CD4 and pulmonary emphysema: In the model of elastase-induced emphysema used herein, two doses of MSCs, compared to a single dose, yielded further decrease levels of TNF-α in lung tissue, fractional area of hyperinflation in the lung, Lm, neutrophil cell counts in lung tissue, BALF neutrophil and lymphocyte cell counts, thymus total and CD8+ cell counts, and cLN CD4+ and CD8+ T cell counts, while increasing elastic fiber content in the lung parenchyma and reducing the diastolic right ventricle area.