DOUBLE-BLIND, PLACEBO-CONTROLLED CLINICAL-TRIAL OF PRESEASONAL TREATMENT WITH ALLERGENIC EXTRACTS OF OLEA-EUROPAEA POLLEN ADMINISTERED SUBLINGUALLY

In a double-blind, placebo-controlled, pilot clinical trial we evaluat ed the clinical efficacy and safety of immunotherapy (IT) with an extr act of the pollen of the free Olea europaea administered sublingually. The parameters tested were symptom score, dose-response bioassay of s kin prick test and specific IgE and IgG, and the absolute value at a s ingle serum dilution of each IgG subclass. Fifteen patients allergic t o this pollen with symptomatology of rhinitis and/or rhinoconjunctivit is were randomly allocated to the placebo group (6 patients) or to the extract group (9 patients). Immunotherapy was administered in a short preseasonal period of time, practically no side effects being recorde d. The group of patients treated, with extract presented a slightly lo wer incidence (0.05 < p < 0.1) of nasal symptoms of sneezing and obstr uction, and, more importantly, developed less dyspnea (p < 0.05) than the group treated with placebo, suggesting that IT can act as prophyla xis for the development of bronchial symptoms. No differences were obs erved in the immunological determinations. Differences in skin tests b etween the two groups displayed a slight significance (0.05 < p < 0.1) at the end of the trial; hence, a higher concentration of the allerge n was needed in the group treated with extract to induce the same whea l as in the placebo group. In both groups the size of the wheal showed a time-dependent variation, which was dependent on the time of the ye ar and independent of the type of treatment received, indicating a sig nificant modification in the in;vivo skin response to allergen challen ge, demonstrated by a shift in the kinetics of allergen-ligand binding (slope) and in