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37. Update on pathogenesis of NMOSD

Kazuo Fujihara, M.D.Department of MS TherapeuticsFukushima Medical University

MS & NMO Center, STRINSTohoku University

Japan

Teaching Course 12: Neuromyelitis optica spectrum disordersHall D

(October 25, 2017, Paris, France)

Scientific Advisory BoardsBayer Schering, Biogen Idec, Mitsubishi Tanabe, Novartis, Chugai, Ono, Nihon, Merck Serono, Alexion, Medimmune, Medical Review

Speaker HonorariaBayer Schering Biogen Idec, Eisai, Mitsubishi Tanabe, Novartis, Astellas, Takeda, Asahi Kasei, Daiichi Sankyo, Nihon, Cosmic Corporation

Research SupportBayer Schering, Biogen Idec, Asahi Kasei, Chemo-Sero-Therapeutic Research Institute, Teva, Mitsubishi Tanabe, Teijin, Chugai, Ono, Nihon,Genzyme Japan

Government FundingGrants-in-Aid for Scientific Research from Ministry of Education, Science and Technology and Ministry of Health, Welfare and Labor of Japan

Disclosure (Kazuo Fujihara, M.D.)

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International Consensus Diagnostic Criteria of NMOSD

NMOSD, the unifying term for the entire clin spectrum

1) AQP4-IgG-seropositive NMOSDOne Core Clinical Characteristic (ON, Acute MY, Brain Synd)

2) Seronegative NMOSDTwo or more Core Clinical CharacteristicsAdditional requirements (One of ON/MY/AP Synd, DIS, MRI)

No better explanation for the clin syndRed-flags: Findings atypical for NMOSD (OCB neg, <3VS, etc)

(Wingerchuk et al. Neurology 2015)

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2. Environmental Factors1) Infections

Para- or Post-infectious -- case reportsCMV, VZV, EBV, HAV, HIV, Dengue, Mycoplasma p, Tbc

Clostridium perfringens ABC transporter (homology to T cell epitope of AQP4)(Varin-Dover. Ann Neurol 2012, Cree, Ann Neurol 2016)

1. Host Factors1) Multiple autoimmune diseases & F>>M (AQP4-IgG+cases)2) Ethnicity and AQP4-IgG seroprevalence

7.9/105 in Martinique vs. 3.3/105 in Olmsted (Flanagan. Ann Neurol 2016)

Asian 1.57/105 , Others 0.57//105 in Australia-NZNo North-South gradient (Bukhari, JNNP 2017)

3) Familial NMO: 1% (Japanese survey)4) HLA-DRB1*1501 -- no association with NMOSD5) Copy number variations at specific TCR loci (Sato. Ann Neurol 2015)

Host and Environmental Factors in NMOSD

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1. NMO-IgG = AQP4-IgG (Lennon et al, JEM 2005)

2. AQP4 is a water channel richly expressed in CNS

3. AQP4-IgG binds to the extracellular domains of AQP4.

AQP4 (pink)

Astrocyte

AQP4-transfected CellsNMO-Patient’s IgG

4. AQP4-IgG predicts relapse. (Weinshenker, et al Ann Neurol 2006)

(Takahashi et al, Brain 2006)

Aquaporin 4 (AQP4) and AQP4-IgG

esp. in periventricular regions, spinal gray matter, andendfeet of astrocytes.

OUT

IN

NH2COOH

Loop A Loop ELoop C

M1

M23

Factors to influence sensitivity in AQP4-IgG assay

1. Cell-Based Assay > ELISA > Mouse Tissue-Based Assay

2. M23 > M1 (M23 forms orthogonal array of particles)

3. Other factors to lower sensitivity in Cell-Based Assay(1) Pre-fixed cells, (2) GFP tagging at N-terminus

OUT

IN

NH2COOH

Loop A Loop ELoop C

M1

M23

AQP4-M23 AQP4-M1

AQP4: Transmembrane protein

(Verkman et al, Methods Enzymol2012)

Cell-Based Assay

(Takahashi et al, Brain 2007)

AQP4 : Tetramer

Orthogonal Array of Particles (OAP)

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Pathological Features of NMO

(Lucchinetti et al, Brain 2002)

General Features:•Severe Demyelination

•Edema, Necrosis & Cavity

•Acute axonal swelling, Spheroids

•Myelin-laden Macrophages

Humoral Immunity & Vascular Pathology•Deposition of Immunoglobulins and

Complements in Vasculocentric Pattern

•Thickened and Hyalinized Vessel Walls

IgG C9neo C9neo

IgM KiM1P KiM1P7

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NMO MSLoss of AQP4 & GFAP in NMO Lesions

MBP

AQP4

GFAP

MBP

AQP4

GFAP

Lost & well demarcated

Preserved

Lostextensively

Relatively preserved

(Misu, TJEM 2006, Brain 2007)

(AQP4 & Ig, C9neo)

Higher magnification

Perivascular Deposit of Ig & C9neo & AQP4 loss

9(Yaguchi et al. MSJ 2012)

Pathological study of subacute encephalopathyin a pregnant woman with AQP4-IgG

Consciousness disturbance, aphasia, Rt hemiparesis, Extensive brain MRI lesions, AQP4-IgG-positiveOpen biopsy from Lt temporal lobe:

1) demyelination, loss of AQP4 and GFAP in WM,2) loss of AQP4 also observed in GM

consistent with the NMO SC pathology

Normal WM

Lesion

AQP4 GFAP

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Type 1: Active NMO lesions with C activation and Gra infiltration

Type 2: Cystic lesions with extensive tissue destruction

Type 3: Lesions resembling secondary Wallerian degeneration

Type 4: Lesions with selective loss of AQP4

Type 5: Active NMO lesions with astrocytic clasmatodendrosis

Type 6: Lesions with astrocyte dystrophy and primary demyelination

Six Different Lesion Types in NMO

(Misu et al, Acta Neuropathol 2013)

Six Lesion Types in NMO

Diverse mechanisms of tissue injury operate in the same patient

Complement-mediated cytotoxicity, necrotic

No complement deposition, apoptosis-like

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Pathomechanisms of AQP4-IgG+NMOSD

(modified from Verkman et al, Brain Pathol 2013)

Plasmabast

IL6

C5

CD27+Memory B Cell

MBP

NF, thin RNFL

GFAP, S100b

AQP4-IgG1

T Cell(Th17, Th1,

AQP4-T cell, etc)

protease

BBB Breakdown

(CD19intCD27highCD38highCD180--)Neutrophil Eosinophil

Mac

Mechanisms of NMO pathogenesis and therapeutic targets

(Pittock, Ann NY Aca Sci 2016)

(1) IL-6 inhibitorstocilizumab, SA237

(2) anti-CD20rituximab

(3) anti-CD19MEDI-551

(4) glutamate antagonists(5) AQP4-IgG blocking

aquaporumab(6) C5 inhibition

eculizumabC1 inhibitor

Cinryse(7) anti-neutrophil

sivelestat(8) anti-eosinophil

cetirizine, ketotifen

Blood

BBB

CNS

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Astrocyte

Severe Astrocytic Damage in AQP4-IgG+NMOSD

GFAP: glial fibrillary acidic protein (an astrocytic protein)

1) Pathogenicity of AQP4 Ab in vitro and in vivo

2) Astrocyte Pathology (AQP4 Loss, etc) in the Lesions

3) Low Myo-Isositol/Creatine Value on 1H-MRS

4) Remarkable High CSF-GFAP in Relapse

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(Ciccarelli et al, Ann Neurol2013)

(MIsuet al, Brain 2007, etc)

(Hinson et al, Neurology 2007, Bradlet al. Ann Neurol2009, etc)

(Takano et al, Neurology 201１)

GFAP MBP

Remarkably Elevated CSF-GFAP Levels in NMOSD

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2476

0.8 0.7

(Takano et al, Neurology 2011)

Astrocytic damage is far more severe than demylination in NMOSD

All AQP4-IgG+

1) CNS regions at high AQP4 expression

(Matiello et al, JAMA Neurol 2013)

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3) Astrocytes are devoid of Complement Regulators (CD46, 55, 59)(Peripheral organs express them)

Lesion distribution in AQP4-IgG+NMOSD

M1

M23

SC ONBSBr

(Pittock et al, Arch Neurol 2006)

2) Higher AQP4 expression in Optic nerve and spinal cord(at mRNA & protein levels)

(Saadoun et al, MSJ 2015)

4) Muscle: an Extra-CNS involvement in NMOSD ?HyperCKemia (Suzuki et al, Neurology 2010)

1) Increase of relapse in 6 months postpartum- An International Collaboration of Korea, Japan, UK and Portugal -

(Kim et al, Neurology 2011)

* P<0.005

Pregnancy PostpartumBefore Pregnancy

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2) Higher rate of miscarriage (Nour et al, Neurology 2016)

Pregnancy and AQP4-IgG+NMOSD

Experimental Study: AQP4-IgG can cause placental inflammation & fetal death (Saadoun et al, J Immunol 2013)

1) Axonal degenerative pathology of NMO ?

(Kawachi and Lassmann. JNNP 2017)

2) Glucose-regulated protein (GRP) 78 autoantibody associates with BBB disruption in NMOAn auto-ab to bind brain microvascular endothelial cellscauses extravasation of serum Alb, IgG & Fibrinogen into brain

(Shimizu et al. Sci Transl Med 2017)

Recent topics in NMOSD

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(Hemmer B, et al. Nature Rev Neurosci, 2002) (Sinmaz S, et al. J Neuroinflamm 2016)

Myelin oligodendrocyte glycoprotein (MOG)

(2010 Biochemistry Protein Projects)

139 AA

2ndary structure Human MOG-IgG Reactivity1. CC’-loop most commonly recognized2. No epitope spreading over time3. not recognize rodent MOG

(Mayer et al. J Immunol 2013)

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Severe Demyelination but No Astrocytopathyin MOG-IgG-Positive Definite NMO

31yo, MaleRt ON - Good recoveryAcute Myelitis (2W later) – Good recovery

CSF Cells 90, OCB negT2 lesions [C3-5, C6-T5 (central)]AQP4-IgG-Neg, MOG-IgG-Pos

CSF-MBP 1190pg/ml (normal <102)CSF-GFAP < 0.004ng/ml (Ikeda et al, Mult Scler, 2015)

a n t i - M O G + a n t i - A Q P 4 + M S

1

1 0

1 0 0

1 0 0 0

1 0 0 0 0

1 0 0 0 0 0

1 0 0 0 0 0 0

CSF-GFAP(ng/ml)

p < 0 .0 0 0 1 p < 0 .0 0 0 1

a n t i - M O G + a n t i - A Q P 4 + M S

0

2 5 0

5 0 0

7 5 0

1 0 0 0

1 5 0 0

3 0 0 0

4 5 0 0CSF-MBP(pg/ml)

p = 0 .0 4 1 8

p = 0 .0 1 6 8

〇：Myelitis●：Optic neuritis△：ADEM

(Kaneko K et al. JNNP 2016)

CSF-GFAP and -MBP (anti-MOG vs anti-AQP4+ vs MS)-- an international collaborative study (8 countries) --

I. MS type- II Pathology in biopsied brains of MOG-IgG+ cases

1. Konig et al. Arch Neurol. 2008

Early active inflammatory demyelination with deposition of Ig & C

49-yo white woman“CD-RRMS”, MOG-IgG positive

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2. Spadalo M, et al. Ann Clin Transl Neurol, 2015

II. Potential pathogenicity of MOG-IgG

1. NMO-MOG-IgG causes reversible lesions in mouse brain(independent of complement) (Saadoun et al, Acta Neuropathol Comm 2015)

2. MOG-IgG affects oligodendrocyte cytoskeleton (Dale et al, Neurol N2. 2014)

3. MOG-IgG+complement induces demyelination (depends on type I IFN) (Berg et al, J Neuroinflammation. 2017)

MRI and OCT in anti-MOG+ vs anti-AQP4+ ON

OCT (Anti-MOG+ vs Anti-AQP4+ ON eyes, 6 month follow-up)• cpRNFL 90.2 ± 10.5 vs 74.1 ± 14.9 µm (P = 0.022)• GCIP 57.0 ± 6.2 vs 46.1 ± 12.3 µm (P = 0.027)

(Akaishi T, J Neurol Neurosurg Psychiatry 2015)

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(Ogawa et al, Neurol Neuroimmunol Neuroinflamm, 2017)

4 adult male (23-39yo)

Encephalopathy(ON in two)

CSF cell ↑Cereb cort lesions(FLAIR high)

IVMP effectiveNo relapse

MOG-IgG+ unilateral cerebral cortical encephalitis with epilepsy

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AQP4-IG+, MOG-IgG+ and Seronegative NMOSDAQP4-IgG+(n = 166)

MOG-IgG+(n = 35)

Seronegative(n = 89)

p value

Onset Age 36 (4 – 78) 35 (3 – 79) 33 (10 – 80) 0.6770

Female Sex 88.6% (147) 54.3% (19) 64.0% (57) <.0001

Single Attack 16.3% (27) 42.9% (15) 38.2% (34) <.0001

Clinical Phenotype

NMO 60.8% (101) 11.4% (4) 21.4% (19)

LETM 29.5% (49) 25.7% (9) 55.1% (49) <.0001

Recur ON / Bil ON 9.7% (16) 62.9% (22) 23.6% (21)

EDSS (last visit)

Monophasic 6 (2 – 8.5) 2 (0 – 6) 4 (0 – 8.5) 0.0009

Recurrent 5 (1 – 8.5) 2 (0 – 8) 4 (0 – 7) <.0001

(Sato et al, AAN, Neurology 2014)27

Summary

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1. AQP4-IgG+NMOSDis an autoimmune astrocytopathic diseasehas distinct pathogenetic factors from MS

2. MOG-IgG+diseaseis a demyelinating diseasemy be caused by pathogenic MOG-IgGappear to have a wide clinical spectrum

3. Double seronegative NMOSDmay be heterogeneous