Improved long-term graft function and similar height changes with very low-dose steroid versus late steroid withdrawal in pediatric renal transplantation J. Ferraris1, T.Pasqualini1, G. Alonso1, S. Legal2, P. Sorroche2, A. Galich3, H. Jasper4 1 Departamento de Pediatría, Hospital Italiano de Buenos Aires, Argentina. 2 Laboratorio Central, Hospital Italiano de Buenos Aires, Argentina. 3 Departamento de Medicina Interna, Hospital Italiano de Buenos Aires, Argentina. 4 División de Endocrinología, Hospital de Niños “Ricardo Gutierrez”, Buenos Aires, Argentina. Introduction: Steroid-associated side effects are common after renal transplantation. Since the required steroid dose to achieve optimal immunosuppression is unknown, steroid dosing and subsequent tapering is performed empirically. Moreover, reports of late withdrawal (>6 months) with new immunosuppressive strategies (tacrolimus + mycophenolate mofetil + induction with daclizumab) are not available yet. Furthermore, there are no prospective studies with very low-dose steroids (<0.1 mg/kg/day) and their potential side effects in pediatric renal recipients. Objective: This was a single-centre, concurrent and prospective pilot study whose main objectives were to evaluate and compare: Allograft function, Linear growth, Body composition (by DXA), Lipid profile and Bone mass (by DXA) Two cohorts of patients, both treated with the same immunosuppressive regime but with two different steroid approaches. Material and Methods: Inclusion criteria: Patients who had received a kidney from a living relative-donor (LRD). Pre- or post-pubertal patients. PRA (panel reactive antibodies) levels < 10% No previous episode of acute or chronic rejection, Tacrolimus toxicity or renal artery stenosis. No family history of hyperlipidemia. No history of lipid-lowering pharmacological therapy. Clinical Features of Patients Group 1 Group 2 p Male/female (n) 11/5 11/3 ns Prepuberal (n) 9 7 ns Dysplasia/ Uropathy 7 6 ns Glomerulopathy 6 5 ns Others Etiology 3 3 ns Age at Tx (years) 12.9+6.6 11.5+1.5 ns Age at SW (years) 14.4 +6.6 -- Follow up (years) >3.5 > 3.5 ns Material y Methods: Immunosuppressive Regime Group 1: Late Steroid Withdrawall (LSW) Group 2: Very Low Steroid Dose (VLSD) Main Results: Graft Function: Creatinine Clearance Height Changes in Prepuberal Patients Changes in Body Mass Index 2/9 had Acute Rejection Regional Distribution of Fat Lipid Profile Body Composition (Fat Body Mass) Body Composition (Lean Body Mass) Conclusion: This pilot study provided evidence about two different steroid therapy approaches in pediatric renal transplantation, based on either MP very low-doses or MP late withdrawal. Both steroid strategies allowed similar changes in height, BMD, BMC and preservation of bone-muscle unit. Fat Body Mass decreased only in the group of MP-late withdrawal. The steroid treatment based on MP-late withdrawal showed a disturbing rate of acute rejection and graft function impairment in prepubertal patients. Nonetheless, both steroid strategies allowed a significant increment in height z-score, not seen with standard steroid doses.