Additionally, COPD impaired the suppressive capacity of CD4<sup>+</sup>Foxp3<sup>+</sup> regulatory T cells through downregulation of key immunosuppressive genes, including those associated with FoxP3<sup>+</sup>, TIGIT<sup>+</sup>, and LPS-responsive Tregs. This evidence concerns the gene CD4 and chronic obstructive pulmonary disease.