Quantitation of T cells in venous blood of healthy neonates.

Quantitation of T Cells in blood is the part of the diagnostic workup for cellular immunity. Specimens of venous blood were collected within 24 hours of birth from 51 healthy, appropriate for gestational age infants. T lymphocytes were identified on the basis of their ability to form rosettes with sheep erythrocytes. The lymphocytes were harvested from peripheral venous blood, which is considered to be more representative of the immune status in the newborn than the cord blood. In the newborn infants the proportion in T cells was found to be considerably diminished in comparison to previously reported values for adults. Preterm infants, especially those with gestational age of 34 wk or less had significantly lower percentage of T cells in their blood as compared with term infants. The proportion of T cells was statistically reduced in infants weighing 2000 g or less in contrast to those weighing 2500 g or more.