Allergen immunotherapy for the prevention of allergy: A systematic review and meta-analysis.
Topic: Immunotherapy

There is a need to establish the effectiveness, cost-effectiveness, and safety of allergen immunotherapy (AIT) for the prevention of allergic disease.

PICO
Population: Patients with allergic disease or at risk of developing allergies
Intervention: Allergen immunotherapy (AIT) for the prevention of allergic disease
Comparison: Standard care or placebo
Outcomes: Effectiveness, cost-effectiveness, and safety of AIT for allergy prevention

Included studies:
title: Immunotherapy with a standardized Dermatophagoides pteronyssinus extract. VI. Specific immunotherapy prevents the onset of new sensitizations in children.
abstract: The natural history of allergic sensitization is complex and poorly understood. A prospective nonrandomized study was carried out in a population of asthmatic children younger than 6 years of age whose only allergic sensitivity was to house dust mites (HDMs).
title: Benefits of immunotherapy with a standardized Dermatophagoides pteronyssinus extract in asthmatic children: a three-year prospective study.
abstract: Although widely practiced for over 80 years, the role of specific immunotherapy (SIT) in pediatric asthma treatment is still controversial. We assessed the effects of a 3-year period of subcutaneous administration of a standardized preparation of Dermatophagoides pteronyssinus (D pt) on the respiratory health in a group of asthmatic children monosensitized to house dust mite (HDM).
title: Prevention of new sensitizations by specific immunotherapy in children with rhinitis and/or asthma monosensitized to house dust mite.
abstract: Previous studies have suggested that single-allergen-specific immunotherapy (SIT) may prevent sensitization to other airborne allergens in monosensitized children. We aimed to assess the prevention of new sensitizations in monosensitized children treated with single-allergen SIT injections in comparison with monosensitized patients given appropriate pharmacologic treatment for their disease.
title: Preventive effects of sublingual immunotherapy in childhood: an open randomized controlled study.
abstract: Sublingual immunotherapy (SLIT) has been proved to be effective in allergic rhinitis and asthma, but there are few data on its preventive effects, especially in children.
title: Allergy immunotherapy for allergic rhinitis effectively prevents asthma: Results from a large retrospective cohort study.
abstract: Allergic rhinitis (AR) is a main risk factor for the development of asthma. Two randomized open-label trials indicated that allergy immunotherapy (AIT) prevents the onset of asthma in patients with AR. However, these trials have methodological limitations, and it is unclear to what extent this experimental efficacy translates into clinical effectiveness.
title: Coseasonal sublingual immunotherapy reduces the development of asthma in children with allergic rhinoconjunctivitis.
abstract: We wondered whether short-term coseasonal sublingual immunotherapy (SLIT) can reduce the development of asthma in children with hay fever in an open randomized study.
title: Specific immunotherapy is effective in the prevention of new sensitivities.
abstract: Allergen specific immunotherapy is the only specific and curative approach in the treatment of IgE-mediated allergic diseases such as bronchial asthma and allergic rhinitis. The safety and clinical efficacy of this treatment are well documented but data on the prevention of new sensitizations remain scarce.
title: Pollen immunotherapy reduces the development of asthma in children with seasonal rhinoconjunctivitis (the PAT-study).
abstract: Children with allergic rhinitis are likely to develop asthma.
title: Long-term immunologic effects of broad-spectrum aeroallergen immunotherapy.
abstract: Limited data exist regarding extended, long-term immunologic effects of immunotherapy in polysensitized individuals. To study possible long-term effects, skin tests and specific IgE levels were obtained from subjects who had previously received broad-spectrum aeroallergen immunotherapy years before.
title: Design and recruitment for the GAP trial, investigating the preventive effect on asthma development of an SQ-standardized grass allergy immunotherapy tablet in children with grass pollen-induced allergic rhinoconjunctivitis.
abstract: Allergic rhinoconjunctivitis is a risk factor for asthma development. Treating the underlying allergy may represent an attractive method of asthma prevention. No regulatory guidance exists in this area, and, to our knowledge, no clinical investigations meeting modern regulatory standards have been published.
title: Long-lasting effect of sublingual immunotherapy in children with asthma due to house dust mite: a 10-year prospective study.
abstract: Subcutaneous immunotherapy for respiratory allergy has shown a long-lasting efficacy after its discontinuation, whereas this evidence is still lacking for sublingual immunotherapy, despite the fact that it is widely used.
title: Effects of specific immunotherapy in allergic rhinitic individuals with bronchial hyperresponsiveness.
abstract: Allergic rhinitis can be associated with bronchial hyperresponsiveness (BHR), and carries an increased risk for the development of asthma. The aim of this study was to evaluate the ability of specific immunotherapy (SIT) to reduce the progression of allergic rhinitis to asthma and prevent the associated increase in BHR. Forty-four subjects monosensitized to Dermatophagoides pteronyssinus, with perennial rhinitis and BHR to methacholine, were randomly assigned to receive SIT or placebo in a double-blind study conducted over a period of 2 yr. After 1 yr of treatment, a 2.88-fold increase in the provocative dose of methacholine producing a 20% decrease in FEV(1) (PD(20)FEV(1)) was recorded in the SIT-treated group (95% confidence interval [CI]: 3.98- to 2.09-fold; p < 0.001), with a further increase to fourfold at the end of Year 2 (95% CI: 2.9- to 5.7-fold; p < 0.001). At the end of the study, the methacholine PD(20)FEV(1) was within the normal range in 50% of treated subjects (p < 0.0001), and was significantly higher in this group than in the group receiving placebo (p < 0.0001). In contrast, no changes in methacholine PD(20)FEV(1) were found in the placebo group throughout the study. Although 9% of subjects given placebo developed asthma, none of those treated with SIT did. This study suggests that SIT, when administered to carefully selected, monosensitized patients with perennial allergic rhinitis, reduces airway responsiveness in subjects with rhinitis, and may be an appropriate prophylactic treatment for rhinitic patients with hyperreactive airways.
title: Immunological parameters in prophylactic sublingual immunotherapy in asymptomatic subjects sensitized to Japanese cedar pollen.
abstract: This study aims to examine the immunological parameters, focusing IL-10 productivity, in prophylactic sublingual immunotherapy (SLIT) in asymptomatic subjects sensitized to Japanese cedar pollen (JCP).
title: [Efficacy evaluation of standardized dust mite allergen specific immunotherapy to patients of allergic rhinitis].
abstract: To evaluate the efficacy of mite allergen specific immunotherapy (SIT) to patients of allergic rhinitis.
title: A randomized, controlled study of specific immunotherapy in monosensitized subjects with seasonal rhinitis: effect on bronchial hyperresponsiveness, sputum inflammatory markers and development of asthma symptoms.
abstract: Allergic rhinitis is often associated with bronchial hyperresponsiveness (BHR) and airway inflammation, and it seems to be an important risk factor for the development of asthma. Specific immunotherapy (SIT) reduces symptoms and medication requirements in subjects with allergic rhinitis, but the mechanisms by which SIT promotes these beneficial effects are less clear. We have investigated the effects of Parietaria-SIT on rhinitis symptoms, BHR to inhaled methacholine, eosinophilic inflammation and cytokine production (interferon gamma and interleukin-4) in the sputum. The effect on asthma progression was also examined. Thirty non-asthmatic subjects with seasonal rhinitis and monosensitized to Parietaria judaica participated in a randomized, double-blind, placebo-controlled, parallel group study. Participants were randomly assigned to receive injections of a Parietaria pollen vaccine (n = 15) or matched placebo injections (n = 15) in a rapid updosing cluster regimen for 7 weeks, followed by monthly injections for 34 months. Throughout the 3-year study we collected data on symptoms and medication score, airway responsiveness to methacholine, eosinophilia and soluble cytokines in sputum, followed by a complete evaluation of the clinical course of atopy. Hay fever symptom and medication scores were well controlled by SIT. By the end of the study, in the placebo group, symptom and medication scores significantly increased by a median (interquartile range) of 121% (15-280%) and 263% (0-4400%) respectively (p < 0.01), whereas no significant difference was observed in the SIT group. We found no significant changes in the sputum parameters and methacholine PC15 values in both groups throughout the study. By the end of the investigation, a total of 9 out of 29 participants developed asthma symptoms; of these, seven (47%) belonged to the placebo group, whereas only 2 (14%) to the SIT-treated group (p = 0.056). In conclusion, Parietaria-SIT is effective in controlling hay fever symptoms and rescue medications, but no changes in the BHR to methacholine or sputum eosinophilia were observed. Moreover, Parietaria-SIT appears to prevent the natural progression of allergic rhinitis to asthma, suggesting that SIT should be considered earlier in the management of this condition.
title: Randomized controlled open study of sublingual immunotherapy for respiratory allergy in real-life: clinical efficacy and more.
abstract: Some aspects of sublingual immunotherapy (SLIT) still need to be addressed: magnitude of the clinical efficacy, effect on the bronchial hyperreactivity adherence to treatment, preventive effect. We attempted to clarify these points in a randomized open, controlled, two parallel group study in a real-life setting.
title: Preventive sublingual immunotherapy in preschool children: first evidence for safety and pro-tolerogenic effects.
abstract: Prevention of new IgE sensitizations has been described during allergen-specific immunotherapy. However, prospective data using a preventive approach in very young children who would benefit most are missing. We initiated a prospective pilot study investigating the safety, immunomodulatory, and sensitization-preventive effect of sublingual immunotherapy (SLIT) in mono/oligoclonally sensitized, clinically asymptomatic children 2-5 yr of age.
title: Randomized controlled trial of primary prevention of atopy using house dust mite allergen oral immunotherapy in early childhood.
abstract: Children born to atopic parents are at increased risk of sensitization to environmental allergens.