Lymphocyte Transformation with Mitogens and Antigens during Normal Human Pregnancy: a Longitudinal Study

Abstract

In a longitudinal analysis of immunological changes in normal human pregnancy, twenty‐two pregnant women were studied, with blood samples taken before pregnancy, during its course, at delivery, and 3–5 months after delivery. The blood samples were frozen successively, using a cryobiological freezing system, and were stored until the whole longitudinal series was obtained. The collected material for a longitudinal series was then thawed and tested in one seance. Lymphocyte transformation tests were performed with stimulation with the mitogens phytohae‐magglutinin (PHA), pokeweed mitogen (PWM), concanavalin A (Con A) and the specific antigens tuberculin purified protein derivative (PPD), Candida albicans (CA), Staphylococcus aureus (SA) and streptokinase/streptodornase (SK/SD). No changes were found in PHA or in PWM responses, whereas there were significant changes in the Con A response, with lowest values in the middle of pregnancy. PPD, CA, SA and SK/SD responses all reached lowest values towards the end of pregnancy, with increases subsequently, after delivery. These findings seem to show that T suppressor function is increased and B‐lymphocyte function decreases during the course of pregnancy.