Which occupational lung disease is strongly linked to an increased risk of mycobacterial infection, including tuberculosis?

• A. Asbestosis
• B. Langerhans Cell Histiocytosis
• C. Silicosis
• D. Bronchiectasis

Answer: (C)

Silicosis carries a well-known risk for mycobacterial infections, including tuberculosis, because inhaled crystalline silica directly impairs the function of alveolar macrophages—the cells that are first to respond to inhaled pathogens. Silica particles disrupt phagolysosome formation and intracellular killing, diminishing the ability to kill mycobacteria and allowing TB to take hold or reactivate in silicotic lungs. This macrophage dysfunction creates a niche where mycobacteria can survive and replicate, increasing TB susceptibility in these patients. Among the listed diseases, silicosis is the one most strongly linked to TB risk; the others have different primary associations—asbestosis with asbestos-related malignancies, Langerhans cell histiocytosis with cystic lung changes, and bronchiectasis with recurrent bacterial infections in general but not specifically with mycobacteria.