The aim of this study was to investigate the association between the polymorphism of transporters associated with antigen processing (TAP1/TAP2) genes and rheumatoid arthritis in Chinese patients. A total of 100 RA patients and 99 healthy control subjects were enrolled. Analyses with polymerase chain reaction (PCR) based restrictions were used to identify the polymorphisms of the TAP1 and TAP2 genes, which were mapped on chromosome 6. There was a significant difference in the distribution of the TAP2 gene codon 565 polymorphism frequency between the RA patients and healthy control subjects (p<0.001). The odds ratio for the risk of the 'A' allele in RA patients was 1.60 (95% CI: 0.82-2.92). No statistical associations in the distribution of the TAP1 gene polymorphism frequency were found between RA patients and controls. There were some physical links found between TAP1/TAP2 gene polymorphism loci. However, there was no linkage observed from TAP1/TAP2 gene polymorphisms and HLA-DRB1*04 between RA patients and healthy controls. We concluded that the TAP2 gene codon 565 'A' allele was associated with RA in Chinese patients in Taiwan. Individuals possessing the 'A' allele had a higher incidence of RA. A lack of association of TAP1 gene polymorphisms between RA patients and healthy individuals was noted. The results of this study provide genetic evidence that TAP2 gene codon 565 polymorphism may play a role in RA.
