Priming of eosinophil adhesion in patients with birch pollen allergy during pollen season: effect of immunotherapy.

The adhesion of eosinophil granulocytes to E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) was investigated before and during birch pollen season in 24 patients allergic to birch pollen who had rhinoconjunctivitis and, in half of the cases, asthma during season. Half of the patients were undergoing specific immunotherapy for birch pollen allergy. Increased adhesion to VCAM-1 and ICAM-1 (p < 0.05) during season as compared with before season was demonstrated by eosinophils of patients in the control group and by eosinophils of the patients without asthma treated with immunotherapy, but not by eosinophils from the immunotherapy-treated patients with asthma. Eosinophils from the control group of patients demonstrated increased cell surface expression of CD18 and CD49d (p < 0.05 and p < 0.01, respectively) during season as compared with before season, and eosinophils from the immunotherapy-treated patients showed increased cell surface expression of CD49d (p < 0.01) during season. Simultaneous measurement of neutrophil adhesion revealed increased adhesion to E-selectin and ICAM-1 (p < 0.01) during season compared with before season in the immunotherapy-treated group of patients. Neutrophils from the control subjects without asthma showed increased adhesion to E-selectin (p < 0.05) during season. In conclusion, eosinophils from patients allergic to birch pollen demonstrated priming of the adhesion to VCAM-1 to ICAM-1 during birch pollen season. Immunotherapy treatment prevented the priming of eosinophil adhesion during pollen season in the patients allergic to birch pollen who had asthma, but not in those without asthma. In contrast, neutrophils from the immunotherapy-treated patients, both with and without asthma, demonstrated priming of the adhesion to E-selectin and ICAM-1 during season. The latter results indicate that immunotherapy, in case of the patients allergic to birch pollen with asthma induced a shift from the production of primarily eosinophil priming agents to primarily neutrophil priming agents, which may be caused by a shift from Th2 to Th1 lymphocytes.