A Study of Anti-Pituitary-Antibodies in Patients with Hypopituitarism and Their Hereditary Background

Abstract

Recently several types of anti-pituitary-antibodies (APA) have been found in patients with pituitary disorders including hypopituitarism and diabetes insipidus, and in postpartum women. However, the pathophysiological role(s) of APA still remains unknown. In order to elucidate the clinical significance of APA, longitudinal follow-up and family study of APA in patients with hypopituitarism were performed. APA in serum was examined in a total of 11 patients with various types of hypopituitarism (7 of isolated ACTH deficiency, 1 of partial hypopituitarism, 3 of Sheehan's syndrome, 6 males and 5 females). Chronic thyroiditis was associated in 3 out of 7 patients with isolated ACTH deficiency, and empty sella was found in each one patient with isolated ACTH deficiency and partial hypopituitarism, and in 3 patients with Sheehan's syndrome. APA was examined on 2 or 3 occasions at more than a 6 month interval (longitudinal study). In 5 patients, their 16 family members were examined for the presence of APA, and pituitary functions were evaluated in 3 out of 7 family members with positive APA (family study). For pituitary function tests, arginine infusion test, TRH, LH-RH or CRH test and insulin tolerance test were performed. APA reacting to rat pituitary cytoplasmic antigens (pituitary cell antibodies: PCA) and APA reacting to rat GH3 cells and/or mouse AtT20 cells surface antigens (pituitary cell surface antibodies: PCSA) were assayed with indirect immunofluorescence method. At the initial examination, 6 out of 11 patients (55%) showed positive APA. The patients were divided into 3 subgroups according to the longitudinal study: the group with disappearance of initially positive APA (3 patients), the group with altered titers or types of initially positive APA (3 patients), and the group with sustained initially negative APA (4 patients). No effects of replacement therapy on the alterations of APA were observed. In 16 family members of 5 patients (each 1 with partial hypopituitarism and isolated ACTH deficiency syndrome, and 3 with Sheehan's syndrome), APA in their sera were investigated. Seven out of 16 members (44%) showed positive APA. Among 6 first-degree relatives of 16 family members, both or either one of APA and PCSA were positive in 4 (67%). Out of 10 of their second- or third-degree relatives, 3 (30%) were positive for PCA or PCSA. All of 3 relatives with positive APA studied showed mild pituitary hypofunction without any clinical manifestations.(ABSTRACT TRUNCATED AT 400 WORDS)