HLA-DRB1 and sarcoidosis: The most strongly and consistently associated risk factor for sarcoidosis is the major histocompatibility complex (MHC) region, comprising of HLA class I (HLA-A, −B, and -C) and class II (HLA-DP, −DQ, and -DR) genes, being HLA class II variants, particularly HLA-DRB1 and DQB1 the alleles most prevalently reported in association with sarcoidosis [60, 158].