Background: HBV/HIV co-infection is a growing problem. It is of interest to study the reciprocal influence of infections and effects of common treatments on mechanisms of antiviral resistance. To date, no studies about HBV/HIV-2 co-infection have been published. We aimed to analyze the epidemio-virological features of HBV infection in the Marseilles cohort of 34 HIV-2-infected patients.

Methods: HBV serological status were studied on the last available sample with the Axsym Abbott assays. HBV DNA was quantified with the Roche COBAS Monitor test. Direct HBV DNA sequencing was done using in-house protocols.

Results: Of 34 HIV-2-infected patients, 25 (74%) had serological markers of present or past infection; 3 (9%) showed vaccine immunization, and 6 (18%) were seronegative. Prevalence of HBV/HIV-2 co-infection was of 30% (vs 10% for HBV/HIV-1 co-infection in Marseilles; p <10-3); 7 patients were HBsAg⁺, with HBV DNA⁺ in all cases. HBV DNA was detected with Roche PCR for 8/9 HBV-infected patients (1 not tested). Of 8 patients with isolated anti-HBc, 7 were HBV DNA^- with Roche PCR. HBV sequences were obtained from 3 HBsAg^- patients (1 isolated anti-HBc and 2 anti-HBc⁺/anti-HBe⁺/antiHBs^-). HBV pol sequences from 7/10 HBV/HIV-2-co-infected patients were of genotype E while it was the case from only 3/79 HBV/HIV-1-co-infected patients (p <10-3); 3 were A. 1 HBV was E in pol and G in core, and 1 was A in pol and E in core. HBV from 0/4 HBeAg⁺ and 3/4 HBeAg^- HBV/HIV-2-co-infected patients were 1896A/G pre-core mutants. Mutations 1762A/T and/or 1764G/A were found in 2/4 HBeAg⁺ and 3/4 HBeAg^- patients. The M/V mutation in the YMDD domain was found in HBV and HIV-2 from 1 and 2 HBV/HIV-2-co-infected pts, respectively. When gender, age, nadir of CD4, plasma HIV-2 RNA levels were compared, no differences were observed neither between co-infected and HIV-2 mono-infected patients nor between HBeAg⁺ and HBeAg^- HBV-infected patients.

Conclusions: In Marseilles and the area, we found a high prevalence of HBV genotype E in HIV-2-infected pts. This seems related to an epidemiological link with sub-Saharan Africa in 28 of our 34 HIV-2-infected patients and to a high rate of sexual transmission, responsible of  90% of the HIV-2 infections. We found the rarely described E/G and A/E HBV pol/core genotypes. In 3 cases, serology failed to diagnose HBV infection. Further studies are needed on the reciprocal influence, the practical consequences on sero-molecular diagnosis, and the treatment of HBV/HIV-2-co-infections.

Keywords: HIV-HBV co-infection; HIV-2; HBV genotype E