Asbestos particles are long, extremely thin, microscopic fibers. When asbestos is in the air, these particles are inhaled by those in close proximity. The fibers are so thin and light that they cannot be properly filtered by the lungs.
The asbestos can become embedded in various parts of the lungs, including the interstitium (the area surrounding the alveoli).
Once embedded, the asbestos particles are attacked by the body’s immune system. Since asbestos is a hard, fibrous mineral, the macrophages are unable to eliminate them from the lungs.
As the macrophages attempt to wipe out the asbestos, they create scar tissue in the area where the asbestos is embedded. As macrophages are unable to remove the asbestos, the body’s immune system sends more and more macrophages, creating more scar tissue.
This creates a chain reaction that cannot be stopped. When scar tissue in the interstitium becomes advanced and there is large-scale injury to tissue of the lung, this is called as “fibrosis”; or, more specifically, “interstitial fibrosis or asbestosis”.
Mycobacterium tuberculosis: Mycobacterium tuberculosis is one of the most ubiquitous pathogen infecting about one-third of the world’s population.
Immune responses to tuberculosis rarely result in complete eradication of the infection.
Instead, TB-infected immune cells promote the generation of chronic inflammation and the formation of granulomas, which are areas where the bacteria are contained but not destroyed.