Localization of leukocytes and cytokines in chorionic villi of normal placentas and complete hydatidiform moles

Monoclonal antibodies were used to localize and characterize leukocytes and cytokines in chorionic villi of normal placenta and complete mole. OKT4a reacted with Hofbauer cells in first-, second-, and third-trimester placentas. HLA-DR was expressed on second- and third-trimester placental Hofbauer cells but was not detected in the first trimester. The cytokines, gamma-interferon, granulocyte-macrophage colony-stimulating factor, interleukin-1 alpha, and tumor necrosis factor alpha, were all detectable on Hofbauer cells in first-, second-, and third-trimester placentas. None of the tested cytokine antibodies reacted with cellular constituents in complete molar chorionic villi. The absence of cytokine-positive cells in molar chorionic villi may be related to the hyperplastic and unregulated growth of molar villous trophoblast.