Pituitary autoimmunity is associated with hypopituitarism in patients with primary empty sella.

OBJECTIVE: Some evidence suggests that late stage autoimmune hypophysitis (AH) may result in empty sella (ES). Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) and their correlation with pituitary function in patients with ES. DESIGN: In this casecontrol study 85 patients with primary ES, 16 patients with ES secondary to head trauma, 214 healthy controls, and 16 AH were enrolled in a tertiary referral center. METHODS: PitAb were assessed in all cases and controls. Endocrine function was assessed by basal hormone measurement and dynamic testing in all ES cases. RESULTS: PitAb prevalence was higher in primary ES (6%) than in healthy subjects (0.5% p=0.003) and lower than in AH patients (50%, p<0.0001). PitAb were not found in patients with secondary ES. Hypopituitarism was found in 49% of primary ES and in 62% of secondary ES (p=0.34). A positive correlation between the presence of PitAb and hypopituitarism was found in primary ES (p=0.02). CONCLUSIONS: The significant association between pituitary autoimmunity and hypopituitarism suggests that ES, in selected cases, could be the final result of AH.

Anti-hypothalamus and anti-pituitary antibodies may contribute to perpetuate the hypopituitarism in patients with Sheehan's syndrome.

OBJECTIVE: While anti-pituitary antibodies (APAs) were detected in some patients with Sheehan's syndrome (SS) suggesting an autoimmune pituitary involvement in the development of their hypopituitarism, hypothalamic cell anti-hypothalamus antibodies (AHAs) have not been investigated so far. DESIGN: The aim of this study was to evaluate the presence of AHA and APA in SS patients to verify whether an autoimmune hypothalamic-pituitary process can contribute to their late hypopituitarism. METHODS: Twenty women with SS with a duration of disease ranging from 3 to 40 years (median 25.5 years) were enrolled into the study. Out of 20 patients, 12 (60%) had panhypopituitarism and the others had partial hypopituitarism well corrected with appropriate replacement therapy. None of them had clinical central diabetes insipidus. AHA and APA were investigated by immunofluorescence method in all patients. In addition, a four-layer immunofluorescence method was used to verify whether AHA immunostained vasopressin-secreting cells (AVP-c) or not. RESULTS: AHAs were found in 8 out of 20 (40%) and APAs in 7 out of 20 (35%) patients with titers ranging from 1:32 to 1:128 and 1:16 to 1:32 respectively; however, in none of these positive patients AHA immunostained vasopressin cells. None of controls resulted positive for both antibodies. CONCLUSIONS: Patients with SS, even many years after the onset of SS, can show antibodies to pituitary and/or hypothalamic but not AVP-secreting cells. Antibodies to unknown hypothalamic cells (releasing factor-secreting cells) other than APAs suggest that an autoimmune process involving both the hypothalamus and pituitary gland may contribute to late pituitary dysfunction in SS patients.

No evidence for autoimmunity as a major cause of the empty sella syndrome.

OBJECTIVE: The cause of empty sella syndrome (ESS) remains largely unknown. We measured eleven organ-specific autoantibodies in serum in order to evaluate possible autoimmune components in ESS. PATIENTS: Thirty patients with ESS and 50 healthy blood donors participated in the study. MEASUREMENTS: Detection of pituitary autoantibodies was performed by immunoblotting with human pituitary cytosol as antigen. Thyroid peroxidase (TPO) and TSH receptor (TRAK) autoantibodies were analysed by radioimmunoassay. The remaining eight autoantibodies were detected by in vitro transcription and translation of the autoantigens and immunoprecipitation. RESULTS: The majority of the ESS patients (18/30) exhibited no immunoreactivity at all. None of the remaining 12 ESS patients reacted against more than one autoantigen. No immunoreactivity was found more frequently among ESS patients than healthy blood donors. Pituitary autoantibodies were not correlated to the ESS patients' pituitary function or sellar size, although the results indicated a tendency of increased autoimmunity in patients with hypopituitarism and normal sella size respectively. CONCLUSION: Detection of autoantibodies is a valuable tool in the diagnostic work-up of autoimmune diseases. By analysing a large number of organ-specific autoantibodies we found no evidence of ESS being associated with any specific autoimmune disease. The pathogenesis of ESS is believed to be heterogeneous and our findings suggest autoimmune components to be of minor importance. In some selective cases, ESS in combination with hypopituitarism may be the result of an autoimmune disease in the pituitary gland but this needs further investigation.

Association of arginine vasopressin-secreting cell, steroid-secreting cell, adrenal and islet cell antibodies in a patient presenting with central diabetes insipidus, empty sella, subclinical adrenocortical failure and impaired glucose tolerance.

A 36-year-old woman with central diabetes insipidus (DI), diagnosed when she was 7, was referred to our Endocrine Unit in January 1993 for further hormonal investigations. Clinical and laboratory findings confirmed the diagnosis of central DI. Cranial computed tomography and magnetic resonance imaging showed only an empty sella. Moreover, we noted impaired glucose tolerance and unusual findings of subclinical adrenocortical failure, i.e. high plasma renin activity with normal aldosterone levels, high ACTH despite normal basal and ACTH-stimulated cortisol levels. Immunological study of the patient's serum showed the presence of arginine vasopressin (AVP)-secreting cell antibodies (Abs), steroid-producing cell Abs, adrenal and islet cell Abs. The following aspects of our case are stressed and discussed: (1) the presence of AVP-secreting cell Abs 29 years after the diagnosis of DI; (2) the association between DI, empty sella and subclinical autoimmune adrenocortical failure with unusual hormonal findings, and (3) impaired glucose tolerance with islet cell antibody positivity.

Presence of anti-pituitary hormone antibodies in patients with empty sella syndrome and pituitary tumours.

OBJECTIVE: We evaluated the presence of anti-pituitary hormone autoantibodies (APHA) in patients with primary empty sella syndrome and pituitary tumours and examined the correlation of positive antibodies with the hormonal deficiencies. DESIGN: Case-control, retrospective study. PATIENTS: Eleven patients were identified with primary empty sella syndrome or a pituitary tumour by magnetic resonance imaging or computed tomography scanning. Six healthy, normal subjects without evidence of a pituitary problem served as the control group. MEASUREMENTS: Anti-pituitary hormone autoantibodies against purified pituitary hormones were measured in all subjects utilizing an immunoblotting technique. All patients with pituitary disease had their medical records reviewed for any hormonal evaluation. RESULTS: All of the normal subjects were negative for antipituitary hormone antibodies. Forty-five per cent of patients with pituitary disease (pituitary tumours or primary empty sella syndrome) had positive antipitutary hormone antibodies. Of the five patients with positive antipituitary hormone antibodies, anti-ACTH antibodies were the most common (5/5) followed by anti-TSH and anti-GH antibodies (2/5 for each). The hormonal deficiencies failed to correspond with the antipituitary hormone antibodies. Anti-ACTH antibody had a sensitivity of 50% with a specificity of 56%. The anti-TSH antibody yielded a sensitivity of 67% with a specificity of 100%. The anti-FSH/LH antibody reported a 0% sensitivity. CONCLUSIONS: Detection of antipituitary hormone antibody was unable to discriminate between empty sella syndrome and pituitary tumours. The presence of these antipituitary hormone antibodies were neither specific for, nor predictive of, the endocrine deficiencies.

[A case of Hashimoto's thyroiditis associated with renal tubular acidosis, Sjögren syndrome and empty sella syndrome].

This report describes a 48-year old female patient with Hashimoto's thyroiditis, distal-type renal tubular acidosis (d-RTA), Sjögren syndrome (SjS), and empty sella syndrome (ESS). She has been receiving replacement of thyroxine for Hashimoto's thyroiditis since 1967. She felt muscle weakness and numbness in the extremities and was found to have low serum potassium (2.9 mEq/l) in 1987. Since then she has been administrated potassium chloride orally. She was admitted to our hospital because of recurrence of muscle weakness and numbness of the extremities in November 1990. Laboratory examination revealed that her serum levels of antimicrosomal antibody and anti-thyroglobulin antibody were highly positive (MCHA: x 2(10) x 100, and TGHA: x 100). Furthermore, she was revealed to have 1) d-RTA by oral tolerance tests with the administration of NH4Cl and NaHCO3, 2) SjS by Schirmer test and sialography, and 3) ESS by computed tomography and magnetic resonance imaging examinations of the pituitary. Association of Hashimoto's thyroiditis, d-RTA, SjS and ESS in this case may possibly be caused by common autoimmune mechanism.

A case of autoimmune insulin antibody syndrome associated with polymyositis, empty sella and apparent high urinary output of immunoreactive insulin.

Patients with autoimmune insulin antibody are characterized by hypoglycemic attacks and antibodies to insulin in serum without prior insulin administration. In the present report, a patient with hypoglycemia due to autoimmune insulin antibody associated with primary empty sella syndrome and polymyositis appeared to have high urinary immunoreactive insulin (IRI) in the face of normal urinary C peptide. Consequently, the urinary IRI/C peptide ratio was apparently high. The amelioration of hypoglycemic attacks and polymyositis by prednisolone treatment was accompanied by the disappearance of the antibodies and complete normalization of the urinary IRI and IRI/C peptide ratio. No comparable rise in the urinary IRI and IRI/C peptide ratio was observed in the patients with other disorders studied. Glucose clamp and glucose tolerance study showed decreased sensitivity to exogenous or newly secreted insulin, prolonged half disappearance time of serum insulin, and normal disappearance of blood glucose. These results were consistent with the idea that autoantibodies buffered the effect of exogenous or newly secreted insulin and maintained a relatively constant level of serum free insulin which was not high enough when a large amount of glucose was loaded, but was too high after prolonged fasting, which eventually caused hypoglycemic attacks.

Antipituitary antibodies in patients with the primary empty sella syndrome.

The frequency of detection of serum antibodies against pituitary cells was determined in 32 patients with the primary empty sella syndrome. Antibodies reacting with corticotropin-secreting mouse AtT20 and PRL-secreting rat GH3 cells were found in 24 (75%) and 15 (47%), respectively, of the 32 patients; 14 patients (44%) had antibodies reacting with both cell lines. In patients with pituitary adenomas, the prevalence of antipituitary antibodies was significantly lower than in those with the empty sella syndrome; 1 of 9 acromegalic patients had antibodies reacting with GH3 cells, and 2 of 9 prolactinoma patients and 1 of 7 patients with nonfunctioning adenomas had antibodies reacting with both AtT20 and GH3 cells. Among 6 patients with idiopathic diabetes insipidus, 1 patient had antibodies reacting with AtT20 and GH3 cells, and 2 patients had antibodies reacting with either AtT20 or GH3 cells. None of 5 patients with established autoimmune diseases (3 with systemic lupus erythematosus and 2 with autoimmune adrenal failure) had antipituitary antibodies in their serum. These results suggest that pituitary antibodies may be related to the development of pituitary atrophy and the primary empty sella syndrome, and that the test may be clinically useful as a screening test for the empty sella syndrome.

Primary empty sella: a histologic and immunocytologic study.

A primary "empty" sella turcica was found incidentally at autopsy, and the anterior lobe of the pituitary gland was studied with the immunoperoxidase technique. All five adenohypophysial cell types, ie, somatotrophs, lactotrophs, corticotrophs, thyrotrophs, and gonadotrophs (containing follicle-stimulating hormone [FSH] and luteinizing hormone [LH], were present in adequate numbers and were well granulated, indicating normal hormone storage.