Double-blind placebo-controlled evaluation of sublingual-swallow immunotherapy with standardized Parietaria judaica extract in children with allergicrhinoconjunctivitis

Background: Sublingual-swallow immunotherapy was recently recognized in the World Health Organization Position Paper (Allergen immunotherapy: therapeu tic vaccines for allergic diseases) "as a viable alternative to parenteral injection therapy to treat allergic diseases" in adults. More controlled st udies were required to assess the efficacy and safety of this treatment in children. Objective: This study was carried out to assess the clinical efficacy and s afety profile of sublingual-swallow immunotherapy with high-dose allergen i n children with allergies. Methods: We used a double-blind placebo-controlled design. Forty-one childr en with Parietaria-induced rhinoconjunctivitis were randomized to receive s ublingual standardized Parietaria judaica extract (n = 20) or placebo (n = 21) for 2 years. The cumulative dose of allergen was 375 times higher than that used in parenteral immunotherapy and the cumulative dose of Par j 1 ma jor allergen was 52.5 mg over 2 years. The main efficacy assessment criteri a were symptoms and rescue medication scores recorded on the patients' diar y cards, Secondary criteria were changes in skin and conjunctival specific reactivity as well as blood parameters, analyzed after 1 and 2 years of imm unotherapy: The safety of the treatment was assessed by evaluating the freq uency and severity of adverse effects. Results: A significant reduction in rhinitis symptoms was observed in the a ctive treatment group during the second season (P = .02), with no differenc e in medication scores. A significant decrease in skin reactivity (P = .002 after 2 years of treatment) and an increase in the threshold dose for conj unctival allergen provocation test (P = .02) were observed in the active tr eatment group compared with the group receiving placebo, A significant incr ease in specific IgG(4) levels (P = .02) was also observed in the active gr oup. Immunotherapy was well tolerated. Conclusion: Sublingual-swallow immunotherapy in Parietaria-allergic childre n provided a clinical benefit and a decreased specific reactivity to the al lergen, The safety profile of this treatment, which constitutes an importan t issue, indicated good tolerance and compliance.