T4 lymphopenia in human tuberculosis.

Lymphocyte subpopulations in vitro in 13 patients with bacteriologically-proven tuberculosis and 12 matched controls, by immunofluorescence using monoclonal antibodies have been studied. Active tuberculosis was associated with significant reductions in absolute numbers of total T (Leu 4 or 1+), T4 (Leu 3a+) and B (Leu 12+) lymphocytes, but there were no significant differences in total T8 (Leu 2a+) counts. In two patients, T4-lymphopenia was sufficiently profound to cause reversal of T4: T8 ratio (less than 1.2). These changes were not related to the radiological extent of the disease or size of the Mantoux reaction. Normal ranges for the different classes of lymphocytes were readily restored by chemotherapy.