Median eminence dopaminergic nerve terminals: a novel target in autoimmune polyendocrine syndrome?
BACKGROUND
Autoantibodies to adenohypophyseal endocrine cells or to vasopressin neurohypophyseal neurons have long been known. Conversely, autoimmune targeting of further hypothalamic-hypophyseal structures, such as the blood-brain barrier-deprived median eminence, has been little studied.


OBJECTIVE
We studied a case of autoimmune polyendocrine syndrome type I with GH secretory deficiency, a distinctly rare event in autoimmune polyendocrine syndrome type I. We used rat and bovine tissue substrates to study autoantibodies against hypothalamic-hypophyseal nerve structures and endocrine cells.


RESULTS
In the study case, circulating autoantibodies selectively decorated median eminence dopaminergic nerve terminals, as well as pituitary gonadotropes, but not GHRH nerve terminals or pituitary somatotropes. Such autoantibodies appeared de novo in parallel with the onset of GH secretory deficiency, whereas no median eminence labeling was found in patients suffering of idiopathic GH deficiency (n = 7) or in healthy controls (n = 23).


CONCLUSIONS
The pathophysiological significance of our patient's autoantibodies remains to be confirmed. Nonetheless, the heterogeneous neuroendocrine structures of the median eminence are pointed out as potential immune targets, relevant to autoimmune polyendocrinopathy, as well as to a wide range of other conditions.
Cocco
Cristina
C
NEF-Laboratory, Department of Cytomorphology, University of Calgari at Monseratto, 09042 Monserrato (Cagliari), Italy.
Meloni
Antonella
A
Boi
Francesco
F
Pinna
Giovanni
G
Possenti
Roberta
R
Mariotti
Stefano
S
Ferri
Gian-Luca
GL
D000293:Adolescent; D000818:Animals; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000276:immunology; D001323:Autoantibodies / Q000097:blood; D002417:Cattle; D002648:Child; D002675:Child, Preschool; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology; D019382:Human Growth Hormone / Q000172:deficiency / Q000378:metabolism; D006801:Humans; D008297:Male; D008473:Median Eminence / Q000276:immunology*; D016884:Polyendocrinopathies, Autoimmune / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014446:Tyrosine 3-Monooxygenase / Q000276:immunology
D001323:Autoantibodies; D019382:Human Growth Hormone; D007987:Gonadotropin-Releasing Hormone; D014446:Tyrosine 3-Monooxygenase; D001142:Aromatic-L-Amino-Acid Decarboxylases