Effect of anti-immunoglobulin E on nasal inflammation in patients with seasonal allergic rhinoconjunctivitis

Background: Binding of allergens to IgE on mast cells and basophils causes release of inflammatory mediators in nasal secretions. Objective: The combined effect of specific immunotherapy (SIT) and omalizumab, a humanized monoclonal anti-IgE antibody, on release of eosinophilic cationic protein (ECP), tryptase, IL-6, and IL-8 in nasal secretion was evaluated. Methods: Two hundred and twenty five children (aged 6-17 years) with a history of seasonal allergic rhinoconjunctivitis induced by birch and grass pollen were randomized into four groups: either birch- or grass-pollen SIT in combination with either anti-IgE or placebo. Complete sets of nasal secretion samples before treatment Visit 1 (V1), during birch- (V2) and grass (V3)-pollen season and after the pollen season (V4) were collected from 53 patients. Results: A significant reduction in tryptase only was seen in the anti-IgE-treated group at V2 (P < 0.05) and V4 (P < 0.05) compared with the placebo group. During the pollen season, patients with placebo showed an increase of ECP compared with baseline (V2: + 30.3 μg/L; V3: + 134.2 μg/L, P < 0.005; V4: + 79.0 μg/L, P < 0.05), and stable levels of tryptase, IL-6 and IL-8. Treatment with anti-IgE resulted in stable ECP values and a significant decrease of tryptase compared with V1 (baseline): V2: - 80.0 μg/L (P < 0.05); V3: - 56.3 μg/L, which persisted after the pollen season with V4: - 71.6 μg/L (P < 0.05). After the pollen season, a decrease of IL-6 was observed in both groups (V4 placebo group: - 37.5 ng/L; V4 anti-IgE group: - 42.9 ng/L, P < 0.01). Conclusion: The combination of SIT and anti-IgE is associated with prevention of nasal ECP increase and decreased tryptase levels in nasal secretions.