Incidence, risk factors, management strategies and outcomes of antibody-mediated rejection in pediatric kidney transplant recipients – a multicenter analysis of the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN)

Abstract Background. This study by the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN) was designed to determine the incidence, risk factors, current management strategies and outcomes of antibody-mediated rejection (ABMR) in pediatric kidney transplant recipients (pKTR). Methods. We performed an international, multicenter, longitudinal cohort study of data reported to the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN) registry. 337 pKTR from 21 European centers were analyzed. Clinical outcomes, including renal dysfunction, rejection, HLA donor-specific antibodies, BK polyomavirus-associated (BKPyV) nephropathy, and allograft loss, were assessed through 5 years posttransplant. Results. The cumulative incidence of de novo donor-specific class I HLA antibodies (HLA-DSA) posttransplant was 4.5% in year 1, 8.3% in year 3 and 13% in year 5; the corresponding data for de novo class II HLA-DSA were 10%, 22.5%, and 30.6%, respectively. During 5 years posttransplant, the cumulative incidence of acute ABMR was 10% and that of chronic active ABMR was 5.9%. HLA-DR mismatch and de novo HLA-DSA, especially double positivity for class I and class II HLA-DSA, were significant risk factors for ABMR, whereas cytomegalovirus (CMV) IgG negative recipient and CMV IgG negative donor were associated with a lower risk. BKPyV nephropathy was associated with the highest risk of graft dysfunction, followed by ABMR, T-cell mediated rejection and older donor age. Conclusions. This study provides an estimate of the incidence of de novo HLA-DSA and ABMR in pKTR and highlights the importance of BKPyV nephropathy as a strong risk factor for allograft dysfunction.