By Liz Highleyman

In recent years, clinicians in several large cities in the U.K. and Europe have reported outbreaks of apparently sexually transmitted acute hepatitis C virus (HCV) infection, mostly among HIV positive gay and bisexual men.

Past studies have indicated that HIV negative people with acute hepatitis C have a high likelihood -- 50% or better -- of spontaneous HCV clearance without treatment, but spontaneous clearance may be less likely among HIV positive people due to compromised HCV-specific immune responses.

In a study presented at the recent 11th European AIDS Conference (EACS) in Madrid, Spain (October 24-27, 2007), researchers from the U.K., France, and Germany conducted a retrospective analysis of 150 HIV positive patients diagnosed with acute hepatitis C from 1999 through 2006 (defined as HCV seroconversion or a positive HCV RNA test within 12 months after a negative test).

Most study subjects (131) were gay/bisexual men, 5 were injection drug users, and 2 were in both risk groups. More than half (58%) had HCV genotype 1, though this varied from 21% in France to 68% in Germany; conversely, the prevalence of HCV genotype 4 was highest in France. At the time of acute HCV diagnosis, more than 60% were on HAART, most had HIV RNA below 400 copies/mL, and the median CD4 cell count was 433 cells/mm3.

Results

• Fewer than one-quarter of study subjects (21%) had symptoms of acute hepatitis C (most were diagnosed due to elevated liver enzymes).

• The median HCV viral load at the time of diagnosis was 5.93 log IU/L and the median baseline ALT level was 330 IU/L.

• 12 weeks after acute HCV diagnosis, 15% (n=23) had spontaneously cleared HCV (negative HCV RNA by PCR).

• 12 weeks after diagnosis, an additional 7% (n=11) cleared HCV, but 3 patients who previously had undetectable HCV RNA became HCV positive.

• 48 weeks after diagnosis, just 26% of the 23 patients with undetectable HCV RNA at week 12 remained HCV negative.

• Overall, only 7% of untreated patients (n=11) had sustained HCV clearance at 48 weeks.

• Factors that predicted spontaneous HCV clearance included:

- HCV genotypes other than 1 (i.e., 2, 3, or 4);
- Lower baseline HCV RNA (HIV RNA level had no effect);
- Higher CD4 cell count;
- Use of HAART.

Conclusion

The rate of sustained spontaneous clearance in this study (7%) was lower than that observed in some previous studies of HIV-HCV coinfected patients (as high as 25%), and much lower than that seen in studies of HCV monoinfected individuals (50% or better).

It was unclear from these findings whether the patients who became HCV RNA positive after apparently clearing acute HCV experience relapse or re-infection.

11/13/07

Reference
A Azwa, E Low, M Guiguet, and others. The natural history of acute hepatitis C in HIV co-infected individuals: a European collaborative study. 11th European AIDS Conference (EACS). Madrid, Spain. October 24-27, 2007. Abstract PS8/5.