Rhinitis symptoms caused by grass pollen are associated with elevated basophile allergen sensitivity and a larger grass-specific immunoglobulin E fraction

Background The mechanisms responsible for the difference between clinically irrelevant IgE-sensitization and allergic rhinitis are not fully understood. Objective We evaluated the humoral and cellular mechanisms that may be associated with the presence of allergic rhinitis symptoms. Methods We selected 26 subjects with positive grass pollen skin tests and IgE antibodies to Timothy (g6) and the major grass allergens rPhl p 1, 5b. Fourteen of those patients reported a history of allergic rhinitis. During winter, we performed a grass pollen CD63 basophile activation test using four log allergen concentrations, followed by a grass nasal provocation test (NPT). We obtained symptom scores in the subsequent pollination season. Results We showed that subjects with a positive NPT have significantly higher CD63 basophile grass pollen responsiveness than NPT-negative subjects, preferably at submaximal allergen concentrations, which represent cellular sensitivity. Moreover, basophile sensitivity positively correlated with the size of the grass-specific IgE fraction in relation to total IgE, and it was highly predictive of allergic rhinitis symptoms in the following pollination season. Conclusion and Clinical Relevance Allergic rhinitis symptoms are significantly associated with allergen-specific basophile sensitivity. In vitro evaluation of basophile sensitivity should prove useful for distinguishing clinical phenotype of allergic sensitization.