Immune Abnormalities in Fontan Protein-Losing Enteropathy: A Case-Control Study.

Area of Science:

• Immunology
• Cardiology
• Gastroenterology

Background:

• Protein-losing enteropathy (PLE) is a known complication following Fontan surgery.
• The immunologic consequences of PLE post-Fontan are not fully understood.
• Understanding immune function in these patients is crucial for managing potential complications.

Purpose of the Study:

• To characterize the immune profiles of patients with PLE post-Fontan.
• To compare immune status between patients with and without PLE post-Fontan.
• To identify specific immune abnormalities associated with PLE post-Fontan.

Main Methods:

• Prospective study of 16 patients (8 with PLE, 8 controls) post-Fontan.
• Laboratory assessment of immune function markers.
• Comparison of demographics, cardiac history, immune characteristics, and infection history between groups.

Main Results:

• All patients with PLE had lymphopenia and markedly depressed CD4 T cell counts (median 58 cells/μL) compared to controls (median 450 cells/μL).
• CD4% was significantly lower in the PLE group (12.3%) versus controls (36.9%).
• A majority of PLE patients had negative vaccine titers (measles, mumps, rubella), unlike controls, despite no difference in infection frequency.

Conclusions:

• Patients with Fontan-associated PLE demonstrate significant quantitative immune abnormalities, notably CD4 deficiency.
• These immune deficits resemble those seen in non-Fontan patients with PLE due to intestinal lymphangiectasia.
• The findings underscore the profound immunologic impact of PLE in the context of Fontan circulation.