Cell-Mediated Immunity in the Newborn: Clinical Aspects

Abstract

The clinical observation that the human newborn infant is uniquely susceptible to certain viral, fungal, protozoan, and bacterial infections has suggested that neonates may have impaired cell-mediated immune function. In order to diagnose primary cellular immunodeficiency during the neonatal period, it is necessary to define carefully normal cell-mediated immunity in term infants, premature infants, and infants with intrauterine growth retardation. CELLULAR IMMUNITY: TERM INFANTS The total lymphocyte count of a newborn infant is greater than 3,000/cu mm. Ferguson1 evaluated 25 healthy term infants (mean birth weight 3,130 gm) as control subjects for a study of children with intrauterine growth retardation. The healthy infants' total lymphocyte counts were 5,101 ± 1,821/cu mm. The subpopulation of lymphocytes that form total E rosettes and thus are defined as thymic derived lymphocytes has been reported as normal or decreased in term infant cord blood. In Ferguson's study, newborn E rosettes were 58% ± 7% in comparison to adult E rosettes of 57% ± 10%. Using comparable methods, four additional studies documented a decreased percent of E-rosette-forming cells in the cord blood of the newborn. The percent of total rosette formation in 13 cord blood samples averaged 33.3% ± 7.6% with a control adult mean in 15 samples of 5l.0% ± 6.5%.2 E rosettes were present in lower proportion in cord blood (53%) than in adult blood (65%) in a study by Campbell et al.3 Smith et al4 reported 53% rosette-forming cells in cord blood samples in contrast to 60% in adult samples. Ben-Zwi et a15 found 50% E-rosette-forming cells in cord blood in contrast to 59% in adult blood.