Double‐blind, placebo‐controlled evaluation of sublingual immunotherapy with standardized olive pollen extract in pediatric patients with allergic rhinoconjunctivitis and mild asthma due to olive pollen sensitization

Abstract

For evaluation of the efficacy and the safety of specific sublingual immunotherapy with high allergen dose, 66 children with seasonal asthma, rhinitis, and conjunctivitis due to sensitization to olive pollen were enrolled in a double-blind, randomized, placebo-controlled study between October 1994 and October 1996 in Greece. Thirty-four patients were randomly allocated to the active group, and 32 received placebo. Immunotherapy consisted of olive-allergen extracts (Stallergènes SA) administered sublingually pre- and coseasonally from January to July for 2 consecutive years. Serial concentrations from 1 to 300 IR. were used up to the maintenance dose of 20 drops of 300 IR daily. The cumulative dose for each patient was 300 times higher than in parenteral immunotherapy, and the cumulative dose of the major allergen Ole e 1 was 8.1 mg/2 years. The patients were assessed by clinical parameters (symptom and medication scores from patients' daily diaries) and immunologic measurements (specific IgE, IgG4, eosinophil cationic protein [ECP]) were performed. The actively treated patients had a significantly lower score for dyspnea (P<0.04 during the first season; P<0.03 during the second season). At the pollinic peak during the second year, a lower score of conjunctivitis was recorded (P<0.05) in the actively treated patients. The analysis of intragroup evolution showed that the total score of rhinitis increased significantly during the pollinic peak in the group under placebo, whereas there was no symptomatic peak for the same period in the group under active treatment. However, the difference between the groups was not significant. The medication score did not differ significantly between the groups. Oral steroids were the only variables with a P value near the significance level (P=0.06) in favor of the actively treated group. A significant decrease in skin reactivity was recorded in the active group after 2 years of treatment. No significant variation in specific IgE and IgG4 was detected. A significantly lower level of serum ECP was observed at the pollinic peak in the actively treated patients during the first pollen season (P=0.01), but this was not confirmed the second year when the ECP levels doubled in both groups without correlation to the clinical findings. Tolerance was excellent with only a few minor side-effects reported. In conclusion, high-dose specific sublingual immunotherapy appears to be safe and effective in improving mild seasonal asthma and conjunctivitis linked to olive-pollen sensitization.

Allergen-Specific Immunotherapy for Pediatric Asthma and Rhinoconjunctivitis: A Systematic Review

“…The magnitudes of effect could not be determined in 7 studies. 25,[27][28][29]32,35,36 The risk of bias across these studies was mixed. The strength of evidence is moderate that SLIT decreases medication use.…”

“…25,28 Five studies demonstrated significant improvement in rhinitis/ rhinoconjunctivitis scores with SLIT, compared with placebo, with moderate to strong magnitudes of effect. 33,34,[36][37][38] Four studies did not show significant improvement with SLIT, 25,26,29,32 and 1 of these favored placebo. 26 The strength of evidence is moderate that SLIT improves rhinitis symptoms.…”

“…25,[34][35][36][37] Two placebocontrolled trials of olive and tree mix allergens with medium risk of bias that enrolled 70 and 98 children, respectively, demonstrated moderate to strong magnitude of effect for SLIT. 36,37 One study of dust mite immunotherapy in 58 children, with a low risk of bias and weak magnitude of effect, showed little improvement with SLIT compared with placebo. 34 One study of dust mite allergen with 257 children and a high risk of bias and another study of Parietaria allergen with 30 children and a low risk of bias reported improvement with SLIT, although we could not determine the magnitude of effect.…”

“…[25][26][27][28][29][32][33][34][35][36][37][38] One-half of the studies evaluated dust mite allergens. 25,26,[32][33][34]38 Risk of bias was low in 4 studies, 27,29,32,34 medium in 6 studies, 26,33,[35][36][37][38] and high in 2 studies. 25,28 Five studies demonstrated significant improvement in rhinitis/ rhinoconjunctivitis scores with SLIT, compared with placebo, with moderate to strong magnitudes of effect.…”

“…[22][23][24][25][26][27][28][29]32,33,[35][36][37] Six studies evaluated dust mite allergen. [22][23][24][25][26]32 The placebo-controlled studies demonstrated significant reductions in medication use in the SLIT group relative to the placebo group, with moderate to strong magnitudes of effect in patients with asthma and/or rhinitis.…”