No evidence of association between functional polymorphisms located within IL6R and IL6ST genes and systemic sclerosis.

Systemic sclerosis (SSc) is a complex autoimmune disease which genetic component has not been yet completely understood. IL6 encodes a cytokine with a crucial role in the development of autoimmunity and fibrosis and its actions mainly are controlled by IL-6 receptor (IL-6R). We aimed to investigate whether the functional genetic variants rs8192284 and rs2228044 previously associated with several autoimmune diseases, located within the IL-6 receptor (IL-6R) subunits IL6R and IL6ST genes, respectively, are involved in the susceptibility to SSc and/or its major clinical subphenotypes. A Spanish cohort including 1013 SSc patients and 1375 controls was genotyped using the TaqMan® allelic discrimination technology. SSc patients were subdivided according to the major clinical forms, autoantibody status and presence of fibrotic lung affection. Our data showed no influence of the selected variants in global SSc susceptibility (rs8192284: P=0.67, odds ratios (OR)=0.98; rs2228044: P=0.99, OR=1.00). Similarly, the clinical/autoantibody subphenotype analyses did not yielded significant results. Our data suggest that the analyzed polymorphisms may not play a significant role in the SSc susceptibility.