Finally, the partial overlap but opposing direction of changes in cytokine profiles generated by (1) PBMCs from fasted vs. fed T2D subjects; and (2) T2D T-cells unable to oxidize glucose (e.g., mimicking a glucose fast from a mitochondrial perspective), e.g., changes in IL-21, -9, -4, -12, are consistent with the interpretation that both glucose and fatty acid-derived metabolites are required for T-cell inflammation in T2D. The gene discussed is IL21; the disease is type 2 diabetes mellitus.