People with HIV may have hepatitis C but still test negative for antibodies

People with HIV who test negative for hepatitis C antibodies could nevertheless be infected with the liver virus according to a US study published in the Journal of Acquired Immune Deficiency Syndromes this month.

Investigators at Veterans Administration Medical Center at the University of Iowa recruited 131 of their HIV-positive patients and took blood samples. They were also asked to complete a questionnaire about hepatitis C risk factors and symptoms and alcohol consumption. A control population of 102 HIV-negative diabetes patients was also recruited. All the HIV patients were receiving HAART and none of the study population was being treated with hepatitis C therapy.

Tests were performed for the presence of hepatitis C RNA on whole blood and for hepatitis C antibodies on plasma. Of the HIV-positive sample, 31 (23.7%) tested positive for hepatitis C antibodies, as did 2% of the HIV-negative control population. When the whole blood samples of the hepatitis C antibody negative were tested for the presence of hepatitis C RNA, an additional 20 HIV-positive patients tested positive but none of the control population.

Testing of stored whole blood and serum samples showed that the average duration of hepatitis C viremia was 26.8 months, although the range varied from one month to 99 months. None of the people with detectable hepatitis C virus but negative for antibodies went on to develop antibodies to the virus in the course of the study.

When baseline characteristics were analysed, it was found that CD4 counts were lowest in the people with detectable hepatitis C RNA without antibodies (225 cells/mm³), and highest in those people with hepatitis C antibodies (392 cells/mm³).

Analyses of likely mode of hepatitis C transmission suggested that those with antibodies were more likely to have acquired the infection from blood products or from sharing injecting equipment, whilst those with detectable virus only were more likely to have acquired hepatitis C sexually. Abnormal liver function, indicated by peak ALT levels was also associated with contracting hepatitis C from blood products or needles.

The investigators conclude that “it seems prudent to consider HCV infection in HIV-positive persons who test negative for HCV antibodies”, particularly in people with abnormal liver function tests, and that sensitive PCR tests should be performed.