Inhibitors of kB-like gene polymorphisms in rheumatoid arthritis

Objectives To investigate the role of inhibitor of kB-like ( IkBL ) gene polymorphisms in the pathogenesis of rheumatoid arthritis (RA) in Taiwan. Methods One hundred and twenty-nine patients with RA and 110 healthy controls were enrolled in this study. Polymerase chain reaction (PCR)/direct sequencing was used to determine the polymorphisms of IkBL −421 8T/9T, −324 C/G, −262 A/G, and −62 A/T. PCR/restriction fragment length polymorphism was used to determine the IkBL +738 T/C polymorphisms. Results The genotype distribution of IkBL −421 was significantly different between DR4 (+) RA patients and DR4 (+) controls ( p = 0.02). The allele frequency of IkBL −421 8T was significantly higher in DR4 (+) RA patients than in DR4 (+) controls ( p = 0.004, OR = 7.2, 95% CI = 1.7–29.2). The allele carriage frequency of IkBL −421 8T also tended to be increased in DR4 (+) RA patients in comparison with DR4(+) controls ( p = 0.07, OR = 14.6, 95% CI = 1.4–147.0). We also found that the allele frequency of IkBL −62 T was significantly higher in RA patients than in controls ( p = 0.04, OR = 1.5, 95% CI = 1.1–2.1). The allele carriage frequency of IkBL −62 T tended to be increased in RA patients ( p = 0.08, OR = 1.7, 95% CI = 1.0–3.0). The estimated haplotype frequency of IkBL −421 8T/−62 T tended to be increased in RA patients compared with controls ( p = 0.07, OR = 1.4, 95% CI = 1.0–2.0). Conclusion The IkBL −62 T may be associated with the development of RA in Taiwan. The IkBL −421 8T may also be related to susceptibility to RA in HLA-DR4 (+) individuals. This study shows that the estimated haplotype IkBL −421 8T/−62 T tends to be associated with susceptibility to RA in Taiwan.