Thus, alleles associated with the expression of MHC class II required for the presentation of various antigens to T-lymphocytes—HLA-DPA1/DPB1, HLA-DRB1 [113,114], HLA-DRB1*0301, HLA-DRB1*1101, HLA-DRB1*1201 [95], HLA-DQB1, and BTNL2 [115]–represent predispositions to the development of sarcoidosis in various localizations in patients. This evidence concerns the gene HLA-DRB1 and sarcoidosis.