LAUSR

Background High-titer anti-interferon (IFN)-γ autoantibodies are strongly associated with intracellular pathogens such as nontuberculous mycobacteria and Talaromyces marneffei , but they are not as commonly associated with Talaromyces marneffei co-infected with Mycobacterium tuberculosis . Case presentation Herein, we report a case of an HIV-negative Chinese man with a severe, disseminated co-infection of Talaromyces marneffei and Mycobacterium tuberculosis , who had a high-titer of anti IFN-γ autoantibodies and a CFI heterozygous nonsense gene mutation. The patient rapidly developed sepsis and died. Through by flow cytometry for CD4 + T cells’ intracellular phosphorylated STAT-1 and Th1 cells (CD4 + IFN-γ + cells), we found that the patient’s serum can inhibited IFN γ-induced CD4 +  T cells’ STAT-1 phosphorylation and Th1 cell differentiation in normal peripheral blood mononuclear cells, but this phenomenon was not observed in normal control’s serum. In addition, the higher serum concentration in the culture medium, the more obvious inhibition of Th1 cell differentiation. Conclusions For HIV-negative individuals with relapsing, refractory, fatal double or multiple intracellular pathogen infections, especially Talaromyces marneffei , clinicians should be aware that if they might be dealing with adult-onset immunodeficiency syndrome due to high-titer anti-IFN-γ autoantibodies. Systematic genetic and immunological investigations should also be performed.