In allergic patients with rhinoconjunctivitis (RNC), sublingual immunotherapy (SLIT) is effective in reducing both clinical symptoms and immuno-mediated local inflammatory responses. The study evaluates whether SLIT could reduce upper airway inflammation and improve clinical parameters also in children with rhinoconjunctivitis and asthma from house dust mite sensitization. Ten children with mild to intermittent asthma, monosensitized to house dust mites, received SLIT (Der p 1 monthly dose = 48 microg) for 2 years, in addition to "as needed" pharmacologic treatment. Before (T0) and after treatment (T2), changes were evaluated in (1) nasal eosinophilia, (2) intercellular adhesion molecule (ICAM)-1 expression by nasal epithelial cells, (3) RNC, asthma, and drug-intake scores, assessed by diary card, (4) pulmonary function parameters, and (5) bronchial reactivity to methacholine (MCh).
Results: All children completed the study without side or adverse effects. After the treatment period, we found no modification in nasal eosinophil values in mean fluorescence channel percentages, but a significant downregulation in ICAM-1 expression by nasal epithelial cells [mean (mfc): T0: 13.5 +/- 3.8 mfc; T2:4.6 +/- 0.5 mfc; p = 0.04]. These changes were associated with a reduction in RNC score [median values: T0: 3.4 (1.4-6.2); T2: 1.1 (0.6-2.4) p = 0.012], asthma score [median values: T0: 0.5 (0.4-1.0); T2: 0.3 (0.1-0.5); p = 0.005] and drug-intake score [median values: T0: 4.2 (3.1-5.3); T2: 1.1 (0-3.0); p = 0.005]. These clinical effects were not associated with changes in pulmonary function parameters (p > 0.05), but with improvement in bronchial reactivity to MCh [mean values: T0: 338.8 (91.5-1255.5); T2: 1698.2 (1,110.5-2,597.1); p = 0.02]. To what extent these observations may be related to the natural improvement of respiratory allergy symptoms with age remains to be determined.