive clinical description of ‘anti-GBM antibody-

induced GN’ was by Wilson and Dixon in 19737. It is of historical interest to note that Goodpasture’s

original description of lung and kidney disease in association with intestinal and splenic

inflammation, following a sub-acute clinical presentation, was perhaps more in keeping with a

diagnosis of ANCA-associated vasculitis (AAV) than anti-GBM disease, and that Goodpasture himself

is said to have rejected the eponymous use of his name.

The term ‘Goodpasture disease’ has persisted, however, being generally reserved for patients with

demonstrable anti-GBM antibodies, whereas ‘Goodpasture syndrome’ may be used to describe co-

presentation with GN and pulmonary haemorrhage of any cause. We will use the term ‘anti-GBM

GN’ when referring specifically to the kidney involvement seen in this condition, and ‘anti-GBM

disease’ when referring to the broader spectrum of kidney and lung disease.

Epidemiology and Aetiological Associations

Given its rarity, definitive observations regarding the incidence of anti-GBM disease are lacking. It is

often said to have an incidence of less than 1 pmp/yr in European populations, largely based on

single-centre biopsy- or serology-based series, though accurately defining populations at risk in such

studies is difficult. A recent study from Ireland is notable for being the first to define a nationwide

disease incidence, by identifying all cases over a decade via reference immunology laboratories and

a nationwide pathology database8. It reported a disease rate of 1.64 pmp/yr, higher than previous

estimates. The disease is well recognised in other Caucasian and in Asian populations9-12, though is

thought to be rarer in African populations13.

Anti-GBM GN accounts for 10-15% of all cases of crescentic glomerulonephritis in large biopsy

series14, though it appears to be a rare cause of end-stage kidney disease (ESKD) 15. A common

observation from larger series of anti-GBM disease is that of a bimodal age distribution, with peak

incidences in the 3rd decade, where a slight male preponderance and presentation with both kidney

and lung disease is observed, and in the 6-7th decades, where presentation with isolated kidney

disease is more common16-18.

Some series have reported disease ‘outbreaks’ and seasonal variation in incidence 16, 17, and the Irish

study identified spatial and temporal clustering of disease, suggesting that environmental factors

may be important triggers for disease onset, though they are yet to be accurately defined 8, 19.

Infectious associations, particularly with influenza A, have been the subject of anecdotal reports 20, 21,

and may account for the aforementioned seasonal or geographic ‘clustering’ of anti-GBM disease

cases, and a recent study described a high prevalence of prodromal upper and lower respiratory

tract infection in a cohort of 140 Chinese patients22. The causative nature of these associations,

however, is not proven and remains speculative.

A more conclusive environmental association is that with cigarette smoking and the development of

lung haemorrhage in anti-GBM disease23. Similarly, inhalation of hydrocarbons has also been

implicated in disease onset24. It is suggested that that localised inflammation induced by inhaled

toxins may increase capillary permeability, or potentially disrupt the quaternary structure of the

alveolar basement membrane, exposing usually sequestered antigens and allowing access to

pathogenic autoantibodies.

A more recently identified trigger for anti-GBM disease is treatment with the anti-CD52 monoclonal

antibody, alemtuzumab, a lymphocyte depleting agent that is increasingly used in the treatment of

relapsing multiple sclerosis25. It is thought that loss of regulatory T cell subsets, or abnormal immune

cell repopulation after depletion, may account for the increased incidence of many autoimmune

diseases, including anti-GBM disease, after exposure to this agent.

It is likely that these environmental triggers act in genetically susceptible individuals to induce

disease onset. Anti-GBM disease has a strong HLA-gene association, with approximately 80% of

patients inheriting an HLA-DR2 haplotype. A hierarchy of associations with particular DRB1 alleles

has been identified, some positively associated with disease (DRB1*1501, DRB1*0401) and some

conferring a dominant-negative protective effect (DRB1*07), which might be attributed to the higher

affinity of the latter alleles for binding peptides from the target autoantigen26. The DRB1*1501

association has been replicated in Asian populations27, 28. It should be noted, however, that these

susceptibility alleles are common in most populations and that they are also associated with other

autoimmune diseases (including multiple sclerosis, perhaps contributing to the association with

alemtuzumab treatment), highlighting that other factors are necessary to incite anti-GBM disease,

and thus HLA-gene testing is not routinely used in the clinical work-up of these patients.

Polymorphisms and copy number variation in non-HLA genes have also been implicated in disease

susceptibility, such as the genes encoding Fcγ-receptors29, 30, consistent with the role of pathogenic

autoantibodies in disease onset. Based on a small study, polymorphisms in the COL4A3, the gene

encoding the Goodpasture autoantigen, are not thought to be involved in disease predisposition 31.

To the best of our knowledge, there has not been an undirected genetic study in anti-GBM disease.

Immunopathogenesis

In its native form, the GBM consists of a network of type IV collagen molecules, each made up of

triple-helical protomers of α3, α4, and α5 chains (Figure 1). The principal target of the autoimmune

response in anti-GBM disease has been identified as the non-collagenous (NC1) domain of the alpha-

3 chain of type IV collagen [α3(IV)NC1; the ‘Goodpasture autoantigen’]32, 33. The clinical pattern of

reno-pulmonary disease reflects the restricted expression of this antigen to the basement

membranes of glomerular and alveolar capillaries (and to a lesser extent, the retina, choroid plexus

and cochlea, where it is generally not associated with clinical disease34). Two principle autoantibody

(B cell) epitopes within the autoantigen have been identified, designated EA and EB35, which in native

GBM are usually sequestered within the quaternary structure of the non-collagenous domains of the

triple helix of α3,4,5 chains.

Sera from all patients with anti-GBM disease appear to react to α3(IV)NC1, although a proportion

will also have antibodies directed against other collagen chains, including α5 and α4, identified

either in serum or upon elution from kidney tissue, and thought to arise via a process of ‘epitope

spreading’ following a primary response to the α3 chain36. The directly pathogenic potential of these

antibodies was clearly demonstrated by Lerner and colleagues in 1967, when they administered

antibodies eluted from the kidneys of patients with anti-GBM disease to non-human primates,

leading to the development of crescentic glomerulonephritis in the recipients5. The pathogenicity of

these antibodies has since been confirmed in a number of other species and animal models.

Clinical observations support a pathogenic role for these antibodies; antibody titre, subclass and

avidity have each been correlated with disease outcome37-40. In addition, the rapid removal of

circulating antibodies by plasma exchange is associated with better outcome, and if kidney

transplantation is performed in the presence of circulating antibodies, disease is likely to recur

rapidly in the allograft7, 41.

In addition to humoral responses, T cells also have a role in disease pathogenesis. Data from animal

models suggest that T cells may contribute directly to cell-mediated glomerular injury, which can

occur in the absence of significant humoral immunity42, 43, and glomerular T lymphocytes may be

observed in kidney biopsies taken from patients with active disease44, 45. The strong HLA association

and the presence of high affinity, class-switched autoantibodies also indicates a necessity for T cell

help in the development of the autoimmune response. Notably, mononuclear cells from patients

proliferate in response to α3(IV)NC1 at much higher frequency than do cells from healthy controls,

and the frequency of autoreactive T cells correlates with disease activity46-48. The pathogenic T cell

epitopes in humans, however, have not been consistently defined.

That these autoreactive T cells can be identified in healthy individuals, along with low level natural

autoantibodies49, suggests that tolerance to the α3(IV)NC1 antigen is not fully achieved during

immunological development. In addition, a rising titre of anti-GBM antibodies has been shown to

predate the onset of clinical disease by several months50, highlighting that several tolerance

mechanisms must be disrupted before disease occurs. One such breach of ‘peripheral’ tolerance is

disruption of the quaternary structure of the Goodpasture autoantigen, and in particular disruption

of the sulfilimine crosslinks that stabilise the association of opposing NC1 domains on individual

collagen chains (Figure 1). This may result in modification or exposure of usually hidden epitopes,

which is suggested to be a key event in the pathogenesis of disease36. This may account for the

association with aetiologic factors that may disrupt alveolar (e.g. smoking, inhalation of

hydrocarbons) or glomerular basement membrane (such as lithotripsy51, 52, and the other kidney

pathologies discussed below).

The recovery phase of anti-GBM disease is associated with a progressive fall in autoantibody titres

(even in the absence of immunosuppression) and a lower frequency of T cells reactive to α3(IV)NC1.

The emergence of a CD25+ suppressor T cell subset that may inhibit responses to α3(IV)NC1 has

been described53, suggesting that immunological tolerance to a3(IV)NC1 can re-established. This may

explain the rarity of clinical relapses in anti-GBM disease, and the association with lymphocyte

depleting therapy with alemtuzumab.

Clinical Presentation and Diagnosis

The majority of patients (80-90%) will present with features of rapidly progressive

glomerulonephritis. 40-60% will have concurrent lung haemorrhage, and a small minority of patients

may present with isolated pulmonary disease. ‘Atypical’ presentations are well recognised, and

discussed in more detail below. Central to the diagnosis of anti-GBM disease is the identification of

anti-GBM antibodies, either in serum or deposited in tissue, along with pathological features of

crescentic glomerulonephritis, with or without evidence of alveolar haemorrhage.

Serological testing:

In current practice, circulating anti-GBM antibodies are usually detected using commercially

available enzyme immunoassays or bead-based fluorescence assays, which typically use purified or

recombinant human or animal GBM preparations as antigenic substrate. Western blotting, using

similar GBM preparations, may be a more sensitive method for antibody detection, though it is not

widely available outside research laboratories. Indirect immunofluorescence using normal kidney

tissue is an alternative method, though this requires additional input from a kidney pathologist and

is prone to giving false-negative results. A proportion of patients who have demonstrable deposition

of IgG on the GBM by immunofluorescence, but who are negative for circulating antibodies by these

conventional techniques, may be positive when tested by highly sensitive biosensor assay54. In anti-

GBM disease, the pathogenic antibodies are usually of the IgG class, with IgG1 and IgG3 subclasses

predominating37, 38, though rare cases of IgA and IgG4-mediated disease have been described55, 56.

These antibodies may not be detected on routine assays.

Serological testing for anti-GBM antibodies is, by definition, an urgent laboratory test, and we

recommend that results should be available within 24 hours for patients presenting with RPGN,

particularly when there are contra-indications to kidney biopsy, since initiating treatment prior to

developing a need for renal replacement therapy may have a significant impact on outcome. It

should be noted, however, that approximately 10% of patients do not have identifiable circulating

antibodies with conventional assays, and so serological testing should not be the sole method of

diagnosis when kidney biopsy is available.

Deposited antibody:

Direct immunofluorescence for immunoglobulin on frozen kidney tissue has high sensitivity for

detecting deposited antibodies, and is the gold-standard for diagnosis of anti-GBM disease, typically

showing a strong linear ribbon-like appearance (Figure 2). An important caveat is that fluorescence

may be negative or unclear in cases with severe glomerular inflammation, where the underlying

architecture is so disrupted that the linear pattern may not be recognised. Other causes of linear

fluorescence should be considered (including diabetes, paraproteinaemias, lupus nephritis, and

rarely fibrillary glomerulonephritis). Immunoperoxidase techniques using paraffin-embedded tissue

may also be used, but may be less sensitive. Lung biopsies are not routinely used in the diagnosis of

anti-GBM disease, and in our experience, immunofluorescence on lung tissue is rarely informative.

Conventional direct immunofluorescence techniques will identify all IgG subclasses, though will not

differentiate the antigenic target of the kidney-bound antibody. Non-collagen chain antigens, such as

entactin, have been identified in historical case series, though their significance is not well

characterised. In addition to detecting deposited anti-GBM antibody, immunofluorescence may

demonstrate the presence of complement components, in particular C3 and C1q, along the GBM17. A

proportion of patients may also demonstrate immunoglobulins or complement deposition along

tubular basement membranes.

Renal biopsy findings:

Crescent formation is the histopathological hallmark of anti-GBM disease (Figure 3A-F). Large biopsy

series suggest that 95% of patients will have evidence of crescent formation on kidney biopsy, and

that in 80% of patients more than 50% of glomeruli will be affected. The average proportion of

affected glomeruli is approximately 75%14, 57. The proportion of crescents observed in the biopsy

correlates strongly with the degree of renal impairment at presentation17, 18. These crescents will

typically be of uniform age (Figure 3F), in contrast to other causes of RPGN such as AAV, where a

mixture of cellular, fibrocellular and fibrous crescents may be seen. Crescentic glomeruli are likely to

have areas of fibrinoid necrosis in the underlying glomerular tuft. Non-crescentic glomeruli may

similarly have segmental fibrinoid change (Figure 3A), though often they may appear completely

normal. In early or mild disease, segmental proliferative change may be seen, with infiltrating

neutrophils or mononuclear lymphocytes. In severe disease, rupture of Bowmans capsule, peri-

glomerular inflammation (Figure 3E), progressing to granuloma formation with multinucleate giant

cells, may be observed in a proportion. Given the acuity of disease onset, interstitial fibrosis and

tubular atrophy are uncommon in anti-GBM disease (unless there is pre-existing kidney pathology)

though interstitial inflammation may be observed.

Electron microscopy is of limited additional value in the diagnosis of anti-GBM disease, showing non-

specific features of crescentic glomerulonephritis including rupture of the GBM and extra-capillary

localisation of fibrin and proliferating cells. Electron-dense deposits are not seen in isolated anti-

GBM disease, though electron microscopy is necessary to exclude concomitant glomerular

pathologies, such as membranous glomerulonephritis, and may identify other diseases that may

cause linear fluorescence (such as fibrillary GN and diabetic GBM thickening).

Diagnosis of alveolar haemorrhage:

Diffuse alveolar haemorrhage may be evident clinically, or identified by radiological examination.

Broncho-alveolar lavage may identify hemosiderin-laden macrophages, a characteristic feature

alveolar bleeding, and may also be useful to exclude other pathologies, such as atypical infection. In

addition, pulmonary function testing, in particular the determination of the alveolar carbon

monoxide transfer factor (KCO) may assist with the differentiation of alveolar haemorrhage from

other causes of pulmonary infiltration. The utility of both bronchoscopy and functional testing,

however, may be limited by the clinical condition of the critically unwell patient.

Treatment

Standard treatment for anti-GBM disease includes plasmapharesis, to rapidly remove pathogenic

autoantibody, along with cyclophosphamide and corticosteroids, to inhibit further autoantibody

production and to ameliorate end-organ inflammation. The use of this combination of therapies was

first described in 197658, and they remain the core recommendation of the latest KDIGO guideline

for treating anti-GBM GN59. We have reproduced a recommended treatment schedule in Table 113.

The inclusion of plasmapheresis is supported by observational studies that suggest improved renal

and patient survival compared to historical cohorts treated with immunosuppression alone18, 60. In

addition, a large contemporaneous Chinese study of 221 patients suggested better outcomes in

patients who received plasmapheresis in addition to cytotoxic and corticosteroid therapy61. To date,

there has only been one randomised trial in anti-GBM disease, which compared the addition of

plasma exchange to cyclophosphamide and steroids. Although this study was small (n=17), the

groups not ideally matched at randomisation, and its treatment regimens not representative of

current practice, its findings supported the use of plasma exchange in anti-GBM disease 62. In

particular, it demonstrated a much more rapid fall in circulating anti-GBM antibodies and improved

kidney function in patients receiving plasmapheresis.

Immunoadsorption is an alternative form of extra-corporeal therapy that may be more efficient than

plasma exchange for the removal of pathogenic autoantibody (though conversely it may not remove

pro-inflammatory or pro-coagulant factors). In small series, it appears to have comparable outcomes

to plasma exchange therapy63, 64, and we note that a prospective, open-label study is planned to

study the kinetics of anti-GBM antibody removal using this technique (NCT02765789), which may be

considered an alternative depending on local availability.

In AAV, the equivalence of daily oral and pulsed intravenous cyclophosphamide in induction therapy

has been established in a large randomised controlled trial65. Nearly all published experience in anti-

GBM glomerulonephritis, however, has used daily oral dosing, and so we recommend this as the first

line approach in this disease. Since the risk of relapse is very low, and approximately only three

months of cytotoxic therapy is usually required, concerns about total cumulative dose of

cyclophosphamide are less relevant than in AAV. In our experience, high-dose intravenous

glucocorticoids are not required in the treatment of anti-GBM disease, provided the other

components of therapy, in particular plasma exchange, can be initiated promptly18.

The use of other immunosuppressive therapies in anti-GBM disease is less well described. There are

several reports of rituximab use, as either ‘add-on’ to standard therapy or as a substitute for

cyclophosphamide in patients who are intolerant66. Similarly, the use of mycophenolate mofetil and

cyclosporine has been reported in individual cases or small series67-69. There is insufficient evidence,

at present, to recommend their use in first line therapy, though they may be considered in patients

who have contra-indication or intolerance to conventional treatment.

In addition to targeted immunotherapy, patients may require immediate organ support; in larger

series, approximately half of patients require haemodialysis at the point of initial presentation 18.

There are limited data on how frequently artificial ventilation is required, though one small series

estimated that this occurred in 11% of patients with lung haemorrhage70. There are case reports of

successful use of extra-corporeal membrane oxygenation in patients with very severe lung disease 71-

73.

Outcome and Prognosis

Long-term follow up of the largest cohort of patients (n=71) all treated with the combination of

plasma exchange, cyclophosphamide and corticosteroids, from the Hammersmith Hospital, London

UK, suggests that it is effective in treating lung haemorrhage in >90%, and in preserving independent

kidney function in the majority of patients, including those who present with severe kidney

dysfunction18. In patients presenting with creatinine values <500umol/L, renal survival was 95% and

94% at 1- and 5- years respectively. In patients presenting with creatinine >500umol/L, but not

requiring immediate dialysis, renal survival was 82% and 50% at the same respective time-points. In

patients presenting with an initial requirement for dialysis, however, renal recovery occurred in only

8% at 1 year. Other reports have described similarly low levels of renal recovery in patients

presenting with dialysis-dependent kidney failure, with the highest rate of approximately 20%

recovery in one series66.

Predictors of poor renal outcome include severity of renal dysfunction at presentation, the

proportion of glomeruli affected by crescents, and oligoanuria at presentation17, 18, 74. In the

Hammersmith series, no patient who required haemodialysis and had 100% crescents on kidney

biopsy recovered renal function, and so withholding treatment (and its incumbent toxicity) is often

considered in these cases. An isolated case of renal recovery despite these findings 75, however,

highlights the need to consider all cases for treatment, with specific attention to other features that

might predict renal recovery on biopsy (such as concomitant acute tubular injury) and the ability of

patients to tolerate each component of therapy. A short trial of early treatment may be considered,

and rapidly tapered if there is no evidence of renal recovery within 2-4 weeks. In addition, the

potential benefit of a period of immunosuppression to expedite autoantibody clearance, thus

allowing earlier kidney transplantation, should be considered in suitable patients. We have used

rituximab monotherapy, for example, in patients with ESKD who have an identified live-donor for

transplantation, but remain anti-GBM antibody positive, though controlled evidence for this

indication is lacking.

A recent retrospective study from Australia and New Zealand (an ‘ANZDATA’ registry study) analysed

the long-term outcomes of 449 patients with ESRD due to anti-GBM disease, and found that their

survival was comparable to patients with ESRD of other causes, whether they remained on dialysis

or underwent kidney transplantation15. Chronic respiratory sequelae after alveolar haemorrhage are

uncommon70.

Relapse is rare in anti-GBM, occurring in fewer than 3% of patients in the Hammersmith series18. It is

usually associated with ongoing exposure to pulmonary irritants such as cigarette smoke and

hydrocarbons76, 77, and avoidance of these precipitants is an essential part of long-term management

of these cases. We recommend repeat kidney biopsy in cases of relapse with kidney involvement, in

order to secure an accurate diagnosis and to exclude concomitant pathologies such as AAV and

membranous nephropathy (discussed below). In confirmed cases, standard re-treatment with

cytotoxics and corticosteroids is usually indicated. In a patient with multiply relapsing alveolar

haemorrhage we have found treatment with rituximab beneficial.

Kidney Transplantation after Anti-GBM disease

Kidney transplantation performed in the presence of anti-GBM antibodies results in a high likelihood

of disease recurrence in the allograft, at frequencies of up to 50% in historical series 41. Most centres

therefore recommend a period of at least six months sustained seronegativity prior to undertaking

transplantation in patients who have reached ESKD due to anti-GBM disease59. Under these

circumstances, and with current immunosuppressive regimens, recurrent disease is rare; the

ANZDATA registry study found that 6 of 449 (2.7%) of patients developed biopsy-proven recurrent

anti-GBM disease, which lead to graft failure in 2 cases15. The frequency of other causes of graft

failure was similar to patients transplanted for ESKD of other causes, and overall patient and renal

survival in anti-GBM disease was similar to other groups in this study. These findings were somewhat

in contrast to a previous European study that suggested patient survival was favourable in patients

transplanted for anti-GBM disease compared to those transplanted for other primary kidney

diseases (though significant differences in age at transplantation may account for this apparent

difference in patient survival)78. The European study also reported a higher frequency of recurrent

disease (14%), although this may reflect differences in immunosuppressive use during an earlier era,

and the study did not comment on anti-GBM titres and their relationship to timing of

transplantation. In the current era, isolated case reports of recurrent disease still exist79.

Post-transplant Anti-GBM Disease in Alport Syndrome

Mutations in any of the genes which encode the α3, α4 or α5 chains may result in a failure to

produce the normal type IV collagen network present in GBM, and thus lead to progressive kidney

disease in Alport Syndrome. Mutations in the COL4A5 gene located on the X chromosome are most

common, giving rise to typical X-linked Alport syndrome, though autosomal recessive and dominant

disease are recognised with COL4A3 and COL4A4 mutations. After kidney transplantation, these

patients may develop anti-GBM antibodies as an alloimmune response to the neo-antigens

contained in ‘normal’ α3, α4 or α5 chains in the kidney allograft. In X-linked disease, these antibodies

do not recognise the individual EA and EB epitopes of the α3 chain recognised by sera from

Goodpasture’s patients, but rather a distinct, composite epitope on the α5 chain, that is not

sequestered within the native hexamer of the Goopasture antigen36. It should be noted that

commercially available anti-GBM assays, which are optimised to detect reactivity to the α3(IV)NC1

antigen, may fail to detect circulating antibodies in this setting. Anti-GBM antibodies may be

detected in 5-10% of Alport patients following transplantation, though the development of overt

glomerulonephritis in the allograft is less frequent (perhaps owing to the effects of maintenance

immunosuppression). When glomerulonephritis develops, however, it usually occurs early and

carries a high risk of graft loss80, 81. Repeated transplantation in this setting almost invariably leads to

more aggressive disease recurrence and rapid graft loss, and is undertaken at very high risk 82.

Individuals with large COL4A5 gene deletions are at increased risk of post-transplant anti-GBM

disease, and recent guidelines encourage the use of genetic testing to inform discussions regarding

the risk of de novo anti-GBM disease after transplantation83.

Other Variant Forms of Anti-GBM Disease

Double-positive anti-GBM and ANCA-associated GN:

The concurrence of ANCA and anti-GBM antibodies is recognised to occur at much higher frequency

than expected by chance alone. In some series, almost half of patients with anti-GBM disease have

detectable ANCA (usually recognising myeloperoxidase, MPO), and up to 10% of patients with ANCA

also have circulating anti-GBM antibodies84-86. The mechanism of this association is unclear, though it

has been shown that ANCA may be detected before the onset of anti-GBM disease, suggesting that

ANCA-induced glomerular inflammation may be a trigger for the development of an anti-GBM

response, perhaps by modifying or exposing usually sequestered disease epitopes in GBM50.

Conversely, a recent study found that up to 60% of anti-GBM cases also had antibodies directed

against linear epitopes of MPO, versus 24% recognising intact MPO. The authors hypothesise that

MPO-ANCA recognising linear and conformational epitopes may arise sequentially, via a process of

inter- and intra-molecular epitope spreading87. We recently analysed the outcomes of a large cohort

of these ‘double-positive’ patients from four centres in Europe, and found that they experience the

early morbidity and mortality of anti-GBM disease, with severe kidney and lung disease at

presentation, requiring aggressive immunosuppressive therapy and plasma exchange88. During long-

term follow-up, they relapsed at a frequency comparable to a parallel cohort of patients with AAV,

suggesting they warrant more careful long-term follow up and maintenance immunosuppression,

unlike patients with single-positive anti-GBM disease.

Anti-GBM disease associated with membranous nephropathy:

There are several reports of anti-GBM disease associated with membranous nephropathy, occurring

as a preceding, simultaneous, or succeeding diagnosis89, 90. As with the ANCA-association, it is

postulated that disruption of glomerular architecture by one disease reveals hidden epitopes that

allow the second process to occur. A rapid decline in kidney function in a patient with known

membranous nephropathy should raise suspicion of the development of superimposed crescentic

nephritis or anti-GBM disease, and re-biopsy is recommended. We suggest that these cases are

treated initially as for anti-GBM disease, though how they should be managed in the long-term is not

clear. The authors of a recent case report suggest that rituximab may be a useful agent to treat both

pathologies simultaneously91.

‘Atypical’ anti-GBM disease:

Unusual presentations of anti-GBM disease have been recognised for as long as the disease itself.

Wilson and Dixon’s original 1973 report, for example, included the case of a 14 year-old male who

had the incidental finding of linear IgG deposition on a kidney biopsy taken during splenectomy for

hypersplenism and a diagnostic workup for optic vasculitis, who was treated with steroids only, and

who had normal renal function after one year follow up7. There have been a number of series of

‘atypical’ cases published in recent years, often with less severe renal involvement than is seen in

the classic presentation of anti-GBM disease, though it not always clear whether these represent

distinct clinical sub-phenotypes or heterogenous cases on a spectrum of disease severity92-95.

The largest of these series, reported by Nasr and colleagues, described 20 patients with mild and

indolently progressive renal impairment, who had linear immunoglobulin deposition on kidney

biopsy, but without predominant features of crescentic glomerulonephritis, and without overt lung

haemorrhage95. Circulating anti-GBM antibodies were not detected using conventional assays, and

both patient and renal prognosis was good, with 90% and 85% survival at one year, respectively.

They estimated that these ‘atypical’ cases accounted for approximately 10% of anti-GBM cases at

their centre. Notably, half of the cases had light-chain restriction on immunofluorescence, though

the authors suggest that the pathological features were not in keeping with proliferative

glomerulonephritis with monoclonal immunoglobulin deposition. They suggest that differences in

the antigen specificity, immunoglobulin subclass, and/or the ability to fix complement and recruit

inflammatory cells, of these ‘atypical’ compared to ‘classic’ anti-GBM antibodies, account for the less

severe disease phenotype seen.

Another small but well-characterised series with a distinct clinical phenotype was recently described

in Sweden; it included four young females, who had severe lung disease, and minimal kidney

involvement, who were found to have IgG4 subclass anti-GBM antibodies that were not detectable

with conventional anti-GBM assays56. That two of these patients demonstrated higher signal in the

anti-GBM ELISA when using a non-denaturing buffer suggests that differences in epitope specificity

might also account for the negative testing seen with the routine assays, and supports the

hypothesis that differences in clinical presentation might be related to differences in the subclass or

target of the anti-GBM antibody.

Future Directions

Despite being one of the better characterised autoimmune diseases, unanswered questions remain

regarding the pathogenesis of anti-GBM disease, which may have important clinical implications.

These include the need to further characterise the variant forms of disease, and how differences in

antibody subclass or specificity might influence presentation, the appropriate use of treatment, and

outcomes. Better understanding of T cell functions, and in particular the role of regulatory cells that

may suppress disease, may have therapeutic significance, both in anti-GBM disease and other

autoimmune conditions. The induction of immunologic tolerance using mucosal administration of

GBM antigen has been described in experimental models96, which may likewise have therapeutic

potential. Finally, the inciting events that cause autoimmunity to GBM antigens remain unclear.

Idiotype-anti-idiotype interactions have been invoked in a recent study97, and the role of infectious

triggers that might operate via a similar mechanism in clinical disease induction could be explored

further.

As a rare disorder requiring immediate treatment, co-ordinating large, prospective studies in anti-

GBM disease is challenging. In addition, the efficacy of current treatment regimens, when started

early enough, is widely accepted. Future therapeutic studies, therefore, should perhaps focus on

identifying additional ‘add-on’ treatments that might improve outcomes in severe disease. We have

recently shown that treatment with fostamatinib, a spleen tyrosine kinase (SYK) inhibitor, effectively

reverses crescent formation in rodent models of anti-GBM disease98, 99 (and that intra-glomerular SYK

can be detected in patient kidney biopsies100) so it would be of interest to explore the use of this

agent in advanced clinical disease. Another interesting agent that has shown efficacy in experimental

models is IdeS (IgG-degrading enzyme of S. pyogenes), a streptococcoal enzyme that is able to cleave

both circulating and membrane bound immunoglobulin101. IdeS was safe and tolerable in early phase

human studies, and a clinical study in severe anti-GBM disease, where it may promote rapid

clearance of pathogenic IgG, has been proposed (EudraCT number: 2016-004082-39). Finally, large

multi-centre studies might aim to identify clinical and histopathological indicators that reliably

predict failure to respond to treatment, so that the toxicities associated with intensive

immunosuppression may be avoided in futile cases.

As an archetypal autoimmune disorder, such studies of anti-GBM disease and its experimental

correlates are likely to provide fresh insights into the mechanisms of renal autoimmunity. However,

it is the alarming clinical presentation, and the need for emergency treatment, often in critically

unwell patients, that underscores the need for clinicians to be mindful of this rare condition, the

pitfalls associated with its diagnosis, particularly in atypical and variant presentations, and the early

and appropriate use of immunosuppressive and extracorporeal therapies, in order to prevent

morbidity and to improve survival.

Tables

Table 1: Initial Treatment of Anti-GBM DiseaseAgent Details and Duration Cautions

Plasma exchange

Daily 4 L exchange for 5% human albumin solution. Add fresh human plasma (300-600 mL) within 3 days of invasive procedure (e.g., kidney biopsy) or in patients with alveolar haemorrhage. Continue for 14 days or until antibody levels are fully suppressed. Monitor antibody levels regularly after cessation of treatment as plasma exchange may require reinstatement if antibody levels rebound.

Monitor and correct as required: platelet count; aim > 70 × 109/L; fibrinogen; aim > 1 g/L (may require cryoprecipitate supplementation to support PEX); haemoglobin, aim for > 90 g/L; corrected calcium, aim to keep in normal range

Cyclophosphamide2-3 mg/kg/day given orally for 2–3 months. Reduce dose to 2 mg/kg in patients > 55 years.

Stop if leukocyte count falls to < 4 × 109/L and restart at reduced dose when recovered. Insufficient evidence to recommend use of IV cyclophosphamide.

Corticosteroids

Prednisolone 1 mg/kg/day (maximum 60 mg) given orally. Reduce dose weekly to 20mg by 6 weeks, then gradually taper until complete discontinuation at 6–9 mo.

There is no evidence to support the use of methylprednisolone, and it may increase the risk of infection

Prophylactic treatments

Prophylaxis against oropharyngeal fungal infection (e.g., nystatin, amphotericin, or fluconazole) while on high-dose steroids. Peptic ulcer prophylaxis (e.g., with PPI) while on high-dose steroid treatment. Prophylaxis against PCP (e.g., cotrimoxazole) while receiving high-dose corticosteroids and cyclophosphamide. Consider acyclovir for CMV prophylaxis. Consider prophylaxis against HBV reactivation (e.g., lamivudine) in patients who have evidence of previous infection (HBV cAb positive).

H2 receptor antagonists in those who are intolerant of PPI. Cotrimoxazole may contribute to leukopenia; monitor leukocyte count. Alternatives include nebulized pentamidine.

Abbreviations: cAB = core antibody; CMV = cytomegalovirus; GBM = glomerular basement membrane; HBV = hepatitis B virus; IV = intravenous; PCP = Pneumocystis jiroveci pneumonia; PEX = plasma exchange; PPI = proton pump inhibitor. Table adapted from reference13.

Figures

d

Figure 1: In its native form, the collagen IV network in the GBM consists of triple-helical protomers of α3, α4 and α5 chains (shown individually in 1A). The carboxy terminal domains of these α3α4α5 protomers form a trimeric ‘cap’ (1B), end-to-end association of which results in the formation of the hexameric NC1 domain (1C). The quaternary structure of this hexamer is stabilised by hydrophobic and hydrophilic interactions across the planar surfaces of opposing trimers, and reinforced by sulfilimine bonds cross-linking opposing NC1 domains. Two key autoantibody epitopes within α3(IV)NC1 have been described, designated EA (incorporating residues 17-31 towards the amino-terminus) and EB (residues 127-141 towards the carboxy-terminus), which in the native form are sequestered at the junction with α4 and α5 chains within the triple helical structure. Binding through 7s domains (shown in orange) completes the lattice-like structure of the Type IV collagen network (1D). (Reproduced from reference102)

Figure 2: Kidney biopsy immunofluorescence for IgG revealing linear deposits along the glomerular basement membrane, and weaker staining of Bowman’s capsule and tubular basement membranes.

Figure 3: Renal histopathology in anti-GBM glomerulonephritis. Panels (A-C) are haematoxylin and

eosin stained sections demonstrating in (A) segmental fibrinoid necrotizing lesion in early anti-GBM

GN; (B) small, circumscribed cellular crescent; (C) large, circumferential cellular crescent. Panels (D-

E) demonstrate the use of Jones methylamine silver stain to delineate glomerular and tubular

basement membranes, clearly identifying a segmental area of extra-capillary proliferation in (D).

Panel (E) demonstrates obliteration of the glomerular architecture and rupture of Bowman’s

capsule, with extravasation of red blood cells into the urinary space, and significant peri-glomerular

inflammation. Panel (F) shows adjacent glomeruli with synchronous cellular crescent formation

typical of anti-GBM disease.

Disclosures

The authors declare no financial conflicts of interest in relation to the published work.

References

1. Jennette JC, Falk RJ, Bacon PA, et al. 2012 revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides. Arthritis and rheumatism 2013; 65: 1-11.

2. Stanton MC, Tange JD. Goodpasture's syndrome (pulmonary haemorrhage associated with glomerulonephritis). Australas Ann Med 1958; 7: 132-144.

3. Goodpasture E. The significance of certain pulmonary lesions in relation to the etiology of influenza. Am J Med Sci 1919; 158: 863-870.

4. Scheer R, Grossman M. Immune aspects of the glomerulonephritis associated with pulmonary haemorrhage. Annals of internal medicine 1964; 60(6): 1009-1021.

5. Lerner RA, Glassock RJ, Dixon FJ. The role of anti-glomerular basement membrane antibody in the pathogenesis of human glomerulonephritis. The Journal of experimental medicine 1967; 126: 989-1004.

6. McPhaul JJ, Jr., Dixon FJ. The presence of anti-glomerular basement membrane antibodies in peripheral blood. Journal of immunology 1969; 103: 1168-1175.

7. Wilson CB, Dixon FJ. Anti-glomerular basement membrane antibody-induced glomerulonephritis. Kidney international 1973; 3: 74-89.

8. Canney M, O'Hara PV, McEvoy CM, et al. Spatial and Temporal Clustering of Anti-Glomerular Basement Membrane Disease. Clinical journal of the American Society of Nephrology : CJASN 2016; 11: 1392-1399.

9. McPhaul JJ, Jr., Mullins JD. Glomerulonephritis mediated by antibody to glomerular basement membrane. Immunological, clinical, and histopathological characteristics. The Journal of clinical investigation 1976; 57: 351-361.

10. Taylor DM, Yehia M, Simpson IJ, et al. Anti-glomerular basement membrane disease in Auckland. Intern Med J 2012; 42: 672-676.

11. Hirayama K, Yamagata K, Kobayashi M, et al. Anti-glomerular basement membrane antibody disease in Japan: part of the nationwide rapidly progressive glomerulonephritis survey in Japan. Clinical and experimental nephrology 2008; 12: 339-347.

12. Li FK, Tse KC, Lam MF, et al. Incidence and outcome of antiglomerular basement membrane disease in Chinese. Nephrology 2004; 9: 100-104.

13. Pusey CD. Anti-glomerular basement membrane disease. Kidney international 2003; 64: 1535-1550.

14. Jennette JC. Rapidly progressive crescentic glomerulonephritis. Kidney international 2003; 63: 1164-1177.

15. Tang W, McDonald SP, Hawley CM, et al. Anti-glomerular basement membrane antibody disease is an uncommon cause of end-stage renal disease. Kidney international 2013; 83: 503-510.

16. Savage CO, Pusey CD, Bowman C, et al. Antiglomerular basement membrane antibody mediated disease in the British Isles 1980-4. British medical journal 1986; 292: 301-304.

17. Fischer EG, Lager DJ. Anti-glomerular basement membrane glomerulonephritis: a morphologic study of 80 cases. American journal of clinical pathology 2006; 125: 445-450.

18. Levy JB, Turner AN, Rees AJ, et al. Long-term outcome of anti-glomerular basement membrane antibody disease treated with plasma exchange and immunosuppression. Annals of internal medicine 2001; 134: 1033-1042.

19. McAdoo SP, Pusey CD. Clustering of Anti-GBM Disease: Clues to an Environmental Trigger? Clinical journal of the American Society of Nephrology : CJASN 2016; 11: 1324-1326.

20. Perez GO, Bjornsson S, Ross AH, et al. A mini-epidemic of Goodpasture's syndrome clinical and immunological studies. Nephron 1974; 13: 161-173.

21. Wilson CB, Smith RC. Goodpasture's syndrome associated with influenza A2 virus infection. Annals of internal medicine 1972; 76: 91-94.

22. Gu QH, Xie LJ, Jia XY, et al. Fever and prodromal infections in anti-glomerular basement membrane disease. Nephrology 2017.

23. Donaghy M, Rees AJ. Cigarette smoking and lung haemorrhage in glomerulonephritis caused by autoantibodies to glomerular basement membrane. Lancet 1983; 2: 1390-1393.

24. Bombassei GJ, Kaplan AA. The association between hydrocarbon exposure and anti-glomerular basement membrane antibody-mediated disease (Goodpasture's syndrome). American journal of industrial medicine 1992; 21: 141-153.

25. Clatworthy MR, Wallin EF, Jayne DR. Anti-glomerular basement membrane disease after alemtuzumab. The New England journal of medicine 2008; 359: 768-769.

26. Fisher M, Pusey CD, Vaughan RW, et al. Susceptibility to anti-glomerular basement membrane disease is strongly associated with HLA-DRB1 genes. Kidney international 1997; 51: 222-229.

27. Yang R, Cui Z, Zhao J, et al. The role of HLA-DRB1 alleles on susceptibility of Chinese patients with anti-GBM disease. Clinical immunology 2009; 133: 245-250.

28. Kitagawa W, Imai H, Komatsuda A, et al. The HLA-DRB1*1501 allele is prevalent among Japanese patients with anti-glomerular basement membrane antibody-mediated disease. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2008; 23: 3126-3129.

29. Zhou XJ, Lv JC, Bu DF, et al. Copy number variation of FCGR3A rather than FCGR3B and FCGR2B is associated with susceptibility to anti-GBM disease. International immunology 2010; 22: 45-51.

30. Zhou XJ, Lv JC, Yu L, et al. FCGR2B gene polymorphism rather than FCGR2A, FCGR3A and FCGR3B is associated with anti-GBM disease in Chinese. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2010; 25: 97-101.

31. Persson U, Hertz JM, Carlsson M, et al. Patients with Goodpasture's disease have two normal COL4A3 alleles encoding the NC1 domain of the type IV collagen alpha 3 chain. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2004; 19: 2030-2035.

32. Saus J, Wieslander J, Langeveld JP, et al. Identification of the Goodpasture antigen as the alpha 3(IV) chain of collagen IV. The Journal of biological chemistry 1988; 263: 13374-13380.

33. Turner N, Mason PJ, Brown R, et al. Molecular cloning of the human Goodpasture antigen demonstrates it to be the alpha 3 chain of type IV collagen. The Journal of clinical investigation 1992; 89: 592-601.

34. Cashman SJ, Pusey CD, Evans DJ. Extraglomerular distribution of immunoreactive Goodpasture antigen. The Journal of pathology 1988; 155: 61-70.

35. Netzer KO, Leinonen A, Boutaud A, et al. The goodpasture autoantigen. Mapping the major conformational epitope(s) of alpha3(IV) collagen to residues 17-31 and 127-141 of the NC1 domain. The Journal of biological chemistry 1999; 274: 11267-11274.

36. Pedchenko V, Bondar O, Fogo AB, et al. Molecular architecture of the Goodpasture autoantigen in anti-GBM nephritis. The New England journal of medicine 2010; 363: 343-354.

37. Zhao J, Yan Y, Cui Z, et al. The immunoglobulin G subclass distribution of anti-GBM autoantibodies against rHalpha3(IV)NC1 is associated with disease severity. Human immunology 2009; 70: 425-429.

38. Segelmark M, Butkowski R, Wieslander J. Antigen restriction and IgG subclasses among anti-GBM autoantibodies. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 1990; 5: 991-996.

39. Cui Z, Zhao MH. Avidity of anti-glomerular basement membrane autoantibodies was associated with disease severity. Clinical immunology 2005; 116: 77-82.

40. Hellmark T, Segelmark M, Unger C, et al. Identification of a clinically relevant immunodominant region of collagen IV in Goodpasture disease. Kidney international 1999; 55: 936-944.

41. Choy BY, Chan TM, Lai KN. Recurrent glomerulonephritis after kidney transplantation. American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons 2006; 6: 2535-2542.

42. Dean EG, Wilson GR, Li M, et al. Experimental autoimmune Goodpasture's disease: a pathogenetic role for both effector cells and antibody in injury. Kidney international 2005; 67: 566-575.

43. Wu J, Hicks J, Borillo J, et al. CD4(+) T cells specific to a glomerular basement membrane antigen mediate glomerulonephritis. The Journal of clinical investigation 2002; 109: 517-524.

44. Bolton WK, Innes DJ, Jr., Sturgill BC, et al. T-cells and macrophages in rapidly progressive glomerulonephritis: clinicopathologic correlations. Kidney international 1987; 32: 869-876.

45. Nolasco FE, Cameron JS, Hartley B, et al. Intraglomerular T cells and monocytes in nephritis: study with monoclonal antibodies. Kidney international 1987; 31: 1160-1166.

46. Derry CJ, Ross CN, Lombardi G, et al. Analysis of T cell responses to the autoantigen in Goodpasture's disease. Clinical and experimental immunology 1995; 100: 262-268.

47. Zou J, Hannier S, Cairns LS, et al. Healthy individuals have Goodpasture autoantigen-reactive T cells. Journal of the American Society of Nephrology : JASN 2008; 19: 396-404.

48. Salama AD, Chaudhry AN, Ryan JJ, et al. In Goodpasture's disease, CD4(+) T cells escape thymic deletion and are reactive with the autoantigen alpha3(IV)NC1. Journal of the American Society of Nephrology : JASN 2001; 12: 1908-1915.

49. Cui Z, Zhao MH, Segelmark M, et al. Natural autoantibodies to myeloperoxidase, proteinase 3, and the glomerular basement membrane are present in normal individuals. Kidney international 2010; 78: 590-597.

50. Olson SW, Arbogast CB, Baker TP, et al. Asymptomatic autoantibodies associate with future anti-glomerular basement membrane disease. Journal of the American Society of Nephrology : JASN 2011; 22: 1946-1952.

51. Xenocostas A, Jothy S, Collins B, et al. Anti-glomerular basement membrane glomerulonephritis after extracorporeal shock wave lithotripsy. American journal of kidney diseases : the official journal of the National Kidney Foundation 1999; 33: 128-132.

52. Guerin V, Rabian C, Noel LH, et al. Anti-glomerular-basement-membrane disease after lithotripsy. Lancet 1990; 335: 856-857.

53. Salama AD, Chaudhry AN, Holthaus KA, et al. Regulation by CD25+ lymphocytes of autoantigen-specific T-cell responses in Goodpasture's (anti-GBM) disease. Kidney international 2003; 64: 1685-1694.

54. Salama AD, Dougan T, Levy JB, et al. Goodpasture's disease in the absence of circulating anti-glomerular basement membrane antibodies as detected by standard techniques. American journal of kidney diseases : the official journal of the National Kidney Foundation 2002; 39: 1162-1167.

55. Moulis G, Huart A, Guitard J, et al. IgA-mediated anti-glomerular basement membrane disease: an uncommon mechanism of Goodpasture's syndrome. Clin Kidney J 2012; 5: 545-548.

56. Ohlsson S, Herlitz H, Lundberg S, et al. Circulating anti-glomerular basement membrane antibodies with predominance of subclass IgG4 and false-negative immunoassay test results in anti-glomerular basement membrane disease. American journal of kidney diseases : the official journal of the National Kidney Foundation 2014; 63: 289-293.

57. Jennette JC, Thomas DB. Crescentic glomerulonephritis. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2001; 16 Suppl 6: 80-82.

58. Lockwood CM, Rees AJ, Pearson TA, et al. Immunosuppression and plasma-exchange in the treatment of Goodpasture's syndrome. Lancet 1976; 1: 711-715.

59. Kidney Disease: Improving Global Outcomes (KDIGO) Glomerulonephritis Work Group. KDIGO Clinical Practice Guideline for Glomerulonephritis. Kidney Int, Suppl 2012; 2: 139-274.

60. Simpson IJ, Doak PB, Williams LC, et al. Plasma exchange in Goodpasture's syndrome. American journal of nephrology 1982; 2: 301-311.

61. Cui Z, Zhao J, Jia XY, et al. Anti-glomerular basement membrane disease: outcomes of different therapeutic regimens in a large single-center Chinese cohort study. Medicine (Baltimore) 2011; 90: 303-311.

62. Johnson JP, Moore J, Jr., Austin HA, 3rd, et al. Therapy of anti-glomerular basement membrane antibody disease: analysis of prognostic significance of clinical, pathologic and treatment factors. Medicine (Baltimore) 1985; 64: 219-227.

63. Biesenbach P, Kain R, Derfler K, et al. Long-term outcome of anti-glomerular basement membrane antibody disease treated with immunoadsorption. PloS one 2014; 9: e103568.

64. Zhang YY, Tang Z, Chen DM, et al. Comparison of double filtration plasmapheresis with immunoadsorption therapy in patients with anti-glomerular basement membrane nephritis. BMC Nephrol 2014; 15: 128.

65. de Groot K, Harper L, Jayne DR, et al. Pulse versus daily oral cyclophosphamide for induction of remission in antineutrophil cytoplasmic antibody-associated vasculitis: a randomized trial. Annals of internal medicine 2009; 150: 670-680.

66. Touzot M, Poisson J, Faguer S, et al. Rituximab in anti-GBM disease: A retrospective study of 8 patients. Journal of autoimmunity 2015; 60: 74-79.

67. Mori M, Nwaogwugwu U, Akers GR, et al. Anti-glomerular basement membrane disease treated with mycophenolate mofetil, corticosteroids, and plasmapheresis. Clinical nephrology 2013; 80: 67-71.

68. Garcia-Canton C, Toledo A, Palomar R, et al. Goodpasture's syndrome treated with mycophenolate mofetil. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2000; 15: 920-922.

69. Kiykim AA, Horoz M, Gok E. Successful treatment of resistant antiglomerular basement membrane antibody positivity with mycophenolic acid. Intern Med 2010; 49: 577-580.

70. Lazor R, Bigay-Game L, Cottin V, et al. Alveolar hemorrhage in anti-basement membrane antibody disease: a series of 28 cases. Medicine (Baltimore) 2007; 86: 181-193.

71. Herbert DG, Buscher H, Nair P. Prolonged venovenous extracorporeal membrane oxygenation without anticoagulation: a case of Goodpasture syndrome-related pulmonary haemorrhage. Crit Care Resusc 2014; 16: 69-72.

72. Balke L, Both M, Arlt A, et al. Severe adult respiratory distress syndrome from Goodpasture syndrome. Survival using extracorporeal membrane oxygenation. Am J Respir Crit Care Med 2015; 191: 228-229.

73. Legras A, Mordant P, Brechot N, et al. Prolonged extracorporeal membrane oxygenation and lung transplantation for isolated pulmonary anti-GBM (Goodpasture) disease. Intensive Care Med 2015; 41: 1866-1868.

74. Alchi B, Griffiths M, Sivalingam M, et al. Predictors of renal and patient outcomes in anti-GBM disease: clinicopathologic analysis of a two-centre cohort. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2015; 30: 814-821.

75. Laczika K, Knapp S, Derfler K, et al. Immunoadsorption in Goodpasture's syndrome. American journal of kidney diseases : the official journal of the National Kidney Foundation 2000; 36: 392-395.

76. Liu P, Waheed S, Boujelbane L, et al. Multiple recurrences of anti-glomerular basement membrane disease with variable antibody detection: can the laboratory be trusted? Clin Kidney J 2016; 9: 657-660.

77. Gu B, Magil AB, Barbour SJ. Frequently relapsing anti-glomerular basement membrane antibody disease with changing clinical phenotype and antibody characteristics over time. Clin Kidney J 2016; 9: 661-664.

78. Briggs JD, Jones E. Renal transplantation for uncommon diseases. Scientific Advisory Board of the ERA-EDTA Registry. European Renal Association-European Dialysis and Transplant Association. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 1999; 14: 570-575.

79. Sauter M, Schmid H, Anders HJ, et al. Loss of a renal graft due to recurrence of anti-GBM disease despite rituximab therapy. Clin Transplant 2009; 23: 132-136.

80. Byrne MC, Budisavljevic MN, Fan Z, et al. Renal transplant in patients with Alport's syndrome. American journal of kidney diseases : the official journal of the National Kidney Foundation 2002; 39: 769-775.

81. Kashtan CE. Renal transplantation in patients with Alport syndrome. Pediatr Transplant 2006; 10: 651-657.

82. Browne G, Brown PA, Tomson CR, et al. Retransplantation in Alport post-transplant anti-GBM disease. Kidney international 2004; 65: 675-681.

83. Savige J, Gregory M, Gross O, et al. Expert guidelines for the management of Alport syndrome and thin basement membrane nephropathy. Journal of the American Society of Nephrology : JASN 2013; 24: 364-375.

84. Jayne DR, Marshall PD, Jones SJ, et al. Autoantibodies to GBM and neutrophil cytoplasm in rapidly progressive glomerulonephritis. Kidney international 1990; 37: 965-970.

85. Levy JB, Hammad T, Coulthart A, et al. Clinical features and outcome of patients with both ANCA and anti-GBM antibodies. Kidney international 2004; 66: 1535-1540.

86. Rutgers A, Slot M, van Paassen P, et al. Coexistence of anti-glomerular basement membrane antibodies and myeloperoxidase-ANCAs in crescentic glomerulonephritis. American journal of kidney diseases : the official journal of the National Kidney Foundation 2005; 46: 253-262.

87. Li JN, Cui Z, Wang J, et al. Autoantibodies against Linear Epitopes of Myeloperoxidase in Anti-Glomerular Basement Membrane Disease. Clinical journal of the American Society of Nephrology : CJASN 2016; 11: 568-575.

88. McAdoo SP. Double seropositivity for ANCA and anti-GBM antibodies: clinical characteristics, long-term outcomes, and frequency of relapse, in a multi-centre European cohort. Kidney international 2017 (accepted).

89. Basford AW, Lewis J, Dwyer JP, et al. Membranous nephropathy with crescents. Journal of the American Society of Nephrology : JASN 2011; 22: 1804-1808.

90. Jia XY, Hu SY, Chen JL, et al. The clinical and immunological features of patients with combined anti-glomerular basement membrane disease and membranous nephropathy. Kidney international 2014; 85: 945-952.

91. Bandak G, Jones BA, Li J, et al. Rituximab for the treatment of refractory simultaneous anti-glomerular basement membrane (anti-GBM) and membranous nephropathy. Clin Kidney J 2014; 7: 53-56.

92. Cui Z, Zhao MH, Singh AK, et al. Antiglomerular basement membrane disease with normal renal function. Kidney international 2007; 72: 1403-1408.

93. McAdoo SP, Tanna A, Randone O, et al. Necrotizing and crescentic glomerulonephritis presenting with preserved renal function in patients with underlying multisystem autoimmune disease: a retrospective case series. Rheumatology 2015; 54: 1025-1032.

94. Troxell ML, Houghton DC. Atypical anti-glomerular basement membrane disease. Clin Kidney J 2016; 9: 211-221.

95. Nasr SH, Collins AB, Alexander MP, et al. The clinicopathologic characteristics and outcome of atypical anti-glomerular basement membrane nephritis. Kidney international 2016; 89: 897-908.

96. Reynolds J, Abbott DS, Karegli J, et al. Mucosal tolerance induced by an immunodominant peptide from rat alpha3(IV)NC1 in established experimental autoimmune glomerulonephritis. The American journal of pathology 2009; 174: 2202-2210.

97. Reynolds J, Preston GA, Pressler BM, et al. Autoimmunity to the alpha 3 chain of type IV collagen in glomerulonephritis is triggered by 'autoantigen complementarity'. Journal of autoimmunity 2015; 59: 8-18.

98. McAdoo SP, Reynolds J, Bhangal G, et al. Spleen tyrosine kinase inhibition attenuates autoantibody production and reverses experimental autoimmune GN. Journal of the American Society of Nephrology : JASN 2014; 25: 2291-2302.

99. Smith J, Syed A, Bhangal G, et al. Treatment With a Spleen Tyrosine Kinase Inhibitor Reduced Inflammation and Protected Kidney Function in Experimental Renal Allograft Rejection. Transplantation 2014; 98: 27-27.

100. McAdoo SP, Bhangal G, Page T, et al. Correlation of disease activity in proliferative glomerulonephritis with glomerular spleen tyrosine kinase expression. Kidney international 2015; In Press.

101. Yang R, Otten MA, Hellmark T, et al. Successful treatment of experimental glomerulonephritis with IdeS and EndoS, IgG-degrading streptococcal enzymes. Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 2010; 25: 2479-2486.

102. McAdoo SP, Pusey CD. Anti-glomerular Basement Membrane Disease. In: Mackay IR, Rose NR, Diamond B, Davidson A (eds). Encyclopedia of Medical Immunology: Autoimmune Diseases. Springer New York: New York, NY, 2014, pp 50-56.