Mycobacterium tuberculosis-Induced Reduction of Interferon {gamma}-Producing CD4 T cells in active tuberculosis.

摘要

To the Editor-A recent study by Streitz et al [1] demonstrated a higher frequency of tuberculin-specific CD4 T cells carrying activation markers in peripheral blood of individuals with latent Mycobacterium tuberculosis infection than in those with active pulmonary tuberculosis. As an explanation, the authors suggested that activated T cells may migrate to infected tissues. They left unexplained the fact that more interferon (IFN) gamma-producing T cells (T-helper 1 [Th1] cells) were found in patients with latent M. tuberculosis infection than in those with active pulmonary tuberculosis [1]. Authors of recent studies into the immunopathology of active tuberculosis described 2 main mechanisms for reduced Thl cells in active pulmonary tuberculosis; the main one seems to be an M. tuberculosis-induced increase in immunosuppressive cytokines and in-tracellular mechanisms. One study quantified lung immune mediator gene expression in cells obtained from induced sputum of patients with active pulmonary tuberculosis; compared with controls, these patients had significantly higher levels of mediators that may impair Th1 immunity (interleukin [IL] 10, transforming growth factor-betaRII, interleukin-1 receptor-associated kinase (IRAK)-M, IL-IRn, suppressor of cyto-kine signaling (SOCS) 1, SOCS3, and indoleamine 2,3-dioxygenase (IDO) [2].