Figure 1.

Mycobacterium tuberculosis (Mtb) infection begins with the recognition and internalization of bacteria by alveolar macrophages, allowing replication and establishment of infection. The immune response involves the secretion of cytokines and chemokines, recruitment of phagocytes, and activation of adaptive immunity, particularly CD4⁺ and CD8⁺ T cells. Monocytes and neutrophils are recruited to the infection site, potentially aiding bacterial dissemination. Dendritic cells play a crucial role in priming adaptive immune responses, presenting Mtb antigens to T cells in lymph nodes. In the lungs and other tissues, granulomas can form. They are a complex immune response mechanism aimed at containing and neutralizing pathogens, and their formation plays a significant role in the pathology of tuberculosis. Dissemination of Mtb from the lungs to extrapulmonary sites can occur through hematogenous spread or direct extension from adjacent lymph nodes or tissues. The immune response in extrapulmonary TB may exhibit variations depending on the involved tissue. Created with Biorender.com (accessed on 7 July 2023).