Tablet allergen immunotherapy: the anaphylaxis issue.

For the first time 15 years ago, tablet allergen immunotherapy (T-AIT) formulations were approved by regulatory agencies for treating allergic rhinitis caused by grass pollen in adults and children aged >5 years. Extensive evidences existed about effectiveness and safety of AIT. However, the safety profile is particularly compelling in children. Generally, T-AIT causes local reactions, mostly in the oral cavity, that are usually mild-to-moderate and often self-resolving. However, systemic allergic reactions are also observed with T-AIT, anaphylaxis representing the most fearsome adverse event, considering that it occurs in subjects treated for allergic rhinitis. Therefore, we conducted a literature search of patients reporting anaphylaxis because of T-AIT. Nine cases of anaphylactic reactions were reported in literature. Notably, no death was reported using T-AIT. This outcome was very important as it underscored the substantial safety of T-AIT. However, T-AIT deserves careful attention, mainly in the pediatric population. In this regard, after the first report of anaphylactic reaction at the first administration of T-AIT, manufacturers recommended that the first dose should be administered in a medical facility in the presence of staff with experience in managing anaphylaxis and the patient should be observed for at least 30 min. Interestingly, reported anaphylactic reactions were due to grass pollen extracts, with no report concerning other allergen extracts. However, it is relevant to note that anaphylactic reactions because of T-AIT are not reported in recent years.

[Component-resolved diagnosis of tree pollen allergen: identify key allergens to develop treatment plans].

With the increasing global prevalence of tree pollen allergies, there has been a significant impact on the quality of life for populations. In North and Central China, birch pollen, cypress pollen, and plane tree pollen are the most common allergens for springtime pollen allergy sufferers. The distribution of plants and patterns of pollen transmission in different geographical areas result in varying pollen exposure outcomes, further complicating the challenges in diagnosis and individualized treatment. This article delves into the research progress and clinical application of tree pollen allergies based on the "Molecular Allergology User's Guide 2.0 (MAUG 2.0) " published by the European Academy of Allergy and Clinical Immunology (EAACI). It discusses major allergen families and component proteins of tree pollen such as PR-10 proteins, profilins, polcalcins, as well as cross-reactive components that may cause pollen-food allergy syndrome. Allergen component diagnostics can distinguish true allergy sufferers from those with multiple allergen reactions, enabling more targeted selection of allergens for specific immunotherapy, thus enhancing treatment effectiveness. Bet v 1 and Cup a 1, for instance, are specific indicators for immunotherapy in birch and cypress allergy patients. Overall, this article provides cutting-edge information for professionals in the field of tree pollen allergies, offering in-depth exploration of tree pollen allergen component proteins, clinical manifestations, and treatment-related research, aiding in better understanding and addressing the challenges of tree pollen allergies.

Effectiveness of sublingual immunotherapy in pediatric cedar pollinosis: A real-world database study.

BACKGROUND: Pediatric allergic rhinitis (AR), including cedar pollinosis (CP), is increasing in Japan. We investigated the effects of sublingual immunotherapy (SLIT), which has limited studies of its effectiveness in real-world settings, on children with CP. METHODS: This retrospective cohort study used a claim database in 2018-2021. Children aged ≤15 years with CP records in 2019 were eligible and were followed up through 2021. We included 2962 CP children undergoing SLIT and 547 who were not. The medication score was used to evaluate SLIT effectiveness in the cedar pollen dispersal season each year. Adverse events and the occurrence of allergic diseases were also evaluated. RESULTS: Medication score was higher in the SLIT group during the index period but lower in 2021 compared to the non-SLIT group (mean ± standard deviation: 5.17 ± 2.39 and 4.74 ± 2.38 in 2019, 3.13 ± 2.30 and 3.55 ± 2.48 in 2021, respectively). The adjusted mean difference between groups from 2019 to 2021 was -0.62 (95% confidence interval: -0.86 to -0.39, p < .0001), and the medication score was reduced in the SLIT group (risk ratio: 1.2: 1.1 to 1.3). The occurrence of adverse events involving abdominal disorders (adjusted odds ratio [aOR]: 0.64: 0.51 to 0.81), asthma exacerbation (aOR: 0.37: 0.24 to 0.57), and allergic diseases involving hay fever unrelated to CP (aOR: 0.60: 0.45 to 0.80) or asthma (aOR: 0.71: 0.58 to 0.86) was lower in the SLIT group. CONCLUSION: In children with CP, SLIT is effective, well tolerated, and could decrease the occurrence of other allergic diseases.

Decreased Basophil Activation against House Dust Mite after Japanese Cedar Pollen Subcutaneous Immunotherapy: A Retrospective Study.

BACKGROUND: Allergen-specific immunotherapy (AIT), an established treatment for allergic diseases, prevents the development of other allergic manifestations. Although the mechanisms remain unclear, AIT has been shown to reduce basophil activation (BA) against nontarget allergens. OBJECTIVES: The aim of this study was to assess immunological changes in Dermatophagoides farinae (Der f) after Japanese cedar pollen (JCP)-based subcutaneous immunotherapy (SCIT) monotherapy. METHOD: The data of 16 patients (age: 6-37 years) with JCP-induced allergic rhinitis who were sensitive to Der f (serum Der f-specific immunoglobulin E [IgE] level >0.34 kUA/L) and received JCP-based SCIT for 5 years were reviewed retrospectively. BA by Der f and JCP extracts and serum-specific IgE and immunoglobulin G4 (IgG4) levels against these allergens were evaluated before and after completing 5 years of JCP-based SCIT monotherapy. RESULTS: The areas under the dose-response curves of BA by Der f and JCP extracts were significantly reduced (p = 0.02 and p = 0.002, respectively). JCP-specific IgE levels decreased and JCP-specific IgG4 levels increased significantly (p < 0.001 for both), whereas Der f-specific IgE and IgG4 levels did not change significantly. CONCLUSIONS: JCP-based SCIT monotherapy reduced Der f-specific BA. These findings suggest that JCP-based SCIT has the potential to modulate immune response toward nontarget allergens.

Prevention Is Better than Cure: Impact of Allergen Immunotherapy on the Progression of Airway Disease.

Allergen immunotherapy is highly effective for seasonal pollinosis. Three years of treatment results in long-term efficacy. This disease modification is accompanied by downregulation of allergen-specific Th2 responses and the induction of persistent specific IgG- and IgA-associated IgE-blocking activity. In children with seasonal rhinitis, both subcutaneous and sublingual pollen immunotherapy have been shown to reduce the development of asthma symptoms and asthma medication requirements. House dust mite tablet allergen immunotherapy has been shown to be effective for perennial mite-driven rhinitis in adults and children and may suppress asthma exacerbations, whereas its long-term efficacy has yet to be explored. The success of primary prevention of peanut allergy in childhood by introduction of peanut into the diet during infancy provides a strong rationale to explore whether primary prevention of inhalant allergies and asthma may also be possible. House dust mite allergy is a major risk factor for developing asthma. Preliminary data in at-risk children suggest that sublingual house dust mite immunotherapy initiated during infancy could reduce the onset of multiple allergen sensitizations and prevent the development of asthma at age 6 years. This possibility should now be explored in an adequately powered, prospectively randomized controlled trial.

Sublingual immunotherapy for cedar pollinosis possibly triggers eosinophilic esophagitis.

Sublingual immunotherapy (SLIT) is an effective and popular treatment for cedar pollinosis. Although SLIT can cause allergic side effects, eosinophilic esophagitis (EoE) is a lesser-known side effect of SLIT. A 26-year-old male with cedar pollinosis, wheat-dependent exercise-induced anaphylaxis, and food allergies to bananas and avocados presented with persistent throat itching, difficulty swallowing, heartburn, and anterior chest pain 8 days after starting SLIT for cedar pollinosis. Laboratory examination showed remarkably elevated eosinophils, and esophagogastroduodenoscopy revealed linear furrows in the entire esophagus. Histological examination of an esophageal biopsy specimen revealed high eosinophil levels. The patient was strongly suspected with EoE triggered by SLIT. The patient was advised to switch from the swallow to the spit method for SLIT, and the symptoms associated with SLIT-triggered EoE were reduced after switching to the spit method. This case highlights the importance of recognizing SLIT-triggered EoE as a potential side effect of SLIT for cedar pollinosis, especially with the increasing use of SLIT in clinical practice. EoE can occur within a month after initiating SLIT in patients with multiple allergic conditions, as observed in our case. Furthermore, the spit method should be recommended for patients who experience SLIT-triggered EoE before discontinuing SLIT.

Local nasal immunotherapy with birch pollen-galactomannan conjugate-containing ointment in mice and humans.

BACKGROUND: Allergen immunotherapy (AIT) is the only disease-modifying treatment for immunoglobulin (Ig) E-mediated allergy. Owing to the high prevalence and early onset of hay fever and pollen-food allergy syndrome (PFAS), a safer and simpler treatment method than conventional AIT is needed. To develop a local nasal immunotherapy using an ointment containing hypoallergenic pollen and assess its efficacy in mice and healthy humans. METHODS: Hypoallergenicity was achieved by combining pollen and galactomannan through the Maillard reaction to create birch pollen-galactomannan conjugate (BP-GMC). The binding of galactomannan to Bet v 1 was confirmed using electrophoresis and Western blotting (WB). Binding of specific IgE antibodies to BP-GMC was verified using enzyme-linked immunosorbent assay (ELISA) and basophil activation test (BAT). The localization of BP-GMC absorption was confirmed using a BALB/c mouse model. BP-GMC mixed with white petrolatum was intranasally administered to 10 healthy individuals (active drugs, 8; placebo, 2) for 14 days. RESULTS: In electrophoresis and WB, no 17-kDa band was observed. In ELISA and BAT, BP-GMC did not react to specific IgE but was bound to IgA and IgG. In the mouse model, BP-GMC was detected in nasopharyngeal-associated lymphoid tissues. In the active drug group, the salivary-specific IgA level significantly increased on day 15 (p = 0.0299), while the serum-specific IgG level significantly increased on day 85 (p = 0.0006). CONCLUSIONS: The BP-GMC ointment rapidly produced antagonistic antibodies against IgE; it is safe and easy to use and might serve as a therapeutic antigen for hay fever and PFAS.

Tolerability of sublingual versus vestibular allergy immunotherapy tablet administration: A randomized pilot study.

BACKGROUND: Local application site reactions are common with sublingual allergy immunotherapy (AIT)-tablets for the treatment of allergic rhinitis/conjunctivitis (AR/C) and occasionally lead to treatment discontinuation. Because of the lower mast cell density in the vestibular mucosa than the sublingual area, vestibular AIT-tablet administration may result in fewer adverse events (AEs). This pilot study evaluated the tolerability of the vestibular administration route of AIT-tablets compared with the sublingual route in adult subjects with AR/C. METHODS: Adults (n = 164) aged 18-65 years with AR/C treated with daily birch pollen, grass pollen, ragweed pollen or house dust mite AIT in tablet form were randomized 1:1 to vestibular or sublingual administration for 28 days, followed by 28 days of sublingual administration only. The primary endpoint was the severity (mild, moderate, severe) of local treatment-related adverse events (TRAEs) during the first 28 days of treatment. RESULTS: During the first 28 days, the percentage of subjects in the vestibular and sublingual groups reporting mild TRAEs were 55.6% versus 50.6%, respectively; moderate TRAEs were 27.2% versus 30.1%; and severe TRAEs were 12.3% versus 6.0% (p = .16). In the vestibular group, 95.1% of the subjects experienced at least one TRAE during the first period versus 81.9% in the sublingual group (p = .01) and discontinuation rates due to AEs were higher (12.3% vs. 3.6%). CONCLUSION: The frequencies of subjects experiencing severe TRAEs, at least one TRAE, and discontinuations due to AEs at the initiation of AIT-tablets were numerically higher with vestibular administration than sublingual administration. Sublingual administration should remain the standard of care for subjects treated with AIT-tablets for AR/C.

A randomized, double-blind, placebo-controlled trial with mannan-conjugated birch pollen allergoids.

BACKGROUND: There is still great need to develop new strategies to improve the efficacy of allergen immunotherapies with optimal safety standards for patients. A new promising approach is to couple allergoids to mannan. The objective of this phase IIa/IIb study was to identify the optimal dose of mannan-conjugated birch pollen allergoids for the short-course treatment of birch pollen-induced allergic rhinoconjunctivitis. METHODS: For this prospective, randomized, double-blind, placebo-controlled, dose-finding study, 246 birch pollen-allergic adults received 0.5 mL placebo or 1000, 3000 or 10,000 mTU/mL of mannan-conjugated birch pollen allergoids at five pre-seasonal visits. Efficacy was assessed by comparing allergic rhinoconjunctivitis symptoms and use of anti-allergic medication during the peak of the birch pollen season 2020. Immunologic, tolerability and safety effects were also analysed. RESULTS: The highest dose of mannan-conjugated birch pollen allergoids reduced the combined symptom and medication score during the peak birch pollen season by a median of 24.7% compared to placebo. The production of Bet v 1 specific IgG4 significantly increased in a dose-dependent manner (3.6- and 4.5-fold) in the 3000 and 10,000 mTU/mL groups. The Bet v 1 specific IgE/IgG4 ratio was also strongly reduced (up to -70%). No fatalities nor serious adverse events were reported, and no adrenaline was used. In total, four systemic reactions occurred (two grade I and two grade II). CONCLUSION: All doses of mannan-conjugated birch pollen allergoids can be considered as safe. Since the application of 10,000 mTU/mL resulted in the highest efficacy, this dose qualifies for further investigation.

Efficacy of a Non-Pharmacological Intervention in Seasonal Allergic Rhinitis Symptoms.

BACKGROUND: Patients suffering from allergic rhinitis seek for several therapeutic symptomatic options, including nonconventional treatments, to control their symptoms. OBJECTIVES: Through the present proof-of-concept study, we prospectively investigated the potential role of Puressentiel® nasal protection spray (SNPA) in patients suffering from cypress pollen allergic rhinitis. METHODS: In 15 adults, we performed two nasal provocation tests, with a cypress pollen extract, with a 15-day interval, with and without previous randomized administration of SNPA, and evaluated a nasal symptom score, the nasal inspiratory peak flow, and the concentration of inflammatory cytokines in the nasal lavage after the procedures. RESULTS: Comparing results in patients challenged with and without the SNPA spray before the nasal challenge, we found a 57% mean decrease in symptoms, and a 62% average difference in inspiratory peak flow, after the use of the spray. CONCLUSIONS: Puressentiel® SNPA is effective in reducing nasal symptoms, as assessed by nasal symptoms score and nasal inspiratory peak flow, and could be a valid natural non-pharmacological option in patients suffering from allergic rhinitis.

[CLINICAL EFFICACY OF SUBLINGUAL IMMUNOTHERAPY WITH CEDAR POLLEN IN A YEAR OF MASSIVE CEDAR POLLEN DISPERSAL AND ITS EFFECT ON JAPANESE CYPRESS POLLINOSIS].

BACKGROUND: We investigated the effect of sublingual immunotherapy (SLIT) on Japanese cedar and cypress pollinosis in a mass scattering year of cedar pollen (total counts: 12353 grains/cm2, approximately four times the average). METHODS: SLIT patients of 84 in the first year, 107 in the second year and 67 in the third year treated with Cedarcure® were included. During the 2023 cedar and cypress pollen dispersal season, nasal and eye symptoms and general symptoms were examined using a visual analog scale (VAS). RESULTS: The VAS during the cedar season significantly decreased to improve with the number of years of SLIT, but the VAS during the cypress period slightly increased. A questionnaire survey before SLIT revealed that only 0.9% to 3.6% of patients had strong cypress symptoms. However, sneezing (p＜0.01), rhinorrhea, itchy eyes and total symptoms (p＜0.05) in the third year of SLIT were significantly stronger during the cypress period than during the cedar period. The VAS of total symptoms during the Japanese cedar pollen season were not affected by the pollen count, and the cure rate was affected by SLIT in the third year. CONCLUSION: The clinical efficacy of cedar SLIT on cedar pollinosis was high even in a mass scattering year, and the effect increased with the number of years of treatment. On the other hand, it was shown that the clinical efficacy on cypress pollinosis was insufficient.

Conception and pilot testing of a self-management health application for patients with pollen-related allergic rhinitis and allergic asthma-the APOLLO app.

It has been shown that pollen information services are an important self-management tool for patients with pollen-related allergic rhinitis (AR) and allergic asthma (AA). This study aimed to design an online application for patients with AR and AA, which supports patients to better manage their disease as well as to evaluate the app and present the first results of the pilot study. The pollen data were obtained from the electronic pollen information network of Bavaria, Germany. Participants were asked to fill in their allergy-related complaints in the app over a 60-day period. Subsequently, the app was evaluated. Indices and diagrams visualized the participants' individual complaints as well as the daily pollen concentration in the air. In order to motivate participants to complete the app on a daily basis, we used elements of gamification. Two thirds of the participants (N = 46) reported feeling better informed about pollen counts and their allergy when using the app. The app's simple and comprehensible design was rated positively. More than 80% of the participants would recommend the app to their family and friends. The app can be a tool for patients with AR and AA to better understand their disease.

[A MULTICENTER CLINICAL SURVEY ABOUT THE PREVALENCE OF JAPANESE CYPRESS POLLINOSIS AND THE EFFICACY OF SUBLINGUAL IMMUNOTHERAPY WITH JAPANESE CEDAR POLLEN EXTRACT DURING JAPANESE CYPRESS POLLEN DISPERSAL PERIOD].

BACKGROUND: Little is known whether sublingual immunotherapy using Japanese cedar pollen extract (cedar SLIT) is effective for not only Japanese cedar pollinosis but also Japanese cypress pollinosis. We investigated the prevalence rate of Japanese cypress pollinosis, efficacy of cedar SLIT on cypress pollinosis and patients' wish to receive cypress SLIT. METHODS: We investigated a multi-center (31 institutions), cross-sectional survey using a self-administrated questionnaire with four questions for patients received cedar SLIT aged from 5 to 69 years old. RESULTS: 2523 subjects were enrolled for analysis. 83.4% of them had pollinosis symptoms during cypress season before cedar SLIT. In such patients, 37.4% experienced lessened efficacy of cedar SLIT during cypress season. Both the prevalence of cypress pollinosis and the lessened efficacy of cedar SLIT on cypress pollinosis were significantly seen in western Japan as compared to eastern Japan. 76.1% of the subject having cypress pollinosis before SLIT wished to receive cypress SLIT if it is available. CONCLUSION: A lessened efficacy of cedar SLIT during cypress season was broadly seen in Japan, and further showed a regional difference. Together with the finding of high wish by patients, these results suggest a development of cypress SLIT is desirable.

[Research progress on pollen food allergy syndrome].

Pollen food allergy syndrome (PFAS) is an IgE-mediated allergic reaction that occurs when some pollinosis patients ingest certain plant-derived food that contains cross-reactive allergenic components. PFAS is prevalent in both children and adult pollinosis patients. In most cases, PFAS symptoms are confined to the oropharynx and occur within several minutes after oral contact with food. Therefore, PFAS has been also referred as oral allergy syndrome (OAS). A small proportion of PFAS patients would experience systemic symptoms or anaphylaxis. Currently, the diagnosis of PFAS is mainly based on clinical history and allergic tests [skin prick tests and(or) serum specific IgE tests]. Oral provocation tests are used to verify atypical patients. Component-resolved diagnosis is essential for further precise diagnosis and treatment. Management options for PFAS include lifestyle adjustment, symptomatic medication, and immunotherapy. The efficacy and appropriate population for immunotherapy need further investigation. This article aims to update the knowledge on epidemiology, pathogenesis and clinical management of PFAS, thereby enhancing clinicians' understanding as well as treatment progress of this disease entity.

Efficacy and safety of Artemisia annua sublingual immunotherapy in patients with seasonal allergic rhinoconjunctivitis over two pollen seasons.

OBJECTIVE: This study investigates the efficacy and safety of sublingual immunotherapy (SLIT) with A. annua allergens in patients with seasonal allergic rhinoconjunctivitis over two pollen seasons. METHODS: Seventy patients with moderate-severe seasonal allergic rhinoconjunctivitis were divided evenly into the SLIT and control groups. The SLIT last from 3 months before the summer-autumn pollen season in 2021 till the end of the summer-autumn pollen season in 2022. The daily individual symptom score, total rhinoconjunctivitis symptom score (dTRSS), total medication score (dTMS), combined score of medication and rhinoconjunctivitis symptom (dCSMRS), visual analog scale (VAS) score, and adverse events (AEs) were evaluated. RESULTS: The average pollen concentration in 2022 was twice that previous two-year during the pollen season. Fifty-six patients completed treatments (SLIT group: 29, control group: 27). Compared with baseline, the individual symptoms, dTRSS, dTMS, dCSMRS, and VAS scores of SLIT group declined in 2021. After 16 months of SLIT, all efficacy indexes in 2022 were still lower than baseline and equivalent to those in 2021. In control group, the efficacy indexes in 2022 were higher than that in 2020 and 2021. The efficacy indexes of SLIT group were lower than those of control group in 2021 and 2022. SLIT is effective for both mono- and poly-sensitized patients. AEs incidence in SLIT group was 82.7% without severe AEs. CONCLUSIONS: The A. annua-SLIT can obtain efficacy and safety over two pollen seasons for patients with moderate-severe seasonal allergic rhinoconjunctivitis.

Clinical efficacy and safety of coseasonal initiation of Artemisia annua sublingual immunotherapy on patients with Artemisia-induced rhinoconjunctivitis.

PURPOSE: Patients with seasonal allergic rhinoconjunctivitis (SARC) might seek evaluation and treatment when symptoms appear during the pollen season. It is unclear whether coseasonal-initiated sublingual immunotherapy (SLIT) would be effective and safe for SARC. This study aims to identify the feasibility of initiating Artemisia annua SLIT during the pollen season. MATERIALS AND METHODS: Sixty patients with Artemisia-induced SARC were equally recruited into the SLIT and control groups during the pollen season in 2021. The SLIT group was treated with standardized Artemisia annua SLIT drops using a modified dosing schedule combined with pharmacotherapy, while the control group only received pharmacotherapy. Diary cards for clinical symptoms, rescue medication use, and adverse events (AEs) were recorded during the pollen seasons. Objective measures, including average daily combined scores of medication and rhinoconjunctivitis symptoms (CSMRS), total rhinoconjunctivitis symptom score (TRSS), total medication score (TMS), and the score of visual analog scale (VAS) were calculated to evaluate the efficacy of SLIT. Safety was assessed through the occurrence and severity of AEs. RESULTS: In total, 80.0 % (24/30) patients in the SLIT group and 86.67 % (26/30) patients in the control group completed the study. The severity of SARC, which was assessed by objective measures including CSMRS, TRSS, TMS, and VAS of the SLIT group and the control group, was generally at the same level during the 2021 pollen season, except for the medical consumption, which the score of TMS was slightly higher in the SLIT group. After one year of treatment, the scores of CSMRS, TRSS, and VAS in the SLIT group were significantly improved compared with the control group (all P < 0.001), and the difference in the TMS between the two groups disappeared (P > 0.05). Moreover, clinical improvement of the four objective measures was also observed in the SLIT group compared with the baseline value (P < 0.001). Overall, 9/24 patients in the SLIT group experienced mild local AEs, and two patients experienced mild systemic AEs during the SLIT period. CONCLUSIONS: This controlled preliminary study identified that coseasonal-initiated Artemisia annua SLIT treatment for one year was generally safe and effective in improving the symptoms of SARC patients induced by Artemisia annua pollen.

Intralymphatic immunotherapy with birch and grass pollen extracts. A randomized double-blind placebo-controlled clinical trial.

INTRODUCTION: There is a need to evaluate the safety and efficacy of intralymphatic immunotherapy (ILIT) for inducing tolerance in patients with allergic rhinitis. METHODS: Thirty-seven patients with seasonal allergic symptoms to birch and grass pollen and skin prick test >3 mm and/or IgE to birch and timothy >0.35 kU/L were randomized to either ILIT, with three doses of 0.1 mL of birch pollen and 5-grass pollen allergen extracts on aluminium hydroxide (10,000 SQ-U/ml; ALK-Abelló) or placebo using ultrasound-guided intralymphatic injections at monthly intervals. Daily combined symptom medical score and rhinoconjunctivitis total symptom score were recorded during the peak pollen seasons the year before and after treatment. Rhinoconjunctivitis total symptom score, medication score and rhinoconjunctivitis quality of life questionnaire were recorded annually starting 2 years after treatment. Circulating proportions of T helper cell subsets and allergen-induced cytokine and chemokine production were analysed using flow cytometry and ELISA. RESULTS: There were no differences between the groups related to daily combined symptom medical score the year before and after treatment. Two years after ILIT (after unblinding), the actively treated group reported significantly fewer symptoms, lower medication use and improved quality of life than did the placebo group. After the pollen seasons the year after ILIT, T regulatory cell frequencies and grass-induced IFN-γ levels increased only in the actively treated group. CONCLUSION: In this randomized controlled trial, ILIT with birch and grass pollen extract was safe and accompanied by immunological changes. Further studies are required to confirm or refute the efficacy of the treatment.

Evolution of Immunotherapy Against Pollen Allergy.

Allergic diseases have increased worldwide during the last century and are a major disease burden globally. Several substances can induce allergic sensitization and elicit allergic symptoms in sensitized individuals. Pollen grains are one of the main causes of allergic rhinitis and asthma, and the prevalence of different pollen species depends on the climate, geographical regions, flora, and seasons. In addition to avoiding exposure to pollens, anti-allergic drugs are commonly used to mitigate the symptoms of allergies. However, these drugs need to be administered repeatedly as long as the symptoms prevail, usually life-long. Allergen immunotherapy (AIT) is currently the only disease-modifying approach that can prevent the natural progression of the disease (also known as an allergic march), provide a long-lasting therapeutic effect, and prevent the worsening of the symptoms and the occurrence of new sensitizations in allergic individuals. Since the pioneering clinical studies conducted more than 100 years ago using subcutaneously administered pollen extract to treat hay fever, significant advances have been made in the field of AIT. Starting from this pioneering approach, in this review, we have discussed the evolution of the products used for AIT with particular emphasis on pollen allergoids, the chemically modified pollen extracts characterized by lower allergenicity and comparable immunogenicity, and the different routes of administration used for AIT.