LEPR and type 2 diabetes mellitus: It was demonstrated that the intensity of the serological response to SARS-CoV-2 is positively correlated with the severity of the clinical symptoms (Legros et al., 2021; Korobova et al., 2022; Wang et al., 2022; Yan et al., 2022), which explains why higher and prolonged SARS-CoV-2 N-specific IgG (IgG1, IgG2b, and IgG2c) levels were observed in the serum of the Lepr-deficient, T2DM mice when compared to the lean mice.