STAT3 and chronic obstructive pulmonary disease: Based on this knowledge, we assessed the presence and levels of miRNA-19a and miRNA-221 in BAL macrophage EVs and showed that while smokers without COPD had high levels of both miRNA19 and miRNA221, tuning down EV SOCS3 expression, smokers with COPD had a significantly lower miRNA expression, probably trying, ineffectively, to maintain high levels of SOCS3 to tune down STAT3 expression.