Exon 2 variants (rs3811046 and rs3811047) of the IL37 gene are associated with susceptibility to systemic lupus erythematosus

Interleukin (IL)-37 is an anti-inflammatory cytokine that has recently been proposed to have an etio-pathogenic role in systemic lupus erythematosus (SLE). Two exon variants, rs3811046 G/T and rs3811047 A/G, of the IL37 gene have also been associated with susceptibility to some autoimmune disorders but have not been investigated in SLE. Therefore, this case-control study was conducted on 120 women with SLE and 120 healthy control women to explore the association between both variants and susceptibility to SLE. In addition, serum IL-37 levels were also determined. The TaqMan allelic discrimination method was used to genotype rs3811046 and rs3811047, while an ELISA kit was used to quantify IL-37 levels. IL-37 levels were significantly decreased in SLE patients compared to controls. Mutant alleles (T and G, respectively) as well as corresponding homozygous genotypes (TT and GG, respectively) of rs3811046 and rs3811047 were associated with a reduced risk of SLE. Haplotype analysis (in the order rs3811046–rs3811047) demonstrated that the T-A and G-A haplotypes were associated with an increased risk of SLE (2.53-fold and 2.45-fold, respectively). In conclusion, IL37 variants rs3811046 and rs3811047 were associated with reduced susceptibility to SLE among Iraqi women but were not associated with risk of active disease or lupus nephritis.