title: Detection of pituitary antibodies by immunofluorescence: approach and results in patients with pituitary diseases.
abstract: BACKGROUND
  Pituitary antibodies have been measured mainly to identify patients whose disease is caused or sustained by pituitary-specific autoimmunity. Although reported in over 100 publications, they have yielded variable results and are thus considered of limited clinical utility.
  
  
  OBJECTIVE
  Our objectives were to analyze all publications reporting pituitary antibodies by immunofluorescence for detecting the major sources of variability, to experimentally test these sources and devise an optimized immunofluorescence protocol, and to assess prevalence and significance of pituitary antibodies in patients with pituitary diseases. STUDY DESIGN AND OUTCOME MEASURES: We first evaluated the effect of pituitary gland species, section fixation, autofluorescence quenching, blockade of unwanted antibody binding, and use of purified IgG on the performance of this antibody assay. We then measured cross-sectionally the prevalence of pituitary antibodies in 390 pituitary cases and 60 healthy controls, expressing results as present or absent and according to the (granular, diffuse, perinuclear, or mixed) staining pattern.
  
  
  RESULTS
  Human pituitary was the best substrate to detect pituitary antibodies and yielded an optimal signal-to-noise ratio when treated with Sudan black B to reduce autofluorescence. Pituitary antibodies were more common in cases (95 of 390, 24%) than controls (3 of 60, 5%, P = .001) but did not discriminate among pituitary diseases when reported dichotomously. However, when expressed according to their cytosolic staining, a granular pattern was highly predictive of pituitary autoimmunity (P < .0001).
  
  
  CONCLUSIONS
  We report a comprehensive study of pituitary antibodies by immunofluorescence and provide a method and an interpretation scheme that should be useful for identifying and monitoring patients with pituitary autoimmunity.
authors.affiliation: Department of Pathology (A.R., A.D.R., M.A.L.-S., L.D.V., S.I., P.C), Department of Medicine, Division of Endocrinology, Metabolism, and Diabetes, and the Pituitary Center (G.S.W., R.S.), The Johns Hopkins University School of Medicine, and Feinstone Department of Molecular Microbiology and Immunology (P.C.), The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205; Department of Pharmacy (A.R.), Gabriele d' Annunzio University, 66100 Chieti, Italy; Division of Endocrinology, Diabetology, and Metabolism, Department of Medical Sciences (F.G.), University of Turin, 10124 Turin, Italy; Department of Clinical and Experimental Medicine, Section of Endocrinology (I.L.), University of Pisa, 56126 Pisa, Italy; and Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine (S.I.), Nagoya, 466-8550 Japan.
authors.forename: Adriana
authors.initials: A
authors.lastname: Ricciuti
authors.forename: Alessandra
authors.initials: A
authors.lastname: De Remigis
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Landek-Salgado
authors.forename: Ludovica
authors.initials: L
authors.lastname: De Vincentiis
authors.forename: Federica
authors.initials: F
authors.lastname: Guaraldi
authors.forename: Isabella
authors.initials: I
authors.lastname: Lupi
authors.forename: Shintaro
authors.initials: S
authors.lastname: Iwama
authors.forename: Gary S
authors.initials: GS
authors.lastname: Wand
authors.forename: Roberto
authors.initials: R
authors.lastname: Salvatori
authors.forename: Patrizio
authors.initials: P
authors.lastname: Caturegli
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000032:analysis* / Q000276:immunology; D015551:Autoimmunity / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D010900:Pituitary Diseases / Q000276:immunology*; D010902:Pituitary Gland / Q000276:immunology*
chemical_list: D001323:Autoantibodies