Role of HLA-B and C alleles in development of psoriasis in patients from North India.

The association of HLA antigens with susceptibility for development of psoriasis vulgaris has been studied mostly using serologic methods. A number of different HLA class I antigens have been reported to be associated with predisposition to develop this disease. While Cw6 is the allele most commonly thought to confer risk for psoriasis, a number of HLA-B locus alleles have also been thought to be involved and, recently, in at least three studies, a specific amino acid in the HLA-C heavy chain has been implicated. With the recent development of molecular methods for typing for HLA class I alleles, it has become possible to re-examine this association by performing high resolution typing. In the present study we have investigated 38 psoriasis patients and 84 ethnically and geographically matched controls from North India. They were typed for HLA-B and HLA-C. The results showed the Cw*0602 was the main allele that was increased in this group of patients. The previously reported association with alanine-73 was not found to be significant. Cw*0602 was found in 71% of the patients. B*5701 and B*3701 were also increased but appeared to be secondary to linkage disequilibrium with Cw*0602.