Clinical characteristics of acquired anti-IFN-γ autoantibodies in patients infected with non-tuberculous mycobacteria: a prospective cohort study.

Background: Patients with positive anti-IFN-γ autoantibodies (AIGAs) are characterized by susceptibility to disseminated infection by multiple pathogens. The clinical characteristics of non-tuberculous mycobacterial (NTM) infection with AIGAs positivity remain unclear.

Methods: A prospective cohort study was conducted at the First Affiliated Hospital of Guangxi Medical University from January 2021 to January 2024. A total of 93 patients diagnosed with NTM infection were divided into two groups: AIGAs-positive with NTM infection and AIGAs-negative with NTM infection. The clinical manifestations, laboratory data, imaging examination, and pathogens were analyzed to characterize the disease.

Results: A total of 44 AIGAs-positive and 49 AIGAs-negative patients with NTM infection were enrolled. Disseminated infections were significantly more common among AIGAs-positive patients (P < 0.001), with frequent co-infections involving Talaromyces marneffei (TM) and viruses. Additionally, AIGAs-positive patients exhibited elevated inflammatory markers and immunoglobulins. In the AIGAs-positive group, lymph nodes, bones, skin, and blood were the most frequently affected sites. Chest CT scans exhibited a range of findings. Over a mean follow-up period of 36 months, 56.82% of patients with AIGAs positivity experienced exacerbations despite undergoing regular anti-NTM therapy.

Conclusions: AIGAs-positive patients with NTM infection exhibit elevated inflammatory markers, abnormal immune indicators, and coagulation function. Disseminated infections involving multiple organs are common, with frequent co-infection with TM and viruses. These patients may have unique symptoms, signs, and imaging findings compared to AIGAs-negative patients. Recurrence is common among these patients, highlighting the need for timely identification and intervention.