Regulatory T cell frequency and modulation of IFN-gamma and IL-17 in active and latent tuberculosis

Reduced Frequency of Memory T Cells and Increased Th17 Responses in Patients with Active Tuberculosis

“…In this regard, IFN-␥ regulates the development of Th17 cells (14,47), and in TB, this may be a mechanism to control the immunopathology associated with Th17 during mycobacterial infections (14,47,67). Moreover, we and others have previously reported that IL-17-producing cells are less sensitive to Treg-mediated suppression than are IFN-␥-producing cells following stimulation with mycobacterial antigens (4,43). Thus, the change of Th1 toward a nonprotective Th17 profile may exacerbate the inflammation in the lungs by favoring the recruitment of neutrophils.…”

Increased frequencies of pulmonary regulatory T-cells in latentMycobacterium tuberculosisinfection

“…In active TB, the immunological balance fails, inflammation increases and larger numbers of Treg cells are recruited to the site of infection, indicated by higher frequencies of circulating Treg cells [18,19,28,29,36]. Supporting this finding, infected macaques show decreasing numbers of circulating Treg cells during the first weeks following infection, as these are recruited to the lung.…”

“…Their role in active TB has been described but their function during the early and latent stages of M. tuberculosis infection is unknown [18,[27][28][29][30][31]. Although our hypothesis may have been influenced by a potential publication bias because nonsignificant results may not have been published, we postulated that TB contacts with presumed LTBI would differ in the percentage of pulmonary Treg cells compared with non-LTBI contacts.…”

“…Supporting this notion, a pivotal Treg cytokine, transforming growth factor (TGF)-b 1 promotes intracellular growth of M. tuberculosis in vitro [33]. to M. tuberculosis antigens in nearly all studies [18,19,27,28,34,35]. However, in vitro experiments measure an immune response before and after Treg cell arrival in a predefined setting with constant numbers of effector T-cells and mycobacteria.…”

New Diagnostics for Mycobacterium tuberculosis

“…Akin to chronic viral infections, a broad T cell repertoire able to recognise many different types of bacterial epitopes (proteins as well as lipids) enhances the efficiency of the immune response against Mtb (Boom et al, 2003). The balance between different T helper subsets, especially Th1, T (Fox P3+) regulatory cells and Th17 helper cells may also be a key factor (Korn et al, 2007;Liang et al, 2006;Marin et al, 2010;Torrado and Cooper, 2010) and could potentially be explored for diagnostic purposes.…”