Altered B cell subset distribution and expression of PD-1 in preeclampsia patients

The role of the programmed cell death protein-1/programmed death ligand-1 (PD-1/PD-L1) axis in the pathogenesis of preeclampsia (PE) is currently a subject of research interest. This work aimed to characterize different B cell subsets and their PD-1 expression levels in 54 PE patients compared with 21 age-matched women having normal, uncomplicated pregnancies of comparable gestational age. Also, to evaluate the possibility of a relation between the levels of these subsets with disease severity and the antihypertensive therapy.

B cell subsets were characterized based on the relative expression of CD24 and CD38, and their expression of PD-1 was evaluated in all participants by flow cytometry.

The percentage of naïve B cells decreased significantly, while the percentage of plasmablasts increased significantly in PE patients compared with women having normal pregnancies. PD-1 expression by naïve, transitional, and memory B cells increased substantially in PE patients than in women with normal pregnancies. Naïve B cells had inverse relations with total protein level and positive correlations with systolic and diastolic blood pressure only in the PE patients not receiving antihypertensive therapy.

PE is most probably accompanied by increased B cell activation. The results of the current study point to the critical role played by B cells and PD-1 expressing B cell subsets in PE pathogenesis, progression, and severity. However, the precise impact of PD-1 on B cell activity in pregnant women developing PE necessitates further study.