A prospective study of the incidence, time of appearance and significance of anti-paternal lymphocytotoxic antibodies in human pregnancy.

The incidence and natural history of serum anti-paternal cytotoxic antibody (APCA) in normal pregnancy and spontaneous abortion was investigated prospectively in 306 women (64 primigravidae and 242 multigravidae), in order to establish whether serum APCA is a useful screening test in the diagnosis, treatment and prognosis for patients with recurrent pregnancy loss. Pre-pregnancy, serial pregnancy and post delivery serum samples were tested against partner's lymphocytes, using a microdroplet lymphocytotoxicity assay. The incidence of serum APCA in the 256 pregnancies successfully completed was 32%, compared with 10% amongst the 50 pregnancies ending in spontaneous abortion. The lower incidence of positive APCA tests in unsuccessful pregnancies was explained by our finding that positive APCA tests are related to the gestational age of the pregnancy and are rarely demonstrable before 28 weeks gestation. Since APCA usually disappears between pregnancies, its usefulness as a diagnostic test for immunotherapy against recurrent abortion should be questioned.