Usefulness of component resolved analysis of cat allergy in routine clinical practice

Abstract

BackgroundCat allergy is of great importance, and its prevalence is increasing worldwide. Cat allergens and house dust mite allergens represent the major indoor allergens; however, they are ubiquitous. Cat sensitization and allergy are known risk factors for rhinitis, bronchial hyperreactivity and asthma. Thus, the diagnosis of sensitization to cats is important for any allergist.Methods70 patients with positive skin prick tests for cats were retrospectively compared regarding their skin prick test results, as well as their specific immunoglobulin E antibody profiles with regard to their responses to the native cat extract, rFel d 1, nFel d 2 and rFel d 4. 35 patients were allergic to cats, as determined by positive anamnesis and/or nasal provocation with cat allergens, and 35 patients exhibited clinically non-relevant sensitization, as indicated by negative anamnesis and/or a negative nasal allergen challenge.ResultsNative cat extract serology testing detected 100% of patients who were allergic to cats but missed eight patients who showed sensitization in the skin prick test and did not have allergic symptoms. The median values of the skin prick test, as well as those of the specific immunoglobulin E antibodies against the native cat extract, were significantly higher for allergic patients than for patients with clinically non-relevant sensitization. Component based diagnostic testing to rFel d 1 was not as reliable. Sensitization to nFel d 2 and rFel d 4 was seen only in individual patients.ConclusionExtract based diagnostic methods for identifying cat allergy and sensitization, such as the skin prick test and native cat extract serology, remain crucial in routine clinical practice. In our study, component based diagnostic testing could not replace these methods with regard to the detection of sensitization to cats and differentiation between allergy and sensitization without clinical relevance. However, component resolved allergy diagnostic tools have individual implications, and future studies may facilitate a better understanding of its use and subsequently may improve the clinical management of allergic patients.

Characterization of sensitization to furry animal allergen components in an adult population

“…The majority of previous animal component studies have been analysed with multiplex testing using microarray technology (ISAC), which does not have the same degree of resolution as singleplex testing . Only few clinical animal allergy studies have used singleplex testing . The chip‐based technology is less quantitative, which makes the singleplex IgE antibody assays those of choice for routine diagnostic allergy testing .…”

An update on molecular cat allergens: Fel d 1 and what else? Chapter 1: Fel d 1, the major cat allergen

“…Conversely, two new studies analyzing the usefulness of CRD analysis of cat allergy in routine clinical practice drew the exactly opposite conclusion [ 59 , 60 ]. In the first, native cat extract serology testing was 100% successful in detecting patients who were allergic to cats but rFel d 1 testing only 91% [ 59 ]. Thus, 9% of cat allergic patients would have not been detected with CRD testing alone.…”

Diagnosis of Allergy to Mammals and Fish: Cross-Reactive vs. Specific Markers

“…Fel d 1 is regarded as a good marker allergen for a primary sensitization to cat as it is specific for cat and has a high IgE prevalence. Although Fel d 1 is generally recognized by > 90% of cat-allergic patients [ 13 •], there are also reports on patient cohorts in which specific IgE to Fel d 1 have a much lower prevalence [ 52 , 53 ]. However, sensitization to cat components had a stronger prognostic value for new-onset of rhinitis and asthma in comparison to the determination of sensitization to cat extract [ 53 ].…”