Association of psoriasis vulgaris with HLA class I and class II antigens in the Turkish population, according to the age at onset

Association of psoriasis vulgaris with HLA antigens reference to age at onset has been reported in different racial or ethnic populations. Our purpose was to determine the distribution of HLA markers in the Turkish population according to the age at onset of the psoriasis vulgaris. HLA class I and class II antigens were performed by serologic methods in a group of 100 Turkish patients with psoriasis and 201 control subjects. Patients with psoriasis were subdivided into two groups based on age at onset (below or above 40 years of age) and family history. The frequency of HLA A30, Cw3, Cw6, DR7, DR14, DQ8, and DQ9 antigens were significantly increased in the Turkish psoriatic patients whereas HLA A66, Cw2, Cw4 and DR11 were found to be negatively associated with psoriasis. However, there were striking differences in HLA antigens according to the age at onset of the disease. Type I, early onset was associated with a high frequency of A30, B50, Cw6 and DR7 antigens whereas patients with type II, late onset had an increased frequency of Cw7. We conclude that psoriasis is probably a genetically determined disease and suggest that HLA-Cw6 antigen seems to associate commonly with early onset of psoriasis in Turkish patients.