HLA-DRB1-ASTERISK-1502 ALLELE, SUBTYPE OF DR15, IS ASSOCIATED WITH SUSCEPTIBILITY TO ULCERATIVE-COLITIS AND ITS PROGRESSION

HLA-DRB1 allele typing was performed by the PCR-RFLP method on 59 ulce rative colitis (UC) patients and 136 healthy controls. Phenotypic freq uencies of HLA-B52 and DR2 were significantly increased among the UC p atients, serologically. DNA typing of HLA-DRB1 revealed that the genot ypic frequency of DRB11502 was higher in UC than in the controls (49. 2% vs 17.6%; P < 0.0001). In the analysis of clinical parameters, 82.8 % of patients bearing DRB11502 were treated with corticosteroids. DRB 11501 and DRB1*1502 differ in only one amino acid at residue 86 (vali ne vs glycine), and 66% of the UC patients carried two glycines at pos ition 86 in the HLA-DR beta-chain (vs 51% of control; P < 0.05). These observations suggest that the presence of Gly-86 in the HLA beta-chai n and surrounding amino acid sequence of HLA-DRB11502 is strongly ass ociated with susceptibility to UC.