Multicenter evaluation of hepatitis C RNA levels among female injection drug users.

The purpose of this investigation was to identify factors that determine the blood level of hepatitis C virus (HCV) RNA. By use of a quantitative polymerase chain reaction assay, the level of HCV RNA was ascertained in stored serum samples from 676 women enrolled in a multicenter prospective investigation who were seropositive for anti-HCV antibodies. HCV RNA levels ranged from undetectable to 22.4x106 copies/mL in these women. Among the 520 women with detectable HCV RNA, levels were higher among those who were >41 years old and those who had human immunodeficiency virus (HIV) infection. After adjusting for age in a multivariate linear regression model, HCV RNA levels were more strongly associated with HIV RNA levels than with CD4(+) lymphocyte counts. However, <6% of person-to-person variance was explained by the factors evaluated. Additional research is needed to ascertain what determines the level of HCV RNA in blood.

Determinants of the quantity of hepatitis C virus RNA.

To test the hypothesis that person-to-person variability in blood levels of hepatitis C virus (HCV) RNA can be explained, the quantity of HCV RNA was assessed in 969 persons who acquired HCV infection in the context of injection drug use. Serum HCV RNA levels ranged from 200,000 to >120 million equivalents/mL (the linear range of the assay). The median log10 HCV RNA level was 0.46 higher in 468 human immunodeficiency virus (HIV)-positive persons than in 501 HIV-negative persons (P<.001). In addition, among HIV-negative persons, lower HCV RNA levels were independently associated with younger age (P<.001), ongoing hepatitis B infection (P=.005), and the absence of needle sharing (P=.02). However, >90% of the person-to-person HCV RNA level variability was not explained by these sociodemographic, environmental, and virologic factors. Additional research is necessary to ascertain what determines the level of HCV RNA in blood.

Screening for hepatitis C virus in human immunodeficiency virus-infected individuals.

Immunosuppression from human immunodeficiency virus (HIV) may impair antibody formation, and false-negative hepatitis C virus antibody (anti-HCV) tests have been reported in individuals coinfected with HIV and HCV. It is unknown if the frequency of false-negative tests is sufficiently high to change screening recommendations in this setting. Thus, the prevalence of false-negative results for anti-HCV by third-generation tests was determined with samples from HIV-infected individuals. Sera from 559 HIV-infected and 944 HIV-negative prospectively followed injection drug users were tested for anti-HCV by a third-generation enzyme immunoassay and for HCV RNA by using a branched DNA assay and the HCV COBAS AMPLICOR system. Of 559 HIV-infected participants, 547 (97.8%) were anti-HCV positive. One of the remaining 12 anti-HCV-negative participants was HCV RNA positive, and she later developed detectable anti-HCV. Of the 944 HIV-negative participants, 825 (87.4%) were anti-HCV positive. One of the remaining 119 anti-HCV-negative participants was HCV RNA positive, and she also developed detectable anti-HCV at a later visit. These data indicate that HIV infection does not alter the approach to hepatitis C virus screening, which should be performed with third-generation assays for anti-HCV unless acute infection is suspected.