Purpose: Erythropoietin (EPO) is the principal factor regulating red blood cell production in humans. It has been shown that EPO gradually decreases with the progression of diabetic nephropathy and may be used as a marker of severity of disease. In vitro studies have shown that interleukin-10 (IL-10) acts synergistically with EPO to increase stimulation of erythroid differentiation and proliferation. We evaluate serum levels of EPO and IL-10 in children with reflux nephropathy (RN).
Materials and methods: Serum level of EPO and IL-10 were measured in 32 girls and 22 boys with RN, and in 22 boys and 10 girls who served as healthy controls. Renal scarring was evaluated with Technetium dimercapto-succinic acid scan. RN was severe (less than 20% uptake) in 16 children, moderate (20% to 40% uptake) in 25 and mild RN (greater than 40% uptake) in 13. Because anemia may further stimulate EPO production we also compared the index Hb (hemoglobin) x EPO in all patients. IL-10 and EPO were measured with standard enzyme-linked immunosorbent assay technique. The unpaired t test was used for statistical analysis.
Results: There were no statistically significant differences in the serum levels of EPO in children with RN (6.11 +/- 0.51 mIU/ml) compared to controls (6.42 +/- 0.46 mIU/ml) (p >0.5). Similarly the index Hb x EPO was 75.25 +/- 5.65 in children with RN compared to 73.76 +/- 5.48 in controls. Mean EPO levels were similar for mild, moderate and severe RN. There was no difference in the serum levels of IL-10 in children with RN (23.14 +/- 2.32 pg/ml) compared to controls (22.67 +/- 4.13 pg/ml) (p >0.5).
Conclusions: Although EPO has been reported to be a marker of progressive renal disease in diabetic nephropathy, our data indicate that serum levels of EPO do not reflect the severity of renal parenchymal damage in children with RN.