New Insight into the Pathogenesis of Erythema Nodosum Leprosum: The Role of Activated Memory T-Cells.

Memory T-cells, particularly, effector memory T cells are implicated in the pathogenesis of inflammatory diseases and may contribute to tissue injury and disease progression. Although erythema nodosum leprosum (ENL) is an inflammatory complication of leprosy, the role of memory T cell subsets has never been studied in this patient group. The aim of this study was at investigate the kinetics of memory T cell subsets in patients with ENL before and after prednisolone treatment. A case-control study design was used to recruit 35 untreated patients with ENL and 25 non-reactional lepromatous leprosy (LL) patient controls at ALERT Hospital, Ethiopia. Venous blood samples were obtained before, during, and after treatment from each patient. Peripheral blood mononuclear cells (PBMCs) were isolated and used for immunophenotyping of T cell activation and memory T-cell subsets by flow cytometry. The kinetics of these immune cells in patients with ENL before and after treatment were compared with LL patient controls as well as within ENL cases at different time points. The median percentage of CD3+, CD4+, and CD8+ T-cells expressing activated T-cells were significantly higher in the PBMCs from patients with ENL than from LL patient controls before treatment. The median percentage of central and activated memory T-cells was significantly increased in patients with ENL compared to LL patient controls before treatment. Interestingly, patients with ENL had a lower percentage of naïve T cells (27.7%) compared to LL patient controls (59.5%) (P < 0.0001) before treatment. However, after prednisolone treatment, patients with ENL had a higher median percentage of naïve T-cells (43.0%) than LL controls (33.0%) (P < 0.001). The median percentage of activated T-cells (effector memory and effector T-cells) was significantly increased in patients with ENL (59.2%) before treatment compared to after treatment with prednisolone (33.9%) (P < 0.005). This is the first work which has shown T-cell activation and the different subsets of memory T cells in untreated patients with ENL. Consequently, this study delineates the role of T-cell activation in the pathogenesis of ENL reaction and challenges the long-standing dogma of immune complex as a sole etiology of ENL reaction

RECIDIVA NA DOENÇA DE HANSEN - ESTUDO RETROSPECTIVO E DESCRITIVO DE 5 ANOS

Introduction: Relapse of Hansen's disease refers to the appearance of new signs and symptoms in patients with a previous diagnosis and who completed the treatment regimen proposed by WHO.Objectives: To determine and characterize relapse cases of Hansen's disease within five years (2008-2012), in Hansen's disease consultation from Hospital Curry Cabral.Material and Methods: We conducted a retrospective and descriptive review of clinical records, identifying cases in a total of 89 patients seen in consultation in that period. The minimum follow-up time was 6 months. In all cases, clinical suspicion of relapse was confirmed by bacteriological and histopathological examination.Results: We identified 4 cases of relapse, which corresponded to 4.5% of patients observed, all with a previous diagnosis of borderline lepromatous clinical form, according to the Ridley-Jopling classification. Therapy has been established for multibacillar forms according to WHO scheme in all cases. Relapses occurred in a follow-up period between 7 and 16 months after treatment discontinuation.Discussion: The frequency of relapse in this population was higher than that observed in most studies. There was poor adherence to therapy in all cases, admitted as the cause of relapse, after excluded other factors. We emphasize the importance of regular monitoring of patients undergoing treatment, to ensure adherence and effectiveness of therapy.Introdução: A recidiva na doença de Hansen refere-se ao aparecimento de novos sinais e sintomas em doentes com diagnóstico prévio e que completaram o esquema de tratamento proposto pela OMS.Objectivos: Determinar e caracterizar os casos de recidiva da doença de Hansen num período de 5 anos (2008-2012), na consulta de doença de Hansen do Hospital Curry Cabral.Material e Métodos: Realizou-se um estudo retrospectivo e descritivo, através da consulta dos processos clínicos, com identificação dos casos num total de 89 doentes observados na consulta no referido período. O tempo mínimo de seguimento foi de 6 meses. Em todos os casos, a suspeita clínica de recidiva foi confirmada por baciloscopias e exame histopatológico.Resultados: Foram identificados 4 casos de recidiva, o que correspondeu a 4,5% do total dos doentes observados, todos com diagnóstico prévio da forma clínica borderline lepromatosa, de acordo com a classificação de Ridley-Jopling. Foi instituída terapêutica para as formas multibacilares de acordo com esquema OMS em todos os casos. As recidivas ocorreram num período de seguimento entre 7 e 16 meses após interrupção do tratamento.Discussão: A frequência da recidiva da doença na população de doentes foi superior à observada na maioria dos estudos. Verificou-se incumprimento da terapêutica em todos os doentes, admitida como causa de recidiva, excluídos outros factores. Destacamos a importância do acompanhamento regular dos doentes em tratamento, permitindo assegurar a adesão à terapêutica e a sua eficácia

In search of biomarkers for leprosy by unraveling the host immune response to Mycobacterium leprae

Mycobacterium leprae, the causative agent of leprosy, is still actively transmitted in endemic areas reflected by the fairly stable number of new cases detected each year. Recognizing the signs and symptoms of leprosy is challenging, especially at an early stage. Improved diagnostic tools, based on sensitive and specific biomarkers, that facilitate diagnosis of leprosy are therefore urgently needed. In this review, we address the challenges that leprosy biomarker research is facing by reviewing cell types reported to be involved in host immunity to M leprae. These cell types can be associated with different possible fates of M leprae infection being either protective immunity, or pathogenic immune responses inducing nerve damage. Unraveling these responses will facilitate the search for biomarkers. Implications for further studies to disentangle the complex interplay between host responses that lead to leprosy disease are discussed, providing leads for the identification of new biomarkers to improve leprosy diagnostics.Immunogenetics and cellular immunology of bacterial infectious disease

The immunopathology of erythema nodosum leprosum

Leprosy is a disease caused by Mycobacterium leprae, an acid-fast bacillus whose clinical spectrum correlates with the host immune response. Erythema nodosum leprosum (ENL) is an immune-mediated inflammatory complication causing high morbidity in affected leprosy patients. A case-control follow-up study was conducted in Ethiopia to test the hypothesis that ENL is associated with impaired immune regulation. In 46 patients with ENL and 31 lepromatous leprosy (LL) matched controls, the frequency of regulatory T-cells, memory T-cells and B-cells were analysed by flow cytometry. The in vitro pro-inflammatory cytokines production by peripheral blood mononuclear cells (PBMCs) to the response of M. leprae whole cell sonicate stimulation was determined by Enzyme-linked immunosorbent assay. The gene expression of these cytokines in the blood and skin biopsies was determined by quantitative polymerase chain reaction (qPCR) before and after treatment. Patients with ENL had lower percentage of CD4+ regulatory T-cells than LL controls at recruitment. The percentage of CD3+, CD4+ and CD8+ T-cells expressing activated T-cells were significantly higher in the PBMCs of patients with ENL than in LL controls before treatment. The in vitro production and gene expression of the cytokines: TNF-α, IFN-γ, IL-1β, IL-6, IL-8 and IL-17A were significantly increased in untreated patients with ENL. ENL patients had a higher median percentage of tissue-like memory (TLM) and activated memory (AM) B-cells than LL controls before treatment while the median percentage of total B-cells and resting memory (RM) B-cells did not significantly different in both groups before treatment. The level of anti-PGL-1, LAM and Ag85 antibodies were not significantly different in patients with ENL before treatment. Patients with ENL had significantly lower circulating C1q than LL controls before treatment. However, after treatment, the amount of circulating C1q was not significantly different in both groups. Our findings suggest that ENL is associated with reduced percentage of regulatory T-cells and increased CD4+/CD8+ T-cell ratio and this immune imbalance may lead to the initiation of ENL reactions in either permitting productions of antibodies critical to an immune-complex formation or as a cell-mediated immune response in patients with leprosy. Consequently, this study illuminates the role of T-cell activation in the pathogenesis of ENL reaction and challenges the long-standing dogma of immune-complexes as the sole aetiology of ENL reactions

Correlation between Central Memory T Cell Expression and Proinflammatory Cytokine Production with Clinical Presentation of Multibacillary Leprosy Relapse

<div><p>Background</p><p>Despite the efficacy of multidrug therapy, surviving <i>Mycobacterium leprae</i> causes relapse in some leprosy patients, and these patients present signs and symptoms of disease after healing. This study focused on the cellular immune response in relapsed multibacillary patients but also included non-relapsed multibacillary cured individuals, newly diagnosed and untreated multibacillary patients, paucibacillary patients just before the beginning of treatment, and voluntary healthy individuals for comparative analysis.</p><p>Methodology/Principal Findings</p><p>Inhibition of CD86 expression in the blood-derived monocytes and dendritic cells of relapsed multibacillary patients, either <i>ex vivo</i> or after <i>M</i>. <i>leprae</i> antigen stimulation was observed by flow cytometry. In addition, no significant changes in Interferon-gamma (IFN-γ) expression were observed in 5-day culture supernatants of relapsed patients in response to <i>M</i>. <i>leprae</i>, neither before nor after treatment, as measured by ELISA. However, these patients demonstrated a significant increase in central memory CD4+ and CD8+ <i>M</i>. <i>leprae</i>-specific T cells, as assessed by multiparametric flow cytometry. The increase in frequency of central memory T cells in relapsed patients strongly correlated with the bacillary index and the number of skin lesions observed in these subjects. Moreover, cytokine multiplex analysis demonstrated significant antigen-specific production of Interlukin-1beta (IL-1b), IL-6, and Tumour Necrosis Factor (TNF) in the relapsed group with extremely low IL-10 production, which resulted in a high TNF/IL-10 ratio.</p><p>Conclusions/Significance</p><p>Inhibition of CD86 expression may function to reduce effector T cell responses against the <i>M</i>. <i>leprae</i> antigen. Furthermore, the predominance of central memory T cells in association with the high TNF/IL-10 ratio and no observed IFN-γ production may be related to the pathogenesis of relapse in multibacillary leprosy. Therefore, our findings may be a direct result of the clinical presentation, including a number of skin lesions and bacterial load, of relapsed patients. To our knowledge, this is the first study correlating immune response parameters with the clinical presentation of relapsed multibacillary patients.</p></div