HCV Viral Load and Interferon Levels in HIV/HCV Coinfected Patients

Research to date has produced conflicting data about whether HAART increases liver enzyme levels or hepatitis C virus (HCV) viral load levels in HIV/HCV coinfected patients. One hypothesis is that increased HCV viral load in such individuals may be due to changes in endogenous (natural) interferon-alpha production.

As reported in the July 2006 Journal of Acquired Immune Deficiency Syndromes, researchers measured transaminase (ALT and AST) levels, HIV and HCV viral load, and interferon-alpha levels in 30 coinfected patients receiving HAART at baseline and after 1, 2, 3, 6, and 9 months.

Results

Initiating HAART did not increase transaminase levels in a majority of cases.

HCV RNA and interferon-alpha levels did not change from baseline in patients with baseline HIV viral loads of 10,000 copies/mL or less.

In patients with baseline HIV viral loads above 10,000 copies/mL, after starting HAART:

- HCV RNA levels increased by 0.69 log;
- interferon-alpha decreased by -0.96 log;
- HIV RNA decreased by at least 0.5 log.

As HIV viral loads reached their nadir (lowest-ever level) approximately 4 months after initiation of HAART:

- HCV RNA levels remained 0.54 log above the baseline level;
- interferon-alpha levels stayed around 0.71 log below baseline level.

Conclusion

The authors concluded that patients in this study did not show evidence of HAART-related hepatoxicity. In patients with baseline HIV viral loads above 10,000 copies/mL, "suppression of HIV replication by HAART was associated with an increase in HCV titer and a decrease in endogenous interferon-alpha levels," but this was not observed among patients with lower pre-HAART HIV viral loads.

7/21/06

Reference
W A Bower, D H Culver, D Castor, and others. Changes in Hepatitis C Virus (HCV) Viral Load and Interferon-alpha Levels in HIV/HCV-Coinfected Patients Treated With Highly Active Antiretroviral Therapy. Journal of Acquired Immune Deficiency Syndromes 42(3): 293-297. July 2006.