An interluekin 1B allele, which correlates with a high secretor phenotype, is associated with diabetic nephropathy

Induction of interleukin 1 activates vascular endothelial and kidney mesangial cells, and increases production of type IV (basement membrane) collagen. Hence, genes within the interleukin 1 gene cluster are potential candidates in the pathogenesis of diabetic nephropathy. In a previously validated case-control study from Northern Ireland, consisting of 95 patients with insulin-dependent (type 1) diabetes and nephropathy (cases) and 96 patients with insulin-dependent (type 1) diabetes without nephropathy (controls), the authors performed PCR-based genotyping of specific DNA polymorphisms within the interleukin 1A, interleukin 1B, interleukin 1 (type 1) receptor and interleukin 1 receptor antagonist genes. The groups were matched for age at onset and duration of diabetes. A statistically significant increase was found in the allele frequency of the interleukin 1B*2 allele in cases compared to controls (chi2=7. 19, df.=1; P=0.007, Pcorr=0.028). The results of this study suggest that the interleukin 1B*2 allele, or a susceptibility factor in linkage disequilibrium with this allele, is associated with diabetic nephropathy in the Northern Ireland population.