Quantitative analysis of T and B cell subsets in healthy and sick premature infants.

This work proposes a serial quantitative analysis of the numbers and percentages of B and T cell subsets in 104 consecutive premature infants (PI) between birth and six months of age as compared with 21 normal term infants. First, in order to ascertain the effects of perinatal distress at birth (respiratory distress, neonatal asphyxia) on certain parameters of the immune system, the PI were divided into two groups. One comprised 36 healthy preterms, the other, 68 preterms with perinatal distress. It was then shown that healthy PI differed from full-term infants by their higher absolute numbers of T cells (CD2-positive) and helper T cell subset (CD4-positive). These increases in CD2- and CD4-positive cells correlated with gestational age (GA). An increase in B lymphocytes (CD20-positive cells) was also documented but no correlation with GA could be seen. Secondly, perinatal distress was found to be concomitant with transient decrease in percentages and absolute numbers of CD2- and CD4-positive cells, particularly in PI of less than 28 weeks of gestation. The B cells (CD20- and CD21-positive cells) were not different in absolute numbers. Respiratory distress had a more discernable effect than fetal asphyxia on the immune system. Finally, no immunological parameters tested could at any time predict the occurrence of infection in PI during the first 6 months of life.