CD4 and chronic obstructive pulmonary disease: Whereas activated DCs secondary to cigarette smoke exposure have been reported to skew adaptive immune response towards Th1 and cytotoxic T cell lymphocyte (CTL) responses (known hallmarks of chronic inflammation in COPD) (442), currently, it’s not known how dysbiosis induces DCs into either type 1 or 2 DCs, which ultimately dictates CD4+T cell phenotypes.