In the present study, in both lung tissue samples and white blood cells from COPD patients, we demonstrated an increase in intracellular signaling that is related to Th17 skewing, which is mediated by transcription factors such as STAT3 and RORγt. Interestingly, in the lung tissue samples, these changes could be observed in patients with mild and moderate disease (COPD I and II) when compared to smokers with no obstruction (NOS group), whereas evaluation of white blood cells revealed that these changes were present only in patients with severe and very severe stages of COPD (COPD III and IV). Here, STAT3 is linked to chronic obstructive pulmonary disease.