title: Neuroimmune interactions in Sjögren's syndrome: relationship of exocrine gland dysfunction with autoantibodies to muscarinic acetylcholine receptor-3 and mental health status parameters.
abstract: OBJECTIVE
  Antimuscarinic acetylcholine receptor-3 (m3AChR) autoantibodies have been described in primary Sjögren's syndrome (pSS). The aim of this study was to compare various methods for their detection and to assess the contributions of anti-m3AChR and other immunological and psychosocial factors to the pathomechanism of secondary SS (sSS).
  
  
  METHODS
  Sixty-five rheumatoid arthritis (RA) patients, 103 systemic lupus erythematosus (SLE) patients, 76 pSS patients and 50 controls were compared. Three immunodominant epitopes of m3AChR were synthesized and used in ELISA. Two extracellular epitopes were also prepared in fusion with glutathione-S-transferase and one in conjugation with bovine serum albumin. Mental health status was assessed with the 36-item Short-Form Health Survey and Functional Assessment of Chronic Illness Therapy fatigue scale. Correlations were evaluated between glandular function and anti-m3AChR positivities and specificities, features of SLE and RA, and mental health parameters.
  
  
  RESULTS
  Fourteen RA and 27 SLE patients had sSS. The autoantibody levels to all epitopes of m3AChR were significantly higher in pSS and SLE patients than in the controls. The fusion protein forms discriminated RA from pSS and SLE; furthermore, the YNIP fusion protein also distinguished pSS from SLE. The prevalence and the mean levels of all autoantibodies did not differ statistically between sicca and non-sicca SLE or RA patients. Glandular dysfunction correlated with higher age in SLE and RA and an impaired health-related quality of life in SLE.
  
  
  CONCLUSIONS
  The second and third extracellular loops of m3AChR are antigenic in pSS. Immunoassays with antigens as fusion peptides demonstrate the best performance. Sicca SLE patients have worse mental health status. Anti-m3AChR antibodies represent a peculiar example of neuroimmune interactions.
authors.affiliation: Department of Rheumatology, Faculty of Medicine, Albert Szent-Györgyi Health Centre, University of Szeged, Szeged, Hungary. drdeakmagdi@gmail.com
authors.forename: Magdolna
authors.initials: M
authors.lastname: Deák
authors.forename: Attila
authors.initials: A
authors.lastname: Szvetnik
authors.forename: Attila
authors.initials: A
authors.lastname: Balog
authors.forename: Nicolette
authors.initials: N
authors.lastname: Sohár
authors.forename: Renáta
authors.initials: R
authors.lastname: Varga
authors.forename: Gyula
authors.initials: G
authors.lastname: Pokorny
authors.forename: Gábor
authors.initials: G
authors.lastname: Tóth
authors.forename: Mária
authors.initials: M
authors.lastname: Kiss
authors.forename: László
authors.initials: L
authors.lastname: Kovács
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001324:Autoantigens / Q000097:blood / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005088:Exocrine Glands / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015213:Neuroimmunomodulation; D009483:Neuropsychological Tests; D011976:Receptors, Muscarinic / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000276:immunology* / Q000503:physiopathology* / Q000523:psychology*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D011976:Receptors, Muscarinic