Differential Cytokine Gene Expression According to Outcome in a Hamster Model of Leptospirosis

Leptospirosis is a widespread bacterial infection that is transmitted by soil or water contaminated by the urine of infected animals, or directly from these animals. It has highly diverse clinical presentations, making its differential diagnosis difficult. Though most cases are minor and self-resolving, there are also severe forms that include a sepsis pattern and multiple organ failure, and have possible fatal outcomes. Predictors of disease evolution and outcome are scarce, yet they would be very valuable to clinicians as well as to better decipher disease pathogenesis. In this study, we used a hamster model of leptospirosis to evaluate if immune genes were differentially expressed between individuals and if their expression levels could help forecast the outcome of the disease. We found that hamsters that later died from leptospirosis had significantly higher expression levels of both pro- and anti-inflammatory mediators compared to survivors. These results suggest that expression levels of these immune effectors might be helpful predictors of outcome in leptospirosis and that septic shock contributes to fatal leptospirosis

Leptospira interrogans activation of peripheral blood monocyte glycolipoprotein demonstrated in whole blood by the release of IL-6

Glycolipoprotein (GLP) from pathogenic serovars of Leptospira has been implicated in the pathogenesis of leptospirosis by its presence in tissues of experimental animals with leptospirosis, the inhibition of the Na,K-ATPase pump activity, and induced production of cytokines. The aims of the present study were to investigate the induction of IL-6 by GLP in peripheral blood mononuclear cells (PBMC) and to demonstrate monocyte stimulation at the cellular level in whole blood from healthy volunteers. PBMC were stimulated with increasing concentrations (5 to 2500 ng/ml) of GLP extracted from the pathogenic L. interrogans serovar Copenhageni, lipopolysaccharide (positive control) or medium (negative control), and supernatants were collected after 6, 20/24, and 48 h, and kept at -80ºC until use. Whole blood was diluted 1:1 in RPMI medium and cultivated for 6 h, with medium, GLP and lipopolysaccharide as described above. Monensin was added after the first hour of culture. Supernatant cytokine levels from PBMC were measured by ELISA and intracellular IL-6 was detected in monocytes in whole blood cultures by flow-cytometry. Monocytes were identified in whole blood on the basis of forward versus side scatter parameters and positive reactions with CD45 and CD14 antibodies. GLP ( > or = 50 ng/ml)-induced IL-6 levels in supernatants were detected after 6-h incubation, reaching a peak after 20/24 h. The percentage of monocytes staining for IL-6 increased with increasing GLP concentration. Thus, our findings show a GLP-induced cellular activation by demonstrating the ability of GLP to induce IL-6 and the occurrence of monocyte activation in whole blood at the cellular level

Randomized controlled trial of pulse methyl prednisolone × placebo in treatment of pulmonary involvement associated with severe leptospirosis. [ISRCTN74625030]

<p>Abstract</p> <p>Background</p> <p>The lungs are involved in up to 70% of cases of leptospirosis. In the more severe forms-bleeding from the lungs and acute respiratory distress syndrome-the lethality is high. The treatment proposed for leptospirotic pneumonitis includes just care for patients in critical condition. Clinical and experimental studies point to the involvement of immunological mechanisms in the physiopathology of lung damage caused by leptospirosis. The aim of this study is to evaluate pulse treatment with methylprednisolone × placebo for leptospirotic pneumonitis.</p> <p>Study design</p> <p>This is a randomized double-blind clinical trial to test the efficacy of pulse treatment with methylprednisolone in patients with leptospirotic pneumonitis, compared with a placebo. The patients are recruited from three hospitals in the city of Recife, in the Brazilian State of Pernambuco. The exclusion criteria include patients aged under 15 years, a history of hypersensitivity to the use of corticosteroids, the presence of active infection of fungal, tuberculous or bacterial origin apart from the infection by leptospira itself, the presence of hemoconcentration or atypical lymphocyte count on admission to hospital, the presence of co-morbidities that could be responsible for the radiological and gasometric alterations used to diagnose leptospirotic pneumonitis, evidence of recent cranial trauma, neurosurgery, peptic ulcer, and participation in another clinical trial. The patients are followed until they are discharged from hospital or die. The intervention consists of endovenous pulse treatment with 1 g methylprednisolone for three consecutive days in the study group and a placebo in the control group. The primary end-point is mortality from leptospirotic pneumonitis. The secondary end-points are: evolution of lung disease; the occurrence of nosocomial respiratory infection; duration of mechanical ventilation; duration of intensive care unit (ICU) stay; duration of hospital stay; occurrence of other infection-related complications; other respiratory complications; and adverse effects of methylprednisolone. The study is designed to recruit 266 patients and has a statistical "power" of 80% to detect a 50% reduction in mortality.</p> <p>Discussion</p> <p>Lung involvement in leptospirosis is a serious manifestation, with a high and variable mortality rate. There is still no specific clearly-established treatment. Well-designed studies are needed to pave the way towards development of such a treatment.</p

Estudo do lavado broncoalveolar em pacientes com comprometimento pulmonar na leptospirose Study of bronchoalveolar lavage in leptospirosis patients with pulmonary involvement

INTRODUÇÃO: O comprometimento pulmonar é freqüente na leptospirose e caracteriza-se por hemoptise, dispnéia e infiltrados pulmonares bilaterais no radiograma de tórax. Esses achados podem ser compatíveis com hemorragia alveolar, previamente descrita por alguns autores em autópsias e em lavado broncoalveolar. OBJETIVO: Avaliar a presença de hemorragia alveolar, diagnosticada por meio do lavado broncoalveolar, em pacientes portadores de leptospirose com alterações pulmonares, enfatizando-se a importância do método para o diagnóstico precoce da complicação. MÉTODO: Sete pacientes com leptospirose foram submetidos à broncoscopia com lavado broncoalveolar. Todos apresentavam sinais e/ou sintomas respiratórios, e/ou infiltrados no radiograma de tórax, e/ou hipoxemia. A hemorragia alveolar foi definida pelos seguintes achados no lavado: porcentagem de siderófagos e"20%, escore de Golde > 100, e/ou presença de líquido hemorrágico. Foram realizados exame direto e cultura para Leptospiras, com o uso de meios específicos. O diagnóstico da doença foi confirmado por soroaglutinação microscópica para leptospirose. RESULTADOS: O aspecto da broncoscopia foi normal em 5 pacientes, mostrou sangramento na árvore brônquica em 1 caso e sinais inflamatórios em outro. O aspecto do lavado foi hemorrágico em todos os pacientes, configurando o quadro de hemorragia alveolar. A pesquisa direta e a cultura para Leptospiras foram negativas. CONCLUSÃO: A leptospirose deve ser considerada no diagnóstico diferencial das hemorragias alveolares.O lavado broncoalveolar mostrou-se um método eficaz para a detecção de hemorragia alveolar na leptospirose, servindo para orientar a terapêutica imediata, com a finalidade de prevenir sua evolução, caracterizada pela presença de hemoptises maciças e insuficiência respiratória.<br>BACKGROUND: Pulmonary involvement is common in leptospirosis and usually characterized by hemoptysis, dyspnea and diffuse bilateral infiltrates in chest X-rays. Such findings may be compatible with alveolar hemorrhage, already described by some authors both in autopsies and bronchoalveolar lavage (BAL). OBJECTIVE: To evaluate the presence of alveolar hemorrhage, diagnosed through BAL, in bearers of leptospirosis patients with pulmonary involvement emphasizing the methodís importance for early detection of this complication. METHOD: Seven patients with leptospirosis were submitted to BAL. All presented respiratory symptoms and/or infiltrates in the chest X-rays and/or hypoxemia.Alveolar hemorrhage was defined by the following findings in BAL: percentage of siderophages eî20% and/ or Golde score >100 and/or hemorrhagic fluid. Culture and direct tests for leptospirosis were performed in BAL. Diagnosis of disease was confirmed by microscopy serum agglutination. RESULTS: The aspect of the bronchoscopy was normal in five patients, showed blood in the bronchial tree in one case and inflammatory manifestations in another. The BAL aspect was hemorrhagic for all patients portraying alveolar hemorrhage. Culture and direct tests were negative for Leptospiras in the BAL. CONCLUSIONS: Leptospirosis must be taken into account in the differential diagnosis of alveolar hemorrhage. The BAL was confirmed as an efficient method for detection of alveolar hemorrhage in leptospirosis, to recommend immediate therapy for the purpose of preventing its evolution to massive hemoptysis and respiratory failure

Leptospira: the dawn of the molecular genetics era for an emerging zoonotic pathogen.

International audienceLeptospirosis is a zoonotic disease that has emerged as an important cause of morbidity and mortality among impoverished populations. One hundred years after the discovery of the causative spirochaetal agent, little is understood about Leptospira spp. pathogenesis, which in turn has hampered the development of new intervention strategies to address this neglected disease. However, the recent availability of complete genome sequences for Leptospira spp. and the discovery of genetic tools for their transformation have led to important insights into the biology of these pathogens and their pathogenesis. We discuss the life cycle of the bacterium, the recent advances in our understanding and the implications for the future prevention of leptospirosis