 ACD is an immune driven disorder, developing in subjects suffering from chronic inflammatory diseases. COPD is a disorder very likely to be associated to ACD due to its systemic inflammatory dimension. Currently, data on the prevalence of ACD and on the level of inflammatory markers which are implicated in the pathogenesis of ACD in COPD subjects are limited and controversial. Furthermore, there is no data on the effect of ACD on exercise capacity of COPD subjects. 