INCREASED BRONCHOALVEOLAR GRANULOCYTES AND GRANULOCYTE MACROPHAGE COLONY-STIMULATING FACTOR DURING EXACERBATIONS OF CHRONIC-BRONCHITIS/

Although inflammatory changes are found throughout the airways of pati ents with chronic bronchitis, the mechanisms of the pathogenesis of ch ronic bronchitis are still unclear, The aim of this study was to inves tigate airways inflammation in patients with and without an exacerbati on of bronchitis. Thirteen chronic bronchitic patients and nine normal subjects were studied, Eight of the patients were studied under basel ine conditions (B), and five during an exacerbation of bronchitis (E). Bronchoscopy and bronchoalveolar lavage (BAL) with cytological analys is were performed, and the levels of granulocyte/macrophage colony-sti mulating factor (GM-CSF) were determined in sera and in BAL supernatan ts by a solid phase enzyme immunoassay. Compared with patients under b aseline conditions, chronic bronchitic patients with an exacerbation h ad increased numbers of BAL neutrophils (10+/-3 and 83+/-18x 10(3) cel ls.mL(-1), respectively; p<0.0001) and of BAL eosinophils (1.9+/-0.5 a nd 6.7+/-1.9x10(3) cells.mL(-1), respectively; p=0.014). Patients with chronic bronchitis, as a whole, had significantly increased levels of BAL GM-CSF compared to control subjects (36+/-5 and 19+/-4 pg.mL(-1), respectively; p=0.035), and similar levels of serum GM-CSF. Serum lev els of GM-CSF were markedly increased in chronic bronchitic patients w ith an exacerbation, as compared with patients under baseline conditio ns (1.4+/-0.4 and 13+/-1 pg.mL(-1), respectively; p <0.0001). BAL leve ls of GM-CSF were also increased in chronic bronchitic patients with a n exacerbation (25+/-5 and 53+/-8 pg.mL(-1), respectively; p=0.009). D uring exacerbations of chronic bronchitis there are changes in the cel l populations in bronchoalveolar lavage of patients consistent with a recruitment of polymorphonuclear leucocytes in the airway lumen. The i ncreased levels of granulocyte/macrophage colony-stimulating factor mi ght suggest a role for this cytokine in the inflammatory processes of chronic bronchitis.