Systemic lupus erythematosus with nephritis is strongly associated with the TNFB ∗2 homozygote in the Korean population

Abstract

To evaluate the association of TNFB NcoI polymorphism with SLE in the Korean population, we investigated the frequencies of the TNFB and HLA-DRB1 alleles in 281 controls and 97 SLE patients, including 56 patients with nephritis and 41 patients without nephritis. The frequency of the TNFB ∗2 homozygote in SLE was significantly increased over controls (43.3% vs 28.5%, RR = 1.9, p < 0.01). In SLE with nephritis, the TNFB*2 homozygote was more significantly increased (57.1% vs 28.5%, RR = 3.4, p < 0.0001), whereas there was no significant difference between SLE without nephritis and controls. The study of HLA-DRB1 alleles revealed the increased frequencies of DRB1 ∗02 and ∗03 (30.9% vs 18.2%, RR = 2.0, p < 0.01; 8.2% vs 2.1%, RR = 4.1, p < 0.05). There was no significantly different distribution of HLA-DRB1 alleles between SLE patients with nephritis and without nephritis. We found positive LD between TNFB ∗1 and HLA-DRB 1 ∗13, and between TNFB*2 and the particular DRB1 allele: ∗15, ∗04, and ∗07 in controls and/or in SLE patients. After stratification for each HLA-DRB1 allele, SLE with nephritis showed a higher frequency of TNFB ∗2 homozygote compared with the corresponding controls in DRB1 ∗15, ∗08, and ∗09 positives. Our results suggest that the TNFB ∗2 homozygote may be a strong susceptibility gene of SLE with nephritis in the Korean population.