Interleukin-6 gene polymorphisms and serum erythropoietin and hemoglobin in hemodialysis Iraqi patients

Abstract

Chronic kidney disease (CKD) is characterized by elevated levels of pro-inflammatory cytokines. Interleukin-6 (IL-6) is a pleiotropic and pro-inflammatory cytokine involved in different biological activities such as hematopoiesis, inflammation, and acute-phase response. The rate of IL-6 synthesis and degradation is affected by single nucleotide polymorphisms. This study aimed to evaluate the frequencies of 174G/C IL-6 gene promoter polymorphism in Iraqi hemodialysis (HD) patient and to examine the association between the allelic variations and serum erythropoietin (EPO) and hemoglobin (Hb) levels. The frequencies of IL-6 gene polymorphism were studied in 70 chronic renal failure patients on maintenance HD (patients group) and in 20 healthy participants (control group). Genotyping of IL-6 gene was performed by conventional polymerase chain reaction-restriction fragment length polymorphism. The distribution of IL-6 genotypes between groups was similar, and GG genotype is the most frequent followed by CG and CC genotypes. Control group had a nonsignificant difference in serum EPO levels among different IL-6 genotypes, while patients with GG genotype displayed significant elevation in serum EPO with time, followed by CG and CC genotypes. No significant differences in Hb levels were observed in patients and control groups. A significant positive correlation was observed between serum EPO and Hb in control group with different IL-6 genotypes, while a nonsignificant negative correlation was observed in patients group throughout the study. CKD did not significantly alter IL-6 genotypes, and IL-6 gene polymorphism had a significant effect on serum EPO levels and a nonsignificant effect on Hb levels.