CD4 and chronic obstructive pulmonary disease: T cells ratios vary significantly with the progression of the disease showing an intersection point when the number of CD8+T cells reach the same number then CD4+T cells (30%) in patients with 60% of FEV1 predicted, from this point on, there is a steep loss of CD4+T cells compared to CD8+T proliferation; supporting the concept of an extrinsic dysregulation of autoreactives T cells due to loss of Tregs when patients enter in the stages 3 and 4 of GOLD with severe COPD/emphysema [6].