Pathophysiological Study of Allergic Contact Dermatitis to Para-Phenylenediamine (PPD). Analysis of Cellular and Molecular Targets in Skin Inflammation

Study Overview
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Brief Summary
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The current knowledge of the pathophysiology of allergic contact dermatitis is based on the murine model. In this model, CD8+ T cells are effector cells, and CD4+ T cells regulate the response by limiting the expansion of CD8+ T cells. The goal of this study is to characterize the pathophysiology of contact dermatitis, with patients allergic to para-phenylenediamine (PPD). We suppose that the CD8+ T cells are the effectors of the allergic contact dermatitis, although the regulator cells belong to the LT CD4+ population. We will test our hypothesis on blood samples, and cutaneous biopsies of patients allergic to PPD.

Official Title
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Pathophysiological Study of Allergic Contact Dermatitis to Para-Phenylenediamine (PPD). Analysis of Cellular and Molecular Targets in Skin Inflammation

Conditions
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Allergic Contact Dermatitis

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: For both groups: Patients aged from 18 to 65 years old. Both genders eligible for study. Female participants must use a contraceptive method. Feasibility of patch testing. Participants must be able to understand and sign the Informed Consent, and comply with all aspects of the protocol. Patients must be registered in a social security system or with a health insurance coverage  First group: allergic patients Patients with allergic contact dermatitis to para-phenylenediamine (PPD) based on a history of PPD contact dermatitis and positive PPD patch tests.  Second group : healthy volunteers No history of PPD allergic contact dermatitis, with a negative PPD patch test. Exclusion Criteria: Pregnant or lactating women. Evolutive skin disease on the testing zone (lower back). Patients with a clinically significant disease (chronic, recurrent or active). Systemic corticotherapy or immunosuppressive treatment during the previous month, or local corticoid treatment the week before the patch testing. Local or systemic drug use which interacts with the outcome measures. Exposure to sun or UV radiations, 15 days before the patch testing. Patients deprived of their civic rights, in custody, or subject to a tutorial, judiciary or administrative decision. Patients subject to a protection measure. Patients in a critical medical situation. Patients with a personal situation judged by the investigator as unlikely to be compatible with optimal participation in the study, or which could constitute a risk for the patient. Linguistic barrier or psychological profile preventing the patient from signing the consent form. Patient still in an exclusion period following the participation in another clinical trial. Patients having earned more than 4500€ in indemnities for participation in clinical trials during the previous 12 months, including this study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Allergic contact dermatitis, para-phenylenediamine, effector cells, regulatory cells, pathophysiology