The Pilot study of HLA-CW06 allele frequency in Lithuanian patients with plaque psoriasis

Abstract

Background: Psoriasis is a common multifactorial chronic skin disease with a genetic background. The most significant association was observed with human leukocyte antigen (HLA) group. HLA-Cw6 is known as the most frequently detected HLA antigen associated with psoriasis, particularly early onset type of disease. Several studies of its association with various psoriasis clinical phenotypes and severity of the disease have been published so far; none in the Lithuanian population. Objectives: to determine the frequency of HLA-Cw6 in patients with plaque psoriasis and control group and tendency of association HLA-Cw6 antigen with types of psoriasis and familiar form of psoriasis. Methods: Forty nine patients (mean age 47.57 12.99) with plaque psoriasis and 56 unrelated persons (mean age 27.09 8.86) were included in study. Genomic DNA were extracted from peripheral blood leucocytes using salting out procedure. The genotyping of HLA C antigen group was performed using commercial Invitrogen company AllSet Gold HLA C Low Res SSP Kit. The PASI score (Psoriasis Area and Severity Index- a system of disease severity evaluation) was applied to each patient. The history of psoriasis in family were evaluated by questionnaire and classified as positive, when the disease was mentioned in biologic relatives (grandparents, parents, brothers or sisters). Results: Forty eight patients (98%) had early onset of diseases (at age less than 40 years) and one patient had late disease (2%). The seventeen patients (34.7%) had positive familiar history of psoriasis. PASI score 10 (moderate or severe plaque psoriasis) and more was found in 17 (36.2%) patients. The HLA-Cw6 antigen allele was detected in 29 of 48 patients with early onset of disease, 12 of 17 patients with positive familiar history of psoriasis and 13 of 17 patients with PASI score >=10. The frequency of HLA-Cw6 antigen allele was 3.06 (95% CI = 1.38 to 6.81) higher in psoriatic patients than in the controls. In our study