Developmental changes in lymphocyte surface markers.

The aim of the study was to establish normal values for TG and TM cells in neonates and small babies who are more susceptible to infections than children and adults. For the same reason, the T- and B-lymphocyte ratios were also determined. The percentage of B- and T-cells in neonates was significantly lower, while their absolute number higher, than the adult value. The percentage of TG cells was significantly higher in neonates than in the other age groups. There was a significant decrease in the ratio of TM cells as compared to adult values. Spontaneous thymidine uptake showed an inverse correlation with age, but the difference was not significant. There was a nearly identical response to PHA in the observed age groups, at least to the single dose of PHA applied.