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 I (VI), during birch- (V2) and grass (V3)-pollen season and after the pollen season (W) 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 mug/L; V3: +134.2 mug/L, P<0.005; V4: +79.0 mu g/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 VI (baseline): V2: -80.0 mug/L (P<0.05); V3: -56.3 mu g/L, which persisted after the pollen season with V4: - 71.6 mu g/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.