CARATTERIZZAZIONE DELL'INFEZIONE DA VIRUS DELL'EPATITE B (HBV) IN UNA COORTE DI SOGGETTI HIV-POSITIVI IN MALAWI

Background. This study aimed at evaluating both HBV and occult HBV infection prevalence in a cohort of HIV-positive women receiving HAART. Methods. This retrospective laboratory-based study was performed on 1,006 plasma samples collected from women (median age:31 years; range:15-70 years) referred to DREAM centers in Malawi. Anti-HBc, anti-HBs and HBsAg markers were detected by commercial enzyme-immunoassays (Abbott/Murex). Samples resulted with an “anti-HBc-alone” serological profile were assessed by quantitative branched-HBV-DNA assay (SiemensDiagnostics). Samples under lower detection limit (<2,000 copies/ml) were tested by a semi-quantitative in-house PCR (lower detection limit: 350 copies/ml). Results. Overall, 56.3% samples were anti-HBc+. Of them 56.7% were anti-HBs+. The remaining 43.3% anti-HBs- samples were tested for HBsAg. 8.3% (83/1,006) of patients had an HBV chronic carrier serological profile. Of the 158 samples resulted with an “anti-HBc-alone” serological profile and tested by branched-DNA assay and/or in-house PCR , 85.8% was HBV-viremic. 12.8% (17/133) showed a plasmatic HBV-DNA viral load >104 copies/ml. 87.2% (117/134) of HBV-DNA-positive samples showed HBV-DNA plasma levels ≤104 copies/ml. The frequency of occult HBV infection among patients with an “anti-HBc-alone” serological profile was 75% (116/155). Conclusions. The prevalence of HBsAg-carriers in the study cohort was 8.3%, confirming Malawi as a high HBV endemic area. Detection of plasmatic HBV-DNA enabled to define an occult HBV infection in 75% of patients with an “anti-HBc-alone” serological status. This evidence underlines the need of introducing the use of HBV-DNA molecular assays as a diagnostic tool in African settings.