Populations of peripheral blood lymphocytes in pediatric patients with conotruncal cardiac anomalies

Abstract

Objective - To determine the abundance of principal lymphocyte subpopulations in the peripheral blood of patients with conotruncal cardiac anomalies. Conotruncal cardiac anomalies arise from a developmental defect of the conotruncal septum and often occur as part of 22q11.2 deletion syndrome, also characterized by hypoparathyroidism, growth retardation, characteristic facial dysmorphia and an immune system impairment due to thymic hypoplasia.

Patients and Methods - Deletion of 22q11.2 is detected by fluorescent in situ hybridization in over 90% of patients showing the characteristic phenotype. In these patients, a broad spectrum of immunological defects has been described. Most typical of these is a mild to moderate decrease of T cell number and function. In this study, we determined the numbers of lymphocyte subpopulations (CD3+, CD19+, CD3-CD16/CD56+, CD3+CD4+, CD3+CD8+, CD3+HLA-DR+) in patients treated for conotruncal anomalies (8 patients with 22q11.2 deletion, 7 without 22q11.2 deletion and 4 in whom deletion was not sought) by immunofluorescence/flow cytometry.

Results - The number of patients whose CD3+ cells were decreased in number, as compared to the age-specific reference range, was 4/8, 3/7 and 2/4 in the three groups, respectively (total: 9/19 patients). The remaining lymphocyte subpopulations investigated demonstrated wide variability in all three groups of patients.

Conclusion - This finding is in concurrence with published data and, overall, supports the significance of determining the numbers of lymphocyte subpopulations in all patients with conotruncal anomalies, whether carrying 22q11.2 deletion or not.