The Fontan immunophenotype and post-transplant outcomes in children: A multi-institutional study

Area of Science:

• Pediatric Cardiology
• Immunology
• Transplant Surgery

Background:

• Fontan palliation patients are a growing group needing heart transplant (HTx).
• Many Fontan patients exhibit lymphopenia and/or protein-losing enteropathy (PLE), potentially worsening post-transplant outcomes.
• The impact of this altered immune phenotype on HTx is not well understood.

Purpose of the Study:

• To analyze the impact of lymphopenia and PLE on heart transplant outcomes in Fontan patients.
• To evaluate graft survival, infection, rejection, and malignancy rates at 1 and 5 years post-HTx.
• To identify specific risks associated with altered immune phenotypes in this population.

Main Methods:

• Analysis of 106 Fontan patients who underwent HTx between 2005 and 2018 from the Pediatric Heart Transplant Society Registry.
• Categorization of patients based on the presence or absence of lymphopenia (L) and protein-losing enteropathy (PLE): +L+P, +L-P, -L+P, -L-P.
• Assessment of graft survival, infection rates, rejection, and malignancy at 1 and 5 years post-HTx.

Main Results:

• Graft survival was similar across all groups within the first year post-HTx.
• Patients without lymphopenia or PLE (-L-P) had significantly lower infection rates compared to those with either condition (22.1% vs. 41.4%).
• Infection rates per year were significantly lower in the -L-P group (0.3) compared to other groups (1.03-1.3) and similar to non-single ventricle controls (0.4).
• Freedom from rejection and malignancy did not differ among the groups at 1 and 5 years post-HTx.

Conclusions:

• Fontan patients with lymphopenia and/or PLE have an increased risk of infection after heart transplant.
• Despite increased infection risk, these patients show similar early graft survival, rejection, and malignancy rates.
• Findings suggest a need for alternative immunosuppression strategies and enhanced monitoring for this patient subset.