Expression of trophoblast-leukocyte common antigens and placental-type alkaline phosphatase in complete molar pregnancy.

The current study was undertaken to determine the localization of trophoblast-leukocyte common antigens and placental-type alkaline phosphatase in complete molar pregnancy with the use of rabbit antiserum and murine monoclonal antibodies in immunofluorescence assays. Trophoblast-leukocyte common antigens were expressed on all normal villous trophoblast (8 to 38 weeks' gestation) and on all complete moles studied. Placental-type alkaline phosphatase was not expressed on villous trophoblast before 20 weeks' gestation in either normal placentas or complete moles. In contrast, there was strong expression of placental-type alkaline phosphatase on villous trophoblast of normal placentas of more than 20 weeks' gestational age. The expression of polymorphic antigens such as trophoblast-leukocyte common antigens and placental-type alkaline phosphatase on molar trophoblast may be important in the immunobiologic features of gestational trophoblastic disease.