Short summary: In this study, a mathematical model for predicting the probability of asthma control based on the FeNO dynamics after 3 months of treatment, the number of cat allergens to which sensitisation is detected and the duration of exposure to a domestic cat after molecular allergy testing was developed.
Summary: The aim of this study was to develop a model for predicting asthma control status in school-aged children, who are sensitised to cat allergens. In this retrospective study, 302 patients were included. Inclusion criteria involved diagnosis of bronchial asthma, age 6-17 years and sensitisation to at least one of the following cat allergens Fel d 1, Fel d 2, Fel d 4, Fel d 7. Patients were selected upon careful history taking, spirometry, skin-prick test with Fel d 1 standardised extract (5,000 BAU / mL), measurement of total IgE and fractional exhaled nitric oxide (FeNO) before and after 3 months of treatment.
To obtain a comprehensive sensitisation profile, serum samples were analysed using the ALEX² test. The following sensitisation prevalences were measured:
• Fel d 1 in 291 (96.36%) children
• Fel d 2 in 18 (5.96%) children
• Fel d 4 in 59 (19.54%) children
• Fel d 7 in 75 (24.83%) children
Combined sensitisations were also observed:
• Fel d 1, Fel d 7 in 32 (10.60%) patients
• Fel d 1, Fel d 4 in 22 (7.28%) patients
• Fel d 1, Fel d 4, Fel d 7 in 22 (7.28%) patients
• Fel d 1, Fel d 2, Fel d 4, Fel d 7 in 12 (3.97%) patients
To evaluate the correlation between controlled asthma and sensitisation to cat allergens, the Searman’s rank correlation coefficient was calculated. A correlation was found between the presence of asthma control and the number of cat allergens to which the child is sensitised, which emphasises the importance of multiple sensitisations. Regarding the structure of sensitisation, a correlation was found between the presence of asthma control and sensitisation to Fel d 4 and Fel d 7. According to the Consensus document on dog and cat allergy, sensitisation to two or more allergens is associated with more severe respiratory symptoms and is a marker of severe asthma.