Clinical Trial: Ventilator-Associated Pneumonia (VAP) in Intensive Care Unit (ICU)

Study Status: Terminated
Recruit Status: Unknown status
Study Type: Observational

Official Title: Immune Response in Patients Who Develop Ventilator-Associated Pneumonia (VAP) in Intensive Care Unit (ICU) and the Role of Toll-Like Receptors(TLR2,TLR4,TLR9).

Brief Summary: Ventilator-associated pneumonia (VAP) is very common in the intensive care unit (ICU), affecting 9 to 40% of ICU patients and mortality rates range from 20 to 50% and may reach more than 70% when the infection is caused by multi-resistant and invasive pathogens. The most common pathogens that cause VAP are the Gram(-) bacteria. Findings indicate that TLRs serves as an important signal in the generation of protective innate responses to bacterial pathogens of the lung and that is required for effective innate immune responses against Gram-negative bacterial pathogens. There is genetic evidence that mutations in TLRs increase the risk of developing nosocomial infections. Understanding the TLR system should offer invaluable opportunity for manipulating host immune responses.

Detailed Summary:

INTRODUCTION

Ventilator-associated pneumonia (VAP) typically refers to nosocomial pneumonia developing 48 hours later from endotracheal intubation and mechanical ventilation.ICU patients who receive mechanical ventilation have 4-fold higher risk of developing pneumonia with a rate of 3% per day after day 7 in the intensive care unit. Several risk factors have been reported to be associated with VAP, including the duration of mechanical ventilation, the presence of chronic pulmonary disease, sepsis, acute respiratory distress syndrome (ARDS), neurological disease and trauma. The immune system defends the host against infection. Protective immunity can be divided into innate and adaptive immunity. The innate immune response evolves as a first defence barrier in the host and mounts an immediate, but nonspecific, immune response to rapidly destroy or limit the invaders. The innate defense mechanisms are the external epithelia, the mucosal surfaces, the cells (NK cells, phagocytes) and the complement system.

Adaptive immunity is a second line defence that includes T (cellular) and B (humoral) cell mediated responses. This is specific, targets only pathogens and not self, and has memory to sustain a long-lasting immunity against reinfection. Although the innate immune system lacks the fine specificity of adaptive immunity it can distinguish self from non self. Innate immune recognition is mediated by a system of germline-encoded receptors named pattern recognition receptors (PRRs) that recognize conserved molecular patterns (pathogen-associated molecular patterns, PAMPs) that are associated with microbial pathogens. These receptors are coupled to signal transduction pathways that control expression of a variety of inducible immune-response genes.

TLRs control both innate and adap
Sponsor: University of Thessaly

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Information By: University of Thessaly

Dates:
Date Received: July 8, 2009
Date Started: July 2009
Date Completion: August 2011
Last Updated: July 8, 2009
Last Verified: July 2009