RESUMO
New tools for the detection of leprosy exposure in a community will be necessary for the eradication of leprosy. Candidate leprosy skin-test antigens derived from the fractionation of the leprosy bacillus into cytoplasmic and cell-wall proteins free of immuno-inhibitory mycobacterial lipoglycans and carbohydrates were used in an overnight blood test to determine whether exposure to leprosy can be detected by the production of the cytokine interferon gamma (IFN-gamma). Strong IFN-gamma responses were detected in leprosy contacts to both skin-test antigens compared with control subjects from the same endemic communities. There was little response in patients with tuberculosis. Responses were greatest in contacts with recent leprosy exposure. The implications of these findings for the application of these reagents in a field trial as skin tests to detect exposure to leprosy are discussed in light of the strong association between overnight IFN-gamma to PPD and the tuberculin skin-test responses previously reported.
Assuntos
Hanseníase/genética , Hanseníase/imunologia , Interferon gama/farmacologia , Interferon gama/uso terapêuticoAssuntos
Antígenos HLA-DR/genética , Antígenos HLA-DR/metabolismo , Antígenos de Bactérias/genética , Antígenos de Bactérias/imunologia , Ativação Linfocitária , Dados de Sequência Molecular , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/química , Especificidade da Espécie , Genoma Bacteriano , Hanseníase Tuberculoide/diagnóstico , Hanseníase Tuberculoide/imunologia , Hanseníase Tuberculoide/microbiologia , Linfócitos T/imunologia , Mycobacterium leprae/genética , Mycobacterium leprae/imunologia , Mycobacterium leprae/química , Peptídeos/imunologia , Peptídeos/síntese química , Sequência de AminoácidosRESUMO
A retrospective study of new borderline lepromatous and lepromatous patients reporting for multidrug therapy (MDT) for leprosy at the Anandaban Leprosy Hospital, Kathmandu, Nepal, over an 8-year period was conducted to determine the prevalence of erythema nodosum leprosum (ENL), the time and frequency of reactions, and clinical and laboratory parameters associated with ENL. An overall prevalence of ENL in this cohort of 19% was found. One third of these reactions occurred in patients before MDT was given, one third in the first 6 months and one third after 6 months of treatment. Nearly 1 in 10 of the ENL reactions occurred in patients who had completed 2 years of MDT; 45% of patients with ENL had more than one episode. Data collected at the patients' first presentation was used to identify four major risk factors. Patients with lepromatous disease, skin infiltration or a bacterial index (BI) of > 4+ were at significantly increased risk. Patients older than 40 were at significantly decreased risk of ENL. There was a linear relationship in the risk of ENL with an increasing BI and an inverse relationship to increasing age. These observations should enable clinicians to recognize patients at first presentation who will be likely to develop ENL.