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Epidemiology and Natural History of HIV/HCV Co-Infection
Tuesday, 1:30 - 3:30 pm
Background: GBV-C co-infection has been associated with delayed progression of HIV infection. We studied the effect of GBV-C co-infection on HIV-1 disease progression in a prospective cohort of homosexual men and controlled, besides prognostic factors at baseline, for CD4 counts during follow-up.
Methods: Since 1984, 326
homosexual men with an imputed date of HIV seroconversion enrolled in the
Amsterdam Cohort Studies with 3 to 6 monthly follow-up visits. The first sample
available after seroconversion and the last sample before 1996 were tested for
GBV-C RNA and anti-E2 antibodies. Censor date was
Results: Median follow-up
time was 8.9 years. Median time of first GBV-C test after seroconversion was
1.9 years (IQR 1.9 years) and between first and last test 7.4 years. In the
first sample, 137 (42%) tested positive for GBV-C RNA and 134 (41%) had
detectable anti-E2-antibody. Ten subjects gained and 79 lost GBV-C RNA during follow-up.
Participants with GBV-C RNA at first test were younger, had lower CD4 counts 1
year after seroconversion and had an increased risk of developing AIDS (HRadj
1.4, 95%CI: 1.1 to 1.9). After adjusting
for CD4 counts during follow-up HRadj became 1.0 (95%CI: 0.7 to 1.3). Participants who lost GBV-C RNA
had a significantly higher risk of AIDS compared with participants with
continuous absence of GBV-C RNA during follow-up (HRadj 2.8, 95%CI: 2.0 to 4.0). After correcting for CD4 counts
during follow-up, HRadj decreased to 1.6 (95% CI: 1.1 to 1.2). Anti-E2-antibody or GBV-C RNA
persistence, gain or continuous absence had no effect on HIV progression.
Analysis for survival time to death produced similar results.
Conclusions: Rather than a positive effect of GBV-C RNA on HIV progression our study shows that loss of GBV-C RNA has a negative effect on progression to AIDS or death. This effect of GBV-C RNA seems to be associated with changes in CD4 count during follow-up. Hence, we hypothesize that the persistence of GBV-C might depend on sufficient CD4 cell numbers and that the CD4 cell decline associated with HIV progression rather is a cause than a consequence of absent GBV-C RNA.
Keywords: GBV-C co-infection; HIV disease progression; seroconverters