title: Intermediate lobe immunoreactivity in a patient with suspected lymphocytic hypophysitis.
abstract: Lymphocytic hypophysitis is an organ-specific autoimmune disease characterised by destruction of pituitary hormone-secreting cells due to attack by self-reactive T lymphocytes. The spectrum of pituitary autoantibodies characterised by indirect immunofluorescence (IF) in these patients has not been substantially defined. The purpose of this study was to determine the spectrum of pituitary autoantibodies in 16 lymphocytic hypophysitis patients. Pituitary sections were prepared from guinea pigs and sera from 16 lymphocytic hypophysitis patients (13 biopsy proven and 3 suspected cases) and 13 healthy controls were evaluated for immunoreactivity to the pituitary tissue by immunofluorescence. A single patient was found to have high titre pituitary autoantibodies against guinea pig pituitary tissue. Immunoreactivity was directed against cells of the intermediate lobe. We present the case report of the patient who is a 24 year old woman that presented with headaches, polyuria and polydipsia. A uniformly enlarged pituitary mass was visible on MRI and a diagnosis of suspected lymphocytic hypophysitis was made. Based on our IF study, we postulate this patient has an autoimmune process directed towards the major cell type in the intermediate lobe, the melanotroph. Pre-adsorption with peptides representing adrenocorticotropic hormone, α-melanocyte stimulating hormone or β-endorphin did not affect the IF signal suggesting our patient's pituitary autoantibodies may target some other product of Proopiomelanocortin (POMC) processing, such as corticotrophin-like intermediate peptide or γ-lipoprotein. Alternatively, the autoantibodies may target a peptide completely unrelated to POMC processing.
authors: Department of Paediatric Endocrinology and Diabetes, John Hunter Children's Hospital, New Lambton Heights, NSW, Australia.
authors: Casey Jo Anne
authors: CJ
authors: Smith
authors: Sophie
authors: S
authors: Bensing
authors: Vicki E
authors: VE
authors: Maltby
authors: Mingdong
authors: M
authors: Zhang
authors: Rodney J
authors: RJ
authors: Scott
authors: Roger
authors: R
authors: Smith
authors: Olle
authors: O
authors: Kämpe
authors: Tomas
authors: T
authors: Hökfelt
authors: Patricia A
authors: PA
authors: Crock
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D006801:Humans; D007018:Hypopituitarism / Q000276:immunology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010902:Pituitary Gland / Q000276:immunology* / Q000473:pathology; D011333:Pro-Opiomelanocortin / Q000276:immunology / Q000378:metabolism
chemical_list: D001323:Autoantibodies; D011333:Pro-Opiomelanocortin