Among eight SSc-associated susceptibility polymorphisms which were applied for meta-analysis, IRF5 rs2004640 polymorphism (OR 1.12; 95% CI 1.02-1.22, P = 1.39 × 10<sup>-2</sup>), STAT4 rs7574865 polymorphism (OR 1.25; 95% CI 1.07-1.47, P = 5.3 × 10<sup>-3</sup>), IRAK1 rs1059702 polymorphism (OR 1.20; 95% CI 1.05-1.37, P = 0.007), and CTGF G-945C polymorphism (OR 1.42; 95% CI 1.18-1.71, P = 0.002) are associated with PF status in SSc, while TNFAIP3 rs5029939, CD226rs763361, CD247 rs2056626, and IRF5 rs10488631 polymorphisms are not.
These findings indicate that upregulated CD226 expression on CD8(+) T cells reflects disease severity and is involved in SSc pathogenesis via the production of various cytokines, including profibrotic IL-13 and endothelial cell injury, and that CD226 may be a useful target in the treatment of SSc.
This meta-analysis demonstrates the CD226rs763361 polymorphism confers susceptibility to autoimmune disease in Europeans, South Americans and Asians, and in particular, shows that the CD226rs763361 polymorphism is associated with SLE, SSc and T1D.
Our data suggest that the tested genetic variants do not individually influence SSc susceptibility but a CD226 three-variant haplotype is related with genetic predisposition to SSc-related pulmonary fibrosis.
The most remarkable associations of the CD226 TT risk genotype were observed with the diffuse cutaneous SSc subtype, the anti-topoisomerase I antibody-positive, and SSc-related fibrosing alveolitis subsets: OR 1.86 (95% CI 1.42-2.43), P = 5.15 × 10(-6) , OR 1.82 (95% CI 1.38-2.40), P = 2.16 × 10(-5) , and OR 1.61 (95% CI 1.25-2.08), P = 2.73 × 10(-4) , respectively.