Lymphocyte subpopulations in healthy and unhealthy newborn babies.

The Authors report the data of a study of lymphocyte subpopulations (T lymphocytes as rosette forming cells, B lymphocytes as surface immunoglobulin bearing cells, Ea cells as active rosette forming cells, EAC cells, with a receptor for complement, and EA cells, with a receptor for Fc fragment) in venous blood of a group of newborn babies including at term and preterm subjects and babies with and without bacterial infections. A group of healthy adults was also examined as control. Main findings were the following: a) in the group of newborn babies with infection the number of lymphocytes/microliter was higher as compared to that of newborn babies without infections and of adult controls; b) the percentage of T lymphocytes was significantly lower in the two groups of newborn but the absolute number was comparable; c) active rosette forming cells behaved as T lymphocytes; d) absolute number of B lymphocytes was significantly higher in newborn babies with infection as compared to newborn babies without infection and adult controls; e) newborn with infections showed also higher absolute number of EA rosette; f) EAC rosette behaved as T lymphocytes and active rosette forming cells. The increase of B lymphocytes in babies with infection is interpreted as an acceleration of the maturation of lymphocyte populations toward the pattern of older ages. The increase of EA rosette forming cells is tentatively interpreted as an increase of K lymphocytes fostered by infection.