SLPI and type 2 diabetes mellitus: With regard to the relationship between the two genes and the immune environment of T2DM, ARHGEF9 expression was negatively correlated with the proportions of resting NK T cells, endothelial cells, aDCs, and mesangial cells, whereas SLPI expression was positively correlated with the proportions of epithelial cells, M1 macrophages, mast cells, and basophils (Figure 9E).