Identification of Cutaneous and Blood Biomarkers Predictive of Response to Systemic Treatments During Chronic Inflammatory Skin Diseases

Chronic inflammatory skin diseases constitute a heterogeneous group of pathologies. They affect the skin but also other organs (joints, lungs, muscles, etc.). Their prognosis and response to treatments is extremely variable. The discovery of prognosis factors will help to precisely guide the treatment regimen and its intensification based on individual markers. The identification of new therapeutic targets is essential to develop new innovative treatments for inflammatory skin diseases. The main objective is to identify new cellular or molecular prognostic factors associated with treatment response at 1 year in inflammatory skin diseases. The secondary objectives are a better understanding of the pathophysiology of chronic inflammatory skin diseases, the identification of new cellular, molecular and microbiological prognostic factors associated with the clinical state after 10 years of evolution and the identification of prognostic markers of drug toxicity.

Inclusion Criteria: Patients: * Age\>18 years * Informed consent signed by the patient * Diagnosis of moderate to severe chronic inflammatory skin disease (IGA score 3 or 4) including: atopic dermatitis, psoriasis, hidradenitis suppurativa, lichen planus, cutaneous lupus, dermatomyositis, cutaneous scleroderma (=morphea), neutrophilic dermatosis, cutaneous granulomatosis, cutaneaous vasculitis, autoimmune bullous dermatosis * Or diagnosis of active leprosy (tuberculoid, lepromatous, reversion type 1, reversion type 2, hypersensitivity type 3), excluding pure neurological leprosy. Classification into 5 stages according to the Ridley and Jopling classification \[1\], Reversion reaction (type 1 reaction) and leprous erythema nodosum (type 2 reaction). Healthy controls : * Age\>18 years * Plastic surgery patients who have had any type of surgery resulting in healthy skin remnants * Informed consent signed by the patient * Absence of known cutaneous inflammatory disease. Exclusion Criteria: * Under guardianship or curatorship * Pregnant or breastfeeding woman * Lack of affiliation with a social security system * Current systemic treatment with immunosupressant (including corticosteroid therapy) or an immunomodulator or received within the last 3 months.