The placebo (Latin "I will please") effect commonly occurs in clinical trials. The psychological and physiological factors associated with patients' expectations about a treatment's positive and negative effects have yet to be well characterized, although a functional prefrontal cortex and intense bidirectional communication between the central nervous system and the immune system appear to be prerequisites for a placebo effect. The use of placebo raises certain ethical issues, especially if patients in a placebo group are denied an effective treatment for a long period of time. The placebo effect appears to be relatively large (up to 77%, relative to pretreatment scores) in controlled clinical trials of allergen immunotherapy (AIT), such as the pivotal, double-blind, placebo-controlled (DBPC) randomized clinical trials currently required by regulatory authorities worldwide. The European Academy of Allergy and Clinical Immunology (EAACI) therefore initiated a Task Force, in order to better understand the placebo effect in AIT and its specific role in comorbidities, blinding issues, adherence, measurement time points, variability and the natural course of the disease. In this Position Paper, the EAACI Task Force highlights several important topics regarding the placebo effect in AIT such as a) regulatory aspects, b) neuroimmunological and psychological mechanisms, c) placebo effect sizes in AIT trials, d) methodological limitations in AIT trial design and e) potential solutions in future AIT trial design. In conclusion, this Position Paper aims to examine the methodological problem of placebo in AIT from different aspects and also to highlight unmet needs and possible solutions for future trials.

Sensitization to Felis domesticus allergen 1 (Fel d 1) contributes to persistent allergic rhinitis and asthma. Existing treatment options for cat allergy, including allergen immunotherapy (AIT) are only moderately effective, and AIT has limited use due to safety concerns.

To explore the relationship among the pharmaokinteic, clinical, and immunological effects of REGN1908-1909 (anti-Fel d 1 monoclonal antibodies) in patients after treatment.

Patients received REGN1908-1909 (n=36) or placebo (n=37) in a phase 1b study. Fel d 1-induced basophil and IgE-facilitated allergen binding responses were evaluated at baseline and days 8, 29 and 85. Cytokine and chemokine levels in nasal fluids were measured. REGN1908-1909 inhibition of allergen-IgE binding in patient serum was evaluated.

Peak serum drug concentrations were concordant with maximal observed clinical response. The anti-Fel d 1 IgE/cat-dander IgE ratio in pretreatment serum correlated with Total Nasal Symptom Score improvement. The allergen neutralizing capacity of REGN1908-1909 was observed in serum and nasal fluid, and was detected in an inhibition assay. Type-2 cytokines (IL-4, IL-5 and IL-13) and chemokines (CCL17/TARC, CCL5/RANTES) in nasal fluid were inhibited in REGN1908-1909-treated patients compared to placebo (all P < 0.05); IL-13 and IL-5 levels correlated with TNSS improvement. Ex vivo assays demonstrated that REGN1908 and REGN1909 combined was more potent than each alone for inhibiting FcεRI- and FcεRII (CD23)-mediated allergic responses and subsequent T-cell activation.

Single passive dose administration of Fel d 1-neutralizing IgG antibodies improved nasal symptoms in cat-allergic patients, and was underscored by suppression of FcεRI-, FcεRII- and Th2-mediated allergic responses.

Allergen immunotherapy (AIT) is a disease-modifying treatment for some IgE-mediated allergic diseases with the potential to have important preventive effects. Children with allergic rhinitis have a high risk of developing asthma, and treating allergic rhinitis with AIT may interfere with disease progression and prevent onset of asthma. Although the evidence is limited due to relatively few and heterogeneous studies, data nevertheless suggest that AIT has a preventive effect on development of asthma especially in children with rhinitis due to grass pollen allergy. AIT may also affect the development of new sensitizations. Both the degree of sensitization and the specific sensitization pattern may influence future disease severity and development of comorbidities. Hitherto, the indication for AIT for prevention of development of asthma in grass/birch pollen allergic children has been the same as for treatment of allergic rhinitis. Probably, AIT should be applied in the early stage of the allergic disease to have the greatest preventive effect on disease progression. Consequently, in the future, the potential preventive effects should influence the timing of initiating AIT. The window of opportunity to prevent asthma may primarily exist in young children with mild symptoms and a low degree of sensitization.

Sensitization to one or more non-specific lipid transfer proteins (nsLTPs), initially thought to exist mainly in southern Europe, is becoming accepted as a cause of allergic reactions to plant foods across Europe and beyond. The peach nsLTP allergen Pru p 3 is a dominant sensitizing allergen and peaches a common food trigger, although multiple foods can be involved. A frequent feature of reactions is the requirement for a cofactor (exercise, alcohol, non-steroidal anti-inflammatory drugs, Cannabis sativa) to be present for a food to elicit a reaction. The variability in the food and cofactor triggers makes it essential to include an allergy-focused diet and clinical history in the diagnostic workup. Testing on suspected food triggers should also establish whether sensitization to nsLTP is present, using purified or recombinant nsLTP allergens such as Pru p 3. The avoidance of known trigger foods and advice on cofactors is currently the main management for this condition. Studies on immunotherapy are promising, but it is unknown whether such treatments will be useful in populations where Pru p 3 is not the primary sensitizing allergen. Future research should focus on the mechanisms of cofactors, improving diagnostic accuracy and establishing the efficacy of immunotherapy.

Allergen immunotherapy (AIT) is a proven therapeutic option for the treatment of allergic rhinitis and/or asthma. Many international or national practice guidelines have been produced, but the evidence-based method varies and they do not usually propose care pathways. The present paper considers the possible role of mHealth in AIT for allergic rhinitis/asthma. There are no currently available validated biologic biomarkers that can predict AIT success, and mHealth biomarkers have some relevance. In the current paper, the following aspects will be discussed: patient stratification for AIT, symptom medication scores for the follow-up of patients, clinical trials as well as the approach of the European Academy of Allergy and Clinical Immunology.

Long-term efficacy that occurs with allergen immunotherapy of proven value is associated with decreases in IgE-dependent activation of mast cells and tissue eosinophilia. This suppression of type 2 immunity is accompanied by early induction of regulatory T cells, immune deviation in favor of TH1 responses, and induction of local and systemic IgG, IgG4, and IgA antibodies. These "protective" antibodies can inhibit allergen-IgE complex formation and consequent mast cell triggering and IgE-facilitated TH2-cell activation. Recent studies have highlighted the importance of innate responses mediated by type 2 dendritic cells and innate lymphoid cells in allergic inflammation. These cell types are under the regulation of cytokines such as thymic stromal lymphopoietin and IL-33 derived from the respiratory epithelium. Novel subsets of regulatory cells induced by immunotherapy include IL-35-producing regulatory T cells, regulatory B cells, a subset of T follicular cells (TFR cells), and IL-10-producing group 2 innate lymphoid cells. These mechanisms point to biomarkers that require testing for their ability to predict clinical response to immunotherapy and to inform novel approaches for better efficacy, safety, and long-term tolerance.

Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease characterized by severe pruritus and eczematous skin lesions. Subcutaneous immunotherapy (SCIT) refers to repeated contact with gradually increasing doses of allergen extracts, which improve patient tolerance to such allergens and controls, or reduces allergic symptoms. This study aimed to explore the long-term efficacy and safety of SCIT for patients with AD sensitized to house-dust mite (HDM). 

We conducted a retrospective analysis of 378 patients with HDM-sensitized AD. Among these patients, 164 received SCIT plus pharmacotherapy for 3 years (SCIT group) and the other 214 patients received only pharmacotherapy (non-SCIT group). The scoring atopic dermatitis (SCORAD) and pruritus visual analog scale (VAS) scores, laboratory test results, and adverse effects were recorded.

The SCORAD and pruritus VAS scores significantly decreased in the SCIT group. Also, the SCIT group showed higher reduction ratios of SCORAD and pruritus VAS scores than those observed in the non-SCIT group at 3 years after treatment initiation. The risk of development of new sensitization was higher in the non-SCIT group than in the SCIT group (relative risk 1.92 [95% confidence interval {CI}, 1.30-2.85]; p < 0.05). The eosinophil count of the participants significantly differed in the complete response (CR) group (p < 0.05) but not in the non-CR group (p = 0.098). However, the serum total immunoglobulin E value was not significantly reduced (p = 0.204). Of 8421 injections given to the patients, 231 injections (2.74%) showed adverse effects during the treatment period.

Three years of SCIT can significantly reduce the severity and pruritus of moderate-to-severe AD with HDM sensitization. Patients who are multisensitized can also benefit from HDM SCIT. Patients can achieve long-term effects, such as prevention of neoallergen sensitization and inhibition of the allergy march.

Subcutaneous allergen immunotherapy (SCIT) is highly effective but risks exist.

Identify practices that influence systemic allergic reactions (SRs) to SCIT, and SCIT-associated infections.

ACAAI/AAAAI members completed an annual survey of SCIT-related SRs of varying severity (2008-2018). Injection-related infections were queried (2014-2018). Strategies to enforce post-injection waiting times, and to reduce risks from asthma/severe asthma were queried (2016-2018).

Data were gathered on 64.5 million injection visits. Ten confirmed fatalities occurred since 2008, including 3 new fatalities since 2017. One fatal reaction occurred per 7.2 million injection visits (2008-2018). No infections occurred. Practices that tracked the time after injections, and required checking out with office personnel, had significantly lower total (p<0.0001), Grade 3 (severe) (p<0.0008) and Grade 4 (very severe) SRs (p<0.0001). Having more asthmatics on SCIT was associated with more Grade 3 SRs (p<0.02). Not prescribing SCIT in uncontrolled asthmatics was associated with fewer Grade 3 SRs (p=0.02). Having more severe asthmatics on SCIT was associated with more total, Grade 1, and Grade 2 SRs (p<0.0001); 50% of Grade 3 and 4 SRs occurred in severe asthmatics.

SCIT- related fatalities have declined since 2008, with a slight increase in recent years. SCIT is not associated with an increased risk of infections. Tracking the time after injections and checking out with office staff confers significantly lower risks of severe SRs. Asthma, and especially severe asthma, are major risk factors for severe and fatal SRs. Strategies that reduce risks for asthmatics, such as not prescribing SCIT to uncontrolled asthmatics, may lower risks.

Evidence has accumulated that birch pollen immunotherapy reduces rhinoconjunctivitis to pollen of birch-homologous trees. Therapeutic efficacy has been associated with IgE-blocking IgG antibodies. We have recently shown that sera collected after sixteen weeks of sublingual immunotherapy with recombinant Bet v 1 (rBet v 1-SLIT)display strongIgE-blocking bioactivity for Bet v 1. Here, we assessedwhetherrBet v 1-SLIT-induced IgG antibodiesdisplay cross-blocking activity to related allergensin Fagalespollen.

IgE, IgG1 and IgG4 reactivity to recombinantBet v 1, Aln g 1, Car b 1, Ost c 1, Cor a 1, Fag s 1, Cas s 1, and Que a 1 were assessed in pre- and post-SLIT samplesof 17 individuals by ELISA. A basophil inhibition assay using stripped basophils re-sensitized with a serum pool containing high Bet v 1-specific IgElevels was established and used to assess CD63 expression in response toallergens after incubation with pre-SLIT or post-SLIT samples.IgG1 and IgG4 wasdepleted from post-SLIT samples to assess its contribution toIgE-cross-blocking.

rBet v 1-SLIT boostedcross-reactive IgE antibodies and induced IgG1 and IgG4 antibodieswith inter- and intra-individuallydiffering reactivity tothe homologs. Highly variablecross-blocking activitiesof post-SLIT samples to the different allergens werefound. IgG1 and IgG4 antibodies displayed cross-blocking activity with individual variance.

Our mechanistic approach suggested that immunotherapy with the reference allergen Bet v 1 induces individual repertoires of cross-reactive IgG1 and IgG4 antibodies. The cross-blocking bioactivity of these antibodies was also highly variable and neither predictable from protein homology nor IgE-cross-reactivity.

To assess total and allergic rhinitis (AR)-related helthcare cost among AR patients residing in the United States with a focus on patients persisting wiht AIT.

AR patients were identified in the IBM MarketScan database between 1 January 2014 to 31 March 2017. Patients receiving allergy immunotherapy (AIT) were identified with relevant billing codes (earliest AIT claim = index date); non-AIT patients were identified with claims containing a diagnosis code for AR (earliest AR claim = index date). AIT patients reaching 25+ injection claims were analyzed as a separate maintenance cohort. All patients were required to have continuous enrollment for 12 months preceding and following index.

A total of 2,334,530 AR patients were included; 103,207 had at least 1 AIT claim, with 45,279 (43.9%) of these patients reaching maintenance, and 24,640 AIT patients (23.9%) never presenting a single injection claim. Compared to non-AIT patients, patients initiating AIT presented higher rates of baseline comorbidities, including asthma (30.1% vs. 7.5%) and conjunctivitis (21.7% vs. 4.4%). During the follow-up period, patients reaching the maintenance phase of AIT incurred lower total costs than the overall AIT cohort ($10,431±$16,606 vs. $11,612±$24,797), and also presented lower follow-up hospitalization costs ($698±$7,248 vs. $1,281±$12,991) and total medical costs ($7950±$13,844 vs. $8989±$22,019).

Continued efforts are needed to increase patient awareness of available options and adherence to AIT, along with reducing wastage. Despite AIT patients presenting fairly progressed disease at the time of treatment initiation, this therapy remains an economical treatment option, as it was not accompanied by substantial increases in overall healthcare expenditure, and may promote positive societal impacts beyond the direct medical costs.What is known on this topicThe prevalence of allergic diseases has increased over the past 50 years and affects between 10-30% of the world population.Allergic rhinitis (AR) poses a significant economic burden in the form of both direct and indirect costsAllergy immunotherapy (AIT) is the only treatment option able to modify the underlying course of the disease.What this study addsSpecific all-cause and AR-related healthcare costs decreased following the initiation of AIT among patients diagnosed with AR, with the largest decreases observed among AIT patients reaching the maintenance phase of treatment, while non-AIT patients showed increases in all categories assessed over a similar follow-up period.Cost decreases among AIT patients were observed despite increased levels of comorbidities compared to non-AIT patients, as the AIT cohort presented elevated rates of atopic dermatitis (7.1% vs. 2.7%), conjunctivitis (21.7% vs. 4.4%), asthma (30.1% vs. 7.5%), and chronic sinusitis (22.6% vs. 4.9%).An analysis of patients' index subcutaneous AIT consultation revealed substantial variability in the initial treatment costs, with nearly 20% of paid amounts exceeding $1,000; given nearly 1 in 4 AIT patients who get AIT mixed never came back for their first injection, this highlights an opportunity to target frontloaded billing practices and the timing of mixing/injection as an area to minimize healthcare waste.