1. Role for HCV antigen detection: a new generation of assays
Blood Borne Virus Unit
Virus Reference Department
Centre for Infections
HPA Colindale
13 May 2019

2. Samples used for the study
Part 1: 94 acute phase seronegative plasma donors, 51 of which contained detectable RNA genotyped, titrated as appropriate Part 2: Plasma samples from 65 individuals in a randomised clinical trial of Ribavarin/IFN samples from first 14 days of treatment to assess early dynamics

7. 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

8. Part 2: 300 samples from 65 patients
HCV Ag log10 f/mole
HCV RNA Viral load log10 iu/ml

9. Part 2: Pre- or D3 samples from 59 patients

10. 49 RA
4.00
7.00
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 HCV Ag
5.00
6.00
7.00
log HCV RNA
3.50
6.00
3.00
5.00
2.50
4.00
2.00
log HCV RNA
log HCV Ag
3.00
1.50
2.00
1.00
0.50
1.00
0.00
0.00
Base D3 D7
D10
D14
W12
Time 64
Time
0.00
0.50
1.00
1.50
2.00
2.50
3.00
BASE D7
D14
W12
log HCV Ag
4.00
5.00
6.00
log HCV RNA

11. 257
292
0.5 1
1.5 2
2.5 3
3.5 4
Base D3 D7
D10
D14
W12
Time
log HCV Ag 5 6 7
log HCV RNA 4 6
3.5 5 3 4
2.5
log HCV Ag 2 3
log HCV RNA
1.5 2 1 1
0.5
Base D3 D7
D14
W12
Time
268
4.5 8 4 7
3.5 6 3 5
2.5
log HCV RNA 4
log HCV Ag 2 3
1.5 1 2
0.5 1
Base D3 D7
D14
W12
Time

12. 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?

13. Thanks to:
Prof Howard Thomas and colleagues for permission to use the “Mild Trial” samples
Paul Grant, UCL for HCV RNA data
Nigel Wallis, Phil Tuke, Siew Lin Ngui and colleagues in BBVU, VRD
Abbott Diagnostics for Architect reagents and support