Autoantibodies to type VII collagen mediate Fcgamma-dependent neutrophil activation and induce dermal-epidermal separation in cryosections of human skin.
Epidermolysis bullosa acquisita is an autoimmune subepidermal blistering disease associated with autoantibodies to type VII collagen, the major constituent of anchoring fibrils. Previous attempts to demonstrate the blister-inducing potential of autoantibodies to this protein have failed. To address this question, we used an in vitro model involving cryosections of human skin incubated with patients' autoantibodies and leukocytes from healthy donors. We show that sera from 14 of 16 epidermolysis bullosa acquisita patients, in contrast to sera from healthy controls, induced dermal-epidermal separation in the cryosections. Recruitment and activation of neutrophils at the dermal-epidermal junction was necessary for split induction, whereas mononuclear cells were not required. Importantly, patients' autoantibodies affinity-purified against a recombinant form of the noncollagenous 1 domain of type VII collagen retained their blister-inducing capacity in a dose-dependent manner, whereas patients' IgG that was depleted of reactivity to type VII collagen lost this ability. Monoclonal antibody LH7.2 to the noncollagenous 1 domain of type VII collagen also induced subepidermal splits in the cryosections; F(ab')(2) fragments of autoantibodies to type VII collagen were not pathogenic. We demonstrate the capacity of autoantibodies to type VII collagen to trigger an Fcgamma-dependent inflammation leading to split formation in cryosections of human skin.
Sitaru
Cassian
C
Department of Dermatology, University of Würzburg, Würzburg, Germany.
Kromminga
Arno
A
Hashimoto
Takashi
T
Bröcker
Eva B
EB
Zillikens
Detlef
D
D000818:Animals; D001323:Autoantibodies / Q000008:administration & dosage / Q000502:physiology*; D001768:Blister / Q000276:immunology*; D001769:Blood / Q000276:immunology; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D024143:Collagen Type VII / Q000276:immunology*; D016616:Cryoultramicrotomy; D004305:Dose-Response Relationship, Drug; D016107:Epidermolysis Bullosa Acquisita / Q000097:blood; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007313:Insecta / Q000166:cytology; D007962:Leukocytes / Q000502:physiology; D008875:Middle Aged; D009504:Neutrophils / Q000502:physiology*; D010446:Peptide Fragments / Q000276:immunology; D017434:Protein Structure, Tertiary / Q000502:physiology; D017452:Receptors, IgG / Q000502:physiology*; D011971:Receptors, Immunologic / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D012867:Skin / Q000473:pathology / Q000503:physiopathology
D001323:Autoantibodies; D024143:Collagen Type VII; C052643:F(ab')2 receptor; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G; D010446:Peptide Fragments; D017452:Receptors, IgG; D011971:Receptors, Immunologic; D011994:Recombinant Proteins