CD14 EXPRESSION AND SOLUBLE CD14 AFTER SEGMENTAL ALLERGEN PROVOCATIONIN ATOPIC ASTHMA

Allergic asthma is associated with the recruitment of activated inflam matory cells after allergen challenge, Surface expression of CD14 has been proposed as a marker of cell activation and differentiation. We t herefore measured CD14 expression on activated macrophages and granulo cytes as well as soluble CD14 (sCD14) concentrations in peripheral blo od and bronchoalveolar lavage (BAL) following segmental allergen provo cation (SAP) with individually standardized doses of allergen in eight patients with allergic asthma, Two segments of the right lung were ch allenged with allergen, Two segments of the left lung, into which sali ne was instilled, served as controls, CD14 expression on macrophages a nd granulocytes was determined by flow-cytometry and concentrations of interleukins and sCD14 were analysed by enzyme-linked immunosorbent a ssay (ELISA) 10 min and 18 h after challenge. Soluble CD14 concentrati ons remained unchanged in BAL fluid after saline challenge and 10 min after SAP, but increased significantly 18 h after SAP. Although macrop hage numbers increased 18 h after SAP, CD14 expression on these cells did not change, Unlike macrophages, granulocyte numbers correlated wit h sCD14 levels 18 h after SAP while their CD14 expression decreased si gnificantly, Furthermore, sCD14 correlated with interleukin (IL)-13 co ncentrations 18 h after SAP. An increase in soluble CD14 can be observ ed 18 h but not 10 min after segmental allergen provocation suggesting local release of this surface antigen. Our findings imply that CD14-m ediated cell activation following segmental allergen provocation could play a role in asthmatic inflammation.