Intranasal immunotherapy with Dermatophagoides extract: in vivo and in vitro results of a double-blind placebo-controlled trial.

Intranasal immunotherapy (IT) has been proposed as a means to induce an effective immunity of the nasal mucosa in patients with allergic rhinitis, avoiding systemic side effects. In the present study 20 individuals with chronic allergic rhinitis, and skin prick test reactive to Dermatophagoides pteronyssinus (DP) only, were randomized and subjected to a three months' double-blind placebo-controlled trial of intranasal IT with DP extract. All patients received also sodium cromoglycate as pre-medication. Before and at the end of the treatment the patients performed specific nasal provocation tests, and samples of serum and nasal secretions were collected to measure total and specific IgE, levels of eosinophil cationic protein (ECP), and mast-cell-derived tryptase. A clinical score was computed by the symptoms indicated by the patients. The clinical score did not change in the two groups after the treatment, whereas a decrease in nasal reactivity was observed. Total IgE increased only in secretions from placebo-treated patients, but were not modified in sera. IgE to DP in sera and nasal secretions did not change significantly. Tryptase levels in nasal secretions decreased in both groups, while ECP was unchanged after IT. Serum ECP levels decreased more in actively treated patients than in the placebo group. The data suggest that changes of IgE and inflammatory mediators may be affected by the use of sodium cromoglycate in both groups, but some parameters change early in different directions in IT- and placebo-treated groups.