For example, in a vascular disease model of vaso-occlusion in sickle cell disease, it has been shown that stress promotes vaso-occlusion by eliciting a glucocorticoid hormonal response that augments gut permeability, leading to microbiota-dependent IL-17A secretion from T helper 17 cells of the lamina propria, followed by the expansion of the circulating pool of aged neutrophils that trigger vaso-occlusions (Xu et al., 2020). This evidence concerns the gene IL17A and sickle cell disease.