Objective: To study the genetic effects of various inflammatory cytokines on peritoneal solute transport rate (PSTR) in incident Korean peritoneal dialysis (PD) patients.
Design: Case-control association study.
Methods: 132 patients with baseline peritoneal equilibration test within 1-3 months after starting PD were enrolled. We analyzed the influence of single nucleotide polymorphisms (SNPs) of interleukin-6 (IL-6; -572G/C, T15A), tumor necrosis factor-alpha (TNF-alpha; -1031C/T, -863C/A, -308G/A), and IL-10 (-1082A/G, -592A/C) on baseline PSTR. Clinical parameters such as age, gender, presence of diabetes mellitus, comorbidity, C-reactive protein, and residual renal function were also included as covariates.
Results: The T15A SNP of IL-6 (rs13306435) was associated with PSTR. Patients with TA genotype (n=18) had significantly lower D4/P creatinine (0.65+/-0.087 vs 0.73+/-0.110, p=0.0046) and higher D4/D0 glucose (0.39+/-0.174 vs 0.31+/-0.119, p=0.027) than patients with TT genotype (n=114). The log value of the dialysate appearance rate of IL-6 had a strong positive correlation with D4/P creatinine (r2=0.1294, p<0.0001) and was significantly lower in the TA genotype than the TT genotype (201.7+/-14.42 vs 116.8+/-88.91 pg/minute, p=0.0358). By multiple logistic regression, TA genotype was negatively associated with a higher PSTR (high or high average; odds ratio 0.18; 95% confidence interval 0.048-0.666).
Conclusions: In incident Korean PD patients, T15A polymorphism of IL-6 is associated with dialysate IL-6 concentration and baseline PSTR.