Molecular Diagnosis of Allergic Contact Dermatitis (SMECA).

Summary

Allergic contact dermatitis (ACD) is a common inflammatory skin disease, which represents a major public health issue in industrialized countries. ACD is induced by repeated contact of individuals with environmental chemicals and is characterized by a delayed type IV hypersensitivity response with skin inflammation mediated by allergen-specific T cells in sensitized individuals.

The current diagnosis is based on clinical examination, assessment of environmental exposures and patch testing. Although the robustness of patch tests has long been established, this method can sometimes give inconclusive results, leading to problems in disease management.

Preliminary results indicate that the molecular analysis of Patch-Tests (PT) reactions could allow a more reliable diagnosis. Importantly, this gene profiling approach may help to identify patients with false positive PT reactions, i.e. patients whose PT reactions did not show any "allergy signature".

However, it remains to be demonstrated that the presence or absence of allergy biomarkers in PT lesions are indeed predictive of ACD response in patients.

The main objective is to describe the correlation between these molecular signatures and the reactivity of individuals when they are exposed to allergenic compounds under conditions of use (using ROAT test).

Conditions

• Eczema
• Allergic Contact Eczema Nos

Interventions

PROCEDURE

Blood sample

A blood sample (48 ml) will be collected from each patient before performing the ROAT tests. This sample will be used to perform in vitro lymphocyte proliferation test, and cytokine measurements.

PROCEDURE

Skin biopsies

2 skin biopsies will be performed at the inclusion: one from positive/doubtful patch test reaction and one from control patch test. In case of positive ROAT test, 2 additional biopsies will be collected: one from positive ROAT test reaction and one from control area. Molecular analysis will be performed.

PROCEDURE

ROAT test

ROAT test (repeated open application test) is a use test used to establish the clinical relevance of patch tests. Patients will be exposed to 3 solutions of increasing concentration containing the culprit allergen (nickel, limonene hydroperoxide or linalool hydroperoxide), as well as a solution containing the vehicle alone (control solution), 2 times a day for up to 21 days, in the absence of a reaction.

Sponsors & Collaborators

• Institut National de la Santé Et de la Recherche Médicale, France

  collaborator OTHER_GOV

• Ramsay Générale de Santé

  lead OTHER

Study Design

Allocation

NA

Purpose

DIAGNOSTIC

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-06-20

Primary Completion

2024-03-20

Completion

2024-12-20

Countries

• Belgium
• France

Study Locations