Using a limited number of CVID patients, we showed previously that MHC haplotypes, including DRB1*04-DQB1*03:01-DQA1*03:01 and DRB1*01:01-DQB1*03:01-DQA1*05:05 confer susceptibility to CVID, while DRB1*07-DQA1*02:01 constitutes a protective haplotype (11). The gene discussed is HLA-C; the disease is common variable immunodeficiency.