title: Identification of tear lipocalin as a novel autoantigen target in Sjögren's syndrome.
abstract: Sjögren's syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration and tissue damage mainly confined to the salivary and lacrimal glands, resulting in dryness of mouth and eyes. Since different epithelial cells of exocrine and non-exocrine tissues are primarily affected, an autoimmune reaction against antigens commonly expressed in epithelial cells is believed to play a pathogenic role. To identify novel autoantigen targets associated with the systemic involvement in SS, we screened a random peptide library with pooled IgG immunoglobulins derived from patients with primary SS. Among the identified peptides, one was recognized by the majority of patients' sera, but not by sera of normal donors and of patients with other autoimmune diseases. The peptide showed homology with an Epstein-Barr Virus (EBV) derived protein and with tear lipocalin, a protein highly expressed in tears and saliva, and with alpha-fodrin, a cytoskeleton protein considered an important autoantigen target in SS. Anti-peptide antibodies affinity purified from patients' sera recognize the viral protein, tear lipocalin and alpha-fodrin. Our findings suggest that EBV infection may be linked to the pathogenesis of SS and that tear lipocalin can be considered a novel and yet unidentified autoantigen in SS.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Verona, Policlinico GB Rossi, Piazzale LA Scuro 10, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Navone
authors.forename: Claudio
authors.initials: C
authors.lastname: Lunardi
authors.forename: Roberto
authors.initials: R
authors.lastname: Gerli
authors.forename: Elisa
authors.initials: E
authors.lastname: Tinazzi
authors.forename: Dimitri
authors.initials: D
authors.lastname: Peterlana
authors.forename: Caterina
authors.initials: C
authors.lastname: Bason
authors.forename: Roberto
authors.initials: R
authors.lastname: Corrocher
authors.forename: Antonio
authors.initials: A
authors.lastname: Puccetti
mesh_terms: D000956:Antigens, Viral / Q000276:immunology; D001324:Autoantigens / Q000302:isolation & purification / Q000378:metabolism*; D015153:Blotting, Western; D002352:Carrier Proteins / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D019169:Jurkat Cells; D054835:Lipocalin 1; D008840:Microfilament Proteins / Q000276:immunology; D019151:Peptide Library; D012859:Sjogren's Syndrome / Q000276:immunology*; D013666:Tears / Q000276:immunology*; D013049:Spectrin
chemical_list: D000956:Antigens, Viral; D001324:Autoantigens; D002352:Carrier Proteins; D007074:Immunoglobulin G; D054835:Lipocalin 1; D008840:Microfilament Proteins; D019151:Peptide Library; D013049:Spectrin; C518443:LCN1 protein, human