2017 Volume 29 Issue 4 Pages 292-299
Nontuberculous mycobacterium collectively refers to a large number of species of mycobacteria other than Mycobacterium tuberculosis. Nearly 90% of nontuberculous mycobacteria (NTM) diseases are infections by Mycobacteria avium complex (MAC). Among NTM diseases (NTMD), Mycobacterium abscessus infection is resistant to various therapies. The main infectious site of NTMD is the lungs. There are two major types of pulmonary lesion caused by NTMD: one is milder form nodular-bronchiectatic type, and the other is severe form fibro-cavity type. For the diagnosis of NTMD, chest CT findings compatible with NTMD and detection of mycobacteria with sputum twice or more are nessesary. There are two times as many NTMD infections in RA patients than in the general population, and ten times as many NTMD infections in RA patients receiving TNF-alpha blocker than in the general population. In RA patients with NTMD, b-DMARDs are contraindicated, so we cannnot prescribe those agents to such patients. In 2014, the Japanese Respiratiry Society created a guideline for b-DMARDs therapy for RA patients with NTMD. This guideline allows use of b-DMARDs therapy for such patients only in the case of MAC infection and the milder nodular-bronchiectatic type. Therefore, although b-DMARDs can be can introduced in to anti-RA therapy for RA patients with NTMD, b-DMARD therapy should be applied to RA patients with NTMD very carefully.
