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Anti-HLA antibodies in pediatric renal transplant recipients – Analysis of potential triggers
60
P034
Abstracts / Human Immunology 76 (2015) 38–167
ANTI-HLA ANTIBODIES IN PEDIATRIC RENAL TRANSPLANT RECIPIENTS – ANALYSIS OF POTENTIAL TRIGGERS. Subal K. Pradhan, Martin Bitzan, Lorraine Bell, Chee Loong Saw. McGill University Health Centre, Montreal, QC, Canada. Aim: HLA antigen sensitization poses a challenge both before and after renal transplantation (KTx). Its etiology and clinical importance in pediatric transplant recipients is not well understood. The aim of the study was to examine potential causes of HLA antibody formation in children pre- and post KTx. Methods: A retrospective chart review of pediatric renal allograft recipients ages 1–18 years and transplanted between January 2009 and December 2014 was performed. Data extracted included potential sensitizing events (transfusion, rejection, infection, vaccination) and anti-HLA antibody (Ab) status. Ab were detected by flow cytometry-based single antigen bead assays. A mean fluorescence intensity (MFI) > 1000 was considered positive. Other events such as delayed graft function were not included in the analysis. Results: Of a total of 20 transplanted patients (8 females), 5 received a living-related and 15 a de-ceased donor graft. The median age at KTx was 9.2 years. Eleven of the 20 patients (55%) had detectable HLA Ab during a median follow-up of 3.1 years. Two patients had de-novo donor-specific antibodies (DSA) and two had self-antibodies. Major possible causes of HLA sensitization were blood and platelet transfusions, infections and vaccinations (Table). Mono-specific HLA Ab were identified in 5, multi-specific Ab in 3, and mono- and multi-specific Ab (at discrete occasions) in 3 children. A possible sensitizing immunological trigger was noted in 1 patient with mono-specific, 6 patients with multi-specific, and 1 patient with sequential detection of mono- and multi-specific HLA Ab. Conclusion: Our results demonstrate that transfusions, infections and/or immunizations may sensitize pediatric graft recipients leading to mono- or multi-specific HLA Ab. Their clinical significance, specifically concerning antibody-mediated rejection and graft outcome, remains to be established.
P034
Abstracts / Human Immunology 76 (2015) 38–167
ANTI-HLA ANTIBODIES IN PEDIATRIC RENAL TRANSPLANT RECIPIENTS – ANALYSIS OF POTENTIAL TRIGGERS. Subal K. Pradhan, Martin Bitzan, Lorraine Bell, Chee Loong Saw. McGill University Health Centre, Montreal, QC, Canada. Aim: HLA antigen sensitization poses a challenge both before and after renal transplantation (KTx). Its etiology and clinical importance in pediatric transplant recipients is not well understood. The aim of the study was to examine potential causes of HLA antibody formation in children pre- and post KTx. Methods: A retrospective chart review of pediatric renal allograft recipients ages 1–18 years and transplanted between January 2009 and December 2014 was performed. Data extracted included potential sensitizing events (transfusion, rejection, infection, vaccination) and anti-HLA antibody (Ab) status. Ab were detected by flow cytometry-based single antigen bead assays. A mean fluorescence intensity (MFI) > 1000 was considered positive. Other events such as delayed graft function were not included in the analysis. Results: Of a total of 20 transplanted patients (8 females), 5 received a living-related and 15 a de-ceased donor graft. The median age at KTx was 9.2 years. Eleven of the 20 patients (55%) had detectable HLA Ab during a median follow-up of 3.1 years. Two patients had de-novo donor-specific antibodies (DSA) and two had self-antibodies. Major possible causes of HLA sensitization were blood and platelet transfusions, infections and vaccinations (Table). Mono-specific HLA Ab were identified in 5, multi-specific Ab in 3, and mono- and multi-specific Ab (at discrete occasions) in 3 children. A possible sensitizing immunological trigger was noted in 1 patient with mono-specific, 6 patients with multi-specific, and 1 patient with sequential detection of mono- and multi-specific HLA Ab. Conclusion: Our results demonstrate that transfusions, infections and/or immunizations may sensitize pediatric graft recipients leading to mono- or multi-specific HLA Ab. Their clinical significance, specifically concerning antibody-mediated rejection and graft outcome, remains to be established.