Role of nasal challenge and local eosinophilia in indirect exposure to cat in allergic rhinitis patients (original) (raw)
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Clinical & Experimental Allergy, 2007
Background When the clinical history is not conclusive, it may be difficult to make an accurate interpretation of the value of skin tests and serum-specific IgE to cat allergens in asthma cases. Objective To analyse the diagnostic efficiency of skin testing (ST) and serum-specific IgE to cat allergens, based on the results of bronchial-specific challenge with cat epithelium. Methods Sixty-four asthma patients (49 with cat exposure and 15 without) who did not clearly relate their asthma symptoms to cat exposure and had a positive skin prick testing and/ or a positive cat dander-specific IgE determination (CAP-system) underwent intradermal skin tests and specific bronchial challenge with cat epithelium. The results were analysed by receiver operating characteristics curves (ROC curves) and logistic regression. Sensitivity, specificity, positive predictive values and negative predictive values were calculated for different cut-off points. Results Twenty-seven patients (42.2%) had a positive bronchial-specific challenge. The area under the ROC curve for serum-specific IgE quantification is 0.85, which makes a good diagnostic tool out of this test. Intradermal ST predicts the outcome of the bronchoprovocation test better than skin prick testing (area under the ROC curve of 0.74 vs. area under the ROC curve of 0.54, respectively). The logistic regression analysis shows that the estimated probability of a positive bronchial challenge is X93% if CAP values are X17 kU A /L, whereas if CAP values are less than 0.35 kU A /L the estimated probability of a positive bronchial challenge is 16%. When the intradermal skin test is negative, the estimated probability of a positive bronchoprovocation test is 9%, being the test that better identifies patients with a negative bronchoprovocation test.
Sensitization to cat allergen and its association with respiratory allergies: cross-sectional study
Sao Paulo medical journal = Revista paulista de medicina, 2017
Cats are a significant source of allergens that contribute towards worsening of allergic diseases. The aim of this study was to investigate the association between sensitization to cat allergens and allergic respiratory diseases.This was an observational retrospective study based on the skin pricktests results of patients at a tertiary-level hospital in São Paulo. A total of 1,985 test results were assessed. The prevalence of sensitization to cat allergen was 20% (399 patients). Our data indicated that in this population of atopic patients, a positive skin prick test result for cat allergen was not associated significantly with a diagnosis of respiratory allergy.
Cat antigen in homes with and without cats may induce allergic symptoms†
Journal of Allergy and Clinical Immunology, 1996
Although Fel d 1, the major cat allergen, has been found in settled dust samples from homes both with and without cats, the clinical relevance of this allergen has never been studied. In this study we measured airborne concentrations of Fel d 1 in homes both with and without cats and then attempted to relate these levels to those obtained in our experimental cat challenge model to assess their clinical significance. In baseline samples we found measurable levels of airborne Fel d 1 in all 37 homes with cats (range, 1.8 to 578 ng/m3; median, 45.9 ng/m3) and in 10 of the 40 homes without cats (for detectable samples: range, 2.8 to 88.5 ng/m3; median, 17 ng/m3). Fel d 1 was present in the settled dust of 38 of 40 homes without cats (range, 39 to 3750 ng/gm; median, 258 ng/gm), although these levels were only weakly predictive of airborne levels. Repeat samples obtained weekly from 12 homes without cats yielded measurable airborne levels. Fel d 1 in at least one of the four samples from all homes. When compared with challenges performed in our cat room facility at low levels of airborne Fel d 1 (<500 ng/m3), these home levels are within the range capable of causing upper and lower respiratory symptoms in subjects allergic to cats. We therefore conclude that the low level cat exposure that occurs in many homes without cats is capable of inducing symptoms in some patients who are sensitive to cats. The assessment of cat exposure should not be based solely on the presence or absence of a cat in the home.
Annals of Allergy, Asthma & Immunology, 2003
Background: Treatment of cat allergy normally entails removal of the cat from the household, but cat owners are often unwilling to part with their pets, despite clinically relevant allergies. Objective: To determine whether levels of Fel d 1 can be reduced without removal of the cat and whether this will affect symptoms of cat allergy. Methods: Cat-allergic patients underwent randomization to either a group instructed in environmental control (EC) and a group with unchanged environment (UE). Dust samples were obtained and settled Fel d 1 measured by enzyme-linked immunosorbent assay. Patients recorded daily nasal inspiratory flow rates. At baseline, 3 months, and 8 months, patients underwent symptom evaluation. Results: Eighteen patients were randomized to the EC group and 22 to the UE group; the final number completing the study was 31, 15 in the EC group, and 16 in the UE group. At 8 months, home Fel d 1 levels had diminished to 6.8% of baseline levels in the EC group, whereas no reduction in levels was noted in the UE group. In the EC group, significant improvements were found in nasal inspiratory flow rate and symptoms compared with the UE group. Patients did not have difficulties adhering to EC measures. Conclusion: A decrease in the allergen load was found in the EC group, which had a significant effect on symptoms of nasal allergy.
American Journal of Rhinology & Allergy, 2012
Background: There is conflicting evidence whether nasal nitric oxide (NO) is associated with current rhinitis and with other possible predictors. Most studies have been performed in clinical cohorts and there is a lack of studies based on a general population sample. The aim of the present study was to investigate predictors for levels of nasal nitric oxide (NO) in a general population. Methods: The population consisted of 357 subjects from Gothenburg participating in the follow-up of the European Respiratory Health Survey in 1999-2001. All subjects completed an extensive respiratory questionnaire. Nasal NO was measured from one nostril at a time with a sampling rate of 50 mL/s for 16 seconds and the nasal NO concentration was determined as the mean value within the plateau phase. Mattress dust samples were collected for cats and mites in a subsample of subjects. Ambient and exhaled NO was also measured. The predictors for nasal NO were analyzed in multiple linear regression models. Results: There was no relation between the levels of nasal NO and reporting current rhinitis. Nasal NO was significantly increased among those with high levels of IgE against cats and current smokers had significantly lower nasal NO. There was also a positive association between ambient NO and nasal NO. There were no significant associations between nasal NO and sex, age, or height, or between nasal NO and measured levels of cat antigen. Conclusion: In this general population sample we found no relation between current rhinitis and nasal NO levels. There was a clear association between sensitization to cat and nasal NO, but there was no relation to current exposure to cat allergen. Our data support that nasal NO has a limited value in monitoring upper airway inflammation.
Bronchial Responsiveness in Atopic Adults Increases with Exposure to Cat Allergen
American Journal of Respiratory and Critical Care Medicine, 2007
Rationale: The association of asthma with sensitization and allergen exposure is known to be complex. There have been few studies of bronchial responsiveness in relation to both risk factors in adults. Objectives: To determine the relation of bronchial responsiveness to allergen exposure and IgE sensitization in a community study taking into account the major determinants of bronchial responsiveness in adulthood. Methods: Cross-sectional data were drawn from 1,884 participants in 20 centers in the European Community Respiratory Health Survey follow-up, which included measurement of house dust mite and cat allergen in mattress dust samples, and IgE sensitization to four allergens. Bronchial responsiveness to methacholine was expressed as a continuous variable, and analyzed by multiple regression. Measurements and Main Results: The trend toward greater bronchial responsiveness with increasing exposure to cat allergen was greater in those sensitized to any of the four allergens than those not sensitized (p ϭ 0.001); there was no significant interaction between cat sensitization and Fel d 1 exposure. No trend was found with house dust mite allergen exposure. The difference in bronchial responsiveness between those exposed to the highest levels compared with the lowest was approximately ؊2.02 doubling doses of PD 20 (95% confidence interval, ؊3.06 to ؊0.97), and nearly as great in those exposed to more moderate levels. Conclusions: Cat allergen exposure at moderate levels may be harmful to all atopic adults. The clinical implication is that it is insufficient to test patients with asthma for cat sensitization; all atopic individuals may benefit from reduced cat exposure.
Journal of Allergy and Clinical Immunology, 1997
Background: Why allergic subjects may have asthma or rhinitis on allergen exposure remains unclear. Objective: This study was carried out to compare airway responses during environmental allergen challenge (EAC) with quantitative allerge n provocation challenges of the upper and lower airways. Methods: Thirteen subjects with allergy to cats underwent EAC to cats. Lower airway responses during EAC were compared with bronchoprovocation with allergen. Nasal mucosal challenge with allergen-soaked disks were compared with EAC nasal responses. Nonspecific bronchial reactivity was assessed with methacholine: allergen sensitivity was assessed by skin prick tests. RAST. and end-point skin titration. Results: During EAC, the maximal fall in FEV 1 ranged from 6% to 57% (median, 18%) and correlated closely with allergen bronchoprovocation PD2o (Spearman's correlation coefficient [Rs] =-0.85, p < 0.0002). EAC asthmatic responses and allergen bronchoprovocation correlated with methacholine PD2o (R s =-0.85, p = 0.0002 and Rs = 0.83, p = 0.0004, respectively). Nasal provocation and EAC nasal responses correlated with each other but not with lower airway responses. On the basis of EAC and allergen bronchoprovocation responses, seven participants with asthma were identified. This group was significantly more sensitive to inhaled methacholine but was similar to the nonasthmatic group in IgE-mediated sensitivity and nasal responses. Conclusions: The lower respiratory tract is less responsive to allergic and nonallergic stimuli in persons with allergic rhinitis. In persons with asthma during EAC, the response to nebulized cat allergen is also abnormal and correlates closely with their abnormal responsiveness to nonimmunologic stimuli. (
Study of Cat Allergy Using Controlled Methodology—A Review of the Literature and a Call to Action
Frontiers in Allergy, 2022
The prevalence of cat allergen-induced AR is increasing worldwide, prompting its study using controlled methodology. Three general categories of allergen exposure models currently exist for the study of cat allergen-induced AR: natural exposure cat rooms, allergen exposure chambers (AEC), and nasal allergen challenges (NAC). We evaluated existing literature surrounding the use of these models to study cat allergen induced AR using online research databases, including OVID Medline, Embase, and Web of Science. We report that natural exposure cat rooms have been important in establishing the foundation for our understanding of cat allergen-induced AR. Major limitations, including variable allergen ranges and differing study designs highlight the need for a more standardized protocol. In comparison, AECs are an exceptional model to mimic real-world allergen exposure and study long-term implications of AR with large sample sizes. Existing AECs are limited by heterogeneous facility design...