Anti-CD20 (rituximab) therapy for anti–IFN-γ autoantibody–associated nontuberculous mycobacterial infection

Patients with anti-IFN-γ autoantibodies have impaired IFN-γ signaling, leading to severe disseminated infections with intracellular pathogens, especially nontuberculous mycobacteria. Disease may be severe and progressive, despite aggressive treatment. To address the underlying pathogenic IFN-γ autoantibodies we used the therapeutic monoclonal rituximab (anti-CD20) to target patient B cells. All subjects received between 8 and 12 doses of rituximab within the first year to maintain disease remission. Subsequent doses were given for relapsed infection. We report 4 patients with refractory disease treated with rituximab who had clinical and laboratory evidence of therapeutic response as determined by clearance of infection, resolution of inflammation, reduction of anti-IFN-γ autoantibody levels, and improved IFN-γ signaling.