IDH3A and Hyperglycemia: Interestingly, the decreasing percentage of TIGIT+ Tregs under hyperglycemia in culture was also associated with changes suggesting limited glucose uptake and metabolism in Tregs, such as the decreasing percentage of GLUT3+ Tregs (which allows glucose transport into the cell) and the decreasing activity of hexokinase (which starts glycolysis), isocitrate dehydrogenase (which utilizes pyruvate in the Krebs cycle), and CCR5 (a chemokine that takes part in T cell recruitment and migration).