Peer-review started: October 24, 2014
First decision: January 8, 2015
Revised: January 24, 2015
Accepted: February 9, 2015
Article in press: February 10, 2015
Published online: March 28, 2015
Processing time: 175 Days and 16.1 Hours
Sarcoidosis is a systemic granulomatous disease of undetermined etiology, and it primarily affects the lungs and lymphatic system but may involve other organs. Recently, there have been several new insights in Japanese patients. The frequency of cardiac, ocular, and cutaneous sarcoidosis has increased in Japan, whereas, the proportion of patients with bilateral hilar lymphadenopathy decreased from 1960 to 2004. Propionibacterium acnes (P. acnes) has been studied extensively as one of the causative microorganism for granuloma formation, particularly in Japan. P. acnes-specific monoclonal antibodies are useful for diagnosing sarcoidosis. The potential association between smoking and sarcoidosis has been evaluated in a Japanese study, which found a higher prevalence of sarcoidosis among young smokers than that in previous reports. Recently, 18F-fluorodeoxyglucose positron-emission tomography, which permits visualization of activated inflammation, and endobronchial ultrasonography-guided transbronchial needle aspiration have been increasingly used to diagnose sarcoidosis. Cardiac sarcoidosis is found to be the main cause of death in Japan. The 2006 revised Japanese guidelines for diagnosing cardiac sarcoidosis are useful, particularly for subclinical cardiac sarcoidosis patients. Further studies and international communication and evaluation are needed to determine the causes of sarcoidosis, identify the risk factors for progressive disease, and develop new and effective treatments.
Core tip: Sarcoidosis, a systemic granulomatous disease of undetermined etiology, is characterized by a variable clinical presentation and course. Propionibacterium acnes (P. acnes)-specific monoclonal antibodies can detect P. acnes, a causative microorganism, and are useful for diagnosing sarcoidosis. The importance of 18F-fluorodeoxyglucose positron-emission tomography and endobronchial ultrasonography-guided transbronchial needle aspiration to diagnose sarcoidosis is progressively increasing. Cardiac sarcoidosis is the main cause of death in Japan. The 2006 Japanese guidelines for diagnosing cardiac sarcoidosis are useful, particularly for subclinical cardiac sarcoidosis patients. Further studies and international communication and evaluation are needed to improve our management of sarcoidosis.