Incidence of Rh immunization following abortion: possible detection of lymphocyte priming to Rh antigen

Anti-autologous erythrocyte plaque-forming cells in pregnancy. A parameter of immunoregulatory change

Peripheral blood leukocytes (PBL) from 16 persons (6 Rh-sensitized pregnant women, 1 pregnant non-Rh-sensitized woman, 3 nonpregnant non-Rh-sensitized women, and 6 non-Rh-sensitized males) were assayed for plaque-forming cells (PFC) against several erythrocyte targets. 6 of 7 pregnant women had PFC, whereas only 1 of 6 males had PFC to autologous red cells. Antiautologous erythrocyte PFC in all of the pregnant Rh-sensitized women as well as the 1 nonpregnant multiparous woman may be the result of alloimmunization of mothers by their fetuses during gestation. Further studies in this area would be valuable in determining not only the immune status of a mother in relation to her fetus, but also would be of value in determining the consequences of that immune status on both mother and fetus. Such information would also provide a further clue to the etiology of autoimmune disease.

Fetal human hemolytic plaque-forming cells. Evidence of reactivity to maternal and other erythrocytes

Lymphoid tissues from 24 human fetuses were assayed for hemolytic plaque-forming cells (PFC) against a variety of erythrocyte targets. PFC against maternal and other erythrocyte antigens were commonly detected in human fetal liver, lymph nodes, spleen, or thymus as early as 16 weeks gestation and were usually more abundant in liver than in spleen after 16 weeks gestation. These data corroborate studies from other laboratories which indicate that human fetuses develop some forms of immunocompetence very early during gestation.