In mid-2015, we implemented donor-specific antibody (DSA) monitoring in our pediatric kidney transplant recipient (pKTR) population as recommended (Transplantation 2013;95:19-). We now cross-sectionally analyzed our DSA data and, to explore potential predictors of DSA detection in clinically stable (i.e. with no recent fluctuations in T function) pKTRs, collected additional information from the time of DSA testing, including type of immunosuppression [IS, tacrolimus (TAC) vs. sirolimus (SIR)-based], antiproliferative agent dose, variation of the last 3 outpatient IS trough levels, proteinuria (PU, by random protein/creatinine ratio) and calculated glomerular filtration rate (GFR, by Schwartz formula).

A first DSA test was available from 61 pKTRs, 4 of which (all DSA+) had unstable T function (antibody-mediated rejection) and were excluded from further analysis. The characteristics of the other 57 pKTRs are shown

. Initial IS was thymoglobulin induction for Ts from a deceased donor and steroids, TAC and mycophenolate (MMF). Steroids were generally not withdrawn, and TAC and MMF were either converted to SIR and azathioprine (AZA), respectively, for intolerance, or the MMF dose was reduced for apparent MMF-related problems.

The clinically stable pKTRs underwent DSA testing at a median of 2.2 years post-T, and 22/57 (40.4%) were DSA+ (1 class I only, 12 class II only, 9 both). 13/37 (35.1%) pKTRs on TAC and 10/20 (50%, n.s. vs. TAC, Chi-Square) on SIR were DSA+. DSA+ pKTRs were on significantly less MMF [497.5 (n: 13) vs. 704.9 (n:23) mg/sq.m./day, p:0.027 by T-test], had significantly more PU (1.3 vs. 0.44 mg/mg, p:0.025, T-test) and a trend towards worse GFR (63.4 vs. 75.9 ml/min, p:0.056, T-test). We found no significant differences in the number of HLA mismatches, IS trough level variation or other examined parameters.

We conclude that in stable pKTRs, reduced-dose MMF is a risk factor for DSA development and should thus be avoided.

CITATION INFORMATION: Bock M, Starkey L, Buchanan C, Steinberg E, Sikora A, McKinnon K, Wachs M, Goebel J. Donor-Specific Antibodies in a Single-Center Pediatric Kidney Transplant Population – Incidence and Risk Factors. Am J Transplant. 2016;16 (suppl 3).

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