B7 Costimulation and Intracellular Indoleamine‐2,3‐Dioxygenase Expression in Peripheral Blood of Healthy Pregnant and Pre‐Eclamptic Women

Abstract

We determined the frequency of activated (CD11b+) monocytes expressing B7-1, B7-2, B7-H1, and B-7H2, and that of T cells and T helper cells expressing CD28, CTLA-4, PD-1, and ICOS in peripheral blood samples from normal pregnant (NP) and pre-eclamptic (PE) women. We also examined the intracellular expression of indoleamine-2,3-dioxygenase (IDO). We measured the expression of the above markers using flow-cytometry in peripheral blood samples from 20 NP and 20 PE women in the third trimester. The frequency of B7-1 and B7-2 expressing activated monocytes and that of IDO expressing T-lymphocytes was lower in PE than in NP. Lower expression of B7-1 and B7-2 proteins on peripheral monocytes in PE might indicate a secondary regulatory mechanism in response to the ongoing systemic maternal inflammation. IDO plays an important role in the pregnancy-specific immune tolerance, and might be a contributing factor in the pathogenesis of PE.