Acute/recent HCV infection in seronegative blood donors and IDUs, viral replication kinetics, immune response and disease outcome

Abstract number: p769

Tsertsvadze  T., Sharvadze  L., Dzigua  L., Chkhartishvili  N.

Objectives: 

Aim of the study was to reveal acute/recent HCV infection at the very early stage of infection in seronegative blood donors and Injecting Drug Users (IDUs) to observe the clinical course, viral replication kinetic, immune response and disease outcome.

Methods: 

A prospective 24 months follow-up study was performed in two different sub-groups: blood donors and Injecting Drug Users (IDUs). Namely, ELISA negative 3000 blood donors and 1000 IDUs were investigated on HCV RNA by qualitative PCR method. A pool of six blood specimens was applied for blood donors' testing and a pool of five blood specimens for IDUs. Further testing on individual samples was performed only for PCR positive pools. HCV antibodies were detected by ELISA and RIBA. HCV RNA (Qualitative and quantitative) by RT- PCR (Roche). HCV genotype- by Inno-Lipa. Detection of HCV RNA level (Viral load) was performed weekly for 6 months and then monthly. Cytokines were induced in whole peripheral blood cells using HCV core peptides and tested by ELISA.

Results: 

We revealed totally 11 patients with acute/recent HCV infection: five from blood donors, seven from IDUs. Among them four were symptomatic and seven asymptomatic. In all patients with acute/recent infection viremia was detectable 2 weeks after inoculation, it increased very rapidly and reached a peak titre by week 4. The viral titre was remarkably stable for the next 5–6–7 weeks, falling only two or three fold by week 9. After week 10 the viremia rapidly decreased: l >4 logs or l >5 logs by week 12 and it became either undetectable (<102 GE/ml) by weeks 14–15–16 (viral clearance), or virus was not eliminated and viral titre persisted in all follow up period (chronic infection). Among 11 subjects: two had genotype 1a, 5 -1b, 2-2a/2c and 2-3a. Out of 11 patients 3 cleared the virus, (two were symptomatic: 1-genotype 1b, 1 genotype 2a/2c and one asymptomatic- genotype 1a), while 8 developed chronic infection. In three subjects who cleared virus two had 1st type cytokine response (IL-2 and IL-12), in seven patients, out of eight who developed chronic infection cytokine synthesis was shifted towards Th2 response (IL-4 and IL-10).

Conclusion: 

There was some relationship between high viral titre and clearance from virus. Viral clearance was associated also with presence of Th1 immune response. There was no correlation between viral genotype and disease outcome.