Patients with comorbid COVID-19 and T2D exhibited significantly reduced expression of cytotoxic mediators (GZMB, perforin and IFN-γ) alongside elevated IL-6 levels compared with other groups, demonstrating a synergistic impairment of NK cell effector function in the dual-pathology cohort (Figure 7). This evidence concerns the gene PRF1 and type 2 diabetes mellitus.