Mycobacterium intracellulare Infection in a Japanese Patient with Signal Transducer and Activator of Transcription-3 Gain-of-function Syndrome

Signal transducer and activator of transcription-3 (STAT3) gain-of-function (GOF) syndrome predisposes patients to autoimmunity diseases. Yet, nontuberculous mycobacterial (NTM) infections have rarely been described. We herein report a teenage Japanese patient with genetically confirmed STAT3-GOF syndrome who developed Mycobacterium intracellulare disease. Combination antimycobacterial chemotherapy reduced the bacterial burden; however, the refractory NTM infection relapsed after initiation of adjunctive tofacitinib therapy. The present case demonstrates that host-directed therapy must be combined with prolonged antimycobacterial regimens to control drug-resistant NTM in patients with inborn errors of immunity.