To investigate the role of inhibitor of kB-like (IkBL) gene polymorphisms in the pathogenesis of rheumatoid arthritis (RA) in Taiwan.
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.
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).
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.