title: Elevated immunoglobulin to tissue KLK11 in patients with Sjögren syndrome.
abstract: OBJECTIVE
  We have previously reported that mouse kallikrein (KLK) 22 in the lacrimal and salivary glands is an autoantigen that can induce primary Sjogren syndrome (SS) in rats. In this study, we determine whether the production of antibodies against tissue KLK is specific for SS and whether the antibody can be used as a biomarker for the diagnosis in humans.
  
  
  METHODS
  Sera from 11 patients diagnosed with SS, 8 patients with dry eye disease (DED), and 8 normal age/sex-matched controls (NL) were collected for detecting antibodies against tissue KLK1, KLK11, KLK12, and KLK13 by capture enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Anti-KLK11 antibody was significantly higher in the SS than in the DED (P = 0.05) and NL (P < 0.01) groups, with no difference in the level of this antibody between the DED and NL groups. In addition, receiver operating characteristic analysis revealed that, at or above an optical density cutoff point of 0.2695, anti-KLK11 antibody has a sensitivity of 82% and a specificity of 94% to distinguish the SS group from the other groups.
  
  
  CONCLUSIONS
  Our results suggest that anti-KLK11 might be a novel biomarker for SS in humans. Further investigation is required to confirm this finding and to establish the exact role of KLK11 in the pathogenesis of SS.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA.
authors.forename: Jaafar
authors.initials: J
authors.lastname: El Annan
authors.forename: Guomin
authors.initials: G
authors.lastname: Jiang
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: John
authors.initials: J
authors.lastname: Zhou
authors.forename: Gary N
authors.initials: GN
authors.lastname: Foulks
authors.forename: Hui
authors.initials: H
authors.lastname: Shao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D001324:Autoantigens / Q000276:immunology*; D015415:Biomarkers; D015352:Dry Eye Syndromes / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D012697:Serine Endopeptidases / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D015415:Biomarkers; D007074:Immunoglobulin G; C114880:trypsin-like serine protease; D012697:Serine Endopeptidases