Clinical, epidemiological and molecular features of the HIV-1 subtype C and recombinant forms that are circulating in the city of São Paulo, Brazil

Abstract Background The city of Sao Paulo has the highest AIDS case rate, with nearly 60% in Brazil. Despite, several studies involving molecular epidemiology, lack of data regarding a large cohort study has not been published from this city. Objectives This study aimed to describe the HIV-1 subtypes, recombinant forms and drug resistance mutations, according to subtype, with emphasis on subtype C and BC recombinants in the city of São Paulo, Brazil. Study design RNA was extracted from the plasma samples of 302 HIV-1-seropositive subjects, of which 211 were drug-naive and 82 were exposed to ART. HIV-1 partial pol region sequences were used in phylogenetic analyses for subtyping and identification of drug resistance mutations. The envelope gene of subtype C and BC samples was also sequenced. Results From partial pol gene analyses, 239 samples (79.1%) were assigned as subtype B, 23 (7.6%) were F1, 16 (5.3%) were subtype C and 24 (8%) were mosaics (3 CRF28/CRF29-like). The subtype C and BC recombinants were mainly identified in drug-naïve patients (72.7%) and the heterosexual risk exposure category (86.3%), whereas for subtype B, these values were 69.9% and 57.3%, respectively (p = 0.97 and p = 0.015, respectively). An increasing trend of subtype C and BC recombinants was observed (p < 0.01). Conclusion The HIV-1 subtype C and CRFs seem to have emerged over the last few years in the city of São Paulo, principally among the heterosexual population. These findings may have an impact on preventive measures and vaccine development in Brazil.

The authors would like to thank all the patients who participated in this study, ADEE3002 Group (Ambulatory Service of the Secondary Immunodeficiency Clinic of Clinical Hospital-HC/FMUSP), particularly Claudio R. Gonsalez, Lucas A. Medeiros, Ana Paula R. Veiga, Marcelo Mendonça and Eduardo R. Lagonegro. They would also like to thank Rosangela M. Araujo and Noemia Orii for the flow cytometry experiments, Jose Eduardo Martins for his assistance in determining HIV-1 viral loads, Dr Shirley Komninakis for kindly providing the envelope region primers, Fernando L. Melo and Anna Nishiya for their technical assistance. Lucio Martins, Andre Seiji Goto and Demetrius Vignati Alves da Silva for IT assistance. Fapesp, CNPq, LIM56/HC/FMUSP and FFM for support.