Multiple refractory intracellular pathogen infections in a human immunodeficiency virus-negative patient with anti-interferon-γ autoantibodies: a case report

BACKGROUND: The clinical presentation of adult-onset immunodeficiency with anti-interferon (IFN)-γ autoantibodies with intracellular pathogens can be highly variable, which can lead to misdiagnosis during the early stage of disease. CASE PRESENTATION: We report a complex case of a 54-year-old Chinese male who was human immunodeficiency virus-negative. He had a presence of anti-IFN-γ autoantibodies and suffered from various intracellular pathogenic infections. The patient was admitted to our hospital for the first time in July 2016 with severe pneumonia, and he experienced multiple pneumonia infections between 2017 and 2019. In March 2019, the patient was hospitalized due to pulmonary lesions and multiple-bone destruction. During hospitalization, the patient was confirmed to have disseminated Talaromyces marneffei infection and was successfully treated with antifungal therapy for 1 year. In June 2021, Mycobacterium kansasii infection was detected by positive culture and progressive bone destruction. A high concentration of anti-IFN-γ antibodies was observed in the patient’s serum. In addition, Listeria monocytogenes was isolated by blood culture, and the presence of L. monocytogenes in cerebrospinal fluid was confirmed by next-generation sequencing. Following anti-non-tuberculous mycobacteria (NTM) therapy and anti-bacterial therapy, the patient’s symptoms, pulmonary lesions, and bone destruction gradually improved. CONCLUSIONS: Although the clinical presentation of adult-onset immunodeficiency with anti-IFN-γ autoantibodies can be highly variable, the diagnosis should be considered if patients suffer from unexplained repeated bacterial or opportunistic infections. Conventional and advanced molecular testing should be used, as needed, for microbiological diagnoses among this special immunodeficient population.