Diminished IFN-γ response to diabetes-associated autoantigens in children at diagnosis and during follow up of type 1 diabetes

• BackgroundImbalance of T-helper (Th)1- and Th2-like cytokines has been associated with type 1 diabetes. We therefore studied the immune deviation in antigen-specific T cells from diagnosis onwards in type 1 diabetic children.MethodsPeripheral blood mononuclear cells (PBMC) were collected from 15 children after 4 days, 3 months and 18 months of being diagnosed with type 1 diabetes, from 15 healthy children matched by age and gender to the type 1 diabetic children and from 14 children with and 35 children without HLA-risk genes. Secretion of interferon-γ (IFN-γ) and interleukin-4 (IL-4) was detected by ELISPOT after stimulation with glutamic acid decarboxylase (GAD65, protein and aa 247–279), recombinant tyrosinphosphatase (IA-2), insulin, ovalbumin and phytohaemagglutinin (PHA).ResultsSecretion of IFN-γ in PBMC stimulated with GAD65 (p < 0.05), the GAD65-peptide (p < 0.01), IA-2 (p < 0.01), and insulin (p < 0.01) was lower in diabetic children at diagnosis than in healthy children. Stimulation of PBMC with GAD65 and IA-2 decreased the secretion of IFN-γ in children with HLA-risk genotype. Spontaneous and antigen-induced IFN-γ secretion increased significantly after diagnosis of the disease, but did not exceed the levels observed in healthy children. Fasting C-peptide levels at diagnosis correlated with insulin-induced IFN-γ (R = 0.52; p = 0.05) and negatively with spontaneous IL-4 secretion (R = −0.62; p < 0.05).ConclusionA diminished IFN-γ secretion and the association of fasting C-peptide levels with cytokine response in children with type 1 diabetes suggest that factors related to β-cell function in type 1 diabetes may modify T-cell function. Thus, the T-cell responses detected at or after diagnosis may not reflect the pathogenic process leading to type 1 diabetes.

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