Fibrosis: a distinguishing feature in the pathology of neural leprosy

BACKGROUND Fibrosis in the peripheral nerve is the end stage of leprous neuropathy and the cause of the resulting permanent neural function impairments. Preventive measures to avoid this irreversible pathological state are a relief strategy for leprosy sufferers. OBJECTIVES The present study describes the frequency of fibrosis along with its characterisation and pathogenic development. METHODS Six-hundred-and-thirteen nerve samples were sorted from 278 neural leprosy (NL) and 335 non-leprosy neuropathy patients (ON). The total number of samples was histologically examined by routine staining methods (haematoxylin-eosin, Wade staining and Gomori's trichrome) and fibrosis was evaluated via semi-quantitative estimation. FINDINGS Fibrosis was most frequent in the NL group (33% against 0.4% in ON) while fibrosis in association with endoneurial microfasciculation was found in 38 (41.3%) of the NL samples in the examination of semithin sections. Pericytic activation in the perivascular environment was confirmed to be the source of the fibroblasts and perineurial cells delimiting microfascicles. End-stage fibrosis in leprosy displays an arrangement of microfascicles devoid of neural components (i.e., Schwann cells and axons) lined by an intermediate phenotype of fibroblastic-perineurial cells filled with bundles of collagen fibres. MAIN CONCLUSIONS The present study underscores that fibrosis is frequently the severe end stage of neural leprosy NL pathogeny after analysing the notably distinct development of fibrosis within the neural environment.

Percepción de la lepra y las discapacidades antes del diagnóstico en Recife, Brasil / Perceptions regarding leprosy and resulting handicaps prior to diagnosis in Recife, Brazil

Este artículo presenta un estudio de casos y controles realizado en Recife, Brasil, entre noviembre de 1993 y julio de 1994. En él se investigó cómo influyen la percepción y las apreciaciones de los propios pacientes de lepra en el proceso de manejar la enfermedad y en la utilización de los servicios de salud. La muestra estuvo constituida por 183 pacientes de 20 a 70 años de edad, residentes en Recife, que acudieron en busca de un diagnóstico a los servicios de dermatología sanitaria de dos centros de referencia de las regiones politicoadministrativas tercera, cuarta y sexta. Se clasificaron como casos los 64 pacientes que tenían discapacidades o lesiones precursoras de discapacidad; los 119 restantes se consideraron controles. Todos fueron diagnosticados durante el período de la investigación. En el análisis se ajustó según sexo, edad, escolaridad y antecedentes de la enfermedad de Hansen de los pacientes. El estudio reveló la coexistencia de dos tipos de "invisibilidad" de la enfermedad en una zona endémica en expansión: 1) para los pacientes de ambos grupos, la baja frecuencia de modelos explicativos, espontáneos, relacionados con la dolencia, aun en presencia de antecedentes de la enfermedad, y 2) para los profesionales sanitarios, las limitaciones de la detección. Puesto que afectan a las decisiones relacionadas con el manejo individual y colectivo de la enfermedad, esas deficiencias constituyen por sí mismas un factor de riesgo y representan un obstáculo para la eliminación de la lepra como problema de salud pública.

This article reports on a case-control study conducted in Recife, Brazil, between November 1993 and July 1994, to determine how leprosy patients' perceptions and notions influence disease management and use of health services. The sample was composed of 183 residents of Recife between the ages of 20 and 70 years who sought diagnostic services in the dermatology clinics of two referral centers situated in the third, fourth, and sixth political and administrative regions. Sixty-four patients having handicaps or their precursor lesions were classified as cases; the remaining 119 were used as controls. All were diagnosed during the study period. For the analysis, adjustments were made for sex, age, schooling, and a previous history of Hansen's disease among patients. The study revealed the simultaneous presence of two types of "invisibility" of the disease in an area where endemicity is increasing: 1) for patients in both groups, the low frequency of spontaneous explanatory models related to the illness, even in the presence of disease, and 2) for health professionals, the limitations of detection methods. Since such deficiencies affect decisions bearing on individual and collective disease management, they are a risk factor in and of themselves and stand in the way of eliminating leprosy as a public health problem.

T-cell response to my mycobacterial antigens in lepromatous and tuberculoid leprosy

We showed that a large fraction of lepromatous patients do harbor helper-type circulating T-cells that can be activated in vitro by Mycobacterium leprae. M. leprae and PPD triggered T-cell lines could be then obtained from both tuberculoid and lepromatous patients. The proliferative response of these helper T-cells is predominantly directed against epitopes shared by several species of mycobacteria, in lepromatous patients as well as in tuberculoid patients, but species specific T-cells are also present. When presented in the context of M. leprae, these cross reactive epitopes usually fail to stimulate the T-cell lines of lepromatous patients, because of the contamination of the lines by supressor T-cells actavable by M. leprae. In one lepromatous patient, PPD and M. leprae reactive T-cell lines and clones (of the CD4 phenotype), exhibited a strong cytotoxic activity to autologous target cells coated with antigen: the relevance of this phenomenon to the pathophysiology of lepromatous leprosy remains however unknown.