Association of polymorphisms in the programmed cell death 1 (PD-1) and PD-1 ligand genes with ankylosing spondylitis in a Chinese population.

To investigate the association of the polymorphisms and haplotypes in the PD-1 and PD-1 ligand genes with ankylosing spondylitis (AS) in a Chinese population.A total of 196 Chinese patients with ankylosing spondylitis and 180 age- and sex-matched controls of the same ethnic origin were included in the study. The polymorphisms in PD-1 and PD-1 ligand genes were genotyped using polymerase chain reaction-restriction fragment length polymorphism, allele-specific PCR and fluorescence melting curve methods.The T allele of the PD-1 rs2227982 polymorphism was more frequent in the patient group than in the controls (28.53% vs. 17.22%; p=0.000). The frequency of the CT haplotype (PD-1 rs2227981 C allele and PD-1 rs2227982 T allele) was higher in the AS patient group comparing with the controls (odds ratio (OR)=1.845, 95% confidence interval 1.220-2.789). The C allele of the PD-L1 rs822336 polymorphism was also more frequent in the patients than in the controls (34.69% vs. 27.22%; p=0.007). However, we did not find any evidence of genetic association between PD-L2 rs1009759/rs6476985 polymorphisms and AS (p=0.371 and 0.061, respectively). No significant difference in the distribution of the PD-1 rs2227981 alleles was found in our population when comparing AS patients with control groups (p=0.226).The results support a major role for PD-1/PD-L1 polymorphisms in disease susceptibility of AS.