Suppression of T-lymphocyte rosettes by rifampin. Studies in normals and patients with tuberculosis.

Studies of circulating T- and B-lymphocyte rosettes were done in 20 healthy controls and 29 patients with pulmonary tuberculosis, including 18 receiving rifampin chemotherapy. Eight of the 18 patients in the rifampin group (44%) had significant suppression of their T-cell rosettes as compared with patients with tuberculosis not receiving rifampin (P less than 0.005). Seven of the eight patients with suppressed T-cell rosettes had received the drug for longer than 6 weeks. No significant difference was observed in circulating T- and B-lymphocyte rosettes between healthy controls and patients not receiving rifampin. Administration of this drug to two healthy subjects in a dosage of 600 mg daily for 28 days was associated with suppression of T-lymphocyte rosettes. The maximum decreases of 40% and 37% were observed at 14 and 21 days respectively, with return to base-line values within 2 weeks of discontinuation of drug therapy; this indicates complete reversibility. Long-term sequential studies will be required to determine whether T-cell suppression after prolonged therapy with rifampin is also reversible or associated with any harmful sequels.