Relationship between vitamin D and immune system in chronic kidney failure patients on peritoneal dialysis

It is now well recognized that vitamin D has many biological functions beyond its classical role in bone metabolism. The aim of this study was whether supplementation of cholecalciferol in peritoneal dialysis with vitamin D deficiency would lead any chance in the pro-inflammatory cytokine IFN-? and the anti-inflammatory cytokines IL- 4 and IL-10, and pentraxin-3 and percentage of serum total leukocytes, granulocytes, lymphocytes, and peripheral blood mononuclear cell subpopulations (CD3, CD4, CD8, CD45)and CD4/CD8 ratio. We analyzed fasting blood samples from 31 (15 males, 16 females, mean age 48,6±14,8 yrs) continuous peritoneal dialysis patients for vitamin D status (serum 25-hydroxyvitamin D3 [25(OH)D3]) and specific plasma cytokine concentrations (interferon-gamma [IFN-?], interleukin [IL]-4, and IL-10), CD3, CD4, CD8 and CD45. Baseline mean 25(OH)D3 level was 6,1±2,1 ng/dL and after cholecalciferol replacement mean 25(OH)D3 level was 39,7±10,9 ng/dL (p<0,05). Twenty four (77,4 %) of the patients were on alphacalciferol to control parathyroid hormone. No difference was found in CD4, CD8, CD4 to CD8 ratio, and CD45, serum IL-4, IL-10, interferon-?, pentaxin-3 levels between patients on alphacalciferol and not before and after cholecalciferol replacement (p>0,05). There was no difference in CD3, CD4, CD8, CD4 to CD8 ratio, and CD45, serum IL-4, IL-10, and pentraxin-3 levels after vitamin D replacement, but there was a significant decrease in white blood cell count, IFN-? levels (p < 0.05). Conclusion: In our study replacement with cholecalciferol resulted in decreased levels of the proinflammatory cytokine IFN-? wherease cholecalsiferol therapy could not induce an increase in the serum levels of antiinflammatory cytokines IL-4 and IL- 10. It seems that although there are stimuli that simultaneously may induce generation of many cytokines, each cytokine is derived from a distinct pathway that may be affected differentially by vitamin D.