Morphological Manifestations of Leprosy

Leprosy is probably the best example of a disease that has a spectrum ranging from the anergic to the hypersensitive forms. In tuberculoid form the organised epithelioid cell granulomas are due mainly to the specific cell-mediated immunity. 

Patients with tuberculoid leprosy have localised lesions with scanty organisms and a strong delayed type hypersensitivity against M. leprae which leads to granuloma formation. 

In lepromatous leprosy disseminated skin lesions contain profusely profusely distributed bacilli and show unresponsiveness to M. leprae. This is the field where Modlin et al. (1988) have demonstrated the important concept of investigating the relevant T-lymphocyte subsets of CD45R CD45R ,4B4  

Large numbers of bacilli may invade cutaneous and subcutaneous vessel walk (Coruh and McDougall 1979). If large veins are involved there may be a granulomatous phlebitis with eventual occlusion of the lumen (Mukherjee et al. 1983). 

Neutrophils isolated from leprosy patients release TNF-a and exhibit accelerated apoptosis in vitro (Oliveira et al. 1999). ThaUdomide, a drug known to inhibit TNF-a synthesis on monocytes, exerted an inhibitory effect on TNF-a secretion. 

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