blood borne virus unit virus reference department centre for infections hpa colindale
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24 April 2023
Blood Borne Virus Unit
Virus Reference Department
Centre for Infections
HPA Colindale
Role for HCV antigen detection: a new generation of assays
Samples used for the study
Part 1: 94 acute phase seronegative plasma donors, 51 of which contained detectable RNAgenotyped, titrated as appropriate
Part 2: Plasma samples from 65 individuals in a randomised clinical trial of Ribavarin/IFNsamples from first 14 days of treatment to assess early dynamics
Part 1 inferences to be drawn:-
• Proficient across limited selection of genotypes 1-3 available
• Linearity also maintained over 3 log10
• Interpolated LOD in range 2-3 log10
Part 2: 300 samples from 65 patients
HCV RNA Viral load log10 iu/ml
HC
V A
g lo
g 10 f
/mol
e
Part 2: Pre- or D3 samples from 59 patients
49 RA
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Base D3 D7 D10 D14 W12
Time
log
HC
V A
g
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
log
HC
V R
NA
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
Base D3 D7 D10 D14 W12
Time
log
HC
V A
g
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
log
HC
V R
NA
64
Time
0.00
0.50
1.00
1.50
2.00
2.50
3.00
BASE D7 D14 W12
log
HC
V A
g
0.00
1.00
2.00
3.00
4.00
5.00
6.00
log
HC
V R
NA
257
0
0.5
1
1.5
2
2.5
3
3.5
4
Base D3 D7 D10 D14 W12
Time
log
HC
V A
g
0
1
2
3
4
5
6
7
log
HC
V R
NA
292
log
HC
V A
g
0
0.5
1
1.5
2
2.5
3
3.5
4
Base D3 D7 D14 W12
0
1
2
3
4
5
6
log
HC
V R
NA
Time
268
Time
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Base D3 D7 D14 W12
log
HC
V A
g
0
1
2
3
4
5
6
7
8
log
HC
V R
NA
Part 2 inferences to be drawn:-
• Good correlation between HCV Ag quantitification and HCV RNA BUT NOT absolute, what is nature of the relationship?
• Response to R/IFN paralleled by both markers• Idiosyncrasies rare but significant, reason?• Qualitative therapy prediction possible early• Need to pin antigenaemia against HCV RNA for each
patient • Positioning- adjunct or alternative?• High risk population or resource-limited sites?
Thanks to:
• Prof Howard Thomas and colleagues for permission to use the “Mild Trial” samples
• Paul Grant, UCL for HCV RNA dataNigel Wallis, Phil Tuke, Siew Lin Ngui and colleagues in BBVU,
VRD
• Abbott Diagnostics for Architect reagents and support
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