Tuberculosis (TB), is still a problem of public health in Venezuela. By still unknown reasons onl... more Tuberculosis (TB), is still a problem of public health in Venezuela. By still unknown reasons only 30% of the individuals exposed are infected, 5% of them develop the illness within the first year of the infection and 95% remain in latency. The susceptibility to TB is multifactorial and genetic factors of the host play an important role. The aim of this study was to investigate the variability of HLA-DRB1 and HLA-DQB1 genes in patients with clinical diagnosis of pulmonary tuberculosis and healthy individuals exposed to the bacillus. We have examined these polymorphisms in a case-control study of 194 Venezuelan ethnically-mixed adults, including 93 patients with smear positive pulmonary TB (mean of age 37,9 years) and 101 unrelated healthy controls (mean age 41,4 years), selected of the Algodonal Hospital in Caracas. Definition of HLA variants was done using Dynal RELI SSO HLA Typing Kits. Allelic and genotypic frequencies were determined by direct count and the association was established as odd ratios (OR). DRB1*12 and DQB1*0602 frequencies were significantly increased in patients, while HLA-DRB1*03 and HLA-DQB1*0306 were increased in controls. The analysis of HLA-DQB1 alleles that encode or not aspartate at position 57 at the β chain (ASP-β57) showed the presence of the phenotypes: DQB1*0301-0302 (ASP-β57/No ASP-β57), DQB1*0301-0307 (ASP-β57/No ASP-β57) and DQB1*0202-0501(No ASP-β57/ No ASP-β57) only in patients. The DRB1*13-DQB1*06 haplotype was observed also increased in the controls vs. patients (OR: 0, 26; p: 0.031). The results suggest an influence of HLA polymorphism in the occurrence of TB in our patients.
Tuberculosis (TB), is still a problem of public health in Venezuela. By still unknown reasons onl... more Tuberculosis (TB), is still a problem of public health in Venezuela. By still unknown reasons only 30% of the individuals exposed are infected, 5% of them develop the illness within the first year of the infection and 95% remain in latency. The susceptibility to TB is multifactorial and genetic factors of the host play an important role. The aim of this study was to investigate the variability of HLA-DRB1 and HLA-DQB1 genes in patients with clinical diagnosis of pulmonary tuberculosis and healthy individuals exposed to the bacillus. We have examined these polymorphisms in a case-control study of 194 Venezuelan ethnically-mixed adults, including 93 patients with smear positive pulmonary TB (mean of age 37,9 years) and 101 unrelated healthy controls (mean age 41,4 years), selected of the Algodonal Hospital in Caracas. Definition of HLA variants was done using Dynal RELI SSO HLA Typing Kits. Allelic and genotypic frequencies were determined by direct count and the association was established as odd ratios (OR). DRB1*12 and DQB1*0602 frequencies were significantly increased in patients, while HLA-DRB1*03 and HLA-DQB1*0306 were increased in controls. The analysis of HLA-DQB1 alleles that encode or not aspartate at position 57 at the β chain (ASP-β57) showed the presence of the phenotypes: DQB1*0301-0302 (ASP-β57/No ASP-β57), DQB1*0301-0307 (ASP-β57/No ASP-β57) and DQB1*0202-0501(No ASP-β57/ No ASP-β57) only in patients. The DRB1*13-DQB1*06 haplotype was observed also increased in the controls vs. patients (OR: 0, 26; p: 0.031). The results suggest an influence of HLA polymorphism in the occurrence of TB in our patients.
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