Renal iron deposition by magnetic resonance imaging in pediatric beta-thalassemia major patients: Relation to renal biomarkers, total body iron and chelation therapy

Background: The reciprocal of multiecho gradient-echo (ME-GRE) T2* magnetic resonance imaging (MRI) R2*, rises linearly with tissue iron concentration in both heart and liver. Little is known about renal iron deposition in beta-thalassemia major (beta-TM). Aim: To assess renal iron overload by MRI and its relation to total body iron and renal function among 50 pediatric patients with beta-TM. Methods: Serum ferritin, serum cystatin C, urinary albumin creatinine ratio (UACR), and urinary beta 2-microglobulin (beta 2 M) were measured with calculation of beta 2 M/albumin ratio. Quantification of liver, heart and kidney iron overload was done by MRI. Results: Serum cystatin C, UACR and urinary beta 2 microglobulin as well as urinary beta 2m/albumin were significantly higher in beta-TM patients than the control group. No significant difference was found as regards renal R2* between Patients with mean serum ferritin above 2500 mu g/L and those with lower serum cutoff. Renal R2* was higher in patients with poor compliance to chelation therapy and positively correlated to indirect bilirubin, LDH, cystatin C and LIC but inversely correlated to cardiac T2*. Conclusion: kidney iron deposition impairs renal glomerular and tubular functions in pediatric patients with beta-TM and is related to hemolysis, total body iron overload and poor compliance to chelation.