HLA-DRB1 and chlamydia trachomatis infectious disease: Genotyping of commercial sex workers whose data previously demonstrated a correlation between Chsp60 antibody and risk of chlamydia PID identified DRB1, DQA1, and DQB1 alleles were predominant in this population; HLA DQA1*0401/DQB1*0402 heterodimer was associated with increased Chsp60 antibodies [19].