Immunohistochemical detection ofterminal complementcomplex andSprotein innormalandpre-eclamptic placentae

SUMMARY Terminal complement complex andSprotein were searched forintermplacentae obtained from13 women withnormal pregnancy and15patients withmoderate or severeformofpre-eclampsia. Terminal complement complex was found tolocalize inthefibrinoid material ofthedecidua ofthe basal plate, inthestromaofthechorionic villi andinthevessel walls, assubendothelial deposits. S protein hadaquite different distribution, being detected inthesyncytiotrophoblast located bothin thechorionic villi andinthedecidua ofthebasal plate (DBP)andalso on theendothelial cells offetal stemvessels. Milddeposits ofC3werefound inthedecidua ofthebasal plate andalso inthestroma andon thebasal membranes ofthevilli. Reactivity forC9neoantigen was alsoobserved inthe cytoplasm ofsome cells, which wererecognized tobemacrophages bythe presenceintheir cytoplasm ofacidphosphatase andbytheir reaction witha monoclonal antibody specific formacrophages. Differences incomplement deposition innormalandpre-eclamptic placentae were essentially quantitative. Possible mechanisms ofcomplement activation arediscussed.