title: Prevalence and functional significance of antipituitary antibodies in patients with autoimmune and non-autoimmune thyroid diseases.
abstract: BACKGROUND
  Circulating antipituitary antibodies (APA) are markers of autoimmune hypophysitis, which may cause deficient pituitary function. The prevalence of APA in autoimmune thyroid disorders (AITD) is uncertain.
  
  
  OBJECTIVE
  The aims of this study were 1) to evaluate APA prevalence in a large series of patients with AITD and non-AITD and 2) to investigate the functional significance of APA by assessing pituitary function in APA-positive patients.
  
  
  METHODS
  We conducted a health survey on consecutive AITD and non-AITD patients at a tertiary referral center (Department of Endocrinology, Pisa).
  
  
  METHODS
  Subjects, including 1290 consecutive patients with thyroid disorders (961 AITD and 329 non-AITD) and 135 controls, were enrolled in the study.
  
  
  METHODS
  APA (indirect immunofluorescence), free T(4), free T(3), TSH, and organ-specific autoantibodies were assayed in all patients. Functional pituitary evaluation was performed in most APA-positive patients.
  
  
  RESULTS
  APA frequency was higher in AITD (11.4%) than in non-AITD (0.9%; P < 0.0001) patients; all control subjects had negative APA tests. APA were more frequently found in Hashimoto's thyroiditis (13%) than in Graves' disease (7.1%; P = 0.05). Of 110 APA-positive AITD patients, 20 (18.2%) had autoimmune polyglandular syndrome, whereas 90 (81.8%) had apparently isolated AITD. APA positivity increased percentage of autoimmune polyglandular syndrome in our series from 10.4 to 13.5%. Of 110 APA-positive patients, 102 were submitted to dynamic testing for functional pituitary assessment; 36 patients (35.2%) had mild or severe GH deficiency (GHD). No additional anterior pituitary hormone deficiencies were found; one patient had central diabetes insipidus. Pituitary abnormalities at magnetic resonance imaging were found in most APA-positive GHD patients.
  
  
  CONCLUSIONS
  APA are frequently present in patients with AITD. Patients should be tested for APA because positive tests are associated with GHD.
authors.affiliation: Dipartimento di Endocrinologia, Università di Pisa, Ospedale Cisanello, via Paradisa, 2, Pisa, Italy. lmanetti@endoc.med.unipi.it
authors.forename: Luca
authors.initials: L
authors.lastname: Manetti
authors.forename: Isabella
authors.initials: I
authors.lastname: Lupi
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Morselli
authors.forename: Sonia
authors.initials: S
authors.lastname: Albertini
authors.forename: Mirco
authors.initials: M
authors.lastname: Cosottini
authors.forename: Lucia
authors.initials: L
authors.lastname: Grasso
authors.forename: Maura
authors.initials: M
authors.lastname: Genovesi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pinna
authors.forename: Stefano
authors.initials: S
authors.lastname: Mariotti
authors.forename: Fausto
authors.initials: F
authors.lastname: Bogazzi
authors.forename: Luigi
authors.initials: L
authors.lastname: Bartalena
authors.forename: Enio
authors.initials: E
authors.lastname: Martino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D002648:Child; D020790:Diabetes Insipidus, Neurogenic / Q000453:epidemiology / Q000276:immunology; D005260:Female; D006111:Graves Disease / Q000453:epidemiology / Q000276:immunology; D050031:Hashimoto Disease / Q000453:epidemiology* / Q000276:immunology*; D006306:Health Surveys; D006801:Humans; D007018:Hypopituitarism / Q000453:epidemiology* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010900:Pituitary Diseases / Q000453:epidemiology / Q000276:immunology; D016036:Seroepidemiologic Studies
chemical_list: D001323:Autoantibodies