Neutrophils. Neutrophil lung infiltration and the expression levels of chemoattractants, CXCL1 and CXCL8, are increased in patients unresponsive to corticosteroids, implicating neutrophils in corticosteroid insensitivity in asthma and COPD [127,128,129,130,131]. Here, CXCL8 is linked to chronic obstructive pulmonary disease.