ObjectiveTo explore the changes of the B lymphocyte-derived microparticles (BLMPs) in the bronchoalveolar lavage fluid in patients with chronic obstructive pulmonary disease (COPD),and analyze the correlation between BLMPs changes and the stages of the disease. Methods33 COPD patients in acute exacerbation and 12 COPD patients in stable phase in Southwest Hospital,Xinqiao Hospital,and First Affiliated Hospital of Chongqing Medical University between March 2012 and March 2013 were enrolled in the study. 31 subjects who underwent physical examination and bronchoscopy were recruited as control. The lavage fluid specimens were collected through fiberoptic bronchoscopy,then marked with the corresponding antibodies after centrifugation. The numbers of microparticles were analyzed by flow cytometry. ResultsThe number of the BLMPs was significant different among three groups (P<0.05). Compared with the control group and the stable COPD group,the number of BLMPs in the AECOPD group was significantly reduced (P<0.05). Compared with the control group,the number of the BLMPs in the stable COPD group was reduced but with no significant difference (P>0.05). The numbers of BLMPs had no correlation with the smoking history,gender,age and body surface area. ConclusionThe number of BLMPs is reduced in COPD,especially in the acute exacerbation stage,so the reductions of the BLMPs may be associated with the stages of the disease. Smoking,gender,age,body surface area have no effect on the number of BLMPs.