Immunocytochemical HBsAg evidence in placentas of asymptomatic carrier mothers.

We report three chronic asymptomatic HBsAg carrier mothers. We studied their placentas via application of the immunohistochemical method to identify HBsAg by peroxidase-antiperoxidase techniques. All three placental specimens showed a positive HBsAg reaction. Due to the strong cytoplasmatic reactivity of the cytotypes, we deduced their active participation in the infection, proving that virosis occurs via transplacental circulation.