Molecular Pathogenesis of Leprosy

Leprosy is a chronic infectious granulomatous disease caused by the obligate intracellular bacteria Mycobacterium leprae. M. leprae causes symptoms in the skin, peripheral nerves, and other tissues. Type 1 (reversal reaction) and type 2 (erythema nodosum leprosum) lepra reactions are the main mechanisms of skin lesions, nerve damage, and other types of tissue damages. Susceptibility to mycobacterial infection and the clinical presentations of the disease are associated with aberrant host immune response, which forms the spectrum and pathologic manifestations of the disease.