Simple and rapid screening for HLA-Cw*06 in Polish patients with psoriasis.

Summary Background.  The human leucocyte antigen (HLA) C allele Cw*06 is currently recognized as a major disease allele at the PSORS1 locus. It has been suggested that characterization of this gene could be used as a convenient criterion for classification of psoriasis phenotypes. Aim.  To design and optimize a DNA typing procedure, suitable for identification of HLA-Cw*06 and its zygosity status verification in large-scale analyses, and to test for its robustness in a case–control study. Methods.  PCR assays with sequence-specific primers (PCR-SSP) were used for specific detection of HLA-Cw*06. PCR with analysis of restriction fragment length polymorphism was used to distinguish between patients homozygous and heterozygous for HLA-Cw*06. Additionally, those homozygous for HLA-Cw*06 were screened for nonspecific digestion by degenerated PCR-SSP. This three-step procedure was used in the examination of 383 patients with psoriasis that developed at the age of ≥ 30 years of age and of 143 healthy subjects from northern Poland. Results.  A simple and rapid procedure for screening of HLA-Cw*06 was produced. A significant difference in HLA-Cw*06 frequency between patients with psoriasis and controls was seen (P = 0.02). Detailed examination of the age of disease onset among patients with psoriasis revealed that involvement of HLA-Cw*06 in the genetic background of psoriasis developing as late as the age of 45 years cannot be neglected. Conclusions.  The low cost, high-throughput capacity and requirement for small sample amounts make this procedure a useful one for HLA-Cw*06 typing in clinical practice and large population studies. We recommend that patients with psoriasis diagnosed before 45 years of age should be considered for diagnostic HLA-Cw*06 typing.