Dysregulated STAT1 gain-of-function:Pathogen-free autoimmunity and fungal infection

Inborn errors of the signal transducer and activator of transcription 1(STAT1)result in four types of immunodeficiency disease with varying degrees of impaired STAT1 function:autosomal recessive(AR)complete STAT1 deficiency,AR partial STAT1 deficiency,autosomal dominant(AD)STAT1 deficiency,and AD STAT1 gain-of-function(STAT1-GOF).Of which,the STAT1-GOF mutations promote a clinical syndrome of immune dysregulation characterized by recurrent infections,especially chronic mucocutaneous candidiasis(CMC)and Talaromyces marneffei infection and predisposition to humoral autoimmunity.STAT1-GOF mutations lead to enhanced phosphorylation of STAT1(pSTAT1),delayed dephosphorylation,and impaired nuclear dephosphorylation.As a result,the development of T helper(Th)17 cells is impaired,limiting the production of interleukin(IL)-17,which plays an important role in antifungal immunity.Additionally,mutations can also cause a decrease in the proportion of CD4^(+),CD8^(+),and natural killer(NK)cells.Recent research demonstrated that in the absence of overt infection,STAT-GOF mice can disrupt naïve CD4^(+)T cell homeostasis and promote expansion and differentiation of abnormal T-follicular helper/T-helper 1-like(Tfh/Th1-like)T cells and germinal center-like(GC-like)B cells,and thus reminds us of the complex molecular mechanism of autoimmune disease with/without fungal infection,which may further involve specific clinical treatment including antifungal and anti-autoimmunity therapies.In addition,sex and location of mutation were also associated with the clinical phenotype.Individuals with DNA binding domain(DBD)mutations had a higher prevalence of autoimmunity and aberrant B cell activation.Disrupted CD4^(+)T cell homeostasis occurred sooner and more robustly in females,highlighting the importance of specific treatment to normalize STAT1 expression and restore immune tolerance in patients with STAT1-GOF syndrome.Herein,we provide a comprehensive review of STAT1-GOF aiming to further clarify the regulatory mechanism of cellular and humoral immune deficiency in patients with fungal infection with or without autoimmunity.

Genetic susceptibility to Candida infection： a new look at an old entity

The identification of the first molecular defect leading to Mendelian Susceptibility to Mycobacterial Disease ;MD）,1 a rare syndrome conferring predisposition to（MSMD）,1 a rare syndrome conferring predisposition to disease caused by weakly virulent mycobacteria （such as Mycobacterium bovis, Bacille Calmette Gu6rin vaccines and environmental mycobacteria）, has led to a paradigm shift in the field of primary immunodeficiencies in the last two decades. The ＂classic＂ patient with multiple immunologic abnormalities, conferring a broad susceptibility to multiple and recurrent infectious diseases caused by both weakly pathogenic and more virulent microorganisms, was the main Primary Immunodeficiency （PID） phenotype identified. Since 1996, mutations causing MSMD have been found in at least 6 genes related to interferon （IFN）-7-mediated immunity.2