Association of KIR (Killer Cell Immunoglobulin-like Receptor) Genotype with Psoriasis in Korean Population

Abstract

Psoriasis is a multifactorial autoimmune skin disease with a pathogenesis that has remained obscure. Recently, T cells bearing natural killer receptors (NKRs) were precisely and strongly targeted as new putative pathogenic immunocytes in psoriasis. Among NKRs, killer cell immunoglobulin-like receptor (KIR) is the major molecule recognizing HLA class I allotypes and might be closely related to psoriasis. Methods: To investigate the association of KIR genotype and patients with psoriasis in Korean, we defined the 14 KIR genotypes in 96 patients with psoriasis and 86 healthy controls using PCR-SSP methods. Results: The frequencies of KIR2DS4 and KIR3DL1 were significantly decreased in psoriasis compared with controls (RR=0.21, 0.02). When patients were divided into two subgroups at the age of onset, type I (30 years) and type II (30 years) respectively, these phenomena were similarly observed independent of groups divided (type I: RR=0.26, 0.005; type II: RR=0.14, 0.0006). When the patients were divided into subgroups according to the age of onset and family history, the frequencies of KIR2DS4, KIR3DL1, and KIR2DS3 were significantly decreased in type I compared with type II psoriasis (3DL1, 2DS4: 0.004; 2DS3: 0.04) and were significantly decreased in psoriasis without family history compared to with family history (3DL1, 2DS4: 0.007; 2DS3: 0.05). The frequency of haplotype combination BB was significantly increased in psoriasis compared with controls (RR=2.74, 0.009). Conclusion: These results suggest that KIR genotype is a factor for the occurrence and development of psoriasis and in future how combinations of HLA and KIR genes influence psoriasis needs to be defined.