ARG1 and chronic obstructive pulmonary disease: Scrimini et al. observed that the circulating levels of MDSCs (Lin−HLA-DR−CD33+CD11b+) and the serum concentration of Arg-1 were increased, and the surface expression of TCRζ in circulating lymphocytes was reduced to a similar extent among patients with LC, chronic obstructive pulmonary disease (COPD), or both diseases.