Usefulness of a Fourth Generation ELISA Assay for the Reliable Identification of HCV Infection in HIV-Positive Adults from Gabon (Central Africa)

Abstract

Background/ObjectivesGuidelines for optimized HCV screening are urgently required in Africa, especially for patients infected with HIV, who sometimes show false positive or false negative reactivity in anti-HCV antibody assays. Here, we assessed the usefulness of a fourth-generation HCV Ag-Ab ELISA for the identification of active HCV infection in HIV-positive patients.MethodsThis cross-sectional study was conducted between 03/2010 and 01/2013 and included 762 Gabonese HIV-positive adult patients. The results of ELISA (Monolisa HCV Ag-Ab ULTRA, Bio-Rad) were compared with those obtained by RT-PCR (gold standard). The optimal ELISA signal-to-cutoff (S/CO) ratio to identify patients with active hepatitis C (positive HCV RNA) was determined. Specimens were further tested by the INNO-LIA HCV Score assay (Innogenetics) and the Architect HCV Ag kit (Abbott) to define the best diagnostic strategy.ResultsSixty-seven patients tested positive for HCV (S/CO ratio ≥ 1) by ELISA. Of these, 47 (70.1%) tested positive for HCV RNA. The optimal S/CO associated with active HCV infection was 1.7. At this threshold, the sensitivity of ELISA was 97.9% (95% confidence interval (CI) 90.0–99.9%), its specificity was 91.3% (95% CI 85.0–95.5%), and HCV seroprevalence rate was 7.3% (56/762) (95% CI 5.6–9.4%). Among 57 HCV-seropositive patients with available INNO-LIA results, false reactivity was identified in 14 (24.6%), resolved HCV infection in two (3.5%), possible acute HCV infections in nine (15.8%) and likely chronic HCV infections in 32 (56.1%) patients. HCV core Ag was undetectable in 14/15 (93.3%) specimens that tested negative for HCV RNA whereas it was quantified in 34 (out of 39, 87.2%) samples that tested positive for HCV RNA.ConclusionsOur study provides comprehensive guidance for HCV testing in Gabon, and will help greatly clinicians to improve case definitions for both the notification and surveillance of HCV in patients co-infected with HIV.

Hepatitis C Core Antigen Testing for Diagnosis of Hepatitis C Virus Infection

“…Demographic data were available in 21 studies, the remainder utilized anonymous specimens and authors were unable to provide further information. HIV status was known in 16 of the studies with three including only HIV co-infected subjects (60, 62, 65). HBV status was known in 13 studies and all but four excluded patients with HBV co-infection.…”

Low prevalence of hepatitis C virus RNA in blood donors with anti‐hepatitis C virus reactivity in Rwanda

“…High rates of nonspecific IgG reactivity against HCV have been shown related to low concentration of anti‐HCV as measured by low S/CO values, especially in African settings, and this has led to recommendations to change the cutoff values for the different serologic assays. For the CMIA assay used in this study, the Centers for Disease Control and Prevention in Atlanta, Georgia, has recommended an increase of the border value for anti‐HCV reactivity from the recommended S/CO of 1 to 5 or more .…”

Broad Range of Hepatitis B Virus (HBV) Patterns, Dual Circulation of Quasi-Subgenotype A3 and HBV/E and Heterogeneous HBV Mutations in HIV-Positive Patients in Gabon

“…In conclusion, besides HCV [ 21 ] and HDV [ 7 , 41 ], which are also highly prevalent in Gabon, we propose a new standardized diagnostic procedure for HBV screening in HIV-positive people from sub-Saharan Africa, before ART initiation ( Fig 7 ). In this algorithm, initial testing should be done using total HBcAb, and HBsAb allowing HBV vaccine to be further implemented in patients with no exposure to HBV [ 42 ].…”

“…Gender, age and ART were retrieved from patients’ files. CD4 + T-cell counts, HIV-1 RNA viral load (VL) measurements and HCV serology were performed in all patients at the time of sampling [ 21 ]. The study was approved by the Ethics Committee of Gabon (N°0021/2013/SG/CNE).…”