Leprosy

Leprosy is a granulomatous disease affecting the skin and nerves caused by Mycobacterium leprae. It continues to be a significant public health problem. Despite multidrug therapy, immunologic reactions continue to occur, leading to disability and deformity due to neuropathy. It is important that dermatologists are aware of the neurologic as well as the skin manifestations of the condition so that nerve involvement can be identified and treated rapidly.     

Leprosy

Leprosy is a slowly progressive, chronic infectious disease caused by the bacillus Mycobacterium leprae. It is a very serious, mutilating and stigmatizing disease in many parts of the world and early diagnosis and therapy is the most important strategy for its control. The skin and peripheral nerves are the most affected organs. It is highly infective, but has low pathogenicity and low virulence with a long incubation period. The geographical distribution of leprosy has varied greatly with time and it is now endemic only in tropical and subtropical regions such as India and Brazil. The diagnosis of leprosy is made from the clinical picture, but must be complimented by skin bacilloscopy and histopathology. Leprosy has a number of distinct clinical presentations. Indeterminate leprosy is frequently the initial form consisting of a few lesions that either evolves into the other forms or resolves spontaneously. Lepromatous leprosy is the more contagious form and affects mainly the skin. In addition, some peripheral nerves may be thickened and other symptoms maybe present. The tuberculid form affects the skin and nerves, although usually there are few lesions. There is also a form borderline between the lepromatous and tuberculoid forms. Current treatment of leprosy involves use of 3 drugs: rifampicin (rifampin); clofazimine; and dapsone. Multidrug therapy aims to effectively eliminate M. leprae in the shortest possible time to prevent resistance from occurring. The duration of therapy was recently reduced from 24 to 12 months. Other treatment options are under evaluation in both preclinical and clinical trials and a number show promise. The combination of rifampicin, ofloxacin and minocycline given as a single dose has been recommended for the treatment of paucibacillar leprosy. Only when physicians, other health workers, and the population in endemic countries become fully aware of, and able to recognize, the disease in its initial phase, will it be possible for therapy to be instituted at the very beginning with either the standard scheme or the newer ones. Intervention at such an early stage will avoid the onset of the more serious signs and symptoms, meaning that leprosy will eventually become a less important public health problem. Therefore, efforts must be made to alert populations at risk and all health workers of the importance of an early diagnosis and treatment in leprosy infection.     

Leprosy XII. T-Cell Subsets in Lepromatous Leprosy

ABSTRACT: The authors quantitated T-rosette-forming cell (TRFC) and T-cell subsets (T_μ, T_γ) in the peripheral blood of twenty patients with lepromatous leprosy. The results obtained in their studies are as follows: (1) They reconfirmed the low levels of TRFC in patients with lepromatous type of leprosy; (2) T-cell subsets, both T_μ (helper) and T_γ (suppressor) cells, showed lower levels in all patients with lepromatous leprosy than mean values of normal healthy controls; (3) The degree of decreased levels of T_μ cells (96%) was more severe than other parameters TRFC (70%) and T_γ cells (47%) in all patients with lepromatous leprosy; and (4) it may be concluded that the alteration of the T-cell subset, T_μ-cells, reflects a more fundamental abnormality than TRFC aberration in demonstrating the impairment of cell-mediated immunity in patients with lepromatous leprosy.     

Leprosy.

Growing out of the successful transmission of leprosy to armadillos, making available large quantities of M. leprae, there have been remarkable recent advances in the knowledge of the leprosy bacillus. These bacilli and their isolated chemical constituents provide organisms for in vitro testing of new drugs, reagents for the study of the immunologic dysfunction in leprosy patients, development of early diagnostic methods, and the preparation of candidate vaccines. Leprosy is usually transmitted by the nasorespiratory route, but occasionally, there is transplacental infection. There are reports suggesting that patients have acquired leprosy by contact with wild M. leprae-infected armadillos in Louisiana and Texas. Perturbations in lymphocyte-macrophage interaction appear to be most closely related to the defective CMI in leprosy. The helper T/suppressor T cell populations vary markedly in lesions of the various forms of leprosy, with enhanced suppression of T-cell activity in lepromatous disease. Infiltration of IL-2 and gamma-interferon seems to stimulate CMI in situ in lesions of lepromatous leprosy. Vaccination of lepromatous patients with a killed M. leprae-plus-BCG preparation stimulates CMI and clears tissues of leprosy bacilli, providing an immunotherapeutic approach to the management of leprosy. Immunoprophylactic vaccine trials are in progress, and initial results should be available in 1991. Because of drug resistance, dapsone monotherapy of leprosy is no longer recommended. Multidrug regimens, composed of dapsone, rifampin, and clofazimine or a thioamide, are now required and appear to reduce the incidence of leprosy when applied assiduously. Newer experimental drugs that may eventually be included in these regimens include the fluoroquinolones, minocycline, and clarithromycin. There is no clear evidence that the early serologic diagnosis of leprosy is generally applicable. Favorable response to therapy in multibacillary patients, however, may be assessed by noting drops in levels of M. leprae-specific antigens in blood and urine and, to a lesser extent, levels of specific antibodies in serum. There are conflicting reports on the influence of AIDS on leprosy. There are no convincing data showing that AIDS and leprosy affect each other. Although chemotherapy offers the best current hope for the control of leprosy, effective immunoprophylaxis and improved socioeconomic conditions in endemic areas are thought to be essential in programs for the eradication of leprosy.