Intravenous Cyclophosphamide Therapy for Anti-IFN-γ Autoantibody-Associated Talaromyces marneffei Infection

High titers of anti-interferon-γ autoantibodies (AIGAs) are an important factor leading to persistent, relapsed, and refractory infections in HIV-negative hosts infected with Talaromyces marneffei (TM). We report 5 patients treated with pulses of high-dose intravenous cyclophosphamide (IVCY) who were followed for 2 years. Before IVCY therapy, all patients had multiple relapses, with a median (interquartile range [IQR]) of 2 (1–3) instances of relapse. The median serum AIGA titers (IQR) were 58 753 (41 203–89 605) ng/mL at diagnosis, 48 189.4 (15 537–83 375) ng/mL before IVCY therapy, and 10 721.2 (5637–13 245) ng/mL at the end of IVCY therapy (P < .05). After 3 months of follow-up, the median AIGA titers (IQR) rose gradually to 21 232.6 (9896–45 626) ng/mL, and to 37 464.2 (19 872–58 321) ng/mL at 24 months (P < .05). Five patients discontinued antimicrobial therapy within 3–12 months after completion of IVCY therapy, but only 1 patient had a relapse. In conclusion, pulses of short-term and high-dose IVCY can effectively reduce AIGA titers.