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Tuberculosis (TB) has previously been linked to acute respiratory distress syndrome (ARDS). Here this study investigates the link between inflammation and TB in ARDS by measuring inflammatory cytokine and chemokine levels in bronchoalveolar lavage (BAL) from 90 patients with TB or ARDS alone and in patients with TB-induced ARDS (ARDS+TB). BAL was collected by fiber-optic bronchoscopy, and the concentrations of interleukin (IL)-6, CXCL8, TNF α and IL-1β were measured by ELISA. CXCL8 levels in BAL were significantly higher in the ARDS+TB group compared with TB and ARDS alone groups. Disease severity in the ARDS+TB group as determined by Murray score correlated with BAL CXCL8 and neutrophils, but not with IL-6, IL-1β and TNF α concentrations. In addition, CXCL8 levels and neutrophils were increased in non-miliary TB versus miliary TB. This difference in CXCL8 was lost in the presence of ARDS. It was concluded from this study that CXCL8 may play an important role in the pathogenesis of this form of ARDS. This further suggests that CXCL8 inhibitors or blockers may be useful to control the onset and/or development of these combined diseases.

Our understanding of tuberculosis (TB) pathology and immunology has become extensively deeper and more refined since the identification of Mycobacterium tuberculosis (MTB) as the etiologic agent of disease by Dr. Robert Koch in 1882. A great challenge in chronic disease is to understand the complexities, mechanisms, and consequences of host interactions with pathogens. TB, caused by MTB, is a major health problem in world, with 10 million new cases diagnosed each year. Innate immunity is shown playing an important role in the host defense against the MTB, and the first step in this process is recognition of MTB by cells of the innate immune system. Several classes of pattern recognition receptors (PPRs) are involved in the recognition of MTB, including toll-like receptors (TLRs), C-type lectin receptors (CLRs), and nod-like receptors (NLRs). Among the TLR family, TLR1, TLR2, TLR4, and TLR9 and their down streams, proteins play the most prominent roles in the initiation of the immune response against MTB. Beside of TLRs signaling, recently the activation of inflammasome pathway in the pathogenesis of TB much appreciated. Knowledge about these signaling pathways is crucial for understanding the pathophysiology of TB, on one hand, and for the development of novel strategies of vaccination and treatment such as immunotherapy on the other. Given the critical role of TLRs/inflammasome signaling in innate immunity and initiation of the appropriate adaptive response, the regulation of these pathways is likely to be an important determinant of the clinical outcome of MTB infection. In this review paper we focused on the immune response, which is the recognition of MTB by inflammatory innate immune cells following infection.