The cytosolic pattern-recognition receptor Nod2 and inflammatory granulomatous disorders

Pattern-recognition receptors are a first tine of defense against invading pathogens. Recent advances in the understanding of innate immunity have revealed a novel family of cytosolic pattern-recognition receptors called Nods, which contain an amino-terminal effector-binding domain, a centrally located nucleotide-binding oligomerization domain (NOD) and a carboxy-terminal ligand recognition domain. Hereditary mutations of Nods have been reported in patients with certain inflammatory diseases; for example, Nod2 mutations are associated with the inflammatory granulomatous disorders, Crohn's disease and Blau syndrome. Missense mutations of Nod2 are also associated with early-onset sarcoidosis, a rare but sporadic disease. Because Nod2 is predominantly expressed in monocytes and recognizes a component of bacteria[ peptidoglycan, analysis of its function may help in understanding the role of the immune system in granuloma formation. (c) 2005 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.