title: Predictive role of the immunostaining pattern of immunofluorescence and the titers of antipituitary antibodies at presentation for the occurrence of autoimmune hypopituitarism in patients with autoimmune polyendocrine syndromes over a five-year follow-up.
abstract: BACKGROUND
  Antipituitary antibodies (APA) are frequently present in patients with autoimmune polyendocrine syndrome (APS).
  
  
  METHODS
  The aim was to evaluate the predictive value of APA for the occurrence of hypopituitarism. A total of 149 APA-positive and 50 APA-negative patients with APS and normal pituitary function were longitudinally studied for 5 yr.
  
  
  METHODS
  APA, by indirect immunofluorescence, and anterior pituitary function were assessed yearly in all patients. The risk for developing autoimmune pituitary dysfunction was calculated using survival and multivariate analysis.
  
  
  RESULTS
  Hypopituitarism occurred in 28 of 149 (18.8%) APA-positive patients but in none of the 50 APA-negative patients. The immunostaining pattern in APA-positive patients involved either isolated pituitary cells [type 1 pattern; n=99 (66.4%)] or all pituitary cells [type 2 pattern; n=50 (33.6%)]. All patients developing pituitary dysfunction throughout the study span had a type 1 pattern. Kaplan-Meier curves for cumulative survival showed a significantly higher rate for developing hypopituitarism in relation to positive APA tests (P<0.005), pattern of immunostaining (P<0.0001), and APA titers (P<0.000001). Cox regression analysis in APA-positive patients with a type 1 pattern demonstrated a significantly (P<0.0001) higher risk for the onset of hypopituitarism in relation to increasing titers of APA.
  
  
  CONCLUSIONS
  APA measurement by immunofluorescence may help to predict the occurrence of hypopituitarism but only when considering the immunostaining pattern and their titers. Combined evaluation of these parameters allows identifying patients at higher risk for pituitary autoimmune dysfunction, thus requiring a strict pituitary surveillance to disclose a preclinical phase of hypopituitarism and possibly interrupt therapeutically the progression to clinically overt disease.
authors.affiliation: Department of Clinical and Experimental Medicine and Surgery, F. Magrassi, A. Lanzara, Second University of Naples, via Pansini N. 5, 80131 Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bellastella
authors.forename: Mario
authors.initials: M
authors.lastname: Rotondi
authors.forename: Elena
authors.initials: E
authors.lastname: Pane
authors.forename: Assunta
authors.initials: A
authors.lastname: Dello Iacovo
authors.forename: Barbara
authors.initials: B
authors.lastname: Pirali
authors.forename: Liliana
authors.initials: L
authors.lastname: Dalla Mora
authors.forename: Alberto
authors.initials: A
authors.lastname: Falorni
authors.forename: Antonio Agostino
authors.initials: AA
authors.lastname: Sinisi
authors.forename: Antonio
authors.initials: A
authors.lastname: Bizzarro
authors.forename: Annamaria
authors.initials: A
authors.lastname: Colao
authors.forename: Luca
authors.initials: L
authors.lastname: Chiovato
authors.forename: Annamaria
authors.initials: A
authors.lastname: De Bellis
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000276:immunology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007018:Hypopituitarism / Q000150:complications / Q000175:diagnosis* / Q000276:immunology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000276:immunology; D016884:Polyendocrinopathies, Autoimmune / Q000150:complications / Q000276:immunology*; D011237:Predictive Value of Tests; D012044:Regression Analysis; D018709:Statistics, Nonparametric
chemical_list: D001323:Autoantibodies