Immunologic and medical considerations in tuberculin-sensitized pregnant patients.

One-hundred and seventy-two pregnant patients were identified as tuberculin sensitive in the first trimester. These patients were followed throughout pregnancy for any signs or symptoms of active tuberculosis which were discovered only in the index case. Post partum, patients were again re-evaluated for tuberculosis and prophylactically treated with isoniazid if they met established criteria. The tuberculous host also represented a model for the study of cell-mediated immunity, which presumably is altered in pregnancy. This investigation revealed a progressive depression of lymphocyte function to a specific antigen, purified protein derivative, obtaining significance at 36 weeks' gestation and continuing through delivery (p is less than 0.001). Nonspecific cell-mediated immunity, however, was not depressed when monitored throughout the gestation by the mitogen, phytohemagglutinin, which would stimulate all lymphocyte clones. This discrepancy in the alteration of specific clones of lymphocytes compared to all noncommitted lymphocytes may account for varying reports of the immune status of the pregnant woman.