This study was carried out to determine the concentrations of
eosinophil cationic protein (ECP) and
tryptase in the nasal lavage fluid (NLF) of 24 children (C) with grass pollen
rhinitis as well as
rhinitis symptoms before and after nasal provocation tests with or without a
levocabastine (anti-H1 topical
antihistamine) pretreatment. All C were monosensitized to grasses only. Twelve patients (Active Group = AG) were tested with a nasal provocation test with grass pollen (NPT) carried out by the insufflation of increasingly higher doses of an allergenic extract
powder, while the other 12 patients (Placebo Group = PG) underwent just a nasal provocation test with
lactose (placebo) (NPTp). The prechallenge NLF, obtained both before (C) and after (AG)
levocabastine pretreatment, was compared to that obtained after periods of 2 and 24 hours postchallenge. In the AG, before and after
levocabastine pretreatment, the
tryptase concentrations had not significantly increased, whereas the ECP concentrations were found to be significantly higher (p < 0.05) in just the 24-hour postchallenge samples. In the PG the
rhinitis symptoms were not induced by the NPTp and there was no significant change in either ECP or
tryptase concentrations. In the AG a
levocabastine pretreatment induced a significant increase (p < 0.05) in the cumulative
allergen doses administered by the NPT. There was a reduction of the nasal symptoms in 7 patients, while in 3 subjects there was only a slight improvement, but in 2 subjects no effect was encountered. In conclusion this study shows that a
levocabastine pretreatment before an NPT in patients with grass pollen
rhinitis, outside the grass pollen season, induces a significant increase in the cumulative
allergen doses (administered by the NPT) which provoked
rhinitis symptoms but is not able to demonstrate any significant reduction in the ECP concentrations of the NLF.