Immunohistochemical study of cutaneous neuritis in positive lepromin reactions.

Sixty skin biopsies taken from positive tuberculoid and borderline-tuberculoid late lepromin reaction were studied using histological techniques. The distribution of mycobacterial antigen and nerves was demonstrated using immunochemical methods. A total of 557 nerve bundles was observed in 51 biopsies; 9 were devoid of nerves in the sections examined; 475 nerve bundles showed some relationship to the inflammatory infiltrate (85%); perineuritis being seen in 144 (30%) and endoneuritis in 5 (0.9%). Mycobacterial antigens inside the granuloma were detected in 59 of the 60 biopsies (98%). Only one specimen, showing a strong tuberculoid reaction, failed to show these antigens. On the contrary, mycobacterial antigen was absent in almost all nerves. Small deposits were detected in the perineurium of one nerve with perineuritis, and inside a Schwann cell of another, the latter belonging to a previously multibacillary patient. The neurotropic tendency of the granuloma does not seem to be stimulated by the presence of mycobacterial antigens inside the nerves, as normally these antigens do not penetrate them. The hypothesis of some antigenic fraction of the neural tissue which cross-reacts with Mycobacterium leprae antigens, thus eliciting a perineural or near-perineural inflammatory reaction is put forward, but needs further investigation.

Ultraviolet radiation decreases the granulomatous response to lepromin in humans.

Ultraviolet radiation (UVR) modulates cellular immunity in humans and experimental animals and can interfere with immune responses against infectious agents in animal models. We used the lepromin reaction, a cell-mediated immune response to antigens of Mycobacterium leprae, to determine whether UVR affects the cellular immune response to an infectious agent in humans. We selected 29 healthy, lepromin-positive contacts of leprosy patients and determined their minimal erythema dose (MED) of UVR. Immediately afterward, each subject was injected with 0.1 ml of lepromin in two areas of the buttocks: one at the site that had received twice the MED of UVR and the other on the contralateral, unirradiated site. The irradiated site was given twice the MED every 4 d for a total of five treatments. One week after the last irradiation, both lepromin reactions were measured and biopsied. The size of the lepromin-induced granulomas was significantly reduced in the irradiated site, as was the number of lymphocytes. Immunohistochemical analysis showed a depletion in the number of infiltrating cells and a lower percentage of T cells, particularly the CD4+ subpopulation, in granulomas formed in UV-irradiated skin. This study demonstrates that local UV irradiation reduces the granulomatous reaction to lepromin in sensitized individuals. These findings are of clinical relevance because of the fundamental role played by the delayed-type hypersensitivity response in defense against intracellular pathogens and because of potential increases in the amount of UVR in sunlight reaching the earth's surface.

Leprosy classification for use in control programs.

Some classifications of Leprosy currently in use are reviewed and the difficulties of their application in field work are analysed. While it is recognized the scientific value of these classifications in order to identify precisely the clinical, bacteriological, histological and immunological aspects of the disease, an alternative simplified classification is suggested, to be used in control programmes. In this classification clinical forms that require the same public health action are put together. Thus, clinical forms are reduced to three basic groups. The clinical and laboratory criteria which define each group are presented, as well as the correlation between this simplified classification and the classic one.

Leprosy classification for use in control programs.

Neste trabalho, os autores apresentam uma revisao nos tipos de classificacao de hanseniase, atualmente em uso, alem de uma analise das dificuldades que surgem na sua aplicacao no trabalho de campo. Embora os autores reconhecam o valor cientifico dessas classificacoes, utilizadas para identificar, de modo preciso, os aspectos clinicos, bacteriologicos, histologicos e imunologicos da hanseniase, ao mesmo tempo sugerem uma classificacao mais simplificaca, como alternativa, para ser aplicada em programas de controle. Nesse novo sistema, as formas clinicas, que exigem o mesmo tipo de acao sanitaria publica foram classificadas juntas, sendo reduzidas, portanto, a tres grupos basicos. Os autores apresentam ainda os criterios clinicos e de laboratorio assim como a correlacao entre os sistemas de classificacao simplificado e classico

[Histoid variety of lepromatous leprosy]. / Variedade históide de hansenínase lepromatosa

Three cases of the so-called "histoid variety" of lepromatous leprosy are reported. This variety has definite clinical features, associated with characteristic histological and bacteriological findings. Some of the features presented by our patients are similar to those described originally by Wade, especially the resistance to treatment. Considering the discrepancies existing among the authors that studied the subject, our opinion is that further studies should be done in order to elucidate the controverted points.

The histoid variety of lepromatous leprosy.

Three cases of the so-called "histoid variety" of lepromatous leprosy are reported. This variety has definite clinical features, associated with characteristic histological and bacteriological findings. Some of the features presented by our patients are similar to those described originally by Wade, especially the resistance to treatment. Considering the discrepancies existing among the authors which studied the subject, our opinion is that further studies should be done in order to elucidate the controversial points,