Diminished expression of placental isoferritin p43 component in first trimester abnormal pregnancies

Human placental isoferritin (PLF) is a sub-type of human ferritin mainly co mposed of a 43 kD protein, which has an immunosuppressive activity and may be involved in the downregulation of the maternal immune system during preg nancy. The aim of this study was to evaluate the distribution of p43 in the placental tissue of abnormal first: trimester pregnancies. Samples of vill ous and decidual tissues were collected between 7 and 12 weeks' gestation f rom 28 missed abortions and eight complete moles. Samples of placental tiss ue from 20 normal pregnancies of similar gestational age were used as contr ols. The localization of p43 was determined by immunohistochemical techniqu es using CM-H9 monoclonal antibody. Compared to controls, specific p43 immu noreactivity was low in the villous syncytiotrophoblast of missed abortions and absent from all villous cellular types in complete moles. These findin gs correlate well with the low level of maternal serum PLF found previously in early pregnancy failures and molar gestation. This suggests that PLF ma y be involved in the pathogenesis of early pregnancy disorders related to a n abnormal placentation. (C) 2000 Harcourt Publishers Ltd.