title: Salivary IgA and IgG antibodies to bullous pemphigoid 180 noncollagenous domain 16a as diagnostic biomarkers in mucous membrane pemphigoid.
abstract: BACKGROUND
  Mucous membrane pemphigoid (MMP) is an uncommon mucocutaneous immunobullous disorder. Use of saliva for diagnosis by enzyme-linked immunosorbent assay (ELISA) using the noncollagenous (NC) domain 16a of bullous pemphigoid antigen II (BP180) is not well described.
  
  
  OBJECTIVE
  To establish whether whole or parotid saliva is a suitable alternative to serum for diagnosis of MMP.
  
  
  METHODS
  Precoated BP180-NC16a ELISA plates were used to test serum, and whole and parotid saliva for IgG, IgA and secretory IgA antibodies. Patients with MMP (n = 64) provided matched serum and whole saliva. In addition 18 of the MMP patients also provided matched parotid saliva. Healthy controls (n = 50) provided matched serum and whole saliva and 6 of these additionally provided matched parotid saliva. An additional 16 disease controls provided matched serum, and whole and parotid saliva.
  
  
  RESULTS
  In whole saliva, IgG antibodies were detected in 11/64 (17%), IgA in 23/64 (36%) and a combined positivity in 29/64 (45%). In parotid saliva, IgA antibodies were found in 8/18 (44%). Serum IgG antibodies were detected in 27/64 (42%), serum IgA antibodies in 18/64 (28%) and a combined positivity in 33/64 (52%). Combined use of serum and saliva increased detection of specific antibodies by 30%. Control samples were all negative (positive predictive value of 100% for all tests). The negative predictive values were 62% for IgA saliva, 65% for IgG serum, 59% for IgA serum and 56% for IgG saliva.
  
  
  CONCLUSIONS
  IgG and IgA antibodies may provide a suitable diagnostic marker in MMP. Assay of salivary IgA antibodies to NC16a offers a similar diagnostic predictive value to serum.
authors.affiliation: Mucosal and Salivary Biology Division, Dental Institute, King's College London, London, U.K.|King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: S
authors.identifier: http://orcid.org/0000-0003-0117-6596
authors.initials: S
authors.lastname: Ali
authors.affiliation: Mucosal and Salivary Biology Division, Dental Institute, King's College London, London, U.K.
authors.forename: C
authors.initials: C
authors.lastname: Kelly
authors.affiliation: Mucosal and Salivary Biology Division, Dental Institute, King's College London, London, U.K.
authors.forename: S J
authors.initials: SJ
authors.lastname: Challacombe
authors.affiliation: Biostatistics and Research Methods Centre, Dental Institute, King's College London, U.K.
authors.forename: A N A
authors.initials: AN
authors.lastname: Donaldson
authors.affiliation: The National Institute of Health Research Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, U.K.
authors.forename: J K G
authors.initials: JK
authors.lastname: Dart
authors.affiliation: Department of Ear Nose and Throat, Guy's and St Thomas' Hospital NHS Foundation Trust, London, U.K.
authors.forename: M
authors.initials: M
authors.lastname: Gleeson
authors.affiliation: Mucosal and Salivary Biology Division, Dental Institute, King's College London, London, U.K.|St John's Institute of Dermatology, Guy's and St Thomas' Hospital NHS Foundation Trust, London, U.K.
authors.forename: J F
authors.initials: JF
authors.lastname: Setterfield
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001323:Autoantibodies / Q000378:metabolism; D001324:Autoantigens / Q000276:immunology; D015415:Biomarkers / Q000378:metabolism; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism*; D007074:Immunoglobulin G / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010390:Pemphigoid, Benign Mucous Membrane / Q000175:diagnosis* / Q000276:immunology; D010391:Pemphigoid, Bullous / Q000276:immunology*; D012463:Saliva / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D015415:Biomarkers; D007070:Immunoglobulin A; D007074:Immunoglobulin G