[Immunological background on non-tuberculous mycobacteriosis].

Nontuberculous mycobacteria (NTM) pulmonary disease is increasing and Mycobacterium avium complex (MAC) is the most common cause. NTM pulmonary disease has been linked in a distinct patient phenotype such as thin, post-menopausal women. Their predisposition to infection with NTM suggests that immunologic responses to NTM potentially contribute to pathogenesis of NTM lung disease. In this symposium, we asked four speakers to talk mainly about the immunologic pathogenesis. The topics included immunosuppressive macrophages in patients infected with MAC, pathological findings of MAC pulmonary disease, poor nutrition conditions associated with the progressive NTM pulmonary disease, and hypersensitivity reaction referred to as "hot tub lung". We hope that the discussion through this symposium will lead to clinical usefulness of this disease.