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. The gene discussed is ARG1; the disease is laryngotracheoesophageal cleft.