Double risk of interleukin-37 rs3811047 A allele polymorphism with lupus nephritis in an Egyptian population

Aim of the work: To investigate the association of interleukin-37 (IL-37)(rs3811047) polymorphism with lupus nephritis (LN) in systemic lupus erythematosus (SLE) patients. Patients and methods: The case-control study included 206 SLE patients, 97 with LN and 109 without LN, and 240 healthy controls. SLE disease activity index (SLEDAI) was assessed. Genotyping of the IL-37 (rs3811047) polymorphism was done using real time polymerase chain reaction (PCR). A bioinformatic analysis of IL-37 was also performed. Results: The mean ages of SLE patients were 32.82 ± 10.43 years and female: male was 195:11 (F:M 17.7:1). The SLEDAI was significantly higher in the patients with LN (7.9 ± 6.6) compared to those without (1.9 ± 1.8) (p < 0.001). The AA genotype was more frequently represented in patients with LN (21.6%) compared to those without (7.3%) (p = 0.007), and carriers of AA genotype had four times increased susceptibility to acquire LN compared to GG and GA (OR: 4.1). Likewise, the A allele was more represented in patients with LN (43%) than in those without (30%)(p = 0.004), and the carriers of the A allele had nearly two times more risk of developing LN compared to carriers of G allele (OR: 1.79).The AA genotype was associated with LN susceptibility under the recessive genetic model (p = 0.002). Regression analyses revealed that A allele is an independent risk factor of proteinuria (p < 0.001), disease activity (p < 0.001), consumed C3 (p < 0.001) and C4 (0.003). Conclusion: The AA genotype of the IL-37 (rs3811047) SNP contributes to the development of SLE in Egyptian patients with a doubled risk of acquiring LN in carriers of the allele A.