Clinical utility of immunological methods based on the singleplex and multiplex ImmunoCap systems for diagnosis of shrimp allergy

Extended IgE profile of shrimp-sensitized patients based on Multiplex Examination ALEX2 - Allergy Explorer

Introduction

The key to the correct diagnosis of shrimp allergy is a qualification to the most efficient diagnostic method and later interpretation of the result. To achieve this, it is necessary to apply a diagnostic strategy relevant to each patient's clinical situation and approach every case individually.

Aim

In this study the allergen profile of shrimp-sensitized patients was analysed using ALEX2 Allergy Explorer.

Material and methods

This study includes 50 adult patients with positive prick-by-prick tests with tiger shrimp bought from the local eco-market and an elevated concentration of IgE specific to the shrimp allergen extract (ImmunoCap). A total of 35 patients with negative skin prick tests with shrimp and not detectable sIgE shrimp in ImmunoCap were included in the control group. All patients had ALEX2 Allergy Explorer microarray test.

Results

In the shrimp-sensitized group, 22 patients were sensitized to at least one allergen component of Penaeus monodon, 20 patients were sensitized to crab, and 20 were sensitized to lobster. Only 15 (30%) patients were sensitized to the Northern prawn (Pandalus borealis) allergen extract in ALEX2 and only 12 (24%) to Shrimp mix (Litopenaeus setiferus, Farfantepenaeus aztecus, Farfantepenaeus dourarum).

Conclusions

Sensitization to shrimp tropomyosin in the research group was present only in 34% of cases. There may be other shrimp allergen components, not available in ALEX2, which are responsible for shrimp sensitization.

Prevalence of sensitization to molecular food allergens in Europe: A systematic review

Background

Recent reports indicate that the prevalence of food allergy is increasing, but accurate estimates remain a challenge due to cross-reactivity and limited use of precise diagnostic methods. Molecular allergy diagnostics, in which sensitization to individual molecular allergens is measured, is emerging as a promising tool for evaluation of sensitization profiles. In this systematic review, we summarized estimates of prevalence of sensitization to molecular food allergens in the general population in Europe.

Methods

Following a protocol prospectively registered with the International Prospective Register of Systematic Reviews (PROSPERO; reference CRD42021266657), we searched seven databases with no restrictions on publication date or language. Two reviewers independently screened the literature, extracted data, and appraised the risk of bias in the included studies. The findings were synthesized narratively.

Results

From 4776 de-duplicated records, five studies, with low to moderate overall risk of bias, were included. Forty-six molecular allergens from 18 foods were investigated. Overall, the prevalence of sensitization was low, particularly for major allergens, and non-existent for 10 molecular allergens (0% [95% CI 0-0.8]). The highest prevalence was seen for PR-10 proteins, such as Cor a 1.04 (13.6% [95% CI 10.9-16.9]).

Conclusions

Available data, primarily from North-western Europe, indicate that sensitization to molecular food allergens is overall low. The highest estimates were found for cross-reactive PR-10 proteins. There were not enough studies to discern regional differences or perform meta-analysis, highlighting the need for more population-representative studies in order to elucidate patterns of sensitization to molecular food allergens in Europe.

Assessment of TSLP, IL 25 and IL 33 in patients with shrimp allergy

Background

Shrimp allergy is a growing problem among the European population. TSLP, IL-25 and IL-33 are involved in the pathophysiology of allergic diseases, including asthma and atopic dermatitis, as they activate the Th2-dependent immune response.

Methods

Thirty-seven patients (18 male and 19 female) with a positive history of symptoms associated with shrimp consumption were selected. All patients had blood samples taken to assess the concentration of allergen-specific IgE (sIgE) to house dust mites (HDM) and shrimp (Singleplex, quantitative method with cut off value > 0,35 kAU/L) as well as the level of allergen components using the ImmunoCap ISAC method (Microarray test, semi-quantitative with cut off value > 0,3 ISU-E). The concentrations of TSLP, IL-25 and IL-33 in the patients’ blood serum was assessed using the ELISA method (Cusabio). Twenty patients with negative allergy history of allergic disease tests were included in the control group.

Results

Among the 37 shrimp-allergic patients, ImmunoCap ISAC was identified the presence of sIgE to the available shrimp allergen components in only 14 cases (37.8%). TSLP and IL25 levels were significantly higher in the study group. No statistically significant correlation was found between the concentration of analyzed alarmins and the concentration of sIgE level to shrimp or HDM between the study and control groups. No statistically significant correlation was found between poly-sensitization occurring in patients and levels of TSLP, IL-25 and IL-33 .

Conclusion

In shrimp-allergic patients, the concentrations of TSLP and IL-25 were significantly higher than in the control group (1.33 vs. 0.49 and 157 vs. 39.36, respectively). There was no correlation between the concentrations of TSLP, IL-25 and IL-33 and the concentration of sIgE in the patients or the number of allergen components that the patients were sensitized to.

Trial registration: Bioethics Committee 147/2015, 11.03.2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13223-021-00576-9.