SALAM ALEKOUM. Unité de recherche INSERM. Service Allergologie et Immunologie Clinique Lyon-Sud. Unité de recherche clinique Lyon-Sud

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1 SALAM ALEKOUM Unité de recherche INSERM Service Allergologie et Immunologie Clinique Lyon-Sud Unité de recherche clinique Lyon-Sud

2 Physiopathologie i des dermatites de contact (allergique, irritante et atopique) Vocanson M, Rozieres A, Nosbaum A, Bérard F, Nicolas JF Université Lyon1, Inserm U 1111, Allergology and Clinical Immunology, CH Lyon-Sud

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4 ECZEMAS Allergic Contact dermatitis Atopic eczema Irritant Contact Dermatitis Der P Der F Adaptive Immunity hapten, allergen DTH type IV Gell and Coombs T cell mediated Innate Immunity Inflammatory properties TLR- and inflammasomemediated

5 Take home messages CD8+ T cells mediate skin allergy Haptens (Drug allergy, contact dermatitis) and proteins (Atopic dermatitis) Phenotype Tc1 : cytotoxic and IFNg+ No need of CD4+ T cell help CD4+ T cells are regulatory CD4 Tregs control both priming and effector functions of CD8+ T cells CD4 Tregs are activated by immunization CD4+ Treg activation occurs independantly from CD8 Practical consequences Practical consequences Diagnosis of skin allergy by analysis of specific CD8+ T cells Immunotherapy targeting CD4+ Tregs Skin Vaccination to induce CD8+ effector T cells

6 ALLERGIC CONTACT DERMATITIS Contact Hypersensitivity Repeated contact with skin sensitizers called haptens Haptens HAPTENS are very diverse chemical molecules Non protein able chemicals to modify self proteins and Interact to induce with T aminoacid cell activation residues DNP et TNP: lysin ACD Ni: histidin a skin DTH reaction Hapten-specific T cells - Strong H: DNP, TNP, oxazolone Patients ACD in with 90% ACD of people have circulating specific T cells which are recruited in -Weak the skin H: to metals induce the (Ni, ACD Cr, Cu) inflammation ACD 20% of people Diagnosis of ACD rely on: - Very weak H: ACD in < 1% 1. Patch-tests t t 2. Professional Immunobiological ACD, fragrances, tests drugs

7 Immunology of eczemas Sensitization Innate response T cell priming TNF- IL-1 IL-1 IL-6 Dendritic cell Antigen Allergen Keratinocytes Mast cell Skin irritation ICD Blood vessel Epidermis Dendritic cells Recruitment of innate cells Dermis Endothelial cell Skin allergy Eczema Drug allergy Effector T cells Elicitation Effector T cell response Skin inflammation EPIDERMIS Lymphatic Th1 Th2 Th17 Blood Eosvessel Neut Mono Regulatory T cells DERMIS DC migration Lymph vessel T cell priming sensitization Treg cells LYMPH NODE Teff cells 7

8 Pathophysiology of eczemas Sensitization Innate response T cell priming TNF- IL-1 IL-1 IL-6 Antigen allergen Keratinocytes Skin irritation ICD Dendritic cells Recruitment of innate cells Elicitation Effector T cell response Skin inflammation Skin allergy Eczema Drug allergy EPIDERMIS Effector CD8+ T cells DERMIS Mast cell Dendritic cell Blood vessel Endothelial cell Regulatory CD4+ T cells DC migration T cell priming sensitization Lymph vessel CD4+ Treg cells LYMPH NODE CD8+ T eff cells 8

9 1. EFFECTOR MECHANISMS RESULTS CD8+ T cells Mouse models Sensitization (Day 0) 5 days Challenge (Day 5) Haptens (DNFB, fragrances, drugs) Proteins (house dust mite Der f) D1-D10 D10 Skin inflammation (ear swelling, histology, PCR,FACS) Specific immune responses (LN, Facs, PCR, functional assays) BOUR et al., Eur J Immunol, 1995 KRASTEVA et al., J Immunol, 1998 KEHREN et al., J Exp Med, 1999 AKIBA et al., J Immunol, 2002 SAINT-MEZARD et al. J Immunol, 2003 VOCANSON et al. J Invest Dermatol, 2006 BONNEVILLE et al. J Invest Dermatol, 2007 HENNINO et al J Immunol, 2007 ROZIERES et al, Allergy, 2009 VOCANSON et al, J Allergy Clin Immunol, 2010 HENNINO et al. J Allergy Clin Immunol, 2011 Ear swe elling (µm) Strong Haptens Protein allergens Atopic Dermatitis CD4+ T cell-deficient mice -MHC class II-/- (C57BL/6) -anti-cd4 mab treatment 200 Normal C57BL/6 or BALB/c mice CD8+ T cell-deficient mice -MHC class I-/- (C57BL/6) -anti-cd8 mab treatment Hennino et al. JImmunol, 2007 Clinically relevant haptens Allergic contact t dermatitis Drug Allergy Days after challenge CD8+ T cells are effector cells CD4+ T cells comprise regulatory T cells CD4+ T cell depleted Wild type 9 Vocanson M et al.allergy, 2009 / Rozieres A et al, Allergy 2010, in press

10 HES staining 9hrs - anti-cd8 mab staining anti-cd8 mab staining

11 2. CD4+ T cells down-regulate ACD to strong haptens Pre-clinical models CD4+ T cells control skin allergy VOCANSON et al, J Allergy Clin Immunol, 2010 HENNINO et al. J Allergy Clin Immunol, 2011 Sensitization 5 days Challenge Ear sw welling ( m) Strong allergens CD8+ ICOS+ CD4+ ICOS Days after challenge Skin immunization with strong or weak allergens activates CD4+ T cells Allergen-specific CD4+25+ T cells inhibit T cell priming and allergic responses Sensitization 5 days dlns IV transfer CD4+ T cell subsets 5 days Transferred Donors cells - PBS DNFB OXA CD4+CD25+ CD4+CD25- CD4+CD25+ CD4+CD25- DNFB-specific T cell response Sensitization % control response 11

12 2. CD4+ T cells down-regulate ACD to strong haptens following days FACS analysis SOURIS NAIVE SOURIS SENSIBILISEE (Day 0) DNFB (haptène fort) HCA (parfum)(haptène faible) Draining lymph nodes (dlns) Several allergen-specific Treg subsets are able to suppress skin inflammation ICOS is a marker for a highly suppressive Treg cell population Naive Tregs Suppr.+ Naive T cells CD D25 Gate: CD4+ cells B 10 3 D ICOS A C Eff/memory Tregs Supp. +++ Antigen-dependent B Supp +++ A A Mix population Supp ++ Antigen-dependent feration Prolif D C secretion IFNg B D C 12

13 2. CD4+ T cells down-regulate ACD to strong haptens Strong allergens potently activate Tregs which cannot control CD8+ effector T cell priming VOCANSON et al, J Allergy Clin Immunol, 2010 HENNINO et al. J Allergy Clin Immunol, 2011 Sensitization (Day 0) DNFB (haptène fort) following days draining lymph nodes (dlns) FACS analysis Naive 4,5% DNFB T reg 16% % % % %

14 3. CD4+ T cells prevent ACD to weak haptens Sensitization Challeng Fragrance allergens (HCA, EUG, HDCL) 3 sensitizations e 5 days Ear swelling measue h Œdème de l ore eille ( m m) Weak hapten Anti-CD4 mab depleted C57BL/6 Les CD4 sont tolérogènes Weak hapten C57BL/6 Souris tolérante

15 3. CD4+ T cells prevent ACD to weak haptens Weak allergens potently activate CD4+ Tregs which prevent priming of CD8+ effector T cells Sensitization (Day 0) Parfum (HCA) (haptène faible) following days draining lymph nodes (dlns) FACS analysis Isopropanol 3% HCA Tt tol 10% % % CD ICOS % % 15

16 Normal individual Sensitization Innate response Chemical Weak hapten / Fragrances T cell priming No skin irritation No skin allergy No ACD TNF- IL-1 IL-1 IL-6 Keratinocytes Mast cell Dendritic cells Recruitment of innate cells Effector CD8+ T cells Elicitation Effector T cell response Skin inflammation EPIDERMIS DERMIS Dendritic cell Blood vessel Endothelial cell Regulatory CD4+ T cells DC migration Low T cell priming sensitization Lymph vessel LYMPH NODE T cell priming 16

17 Perfume allergic patient Sensitization Innate response T cell priming TNF- IL-1 IL-1 IL-6 Keratinocytes Mast cell Chemical Allergic patients / Fragrance allergy models Skin irritation ICD Dendritic cells Recruitment of innate cells Skin allergy ACD Effector CD8+ T cells Elicitation Effector T cell response Skin inflammation EPIDERMIS DERMIS Dendritic cell Blood vessel Endothelial cell Regulatory CD4+ T cells DC migration High T cell priming sensitization Lymph vessel Treg cells LYMPH NODE Teff cells 17

18 Dermatite atopique Eczéma Dermatose inflammatoire chronique: sécheresse intense de la peau Eczéma poussées d eczéma prurit Maladie familiale fréquente APT Prévalence multipliée par 3 dans les 30 dernières années 10 à 20% des enfants d âge scolaire Début le plus souvent dans l enfance Der f entre 3 et 6 mois Guérison avant la puberté dans 75% des cas Der p Petrolatum Impact fort sur la qualité de vie Atopie: asthme et rhinite Facteurs génétiques et environnementaux Inflammation induite par les allergènes de l environnement Altération de la fonction barrière cutanée (filaggrin et lipides) 1. Darsow U, et al. J Eur Acad Dermatol Venereol 2005; 19: ; 2. Alomar A, et al. Br J Dermatol 2004; 151 Suppl. 70):3 27; 3. ISAAC Steering Committee. Lancet 1998; 351: ; 4.Lewis-Jones S. Int J Clin Pract 2006; 60:

19 Dermatite Atopique Altération de la fonction barrière - Déficit en filaggrine Filaggrin staining Normal skin Atopic dermatitis Ichtyosis skin Palmer et al., Nat Genet 2006 Morar et al. JID, 2007 Weidinger et al., JACI 2006

20 Atopic dermatitis Impairment of epidermal barrier Stratum Corneum normal: protection vis à vis des chimiques polluant et irritant, des allergènes et des microorganismes Stratum Corneum altéré

21 Dermatite Atopique - Traitement Traitement local de fond: Restaurer la barrière cutanée: Emollients «tous les jours, partout» des poussées: Anti-inflammatoires «la où il faut, quand il faut» dermo-corticoides immunomodulateurs topiques pq Education thérapeutique: ETP DA DAY Traitement systémique Methotrexate t t UV thérapie Ciclosporine et autres Immunosuppresseurs Immunobiologiques: rituximab?

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23 CHOUKRANE Unité de recherche INSERM Service Allergologie et Immunologie Clinique Lyon-Sud Unité de recherche clinique Lyon-Sud

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