Background: Cat allergy is a major trigger of asthma world-wide. Molecular patterns of cat sensitization vary between individuals, but their relationship to inflammation in asthmatics has not been extensively studied.
Objective: To investigate the prevalence and levels of IgE antibodies against different cat allergen components and their relationship to type-2 inflammation and total IgE among young asthmatic subjects sensitized to furry animals.
Methods: Patients with asthma (age 10-35 years; n = 266) and IgE sensitization to cat, dog or horse extract (ImmunoCAP), were analysed for IgE to the cat allergen components Fel d 1 (secretoglobin), Fel d 2 (serum albumin), Fel d 4 and Fel d 7 (lipocalins). Independent associations between IgE-antibody concentrations, and fraction of exhaled nitric oxide (FeNO), blood eosinophil (B-Eos) count, and total IgE were analysed by multiple linear regression after adjustment for possible confounders.
Results: The level of IgE against Fel d 2 was independently related to FeNO (P = .012) and total IgE (P < .001), and IgE against Fel d 4 associated with Β-Eos count (P = .009) and total IgE (P < .001). IgE antibodies against Fel d 1 or cat extract did not independently relate to these inflammatory markers (P = .23-.51).
Conclusions: Levels of IgE to lipocalin (Fel d 4) and serum albumin (Fel d 2), but not to secretoglobin (Fel d 1) or cat extract, were independently associated with type-2 biomarkers and total IgE in young asthmatics.
Clinical relevance: We suggest that measurement of IgE to minor cat allergen components may be useful when investigating asthma morbidity in cat allergic subjects.
Keywords: IgE; asthma; clinical immunology; eosinophils; immunologic tests.
© 2018 John Wiley & Sons Ltd.