The tumor necrosis factor ligand superfamily member 4 (TNFSF4) gene encodes a vital co-stimulatory molecule of the immune system and has been identified as a susceptibility locus for systemic lupus erythematosus, systemic sclerosis, and primary Sjögren's syndrome.
In TNFSF4, T allele and TT genotype of rs2205960, and G allele of rs1234313, were associated with pSS (p<0.05); T allele of rs2205960 was correlated with PBC (p<0.05) as a risk factor.
Weak associations were observed when the SNPs in TNFSF4 (rs2205960, rs844648 and rs704840) and FAM167A-BLK (rs7812879, rs2254546 and rs2618479) were directly analyzed or analyzed under dominant model between pSS and controls (all P<0.05).
EBF1, BLK and TNFSF4 are all involved in B-cell differentiation and activation, and we conclude that polymorphisms in several susceptibility genes in the immune system contribute to the pathogenesis of primary SS.