Frequency of Circulating B Cell Subpopulations in Umbilical Cord Blood and Adult Venous Blood

Abstract

Background: The intrauterine and early extrauterine development represents a “window of opportunity” in the immunological development. The underlying mechanisms are still poorly understood. The aim of this study was to provide reference values B cell subpopulations in cord blood of term newborns, juveniles and in adults to find the spectrum of their physiological age-related variation. 
 Methods: In this study, we used flow cytometry to evaluate human B lymphocytes and subpopulations in cord blood (n = 10), in peripheral blood from healthy juveniles aged 1 to 17 years (n=20) and from donors aged 24 to 62 years (n = 10).
 Results: Our findings showed increasing frequencies of IgM memory B cells, class-switched memory B cells, marginal zone B cells and plasmablasts, from cord blood to peripheral blood of juveniles and adults. In con-trast, the percentage of naïve B cells was higher in newborns than in juveniles and adults. The frequencies of were similar in cord blood and peripheral blood of adults. Interestingly, transitional B cells frequencies were similar in cord blood and adults but significantly lower in juveniles.
 Conclusions: The frequencies of circulating B cell subpopulation are subject to considerable changes during on-togeny, reflecting overlying effects of maturation and of the acquisition of an adaptive immune memory.