ABSTRACT
The use of allergen immunotherapy (AIT) in Brazil has specific regional conditions owing to the pattern of allergen sensitization, as well as to genetic, socioeconomic, and cultural characteristics. This review article aims to discuss the clinical practice of AIT by the subcutaneous or sublingual route in Brazil, addressing the possibilities of transition between these forms of administration. A systematic review using the PubMed and Cochrane databases was performed, and the websites of major allergy and immunology organizations were consulted. Knowledge of the mechanism of action of subcutaneous immunotherapy and sublingual immunotherapy, together with Brazilian real-life experience, allowed us to establish recommendations regarding switching routes of AIT administration in selected cases. Careful analysis of each clinical situation is necessary to perform the transition between subcutaneous and sublingual allergen immunotherapy.
ABSTRACT
Background: Allergen Immunotherapy (AIT) represents one of the pillars in the treatment of allergic diseases. AIT is the only therapeutic strategy with curative potential, promoting the reduction of drug use and long-term symptom control even after the end of the treatment. The European Academy of Allergy, Asthma and Immunology (EAACI) guidelines, position papers of World Allergy Organization (WAO), and the US Practice Parameters are the leading official documents that set scientific standard for the use of AIT in the world. The use of AIT in Brazil has specific regional conditions due to the pattern of allergen sensitization, as well as genetic, socioeconomic, and cultural characteristics, climate conditions, and the availability of allergenic extracts. The most prevalent house dust mites are Dermatophagoides pteronyssinus, Dermatophagoides farinae and their allergens have the highest clinical relevance. Blomia tropicalis is also very frequent. This position paper has been prepared by the Brazilian Association of Allergy and Clinical Immunology (ASBAI) Taskforce on AIT for respiratory allergy and Hymenoptera venom allergy. Objective: According to the current scientific literature adapted to the Brazilian reality, this position paper aims to establish the main recommendations for the good clinical practice parameters for AIT in Brazil. Methods: A systematic review using the Pub Med and Cochrane databases was performed, and the websites of major allergy and immunology organizations were consulted. The research was limited to English language literature and was conducted between March 30, 2002, and March 30, 2022. The terms used for the research were: Allergen Immunotherapy, sublingual immunotherapy (SLIT), subcutaneous immunotherapy (SCIT), venom-specific immunotherapy (VIT), and allergen extract. Results: The several recommendations that establish the clinical practices for AIT recommended by the main Allergy, Asthma and Immunology world organizations were analyzed and adapted to the Brazilian situation. Conclusion: This position paper establishes the main recommendations for the effective clinical practice of AIT in Brazil, using current knowledge of evidence-based medicine and precision medicine.
ABSTRACT
BACKGROUND: Allergen immunotherapy (AIT) has a longstanding history and still remains the only disease-changing treatment for allergic rhinitis and asthma. Over the years 2 different schools have developed their strategies: the United States (US) and the European. Allergen extracts available in these regions are adapted to local practice. In other parts of the world, extracts from both regions and local ones are commercialized, as in Mexico. Here, local experts developed a national AIT guideline (GUIMIT 2019) searching for compromises between both schools. METHODS: Using ADAPTE methodology for transculturizing guidelines and AGREE-II for evaluating guideline quality, GUIMIT selected 3 high-quality Main Reference Guidelines (MRGs): the European Academy of Allergy, Asthma and Immunology (EAACI) guideines, the S2k guideline of various German-speaking medical societies (2014), and the US Practice Parameters on Allergen Immunotherapy 2011. We formulated clinical questions and based responses on the fused evidence available in the MRGs, combined with local possibilities, patient's preference, and costs. We came across several issues on which the MRGs disagreed. These are presented here along with arguments of GUIMIT members to resolve them. GUIMIT (for a complete English version, Supplementary data) concluded the following. RESULTS: Related to the diagnosis of IgE-mediated respiratory allergy, apart from skin prick testing complementary tests (challenges, in vitro testing and molecular such as species-specific allergens) might be useful in selected cases to inform AIT composition. AIT is indicated in allergic rhinitis and suggested in allergic asthma (once controlled) and IgE-mediated atopic dermatitis. Concerning the correct subcutaneous AIT dose for compounding vials according to the US school: dosing tables and formula are given; up to 4 non-related allergens can be mixed, refraining from mixing high with low protease extracts. When using European extracts: the manufacturer's indications should be followed; in multi-allergic patients 2 simultaneous injections can be given (100% consensus); mixing is discouraged. In Mexico only allergoid tablets are available; based on doses used in all sublingual immunotherapy (SLIT) publications referenced in MRGs, GUIMIT suggests a probable effective dose related to subcutaneous immunotherapy (SCIT) might be: 50-200% of the monthly SCIT dose given daily, maximum mixing 4 allergens. Also, a table with practical suggestions on non-evidence-existing issues, developed with a simplified Delphi method, is added. Finally, dissemination and implementation of guidelines is briefly discussed, explaining how we used online tools for this in Mexico. CONCLUSIONS: Countries where European and American AIT extracts are available should adjust AIT according to which school is followed.
ABSTRACT
BACKGROUND: Sensitization to Blomia tropicalis (Bt) is very frequent in the tropics, and particularly in Cuba, being a significant cause of allergic asthma. Allergen immunotherapy (AIT) with Bt can be a therapeutic option, however, placebo-controlled clinical trials have not been reported. OBJECTIVE: To assess the therapeutic effect and safety of AIT for asthma using a standardized allergen vaccine of B. tropicalis by subcutaneous route, in allergic asthmatic patients exposed and sensitized to this mite species. METHODS: A double-blind, placebo-controlled Phase II trial was conducted in 35 adults (18 with treatment and 17 with placebo), with mild to moderate asthma, predominantly sensitized to Bt. AIT was administered subcutaneously in increasing doses from 4 to 6000 Biological Units using a locally manufactured standardized extract (BIOCEN, Cuba). Patient assessment was performed using symptom-medication score (SMS), peak expiratory flow and skin reactivity relative to Histamine as measured by skin prick test (SPT). RESULTS: The 12-month treatment achieved a significant (p < 0.001) decrease of SMS. Symptom score showed only 41% (CI: 26-61) of placebo values, whereas medication was 34.5% (22.4%-63.3%). Treatment was regarded clinically effective in 67% of patients (OR 32; 95%CI: 17 to 102). The effect size on symptoms and medication was higher than has been reported with equivalent allergen dosages of D. pteronyssinus and D. siboney in Cuban asthmatic patients. Skin reactivity to Bt was also significantly reduced (p = 0.0001), increasing 148-fold the allergen threshold to elicit a positive skin test. This desensitization effect was specific to Bt and did not modify the reactivity to Dermatophagoides. The change of specific skin reactivity was significantly (p < 0.05) correlated to clinical improvement. All adverse events were local with a frequency of 2.4% of injections. CONCLUSIONS: Subcutaneous AIT with Blomia tropicalis was effective and safe in asthmatic adults exposed and sensitized to this mite species in a tropical environment. TRIAL REGISTRATION: Cuban Public Registry of Clinical Trials: RPCEC00000026 (WHO International Clinical Trial Registry Platform ICTRP).