Fitting into this concept, the author later proposed together with Turkish colleagues the term “MHC-I-opathy” [109] to explain how and why Behçet’s disease and several clinically distinct forms of SpA, all associated with MHC class I alleles such as HLA-B-51, HLA-C-0602, and HLA-B-27 and epistatic ERAP1 interactions, have a shared immunopathogenetic basis. This evidence concerns the gene HLA-B and Behcet disease.