Risk factors for systemic reactions in typical cold urticaria: Results from the COLD-CE study

BACKGROUND

Cold urticaria (ColdU), that is, the occurrence of wheals or angioedema in response to cold exposure, is classified into typical and atypical forms. The diagnosis of typical ColdU relies on whealing in response to local cold stimulation testing (CST). It can also manifest with cold-induced anaphylaxis (ColdA). We aimed to determine risk factors for ColdA in typical ColdU.

METHODS

An international, cross-sectional study COLD-CE was carried out at 32 urticaria centers of reference and excellence (UCAREs). Detailed history was taken and CST with an ice cube and/or TempTest^® performed. ColdA was defined as an acute cold-induced involvement of the skin and/or visible mucosal tissue and at least one of: cardiovascular manifestations, difficulty breathing, or gastrointestinal symptoms.

RESULTS

Of 551 ColdU patients, 75% (n = 412) had a positive CST and ColdA occurred in 37% (n = 151) of the latter. Cold-induced generalized wheals, angioedema, acral swelling, oropharyngeal/laryngeal symptoms, and itch of earlobes were identified as signs/symptoms of severe disease. ColdA was most commonly provoked by complete cold water immersion and ColdA caused by cold air was more common in countries with a warmer climate. Ten percent (n = 40) of typical ColdU patients had a concomitant chronic spontaneous urticaria (CSU). They had a lower frequency of ColdA than those without CSU (4% vs. 39%, p = .003). We identified the following risk factors for cardiovascular manifestations: previous systemic reaction to a Hymenoptera sting, angioedema, oropharyngeal/laryngeal symptoms, and itchy earlobes.

CONCLUSION

ColdA is common in typical ColdU. High-risk patients require education about their condition and how to use an adrenaline autoinjector.

Systemic Reactions to Dust Mite Subcutaneous Immunotherapy: A 3-Year Follow-up Study

Purpose

The incidence of allergen specific immunotherapy-related systemic reactions (SRs) varies among different studies, and many factors are likely to contribute to SRs. This study aims to investigate the incidence, characteristics, and risk factors of SRs to standardize dust mite-specific subcutaneous immunotherapy (SCIT) in Central China.

Methods

All patients receiving standardized dust mites (100-100,000 SQ-U/mL; Alutard SQ, Hørsholn, Denmark) immunotherapy were followed up. Recorded data included demographics, diagnosis, patient status, pulmonary function testing results before and after each injection, allergen dosage, and details of SRs.

Results

From June 2011 to August 2014, a total of 208 patients received 4,369 injections; 27 (13.0%) patients experienced 48 (1.1%) systemic reactions. Most of the SRs were grade 2 reactions (n=30, 62.5%), followed by grade 1 (n=11, 22.9%), grade 3 (n=7, 14.6%), and no fatal reactions occurred. Forty-six SRs (95.8%) occurred within 30 minutes. Higher SR rates were associated with high concentration extracts (100,000 SQ-U/mL), injections with concomitant local reactions (LRs), children, asthma and high sensitivity (skin prick test 3+/4+ and/or sIgE≥17.5 kUA/L) (P<0.05). The estimated odds of SRs increased in children (OR=6.57; 95% CI: 1.88-22.97, P=0.003), asthmatic patients (OR=4.10; 95% CI: 1.72-9.80, P=0.002), and injections with LRs (OR=2.41; 95% CI: 1.33-4.36, P=0.004).

Conclusions

The incidence of SRs to dust mite SCIT was low, and multiple factors were associated with the increased incidence of SRs. Children, asthmatics and patients with concomitant LR may be prone to develop SRs.

Incidence and risk factors for subcutaneous immunotherapy anaphylaxis: the optimization of safety

Fatal reactions related to subcutaneous allergen immunotherapy are rare: one event in 2.5 million injections has been reported in the USA and none in Europe. The prevalence of very severe systemic reactions (systemic adverse events [SAEs]) is one in 1 million injections. Though the serious events rate is decreasing and the majority of SAEs (∼0.2% per injection) are moderate and reversible, they still represent a major concern. Uncontrolled asthma, long-term therapy with β-blockers and high degree of allergen sensitivity are generally considered risk factors. The relevance of other conditions, like previous local reactions, the use of extracts conjugated with adjuvants and accelerated build-up schedules is controversial, as well as the role of preventative strategies. A careful risk assessment of patients and optimal administration procedures may significantly decrease the risk of SAEs. However, more uniform safety data are required and an accurate safety profile should be provided for every allergen product.

The rate of epinephrine administration associated with allergy skin testing in a suburban allergy practice from 1997 to 2010

Allergy skin testing is considered a safe method for testing for IgE-mediated allergic responses although anaphylactic events can occur. Reported rates of anaphylaxis per patient are not consistent and range from 0.008 to 4%. The aim of this study was to determine the rate of epinephrine use associated with allergy skin-prick testing (SPT) and intradermal testing (IDT) in a suburban practice over 13 years. This retrospective chart review used billing and procedure coding records during the time period from January 1997 to June 2010 to identify encounters where epinephrine was administered after SPT or IDT. Patient encounters with procedure codes for skin testing plus either parenteral epinephrine, corticosteroid, antihistamine, or i.v. fluid administration were identified. These patient charts were reviewed to determine if epinephrine was administered, whether systemic reactions developed, and rates of epinephrine administration were calculated. There were 28,907 patient encounters for SPT and 18,212 for IDT. Epinephrine was administered in six patient encounters (0.02%) where SPT was performed; no IDT encounters led to epinephrine administration. There were no fatalities. Allergy skin testing to a variety of allergens, when administered by well-trained personnel, is a safe procedure. This study, involving the largest population to date, showed a rate of systemic reactions requiring epinephrine of 20 per 100,000 SPT visits. No epinephrine was given after IDT.

Diagnosis and management of hypersensitivity reactions to vaccines

INTRODUCTION

Many countries in Europe now recommend and enforce mandatory vaccinations to improve vaccination coverage. Thus, the number of adverse events following immunization (AEFI) may show an increase. Among these events, severe hypersensitivity reactions to vaccines are rare. However, it is important that they be identified and recognized so that they may be adequately managed.

AREAS COVERED

The literature search was undertaken through PubMed and Embase to identify English-language papers focusing on hypersensitivity to vaccines.

EXPERT OPINION

Hypersensitivity reactions following vaccinations are rare and are classified according to their chronology and extension: immediate when they occur within the first 4 hours following administration and non-immediate when they occur later. Local reactions are the most common adverse event following injection of vaccines and generally do not require any allergy workup. Immediate reactions, however, are potentially IgE-mediated and require an allergy workup. In general, a previously known food allergy (i.e., egg or milk) is not a contraindication to immunizations. Patients with a known allergy to gelatin, yeast, latex, antibiotics, or other specific components of vaccines require an allergy workup before administration of the vaccine.

Zn-0.8Mg-0.2Sr (wt.%) Absorbable Screws-An In-Vivo Biocompatibility and Degradation Pilot Study on a Rabbit Model

In this pilot study, we investigated the biocompatibility and degradation rate of an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. An alloy screw was implanted into one of the tibiae of New Zealand White rabbits. After 120 days, the animals were euthanized. Evaluation included clinical assessment, microCT, histological examination of implants, analyses of the adjacent bone, and assessment of zinc, magnesium, and strontium in vital organs (liver, kidneys, brain). The bone sections with the implanted screw were examined via scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). This method showed that the implant was covered by a thin layer of phosphate-based solid corrosion products with a thickness ranging between 4 and 5 µm. Only negligible changes of the implant volume and area were observed. The degradation was not connected with gas evolution. The screws were fibrointegrated, partially osseointegrated histologically. We observed no inflammatory reaction or bone resorption. Periosteal apposition and formation of new bone with a regular structure were frequently observed near the implant surface. The histological evaluation of the liver, kidneys, and brain showed no toxic changes. The levels of Zn, Mg, and Sr after 120 days in the liver, kidneys, and brain did not exceed the reference values for these elements. The alloy was safe, biocompatible, and well-tolerated.

Selection of patients for sublingual versus subcutaneous immunotherapy

Allergen immunotherapy is the sole treatment for IgE-mediated allergic diseases directed at the underlying mechanism. The two widely accepted administration routes are sublingual (SLIT) and subcutaneous (SCIT). We reviewed how patients should best be selected for immunotherapy and how the optimal administration route can be defined. Before deciding SCIT or SLIT, appropriate selection of patients for allergen immunotherapy (AIT) is mandatory. To be eligible for AIT, subjects must have a clear medical history of allergic disease, with exacerbation of symptoms on exposure to one or more allergens and a corresponding positive skin or in vitro test. Then the route of administration should be based on: published evidence of clinical and immunologic efficacy (which varies per allergic disease and per allergen); mono- or multi-allergen immunotherapy, for SLIT multi-allergen immunotherapy was not effective; safety: adverse events with SLIT are more frequent, but less severe; and, costs and patient preferences, closely related to adherence issues. All these are discussed in the article.

Large local reaction to Hymenoptera stings: Sound studies are needed to change a shared concept

The natural history of large local reactions to Hymenoptera stings allowed to estimate the risk to develop a systemic reaction after an initial large local reaction in about 4% of patients. A recently published study claimed that such risk concerns instead around one-fourth of patients. However, such study is flawed by serious imprecision, particularly the unreliable identification by patients of the culprit insect, as well as the dubious identification of the causative venom in multisensitized patients. Also, the authors criticized previous studied because of the limited number of patients, while they included in the study 662 patients. Indeed, when only patients clearly restung by the same insect according to their history data were considered, the number of patients fell to 35. These data are unable to change the current shared concept on the low risk of systemic reactions in patients with initial large local reaction.

A 5-year study of systemic reactions using both shared and patient-specific vaccines

The safety of shared specific vaccines (SSVs) has been questioned by some experts. The purpose of this study was to evaluate the safety of SSVs. Details of systemic allergic reactions after subcutaneous immunotherapy injections were captured on a standardized form from July 2005 to July 2010. Patient records were evaluated for factors that might be associated with increased rate of systemic reactions and, in addition, were examined for any errors. Systemic reaction rates (SRRs) using a combination of shared and patient-specific vaccines (PSVs) were similar to previously reported studies (0.23 reactions per 100 shots). There were no systemic reactions resulting from errors where the incorrect shared allergen was administered, but we did note one reaction after an erroneously administered PSV. There were two dosage errors associated with both shared and patient-specific immunotherapy. Most reactions were mild to moderate (World Allergy Organization grade, 1 or 2). Severe reactions with 911 activations were noted in six patients. Thirty percent of reactions occurred out of the office and the average time to reaction was 48 minutes. Epinephrine was administered in only 60% of patients. Epicutaneous reactivity to mites, cats, dogs, and pollen but not mold occurred significantly more in reactors. Differences in SRRs were encountered between satellite offices. Using a combination of SSV and PSV, SRRs were similar to previously reported studies; moreover, no systemic reactions occurred where a SSV was erroneously administered. SRR surveillance is a useful safety tool.

The safety of sublingual immunotherapy, can the rare systemic reactions be prevented?

Introduction: The safety of subcutaneous immunotherapy (SCIT), and particularly the dramatic issue of fatal reactions, has been an obstacle that limited the implementation of a therapy with unique characteristics of action on the causes of allergy. The introduction of sublingual immunotherapy (SLIT) was aimed at solving safety problems while maintaining clinical efficacy.Areas covered: For more than 20 years, SLIT has been based on allergen extracts in drops at low average doses. As evidenced by meta-analyses, the typical adverse events (AE) have consisted of local reactions in the mouth and throat. Unlike the injection route, no correlation was observed between the administered dose and AEs. The development of SLIT products in tablets, based on higher doses than drops, has somewhat changed the concept of SLIT safety. Although large trials, performed to obtain regulatory agency approval, have shown overall high safety, rare anaphylactic reactions have been described.Expert opinion: SLIT is globally safe, and no fatal reactions have ever been reported, but with currently available high biological potency products it is necessary to follow prudential rules, such as the administration of the first dose under medical supervision and the thorough education of patients to avoid taking of higher doses than recommended.

Safety of uSCIT-MPL-4: prevalence and risk factors of systemic reactions in real life

Aim: We assessed the safety of allergoid adjuvanted by monophosphoryl lipid A (uSCIT-MPL-4) in a real-life setting. Materials & methods: Patients treated with uSCIT-MPL-4 were followed-up for 1 year. Systemic reactions (SRs) were registered and the association with potential risk factors was evaluated. Results: 2929 patients were included. Grade 0, 1, 2, 3 and 4 SR reactions were observed respectively in 3.3, 1.5, 0.31, 0.07 and 0.07% of patients. A significant association was detected between Grade ≥1 SRs and: female gender, number of administrations, previous local reactions. Conclusion: uSCIT-MPL-4 is safe. Local reactions should be accurately assessed as they may represent a risk factor for Grade ≥1 SRs, together with gender and number of doses/year.

Comparison of moderate to severe systemic reactions with honeybee and wasp in children

BACKGROUND

The effect of the type of Hymenoptera on the severity of systemic reactions (SRs) is a controversial issue. The aim of the present study was to evaluate demographic, clinical, diagnostic, and therapeutic features of moderate-to-severe SRs in children with venom hypersensitivity and to compare the role of the honeybee and wasp stings in these reactions.

METHODS

Data on children with moderate-to-severe SRs after a Hymenoptera sting were retrospectively collected for a 17-year period.

RESULTS

A total of 55 children with moderate-to-severe SRs (wasp: 44, honeybee: 11) to venom stings were included in the study. In the honeybee group, comorbid allergic rhinitis and any type of atopic disease was more frequent compared to the wasp group (p = 0.009 and p = 0.01, respectively). In 50.9% of the children, family history of SR to the same venom type was higher in the honeybee group (p = 0.02). Dyspnea was more frequent in the wasp, and cyanosis was more frequent in the honeybee compared to each other (p = 0.02 and p < 0.001, respectively). Prick tests results were significantly different between the groups (p = 0.038). There was no difference between honeybee and wasp in moderate-to-severe SR groups in terms of seasonal tendency, age at admission, age at first SR, gender, previous history of SR, sting localization, latency, and affected organ systems (p > 0.05 for each).

CONCLUSION

Moderate-to-severe SRs with honeybee and wasp venoms in children may differ in the severity of respiratory symptoms/signs at presentation, in addition to comorbidity of atopic diseases and family history of the SRs.

Hymenoptera Venom Allergy and Anaphylaxis

Hymenoptera stings can induce allergic and occasionally fatal reactions, and are responsible for significant morbidity and deterioration in health-related quality of life. The diagnostic work-up must consider the medical history of patients, in the context of venom allergy epidemiology and Hymenoptera taxonomy, and the clinical manifestations of the reactions, to channel the available in vivo and in vitro tests towards the most accurate diagnosis and the consequent appropriate management, also considering the risk profile of the patients on a precision-medicine approach. All these aspects are covered by this work that aims at providing an up-to-date review to increase the awareness of this topic among interested stakeholders, like healthcare professionals and political decision makers, who can contribute to the proper immediate and long-term management of venom allergy and anaphylaxis.

Systemic Reactions to Skin Prick Test with Food Allergens in Children

OBJECTIVE

Although skin prick tests (SPTs) are generally considered safe, limited studies have specifically evaluated reactions related to SPTs with all allergens. In contrast to these studies, our aim is to exclusively evaluate systemic reaction (SR) occurrences with food allergens during SPTs in children.

MATERIALS AND METHODS

All patients who underwent skin prick and/or prick-to-prick (PtoP) tests with food allergens at our clinic between January 2010 and January 2020 were included in the study. The occurrence of SR during SPTs was evaluated based on patient records.

RESULTS

The study included 1852 patients, with 57% males and a median age of 31 months (1-210). Skin tests were most commonly conducted for the indication of atopic dermatitis (29.3%). During the study, 11.2% had repeat SPTs for tolerance and a new allergy diagnosis. No local reactions or SRs occurred during SPTs. Among those with PtoP tests, 3 patients (0.16%) experienced SRs-1 had anaphylaxis (0.05%), the rest had angioedema. Legumes and sea bass caused these reactions. In patients with severe index reactions and those who underwent PtoP testing, SR development was significantly higher (P < .001 for both), and anaphylaxis occurrence was significantly higher among those undergoing PtoP testing compared to prick testing alone (P = .03).

CONCLUSION

The prevalence of both SR and anaphylaxis due to SPT with food allergens was found to be quite low in children. However, it is important to consider the possibility of SR development before conducting SPT with food allergens, especially in patients who will undergo the PtoP test and those with severe index reactions. Cite this article as: Karkın G, Ertoy Karagol Hİ, Polat Terece S, Köken G, Yapar D, Bakırtaş A. Systemic reactions to skin prick test with food allergens in children. Turk Arch Pediatr. 2024;59(1):54-59.

Venom Immunotherapy in Patients: Clinical Characteristics, Treatment Outcomes, and Real-Life Safety Data

Objectives

Venom-specific immunotherapy is recognized as the gold standard treatment for honey bee and wasp venom allergies. This study aims to evaluate the clinical characteristics and treatment outcomes of patients diagnosed with honey bee and wasp venom allergies who commenced immunotherapy.

Methods

This study encompasses data from 43 patients who presented with honey bee and wasp venom allergies at Ondokuz Mayis University and initiated venom immunotherapy (VIT). We retrospectively examined the patients' demographic characteristics, history of atopic diseases, allergy history, characteristics of honey bee and wasp venom stings, severity of reactions, laboratory values, administered treatments, and side effects.

Results

Among the 43 patients included in our study, 9 (20.9%) were female, and 34 (79.1%) were male. A history of atopic disease was present in 34.8% of the patients, and a family history in 51.1%. The severity of systemic reactions was evaluated according to Müller's classification, with grade 4 reactions being the most frequent (48.8%). Of the 43 patients who received VIT, 28 (65.1%) were treated for Apis mellifera, 9 (20.9%) for Vespula vulgaris, and 6 (14%) for both species. Twelve patients experienced side effects during VIT, leading to discontinuation in two cases due to patients' reluctance to continue. The remaining 22 patients, who were stung again during or after completing VIT, experienced milder systemic reactions.

Conclusion

This study delineates the demographic and clinical characteristics of patients with honey bee and wasp venom allergies, highlighting the efficacy of VIT treatment. Despite the occurrence of side effects related to VIT, both previous studies and our findings suggest that these side effects are not more severe than systemic reactions resulting from stings. The absence of severe systemic reactions in patients who were stung again during or after receiving VIT underscores the effectiveness of the immunotherapy.

Molecular Profiles of Sensitization to Non-Specific Lipid Transfer Proteins in Lithuania: Single Center Experience

Non-specific Lipid Transfer proteins (nsLTPs) are relevant allergens of several pollens and plant foods. Sensitization to nsLTPs is not typical in our region. Still, it has become an increasingly common cause of IgE-mediated food allergies and food-induced anaphylaxis in Northern Europe in recent decades. No in-depth studies describe the prevalence of sensitization of molecular components to nsLTPs in Lithuania. This study aimed to determine the sensitization profile of atopic patients at the Immunology and Allergy Department of Kauno Klinikos to the components of nsLTPs, using molecular allergen component analysis. Sixty Lithuanian adults with symptoms of allergic rhinitis and/or allergic asthma and/or food allergies were included into the study. Specific immunoglobulin E (IgE) levels were measured using two in vitro techniques: allergen extract and molecular component analysis. Results showed that 25% of subjects were sensitized to nsLTP-containing allergen sources, mostly to Zea m 14, Mal d 3, Vit v 1, and Art v 3. The median amount of total IgE was higher in nsLTP-sensitized patients than in nsLTP-nonsensitized patients. Based on Cohen's Kappa and McNemar tests, the results of allergen extract and component analysis tests do not always agree, especially when we determine the sensitization to allergen sources containing nsLTPs. Molecular allergen component analysis could be the first choice in determining detailed sensitization to nsLTPs in patients who experienced anaphylaxis of unknown origin.

Safety and adverse reactions in subcutaneous allergen immunotherapy: a review

BACKGROUND

Allergen immunotherapy (AIT) is the only treatment which acts on the causes of allergic diseases by modifying their natural history. In the eighties subcutaneous immunotherapy (SCIT) with high biological power allergen extracts caused a number of severe systemic reactions and also fatalities in the UK and the US, resulting in its limitation and in the introduction of other routes of administration. A decisive advance for SCIT safety was understanding that the major cause of mortality was injecting the allergen extract to patients with uncontrolled asthma at the time of injection.

AREAS COVERED

This awareness resulted in a significant decrease in fatalities, but not in their abolition. In 2019, an increase in SCIT-related mortality was observed, suggesting to continue the research for still unidentified factors favoring severe reactions, such as the administration of a wrong extract or of allergen doses higher than listed, unintentional intravenous administration, and missed dose reduction after protracted interruption. Moreover, in the context of the improving of the safety, the role played in tolerance-promoting by adjuvants such as CpG oligodeoxynucleotides has to be taken into account, as well as the potential preventive effect performed by the monoclonal anti-IgE antibody omalizumab against the exacerbation of severe reactions during SCIT.

CONCLUSION

The safety of SCIT is good, but the research to improve it further must continue. In particular, the pathophysiological mechanisms related to AIT for inhalants and for Hymenoptera venom should be studied, based on the evident diversity demonstrated by the complete absence of fatal reactions to Hymenoptera venom immunotherapy from its introduction in comparison with the history of serious and fatal offenses examined in this review.

Comparing the risk of anaphylaxis requiring epinephrine in oral immunotherapy and subcutaneous immunotherapy: A review of recent Canadian real-world literature

Background

The safety of pediatric food oral immunotherapy (Ped-OIT) has been depicted by some as less favorable than subcutaneous immunotherapy (SCIT) owing to the increased number of serious adverse events requiring epinephrine. A review of real-world data comparing Ped-OIT and SCIT safety is necessary to guide shared decision making.

Objectives

Our aim was to compare the safety and adverse event profiles of peanut Ped-OIT and SCIT using Canadian real-word literature.

Methods

We performed a retrospective review of recent Canadian real-world literature on peanut Ped-OIT and SCIT safety and adverse events.

Results

The incidences of systemic reactions requiring epinephrine were 11 in 270 patients (4.07%) and 12 in 41,020 doses (0.029%) in a multicenter study in British Columbia, Alberta, Manitoba, and Nova Scotia studying 270 preschool-age children treated with peanut OIT. Similarly, a multicenter study in South-Western Ontario examining 160 patients between the ages of 1 and 17 years who were treated with peanut OIT showed that the incidences of systemic reactions requiring epinephrine were 5 in 160 patients (3.1%) and 8 in 52,751 doses (0.015%). A single-center retrospective review of 380 patients receiving aeroallergen SCIT showed that the incidences of systemic reactions requiring epinephrine were 28 in 380 patients (7.4%) and 1 in 1047 injection visits (0.095%). These findings are comparable to those of a review of 860 patients in Ontario who received either aeroallergen or venom SCIT, in which the incidence of systemic reaction requiring epinephrine was 10 in 4242 injections (0.24%).

Conclusion

Despite differences in the OIT protocols used and age groups studied, recent real-world data suggest that the safety of preschool peanut OIT or peanut OIT using a slower buildup schedule is comparable to that of SCIT.

Detection of risk factors for systemic adverse reactions to SCIT with natural depot allergen extracts: a retrospective study

BACKGROUND

Some patients seem to show a particular propensity to experience systemic reactions (SR) when undergoing SCIT. This study looked at their features.

METHODS

423 adults submitted to subcutaneous immunotherapy (SCIT) with 583 depot allergens extracts were studied. A "slow" build-up schedule was followed, and maintenance doses were given monthly. No mixtures of allergens were employed; multi-sensitized patients were treated with two extracts at the same time. IgE to pollen allergen components were measured. Patients experiencing several SR and those showing repeated large local reactions preventing up dosing were analyzed.

RESULTS

Altogether, 14% of patients experienced at least 2 SR to SCIT and further 13% repeated local reactions. All SR involved the skin. Eight treatments were stopped. No reactor was using beta-blockers. SR were not associated with pollen season, use of freshly prepared vials, administration of 2 allergens, or extract producer, nor were preceded by large local reactions. Reactors were younger than tolerant subjects (p<0.05), and females were less frequently fully tolerant than males (p<0.001). The multiple regression analysis showed that both ragweed and grass SCIT were significantly associated with adverse reactions (p<0.001). Specific IgE to Amb a 1 or Phl p 1 did not differ statistically between reactors and tolerant subjects, whereas grass pollen-allergic reactors showed higher levels of IgE to Phl p 5. Intolerance did not depend on the number of primary sensitizations or on hypersensitivity to pollen pan-allergens.

CONCLUSION

Young patients or women hypersensitive to grass and ragweed pollen seem at higher risk for SR during SCIT.

Augmented type 2 inflammatory response in allergic rhinitis patients experiencing systemic reactions to house dust mite subcutaneous immunotherapy

BACKGROUND

Subcutaneous immunotherapy (SCIT) can induce systemic reactions (SRs) in certain patients, but the underlying mechanisms remain to be fully elucidated.

METHODS

AR patients who were undergoing standardized HDM SCIT (Alutard, ALK) between 2018 and 2022 were screened. Those who experienced two consecutive SRs were included in the study group. A control group was established, matched 1:1 by gender, age, and disease duration with the study group, who did not experience SRs during SCIT. Clinical and immunological parameters were recorded and analyzed both before SCIT and after 1 year of treatment.

RESULTS

A total of 161 patients were included, with 79 (49.07%) in the study group. The study group had a higher proportion of AR combined asthma (26.8% vs. 51.8%, p < 0.001) and higher levels of sIgE to HDM and HDM components (all p < .001). Serum IL-4 and IL-13 levels in the study group were higher than those in the control group (p < .05). The study group received a lower maintenance dosage of HDM extracts injections than control group due to SRs (50000SQ vs. 100000SQ, p < .05). After 1 year of SCIT, the VAS score, the lung function parameters of asthmatic patients over 14 years old significantly improved in both groups (all p < .05). After a 7-day exposure to 20 μg/mL HDM extracts, the percentages of Th1, Th17, Tfh10, and Th17.1 in PBMCs decreased, while the Tfh13 cells significantly increased in the study group (p < .05).

CONCLUSION

The type 2 inflammatory response is augmented in HDM-induced AR patients who experienced SRs during SCIT. Despite this, SCIT remains effective in these patients when administered with low-dosage allergen extracts.