Ongoing hepatitis C replication inhibits improvements in the CD4 cell counts of HIV-positive patients taking antiretroviral therapy, Canadian investigators report in the July 31stedition of AIDS.
Researchers monitored changes in the CD4 cell counts of HIV-positive patients who had antibodies to hepatitis C virus. Falls in CD4 cell counts before HIV treatment was started, and increases in such counts after the initiation of antiretroviral therapy were compared between individuals who had spontaneously cleared hepatitis C, and those who had chronic infection with the virus.
Ongoing hepatitis C replication was associated with slightly higher CD4 cell count loss prior to starting HIV treatment. There was also clear evidence that individuals with chronic hepatitis C had blunted CD4 cell responses to antiretroviral therapy.
“Spontaneous clearance of HCV [hepatitis C virus] is independently associated with a better rate of CD4 cell recovery once ART [antiretroviral therapy] is introduced”, comment the investigators, who stress that their “findings were robust.”
Investigators from the Canadian Coinfection Cohort Study performed their research because there is uncertainty about the impact of hepatitis C co-infection on HIV disease progression. Moreover, they were concerned that earlier research exploring this question may have been limited because antibody status was used to define hepatitis C infection. A significant proportion of patients infected with hepatitis C spontaneously clear the infection, leading the researchers to postulate that the results of some studies could have been confounded because some individuals in the hepatitis C arm were in fact free from the infection.
“We found that CD4 cell progression is negatively affected by the presence of ongoing HCV replication in coinfected individuals taking ART”, write the investigators. They add, “elucidating the mechanisms by which this difference occurs and investigating the impact of HCV treatment on CD4 cell progression should be prioritized.”
The study’s authors conclude, “when successful, HCV treatment might have an important role not only in improving HCV related outcomes, but for HIV-related prognosis as well”.
Impact of hepatitis C viral replication on CD4 T-lymphocyte progression in HIV – HCV coinfection before and after antiretroviral therapy.
Potter, Martin; Odueyungbo, Adefowope; Yang, Hong; Saeed, Sahar; Klein, Marina B; for the Canadian Co-infection Cohort Study Investigators
AIDS. 24(12):1857-1865, July 31, 2010. doi: 10.1097/QAD.0b013e32833adbb5
Link to AIDS abstract