Nontuberculous Mycobacterium-associated immune reconstitution inflammatory syndrome in a non-HIV immunosuppressed patient.

A 69-year-old woman with rheumatoid arthritis, using immunosuppressants, including etanercept-a tumour necrosis factor (TNF)-α antagonist-was referred to our hospital with fever and fatigue. Chest computed tomography revealed cavities in the left upper lobe. As Mycobacterium intracellulare infection was diagnosed, all immunosuppressants were discontinued, and treatment with anti-nontuberculous Mycobacterium drugs was initiated. However, her condition worsened paradoxically. We diagnosed immune reconstitution inflammatory syndrome (IRIS) resulting from the discontinuation of the TNF-α antagonist. Her condition improved with prednisolone treatment. IRIS is generally observed during HIV treatment, but a good understanding of immunosuppressant-related non-HIV IRIS is needed.