Objective: We investigated the relationship between polymorphisms in the TNF-a-induced protein 3 (TNFAIP3) gene and genetic susceptibility to SLE and RA in the Korean population.
Methods: The present case control study included 422 patients with RA, 133 patients with SLE and 422 healthy controls. Genotyping for TNFAIP3 gene polymorphisms rs5029941 (C>T), rs2230926 (T>G), rs5029930 (C>A), rs5029937 (G>T) and rs5029939 (G>C) in TNFAIP3 gene polymorphisms was performed. The status of RA-related autoantibodies, including RF and anti-CCP, in RA and the presence of arthritis and nephritis in SLE were assessed.
Results: Significantly different frequencies of minor alleles in two TNFAIP3 polymorphisms were found in patients with SLE compared with healthy controls [odds ratio (OR) 2.13, 95% CI 1.25, 3.65, P= 0.02 for rs5029937; OR 2.17, 95% CI 1.27, 3.72, P= 0.01 for rs5029939). Moreover, patients with SLE showed different frequencies of haplotypes compared with healthy controls (P<0.001). However, no association was found between RA susceptibility and TNFAIP3 polymorphisms (P= 0.28). Interactions between RA-related autoantibody status and TNFAIP3 polymorphisms were not associated with RA susceptibility. Interestingly, arthritis in patients with SLE was marginally associated with TNFAIP3 polymorphisms (P= 0.04).
Conclusion: The results suggest that TNFAIP3 gene polymorphisms are associated with differential susceptibility to SLE and RA in the Korean population. The relationship between TNFAIP3 gene polymorphisms and RA susceptibility may be dependent on ethnic background.