ABSTRACT
The present study has shown that immunohistochemical staining of the human placentas (5 first trimester and 20 full term placentas) for confirmation of the monocytic linease of its macrophage function. We used two macrophage associated glycoprotein; alpha-1-antichymotrypsin (A1Ac) and lysozyme (LSZ). The results from presence or absence of A1Ac & LSZ by immunohistochemical methods can be helpful to deceide the degree of differentiation of macrophage. In al the placentas examined a strong cytoplasmic reaction for A1Ac was seen in the Hofbauer cells, and the same cells of serial sections didn't stain for LSZ. The strong cytoplasmic reaction for A1Ac supports that Hofbauer cells are macrophage, but they didn't stain for LSZ, a bactericidal enzyme, we propose that these cells are not fully differentiated macrophage. The lack of LSZ may have some relevance to the pathogenesis of certain placental infections.