title: Anti-La positive, anti-Ro negative subset of primary Sjögren's syndrome: anti-La is a reality but is the disease?
abstract: OBJECTIVE
  To characterise the serological and clinical findings in primary Sjögren's syndrome in which anti-La was found without anti-Ro. We hypothesised that a significant portion of these are falsely negative for anti-Ro60.
  
  
  METHODS
  Twenty-nine sera from primary Sjögren's syndrome patients were tested for antibodies directed against La and Ro. Anti-La was detected using bovine La treated with or without DNAase and RNAase to identify potential false positivity. Anti-Ro60 antibodies were detected using HEp-2000 substrate (in which cells are transfected with human Ro60) and HEp-2 substrate. Anti-Ro60 and Ro-52 were also tested by in vitro transcription/translation followed by immunoprecipitation assay.
  
  
  RESULTS
  All 29 sera bound La, even after treatment with DNAase and RNAase. Of the 29 sera, 25 were unequivocally negative on HEp-2000 (1:40 dilution). Four samples were anti-Ro60 positive with a speckled pattern, three of the four at 1:320 dilution. Thus, false negative anti-Ro60 exists in a small fraction (14%) of the Ro-negative/La-positive primary Sjögren's patients. However, all the samples were negative for Ro60 and Ro52 by in vitro immunoprecipitation assay. Clinically these patients tended not to have salivary gland pathology characteristic of Sjögren's syndrome.
  
  
  CONCLUSIONS
  We found only a small fraction of Ro negative/La positive sera to show positive HEp-2000 pattern. These subjects did not have characteristic findings on pathological examination of minor salivary glands, suggesting these subjects have a process distinct from Sjögren's syndrome.
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Debashish
authors.initials: D
authors.lastname: Danda
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation; Department of Medicine, University of Oklahoma Health Sciences Center; and Medical Service, Department of Veterans Affairs Medical Center, Oklahoma City, USA.
authors.forename: Rohan
authors.initials: R
authors.lastname: Sharma
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, USA.
authors.forename: Dat
authors.initials: D
authors.lastname: Truong
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation; Department of Medicine, University of Oklahoma Health Sciences Center; and Medical Service, Department of Veterans Affairs Medical Center, Oklahoma City, USA.
authors.forename: Kristi A
authors.initials: KA
authors.lastname: Koelsch
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation; Department of Medicine, University of Oklahoma Health Sciences Center; and Medical Service, Department of Veterans Affairs Medical Center, Oklahoma City, USA.
authors.forename: Biji T
authors.initials: BT
authors.lastname: Kurien
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, USA.
authors.forename: Harini
authors.initials: H
authors.lastname: Bagavant
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, USA.
authors.forename: Umesh
authors.initials: U
authors.lastname: Deshmukh
authors.affiliation: Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
authors.forename: C Erick
authors.initials: CE
authors.lastname: Kaufman
authors.affiliation: Department of Oral and Maxillofacial Pathology, University of Oklahoma College of Dentistry, Oklahoma City, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Lewis
authors.affiliation: Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, USA.
authors.forename: Donald U
authors.initials: DU
authors.lastname: Stone
authors.affiliation: Oral Diagnosis and Radiology Department, University of Oklahoma College of Dentistry, Oklahoma City, USA.
authors.forename: Lida
authors.initials: L
authors.lastname: Radfar
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, USA.
authors.forename: Astrid
authors.initials: A
authors.lastname: Rasmussen
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, USA.
authors.forename: Kathy L
authors.initials: KL
authors.lastname: Sivils
authors.affiliation: The Arthritis and Clinical Immunology Program, Oklahoma Med.Research Foundation; Dept.of Medicine, University of Oklahoma Health Sciences Center; and Medical Service, Dept.of Veterans Affairs Medical Center, Oklahoma City, USA. hal-scofield@omrf.ouhsc.edu.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Scofield
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005188:False Negative Reactions; D006801:Humans; D047468:Immunoprecipitation; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012698:Serologic Tests; D012859:Sjogren's Syndrome / Q000097:blood* / Q000175:diagnosis / Q000276:immunology
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers; C035356:SS-A antibodies; C035357:SS-B antibodies