CXCR2 and hypertensive disorder: To determine whether CXCL1 and CXCR2 are associated with HR in humans, we examined serum CXCL1 levels and the number of CXCR2+ immune cells as well as other related risk factors in healthy controls (n = 40) and patients with HR (n = 40) and hypertension (HP, n = 40).