Effect of coexisting HIV-1 infection on the diagnosis and evaluation of hepatitis C virus

Objectives: To evaluate the diagnostic accuracy of the test for antibodies to hepatitis C virus by enzyme-linked immunosorbent assay (anti-HCV ELISA-2 ) in patients with and without HIV-1 infection. Design: Cohort study. Methods: In all, 369 patients were tested and grouped by available serologi c tests. I-ICV RNA was quantified in these 369 patients using an Amplicor H CV (and/or HIV-1) Monitor, v1.0 test. Among 110 patients who were anti-HCV negative by ELISA-2, 39 were HIV/HBV coinfected and 71 had HIV alone. One h undred twelve patients were HIV/HCV coinfected and 147 patients had HCV inf ection alone. Results: Six of 110 (5.5%) ELISA-2 anti-HCV-negative, HIV-infected patients had circulating serum HCV RNA. Their median CD4 count was 36 cells/mm(3), which was significantly lower than that observed in the HIV/HBV group (medi an CD4 = 109, p < .001) or the HIV/HCV cohort (CD4 = 235; p < .0001). The p ositive predictive value of the ELISA-2 test for diagnosing ongoing HCV inf ection in HIV-infected patients was 91%, which is significantly better than that determined for the HCV group, 76% (p = .002) presumably because HCV i s less likely to resolve in the HIV patients. Mean alanine aminotransferase (ALT) levels were similar in the HIV/HCV (133 IU/L) and HCV (130 IU/L) coh orts. Median HCV RNA levels were higher in the HIV/HCV group (6.53 log(10) copies/ml) compared with the patients with HCV infection (5.62 log(10) copi es/ml; p < .00001). There was no significant correlation between HCV RNA le vels and ALT values, CD4 counts, or HIV RNA concentrations. Conclusions: The predictive value of the anti-HCV ELISA-2 test is better in HIV-coinfected patients than in patients infected only with HCV. False neg ative results, usually associated with acute infection or with Low CD4 coun ts, are uncommon. These patients may be diagnosed with the ELISA-3 assay or by reverse transcriptase polymerase chain reaction (RT-PCR). Compared with patients with only HCV infection, HIV/HCV patients display similar ALT pro files, but a higher proportion of detectable serum HCV RNA.