HLA-DRB1 and asthma: For Black participants, two MHC class II alleles, HLA-DRB1*03:01 and HLA-DQB1*02:01, were significantly associated with increased risk of being a late-onset asthma case [(OR = 4.00, 95%CI: 1.46 to 10.91; OR = 2.25, 95%CI: 1.09 to 4.65), respectively].