title: IgA and IgG autoantibodies against alpha-fodrin as markers for Sjögren's syndrome. Systemic lupus erythematosus.
abstract: OBJECTIVE
  To determine the prevalence of IgA and IgG autoantibodies against alpha-fodrin in patients with primary and secondary Sjögren's syndrome (SS) and controls.
  
  
  METHODS
  An ELISA detecting IgA and IgG antibodies against alpha-fodrin was developed. We examined the prevalence of IgA and IgG antibodies against alpha-fodrin in patients with primary and secondary SS, systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA) and blood donors.
  
  
  RESULTS
  IgA antibodies against alpha-fodrin were detected in 64% of patients with primary SS (n = 85), 47% of patients with secondary SS and SLE (n = 15), and 86% of patients with secondary SS and RA (n = 7). IgA autoantibodies against alpha-fodrin were detected in only one of 160 sera obtained from blood donors and in one of 50 and 2 of 12 sera obtained from SLE and RA patients without sicca syndrome, respectively. The prevalence of IgG antibodies against alpha-fodrin in SS was lower: they were detected in 55% of sera obtained from patients with primary SS, 40% of patients with secondary SS and SLE, and in 43% of patients with secondary SS and RA. Three of 160 sera from blood donors and one of 50 and 5 of 12 sera from SLE and RA patients without sicca syndrome, respectively, contained IgG antibodies against alpha-fodrin.
  
  
  CONCLUSIONS
  IgA rather than IgG antibodies against alpha-fodrin are specific for and frequently observed in primary and secondary SS and are useful markers for this autoimmune disorder.
authors.affiliation: Abteilung Klinische Immunologie, Medizinische Hochschule Hannover, Germany. witte.torsten@mh.hannover.de
authors.forename: T
authors.initials: T
authors.lastname: Witte
authors.forename: T
authors.initials: T
authors.lastname: Matthias
authors.forename: F C
authors.initials: FC
authors.lastname: Arnett
authors.forename: H H
authors.initials: HH
authors.lastname: Peter
authors.forename: K
authors.initials: K
authors.lastname: Hartung
authors.forename: C
authors.initials: C
authors.lastname: Sachse
authors.forename: R
authors.initials: R
authors.lastname: Wigand
authors.forename: A
authors.initials: A
authors.lastname: Braner
authors.forename: J R
authors.initials: JR
authors.lastname: Kalden
authors.forename: H J
authors.initials: HJ
authors.lastname: Lakomek
authors.forename: R E
authors.initials: RE
authors.lastname: Schmidt
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000276:immunology; D001323:Autoantibodies / Q000032:analysis*; D015415:Biomarkers; D001782:Blood Donors; D002352:Carrier Proteins / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D007074:Immunoglobulin G / Q000032:analysis*; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology; D008297:Male; D008840:Microfilament Proteins / Q000276:immunology*; D008875:Middle Aged; D012859:Sjogren's Syndrome / Q000150:complications / Q000276:immunology*; D013049:Spectrin
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D002352:Carrier Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008840:Microfilament Proteins; D013049:Spectrin