title: The role of pattern recognition receptors in lung sarcoidosis.
abstract: Sarcoidosis is a granulomatous disorder of unknown etiology. Infection, genetic factors, autoimmunity and an aberrant innate immune system have been explored as potential causes of sarcoidosis. The etiology of sarcoidosis remains unknown, and it is thought that it might be caused by an infectious agent in a genetically predisposed, susceptible host. Inflammation results from recognition of evolutionarily conserved structures of pathogens (Pathogen-associated molecular patterns, PAMPs) and/or from reaction to tissue damage associated patterns (DAMPs) through recognition by a limited number of germ line-encoded pattern recognition receptors (PRRs). Due to the similar clinical and histopathological picture of sarcoidosis and tuberculosis, Mycobacterium tuberculosis antigens such early secreted antigen (ESAT-6), heat shock proteins (Mtb-HSP), catalase-peroxidase (katG) enzyme and superoxide dismutase A peptide (sodA) have been often considered as factors in the etiopathogenesis of sarcoidosis. Potential non-TB-associated PAMPs include lipopolysaccharide (LPS) from the outer membrane of Gram-negative bacteria, peptidoglycan, lipoteichoic acid, bacterial DNA, viral DNA/RNA, chitin, flagellin, leucine-rich repeats (LRR), mannans in the yeast cell wall, and microbial HSPs. Furthermore, exogenous non-organic antigens such as metals, silica, pigments with/without aluminum in tattoos, pesticides, and pollen have been evoked as potential causes of sarcoidosis. Exposure of the airways to diverse infectious and non-infectious agents may be important in the pathogenesis of sarcoidosis. The current review provides and update on the role of PPRs and DAMPs in the pathogenesis of sarcoidsis.
authors.affiliation: Department of Immunology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Esmaeil
authors.initials: E
authors.lastname: Mortaz
authors.affiliation: Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Adcock
authors.affiliation: Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Atefhe
authors.initials: A
authors.lastname: Abedini
authors.affiliation: Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Electronic address: Ardakiani@yahoo.com.
authors.forename: Arda
authors.initials: A
authors.lastname: Kiani
authors.affiliation: Mycobacteriology Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Kazempour-Dizaji
authors.affiliation: Department of Pathology and Laboratory Medicine, University of California, Los Angeles (UCLA), USA.
authors.forename: Masoud
authors.initials: M
authors.lastname: Movassaghi
authors.affiliation: Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Sciences, Utrecht University, Utrecht, The Netherlands; Nutricia Research Centre for Specialized Nutrition, Utrecht, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Garssen
mesh_terms: D000818:Animals; D006801:Humans; D008171:Lung Diseases / Q000378:metabolism*; D051192:Receptors, Pattern Recognition / Q000378:metabolism*; D012507:Sarcoidosis / Q000378:metabolism*
chemical_list: D051192:Receptors, Pattern Recognition
keywords: Mycobacteria; Pattern recognition receptors; Propionibacterium; Sarcoidosis; TLR2; TLR4