IDENTICAL HLA CLASS-II ALLELES PREDISPOSE TO DRUG-TRIGGERED AND IDIOPATHIC PEMPHIGUS-VULGARIS

In pemphigus vulgaris, a dermatological autoimmune disease, specific h uman leukocyte antigen (HLA) class II alleles, DR4 (DRB10402) and DRw 14 (DRB11401, in linkage disequilibrium with DQB1*0503), are thought to be susceptibility genes involved in the onset of the disease. We st udied the HLA class II alleles (DQA1, DQB1, DRB1 and DPB1) of 6 patien ts with pemphigus, in whom the disease was ''triggered'' by drugs cont aining sulphydryl or another sulphur-containing group. All patients ca rried the DRB10402 susceptibility allele, and one patient also carrie d the second susceptibility allele, namely DQB10503 (in linkage with DRB11401). Bacterial, viral or environmental agents are suspected to trigger the onset of autoimmune diseases. Our study demonstrated the p resence in patients with drug-triggered pemphigus vulgaris of the same HLA alleles thought to predispose to idiopathic pemphigus vulgaris. T his finding strengthens the notion that these HLA alleles may be true disease susceptibility genes.