Recombinant Tropomyosin- and Hemocyanin-Specific IgE in Children With Suspected Shrimp Allergy

Official title

Diagnostic Value of Recombinant Tropomyosin- and Hemocyanin-Specific IgE for the Diagnosis of IgE-Mediated Shrimp Allergy in Children in Vietnam

Overview

This study will evaluate whether blood tests that measure IgE antibodies to two shrimp proteins, tropomyosin and hemocyanin, can help diagnose shrimp allergy in children. Children with suspected IgE-mediated shrimp allergy will undergo oral food challenge, skin prick testing, and blood sampling. Oral food challenge results will be used as the reference standard to determine whether these tests can accurately identify true shrimp allergy and help improve diagnosis in clinical practice.

Detailed description

Shrimp allergy is an important cause of IgE-mediated food allergy in children, and diagnosis remains challenging because conventional tests may not reliably distinguish true clinical allergy from sensitization or cross-reactivity. Oral food challenge (OFC) remains the reference standard, but it is time-consuming, resource-intensive, and may trigger significant allergic reactions.

This interventional diagnostic study will enroll children with suspected IgE-mediated shrimp allergy. Participants will undergo OFC according to the study protocol, together with skin prick testing and blood sampling for measurement of specific IgE to recombinant tropomyosin and hemocyanin. To standardize the diagnostic procedure, OFC will be performed using black tiger shrimp (Penaeus monodon) in all participants. Additional OFCs using other shrimp species may be performed when the clinical history suggests reactions to a different shrimp species. OFC results will be used to classify participants as shrimp allergic or shrimp tolerant.

The study will estimate the proportion of true shrimp allergy among children with suspected shrimp allergy and evaluate the diagnostic performance of recombinant tropomyosin- and hemocyanin-specific IgE, alone and in combination with clinical history and skin prick test results. The findings are expected to support more accurate molecular diagnosis of shrimp allergy in children and help optimize the indication for OFC in clinical practice in Vietnam.

Interventions

• Diagnostic test Oral Food Challenge (OFC)
  Oral food challenge with shrimp performed according to the study protocol to confirm or exclude IgE-mediated shrimp allergy in children with suspected shrimp allergy. To standardize the challenge material, black tiger shrimp (Penaeus monodon) will be used in all participants. Additional oral food challenges using other shrimp species may be performed when the clinical history suggests reactions to a different shrimp species. The oral food challenge result serves as the reference standard for dia
• Diagnostic test Skin Prick Test
  Skin prick testing performed as part of the diagnostic evaluation in children with suspected IgE-mediated shrimp allergy.
• Diagnostic test Recombinant Tropomyosin- and Hemocyanin-Specific IgE Measurement
  Blood testing to measure specific IgE to recombinant tropomyosin and hemocyanin as part of the diagnostic evaluation of suspected shrimp allergy.

Primary outcome measures

• Oral Food Challenge-Confirmed IgE-Mediated Shrimp Allergy [Time frame: At the time of the oral food challenge during the baseline diagnostic evaluation]

Secondary outcome measures (3)

• Diagnostic Accuracy of Recombinant Tropomyosin-Specific IgE for Oral Food Challenge-Confirmed Shrimp Allergy [Time frame: During the baseline diagnostic evaluation]
• Diagnostic Accuracy of Recombinant Hemocyanin-Specific IgE for Oral Food Challenge-Confirmed Shrimp Allergy [Time frame: During the baseline diagnostic evaluation]
• Diagnostic Accuracy of a Combined Model Incorporating Recombinant Tropomyosin-Specific IgE, Recombinant Hemocyanin-Specific IgE, Clinical History, and Skin Prick Test [Time frame: During the baseline diagnostic evaluation]

Eligibility criteria

Inclusion criteria

• Children aged 1 to 16 years.
• Evaluated at the Allergy Unit of Children's Hospital 1.
• Clinical history suggestive of IgE-mediated shrimp allergy based on EAACI 2023 criteria, including at least 1 typical allergic symptom (urticaria, angioedema, vomiting, abdominal pain, diarrhea, cough, wheezing, dyspnea, or hypotension), symptom onset within 2 hours after shrimp ingestion, and recurrence on at least 2 separate exposures.
• Parent or legal guardian able to provide written informed consent; child assent obtained when appropriate.

Exclusion criteria

• Acute illness at the time of enrollment or challenge, including acute respiratory infection, acute gastrointestinal infection, or acute asthma exacerbation.
• Severe chronic disease, including malignancy, severe liver or kidney disease, primary immunodeficiency, or significant heart disease affecting hemodynamic status.
• Mental or behavioral disorder that prevents completion of study procedures.
• Use of immunosuppressive medication (oral corticosteroids, cytotoxic drugs, or biologic agents) within 4 weeks before enrollment, or intravenous immunoglobulin within the previous 3 months.

Exclusion criteria

• Acute illness at the time of enrollment or challenge, including acute respiratory infection, acute gastrointestinal infection, or acute asthma exacerbation; participants may be rescheduled after recovery.
• Severe chronic disease, including malignancy, severe liver or kidney disease, primary immunodeficiency, or significant heart disease affecting hemodynamic status.
• Mental or behavioral disorder that prevents completion of study procedures.
• Use of immunosuppressive medication (oral corticosteroids, cytotoxic drugs, or biologic agents) within 4 weeks before enrollment, or intravenous immunoglobulin within the previous 3 months.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

N/A

Model

Single group

Masking

Open label

Primary purpose

Diagnostic

Study locations

Vietnam · 1 center

• Children's Hospital 1 — Ho Chi Minh City

Identifiers

NCT: NCT07501325 · UMP-SHRIMP-IgE-2025

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗