Age-related lymphocyte sub-population changes among healthy Africans from birth to adulthood.

Selected immunological tests were performed on peripheral blood samples obtained from 186 healthy Africans between birth and adulthood. Results are presented by regression analysis. There appeared to be a threshold at 5 years: rate of change of the immunological parameters studied was most rapid between birth and 5 years and least thereafter, with children over 5 years being largely similar to adults. No gender-related differences were detected. In these children, cell numbers are higher and attainment of adult values for T cells earlier than in Caucasians. Formulae are derived from the regression data which allow the prediction of normal values at any age for the parameters studied. This study may serve as a reference for those working in similar environments. The acceleration in development of immunity in black children suggested by these and other results probably indicates early and continual provocation by infections.