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Eosinophil localization to the basement membrane zone is autoantibody‐ and complement‐dependent in a human cryosection model of bullous pemphigoid
Author(s) -
Messingham Kelly N.,
Wang Jeffrey W.,
Holahan Heather M.,
Srikantha Rupasree,
Aust Samantha C.,
Fairley Janet A.
Publication year - 2016
Publication title -
experimental dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 96
eISSN - 1600-0625
pISSN - 0906-6705
DOI - 10.1111/exd.12883
Subject(s) - degranulation , immunology , eosinophil , immunoglobulin e , eosinophil peroxidase , antibody , bullous pemphigoid , complement system , eosinophil cationic protein , biology , microbiology and biotechnology , chemistry , receptor , biochemistry , asthma
Bullous pemphigoid ( BP ) is an autoimmune blistering disease characterized by antibodies (IgG and IgE) targeting cell‐substrate adhesion proteins. A variety of BP models suggest that autoantibody‐dependent neutrophil degranulation is essential for blister formation. However, lesional biopsies reveal a predominance of eosinophils and few neutrophils. Our goal was to evaluate the role of antibodies and complement in eosinophil localization, degranulation and split formation at the dermo‐epidermal junction ( DEJ ) utilizing a human skin cryosection model of BP paired with a human eosinophilic cell line, 15HL‐60. Expression of receptors for IgG (FcγRII), IgE (FcεRI) and complement (CR1 and CR3) was confirmed on 15HL‐60 cells using flow cytometry. 15HL‐60 expression of granule protein [eosinophil derived neurotoxin (EDN) and eosinophil peroxidase ( EPO )] m RNA and their degranulation in vitro was confirmed using RT‐PCR and ELISA, respectively. For cryosection experiments, BP or control sera or IgG and IgE antibodies purified from BP sera were utilized in combination with 15HL‐60 cells ± fresh complement. Both BP serum and fresh complement were required for localization of 15‐HL60 cells to the DEJ. Interestingly, eosinophil localization to the DEJ was dependent on IgG, but not IgE, and complement. However, no subepidermal split was observed. Additionally, the 15HL‐60 cells did not degranulate under any experimental conditions and direct application of cell lysate to cryosections did not result in a split. Our observation that eosinophil localization to the DEJ is dependent on IgG mediated complement fixation provides additional insight into the sequence of events during the development of BP lesions.