Circulating lymphocyte subsets in second- and third-trimester fetuses: comparison with newborns and adults

Abstract

Objectives: Our objective was to compare the relative sizes of circulating lymphocyte subsets in fetuses, newborns, and adults.

Study design: Two-color flow cytometric analysis of lymphocyte cell surface markers was performed on blood from 64 fetuses, 22 newborns, and 67 normal adults.

Results: All three groups had similar percentages of CD3+ total T cells, CD4+ helper T cells, CD8+ cytotoxic/suppressor T cells, and CD20+ B cells. Compared with adults, fetuses and newborns had markedly reduced percentages of CD57+ natural killer T cells and consistently increased percentages of CD5+CD20+ B cells. Most fetal and cord T and B lymphocytes expressed the activation marker CD38.

Conclusions: Similarities and age-dependent differences exist among fetal, newborn, and adult circulating lymphocyte subsets. Lymphocyte marker analysis may prove useful in the detection of fetal infection and other complications of gestation.