SMOKING ALTERS THE PHENOTYPE OF MACROPHAGES IN INDUCED SPUTUM

To investigate the effect of chronic smoke exposure on pulmonary macro phages (PM), the expression of seven different surface and intracellul ar molecules of PM was studied in induced sputum (IS) samples from hea lthy volunteers-nine smokers and seven non-smokers. Sputum was as indu ced by inhalation of nebulized saline (3.5% NaCl). Cell viability and total cell counts (TCC) were performed immediately. Cell differentials were determined on May-Grunwald Giemsa-stained cytospin preparations. The PM were immunologically characterized by use of the following mon oclonal antibodies: RFD1, RFD7, CD11b, CD54, CD68, CD71 and HLA-DR. Th e stainings were performed with a three-step. indirect immuno-alkaline phosphate method. Viability and TCC did not differ between the groups . Smokers had a higher percentage of macrophages (P<0.05) and a lower proportion of neutrophils (P<0.05). The percentage of macrophages expr essing RFD1, HLA-DR, CD71 (P<0.01 for all) and CD54 (P<0.05) was signi ficantly lower in smokers, whereas the remaining markers were expresse d equally in the two groups. The results indicate that smoking induces a decrease in the expression by PM of surface molecules known to be a ssociated with the antigen-presenting function.