Pollen from grasses and trees can trigger allergic rhinitis (AR), where the symptoms and associated consequences can negatively affect quality of life (QoL). The Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) is frequently used in clinical trials of AR to assess QoL. To help interpret RQLQ data, the minimal important difference (MID) can be used to assess whether a mean difference in QoL between treatment groups is clinically meaningful. In seasonal allergy, an MID differs according to the allergen, pollen exposure, symptom severity, patient age and treatment; the same MID cannot be applied to all scenarios.

Using data from four Phase III clinical trials of SQ sublingual immunotherapy-tablets in adults with moderate-to- severe allergy, betweengroup MIDs were derived for the RQLQ in grass pollen allergy (during the peak [n = 501] and entire [n = 514] pollen seasons), and in tree pollen allergy (during the birch [n = 516] and tree [n = 518] pollen seasons), using anchor-based methodology, supported by distribution based methods.

For grass pollen allergy, anchor-based derived between-group MIDs were 0.22 for the entire pollen season (n = 343) and 0.10 for the peak pollen season (n = 335). For tree pollen allergy, anchor-based derived between-group MIDs were 0.26 for the tree pollen season (n = 306) and 0.16 for the birch pollen season (n = 305) (representative of peak season). Distribution-based derived MIDs were supportive of the anchor-based values.

This analysis has derived between-group MIDs specific to the trial populations evaluated and to the conditions under which the data were obtained, and highlights the need for a range of MIDs to reflect the unique nature of seasonal allergic disease.

For young children with peanut allergy, dietary avoidance is the current standard of care. We aimed to assess whether peanut oral immunotherapy can induce desensitisation (an increased allergic reaction threshold while on therapy) or remission (a state of non-responsiveness after discontinuation of immunotherapy) in this population.

We did a randomised, double-blind, placebo-controlled study in five US academic medical centres. Eligible participants were children aged 12 to younger than 48 months who were reactive to 500 mg or less of peanut protein during a double-blind, placebo-controlled food challenge (DBPCFC). Participants were randomly assigned by use of a computer, in a 2:1 allocation ratio, to receive peanut oral immunotherapy or placebo for 134 weeks (2000 mg peanut protein per day) followed by 26 weeks of avoidance, with participants and study staff and investigators masked to group treatment assignment. The primary outcome was desensitisation at the end of treatment (week 134), and remission after avoidance (week 160), as the key secondary outcome, were assessed by DBPCFC to 5000 mg in the intention-to-treat population. Safety and immunological parameters were assessed in the same population. This trial is registered on ClinicalTrials.gov, NCT03345160.

Between Aug 13, 2013, and Oct 1, 2015, 146 children, with a median age of 39·3 months (IQR 30·8–44·7), were randomly assigned to receive peanut oral immunotherapy (96 participants) or placebo (50 participants). At week 134, 68 (71%, 95% CI 61–80) of 96 participants who received peanut oral immunotherapy compared with one (2%, 0·05–11) of 50 who received placebo met the primary outcome of desensitisation (risk difference [RD] 69%, 95% CI 59–79; p<0·0001). The median cumulative tolerated dose during the week 134 DBPCFC was 5005 mg (IQR 3755–5005) for peanut oral immunotherapy versus 5 mg (0–105) for placebo (p<0·0001). After avoidance, 20 (21%, 95% CI 13–30) of 96 participants receiving peanut oral immunotherapy compared with one (2%, 0·05–11) of 50 receiving placebo met remission criteria (RD 19%, 95% CI 10–28; p=0·0021). The median cumulative tolerated dose during the week 160 DBPCFC was 755 mg (IQR 0–2755) for peanut oral immunotherapy and 0 mg (0–55) for placebo (p<0·0001). A significant proportion of participants receiving peanut oral immunotherapy who passed the 5000 mg DBPCFC at week 134 could no longer tolerate 5000 mg at week 160 (p<0·001). The participant receiving placebo who was desensitised at week 134 also achieved remission at week 160. Compared with placebo, peanut oral immunotherapy decreased peanut-specific and Ara h2-specific IgE, skin prick test, and basophil activation, and increased peanut-specific and Ara h2-specific IgG4 at weeks 134 and 160. By use of multivariable regression analysis of participants receiving peanut oral immunotherapy, younger age and lower baseline peanut-specific IgE was predictive of remission. Most participants (98% with peanut oral immunotherapy vs 80% with placebo) had at least one oral immunotherapy dosing reaction, predominantly mild to moderate and occurring more frequently in participants receiving peanut oral immunotherapy. 35 oral immunotherapy dosing events with moderate symptoms were treated with epinephrine in 21 participants receiving peanut oral immunotherapy.

In children with a peanut allergy, initiation of peanut oral immunotherapy before age 4 years was associated with an increase in both desensitisation and remission. Development of remission correlated with immunological biomarkers. The outcomes suggest a window of opportunity at a young age for intervention to induce remission of peanut allergy.

Allergen immunotherapy is effective for the treatment of allergic rhinitis, allergic asthma and Hymenoptera venom allergy. In view of potential side effects, cost, and the necessary patient commitment, an important question is whether allergen immunotherapy provides persistent clinical benefits after treatment discontinuation. Here we appraise the existing evidence for long-term effects of both subcutaneous and sublingual immunotherapy in terms of clinical efficacy, immune mechanisms, prevention of asthma development and prevention of new allergen sensitisations. Evidence from large, randomised, double-blind, placebo controlled clinical trials that include a followup phase after treatment cessation demonstrate long term efficacy. The data strongly support recommendations in international guidelines that both sublingual and subcutaneous immunotherapy should be continued for a minimum of 3 years to achieve disease modification and long-term tolerance. Grass pollen immunotherapy for seasonal rhinitis may inhibit the onset of asthma symptoms and requirements for asthma medication. Whether early intervention in infancy with mite sublingual immunotherapy may prevent asthma remains to be tested.

There is substantial interest in immunotherapy and biologicals in IgE-mediated food allergy.

We searched six databases for randomized controlled trials about immunotherapy alone or with biologicals (to April 2021) or biological monotherapy (toSeptember 2021) in food allergy confirmed by oral food challenge. We pooled the data using random-effects meta-analysis.

We included 36 trials about immunotherapy with 2126 mainly child participants. Oral immunotherapy increased tolerance whilst on therapy for peanut (RR 9.9, 95% CI 4.5.–21.4, high certainty); cow's milk (RR 5.7, 1.9–16.7, moderate certainty) and hen's egg allergy (RR 8.9, 4.4–18, moderate certainty). The number needed to treat to increase tolerance to a single dose of 300 mg or 1000 mg peanut protein was 2. Oral immunotherapy did not increase adverse reactions (RR 1.1, 1.0–1.2, low certainty) or severe reactions in peanut allergy (RR 1,6, 0.7–3.5, low certainty), but may increase (mild) adverse reactions in cow's milk (RR 3.9, 2.1–7.5, low certainty) and hen’s egg allergy (RR 7.0, 2.4–19.8, moderate certainty). Epicutaneous immunotherapy increased tolerance whilst on therapy for peanut (RR 2.6, 1.8–3.8, moderate certainty). Results were unclear for other allergies and administration routes. There were too few trials of biologicals alone (3) or with immunotherapy (1) to draw conclusions.

Oral immunotherapy improves tolerance whilst on therapy and is probably safe in peanut, cow's milk and hen's egg allergy. More research is needed about quality of life, cost and biologicals.

If AIT is to be considered as a treatment option for allergic asthma, it must undergo the same developmental steps as other anti-asthmatic drugs. The bronchial allergen challenge model has demonstrated excellent negative predictive value for the development of new therapies for asthma. SCIT appears to have a clinical and significant effect on the early asthmatic response to mite, cat, and birch and grass pollens in children and adults. Use of AIT in asthmatic children is widely practiced but not supported by as strong a level of evidence as in adults. HDM SLIT tablets demonstrate efficacy in asthma exacerbations and other outcomes when used as add-on therapy in adult patients. Using a biologic to improve the patient’s lung functions and asthma control prior to initiating AIT can make unsuitable candidates for AIT into appropriate candidates. Since AIT is a personalized medicine, phenotyping the most suitable patient is necessary. Adults and children field studies have suggested that polysensitized patients with rhinitis and GINA 2 to 4 asthma appear most likely to be good responders. We hypothesized that AIT responders are those who demonstrate a high eosinophilic response to natural or experimental exposure.

Subcutaneous immunotherapy (SCIT) is an effective treatment for children with allergic rhinitis (AR), but its efficacy fluctuates among patients. There are no reliable candidate biomarkers for monitoring and predicting the response to SCIT. The present study aims to identify novel biomarkers for early predicting the efficacy of SCIT in pediatric AR patients based on multiple cytokine profiling.

We prospectively recruited 72 children with house dust mite (HDM)-induced AR who were assigned to receive SCIT. The serum samples were collected and multiple cytokine profiling was conducted by Luminex assay at baseline. All patients were followed-up for 1 year and then categorized into effective and ineffective group based on their efficacy, and levels of 48 selected cytokines were tested and compared between the two groups. The potential cytokines were further validated by enzyme-linked immunosorbent assay (ELISA) in a cohort with 54 responders and 26 non-responders.

Sixty-nine of 72 children completed one-year follow-up schedule with 46 included in effective group and 23 in ineffective group. The results of multiple cytokine profiling showed that 15 cytokines (eotaxin, G-CSF, GM-CSF, IFN-g, IL-12(p40), IL-13, IL- 15, IL-16, IL-4, MIF, MIP-1a, RANTES, SCF, SDF-1a and VEGF) were dysregulated between effective and ineffective group (all P < 0.05). Unadjusted and adjusted multivariate analysis models highlighted that serum eotaxin, IFN-g, IL-4 and MIF levels closely associated with the efficacy of SCIT in pediatric HDM-induced AR patients. In addition, receiver operating characteristic (ROC) curves revealed potential values of these four biomarkers in predicting the response to SCIT. Further ELISA validation results in the cohort of 80 pediatric patients demonstrated that serum eotaxin and IL-4 levels were elevated in responders while IFN-g levels decreased in responders (all P < 0.05). ROC curves demonstrated that serum IL-4 exhibited more reliable accuracy in predicting SCIT effi cacy than eotaxin and IFN-g.

Our discover– validation study suggested that cytokines including IL-4, eotaxin and IFN- g may serve as robust biomarkers for early predicting response of SCIT in children with HDM-induced AR. These results strengthen the evidence that cytokines were associated with the response of SCIT and contributed to understand its underlying therapeutic mechanisms.

Allergic asthma (AA) is a common asthma phenotype, and its diagnosis requires both the demonstration of IgE-sensitization to aeroallergens and the causative role of this sensitization as a major driver of asthma symptoms. Therefore, a bronchial allergen challenge (BAC) would be occasionally required to identify AA patients among atopic asthmatics. Nevertheless, BAC is usually considered a research tool only, with existing protocols being tailored to mild asthmatics and research needs (eg long washout period for inhaled corticosteroids). Consequently, existing BAC protocols are not designed to be performed in moderate-to- severe asthmatics or in clinical practice. The correct diagnosis of AA might help select patients for immunomodulatory therapies. Allergen sublingual immunotherapy is now registered and recommended for controlled or partially controlled patients with house dust mite-driven AA and with FEV1 ≥ 70%. Allergen avoidance is costly and difficult to implement for the management of AA, so the proper selection of patients is also beneficial. In this position paper, the EAACI Task Force proposes a methodology for clinical BAC that would need to be validated in future studies. The clinical implementation of BAC could ultimately translate into a better phenotyping of asthmatics in real life, and into a more accurate selection of patients for long-term and costly management pathways.

Allergic respiratory diseases, such as allergic dermatitis, food allergy, allergic rhino conjunctivitis and allergic asthma, are chronic inflammatory diseases with increasing prevalence. Symptoms include such as watery or itchy itching of the mouth, skin, or the eyes, swelling of the face or throat, sneezing, congestion or vomiting, wheezing, shortness of breath and coughing. For allergic asthma, additional symptoms include tightness of chest, cough,wheezing, and reversible airflow limitation. These symptoms can be triggered by inhalation of allergens such as food allergens or airborne allergens such as those from tree- or grass pollen and house dust mites. Pharmacological intervention in allergic disease includes the use of antihistamines, immune suppressive drugs and in case of asthma, the use of (long acting) beta-agonists for relaxation of the constricted airways. These treatment options merely suppress symptoms and do not cure the disease. Allergen immunotherapy (AIT), in contrast, has the capacity of inducing long-term tolerance, with symptom relief persisting decennia after discontinuation of treatment, despite recurrent re exposure to the allergen. However, AIT is not effective for all allergic disorders, and treatment for several years is required to obtain long-term protection. Moreover, some forms of AIT have safety concerns, with risk of mild to severe allergic reactions. To improve safety and efficacy of AIT, the underlying mechanisms have been studied extensively in the clinic as well as in experimental models of allergic airway inflammation. Despite more than a century of clinical experience and a vast body of experimental and translational studies into the immunological and cellular mechanisms underpinning its therapeutic potential, AIT is still not implemented in routine clinical care for allergic asthma. This review provides an overview of the substantial developments that contribute to our knowledge of the pathogenesis of allergic airway diseases, the mechanism of action of AIT, its treatment routes and schedules, the standardization of extracts and use of adjuvantia. Moreover, the main conclusions from experimental models of AIT with regard to the safety and effectiveness of the treatment are summarized, and future directions for further improvements are outlined. AIT urgently requires further improvements in order to increase its efficiency and shorten the treatment duration while remaining safe and costeffective.

Allergic respiratory diseases, such as asthma and allergic rhinitis, are global health issues and have had an increasing prevalence in the last decades. Allergen-specific immunotherapy (AIT) is the only curative treatment for allergic rhinitis and asthma, as it has a disease-modifying effect. AIT is generally administered by two routes: subcutaneous (SCIT) and sublingual immunotherapy (SLIT). Local side effects are common, but usually well-tolerated and self-limited. However, systemic side effects are rare, and associated with uncontrolled asthma and bronchial obstruction, or related to errors in administration. Physicians should constantly assess potential risk factors for not only reporting systemic reactions and fatalities but also implementing other therapies to improve AIT safety. This paper highlights recent evidence on local and systemic reactions related to SCIT and SLIT in children.

Oral immunotherapy (OIT) is a treatment option for patients with milk, egg, and peanut allergy, but data on the efficacy and safety of cashew OIT are limited.

A cohort of 50 cashew-allergic patients aged ≥4 years, who were consecutively enrolled into cashew OIT (target dose 4000 mg protein) between 4/2016 and 12/2019. Fifteen cashew-allergic patients who continued cashew elimination served as observational controls. Co-allergy to pistachio and walnut was determined. Full desensitization rate and associated immunological changes in both groups were compared. Patients fully desensitized to cashew were instructed to consume a dose of 1200 mg cashew protein for 6 months and were then challenged to a full dose. Patients with co-allergy to pistachio or walnut were challenged to the respective nut.

Forty-four of 50 OIT-treated patients (88%) compared to 0% in controls tolerated a dose of 4000 mg cashew protein at the end of the study (odds ratio 8.3, 95% CI 3.9–17.7, p < 0.001). An additional three patients were desensitized to 1200 mg cashew protein, and three patients stopped treatment. Three patients (6%) were treated with injectable epinephrine for home reactions. Desensitized patients had decreased SPT, sIgE, basophil reactivity, and increased sIgG4, following treatment. Following cashew desensitization, all pistachio (n = 35) and four of eight walnut co-allergic patients were cross desensitized to the respective nut. All (n = 44) patients consuming a low cashew dose for ≥6 months following desensitization passed a full-dose cashew OFC.

Cashew OIT desensitizes most cashew-allergic patients and cross desensitizes to pistachio. Safety is similar to OIT for other foods.