Dynamic Changes in T and B Lymphocyte Subsets Throughout Pregnancy: Establishing Reference Ranges and Clinical Implications.

Background: The immune function of pregnant women undergoes adjustments to meet gestational requirements, which differ from healthy adults. This study aimed to establish reference ranges for lymphocyte subpopulation during pregnancy and explore changes in immune function during different stages of pregnancy.

Method: The participants were divided into the early pregnancy group (143 cases), mid-pregnancy group (42 cases), late pregnancy group (34 cases), postpartum group (3 cases), and postnatal group (10 cases). Peripheral blood T and B lymphocyte subpopulation were detected using flow cytometry, including a total of 25 cell sub¬groups.

Results: There was statistical significance in 7 indicators (naive CD4+ T lymphocytes, central memory CD4+ T lymphocytes, effector memory CD4+ T cells, central memory CD8+ T lymphocytes, CD8+/HLADR+, Th1, and transitional B lymphocytes) among the early pregnancy, mid-pregnancy, and late pregnancy groups. Two indicators (naive CD4+ T lymphocytes and CD8+/HLADR+ T lymphocytes) showed an increasing trend from early pregnancy to late pregnancy, and two indicators (central memory CD4+ T cells and transitional B cells) showed a decreasing trend. Compared to the reference range for healthy adults, four indicators (CD8+ T lymphocytes, CD8+/CD28+ T lymphocytes, effector memory CD8+ T cells and Th2) were higher than those in the normal population and three indicators (Treg cells, naive B lymphocytes, and plasma cells) were lower than those in the normal population.

Conclusion: This study delineates significant changes in T and B lymphocyte subsets during pregnancy, establishing crucial reference ranges. These findings enhance our understanding of immune adaptations in pregnancy, offering valuable data for clinical monitoring and management.