The role of HLA antigens in the aetiology of psoriasis.

AIM To investigate the association of the HLA-C allele with psoriasis. Methods Twenty five type I psoriasis patients with 25 healthy controls participated in this study. PCR-SSP was preferred for HLA-C typing. The patients were questioned for age at onset and family history and examined for severity and area of involvement of the disease and presence of articular, nail and scalp involvement. PCRSSP method was preferred for HLA-C typing. Statistical analyses were made using the Chi-square test. Relative risk was assessed to determine the association between disease and HLA antigen. RESULTS The increase prevalence of HLA-Cw6 antigen among type I psoriasis vulgaris patients (p=0.0047) compared with healthy controls was noticed, but not in the prevalence of other HLA-C alleles. Among psoriasis patients, 14 (56%) had a positive family history. Among all patients, eight (32%) had articular symptoms, 19 (76%) had nail involvement, and all subjects had scalp involvement. Onset of disease was 6.7 years earlier in patients with positive family history compared with negative family history. No significant association was found between HLA-C alleles and family history, clinical findings or severity of the disease. CONCLUSION Our findings are consistent with previous studies that have shown association between HLA-Cw6 antigen and early onset of the disease. Clarifying the role of HLA-Cw6 antigen in the etiopathogenesis provides important advances in gene therapy for psoriasis.