Monocyte exposure to LPS induces a transient state in which these cells are refractory to further endotoxin stimulation. This phenomenon, termed endotoxin tolerance (ET), is characterized by a decreased production of cytokines in response to the proinflammatory stimulus. We have established a robust model of ET and have determined the time frame and features of LPS unresponsiveness in cultured human monocytes. A large number of genes transcribed in tolerant monocytes were classified as either "tolerizable" or "nontolerizable" depending on their expression levels during the ET phase. Tolerant monocytes exhibit rapid IL-1R-associated kinase-M (IRAK-M) overexpression, high levels of triggering receptor expressed on myeloid cells-1 (TREM-1) and CD64, and a marked down-regulation of MHC molecules and NF-B2. These cells combine potent phagocytic activity with impaired capability for Ag presentation. We also show that circulating monocytes isolated from cystic fibrosis patients share all the determinants that characterize cells locked in an ET state. These findings identify a new mechanism that contributes to impaired inflammation in cystic fibrosis patients despite a high frequency of infections. Our results indicate that a tolerant phenotype interferes with timing, efficiency, and outcome of the innate immune responses against bacterial infections.
In 2008, the Spanish Society of Pulmonology (SEPAR) published the first guidelines in the world on the diagnosis and treatment of bronchiectasis. Almost 10 years later, considerable scientific advances have been made in both the treatment and the evaluation and diagnosis of this disease, and the original guidelines have been updated to include the latest scientific knowledge on bronchiectasis. These new recommendations have been drafted following a strict methodological process designed to ensure the quality of content, and are linked to a large amount of online information that includes a wealth of references. These guidelines cover aspects ranging from a consensual definition of bronchiectasis to an evaluation of the natural course and prognosis of the disease. The topics of greatest interest and some new areas are addressed, including epidemiology and economic costs of bronchiectasis, pathophysiological aspects, the causes (placing particular emphasis on the relationship with other airway diseases such as chronic obstructive pulmonary disease and asthma), clinical and functional aspects, measurement of quality of life, radiological diagnosis and assessment, diagnostic algorithms, microbiological aspects (including the definition of key concepts, such as bacterial eradication or chronic bronchial infection), and the evaluation of severity and disease prognosis using recently published multidimensional tools.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.