Association of interleukin-1 family cytokines single nucleotide polymorphisms with susceptibility to systemic sclerosis: an independent case-control study and a meta-analysis.

The aim of our study was to investigate the association of five single nucleotide polymorphisms in interleukin-1 (IL-1) gene with susceptibility to systemic sclerosis (SSc) in a Chinese population. A total of 58 SSc patients and 113 healthy controls were enrolled. TaqMan allele discrimination assay was performed to detect the genotyping of IL-1A -889C/T (rs1800587), IL-1B -511C/T (rs16944), IL-18 -607C/A (rs1946518), IL-18 -137G/C (rs187238) and IL-33 rs7044343. The association between these SNPs and SSc risk was analyzed. Furthermore, a meta-analysis of relevant studies on the association of IL-1A -889C/T (rs1800587) and IL-1B -511C/T (rs16944) with the susceptibility to SSc was performed. Through the genotyping, significant associations for SSc were found for: IL-1A -889C/T genotype frequencies (P = 0.000), dominant model (P = 0.000), recessive model (P = 0.001) and allele T frequency (P = 0.000). Among SSc patients, dyspnea was significantly associated with IL-18 -607C/A genotype frequency and IL-33 rs7044343 allele frequency (P = 0.037, P = 0.042, respectively). In addition, elevated erythrocyte sedimentation rate was significantly associated with IL-18 -137G/C (rs187238) genotype and allele frequency (P = 0.019, P = 0.006, respectively). While meta-analysis showed there was no significant association between IL-1A -889C/T polymorphism and SSc, for IL-1B -511C/T (rs16944), significant associations were found in the comparison of allele C versus T (OR 1.267, 95 % CI 1.016-1.580) by combined different outcomes. Results showed that IL-1A -889C/T (rs1800587) was associated with SSc susceptibility in the Chinese population. However, this association was not supported by a meta-analysis of all relevant studies. Further investigations are required to verify our findings.