CXCL2 and bronchiolitis: Additionally, in mock-primed mice, the degree of neutrophilic infiltration and the increased expression of chemokines and neutrophil activators, especially CXCL1 and CXCL2, into the lungs following PVM inoculation has been positively correlated with the severity of hRSV-induced bronchiolitis [65,66,67,68,69].