CCL2 and diabetes mellitus: As shown in Figure 1, treatment with quercetin largely inhibited SARS-CoV-2 N protein-induced F4/80+ macrophages infiltrating the diabetic kidney (Figure 1A) and greatly suppressed the mRNA expression of IL-6, TNF-α, and MCP-1 while increasing the expression of IL-4 and IL-10 mRNA levels (Figure 1B, C).