Anti-interferon-gamma Antibody-seropositive Disseminated Nontuberculous Mycobacterial Infection Mimicking POEMS and TAFRO Syndromes

Disseminated nontuberculous mycobacterial infection (DNTM) is typically observed in immunocom-promised hosts. Recently, it has been reported that healthy individuals with serum neutralizing autoantibodies for interferon (IFN)-gamma can also develop DNTM. We herein report a case of anti-IFN-gamma antibody-seropositive DNTM caused by Mycobacterium kansasii with symptoms mimicking TAFRO or POEMS syndrome, includ-ing anasarca, organomegaly, skin pigmentation, polyneuropathy, osteosclerotic change, thrombocytopenia, se-rum M protein, high C-reactive protein level, and reticulin fibrosis. The combination of antimicrobial chemo-therapy with glucocorticoid and intravenous immunoglobulin improved his symptoms. Glucocorticoids may be an effective method of suppressing the production of anti-IFN-gamma antibodies in DNTM.