Immune Abnormalities in Patients With Single Ventricle Circulation Precede the Fontan Procedure

Background:Immune abnormalities are common in Fontan patients with protein-losing enteropathy. Limited data exist on immune function of other patients with single ventricle circulation.Methods:This prospective cohort study evaluated immunologic characteristics of children with single ventricle circulation from neonatal age up to early post-Fontan period.Results:Low leukocyte counts were observed in half of the patients prior to bidirectional Glenn and Fontan surgery. Total lymphocyte counts were below normal range in 36% to 63% of patients across all groups except patients following Fontan procedure who had normal counts. Typical lymphocyte subpopulation patterns were (1) high counts of total and helper T lymphocytes (CD3+ and CD4+ cells), low B lymphocytes (CD19+ cells), and increased CD4/CD8 ratio in neonates and (2) low T lymphocytes (CD3+, CD4+, CD8+ cells) with high natural killer cells (CD16+) and B lymphocytes (CD19+ cells) in other groups. Low preoperative total lymphocyte counts were associated w...