# Pollen-Food Allergy Syndrome: Allergens, Clinical Insights, Diagnostic and Therapeutic Challenges
## 7 PFAS Diagnosis
### Basophil Activation Test (BAT)
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**Heading** & **ImmunoCAP** & **ISAC (Immuno Solid-Phase Allergen Chip; ThermoFisher Scientific, Waltham, MA, USA)** & **ALEX (Allergy Xplorer)** \\ \hline
**How It Works** & Singleplex assay that measures IgE to one allergen or component per test. & Multiplex assay testing IgE to \(>\) 100 allergen components on a microarray chip. & Multiplex assay testing IgE to \(>\) 300 whole allergens and molecular components on an allergen array. \\ \hline  & Uses a solid-phase system with allergens immobilized on a cellulose sponge matrix. & Uses purified allergens immobilized on a chip, requiring minimal serum (20-30 \(\mu\)L). & Integrates whole extracts and components with cross-reactivity inhibition for higher specificity. \\ \hline  & Results are quantitative (kU/L). & Results are semi-quantitative (fluorescence intensity levels). & Results are semi-quantitative and integrate cross-reactivity adjustments. \\ \hline
**Advantages** & Provides precise measurements of IgE levels, helping assess sensitization and risk. & Semi-quantitative results allow broad allergen screening and cross-reactivity insights. & Semi-quantitative results combined with inhibition testing improve specificity for genuine sensitization. \\ \hline _Comprehensive testing_ & Wide library of allergens, including region-specific ones. & Simultaneous testing for \(>\) 100 allergen components across polilers, foods, and other sources. & Tests \(>\) 300 allergens, covering both whole extracts and components for comprehensive profiling. \\ \hline _Sensitivity and specificity_ & High sensitivity and specificity targeted allergens for targeted allergens. & Ideal for identifying cross-reactivity due to parallelness like PR-10, profiling, and LITs. & High specificity through cross-reactivity inhibition technology. \\ \hline _Ease of use_ & Widely available, standardized, and reproducible across labs. & Requires minimal serum and provides a complete sensitization overview. & User-friendly data presentation with clear insights into primary and cross-reactive organizations. \\ \hline \hline
**Limitations** & & & \\ \hline _Cost_ & Can be expensive for multiple allergens or components. & Expensive but cost-effective for complex allergy cases. & Relatively expensive but efficient for patients with complex or multiple suspected alleges. \\ \hline _Result format_ & Quantitative results are easy to interpret. & Semi-quantitative results require experienced interpretation to correlate with clinical relevance. & Semi-quantitative results may lack the precision needed for exact risk assessment. \\ \hline _Component limitations_ & Limited to clinician-selected allergens or components; rare ones may be unavailable. & Does not include all region-specific allergens, limiting coverage in some cases. & Some are or region-specific allergens may be absent. \\ \hline _Serum requirement_ & Requires a larger volume of serum for testing multiple allergens. & Requires minimal serum (20-30 \(\mu\)L). & Requires a low volume of serum (100 \(\mu\)L). \\ \hline Applications in PFAS & & & \\ \hline _Identifying parallelegers_ & Effective for targeted testing of parallelegers like PR-10 proteins, profilms, and LITs. & Simultaneously identifies sensitization to multiple parallelegers like PR-10 proteins, profilms, and LITs. & Covers a wide range of panalergens, integrating whole extracts and components for detailed insights. \\ \hline _Primary vs. cross-reactivity_ & Differentiates primary food alleles from cross-reactivity with pollens. & Broad allergen panel helps identify patterns of cross-reactivity across multiple allergens sources. & Combines whole extracts and components to distinguish primary sensitization from cross-reactivity. \\ \hline _Risk stratification_ & Quantitative results enable detailed risk assessment (e.g., _Arn h 2_ for severe peanut allergy). & Helps determine risk based on allergen stability (e.g., PR-10 for mild symptoms, LITs for systemic reactions). & Identifies risk by combining sensitization profiles with cross-reactivity inhibition for stability \\ \hline _Guilding dietary advice_ & Ideal for providing specific advice based on IgE levels to individual allergens. & Identifies parallelegen sensitization, enabling tailored dietary recommendations (e.g., raw vs. cooked tolerance). & Integrates sensitization profiles to guide personalized dietary and exposure advice. \\ \hline _Supporting immunotherapy_ & Identifies primary allergens for allergen immunotherapy (e.g., _Ret v 1_ for birch). & Helps guide allergen immunotherapy decisions by clarifying primary sensitization patterns. & Assists in AIT decisions by revealing sensitization to multiple relevant allegers. \\ \hline \multicolumn{2}{p{113.8 pt}}{**Insights/Observations**} & & & \\ \hline _Special use cases_ & Ideal for monitoring sensitization over time or tracking therapy response. & Best for initial screening of complex cases or polysensitization. & Excellent for broad sensitization profiling in patients with multiple or unclear triggers. \\ \hline _Comparative edge_ & Best for precise, targeted testing and long-term tracking of IgE levels. & Ideal for comprehensive overviews in patients with complex allergic profiles. & Combines extract- and component-based testing with cross-reactivity inhibition for higher specificity. \\ \hline \hline \end{tabular}
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