Association of HLA-DQ and HLA-DR alleles with susceptibility or resistance to HIV-1 infection among the population of Chaco Province, Argentina.

The pathogenesis of infections clearly involves immunoregulatory host factors and products of Major Histocompatibility Complex (MHC) genes class 11 which present antigenic peptides to the T-cell receptor on CD4+ cells which in turn increase the production of specific antibodies and cytotoxic T lymphocytes. The objective of this study was to determine the frequency of the different alleles of HLA class II DQ and DR in HIV-1 infected patients of Caucasians with Guarani and Toba genetic backgrounds in an effort to determine the prevalence of certain alleles which could signify a factor of susceptibility to or protection against HIV-1 infection. A total of 54 HIV-1 positive patients and 46 healthy control subjects participated in the HLA-DQB1 study while 54 HIV-1 (+) patients and 57 healthy controls were analyzed for HLA-DRB1. Both HLA-DQB1 and HLA-DRB1 genotyping were performed using PCR and sequence-specific reverse hybridization oligonucleotide probe and analyzed with the UPA Key Typing System and UPA software. HLA-DQB1*0203 (P=0.041) and DRB1*01 (P=0.05) exhibited a decreased frequency in HIV-1 (+) patients while HLA-DRB1*13 (P=0.017) was observed more frequently. Several studies have reported different findings, depending on the populations analyzed. Our data show that there are HLA class II alleles associated with susceptibility or resistance to HIV-1 infection and that these differ among ethnic groups. We believe that our results differ from the other Caucasians populations due to the ethnic variability of Chaco inhabitants resulting from mixing between Caucasians and South American natives (Guaranies and Tobas).