Endocrine Abstracts

A role of autoimmune aggression is postulated in the pathogenesis of different diseases in endocrinology. Forty to sixty percent of cases of central diabetes insipidus (CDI) are considered to be idiopathic. Primary polydipsy is a diagnosis of an exclusion of diabetes insipidus on the basis of water deprivation test, but sometimes it precedes the overt CDI. Thus the aim of this study was to define the prevalence of pituitary autoantibodies in patients with CDI and primary polydipsia.

We studied serum samples from 110 individuals: 61 – with CDI, 16 – with primary polydipsia, as defined by water deprivation test and 32 from control group matched by sex and age. Among patients with CDI: 36 had idiopathic form of the disease, 10 – postoperative, 8 – had tumors of the sellar region, 3 – head trauma, 2 – postinfectious, and 2 – due to hystiocytosis X.

We used solid-phase immunoenzyme assay and human hypophyses for evaluation of autoantibodies (membrane and cytosol fraction). Results showed high prevalence of pituitary autoantibodies in the group of CDI (50.8%) In subgroups being: idiopathic – 61.1% (22), postoperative – 20% (4), tumors – 25% (2), trauma – 2 patients, hystiocytosis – 1 patient, postinfectious – none. Prevalence of pituitary autoantibodies in group of polydipsia was 37.5% (6) Control group revealed 9.3% (3).

Data shown confirms the endowment of autoimmunity in development CDI with its significant role in idiopathic form of the disease. Our results also indicate surprisingly high prevalence of pituitary autoantibodies in group of patients with primary polydipsia which may represent the early phase of autoimmune CDI.