Lymphocyte response after surgery in the neonate.

Fourteen neonates born with congenital malformations were investigated for lymphocyte function before and after surgery. Total leucocyte and absolute lymphocyte counts were unaltered after surgery. The mean percentage of T-lymphocytes observed either pre- or postoperatively was considerably lower than that reported in older children and adults. While there was an increase in the percentage of B-lymphocytes after operation in the infants, the absolute number of B-cells remained unchanges. The preoperative transformation response of lymphocytes to PHA (mean 12.9 +/- 5.4 X 10(3) counts/min) was little different from the postoperative values (mean 12.4 +/- 4.4 X 10(3) counts/min). These results suggest that the neonate is immunologically different from older children and adults in its response to anaesthesia and surgery.