Different Subtypes of Hepatitis C Virus Genotype 4 are Spread Among Human Immunodeficiency Virus Coinfected Patients in Argentina

FEDERICO BOLCIC; LEANDRO JONES; NATALIA LAUFER; JORGE QUARLERI

Boston, Estados Unidos

Conferencia; 18th Conference on Retroviruses and Opportunistic Infections (CROI 2011); 2011

Background: HCV genotype 4 (HCV-4) is common in the Middle East and in Africa and has recently spread to Europe. Its prevalence in Latin American countries is poorly known. We aimed to molecularly characteriza the HCV isolates from HIV-1 coinfected patients with phylogenetic relatedness inference, and to correlate this to an epidemiological niche.Methods: HCV genotype and viral load were determined from 383 HIV-1-HCV coinfected patients from May 2009 to May 2010. None was on HCV therapy. Age, gender and risk factors for HCV acquisition were documented. The genome from those individuals infected with genotype 4 was amplified and sequenced at the NS5B region. Phylogenetic and evolutionary rates were estimated by maximum likelihood, parsimony and Bayesian method. Mann-Whitney U and Chi squared test were used when correspond.Results: The frequency of HCV genotype distribution was: HCV-1, 73.4%; HCV-2, 2.1%; HCV-3, 17.5%; HCV-4, 3.7%; mixed genotypes, 3.3%. This result is consistent with the previously reported prevalence in Argentinean HIV-1 infected patients, except for a 4-fold increase in genotype 4 compared to 2005. The epidemiological characteristics of serotype 4 infected individuals were significantly different against HCV-2, as was the viral load vs. HCV-1.The genotype was more frequently found in men (77.8%) (p>0.05). The HCV-4  subtype inferred by Bayesian analysis, maximum likelihood and parsinmony shows that 67% was 4d, 22% 4a and 1% was 4m. No association was observed between age, gender or risk factor and genotype 4 subtype distribution.Conclusions: HCV-4 circulates in all transmission groups and is increasing among HIV-1 infected patients in Argentina. All HCV-4 isolates involved different risk groups (sexual transmission and intravenous drug users). Three different HCV-4 subtypes were identified, perhaps reflecting  that at least three forms of transmission occur. Future detection of genotype 4 is warranted considering that patients with genotype 4 chronic hepatitis C exhibit a similar rate of response to therapy tha genotype 1.