SUN-301 DENOVO DONOR SPECIFIC ANTIBODY AND ITS OUTCOME IN PEDIATRIC RENAL TRANSPLANT RECIPIENTS AT A SINGLE CENTRE IN INDIA

Abstract

Donor specific anti HLA antibody (DSA) is associated with poor graft survival in adults. However there is paucity of data about its prevalence and outcome in Indian children. This study assessed the prevalence and spectrum of DSA and its outcome on allograft function and antibody mediated rejection (ABMR). Children ≤ 18 years who were transplanted between Nov 2016 and June 2019 were included. HLA typing was done for loci A, B, Cw, DQ and DR. Pre-transplant DSA was screened by complement dependent cytotoxicity, flow cytometry crossmatch and single antigen bead (SAB) class I and II by luminex platform. When SAB calss I or II was positive SAB against specific Antigen was done. Either anti thymocyte globulin or basiliximab was used as induction and tacrolimus, mycophenolate and prednisolone for maintenance immunosuppression. SAB assay was done at episode of rejection or at 3, 6 months, 1 and 2 year when graft function was normal. Mean fluorescent intensity ≥ 1000 was considered positive. 15 children, all males with median age 13 years (8, 17) were analyzed. Only one had deceased donor. One child had pre-transplant DSA. Eight (53%) developed denovo DSA. Seven (87%) had Class II, 3 (37%) had Class I and 2 had both. Six had DQ and 2 had DR. DSA developed as early as 1.5 month post-transplant. Seven developed ABMR and all of them had denovo DSA. One of two DSA positive Children with normal graft function had subclinical ABMR. DSAs persisted despite all possible treatment though there was improvement in graft function. However children developing DSA had similar graft function than who did not. Prevalence of denovo DSA was high in our cohort, majority being DQ antibody. HLA typing should include DQ antigen and SAB assay should be done post transplant to identify and treat DSA.