ABSTRACT
BACKGROUND: The programmed death 1 (PD-1) protein, the product of the PDCD1 gene, is a negative regulator of T cells, and a genetic association of PDCD1 in systemic lupus erythematosus and rheumatoid arthritis (RA) in Caucasians has been reported. However, there have been no studies on the association of this gene and ankylosing spondylitis (AS). The aim of this study was to investigate the association of PD-1 polymorphisms with ankylosing spondylitis in the Korean population METHODS: One single-nucleotide polymorphism PD-1.9 T/C were genotyped in 95 patients with AS and 130 healthy controls in a case-control association study. We analyzed this SNP by use of a PCR-RFLP assay using genomic DNA. RESULTS: The T allele of the PD-1.9 polymorphism was significantly more frequent in a Korean male population with AS than in Korean male controls (21.0% versus 6.9%; odds ratio[OR] 1.89; 95% confidence interval [95% CI] 1.483-2.408). CONCLUSIONS: We demonstrated the presence of the PD-1 polymorphism in Korean AS patients. This finding suggests a genetic association between the PD-1 polymorphism and AS susceptibility.