HLA-DRB1 and tuberculosis: Since we found that HLA-DRB1*15, the highest frequency allele (18.32%) in whole studied active TB population, positively correlated with subjects with low antibody response levels rather than subjects with high antibody response levels (P = 0.005), which implies the loss of relevant antigens for screening of patients with this allelic group, it was necessary to investigate the potential association between the HLA-DRB1 alleles and antibody response to individual antigens.