[The influence of pregnancy on the immunologic reactivity of the mother. Investigations into the reactivity of the peripheral lymphocytes to mitogens and on the percentage rate of B-cells in the maternal blood during pregnancy (author's transl)].

In pregnant women, lymphocytes from the peripheral blood were stimulated with phytohemagglutin (PHA), pokeweed mitogen (PWM) and Concanavalin A (CON A) and the percentage rate of B-cells was determined. Compared to healthy non-pregnant controls of the same age, no significant difference in the stimulation or the percentage of B-cells was found at different times of pregnancy. The observation of other authors was confirmed that phytohemagglutin induced stimulation of lymphocytes in non-pregnant controls can be diminished by the addition of pregnant serum instead of the normally used homologus AB serums. Our results lead to the conjecture that the diminished reactivity of the maternal lymphocytes during pregnancy is not intrinsic to the lymphocyte in pregnancy but more likely due to inhibitory substances in the serum of the pregnant patient.