Mast Cell Test Shows Promise for Identifying Cat Allergy

A SERUM-BASED mast cell activation test could help identify which people sensitised to cats develop clinically relevant airway responses, a small study suggests. 

The findings offer a potential way to distinguish a positive allergy test from sensitisation that contributes to asthma symptoms, although larger prospective studies are needed before the approach can guide routine care. 

Moving Beyond Sensitisation 

Positive skin prick tests and cat-specific immunoglobulin E (IgE) measurements demonstrate sensitisation, but do not establish that cat exposure causes respiratory symptoms. This distinction matters when advising patients about reducing exposure or removing a pet from the home. 

Researchers in Manchester, UK, and Hamilton, Canada, investigated whether functional cell testing could provide additional information. They first compared conventional basophil activation testing, progenitor-derived basophil testing and mast cell activation testing (MAT) in 17 cat-sensitised and 10 non-sensitised participants. 

For MAT, cells were sensitised with participants’ serum before exposure to different cat allergen concentrations. Unlike conventional basophil testing, this approach permits batch testing of stored samples. 

Responses Linked to Airway Reactivity 

All three assays distinguished sensitised from non-sensitised participants under optimal conditions. However, the two serum-based approaches maintained strong discrimination across all tested dilutions, and MAT was selected for further analysis. 

Among 18 cat-sensitised participants who underwent inhaled cat allergen challenge, MAT responses correlated strongly with the early asthmatic response (r=0.82; p<0.001). An exploratory analysis also identified a correlation with the late response (r=0.62; p=0.006). 

A separate group of 10 sensitised participants had negative methacholine challenge results and did not undergo inhaled allergen challenge. Within this group, the four reporting cat-induced asthma-like symptoms had higher MAT responses than the six without these symptoms. 

Further Validation Needed 

MAT also correlated strongly with cat-specific IgE, but participants with similar IgE concentrations could show markedly different cellular responses. This suggests that the two measurements capture related, rather than interchangeable, information. 

An exploratory elevated-response group more frequently reported symptoms than a low-response group, but this difference did not reach statistical significance. 

The authors describe the findings as proof of concept. Small cohorts, potentially inaccurate symptom reporting and missing cat-specific IgE measurements in Canadian participants limited comparisons. Crucially, the study did not establish that MAT outperforms conventional testing for predicting clinical allergy. 

Prospective studies measuring MAT, specific IgE and airway responses in the same participants are needed to establish its additional diagnostic value and assess whether the approach extends to other inhaled allergens. 

Reference  

Wu J et al. Functional Mast Cell Testing Identifies Clinically Relevant Cat Sensitisation. Clin Exp Allergy. 2026:1–3. https://doi.org/10.1111/cea.70461