Additionally, the HLA-A*01-B*08-DRB1*0301-DQB1*02 (DR3), HLA-B*14-DRB1*0102-DQB1*05 (DR1), and HLA-B*44-DRB1*0701-DQB1*02 (DR7) MHC haplotypes have all been associated with IgA deficiency, while the HLA-DRB1*1501-DQB1*06 (DR2) MHC haplotype has been shown to confer protection against IgA deficiency (36, 37). Here, HLA-DRB1 is linked to selective IgA deficiency disease.