title: Detection of antipituitary and antihypothalamus antibodies to investigate the role of pituitary or hypothalamic autoimmunity in patients with selective idiopathic hypopituitarism.
abstract: OBJECTIVE
  Antipituitary (APA) but not antihypothalamus antibodies (AHA) have been investigated in patients with idiopathic hypopituitarism. This study searched for APA and AHA in some of these patients to investigate whether pituitary or hypothalamic autoimmunity could play a role in their pituitary dysfunction.
  
  
  METHODS
  Sixty-six patients with selective idiopathic hypopituitarism were studied: 27 with ACTH deficiency, 20 with GH deficiency and 19 with hypogonadotropic hypogonadism. Twenty patients with hypopituitarism secondary to hypophysectomy and 50 healthy subjects were enrolled as controls.
  
  
  METHODS
  Antipituitary and AHA were evaluated by indirect immunofluorescence in sera of patients and controls. Positive sera were retested by a four-layer double immunofluorescence to identify the cells targeted by these antibodies.
  
  
  RESULTS
  Antipituitary were present at high titre in 4 of 27 patients with ACTH deficiency (14·8%), 4 of 20 with GH deficiency (26%) and 5 of 19 with hypogonadotropic hypogonadism (21%) and targeted, respectively, corticotrophs, somatotrophs and gonadotrophs. AHA were found at high titre only in 5 patients with ACTH deficiency (18·5%), mostly targeting corticotrophin-releasing hormone-secreting cells; none of these 5 patients resulted positive for antipituitary antibodies. Among the controls, only 1 hypophysectomized patient resulted APA positive at low titre.
  
  
  CONCLUSIONS
  Our results suggest that in patients with selective idiopathic hypopituitarism, detection of APA or AHA could better characterize an autoimmune process involving the pituitary or hypothalamus, respectively. In particular, detection of antibodies targeting selectively ACTH-secreting or corticotrophin-releasing hormone-secreting cells may differentiate, respectively secondary from tertiary variants of autoimmune hypoadrenalism.
authors.affiliation: Department of Clinical and Experimental Medicine and Surgery, F. Magrassi, A. Lanzara, Second University of Naples, Naples, Italy. annamaria.debellis@unina2.it
authors.forename: Annamaria
authors.initials: A
authors.lastname: De Bellis
authors.forename: Elena
authors.initials: E
authors.lastname: Pane
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bellastella
authors.forename: Antonio A
authors.initials: AA
authors.lastname: Sinisi
authors.forename: Caterina
authors.initials: C
authors.lastname: Colella
authors.forename: Roberta
authors.initials: R
authors.lastname: Giordano
authors.forename: Claudia
authors.initials: C
authors.lastname: Giavoli
authors.forename: Andrea
authors.initials: A
authors.lastname: Lania
authors.forename: Maria R
authors.initials: MR
authors.lastname: Ambrosio
authors.forename: Carolina
authors.initials: C
authors.lastname: Di Somma
authors.forename: Maria C
authors.initials: MC
authors.lastname: Zatelli
authors.forename: Emanuela
authors.initials: E
authors.lastname: Arvat
authors.forename: Annamaria
authors.initials: A
authors.lastname: Colao
authors.forename: Antonio
authors.initials: A
authors.lastname: Bizzarro
authors.forename: Antonio
authors.initials: A
authors.lastname: Bellastella
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000172:deficiency; D000328:Adult; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D015551:Autoimmunity / Q000276:immunology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000379:methods; D019382:Human Growth Hormone / Q000172:deficiency; D006801:Humans; D007016:Hypophysectomy / Q000009:adverse effects; D007018:Hypopituitarism / Q000097:blood / Q000209:etiology / Q000276:immunology*; D007031:Hypothalamus / Q000276:immunology* / Q000378:metabolism; D008297:Male; D010902:Pituitary Gland / Q000276:immunology* / Q000378:metabolism
chemical_list: D001323:Autoantibodies; D019382:Human Growth Hormone; D000324:Adrenocorticotropic Hormone