Molecular diagnosis in cat allergy

Abstract

Domestic cats represent one of the most common sources of indoor allergens. All over the world, many households own cats, whose allergens are persistent and widespread. Cat allergy itself is frequent, and its symptoms vary from rhinoconjunctivitis to life-threatening asthma. In vitro diagnosis using precision medicine allergy immunoassays is important because natural cat dander extracts may differ in quality and quantity of some of the individual allergen components and other molecules. In the component-resolved diagnosis of cat allergy, singleplex and multiplex specific immunoglobulin (Ig) E assays include use of the cat-specific major allergen, secretoglobin Fel d 1 (as a species-specific molecule), other allergen components (such as lipocalins Fel d 4, cross-reacting with other animal similar molecules, and Fel d 7, present in small quantities in natural extracts), and serum albumin Fel d 2 (related to the cat-pork syndrome). IgA Fel d 5 and IgM Fel d 6 are not available as allergen components in the current commercial IgE immunoassays, but they may impair the in vitro diagnostic evaluation of cat allergy because galactose-α1,3-galactose is an IgE-binding epitope of these native feline allergens. The benefits of molecular-based cat allergy diagnosis are continually evaluated, as the role of recombinant allergen components already known is detailed and new other molecules of interest may be discovered in the future.

Keywords: Feline; Allergens; Component-resolved diagnosis; Immunoglobulin E; Immunoassays

Core Tip: Cats are a common source of allergens for humans, and allergy to these pets are frequent and variable in their clinical manifestations. The benefits of molecular diagnosis in cat allergy include use of the species-specific major allergen Fel d 1, cross-reacting allergen components, including those present in small quantities in natural extracts, while considering molecules that may impair the in vitro allergy diagnosis. The identification and characterization of molecular cat allergens with clinical significance has allowed their use in singleplex and multiplex immunoglobulin E immunoassays for a precision diagnostic approach.