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

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