Do hypoallergenic cats and dogs exist?

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

Introduction

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.

Methods

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.

Results

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.

Discussion

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.

Horse allergy: Curly Horses can mediate immune tolerance

American Bashkir Curly Horses are claimed to be hypoallergenic, but this has not been clinically proven. In the present study, the effect of exposure to Curly Horses was investigated in 141 patients allergic to horses by measuring their lung function and nasal patency during Curly Horse contact. Continuous contact with Curly Horses, including riding and brushing, decreased the allergic riders' reactivity as measured by FEV1, PEF, and PNIF. Subsequent visits (up to 40 or more hours of riding) further reduced reactivity to the Curly Horses. Allergic events to horses occurred only in 72 out of 1312 riding hours, mainly in the first ten riding hours.In 41 out of the 141 patients, it was further investigated whether repeated exposure to Curly Horses could induce tolerance to other horses. Patients in the tolerance induction study were tested annually for horse allergy using a nasal provocation test. The tolerance induction study showed that exposure to Curly Horses induced immune tolerance to other horses in 88% of patients who completed the study.To understand the mechanism causing hypoallergenicity, we performed IgE immunoblots to determine whether Curly Horse hairs contain IgE binding proteins. However, no differences in IgE reactivity were found between Curly and non-Curly Horses. Moreover, the immune tolerance induction study patients did not show decreased IgE reactivity to hairs from Curly or non-Curly Horses even though patients had developed tolerance. However, we did find increasing levels of anti-horse IgG antibodies in the study patients.Overall, our data strongly suggests that continuous exposure to Curly Horses can induce immune tolerance, rendering these patients non-reactive to horses. The reason for the reduced clinical allergenicity of Curly Horses remains unclear, but the data suggest that blocking IgG antibodies may be of importance for immune tolerance development.

Dissecting Airborne Allergens

Asthma is a heterogeneous and very complex group of diseases, and includes different clinical phenotypes depending on symptoms, progression, exacerbation patterns, or responses to treatment, among other characteristics. The allergic phenotype is the most frequent, especially in pediatric asthma. It is characterized by sensitization (the production of specific IgEs) to allergens and frequent comorbidity with rhinitis as well as atopic dermatitis. Given the complexity of allergic asthma, knowledge of it must be approached from different points of view: clinical, histological, physiological, epidemiological, biochemical, and immunological, among others. Since partial approaches do not allow for the understanding of this complexity, it is necessary to have multidimensional knowledge that helps in performing the optimal management of each case, avoiding a "blind men and elephant parable" approach. Allergens are antigens that trigger the production of specific IgE antibodies in susceptible individuals, who present symptoms that will depend on the type and intensity of the allergenic load as well as the tissue where the interaction occurs. Airborne allergens cause their effects in the respiratory tract and eyes, and can be indoor or outdoor, perennial, or seasonal. Although allergens such as mites, pollens, or animal dander are generally considered single particles, it is important to note that they contain different molecules which could trigger distinct specific IgE molecules in different patients. General practitioners, pediatricians, and other physicians typically diagnose and treat asthma based on clinical and pulmonary function data in their daily practice. This nonsystematic and nonexhaustive revision aims to update other topics, especially those focused on airborne allergens, helping the diagnostic and therapeutic processes of allergic asthma and rhinitis.

The importance of skin prick test in differentiating cat sensitivities and allergies in children

BACKGROUND

The incidence of cat allergies in children has increased over the years. Children with cat allergies have mostly reported respiratory symptoms. The skin prick test (SPT) is the most preferred method to demonstrate sensitization to allergens. However, not all children who develop cat sensitization due to environmental exposure become allergic to cats. In our study, we aimed to determine the frequency of sensitization to cat and cat allergy, cat-related symptoms, and the cut-off value for the SPT that may indicate cat allergy.

METHODS

Patients aged 2-18 years, who applied to the Health Sciences University İzmir Dr Behçet Uz Pediatrics and Surgery Training and Research Hospital and Balıkesir University Application and Research Hospital Pediatric Allergy outpatient clinics between January 01, 2019 and December 31, 2020, were included in the study. Patients who underwent SPT and found to be sensitized to cat allergen, were evaluated retrospectively. Clinical and laboratory findings of the patients were recorded. Receiver operating characteristics (ROC) analysis was performed to determine the cut-off value for the SPT.

RESULTS

Sensitization to cat was detected in 140 (4%) out of 3499 patients who underwent SPT. The median age of the patients was 12 years (min-max: 5-18) and 67.1% were male. Eighty-eight (62.9%) patients were symptomatic upon contact with cats, predominantly with nasal symptoms. These patients had significantly larger cat SPT wheal size than asymptomatic patients. The cut-off value was determined as 5.5 mm with a sensitivity of 72.7% and a specificity of 61.5% (95% CI, 60.5%-78.4%). Symptoms resolved in about half of our patients by reducing contact with cats.

DISCUSSION

The present study is the first to report the frequency and clinical findings of cat sensitizations and allergies in Turkish children. For effective treatment, cat allergy must be diagnosed. In this regard, the use of a practical, readily accessible 5.5 mm cut-off point on the SPT may be helpful.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Human allergy to cats: A review for veterinarians on prevalence, causes, symptoms and control

PRACTICAL RELEVANCE

Human allergy to cats affects a substantial and growing proportion of the global population, and cat allergy is regarded as the third most common cause of human respiratory allergies, and the second most common indoor cause. Veterinarians will frequently encounter owners who are cat-allergic, and having an understanding of this disease and the methods available to help control the allergy will assist them in giving appropriate advice, alongside human healthcare professionals.

AIM

The aim of this review is to summarise currently available data on the prevalence, causes, symptoms and control of human allergy to cats. In terms of managing cat allergy, the emphasis is on reviewing current and emerging modalities to reduce environmental exposure to cat allergens rather than on pharmacotherapy or immunotherapy, as it is in these areas in particular that the veterinarian may be able to offer help and advice to complement that of human healthcare professionals.

EVIDENCE BASE

The information in this review is drawn from the current and historical literature on human allergy to cats, and approaches to reduce exposure to cat allergens and manage symptoms of cat allergy.

Hello, kitty: could cat allergy be a form of intoxication?

Background

The relationship between slow loris (Nycticebus spp.) venom (BGE protein) and the major cat allergen (Fel d 1) from domestic cat (Felis catus) is known for about two decades. Along this time, evidence was accumulated regarding convergences between them, including their almost identical mode of action.

Methods

Large-scale database mining for Fel d 1 and BGE proteins in Felidae and Nycticebus spp., alignment, phylogeny proposition and molecular modelling, associated with directed literature review were assessed.

Results

Fel d 1 sequences for 28 non-domestic felids were identified, along with two additional loris BGE protein sequences. Dimer interfaces are less conserved among sequences, and the chain 1 shows more sequence similarity than chain 2. Post-translational modification similarities are highly probable.

Conclusions

Fel d 1 functions beyond allergy are discussed, considering the great conservation of felid orthologs of this protein. Reasons for toxicity being found only in domestic cats are proposed in the context of domestication. The combination of the literature review, genome-derived sequence data, and comparisons with the venomous primate slow loris may point to domestic cats as potentially poisonous mammals.

Indoor Environmental Interventions for Furry Pet Allergens, Pest Allergens, and Mold: Looking to the Future

Over the last 2 to 3 decades, significant advances have been made in understanding the role that indoor allergen exposures play with regard to respiratory health. Multiple studies have confirmed that sensitization and exposure to indoor allergens can be a risk factor for asthma morbidity. Environmental interventions targeting key indoor allergens have been evaluated with the aims of examining their causal effects on asthma-related outcomes and identifying clinically efficacious interventions to incorporate into treatment recommendations. Historically, it appeared that the most successful intervention, as performed in the Inner-City Asthma Study, was individually tailored, targeting multiple allergens in a predominantly low-income, minority, and urban pediatric population. Recent studies suggest that single-allergen interventions may be efficacious when targeting the most clinically relevant allergen for a population. In this article, we review recent literature on home environmental interventions and their effects on specific indoor allergen levels and asthma-related outcomes.

Keep the cat, change the care pathway: A transformational approach to managing Fel d 1, the major cat allergen

Background

Allergies to cats are the most common animal‐origin allergy, and affect approximately 1 in 5 adults worldwide. The prevalence of allergy to furry animals has been increasing, and allergy to cats is a major risk factor for the development of asthma and rhinitis. The diagnosis of cat allergy is now well established. The exact significance of component‐resolved diagnosis in the diagnosis of cat allergy remains to be fully understood. Allergen avoidance is effective but often has a psychologic impact. Allergen immunotherapy is not well demonstrated. There is a need for innovative approaches to better manage cat allergens. Next‐generation care pathways for asthma and rhinitis will define the place of cat allergen avoidance.

Methods and Results

This manuscript, based on content presented at the European Academy of Allergy and Clinical Immunology Congress 2019, provides information on the prevalence and impact of cat allergies and the molecular biology of Fel d 1, the major cat allergen.

Discussion

The authors present the scientific basis of a novel care pathway that utilizes anti‐Fel d 1 IgY antibodies to safely and effectively neutralize Fel d 1 after its production by the cat but before human exposure.

Conclusion

Efficacy of a feline diet with an egg product ingredient containing anti‐Fel d 1 IgY antibodies was demonstrated in vitro, ex vivo, and in vivo, and further validated by a pilot exposure study involving cat‐allergic human participants.

Influence of time and phenotype on salivary Fel d1 in domestic shorthair cats

Objectives

Fel d1 is a major allergen that may affect humans sensitive to cat allergens, and it can be detected in the saliva and on the hair of cats. We studied the variability of salivary Fel d1 in typical house cats (ie, neutered domestic shorthair cats) and the factors that could be associated with that variability.

Methods

Saliva samples were collected from 64 cats, twice daily, every other day, for a year, at two locations (Missouri, USA, and Ontario, Canada). Salivary Fel d1 levels were measured using an immunoassay. Correlations and linear mixed-effects model analyses were run to assess which factors significantly affected the Fel d1 levels.

Results

Salivary Fel d1 levels varied significantly both within and among cats. Cat averages over the year ranged from 0.4–35 µg/ml, and a higher average correlated with a higher SD (P <0.001). The first collection of the day tended to be higher than the afternoon collection (P <0.001). Sex, coat color or body size did not relate to cats’ average Fel d1 production, but older cats tended to have lower salivary Fel d1 levels (P <0.001). Fel d1 levels from four samples were reliable in identifying cats producing stable low levels of Fel d1.

Conclusions and relevance

We observed a wide and continuous range of salivary Fel d1 production in domestic shorthair cats. In particular, a subset of cats had stable low levels throughout the course of the year, and they can be identified by analyzing a few saliva samples rather than their physical appearance.

Consensus document on dog and cat allergy

The prevalence of sensitization to dogs and cats varies by country, exposure time and predisposition to atopy. It is estimated that 26% of European adults coming to the clinic for suspected allergy to inhalant allergens are sensitized to cats and 27% to dogs. This document is intended to be a useful tool for clinicians involved in the management of people with dog or cat allergy. It was prepared from a consensus process based on the RAND/UCLA method. Following a literature review, it proposes various recommendations concerning the diagnosis and treatment of these patients, grounded in evidence and clinical experience. The diagnosis of dog and cat allergy is based on a medical history and physical examination that are consistent with each other and is confirmed with positive results on specific IgE skin tests. Sometimes, especially in polysensitized patients, molecular diagnosis is strongly recommended. Although the most advisable measure would be to avoid the animal, this is often impossible and associated with a major emotional impact. Furthermore, indirect exposure to allergens occurs in environments in which animals are not present. Immunotherapy is emerging as a potential solution to this problem, although further supporting studies are needed.

Immunotherapy for Cat Allergies: A Potential Strategy to Scratch Back

Cat allergies are a common and costly problem in the United States. Various drug and nondrug therapies exist to alleviate and control symptoms once allergic disease has developed. However, these therapies are often ineffective or do not address the underlying condition itself. Immunotherapy is an option for patients when symptoms are not adequately controlled by medications and/or avoidance measures, when adverse effects of medications are unacceptable, or when the patient wants to reduce their long-term use of medication. The purpose of this article is to describe the efficacy and safety of immunotherapy when used to prevent or treat cat allergies.

Indoor Air Quality

Many health care providers are concerned with the role environmental exposures play in the development of respiratory disease. While most individuals understand that outdoor air quality is important to their health status, many are unaware of the detrimental effects indoor air pollution can potentially have on them. The Environmental Protection Agency (EPA) regulates both outdoor and indoor air quality. According to the EPA, indoor levels of pollutants may be up to 100 times higher than outdoor pollutant levels and have been ranked among the top 5 environmental risks to the public. There has been a strong correlation between air quality and health, which is why it is crucial to obtain a complete environmental exposure history from a patient. This article focuses on the effects indoor air quality has on the respiratory system. Specifically, this article will address secondhand smoke, radon, carbon monoxide, nitrogen dioxide, formaldehyde, house cleaning agents, indoor mold, animal dander, and dust mites. These are common agents that may lead to hazardous exposures among individuals living in the United States. It is important for health care providers to be educated on the potential risks of indoor air pollution and the effects it may have on patient outcomes. Health problems resulting from poor indoor air quality are not easily recognized and may affect a patient's health years after the onset of exposure.

Environmental triggers and avoidance in the management of asthma

Identifying asthma triggers forms the basis of environmental secondary prevention. These triggers may be allergenic or nonallergenic. Allergenic triggers include indoor allergens, such as house dust mites (HDMs), molds, pets, cockroaches, and rodents, and outdoor allergens, such as pollens and molds. Clinical observations provide support for the role of HDM exposure as a trigger, although avoidance studies provide conflicting results. Molds and their metabolic products are now considered to be triggers of asthma attacks. Pets, dogs, and especially cats can undoubtedly trigger asthmatic symptoms in sensitized subjects. Avoidance is difficult and rarely adhered to by families. Cockroach allergens contribute to asthma morbidity, and avoidance strategies can lead to clinical benefit. Mouse allergens are mostly found in inner-city dwellings, but their implication in asthma morbidity is debated. In the outdoors, pollens can induce seasonal asthma in sensitized individuals. Avoidance relies on preventing pollens from getting into the house and on minimizing seasonal outdoor exposure. Outdoor molds may lead to severe asthma exacerbations. Nonallergenic triggers include viral infections, active and passive smoking, meteorological changes, occupational exposures, and other triggers that are less commonly involved. Viral infection is the main asthma trigger in children. Active smoking is associated with higher asthma morbidity, and smoking cessation interventions should be personalized. Passive smoking is also a risk factor for asthma exacerbation. The implementation of public smoking bans has led to a reduction in the hospitalization of asthmatic children. Air pollution levels have been linked with asthmatic symptoms, a decrease in lung function, and increased emergency room visits and hospitalizations. Since avoidance is not easy to achieve, clean air policies remain the most effective strategy. Indoor air is also affected by air pollutants, such as cigarette smoke and volatile organic compounds generated by building and cleaning materials. Occupational exposures include work-exacerbated asthma and work-related asthma.

Environmental Risk Factors in Patients with Noninvasive Fungal Sinusitis

Objective. The aim of our study was to try to determine the possible environmental risk factors for noninvasive fungal sinusitis in Egyptian patients. Methods. This is a prospective epidemiological case control study on the environmental risk factors of noninvasive fungal sinusitis. It included 60 patients and 100 age and sex matched controls. Results. There was a statistically significant relation between apartment floor, surface area, exposure to dust, exposure to cockroaches, poor air conditioning, and fungal sinusitis. Yet, no statistical significance was found between allergy related occupations, exposure to animals or plants, although their percentages were higher among cases, smoking, and urban or rural residence. Conclusion. We suggest that for patients with noninvasive fungal sinusitis a change in their living environment must be implied with better exposure to sunlight, larger well ventilated homes, proper cleaning of dust and cockroach extermination, and if possible the judicious use of air conditioners.

Recent Understandings of Pet Allergies

Allergic reactions to pets have been recognized for at least a hundred years. Yet our understanding of the effects of all of the interactions between pet exposures and human immune responses continues to grow. Allergists, epidemiologists, and immunologists have spent years trying to better understand how exposures to pet allergens lead to allergic sensitization (the production of allergen-specific immunoglobulin class E [IgE] antibodies) and subsequent allergic disease. A major new development in this understanding is the recognition that pet exposures consist of not only allergen exposures but also changes in microbial exposures. Exposures to certain pet-associated microbes, especially in the neonatal period, appear to be able to dramatically alter how a child’s immune system develops and this in turn reduces the risk of allergic sensitization and disease. An exciting challenge in the next few years will be to see whether these changes can be developed into a realistic preventative strategy with the expectation of significantly reducing allergic disease, especially asthma.

Deficits in allergy knowledge among physicians at academic medical centers

BACKGROUND

Allergic conditions have high prevalence in the general population. Misconceptions regarding the diagnosis and management of allergic disease among physicians can lead to suboptimal clinical care.

OBJECTIVE

To determine the extent of allergy-related knowledge deficits among physicians.

METHODS

Pediatric and internal medicine resident and attending physicians from 2 separate academic medical centers were asked to answer an anonymous electronic survey. Survey questions addressed 7 different allergy content areas.

RESULTS

Four hundred eight physicians completed surveys (23.9% response rate). Respondents had few correct answers (mean ± SD 1.91 ± 1.43). Pediatric respondents had a larger number of correct answers compared with medicine-trained physicians (P < .001). No individual answered every survey question correctly, and 50 respondents (12.3%) had no correct answer. Three hundred seventy-eight respondents (92.6%) were unable to provide correct answers for at least 50% of survey questions. Level of residency training and prior rotation through an allergy and immunology elective correlated with a larger number of correct responses (P < .01). Only 1 survey question had an overall correct response rate higher than 50% (n = 261, 64%). Correct response rate was lower than 30% for 7 of the 9 possible questions.

CONCLUSION

There are significant knowledge deficits in many areas of allergy-related content among pediatric and internal medicine physicians and across all levels of training and specialty. Given the prevalence of allergic conditions, the potential implications of a negative impact on clinical care are staggering.

Environmental remediation in the treatment of allergy and asthma: latest updates

In the modern era, the prevalence of asthma and allergies are increasing. It has been speculated that environmental exposures are contributing to this rise. Several studies demonstrate that common indoor allergen exposures exacerbate asthma. Minimizing exposure to allergens and remediating the environment play a critical role in the treatment of asthma and allergies. The most effective environmental control measures are tailored multifaceted interventions which include education, thorough cleaning, using high-efficiency particulate air (HEPA) filters, integrated pest management, and maintenance of these practices.