-572 G/C single nucleotide polymorphism of interleukin-6 and sepsis predisposition in chronic renal disease.

Single nucleotide polymorphisms (SNPs) of interleukin (IL)-6 are associated with the development of chronic renal disease (CRD). Their impact for sepsis in the field of CRD was investigated. One control cohort of 115 patients with CRD without infection and another case cohort of 198 patients with CRD and sepsis were enrolled. Genotyping at the -174 (rs1800795) and -572 positions of IL-6 (rs1800796) was done by restriction fragment length polymorphism. Circulating IL-6 was measured by an enzyme immunoassay. The GG genotype of rs1800796 was more frequent among cases (78.3%) than controls (62.6%). No difference in the genotype frequencies of rs1800795 between cases and controls were found. Odds ratio for sepsis was 2.07 (95%CI 1.24-3.44, p = 0.005) with the GG genotype of rs1800796, which was confirmed by logistic regression analysis taking into consideration the presence of chronic comorbidities. All-cause mortality until day 28 was similar between patients with the GG genotype and the GC/CC genotypes of rs1800796, but death caused from cardiovascular events not-related with infection was more frequent with the GG genotype (14.6% vs 2.4%, p = 0.031). Circulating IL-6 was greater among patients of the GC/CC genotypes of rs1800796 and multiple organ dysfunction (p = 0.013). The GG genotype of rs1800796 predisposes to sepsis in CRD and to 28-day mortality by sepsis-unrelated cardiovascular phenomena.