Human leukocyte antigen sensitization in pediatric patients exposed to mechanical circulatory support
Borah J Hong1, Meghan Delaney, Anthony Guynes
1From the *Division of Pediatric Cardiology, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas; †Puget Sound Blood Center, Seattle, Washington; ‡University of Washington School of Medicine, Seattle, Washington; §Division of Pediatric Cardiothoracic Surgery, Seattle Children's Hospital, University of Washington, Seattle, Washington; and ¶Division of Pediatric Cardiology, Seattle Children's Hospital, University of Washington, Seattle, Washington.
Insights
Pediatric heart transplant candidates on mechanical circulatory support (MCS) have a low risk of developing human leukocyte antigen (HLA) sensitization. Older age and homograft history may be associated risk factors.
Area of Science:
- Immunology
- Pediatric Cardiology
- Transplantation Science
Background:
- Human leukocyte antigen (HLA) sensitization poses a significant risk for rejection and graft loss in pediatric heart recipients.
- Mechanical circulatory support (MCS) is increasingly used in children as a bridge to heart transplantation.
- Understanding risk factors for HLA sensitization in pediatric MCS patients is crucial.
Purpose of the Study:
- To investigate the incidence and risk factors for human leukocyte antigen (HLA) sensitization in pediatric patients supported with mechanical circulatory support (MCS).
Main Methods:
- A single-center retrospective review was conducted on 36 pediatric patients who received MCS (extracorporeal membrane oxygenation [ECMO] or ECMO-ventricular assist device [VAD]).
- Paired pre-MCS and post-MCS panel reactive antibody (PRA) data were analyzed.
- Multivariable analysis was used to identify associations between sensitization and patient characteristics.
Main Results:
- Four patients (18%) developed HLA sensitization post-MCS.
- No significant differences were found in diagnosis (congenital heart disease vs. cardiomyopathy), MCS duration, or blood product transfusion volume between sensitized and non-sensitized groups.
- Older age at MCS and a history of homograft transplantation approached statistical significance as potential risk factors for sensitization.
Conclusions:
- Pediatric patients supported with MCS demonstrate a low risk of developing HLA sensitization.
- Factors such as diagnosis, MCS duration, and transfusion volume do not appear to be strongly associated with sensitization.
- Older age and prior homograft exposure may warrant further investigation as potential contributors to HLA sensitization in this population.
Abstract:
Human leukocyte antigen (HLA) sensitization of pediatric heart recipients increases their risk of rejection and graft loss. As more children are placed on mechanical circulatory support (MCS) as a bridge to transplant, the risk factors for development of sensitization warrant further study. A single-center retrospective review of 36 children who received MCS identified 22 patients supported with either extracorporeal membrane oxygenation (ECMO) (n = 15) or ECMO-ventricular assist device (VAD) (n = 7) with paired (pre-MCS/post-MCS) panel reactive antibodies (PRA) or only negative post-MCS PRAs. Four patients (18%) became sensitized post-MCS (one ECMO-only patient, three ECMO-VAD patients). No difference was found between sensitized and nonsensitized patients in terms of congenital heart disease versus primary cardiomyopathy (p = 0.096), duration of MCS (38 days vs. 14 days, p = 0.233), or volume of blood product transfusions (358.6 ml/kg vs. 612.7 ml/kg, p = not significant). By multivariable analysis, the association of sensitization with older age at MCS (p = 0.076) and history of homograft (p = 0.064) approached significance. Pediatric patients supported with MCS are at low risk of developing HLA sensitization. Diagnosis, MCS duration, and volume of transfused blood products do not appear to be associated with HLA sensitization, but there is a suggestion of an association with older age at MCS and history of a homograft.
