Association of IL-1beta, IL-1ra, and TNF-alpha gene polymorphisms in childhood nephrotic syndrome.

We investigated the association between IL-1beta, IL-1ra, and TNF-alpha gene polymorphisms and childhood nephrotic syndrome (NS). We analyzed the genetic polymorphism of IL-1beta, IL-1ra, and TNF-alpha genes in 152 patients with childhood NS and 292 healthy adult controls. The C to T exchange at position -511 of IL-1beta and the G to A at -308 of the TNF-alpha gene were genotyped. Five alleles of the IL-1ra gene were identified and designated as IL1RN1, IL1RN2, IL1RN3, IL1RN4, and IL1RN5, according to the variable number of tandem repeats in intron 2. The allele frequencies of IL-1beta1 (-511C), IL-1beta2 (-511T), TNF1 (-308G), and TNF2 (-308A) were 53.0, 47.0, 92.1, and 7.9%, respectively, in the childhood NS group. This was not significantly different from normal controls. In the childhood NS group, the allele frequencies of IL1RN1, IL1RN2, IL1RN3, IL1RN4, and IL1RN5 were 90.8, 7.6, 1.6, 0, and 0% [IL1RN1 odds ratio (OR)=0.296, P=0.0001, IL1RN2 OR=3.902, P=0.0002]. A high allele frequency of IL1RN2 and a lower allele frequency of IL1RN1 were found in childhood NS, although there was no association with IL-1beta and TNF-alpha. A high allele frequency of the IL1RN*2 allele may affect disease susceptibility in childhood NS.