Prevalence, risk factors and genetic characterization of human T-cell lymphotropic virus types 1 and 2 in patients infected with human immunodeficiency virus type 1 in the Cities of Ribeirao Preto and Sao Paulo

The aim of this study was to define the prevalence of human T cell lymphotropic virus types 1 and 2 in patients who were positive for human immunodeficiency virus type 1 in the State of Sao Paulo, Brazil. We evaluated 319 individuals infected with HIV type 1 who were attended at specialized clinics in two cities (Ribeirao Preto and Sao Paulo). The patients were interviewed and tested for antibodies against HTLV types 1 and 2 (Ortho HTLV-1/HTLV-2 Ab-Capture enzyme immunoassay). Direct DNA sequencing of polymerase chain reaction products from the tax region of HTLV type 2 and the long terminal repeat region of HTLV types 1 and 2 were performed to differentiate and determine the subtypes. The overall prevalence of anti-HTLV type 1 and 2 antibodies was 7.5% (24/319; 95% CI: 5.2-11.5). HTLV type 1 and 2 infection was associated with a history of injected drug use and with antibodies for hepatitis C virus (p < 0.001), but not with age (p = 0.2), sex (p = 0.9), sexual behavior or serological markers for sexually transmitted diseases (anti-Treponema pallidum, anti- human herpesvirus type 8 or anti- hepatitis B virus antibodies) (p > 0.05). HTLV DNA was detected in 13 out of 24 samples, of which 12 were characterized as HTLV subtype 2c and one as HTLV subtype 1a. Among the 12 HTLV type 2 samples, seven were from injected drug users, thus indicating that this route is an important risk factor for HTLV type 2 transmission among our population infected with HIV type 1.