Cat Allergen Exposure Research Articles

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.

Impact of Direct and Indirect Cat Allergen Exposure Patterns on Allergic Rhinitis and Asthma in Cat-Sensitized Patients

Impact of Direct and Indirect Cat Allergen Exposure Patterns on Allergic Rhinitis and Asthma in Cat-Sensitized Patients

Reproducibility of the Specialized PArticulate Control Environmental Exposure Unit (SPAC-EEU) as a Novel Controlled Cat Dander Exposure Room

Allergic rhinitis (AR) induced by cat allergens, most commonly to Felis domesticus allergen 1 (Fel d 1), is estimated to affect 10-20% of the world’s population. Accurate and reproducible clinical models of prolonged cat allergen exposure are limited. Using our Specialized PArticulate Control Environmental Exposure Unit (SPAC-EEU), we sought to assess the capacity of our equipment to accurately and reproducibly distribute cat allergen.

Development of a Mobile Naturalistic Exposure Chamber for Cat Dander

Cat allergen exposure chambers support clinical research through controlled exposure. Permanent chambers with live cats (e.g., the RMT Naturalistic Exposure Chamber) exist, but expansion to multi-site clinical trials is inhibited by the expense of operating brick-and-mortar facilities with animals. We have developed a portable model for controlled exposure to natural cat allergen to facilitate multi-site clinical trials.

Featured Cover

Clinical & Experimental AllergyVolume 52, Issue 2 p. i-i FEATURED COVERFree Access Featured Cover First published: 28 January 2022 https://doi.org/10.1111/cea.14097AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract The cover image is based on the Research Article Cat allergen exposure in a naturalistic exposure chamber: A prospective observational study in cat-allergic subjects by Meagan O’Brien et al., https://doi.org/10.1111/cea.14087. Volume52, Issue2February 2022Pages i-i RelatedInformation

Cat allergen exposure in a naturalistic exposure chamber: Aprospective observational study in cat-allergic subjects.

BackgroundTo determine the proportion and reproducibility of cat‐allergic mild asthmatics with early asthmatic response (EAR) during cat allergen exposure in a naturalistic exposure chamber (NEC).MethodsThis was a prospective, observational study in 30 cat‐allergic mild asthmatics who received two 180‐min cat‐allergen (Felis domesticus allergen 1 [Fel d 1]) challenges 27 days apart in an NEC.ResultsAn EAR (≥20% reduction from baseline in forced expiratory volume in 1 s [FEV1]) was observed in 67% and 52% of subjects at first and second NEC exposure, respectively, with similar median time to EAR; 44% of subjects had an EAR on days 1 and 28. Late asthmatic response (≥15% reduction in FEV1 within 24 h of NEC exit) was observed in 33% of subjects following either exposure. Average FEV1 and total nasal symptom score during NEC exposure were highly correlated within subjects between NEC exposures (r = 0.91, p < 0.0001; r = 0.73, p < 0.001), but total ocular symptom score was not. Time to EAR, but not average FEV1, was significantly associated with NEC Fel d 1 concentration, which was variable. There were no serious adverse events; 12/30 subjects experienced 20 adverse events (including asthma, 10%; headache, 10%).ConclusionsThe NEC model demonstrates that average FEV1 change is highly reproducible and has a low correlation with cat allergen levels. However, time to EAR and incidence of EAR are less reproducible and are highly correlated with NEC allergen levels. Average FEV1, rather than incidence of EAR or time to EAR, could be considered as an endpoint for interventional trials testing cat‐specific anti‐allergy therapies using an NEC.

Associations between Environmental dust composition and Atopic Dermatitis in urban and rural settings.

Environmental exposures are involved in the pathogenesis of the allergic phenotype and in determining which individual triggers a person becomes sensitized to. Atopic dermatitis (AD) may modulate these effects through increased penetration through the skin modifying the immune system and AD may be triggered or intensified by environmental exposures. These exposures and immune-modulating factors may differ in urban and rural environments. To compare house dust composition in urban and rural settings and correlate them with AD outcomes. Dust samples were collected from the beds of 156 children aged 6months to 3years. 42% of participants had atopic dermatitis. Samples were analyzed for bacterial endotoxin, fungal (β-1,3-glucan) levels, and house dust mite, cockroach, dog, cat, mouse, and peanut allergen. Exposures were compared in urban and rural environments and in participants with and without AD. Endotoxin but not fungal β-glucan exposure is higher in the environment of healthy controls than children with AD in both urban and rural settings. House dust mite allergen exposure is high in urban and rural settings with Dermatophagoides detected in 100% of samples. Cat and dog allergen exposure mirrors pet ownership patterns which differ slightly between groups and environments. Mouse allergen exposure is higher in urban homes. Environmental endotoxin may be protective against AD in both urban and rural settings. There are marked differences in allergen exposure in urban and rural settings, but these are unlikely to be important protective or risk factors.

P207 REPRODUCIBILITY OF THE EARLY ASTHMATIC RESPONSE AMONG CAT-ALLERGIC MILD ASTHMATICS IN A NATURALISTIC EXPOSURE CHAMBER

We evaluated the proportion of cat-allergic mild asthmatics who experience an early asthmatic response (EAR) during cat allergen exposure in a Naturalistic Exposure Chamber (NEC) and the reproducibility of the EAR.

Does Air Filtration Work for Cat Allergen Exposure?

The goal of this review is to compress all important information and results of the research in reducing cat allergen exposure using air filtration. Fel d 1 is the major allergen responsible for IgE responses in 90 to 95% of patients with cat allergy. Reduction of cat allergen in indoor air with different air filtration systems and portable devices has been demonstrated in the majority of the studies. Recently, early and late asthmatic responses were significantly reduced using portable HEPA air cleaners in an environmental exposure chamber. This review provides a comprehensive overview of the current state of airborne Fel d 1 air filtration targeting the most efficient devices in cat allergen reduction. Novel emerging HEPA filters are targeting reduction of cat indoor asthma trigger so patient can might benefit from efficient solution.

Efficacy of air cleaners in asthmatics allergic to cat in ALYATEC® environmental exposure chamber.

Air cleaners have been promoted for respiratory allergic disease prevention, but there is no clear clinical proof of their efficacy in allergic asthma. To examine the efficacy of a new air cleaner on early and late asthmatic responses in cat-allergic patients. This randomized, cross-over, double-blind placebo-controlled study enrolled 24 cat-asthmatic patients with GINA 1 asthma. At baseline, participants were exposed to 40ng/m3 of airborne cat allergen for a maximum of 2hours in ALYATEC® environmental exposure chamber(EEC). All participants were subsequently randomized into two groups that were exposed to cat allergen, either with active then placebo air cleaners or with placebo then active air cleaners with a 3-week interval in the EEC. This study was registered under number (NCT03928561). Fewer patients experienced an EAR with active air cleaners (seven patients; 29.17%) than placebo (21 patients; 87.50%). The response incidence was lower with active than with placebo air cleaners. A Cox model demonstrated a significant treatment effect (hazard ratio, 0.10; P=.002). Active air cleaners also prevented late asthmatic response: four patients (16.67%) had a late asthmatic response with active air cleaners compared to 11 patients (45.83%) with placebo (Prescott test P=.002). Active air cleaners also decreased the maximal severity of bronchial response (FEV1 decrease of 17.24% with active vs 25.62% with placebo air cleaners; P=.001). Our present results demonstrated that Intense Pure Air XL® air cleaners significantly prevented early and late asthmatic responses among cat-allergic asthmatics during cat allergen exposure in the ALYATEC® EEC.

Sampling Devices for Indoor Allergen Exposure: Pros and Cons.

To review current indoor allergen sampling devices, including devices to measure allergen in reservoir and airborne dust, and personal sampling devices, with attention to sampling rationale and major indoor allergen size and characteristics. While reservoir dust vacuuming samples and airborne dust volumetric air sampling remain popular techniques, recent literature describes sampling using furnace filters and ion-charging devices, both which help to eliminate the need for trained staff; however, variable correlation with reservoir dust and volumetric air sampling has been described. Personal sampling devices include intra-nasal samples and personal volumetric air samples. While these devices may offer better estimates of breathable allergens, they are worn for short periods of time and can be cumbersome. Reservoir dust sampling is inexpensive and is possible for families to perform. Airborne dust sampling can be more expensive and may better quantify cat, dog, and mouse allergen exposure. Personal sampling devices may offer a better representation of breathable air.

Stabilizing Fel d1 Levels in a Cat Allergen Exposure Chamber

Naturalistic exposure to cat allergen in a controlled environment is optimal for assessing patient responses. However, maintaining control of Feld1 levels remain problematic as reported values can vary significantly within and between chambers. This study aims to assess new and previous methods to aerosolize Feld1 in our Natural Exposure Chamber. The best method for maintaining dander levels will be utilized for future cat allergen exposure studies. The chamber, volume 14.7 m3 was designed and built to accommodate two neutered cats and 1-2 subjects. Samples were obtained at 3 locations in the chamber using portable air samplers (Gillian 5000) with glass fiber filters (Millipore), flow rate 4 L/min. Feld1 was quantified using ELISA (Indoor Biotechnologies). Over 20 weeks, 30-minute air samples and floor and wall swabs were collected to measure Feld1. Fans and blanket shaking were evaluated as means to aerosolize dander. With no disturbance, air Feld1 levels were mostly below the limit of detection in the 20 weeks following the cats’ introduction to the room. Over the same time, wall (1.7 to 19.2 ng/m2) and floor Feld1 (15.1 to 138.2 ng/m2) increased. Fans placed 1.5 and 7 feet above the floor aerosolized Feld1 (12.6 ± 19.8 and 9.17 ± 6.1 ng/m3, respectively). Shaking the cats’ blankets generated 45.9 ± 60.1 ng/m3 in the air and shaking every 15 minutes 111.7 ± 46.3 ng/m3. Feld1 increased on walls and floor over 20 weeks of cat residence but required intervention for aerosolization. Blanket shaking generated higher levels of Feld1 in the air.

Cat ownership, cat allergen exposure, and trajectories of sensitization and asthma throughout childhood

Summary Exposure to cat and/or cat allergens can confer either an increase in risk, or protection, or will have no effect, depending on the age of the assessment, study design and the choice of study population.

Sensitization and Exposure to Pets: The Effect on Asthma Morbidity in the US Population

Although pets are found in more than 50% of US homes, the effect of petallergen exposure on asthma morbidity in the US population is not well documented. To determine the effect of dog and cat allergen exposures on asthma morbidity in the US population. The National Health and Nutrition Examination Survey is a representative sample of civilian US population. Data on asthma, dog and cat allergen levels in bedroom dust, as well as specific IgE to dog and cat were analyzed for all participants 6years or older. Pets are common in the United States, with more that 50% of households having a dog or a cat or both. The prevalence of allergic sensitization in the National Health and Nutrition Examination Survey population was similar for dog and cat, with both being approximately 12%. Among those who were sensitized, exposure to elevated levels of petallergens was associated with an increased prevalence of asthma and asthma attacks. Indeed, 44.2% of the asthma attacks were attributable to exposure to high levels of dog allergen in the bedroom among patients with asthma sensitive to dog and 30.3% were attributable to cat allergen exposure among the comparable cat-sensitive and exposed group. Projecting these results to the US population indicates more than 1 million increased asthma attacks each year for the dog-sensitive and exposed group and more than 500,000 increased asthma attacks for the cat-sensitive and exposed population of patients with asthma. Exposure to elevated levels of dog and cat allergens among those sensitized individuals with asthma is associated with excess asthma attacks. Reducing petallergen exposures has the potential for a significant decrease in asthma morbidity.

Chronic cat allergen exposure induces a TH2 cell–dependent IgG4 response related to low sensitization

In human subjects, allergen tolerance has been observed after high-dose allergen exposure or after completed allergen immunotherapy, which is related to the accumulation of anti-inflammatory IgG4. However, the specific T-cell response that leads to IgG4 induction during chronic allergen exposure remains poorly understood. We sought to evaluate the relationship between cat allergen-specific T-cell frequency, cat allergen-specific IgE and IgG4 titers, and clinical status in adults with cat allergy with and without cat ownership and the cellular mechanism by which IgG4 is produced. Fel d 1-, Fel d 4-, Fel d 7-, and Fel d 8-specific T-cell responses were characterized by CD154 expression after antigen stimulation. In allergic subjects without cat ownership, the frequency of cat allergen (Fel d 1 and Fel d 4)-specific TH2 (sTH2) cells correlates with higher IgE levels and is linked to asthma. Paradoxically, we observed that subjects with cat allergy and chronic cat exposure maintain a high frequency of sTH2 cells, which correlates with higher IgG4 levels and low sensitization. B cells from allergic, but not nonallergic subjects, are able to produce IgG4 after cognate interactions with sTH2 clones and Fel d 1 peptide or the Fel d 1 recombinant protein. These experiments suggest that (1) allergen-experienced B cells with the capacity to produce IgG4 are present in allergic subjects and (2) cat allergen exposure induces an IgG4 response in a TH2 cell-dependent manner. Thus IgG4 accumulation could be mediated by chronic activation of the TH2 response, which in turn drives desensitization.

Is there a threshold concentration of cat allergen exposure on respiratory symptoms in adults?

Background and ObjectiveCat allergen concentrations higher than 8 μg/g in settled house dust, have been suggested to provoke exacerbation of allergic respiratory symptoms. However, whether the 8μg/g of indoor cat allergen concentration is indeed the minimal exposure required for triggering the asthma related respiratory symptoms or the development of sensitization has not yet been confirmed. We studied the associations between domestic cat allergen concentrations and allergic symptoms in the European Community Respiratory Health Survey II, with the aim of confirming this suggested threshold.MethodsCat allergen concentrations were measured in the mattress dust of 3003 participants from 22 study centres. Levels of specific immunoglobulin E to cat allergens were measured in serum samples using an immunoassay. Information on allergic symptoms, medication use, home environment and smoking was obtained from a face-to-face interview.ResultsDomestic cat allergen concentrations were not associated with allergic/ asthmatic symptoms in the entire study population, nor in the subset sensitized to cat allergen. We also found no association among individuals exposed to concentrations higher than 8 μg/g. However, exposure to medium cat allergen concentrations (0.24-0.63 μg/g) was positively associated with reported asthmatic respiratory symptoms in subjects who have experienced allergic symptoms when near animals.ConclusionsThe proposed 8 μg/g threshold of cat allergen concentrations for the exacerbation of allergic/ respiratory symptoms was not confirmed in a general European adult population. Potential biases attributable to avoidance behaviours and an imprecise exposure assessment cannot be excluded.

Association between allergic sensitization and exhaled nitric oxide in children in the School Inner-City Asthma Study

Association between allergic sensitization and exhaled nitric oxide in children in the School Inner-City Asthma Study

Effect of a novel temperature-controlled laminar airflow device on personal breathing zone aeroallergen exposure.

Temperature-controlled laminar airflow improves symptoms in atopic asthmatics, but its effects on personal allergen exposure are unknown. We aimed to evaluate its effects on personal cat allergen and particulate exposures in a simulated bedroom environment. Five healthy volunteers lay under an active and an inactive temperature-controlled laminar airflow device for 175min, in a simulated bedroom containing bedding from a cat owner. Total airborne particles (≥0.5 - ≥10μm diameter) were quantified with a laser particle counter. Airborne allergen was sampled with Institute of Occupational Medicine filters. Inhaled exposure was sampled with nasal air samplers. Allergen-containing particles were quantified by immunoassay. Treatment reduced total airborne particles (>0.5μm diameter) by >99% (P<0.001) and reduced airborne allergen concentration within the breathing zone (ratio of median counts=30, P=0.043). Treatment reduced inhaled allergen (ratio of median counts=7, P=0.043). Treatment was not associated with a change in airborne allergen concentration outside of the breathing zone (P=0.160). Temperature-controlled laminar airflow treatment of individuals in an allergen-rich experimental environment results in significant reductions in breathing zone allergenic and non-allergenic particle exposure, and in inhaled cat allergen exposure. These findings may explain the clinical benefits of temperature-controlled laminar airflow.

Neither Dust Mite nor Cat Allergen Exposure Is Associated with Lung Function or Asthma Morbidity in Sensitized Baltimore City Children

RationaleAlthough pest allergen exposures are associated with asthma morbidity in sensitized Baltimore City children, the effects of dust mite (DM) and cat allergen (Ct) exposures on asthma in this population are unclear.Methods144 children (5-17y) with asthma were skin prick tested (SPT) at baseline. Lung function, health care utilization data, and bedroom dust samples were collected at baseline, 3, 6, 9, and 12 months. Der f 1 and Fel d 1 content in dust samples was quantified by ELISA. +SPT was defined as a net wheal >3mm. Exposure was defined as bedroom DM>2 μg/g and bedroom Ct> 8 μg/g. Analyses were adjusted for age, gender, type of insurance, total IgE, and sensitization and exposure to mouse and cockroach.ResultsParticipants were predominantly African American (91%), had public health insurance (85%), and had ≥1 +SPT (90%). FEV1/FVC% did not significantly differ between cat sensitized and exposed (S+E+) and non-cat-sensitized or non-cat-exposed (S-E-) participants (predicted% [95% CI]: (81.3[78.8-83.7]) and 80.7[79.4-82.0], respectively; p=0.6). This was also true for DM (S+E+: 81.8[78.8-84.8]; S-E-: 80.8[79.5-82.1], p=0.5). Acute asthma visits were similar for the Ct S+E+ and Ct S-E- groups (OR[95%CI]: 1.13[0.61-2.12]). The same trend held for DM S+E+ vs DM S-E- participants (0.41[0.16-1.03]). These findings were similar across various exposure cutpoints and with or without adjustment for pest allergen exposure and sensitization.ConclusionsDM and Ct allergen exposures are not major contributors to asthma morbidity in Baltimore City children. Public health initiatives in Baltimore should focus on pest allergens, which are known to contribute to asthma morbidity. RationaleAlthough pest allergen exposures are associated with asthma morbidity in sensitized Baltimore City children, the effects of dust mite (DM) and cat allergen (Ct) exposures on asthma in this population are unclear. Although pest allergen exposures are associated with asthma morbidity in sensitized Baltimore City children, the effects of dust mite (DM) and cat allergen (Ct) exposures on asthma in this population are unclear. Methods144 children (5-17y) with asthma were skin prick tested (SPT) at baseline. Lung function, health care utilization data, and bedroom dust samples were collected at baseline, 3, 6, 9, and 12 months. Der f 1 and Fel d 1 content in dust samples was quantified by ELISA. +SPT was defined as a net wheal >3mm. Exposure was defined as bedroom DM>2 μg/g and bedroom Ct> 8 μg/g. Analyses were adjusted for age, gender, type of insurance, total IgE, and sensitization and exposure to mouse and cockroach. 144 children (5-17y) with asthma were skin prick tested (SPT) at baseline. Lung function, health care utilization data, and bedroom dust samples were collected at baseline, 3, 6, 9, and 12 months. Der f 1 and Fel d 1 content in dust samples was quantified by ELISA. +SPT was defined as a net wheal >3mm. Exposure was defined as bedroom DM>2 μg/g and bedroom Ct> 8 μg/g. Analyses were adjusted for age, gender, type of insurance, total IgE, and sensitization and exposure to mouse and cockroach. ResultsParticipants were predominantly African American (91%), had public health insurance (85%), and had ≥1 +SPT (90%). FEV1/FVC% did not significantly differ between cat sensitized and exposed (S+E+) and non-cat-sensitized or non-cat-exposed (S-E-) participants (predicted% [95% CI]: (81.3[78.8-83.7]) and 80.7[79.4-82.0], respectively; p=0.6). This was also true for DM (S+E+: 81.8[78.8-84.8]; S-E-: 80.8[79.5-82.1], p=0.5). Acute asthma visits were similar for the Ct S+E+ and Ct S-E- groups (OR[95%CI]: 1.13[0.61-2.12]). The same trend held for DM S+E+ vs DM S-E- participants (0.41[0.16-1.03]). These findings were similar across various exposure cutpoints and with or without adjustment for pest allergen exposure and sensitization. Participants were predominantly African American (91%), had public health insurance (85%), and had ≥1 +SPT (90%). FEV1/FVC% did not significantly differ between cat sensitized and exposed (S+E+) and non-cat-sensitized or non-cat-exposed (S-E-) participants (predicted% [95% CI]: (81.3[78.8-83.7]) and 80.7[79.4-82.0], respectively; p=0.6). This was also true for DM (S+E+: 81.8[78.8-84.8]; S-E-: 80.8[79.5-82.1], p=0.5). Acute asthma visits were similar for the Ct S+E+ and Ct S-E- groups (OR[95%CI]: 1.13[0.61-2.12]). The same trend held for DM S+E+ vs DM S-E- participants (0.41[0.16-1.03]). These findings were similar across various exposure cutpoints and with or without adjustment for pest allergen exposure and sensitization. ConclusionsDM and Ct allergen exposures are not major contributors to asthma morbidity in Baltimore City children. Public health initiatives in Baltimore should focus on pest allergens, which are known to contribute to asthma morbidity. DM and Ct allergen exposures are not major contributors to asthma morbidity in Baltimore City children. Public health initiatives in Baltimore should focus on pest allergens, which are known to contribute to asthma morbidity.

The increase in exhaled NO following allergen challenge is not associated with airway acidification

Exhaled nitric oxide (NO), commonly accepted marker of airways inflammation, may be generated both by specific enzymes, NO synthases, as well as by nonenzymatic reduction in its metabolites. During asthma exacerbations, owing to lower airways pH, it has been reported that nitrite reduction may contribute to the increase in exhaled NO. Allergen exposure, an important cause of asthma exacerbations, is also known to increase exhaled NO. To investigate whether cat allergen exposure of cat-sensitized asthmatics leads to airway acidification, which could explain the expected increase in exhaled NO. Twelve nonsmoking, cat-sensitized patients (nine women) aged 33·5 (22-54) years with mild intermittent asthma performed a cat allergen challenge. Exhaled NO at 50-200 mL s(-1), nasal NO, exhaled breath condensate (EBC) pH, nitrite and nitrate were measured before, 8 and 24 h after allergen challenge. A significant increase in FE(NO 50) was observed 24 h after allergen challenge compared to baseline: 110 ppb (34, 143) vs. 60 ppb (19, 122), P = 0·006. This was mainly explained by an increase in bronchial NO flux (P = 0·02), while no changes in EBC pH were observed (P = 0·35). Allergen exposure is not associated with airways acidification, implying that the observed increase in exhaled NO is probably because of enzymatic NO production.