T helper cells play a critical role in the progression of type 1 diabetes, a new study proposes. Led by the University of Eastern Finland, the findings, based on samples from children with genetic risk for type 1 diabetes, could help to explain progression to type 1 diabetes. The investigation suggests that CXCR5−PD-1hi peripheral T helper (Tph) cells are likely key to the development of type 1 diabetes. The research team included scientists from the Universities of Turku, Helsinki and Oulu as well as Harvard University. The researchers demonstrated that the frequency of T helper cells was increased in blood of both children with recently diagnosed type 1 diabetes as well as healthy, autoantibody-positive (at-risk) children.
A cohort of 44 children with newly diagnosed type 1 diabetes, 40 (autoantibody-positive) or at-risk children for type 1 diabetes and 84 autoantibody-negative or healthy control children were analysed. Findings were replicated in a separate cohort of 15 children with newly diagnosed type 1 diabetes and 15 healthy control children.
Researchers found the frequency of circulating T helper cells was increased in children with newly diagnosed type 1 diabetes, and importantly, circulating T helper cells were also increased in autoantibody-positive at-risk children who later progressed to type 1 diabetes.
Type 1 diabetes develops when insulin-producing beta cells in the pancreas are destroyed by the immune system. In addition to genetic susceptibility, the appearance of autoantibodies is predictive of future development of type 1. Autoantibodies are present before clinical onset due to B cell activation against proteins in the pancreatic islets. Activation of B cells was recently attributed to a novel T-cell subset or peripheral T helper cells.
Circulating T helper cells were also increased in autoantibody-positive at-risk children who later progressed to type 1 diabetes.
The results suggest that circulating CXCR5−PD-1hi T helper cells are associated with progression to clinical type 1 diabetes. T helper cells have the potential to serve as biomarkers of disease progression and as a target for immunotherapy in type 1 diabetes.