Macrophages of human first trimester decidua express markers associated to alternative activation.

Abstract

Depending on the type of their activation, macrophages may promote TH1- or TH2-type of immune responses. To date, not much is known about the activation phenotype of decidua macrophages, which - together with NK cells - constitute the majority of bone marrow derived cells at this location. The study was based on analysis of healthy first trimester decidua by immunohistochemistry and flow cytometry. We analyzed expression of markers characteristic for alternatively activated macrophages (Mphi2). The markers MS-1 (stabilin-1) and coagulation factor XIIIa were found expressed in the interior of decidua macrophages (DMphi). In contrast, indoleamine 2,3-dioxygenase (IDO), an enzyme induced in macrophages by IFNgamma, was not present in DMphi. First trimester DMphi display phenotypic markers associated to alternatively activated macrophages. In addition, absence of IDO indicates that DMphi are not under a predominant influence of IFNgamma.