HIV-1 in trophoblastic and villous Hofbauer cells, and haematological precursors in eight-week fetuses.

AIDS in children is usually caused by vertical transmission of human immunodeficiency virus type 1 (HIV-1). Aborted eight-week fetal and placental tissue from HIV-1 positive and negative (enzyme-linked immunosorbent assay and Western blot) women was analysed by immunocytochemistry and in-situ hybridisation. Maternal decidual leucocytes, villous trophoblastic derivatives, villous mesenchymal cells, and embryonic blood cell precursors in tissues from seropositive patients all stained for HIV-1 antigen and hybridised for nucleic acids. These observations suggest that a cytological pathway for vertical transmission of HIV-1 is established by eight weeks gestational age.