IL17A and pulmonary emphysema: In our study, one explanation for the mitigation of the emphysema was decreased levels of pro-inflammatory factors in the lungs (IL-1β and CXCL1/KC) and circulation (TNF-α, IL-1β, and IL-17A) by hUC-MSCs which may associate with the reduction of the neutrophil infiltration in emphysematous mice.