INFLAMMATORY AND T-CELL PROFILE OF ASTHMATIC AIRWAYS 6 HOURS AFTER LOCAL ALLERGEN PROVOCATION

T cells in the airways are considered to play a key role in orchestrat ing the inflammatory response of asthma through the elaboration of spe cific cytokines. Using flow cytometry we have investigated the T-cell response of sensitized asthmatic airways 6 h after local allergen prov ocation. Twelve subjects with atopic asthma underwent bronchoalveolar lavage (BAL) before and 6 h after local instillation of allergen into the right middle robe (RML) and saline into the right upper lobe (RUL) . Allergen challenge produced a significant 26% fall in FEV(1), an inc rease in eosinophils in BAL at 6 h, and at 24 h an increase in methach oline responsiveness compatible with late-phase airway inflammation. W hen compared with saline challenge, allergen produced an overall decre ase in the number of BAL lymphocytes from 21.3 +/- 2.8% to 16.0 +/- 3. 08% of total cells but no change in the proportion of CD4(+), CD8(+), CD25(+), or HLA-DR(+) cells. Allergen provocation reduced the proporti on of T cells expressing the beta(2) integrin lymphocyte functional an tigen-1 (LFA-1) from 72.5 +/- 30 to 43.9 +/- 9.1 mean fluorescent unit s (p < 0.01) and a similar trend in intercellular adhesion molecule-1 (ICAM-1) (p = 0.08). These results indicate that late-phase inflammato ry events 6 h after local allergen provocation involve the selective r etention of airway T cells expressing specific cell adhesion molecules .