Nasal mucosal response to repeated challenges with pollen allergen.

In order to explore the dynamics of the cellular response of the airway mucosa to allergen exposure, controlled daily allergen challenges were performed for 7 days during the pollen-free winter months in nine patients with strictly seasonal allergic rhinitis caused by birch pollen allergen. Symptoms obtained after the challenge were related to morphologic changes within and on the surface of the nasal mucosa. Cell samples were obtained daily prior to challenge from the nasal mucosa using mucosal imprints on plastic strips, brush samplings from the nasal mucosa, and nasal lavage. For light microscopy, the cellular material obtained by brushing and nasal lavage were cytocentrifuged onto object slides. Histamine was measured in the cell pellets that were obtained using the lavage and brush procedures as well as in the lavage supernatant fluid. Four symptoms (sneezes, itching, secretion, and blockage) were recorded and expressed individually as well as in the form of a composite symptom score. Nasal blockage was measured using a nasal peak flow meter. The patients displayed an increase in nasal symptoms after the allergen challenge, which was further increased between Days 2 to 7 (p less than 0.05). The light microscopic evaluation of the lavage revealed an immediate increase in eosinophils from 2.3 to 13.1% and was maintained on the same level throughout the period of challenges. A similar increase was noted in the brush specimens, and a strong correlation was obtained between these two methods of sampling.(ABSTRACT TRUNCATED AT 250 WORDS)