T and B lymphocytes in patients with pulmonary tuberculosis.

Counts of T and B lymphocytes were made in the peripheral blood from patients with active and inactive pulmonary tuberculosis and in healthy subjects. In patients with active pulmonary tuberculosis the numbers of T cells were significantly lower than in the controls. After treatment for two months, if the patient's condition improved the percentage of T cells returned to nearly normal levels. If the patient failed to improve, the numbers of T cells remained low. The mechanism of these phenomena is discussed.