Le sepsis est à l’origine d’une dysfonction immunitaire prolongée responsable d’infections nosocomiales et d’une mortalité tardive élevée. Sa physiologie complexe demeure mal connue et il n’existe aucun traitement spécifique en dehors de l’antibiothérapie et des thérapeutiques de suppléance d’organes. Nous nous sommes intéressés au rôle des cellules myéloïdes dans cette dysfonction immunitaire. Nous avons pu montrer qu’il existe chez les patients atteints de sepsis une augmentation du nombre de cellules suppressives d’origine myéloïde monocytaires (M-MDSC) CD14+HLA-DRlow/- et granulocytaires (G-MDSC) identifiées comme des granulocytes de faible densité CD14-CD15+. Ces cellules sont responsables d’une activité Indoléamine 2,3-dioxygénase (IDO) et arginase 1, et leur déplétion permet de restaurer la prolifération des lymphocytes T in vitro. L’augmentation précoce des G-MDSC prédit la survenue ultérieure d’infections nosocomiales. De même, l’augmentation de l’activité IDO et de l’arginase 1 plasmatique sont associées à un mauvais pronostic. Au total, nous avons pu démontrer que les cellules myéloïdes acquièrent un phénotype suppresseur en partie responsable de l’immunodépression acquise et du pronostic péjoratif chez les patients septiques. Afin de restaurer les capacités immunitaires des patients, les MDSC pourraient devenir une future cible thérapeutique. / Sepsis results in a sustained immune dysfunction responsible for poor prognosis and nosocomial infections. Sepsis physiology remains poorly understood and no treatment exists currently, excepted from antibiotherapy and life-support techniques. We asked if myeloid cells could play a role in this sustained immune dysfunction. We demonstrated that Peripheral CD14+HLA-DRlow/- monocytic-myeloid-derived suppressor cells (MDSCs) and CD14-CD15+ low-density granulocytes identified as granulocytic- (G-)MDSCs were increased in septic patients. In vitro, arginase and IDO activities relied on MDSCs and depletion of both subsets restored T-cell proliferation. The initial proportion of G-MDSC predicted occurrence of nosocomial infections. Similarly, high plasma Indoleamine 2,3-dioxygenase (IDO) activity and arginase 1 level were associated with poor outcome. Altogether, our results demonstrate that myeloid cells acquire suppressive functions during sepsis, partially responsible for the sustained immune dysfunction and poor outcome. MDSCs may become a future therapeutic target to restore the immune capacities of septic patients.

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Indiana University-Purdue University Indianapolis (IUPUI)

Introduction: Despite being one of the most preventable diseases, TB still remains a serious and largely neglected disease. Nurses as compared to the general population are at greater risk of acquiring nosocomial TB. This study was conducted to describe the perceptions of nurses on the underlying contributory factors that may lead to the spread of TB in the clinics treating TB patients. Methods: Quantitative, non – experimental, descriptive, exploratory and cross sectional design was used. A structured and pretested questionnaire was used. Findings: The key contributory factors identified were insufficient TB training for staff and lack of knowledge on the TB legislative framework and TB policy directives. Conclusion: The findings indicate the need for a comprehensive TB infection prevention and control policy, with associated standards for provision and practice. / Health Studies / M.A. (Public Health)

Introduction: Despite being one of the most preventable diseases, TB still remains a serious and largely neglected disease. Nurses as compared to the general population are at greater risk of acquiring nosocomial TB. This study was conducted to describe the perceptions of nurses on the underlying contributory factors that may lead to the spread of TB in the clinics treating TB patients. Methods: Quantitative, non – experimental, descriptive, exploratory and cross sectional design was used. A structured and pretested questionnaire was used. Findings: The key contributory factors identified were insufficient TB training for staff and lack of knowledge on the TB legislative framework and TB policy directives. Conclusion: The findings indicate the need for a comprehensive TB infection prevention and control policy, with associated standards for provision and practice. / Health Studies / M.A. (Public Health)