Importance of the immune response to Mycobacterium leprae in the skin

The causative agent of leprosy is Mycobacterium leprae (M. leprae), which establishes infectious lesions in the skin. Leprosy is classified based on the clinical manifestation, the host’s immune response and skin symptoms. M. leprae is an intracellular pathogen that invades keratinocytes, macrophages, dendritic cells and Schwann cells and replicates within these cells. M. leprae-infected keratinocytes secrete various cytokines and chemokines and induce highly effective immune responses. Understanding the mechanisms by which M. leprae establishes an infection within the skin and the associated immune response may be of great help in the early detection and treatment of the disease.