Objective: Hepatitis C virus [HCV] shares common transmission pathways with human immunodeficiency virus [HIV]. HIV-HCV co-infection is associated with negative impacts on both HIV and HCV when compare with mono-infection. Anti-HCV test is the main screening method for HCV infection. However, in HIV patients, false-negative anti-HCV may occur as a result of impaired immunity, and HCV RNA may be the sole investigation to diagnose HCV infection in those patients. Data regarding prevalences of both seropositive (anti-HCV+) and seronegative HCV (anti-HCV- but HCV RNA+) infection in HIV individuals in Thailand are limited. The aims of this study are to define the prevalence of seropositive and seronegative HCV infection in Southern Thai HIV patients.

Materials and Methods: This is a cross-sectional study in 2 centers in Southern Thailand: Songklanagarind and Songkhla Hospital. Inclusion criteria were known adult HIV patients with available CD4 count within 6 months of enrollment. Exclusion criteria were patients with coexisting autoimmune disease, renal dialysis, immunosuppressive therapy including corticosteroids treatment, and history or clinical condition that cannot exclude acute HCV infection. Plasma samples were obtained from all eligible patients and test for anti-HCV (third-generation enzyme immunoassay) and HCV RNA.

Results: A total of 117 HIV patients were enrolled, with mean age of 44 years and 51.3% were male. The median CD4 level was 524 cells/mm3. The major HIV transmission route was heterosexual (83.8%), and intravenous drug use [IVDU] was found 3.42% of patients. Nine patients (7.7%) were positive for anti HCV and, among those, HCV RNA was detectable in 8 patients (6.8%). However, no HCV RNA was detected in all patients with negative anti-HCV. When compared with no HCV co-infection group, lower CD4 count (343 vs. 549 cells/mm3; p = 0.035), more IVDU (33.3% vs. 0.9%, p = 0.001), lower heterosexual as a route of transmission (55.6% vs. 86.1%, p = 0.037), and more elevated aspartate aminotransferase [AST] level (31 vs. 24 U/L, p = 0.019) were observed in seropositive HCV group.

Conclusion: The prevalence of seropositive HCV infection in Southern Thai HIV patients was 7.7%. Low CD4 count, IVDU and elevated AST were significantly associated with HCV co-infection. No seronegative HCV infection was detected in our HIV patients.

Keywords: Hepatitis C, Seropositive, Seronegative, HIV, Negative anti-HCV, HCV infection, Chronic HCV, AIDS, Co-infection