Many BD patients are HLA-B51 negative, but with another Bw4 allele, which is not associated with BD, suggesting that in addition to HLA-B51, there are other gene play important roles in the development of BD.Mizuki and his colleagues1 and Park et al.29 suggested that MICA-TM alleles rather than HLA-B51 play an important role in the development of BD. This evidence concerns the gene MICA and Behcet disease.