Clinical Cross Reactions Between Anacardiaceae (Cross-Anacards)

Evaluating the Correlation Between the Results of the Allergy Work-up for Different Allergens of the Anacardiaceae Family

The prevalence of food allergies has increased in recent decades, ranging from 1 to 3% of the general population. According to international literature and French national surveys, nuts today represent a group of allergens often associated with severe allergic reactions. They are responsible for 18 to 40% of deaths from food-related anaphylaxis.

Among all nuts, the prevalence of anacardiac allergies (mainly cashew and pistachio) continues to increase and has become a growing public health problem. Today, global production is estimated at 4.9 million tonnes of cashews and 1.1 million tonnes of pistachios. The resulting increased exposure may explain the increased prevalence of allergic reactions reported to these fruits. In addition, anaphylactic reactions to anacardiaceae are reported to be even more severe than those occurring in subjects allergic to peanuts.

Cashews and pistachios are known to exhibit immunological cross-reactions with one another. In fact, they have a strong sequential homology between their storage allergens Ana o 1 / Pis v 3 (7S vicilin, 78% homology); Ana o 2 / Pis v 2 (legume 11S, 80% homology) and Ana o 3 / Pis v 1 (albumin 2S, 70% homology). For this reason, some authors talk about the cashew / pistachio syndrome and associate the two allergenic sources by considering them as one, in clinical practice.

The diagnosis of allergy to nuts, and therefore to anacardiaceae, is based on a compatible clinical history, the presence of specific IgE (demonstrated by positivity to realistic skin tests and serum IgE assay), and positivity on the oral food challenge test.

In clinical practice, taking into account the cashew / pistachio syndrome, when the allergy work-up for cashew is negative, allergists tend to advise to reintroduce pistachio at home, considering the two allergens as sufficiently homologous to authorize such a practice. In this context, the investigators decided to check whether this practice, which is based mainly on in vitro homologies, is risk-free, based on the clinical experience of our center.

Study Overview

• Status: Completed
• Conditions: Suspected Allergy to Anacardiaceae

• Study Type: Observational
• Enrollment (Actual): 100

Contacts and Locations

Study Locations

• France
  • Montpellier, France, 34295
    • Uhmontpellier

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

All consecutive patients consulting at the Allergy Unit of the University Hospital of Montpellier (France) for a suspected food allergy to Anacardiaceae

Description

Inclusion criteria:

• Patient evaluated at the Allergy Unit of the University Hospital of Montpellier (France)
• Suspicion of food allergy to Anacardiaceae
• Allergy work-up for cashew and pistachio including at least skin tests, and possible specific IgE and food challenge

Exclusion criteria:

- Patients included in other trials that don't allow them to be included in the present one

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
PPV and NPV	PPV and NPV of the results of skin tests and food challenge to either cashew or pistachio to predict a concordant result for pistachio or cashew, respectively	1 day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Relative risk	Finding risk factors predictive of discrepancies between the results of the allergy work-up for cashew and pistachio	1 day

Collaborators and Investigators

• Sponsor: University Hospital, Montpellier
• Investigators: Principal Investigator: Davide CAIMMI, University Hospital, Montpellier

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2006
• Primary Completion (Actual): May 1, 2020
• Study Completion (Actual): June 1, 2020

Study Registration Dates

• First Submitted: March 9, 2020
• First Submitted That Met QC Criteria: March 9, 2020
• First Posted (Actual): March 11, 2020

Study Record Updates

• Last Update Posted (Actual): June 5, 2020
• Last Update Submitted That Met QC Criteria: June 4, 2020
• Last Verified: June 1, 2020

More Information

Terms related to this study

• Keywords: Food allergy; Skin tests; Pistachio; Food challenge; Cashew
• Additional Relevant MeSH Terms: Immune System Diseases; Hypersensitivity
• Other Study ID Numbers: RECHMPL20_0151

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: NC

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No