An analysis of in vitro T cell responsiveness in nontuberculous mycobacterial infection

In vitro cell-mediated immunity was examined in patients infected with nontuberculous mycobacteria, Mycobacterium avium-intracellulare complex in Japan. Peripheral blood lymphocytes of patients, as compared with those of tuberculous patients or tuberculin-positive healthy donors, showed depressed in vitro blastogenic responses to purified protein derivative of tuberculin (PPD), not only to PPDs of Mycobacterium tuberculosis but also to PPD-B and PPD-Y of M intracellulare and M kansasii, respectively. Nonspecific lymphocyte blastogenic responses to concanavalin A, phytohemagglutinin and pokeweed mitogen were normal. Analysis of defective in vitro PPD-induced lymphocyte blastogenic responses in these patients revealed that PPD-induced interleukin 2 (IL-2) production was impaired whereas PPD-induced IL-2 responsiveness was normally developed after PPD stimulation. Therefore, addition of exogenous recombinant human IL 2 substantially recovered the in vitro depressed PPD-induced blastogenic responses in these patients with nontuberculous mycobacterial infection.