Detection of vasopressin cell antibodies in some patients with autoimmune endocrine diseases without overt diabetes insipidus.

OBJECTIVE: Cytoplasmic autoantibodies to vasopressin cells (AVP) have been detected in patients with idiopathic central diabetes insipidus and only in one patient with endocrine autoimmune diseases without clinical diabetes insipidus. The aim of this study was to look for AVP cell antibodies (AVP-cell-Ab) in human sera of a large population of autoimmune endocrine disease patients without diabetes insipidus and to test whether an occurrence of these antibodies in some patients can be associated with partial impairment of posterior pituitary function. MEASUREMENT: Sera from 410 patients (310 females, 100 males, age range 10-46 years) with autoimmune endocrine disorders (260 with thyroid autoimmune disease, and 150 with insulin dependent diabetes mellitus) without clinical diabetes insipidus, and from 100 normal subjects, were investigated for hypothalamic autoantibodies by an indirect immunofluorescence method. Positive sera were subsequently tested with specific rabbit anti AVP serum.
RESULTS: None of controls, but five out of 410 patients (1.2%) were AVP-cell-Ab positive. All positive and nine negative from the 410 screened patients were tested for posterior pituitary function. Two out of five AVP-cell-Ab positive patients showed partial diabetes insipidus.
CONCLUSION: AVP cell antibodies can be shown in some patients with endocrine autoimmune disease without diabetes insipidus and can sometimes be associated with findings of partial posterior pituitary dysfunction. This suggests that clinical diabetes insipidus could be preceded by a long subclinical period characterized only by the occurrence of AVP-cell-Ab in the sera associated or followed by alterations in functional tests. Longitudinal studies are needed to confirm this hypothesis.