PREVALENCE OF Fel d 1 CAT ALLERGEN IN HOMES IN SAUDI ARABIA

Aims: Cat allergen levels in settled house dust and their determinants in Saudi Arabia are unknown. The aim of this study was to quantify the levels of the major cat allergen in house dust samples of Saudi homes.

Study Design: Random collection of house dust samples from patients and control homes were quantitatively analyzed for Fel d 1 cat allergen levels using immunoassay techniques.

Place and Duration of Study: The study was carried out in three major cities in Saudi Arabia, viz. Riyadh, Makkah and Jeddah between August 2014 and October 2016.

Methods: A total of 428 house dust samples were randomly collected from allergic patients (n=155) and control homes (n=273). Sieved dust samples were extracted in PBS and, using mAb ELISA, analyzed for Fel d 1 cat allergen. Cat allergen concentration levels were expressed in microgram per gram of dust.

Results: Our results showed that Fel d 1 was present in 86% of homes. The range of values of cat allergen was 0.001-1.938 µg/g dust. Though; the Fel d 1 concentration levels in house dust samples were generally low, clinically significant levels of Fel d 1 (1-8 μg/g dust ) were found in 7% of homes. The majority of homes (both control and patients) with higher levels had no cats in their premises. The levels in Makkah samples (12.7%) were significantly higher compared to Riyadh (4.4%).

Conclusion: The study revealed that a large number of homes, of cat free homes, contained the major allergen Fel d1 and some homes reaching clinical threshold. Therefore, for in vivo and in vitro diagnostic screenings, it is advisable to include cat allergen even if the patients not exposed to cat directly.