Flow cytometric analysis of lymphocyte subpopulations in infants with congenital heart disease.

Premortem diagnosis of the DiGeorge syndrome and its partial variants relies on the demonstration of a primary defect in cell-mediated immunity, generally in the setting of an infant with congenital heart disease, hypocalcemia, absence of a thymic shadow, and typical dysmorphic features. Although T-cell enumeration is considered a vital part of the diagnostic evaluation, no studies to date have addressed the issue of appropriate reference data in infants with congenital heart disease. We therefore undertook a prospective descriptive study of lymphocyte phenotype analysis in 27 nontransfused infants undergoing diagnostic cardiac catheterization. Striking differences were seen between patients and adult controls in means percentages and numbers of most lymphocyte subsets analyzed. Few differences were found in comparing the patient data to values for age-matched control infants without heart disease. The data are discussed with reference to published values for patients with partial DiGeorge syndrome. It is concluded that lymphocyte phenotype analysis in the diagnostic evaluation of patients with suspected DiGeorge syndrome must utilize appropriate reference values.