Cat Allergen Research Articles

Allergocomponent diagnostics in the management of comorbid patients

Polyvalent sensitization (simultaneous formation of antibodies to allergens from several sources, for example, to cat allergens, birch pollen, strawberry allergens), which can occur at any age, concerns a significant number of patients with allergic diseases. The diagnostic search for a causal allergen is difficult in patients with polyvalent sensitization and/or cross-reactions to allergens of unrelated groups of allergens. We have carried out work on the detection of polysensitization in patients by the ALEX2 molecular diagnostic method, which detects specific antibodies to 300 allergens (120 allergens and 180 allergenic molecules + total IgE) in one study. The presented clinical examples clearly show the possibility of identifying the spectrum of causal allergens to clarify the diagnosis, which subsequently makes it possible to prescribe the right treatment to prevent the development of complications, which is especially important for comorbid patients

Allergies to Allergens from Cats and Dogs: A Review and Update on Sources, Pathogenesis, and Strategies

Inhalation allergies caused by cats and dogs can lead to a range of discomforting symptoms, such as rhinitis and asthma, in humans. With the increasing popularity of and care provided to these companion animals, the allergens they produce pose a growing threat to susceptible patients’ health. Allergens from cats and dogs have emerged as significant risk factors for triggering asthma and allergic rhinitis worldwide; however, there remains a lack of systematic measures aimed at assisting individuals in recognizing and preventing allergies caused by these animals. This review provides comprehensive insights into the classification of cat and dog allergens, along with their pathogenic mechanisms. This study also discusses implementation strategies for prevention and control measures, including physical methods, gene-editing technology, and immunological approaches, as well as potential strategies for enhancing allergen immunotherapy combined with immunoinformatics. Finally, it presents future prospects for the prevention and treatment of human allergies caused by cats and dogs. This review will improve knowledge regarding allergies to cats and dogs while providing insights into potential targets for the development of next-generation treatments.

Quantitative filter forensics for allergens and semivolatile organic compounds in residential buildings in Toronto, Canada

Quantitative filter forensics (QFF) is a method for estimating the time-averaged concentration of particle-bound containments using filter metadata and its extracted dust. In this study, QFF was applied to dust samples extracted from four types of HVAC filters deployed in 20 homes from December 2016 to December 2017 in Toronto, Canada. The analysis covered six allergens, eight phthalates, and 12 polycyclic aromatic hydrocarbons (PAHs). The allergen results from four homes showed elevated concentrations of cat and dog allergens (Fel d 1 and Can f 1) in homes with cats or dogs. All eight phthalates were detected, dominated by diisononyl phthalate (DiNP) and bis(2-ethylhexyl) phthalate (DEHP), with median concentrations of 4.27 ng/m³ and 4.20 ng/m³, respectively. All PAHs, except anthracene, were detected in over 50 % of the homes, with benzo[a]pyrene being the most abundant (median concentration of 0.067 ng/m³). Median concentrations of all semivolatile organic compounds (SVOCs) were lower in winter 2016 compared to spring 2017, potentially due to losses of more volatile SVOCs from filters because of higher filtration volumes in winter, in addition to differences in sources and ventilation rates. All phthalate and most PAH concentrations were one to two orders of magnitude lower compared to those found from QFF in apartments in Toronto social housing multi-unit residential buildings (MURB), indicating those with lower socio-economic status (SES) were exposed to higher SVOC concentrations. Occupant density was positively related to most phthalate and specific PAH concentrations, while environmental factors including room temperature, relative humidity, and supply air temperature were not.

Fungi-sensitized individuals have unique profiles where Alt a 1 dominates promoting response to grass, ragweed and cat allergens.

The aim of our work was to determine comprehensively the sensitization profile of patients hypersensitive to fungal allergenic components in the Ukrainian population, identifying features of their co-sensitization to allergens of other groups and establishing potential relationships between causative allergens and their ability to provoke this hypersensitivity. A set of programs was developed using Python and R programming languages, implementing the K-means++ clustering method. Bayesian networks were constructed based on the created clusters, allowing for the assessment of the probabilistic interplay of allergen molecules in the sensitization process of patients. It was found that patients sensitive to fungi are polysensitized, with 84.77% of them having unique allergological profiles, comprising from 2 to several dozen allergens from different groups. The immune response to Alt a 1 may act as the primary trigger for sensitization to other allergens and may contribute to a high probability of developing sensitivity to grasses (primarily to Phl p 2), ragweed extract, and the Amb a 1 pectate lyase, as well as to pectate lyase Cry j 1 and cat allergen Fel d 1. Individuals polysensitized to molecular components of fungi were often sensitive to such cross-reactive molecules as lipocalins Fel d 4 and Can f 6, as well. Sensitivity to Ambrosia extract which dominated in the development of sensitization to ragweed pollen indicating the importance of different allergenic components of this plant's pollen. This hypothesis, along with the assumption that Phl p 2 may be the main trigger for sensitivity to grasses in patients with Alternaria allergy, requires further clinical investigation.

A human monoclonal antibody based immunoenzymetric assay to measure Fel d 1 concentrations in cat hair and pelt allergenic extracts.

In the United States, 19 allergen extracts of different specificities are standardized, which means that their potencies are determined in comparison to a US reference standard. For cat allergen extracts, potency is determined by measuring Fel d 1 content expressed in in Fel d 1 units, and with a unitage that correlates with skin test reactions (bioequivalent allergy units or BAU). Currently, Fel d 1 content is measured with a radial immunodiffusion (RID) assay that uses polyclonal sheep antisera to detect the allergenic protein by producing a white precipitin line in agar gel. However, the RID is considered cumbersome, and the polyclonal sera may qualitatively vary among animals and may recognize epitopes irrelevant to human allergic disease. In this report, we describe a quantitative two-site immunoenzymetric assay (IEMA) for Fel d 1 that uses immobilized capture and soluble biotin-labeled detection Fel d 1-specific human IgE monoclonal antibodies (mAb) that have been class-switched to IgG4. Together, they sandwich Fel d 1 molecules from extracts. Using purified natural Fel d 1 as a calibrator, the historically reported ∼4 micrograms Fel d 1/Fel d 1 unit assignment was directly measured in this mAb-based IEMA at 3.12 ± 0.24 micrograms of Fel d 1 per Fel d 1 unit. This IEMA appears to be equivalent to RID in the measurement of biological potencies of commercial cat hair and cat pelt extracts marketed in the United States.

Why is pet (cat/dog) allergen immunotherapy (AIT) such a controversial topic? Current perspectives and future directions.

Dogs and cats are the most common pets worldwide. In Italy, the prevalence of allergic sensitization to cats and dogs is 16% and 9% respectively. The limited standardization of allergenic extracts, especially for dogs, emphasizes the importance of Component Resolved Diagnosis (CRD) for accurate diagnosis and subsequent prescription of allergen immunotherapy (AIT). However, this low standardization is the main factor contributing to the unsatisfactory clinical efficacy of traditional AIT, AIT with modified allergens, and intralymphatic allergen-specific immunotherapy (ILAIT). Emerging immunological approaches, particularly for controlling the primary cat allergen, show promise but are hindered by high costs (e.g., use of anti-Fel d 1 monoclonal antibodies in humans) or by exclusively targeting Fel d 1 produced by one's own animal (e.g., immunizing cats to induce neutralizing antibodies against Fel d 1 or including an egg product with anti Fel d 1 IgY antibodies in feline diet). Further studies are imperative for standardizing pet allergens, enhancing the efficacy of various AIT modalities, and exploring other immunological approaches, to optimize the relationship between pets and their owners and prevent distressing "forced removals".

Advancing diagnostic precision: Unveiling sensitization relationships between cat, dog, and horse allergen molecules.

Recent advancements in molecular diagnostics have unveiled a multitude of allergen molecules (AMs) associated with animal sensitizations, revealing significant cross- and co-sensitization patterns among these seemingly distinct allergens. We investigated the sensitization profiles of 120 children, sensitized to at least one of the 14 AMs from cat, dog, or horse using the Alex test, employing correlations and hierarchical clusters to explore relationship between sensitizations. Sensitizations to Fel d 1, Can f 4/5, and Equ c 4 differ from other cat, dog, and horse AM sensitizations, suggesting they may represent genuine sensitizations for their respective animals. High correlations were observed among various AMs, including lipocalins (Can f 1/2/6, Fel d 4/7, and Equ c 1), serum albumins (Fel d 2, Can f 3, and Equ c 3), and uteroglobins (Fel d 1 and Can f_Fd1). Hierarchical clustering of sensitizations identified two similarity clusters and one dissimilarity cluster, providing an estimation of the likelihood of cross-reactivity. Additionally, our method facilitated speculation regarding cross-, co-, or genuine sensitization. Moreover, we noted a potential increase in the number and level of sensitized animal AMs concurrent with increased sensitization to other aeroallergens with advancing age. No significant difference was detected for the presence or absence of various types of allergic comorbidities. Correlations and hierarchical clustering can unveil the extent and magnitude of cross-, co-, and genuine sensitization relationships among animal AMs. These insights can be leveraged to enhance artificial intelligence algorithms, improving diagnostic accuracy through the integration of other measures of sensitization.

Persistent cat ownership and asthma in a longitudinal study of Puerto Rican youth

BackgroundEpidemiologic studies have reported conflicting findings for cat or dog exposure and childhood asthma. No study has evaluated whether persistent pet exposure from early life to school age is associated with asthma or allergic sensitization in youth. ObjectiveTo evaluate whether persistent ownership of a cat or a dog throughout childhood is associated with asthma in Puerto Rican youth, a group disproportionately affected with asthma. MethodsProspective study of 384 youth who completed a baseline visit at ages 6 to 14 years and a second visit at ages 9 to 20 years. Persistent cat or dog ownership was defined as ownership of a cat or a dog in early life (during pregnancy or the first year of life) at either study visit (at school age). An allergen-specific IgE result was considered positive if more than or equal to 0.35 IU/mL. Logistic regression was used for the multivariable analysis of asthma and allergic sensitization. ResultsIn an analysis adjusting for household income, family history of atopy, persistent overweight or obesity, a persistent unhealthy diet, the time interval between study visits, and other covariates, persistent cat ownership was significantly associated with 68% reduced odds of asthma (95% CI for odds ratio = 0.11-0.92) but not with any allergic sensitization or sensitization to cat allergen. In contrast, persistent dog ownership was not significantly associated with asthma or allergic sensitization. ConclusionAmong school-aged Puerto Rican youth followed for an average of 5 years, persistent cat ownership from early life to school age was inversely associated with asthma.

Rhinoconjunctivitis severity induced by cat exposure influences early and late asthmatic responses: Evidence from an environmental exposure chamber.

The impact of allergic rhinoconjunctivitis on the early (EAR) and late asthmatic response (LAR) has yet to be assessed during optimal allergen exposure conditions. We aimed to assess predictive factors of the EAR and LAR and to evaluate the relation between rhinitis, conjunctivitis and asthma induced by cat allergen exposure in an environmental exposure chamber (EEC). Data from two cohort studies involving asthmatic patients with cat allergy who performed a cat allergen exposure challenge in ALYATEC EEC were analysed. Spirometry, visual analogue scale (VAS) for asthma, VAS for rhinitis, Total Nasal Symptoms Score, Total Ocular Symptoms Score (TOSS), Rhinoconjunctivitis Total Symptoms Score and Abelson score were used to assess asthma, rhinitis and conjunctivitis during and after exposure. An EAR occurred in 65.1% of patients, 32.1% of whom had a LAR. The diameter of the prick test to cat allergens and non-specific bronchial hypersensitivity level were independent risk factors for EAR (p < .05). No independent risk factors for LAR were identified. Rhinoconjunctivitis severity during exposure correlated with the asthma VAS during EAR and LAR (p < .05). Allergen exposure time needed to trigger an EAR correlated with the Abelson score during exposure (p < .05). The asthma VAS and TOSS during exposure correlated with faster LAR occurrence (p < .05). Prick test size and non-specific bronchial hypersensitivity level were confirmed as independent predictive factors of EAR during allergen exposure in an EEC. This study demonstrated the relation between the severity of rhinitis, conjunctivitis and asthma induced by allergen exposure for both EAR and LAR.

ПРОФИЛИ МОЛЕКУЛЯРНОЙ СЕНСИБИЛИЗАЦИИ К АЛЛЕРГЕНАМ ПУШНЫХ ЖИВОТНЫХ У ПАЦИЕНТОВ РОССИЙСКОЙ ФЕДЕРАЦИИ

Molecular sensibilization patterns have not been yet described for the Russian population, which makes it difficult to develop prevention, elimination and treatment methods for patients with allergic pathology. The purpose of this research was to analyze patterns of sensibilization to components of fur animal allergens in patients examined in order to exclude the sensibilization. Materials and methods used: results of 1113 Immuno Solid-phase Allergen Chip (ISAC) in patients with suspected atopy were analyzed. In all patients, sIgE concentrations to allergenic components of fur animals were determined. Results: 468 (58.21%) of 1113 were found to have sensibilization to fur animal allergens. Of these, 396 (84.62%) were sensibilized to the cat, 277 (59.19%) to the dog, 98 (20.94%) to the horse, and 26 (5.55%) to the mouse. sIgE to Fel d 1 was determined in 90.91% of patients with cat sensibilization, and the median concentration of sIgE to Fel d 1 was higher than to Fel d 2 (p=0.011) and Fel d 4 (p&lt;0.001) (5.4 [1,7; 15]). ISU-E, sIgE to Can f 1 was detected in 73.29%, to Can f 2 - in 18.05%, to Can f 5 - in 41.52% of patients sensibilized to dogs. Among children under 9 y/o, the frequency of detection of sensitization to Can f 5 was less frequent than in the group of children aged over 10 y/o and adults (p&lt;0.001). Conclusion: the Russian population is characterized by a high prevalence of sensibilization to fur animal allergens. Most patients had polysensibilization to components of cat (Fel d 1) and dog (Can f 1, 2 and 5) allergens. It was revealed that Can f 2 has a higher allergenic potential, which in its turn allows it to be identified as a major dog allergen. 92.55% of patients with sensibilization to Fur-bearing animals have an increased risk of developing asthma.

Evaluation of anti-Fel d 1 IgY ingredient for pet food on growth performance in kittens.

The domestic cat (Felis catus) is one of the most common pets. Worldwide, approximately one in five adults are sensitive to cat allergens. The major cat allergen is the secretoglobulin Fel d 1, which is primarily produced in the salivary and sebaceous glands. Chickens produce IgY antibodies, which are similar in structure to mammalian IgG. When chickens are exposed to Fel d 1, anti-Fel d 1-specific IgY (AFD1) is produced and is naturally concentrated in egg yolk. The aim of this study was to evaluate the tolerability, effects on growth and food consumption, and potential adverse effects of a chicken egg product ingredient containing AFD1 in kittens. This was a blinded, controlled study. Twenty-seven (27) eight-week old kittens were randomly assigned to three feeding groups containing 0 ppm AFD1 (Group 0), 8 ppm AFD1 (Group 1), and 16 ppm AFD1 (Group 2) for 84 days. Veterinary exams and bloodwork were performed on Day 42 and Day 84, and body weight and body condition score (BCS) were monitored weekly. Throughout the study, there were no signs of nutritional deficiency or adverse clinical events in any of the subjects. Administration of a chicken egg product ingredient containing AFD1 in the diet (whether in coating or combination of coating and top dress) had no significant effect on body weight nor food consumption, and all subjects maintained a healthy Body Condition Score (BCS) throughout the study. Moreover, there were no biologically significant differences in the mean clinical chemistry and hematology parameters. This study demonstrated that a diet formulated to contain up to 16 ppm AFD1, included in the coating and the top-dress of dry kitten food, was well tolerated, promoted adequate growth, and exhibited no adverse effects.

Molecular sensitization and epitope prediction of cat allergens

Molecular sensitization and epitope prediction of cat allergens

Relationship between indoor inhalant allergen concentrations, serum IgE, and allergic diseases: A cross-sectional study from the NHANES 2005–2006 program

This research analyzed data from 5106 participants in the National Health and Nutrition Examination Survey 2005–2006 to explore the link between indoor allergen concentrations, serum IgE levels, and allergic diseases. The study found that 14.9% of participants reported having asthma, with significant differences noted in the concentrations of certain indoor allergens, specifically dust dog, mite, and cat allergens, between asthma and non-asthma groups. Furthermore, positivity rates for inhalant allergen-specific IgE and total IgE were higher in the asthma group. However, the correlations between most inhalant allergen IgE, including total IgE, and indoor allergen concentrations were very weak. These findings suggest that the relationship between indoor allergen concentrations and asthma incidence is complex, indicating a potential need for personalized allergen prevention strategies based on disease type and patient sensitization.

Artificial intelligence-driven design of the assembled major cat allergen Fel d 1 to improve its spatial folding and IgE-reactivity

BackgroundCat-derived allergens are considered as one of the most common causes of allergic diseases worldwide. Fel d 1 is a major cat allergen and plays an important role in immunoglobulin E (IgE)-reaction diagnosis. However, the two separate chains of Fel d 1 exhibited lower IgE-reactivity than its complete molecule of an assembled form, which makes it difficult to efficiently prepare and limits the application of Fel d 1 in molecular diagnosis of cat allergy. MethodsWe first applied artificial intelligence (AI) based tool AlphaFold2 to build the 3-dimensional structures of Fel d 1 with different connection modes between two chains, which were evaluated by ERRAT program and were expressed in Escherichia coli. We then calculated the expression ratios of soluble form/inclusion bodies form of optimized Fel d 1. The Circular Dichroism (CD), High Performance Liquid Chromatography-Size Exclusion Chromatography (HPLC-SEC) and reducing/non-reducing SDS-PAGE were performed to characterize the folding status and dimerization of the optimized fusion Fel d 1. The improvement of specific-IgE reactivity to optimized fusion Fel d 1 was investigated by enzyme linked immunosorbent assay (ELISA). ResultsAmong several linkers, 2 × GGGGS got the highest scores, with an overall quality factor of 100. The error value of the residues around the junction of 2 × GGGGS was lower than others. It exhibited highest proportion of soluble protein than other Fel d 1 constructs with ERRAT (GGGGS, KK as well as direct fusion Fel d 1). The results of CD and HPLC-SEC showed the consistent folding and dimerization of two fused subunits between the optimized fusion Fel d 1 and previously well-defined direct fusion Fel d 1. The overall IgE-binding absorbance of optimized fusion Fel d 1 tested by ELISA was improved compared with that of the direct fusion Fel d 1. ConclusionWe firstly provided an AI-design strategy to optimize the Fel d 1, which could spontaneously fold into its native-like structure without additional refolding process or eukaryotic folding factors. The improved IgE-binding activity and simplified preparation method could greatly facilitate it to be a robust allergen material for molecular diagnosis of cat allergy.

Individual wearable air purifier protects against pollen, house dust mite, and cat allergens: Report from anallergen exposure chamber.

Evaluation of a new individual wearable air purifier (Respiray Wear A+) for birch pollen, house dust mite (HDM), and cat-allergic rhinoconjunctivitis (ARC) patients in a standardized allergen exposure chamber (AEC). Eligible allergic patients were exposed to birch pollen, HDM raw material, and cat allergen in an AEC for 60 minutes without (V1) and with (V3) the use of the Respiray device. Nasal, ocular, bronchial, and other symptoms were rated by the patients every 10 minutes, and their wellbeing, peak nasal inspiratory flow (PNIF), and lung function parameters were assessed every 30 minutes. The primary endpoint was the change in the median of the total symptom score (TSS) at V3 compared to V1 at 60 minutes of exposure. The secondary endpoints consisted of the total nasal symptom score (TNSS) and total eye symptom score (TESS). 23 patients with birch pollen allergy, 37 patients with HDM allergy, and 41 patients with cat allergy were included in the analysis. Significant reduced symptom scores of ~49% were observed when using Respiray Wea A+ under birch pollen exposure (p<0.05) in the primary endpoint TSS (V3 2.43 compared to V1 4.78). An 48% reduction of symptoms was seen in TSS in case of HDM exposure (V3 3.59; V1 6.92, (t-test: p<0.01)) and the highest reduction of TSS (60%) under Respiray A+ using cat allergens (V3 2.95, V1 7.44, (t-test p<0.01) after 60 minutes of exposure. The personal wellbeing revealed clinically meaningful improvements over time in all three studies which manifested in a lower symptom increase during the final allergen exposures. The individual wearable air purifier Respiray Wear A+ protects significantly against airborne pollen, HDM, and cat allergens and may be a very useful device for avoiding indoor allergens in a new way.

The Impact of the Pandemic on Cat and Dog Allergies.

The impact of the COVID-19 pandemic on allergic patients is not clearly understood. The aim of this study is to investigate the changes in sensitivity to cat and dog allergens in patients with respiratory allergies in Istanbul during the COVID-19 pandemic. Before the pandemic (March 2018 - March 2020) and during and after the pandemic (March 2020 - March 2022), a total of 5499 patients who underwent skin testing were retrospectively evaluated. The patients' age, gender, diagnosis, total IgE, and eosinophil values were recorded. Patients were divided into two groups: 2-6 years old and 7 years and older. The frequency of sensitization to cats and dogs was investigated in both groups before and after the pandemic. The median age of the 5499 children included in the study was 77 months, with a range of 2 to 221 months. Furthermore, 55.7% of the children were male. Of the children, 59.1% were examined before the pandemic, and 40.9% during and after the pandemic. During the examinations, allergic rhinitis was identified in 1628 children (29.6%), asthma in 1829 children (33.3%), and both asthma and allergic rhinitis in 2042 children (37.1%). Allergies to cats were found in 247 children (4.5%), and to dogs in 166 children (3.0%). When comparing the age groups, the frequency of cat allergy in the 7-years and older group was found to have decreased compared to the pre-pandemic period, and the statistical difference was close to significance (p=0.08). However, regarding dog allergy, in the 7 years and older group, the sensitivity to dogs, which was 5.6% before the pandemic, had decreased to 2.6% during the pandemic, and this decrease was found to be statistically highly significant (p<0.001). Environmental allergen exposure has a significant impact on the phenotype of allergic diseases. Changes in patients' lifestyles and increased time spent at home during the pandemic may have led to a decrease in contact with outdoor cat and dog allergens, resulting in a reduced frequency of cat and dog sensitivity. Additionally, the introduction of mask-distance-handwashing/disinfection rules during the pandemic is believed to have reduced contact with cat and dog allergens, potentially contributing to a decrease in allergy frequency.

Purification of living environments using photocatalysts: inactivation of microorganisms and decomposition of allergens.

Many emerging and re-emerging infectious diseases are prevalent, and the number of patients with allergies is increasing. Therefore, the importance of purifying the living environment is increasing. Photocatalysts undergo extreme redox reactions and decompose organic matter upon exposure to the excitation light. In contrast to ultraviolet light and disinfectants, which are standard methods for inactivating viruses and eliminating microorganisms, photocatalysts can decompose toxic substances, such as endotoxins and allergens, rendering them harmless to the human body. Photocatalysts have attracted significant attention as potential antiviral and antimicrobial agents. This review outlines the antiviral, antimicrobial, and anti-allergenic effects of photocatalysts. Especially, we have discussed the inactivation of SARS-CoV-2 in liquids and aerosols, elimination of Legionella pneumophila in liquids, decomposition of its endotoxin, decomposition of cat and dog allergens, and elimination of their allergenicity using photocatalysts. Furthermore, we discuss future perspectives on how photocatalysts can purify living environments, and how photocatalytic technology can be applied to companion animals and the livestock industry.

ENVIRONMENTAL ALLERGENS AND ASTHMA

Exposure to inhalant allergens is associated with allergen-specific sensitization, a risk factor for the development of bronchial asthma, along with genetic and environmental factors. Early life exposure to mites increases the risk of sensitization and development of asthma in high-risk children. The same would occur with cat allergen levels inside the house and increased risk of sensitization in preschool and school. On the other hand, early contact with multiple microorganisms contributes to preventive immunomodulation by inducing tolerance to allergens. Climate change has been shown to increase the potency of allergenic pollens and the severity of exposure to fungi, which could partly explain the increase in allergic diseases in recent years. There is much evidence regarding exposure to allergens in sensitized asthmatic children and asthma exacerbation. It is essential to know which allergens the patient is sensitized to in order to implement environmental avoidance measures. This article summarizes an update on the mechanisms of sensitization to inhalant allergens in asthmatic children and its relationship with climate change and asthma severity. The main prevention measures, environmental control and the role of immunotherapy are also presented.

Residual profiles and health risk of indoor allergens in China

Exposure to indoor allergens is a principal risk factor for allergic diseases. However, most of the previous studies on indoor allergens focused on very limited kinds of allergens in China. Knowledge of the simultaneous exposure to multiple allergens is still lacking. In this study, the residual profiles of 8 allergens were investigated in 166 dust samples from 11 cities in China. The house dust mite allergens including Der p 1, Der f 1, and Der 2 were detected in the range of <0.02–283.83 μg/g dust. The concentrations of dog allergen Can f 1 and cat allergen Fel d 1 varied widely, from <0.84–22,896.46 μg/g dust for Can f 1 and from <0.02–6298.96 μg/g dust for Fel d 1. Cockroach allergen Bla g 2 was detected in 68% of the samples but at a low level with a maximum of 9.44 μg/g dust. Comparatively low detection frequencies were found for mouse allergen Mus m 1 as 37% and for fungi allergen Asp f 2 as 24%. The frequency of cleaning sheets/bedding was negatively correlated to the levels of house dust mite allergens. The presence of pets indoors was associated with higher levels of pet allergens and lower levels of house dust mite allergens and cockroach allergen. Risk evaluation reveals that at least 4 allergens were found in more than 80% of the rooms and more than 2 allergens with median/high risk were detected in 42% of the rooms, indicating that simultaneous exposure to multiple allergens is prevalent in China.

Increasing Prevalence of Sensitization to Cat/Dog Allergens in the COVID-19 Pandemic

Introduction: Cat and dog allergens are common indoor triggers for respiratory allergies such as allergic rhinitis and asthma. This study aims to evaluate the prevalence of cat and dog allergies in adults and analyze changes during the COVID-19 pandemic. Methods: We retrospectively analyzed the medical records of 8,102 patients who visited an allergy clinic and underwent skin prick testing (SPT) from March 2018 to March 2022: 2 years before and 2 years during the pandemic. Demographic information, clinical attributes, and laboratory results were examined based on patient records. Results: Of 8,102 SPTs performed, 400 (4.9%) were sensitized to cat allergen and 289 (3.6%) to dog allergen. Allergic rhinitis was the predominant clinical diagnosis in both groups. Of the 400 subjects exposed to cats, 240 (60%) experienced allergic symptoms, while of the 289 subjects exposed to dogs, 65 (22.5%) experienced allergic symptoms during exposure. Within the cat-sensitized group, anaphylaxis was observed in 5 patients (1.3%), while no cases of anaphylaxis were reported in the dog-sensitized group. Compared to the pre-pandemic period, patients presenting during the pandemic had higher rates of cat and dog sensitization (5.7% vs. 4.1%; p < 0.05, 5.2% vs. 1.7%; p < 0.05). Conclusion: During the COVID-19 pandemic, there was an increase in cat and dog allergies among adults. Increased exposure to pet antigens, both directly and indirectly, has resulted in more people becoming sensitized to cats or dogs.