Hyperglycemia-triggered lipid peroxidation destabilizes STAT4 and impairs anti-viral Th1 responses in type 2 diabetes.

Patients with type 2 diabetes (T2D) are more susceptible to severe respiratory viral infections, but the underlying mechanisms remain elusive. Here, we show that patients with T2D and coronavirus disease 2019 (COVID-19) infections, and influenza-infected T2D mice, exhibit defective T helper 1 (Th1) responses, which are an essential component of anti-viral immunity. This defect stems from intrinsic metabolic perturbations in CD4 T cells driven by hyperglycemia.