Interferon and interferon-inducible gene activation in patients with type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease that is thought to be triggered by environmental factors in genetically susceptible individuals. Enteroviruses have been mentioned as the most probable induction component of the disease. Nevertheless, the literature is controversial regarding the association of T1D with viral infection and first-line antiviral defence components, for example type I interferons (IFNs). Our aim was to test the hypothesis that an abnormality in IFN-stimulated gene patterns may cause a failure in immunological tolerance and, thereby, initiate T1D as an autoimmune disorder. We studied material from 64 T1D and 36 control subjects, divided into two age groups: <10 years and ≥10 years old. Using a relative gene expression method, we observed a lower expression of interferon-induced helicase 1 (IFIH1) and other type I IFN-induced genes in the blood cells of T1D subjects, especially subjects under 10 years old, in spite of their higher IFN levels as measured by the pSTAT1-inducing capacity of their sera. Likewise, freshly purified CpG-stimulated cells from T1D patients showed significantly lower upregulation of IFN-induced genes, that is IFIH1 and CXCL10, compared to cells from the control group. The identified dysregulation in the IFN-α-induced antiviral response in T1D patients, especially in early childhood, could be one of the factors affecting T1D development.