Characteristics of Pulmonary Inflammation in Patients with Different Forms of Active Tuberculosis

Targeted treatment of tuberculosis-associated lung damage requires an understanding of the precise mechanisms of immunopathology. A major obstacle to the longitudinal study of tuberculosis (TB) immunopathogenesis in humans is the lack of serial lung biopsies during disease progression and treatment, which could be used to characterize local immune pathways involved in tissue damage. Understanding of the immunobiology of lung tissue damage in tuberculosis has largely been based on animal models. Our study looked for signs of inflammation in TB patients' lung biopsies. Results were compared between a site of infection and relatively healthy tissue outside the site. The most significant differences in the expression of microRNAs (miRs) and cytokine/chemokines were observed between the non-decayed tuberculoma and the surrounding parenchyma. In addition, these parameters showed almost no differences between the cavitary wall and surrounding tissue. This is an indication that the inflammatory process is more prevalent in fibrotic cavitary tuberculosis (FCT). In FCT subjects, no difference was observed between the cavity wall and the parenchyma in the production of key inflammatory factors such as IL-6, IL-11, IL-17, and IFNγ. This is an indication that the limits of the inflammatory response are broader in FCT. The expression levels of miR-191, miR-193a, miR-222, miR-223, miR-18, miR-155, miR-376c, miR-26a, miR-150, and miR-124 were not significantly different between the cavernous wall and lung tissue in patients with FCT, further confirming the spread of inflammatory and destructive processes beyond the focus of infection.