pituitrin and Autoimmune-Diseases-of-the-Nervous-System

Diagnosis of autoimmune central diabetes insipidus (CDI) is based on the presence of autoantibodies to AVP-secreting cells (AVPcAb) or the coexistence of other autoimmune polyendocrine syndromes; moreover, it can be also suggested by the presence of lymphocytic infundibulo-neurohypophysitis, evidenced by biopsy of pituitary stalk and/or by pituitary stalk thickening on magnetic resonance imaging (MRI). However, so far, in clinical CDI patients with lymphocytic infundibulo-neurohypophysitis, AVPcAb have not been investigated and in those with or without autoimmune polyendocrine syndromes (APS), longitudinal studies on the behavior of AVPcAb alone, or of both AVPcAb and hypothalamic pituitary imaging on MRI are lacking. Aim of this work was to investigate in these patients the occurrence of AVPcAb (by indirect immunofluorescence) and of pituitary stalk thickening (by MRI) and their longitudinal changes during a follow-up period. We studied 22 patients, aged 29-53, with APS and complete CDI, grouped as follows: 10 with recent onset (< or =1.5 yr) of CDI (group 1a) and 12 with CDI of long-term duration (> or = 7 yr) (group 1b); moreover, a group of 13 patients with apparent idiopathic CDI of recent onset (<1.5 yr) were studied. They were divided, on the basis of the detection of AVPcAb as follows: 5 AVPcAb positive patients (aged 19-26) classified as isolated autoimmune CDI (group 2) and 8 AVPcAb negative patients (aged 21-26), classified as true idiopathic CDI (group 3). All patients were evaluated yearly, along 5 yr, for AVPcAb and for hypothalamic-pituitary region imaging. At study entry, 8/10 (80%) of patients in group 1a and 7/12 (58.3%) in group 1b were positive for AVPcAb and persisted positive subsequently, during all the follow-up period, even if at lower titers. All patients in group 2 were positive and all those in group 3 were negative for AVPcAb and persisted positive and negative, respectively, for all the follow-up study. Among the AVPcAb-positive patients, only 5 in group 1a and 2 in group 2 showed also pituitary stalk thickening at the first observations, which however spontaneously disappeared subsequently indicating a possible lymphocytic infundibulo-neurohypophysitis. All patients in the studied groups showed loss of the hyperintense signal of the neurohypophysis on MRI at entry and during all the follow-up period. Results of this longitudinal study suggest: 1) AVPcAb, frequently present at high titers in recent phases of CDI, persist subs

Topics: Adult; Autoantibodies; Autoimmune Diseases of the Nervous System; Diabetes Insipidus, Neurogenic; Female; Follow-Up Studies; Humans; Hypothalamo-Hypophyseal System; Immunoglobulin G; Longitudinal Studies; Magnetic Resonance Imaging; Male; Middle Aged; Vasopressins