Methylation status of immune response genes promoters in cell-free DNA differs in hemodialyzed patients with diabetic nephropathy according to the intensity of anemia therapy.

BACKGROUND: Anemia is a major complication of end-stage renal disease. Hemodialysis itself is regarded as a stimulus activating inflammation. Pro-inflammatory cytokines are able to suppress erythropoiesis. In this pilot study, we analyzed the changes in methylation status of promoters of immune response genes in cell-free DNA to detect the differences between diabetic subjects (n = 18) with different therapeutic doses of recombinant erythropoietin. METHODS: The extent of promoter methylation of 24 genes in plasma cell-free DNA was examined before and after hemodialysis using EpiTect Methyl qPCR Array Inflammatory Response and Autoimmunity (Qiagen). RESULTS: The patients with higher methylation status of gene sequences IL13RA1, IL15, EDG3 and INHA in interdialytic interval were significantly overrepresented in the group with none or mild anemia therapy. CONCLUSION: The results are in agreement with the fact that IL13 and IL15 are known inhibitors of erythropoiesis and with considered immunomodulatory role of cell-free DNA.