HLA-Cw6 specificity and polymorphic residues are associated with susceptibility among Chinese psoriatics in Taiwan

Previous serotyping in Chinese patients has failed to confirm an association between HLA-Cw6 and psoriasis. As serotyping has proved to be less valuable in the determination of HLA-C, genotyping of HLA-C in 68 Taiwanese psoriasis vulgaris (PSV) patients was performed using polymerase chain reaction/sequence-specific oligonucleotide probe hybridization (PCR-SSOPH) of HLA-Cw genes. Compared to 213 non-PSV control subjects, HLA-Cw6 was significantly associated with PSV (16.18% of PSV patients vs 5.16% of controls; odds ratio 3.53, Pc/=10(-4)). The amino acid residues on the heavy chain of the HLA-Cw antigens from exon one to exon five were also analyzed. Asp 9, Ser 24, Ala 73, Asp 90, Trp 97, Trp 156 and Asn 77/Lys 80 were found to be positively associated with PSV ( Pc/=0.0044, 0.0008, 0.0026, 0.0014, 0.039, 0.0020 and 0.0000, respectively).