Serum IgG Subclasses against Dietary Antigens in Children with Type 1 Diabetes

Background: T1D is an autoimmune disorder that has been related to leaky gut, possible due to feeding regimes during the first year of life. IgG reactivity against dietary proteins indirectly assess gut permeability disruption. The aim of this study was to evaluate the association of early feeding regimes with total serum IgG response against related dietary antigens (gliadins, bovine caseins and β-lactoglobulin) in children with T1D at onset and after two years of evolution, and to determine the relative distribution of specific IgG subclasses against these proteins. Methods: A case-control study with 47 T1D children and 15 healthy controls was performed. Their histories of feeding regimes during the first year of life were recorded and a blood sample was collected at the time of the interview. Total IgG indexes and its subclasses (IgG1-4) were determined by ELISA using monoclonal antibodies. Results: An earlier introduction of cow's milk in T1D children was observed as compared to healthy controls. No associations between early diet and the current presence of IgG antibodies were found. However, T1D patients had increased total IgG reactivity to gliadins, caseins and/or β-lactoglobulin. These increases were mainly associated with IgG1, IgG2 and IgG4 subclasses, as observed in other autoimmune diseases with intestinal origin as celiac disease. Gliadins showed the highest potential as antigens in T1D. Conclusions: The IgG reactivity patterns found in T1D children contributes to understand the effects of leaky gut in T1D and the aberrant immune response associated with intolerances and autoimmunity.