Lymphocyte markers in newborn infants.

Purified peripheral blood lymphocytes from 20 newborn infants and 12 adults have been studied for the presence of surface markers. Adults and infants did not differ in the percentage of sheep RBC-binding cells (means 58-65%) or in Ig-bearing cells measured by the mixed antiglobulin reaction (means 7.2-11.6%). However, newborn infants had a significantly lower percentage of lymphocytes binding Fc of IgG (mean 10.4%) as compared to adults (mean 17.2%). No overall correlation between plasma Ig levels and Ig-bearing lymphocytes was found but a single infant with increased plasma IgA also showed the highest level of Ig-bearing lymphocytes among all infants.