Antipituitary Antibodies in Patients with Lymphocytic Hypophysitis

Abstract

Background: Lymphocytic hypophysitis is one of the causes of hypopituitarism, which is considered an autoimmune reaction in the anterior pituitary. Method: We examined antipituitary antibodies in patients with lymphocytic hypophysitis and related diseases by immunoblotting method. Results: Autoantibodies to a 22-kDa human pituitary cytosolic protein were identified in significantly higher frequencies in sera from patients with lymphocytic hypophysitis (11 of 15, 73.3%) and isolated ACTH deficiency (7 of 9, 77.8%) compared with Hashimoto thyroiditis, Basedow’s disease and normal control subjects. Also, reactivity against a 49-kDa human pituitary cytosolic protein was seen in 6 of 15 patients (40%) with lymphocytic hypophysitis. N-terminal amino acid sequences of 22-kDa human and rat pituitary cytosolic protein were FPTIPLSVL and FPAMPLSSLFAN, respectively, suggesting that they are human and rat growth hormone, respectively. The pituitary dysfunction (at least one hormone dysfunction) was observed in 11 of 14 patients. Nine of them (82%) showed 22 kDa antibody but 2 of them (18%) did not. Conclusion: The present study demonstrated that pituitary autoantibodies could be involved in the pathogenesis of lymphocytic hypophysitis and could be a positive marker for the disease.

Longitudinal Study of Patients with Idiopathic Isolated TSH Deficiency: Possible Progression of Pituitary Dysfunction in Lymphocytic Adenohypophysitis

“…APAs are often detected in several pituitary diseases [1][2][3]. However, it is unclear whether the detected APAs are related to the etiology or are consequences of the disease.…”

“…In our previous report [1], APA, the antibody to the human pituitary cytosol was detected in five of six patients with isolated TSH deficiency. APAs were detected also in patients with isolated ACTH deficiency [2,4,34,35] and empty sella [34,35]. It is suggested that LAH as an autoimmune disease contributed to the etiology of isolated TSH deficiency in some of the patients.…”

“…It is suggested that LAH as an autoimmune disease contributed to the etiology of isolated TSH deficiency in some of the patients. The antibodies to 22-Kd [4] or 49-Kd [2,5] protein of human pituitary gland were detected in patients with LAH. The antibody to α-enolase, which is a ubiquitous glycolytic enzyme, was frequently detected in the patients with LAH [3,6], but it was frequently detected in patients with pituitary macroadenoma or other autoimmune diseases [3] as well.…”

“…Patients with idiopathic isolated TSH deficiency sometimes show the presence of anti-pituitary antibody (APA) [1][2][3] and empty sella on magnetic resonance imaging (MRI) [1].…”

“…Patients with lymphocytic adenohypophysitis (LAH) frequently demonstrate the presence of APAs [2][3][4][5][6] and hypopituitarism to a variable degree [7][8][9][10][11][12]. To our knowledge, however, only one patient with isolated TSH deficiency associated with LAH has been reported [13].…”