Role of serum cystatin-C and beta-2 microglobulin as early markers of renal dysfunction in children with beta thalassemia major

Ola Galal Behairy,1 Eman Rateb Abd Almonaem,1 Neveen Tawfik Abed,1 Omima M Abdel Haiea,1 Rasha M Zakaria,1 Rania I AbdEllaty,1 Effat H Asr,1 Amira Ibrahim Mansour,2 Amira MN Abdelrahman,2 Hoda A Elhady3 1Pediatric Department, Benha Faculty of Medicine, Benha University, 2Clinical and Chemical Pathology Department, Benha Faculty of Medicine, Benha University, Benha, 3Clinical Pathology Department, General Organization of Teaching Hospitals and Institutes, Egypt Background: Although advancements have been made in the management of thalassemic patients, many unrecognized complications have emerged, such as renal abnormalities.Aim: To measure serum levels of cystatin-C and β-2 microglobulin in children with beta-thalassemia major (β-TM) and investigate their significance as early markers of glomerular and tubular dysfunctions.Subjects and methods: The study was performed on 70 children with (β-TM) and 20 apparently healthy children matched for age and sex as a control group. For all the enrolled children, a comprehensive medical history was obtained and complete physical examination was performed, blood urea, serum creatinine, serum ferritin, estimated glomerular filtration rate (eGFR) by Schwartz formula and creatinine clearance, albumin/creatinine ratio in urine, serum cystatin-C levels and β-2 microglobulin were measured.Results: Thalassemic children had significantly higher cystatin-C and β-2 microglobulin levels compared with control. In addition, serum cystatin-C and β-2 microglobulin were positively correlated with urea, creatinine, serum ferritin, albumin/creatinine ratio, duration of chelation therapy and frequency of blood transfusion/year and negatively correlated with creatinine clearance, hemoglobin, and eGFR. Our data demonstrated that cystatin-C and β-2 microglobulin had higher sensitivity and specificity (91.4%, 90.0%, and 85.7%, 100%, respectively) than serum creatinine and creatinine clearance (83.0%, 100% and 81.4%, 100%, respectively) for small changes in GFR.Conclusion: Cystatin-C and β-2 microglobulin are specific and sensitive early biomarkers for monitoring glomerular and tubular dysfunction in children with β-TM. Keywords: beta thalassemia, creatinine, sensitivity, specificit