Cytokine Polymorphisms and Predisposition to Diabetic Nephropathy: A Meta-Analysis

<b><i>Background:</i></b> Cytokine polymorphisms<i></i>might influence the predisposition to diabetic nephropathy (DN), but the results of already published related studies are still controversial and ambiguous. <b><i>Objectives:</i></b> The authors designed this meta-analysis to more precisely estimate relationships between <i>TNF-α/IL-1/IL-4/IL-8/IL-18</i>polymorphisms and DN by pooling the results of already published related studies. <b><i>Methods:</i></b> The authors searched Pubmed, Embase, Web of Science and CNKI for already published studies. Thirty already published studies were pooled and analyzed in this meta-analysis. <b><i>Results:</i></b> The overall pooled meta-analysis results showed that distributions of <i>TNF-α</i> –238 G/A, <i>TNF-α</i> –308 G/A, <i>TNF-α</i> –1031 C/T, <i>IL-1A</i> −889 C/T, <i>IL-1B</i> −511 C/T<i></i>and <i>IL-18</i> –137 G/C polymorphisms among patients and controls differed significantly. Additionally, we also found that distributions of <i>TNF-α –</i>308 G/A, <i>IL-1B</i> −511 C/T and <i>IL-18</i> –137 G/C polymorphisms among patients and controls from Asians differed significantly, and the distribution of the <i>IL-1B</i> −511 C/T polymorphism among patients and controls from Caucasians also differed significantly. <b><i>Conclusion:</i></b> The meta-analysis results demonstrated that <i>TNF-α</i> –238 G/A, <i>TNF-α</i> –308 G/A, <i>TNF-α</i> –1031 C/T, <i>IL-1A</i> −889 C/T, <i>IL-1B</i> −511 C/T<i></i>and <i>IL-18</i> –137 G/C<i></i>polymorphisms might influence predisposition to DN in the overall pooled population. Moreover, <i>TNF-α –</i>308 G/A, <i>IL-1B</i> −511 C/T and <i>IL-18</i> –137 G/C polymorphisms might influence predisposition to DN in Asians, whereas the <i>IL-1B</i> −511 C/T polymorphism might also influence predisposition to DN in Caucasians.