Aberrant CD8+T cells drive reproductive dysfunction in female mice with elevated IFN-γ levels

Introduction

Interferon-gamma (IFN-γ) is pivotal in orchestrating immune responses during healthy pregnancy. However, its dysregulation, often due to autoimmunity, infections, or chronic inflammatory conditions, is implicated in adverse reproductive outcomes such as pregnancy failure or infertility. Additionally, the underlying immunological mechanisms remain elusive.

Methods

Here, we explore the impact of systemic IFN-γ elevation on cytotoxic T cell responses in female reproduction utilizing a systemic lupus-prone mouse model with impaired IFN-γ degradation.

Results

Our findings reveal that heightened IFN-γ levels triggered the infiltration of CD8+T cells in the pituitary gland and female reproductive tract (FRT), resulting in prolactin deficiency and subsequent infertility. Furthermore, we demonstrate that chronic IFN-γ elevation increases effector memory CD8+T cells in the murine ovary and uterus.

Discussion

These insights broaden our understanding of the role of elevated IFN-γ in female reproductive dysfunction and suggest CD8+T cells as potential immunotherapeutic targets in female reproductive disorders associated with chronic systemic IFN-γ elevation.

Assessment of Neuroendocrine Changes and Hypothalamo-Pituitary Autoimmunity in Patients with COVID-19

SARS-CoV-2 may affect the hypothalamic-pituitary axis and pituitary dysfunction may occur. Therefore, we investigated neuroendocrine changes, in particular, secondary adrenal insufficiency, using a dynamic test and the role of autoimmunity in pituitary dysfunction in patients with COVID-19. The single-center, prospective, case-control study included patients with polymerase chain reaction (PCR)-confirmed COVID-19 and healthy controls. Basal hormone levels were measured, and the adrenocorticotropic hormone (ACTH) stimulation test was performed. Antipituitary (APA) and antihypothalamic antibodies (AHA) were also determined. We examined a total of 49 patients with COVID-19 and 28 healthy controls. The frequency of adrenal insufficiency in patients with COVID-19 was found as 8.2%. Patients with COVID-19 had lower free T₃, IGF-1, and total testosterone levels, and higher cortisol and prolactin levels when compared with controls. We also demonstrated the presence of APA in three and AHA in one of four patients with adrenal insufficiency. In conclusion, COVID-19 may result in adrenal insufficiency, thus routine screening of adrenal functions in these patients is needed. Endocrine disturbances in COVID-19 are similar to those seen in acute stressful conditions or infections. Pituitary or hypothalamic autoimmunity may play a role in neuroendocrine abnormalities in COVID-19.

Hypophysitis, the Growing Spectrum of a Rare Pituitary Disease

Hypophysitis is defined as inflammation of the pituitary gland that is primary or secondary to a local or systemic process. Differential diagnosis is broad (including primary tumors, metastases, and lympho-proliferative diseases) and multifaceted. Patients with hypophysitis typically present with headaches, some degree of anterior and/or posterior pituitary dysfunction, and enlargement of pituitary gland and/or stalk, as determined by imaging. Most hypophysitis causes are autoimmune, but other etiologies include inflammation secondary to sellar tumors or cysts, systemic diseases, and infection or drug-induced causes. Novel pathologies such as immunoglobulin G4-related hypophysitis, immunotherapy-induced hypophysitis, and paraneoplastic pituitary-directed autoimmunity are also included in a growing spectrum of this rare pituitary disease. Typical magnetic resonance imaging reveals stalk thickening and homogenous enlargement of the pituitary gland; however, imaging is not always specific. Diagnosis can be challenging, and ultimately, only a pituitary biopsy can confirm hypophysitis type and rule out other etiologies. A presumptive diagnosis can be made often without biopsy. Detailed history and clinical examination are essential, notably for signs of underlying etiology with systemic manifestations. Hormone replacement and, in selected cases, careful observation is advised with imaging follow-up. High-dose glucocorticoids are initiated mainly to help reduce mass effect. A response may be observed in all auto-immune etiologies, as well as in lymphoproliferative diseases, and, as such, should not be used for differential diagnosis. Surgery may be necessary in some cases to relieve mass effect and allow a definite diagnosis. Immunosuppressive therapy and radiation are sometimes also necessary in resistant cases.

Cytokines-Biogenesis and Their Role in Human Breast Milk and Determination

Cytokines play a huge role in many biological processes. Their production, release and interactions are subject to a very complex mechanism. Cytokines are produced by all types of cells, they function very differently and they are characterized by synergism in action, antagonism, and aggregation activity, opposing action of one cytokine, overlapping activity, induction of another cytokine, inhibition of cytokine synthesis at the mRNA level as well as autoregulation-stimulation or inhibition of own production. The predominance of pro-inflammatory cytokines leads to a systemic inflammatory response, and anti-inflammatory-to an anti-inflammatory response. They regulate the organism's immune response and protect it against sudden disturbances in homeostasis. The synthesis and activity of cytokines are influenced by the central nervous system through the endocrine system (pituitary gland, adrenal glands).

Anti-pituitary antibodies as a marker of autoimmunity in pituitary glands

Autoimmunity contributes to the pathogenesis of hypophysitis, a chronic inflammatory disease in the pituitary gland. Although primary hypophysitis is rare, the number of pituitary dysfunction cases induced by immune checkpoint inhibitors (ICIs) is increasing. While it is difficult to prove the involvement of autoimmunity in the pituitary glands, circulating anti-pituitary antibodies (APAs) can be measured by indirect immunofluorescence and used as a surrogate marker of pituitary autoimmunity. APAs are present in several pituitary diseases, including lymphocytic adenohypophysitis, lymphocytic infundibulo-neurohypophysitis (LINH), IgG4-related hypophysitis, and pituitary dysfunction induced by ICIs. Mass spectrometry analysis of antigens targeted by APAs clarified rabphilin-3A as an autoantigen in LINH. This demonstrates that APAs can be applied as a probe to identify novel autoantigens in other pituitary autoimmune diseases, including pituitary dysfunction induced by ICIs, which can aid in biomarker discovery.

Immune Landscape of Pituitary Tumors Reveals Association Between Macrophages and Gonadotroph Tumor Invasion

PURPOSE

Pituitary neuroendocrine tumors (PitNETs) are frequent intracranial neoplasms that present heterogenic characteristics. Little is known about the immune cell network that exists in PitNETs and its contribution to their aggressive behavior.

METHODS

Here we combined flow cytometry, t-SNE analysis, and histological approaches to define the immune landscape of surgically resected PitNETs. Xenografts of rodent pituitary tumor cells and resected PitNETs were performed in Rag2KO mice, in combination with in vitro analysis aimed at dissecting the role of pituitary tumor-cells in monocyte recruitment.

RESULTS

We report that gonadotroph PitNETs present an increased CD68+ macrophage signature compared to somatotroph, lactotroph, and corticotroph PitNETs. Transcriptomic and histological characterizations confirmed gonadotroph infiltrating macrophages expressed CD163, MRC-1, ARG1, and CSF1R M2 macrophage markers. Use of growth hormone (GH)3/GH4 somatotroph and LβT2/αT3.1 gonadotroph cells drove THP1 macrophage migration through respective expression of CCL5 or CSF1. Although both LβT2 and GH3 cells recruited F4/80 macrophages following their engraftment in mice, only LβT2 gonadotroph cells showed a capacity for M2-like polarization. Similar observations were performed on patient-derived xenografts from somatotroph and gonadotroph tumors. Analysis of clinical data further demonstrated a significant correlation between the percentage of CD68+ and CD163+ infiltrating macrophages and the invasive character of gonadotroph tumors.

CONCLUSIONS

Gonadotroph tumor drive the recruitment of macrophages and their subsequent polarization to an M2-like phenotype. More importantly, the association between infiltrating CD68+/CD163+ macrophages and the invasiveness of gonadotroph tumors points to macrophage-targeted immunotherapies being a potent strategy to limit the progression of gonadotroph PitNETs.

Impact of Pituitary Autoimmunity and Genetic Disorders on Growth Hormone Deficiency in Children and Adults

Growth hormone (GH), mostly through its peripheral mediator, the insulin-like growth factor 1(IGF1), in addition to carrying out its fundamental action to promote linear bone growth, plays an important role throughout life in the regulation of intermediate metabolism, trophism and function of various organs, especially the cardiovascular, muscular and skeletal systems. Therefore, if a prepubertal GH secretory deficiency (GHD) is responsible for short stature, then a deficiency in adulthood identifies a nosographic picture classified as adult GHD syndrome, which is characterized by heart, muscle, bone, metabolic and psychic abnormalities. A GHD may occur in patients with pituitary autoimmunity; moreover, GHD may also be one of the features of some genetic syndromes in association with other neurological, somatic and immune alterations. This review will discuss the impact of pituitary autoimmunity on GHD and the occurrence of GHD in the context of some genetic disorders. Moreover, we will discuss some genetic alterations that cause GH and IGF-1 insensitivity and the arguments in favor and against the influence of GH/IGF-1 on longevity and cancer in the light of the papers on these issues that so far appear in the literature.

Antibodies Against Hypothalamus and Pituitary Gland in Childhood-Onset Brain Tumors and Pituitary Dysfunction

Purpose: To detect the presence of antipituitary (APA) and antihypothalamus antibodies (AHA) in subjects treated for brain cancers, and to evaluate their potential association with pituitary dysfunction. Methods: We evaluated 63 patients with craniopharyngioma, glioma, and germinoma treated with surgery and/or radiotherapy and/or chemotherapy at a median age of 13 years. Forty-one had multiple pituitary hormone deficiencies (MPHD), six had a single pituitary defect. GH was the most common defect (65.1%), followed by AVP (61.9%), TSH (57.1%), ACTH (49.2%), and gonadotropin (38.1%). APA and AHA were evaluated by simple indirect immunofluorescence method indirect immunofluorescence in patients and in 50 healthy controls. Results: Circulating APA and/or AHA were found in 31 subjects (49.2%) and in none of the healthy controls. In particular, 25 subjects out of 31 were APA (80.6%), 26 were AHA (83.90%), and 20 were both APA and AHA (64.5%). Nine patients APA and/or AHA have craniopharyngioma (29%), seven (22.6%) have glioma, and 15 (48.4%) have germinoma. Patients with craniopharyngioma were positive for at least one antibody in 39.1% compared to 33.3% of patients with glioma and to 78.9% of those with germinoma with an analogous distribution for APA and AHA between the three tumors. The presence of APA or AHA and of both APA and AHA was significantly increased in patients with germinoma. The presence of APA (P = 0.001) and their titers (P = 0.001) was significantly associated with the type of tumor in the following order: germinomas, craniopharyngiomas, and gliomas; an analogous distribution was observed for the presence of AHA (P = 0.002) and their titers (P = 0.012). In addition, we found a significant association between radiotherapy and APA (P = 0.03). Conclusions: Brain tumors especially germinoma are associated with the development of hypothalamic-pituitary antibodies and pituitary defects. The correct interpretation of APA/AHA antibodies is essential to avoid a misdiagnosis of an autoimmune infundibulo-neurohypophysitis or pituitary hypophysitis in patients with germinoma.

Effects of long-term crowding stress on neuro-endocrine-immune network of rainbow trout (Oncorhynchus mykiss)

Low levels of stresses cause eustress while high stressful situations result in distress. Female rainbow trout (Oncorhynchus mykiss) was reared under crowded conditions to mimic the stressful environment of intensive fishery production. Trout was stocked for 300 days with initial densities of 4.6 ± 0.02 (final: 31.1 ± 0.62), 6.6 ± 0.03 (final: 40.6 ± 0.77), and 8.6 ± 0.04 (final: 49.3 ± 1.09) kg/m³ as SD1, SD2 and SD3. We assessed molecular, cellular and organismal parameters to understand the flexibility of neuro-endocrine-immune network during stress. Trout with higher initial density (SD3) displayed the slightly activated hypothalamus-pituitary-interrenal (HPI) axis with positively increased antioxidant enzyme activities and anti-inflammatory cytokine transcriptions on day 60 or 120. These results indicated that low level of stress was capable of exerting eustress by activating neuro-endocrine-immune network with beneficial adaptation. Transition from eustress to distress was induced by the increased intensity and duration of crowding stress on day 240 and 300. The prolonged activation of HPI axis resulted in suppressed growth hormone-insulin-like growth factor (GH-IGF) axis, up-regulated cytokine transcriptions and severe reactive oxygen species stress. Stress means reset of neuro-endocrine-immune network with energy expenditure and redistribution. Digestive ability of trout with distress was also inhibited on day 240 and 300, indicating a decreased total energy supplement and energy distribution for functions are not necessary for surviving such as growth and reproduction. Consequently, we observed the dyshomeostasis of energy balance and neuro-endocrine-immune network of trout during long-term crowding conditions.

The role of autoimmunity in pituitary dysfunction due to traumatic brain injury

PURPOSE

Traumatic brain injury (TBI) is one of the most common causes of mortality and long-term disability and it is associated with an increased prevalence of neuroendocrine dysfunctions. Post-traumatic hypopituitarism (PTHP) results in major physical, psychological and social consequences leading to impaired quality of life. PTHP can occur at any time after traumatic event, evolving through various ways and degrees of deficit, requiring appropriate screening for early detection and treatment. Although the PTHP pathophysiology remains to be elucitated, on the basis of proposed hypotheses it seems to be the result of combined pathological processes, with a possible role played by hypothalamic-pituitary autoimmunity (HPA). This review is aimed at focusing on this possible role in the development of PTHP and its potential clinical consequences, on the basis of the data so far appeared in the literature and of some results of personal studies on this issue.

METHODS

Scrutinizing the data so far appeared in literature on this topic, we have found only few studies evaluating the autoimmune pattern in affected patients, searching in particular for antipituitary and antihypothalamus autoantibodies (APA and AHA, respectively) by simple indirect immunofluorescence.

RESULTS

The presence of APA and/or AHA at high titers was associated with an increased risk of onset/persistence of PTHP.

CONCLUSIONS

HPA seems to contribute to TBI-induced pituitary damage and related PTHP. However, further prospective studies in a larger cohort of patients are needed to define etiopathogenic and diagnostic role of APA/AHA in development of post-traumatic hypothalamic/pituitary dysfunctions after a TBI.

Fish pituitary show an active immune response after in vitro stimulation with Vibrio bacterin

The pituitary is a central organ of the neuro-endocrine system in fish that plays critical roles in various physiological processes, including stress response and behavior. Although it is known that pituitary hormones can have a direct or indirect influence stimulating or suppressing the immune responses, whether there is a local immune response in the pituitary or what is the effect of the immune stimulus on the pituitary function in fish is unknown. With the aim to understand the interaction between the immune responses and the endocrine axes at the pituitary level, particularly the Hypothalamus-Pituitary-Interrenal (HPI) axis, pituitaries of rainbow trout (Oncorhynchus mykiss) were cultured in vitro, incubated with bacterin, or bacterin plus CRH, cortisol, human recombinant IL1β, or spleen medium for 3 h, and then genes involved in pro-inflammation (il1β, il8, tnfα1, ifnγ), anti-inflammation (tgfβ1b, il10), immune modulation (mhcIIa, c3, mif) and stress response (crhbp, pomca, pomcb, gr1) were tested. Data showed that, incubation with bacterin alone and bacterin plus recombinant IL1β or CRH, as well as medium from bacterin treated spleen caused significant up-regulation of pro-inflammatory genes il1β and il8, while down-regulated the anti-inflammatory gene tgfβ1b. Besides, recombinant IL1β plus bacterin or alone caused raise of mhcIIa and tnfa, respectively. On the contrary, just a slight or even no alteration was recorded in the expression of stress response genes including crhbp, pomca, pomcb and gr1 in the in vitro cultured trout pituitary following this stimulation. These results suggest a local immune gene equipment in the pituitary of fish, and the potential for fish pituitary to develop both innate and adaptive immune responses, whereas that immune stimulation was not able to evoke a significant endocrine stress response in vitro.

New causes of hypophysitis

Hypophysitis is a rare entity characterized by inflammation of the pituitary gland and its stalk that can cause hypopituitarism and/or mass effect. Etiology can be categorized as primary or secondary to systemic disease, but may also be classified according to anatomical and hispathological criteria. Newly recognized causes of hypophysits have been described, mainly secondary to immunomodulatory medications and IgG4-related disease. Diagnosis is based on clinical, laboratory and imaging data, whereas pituitary biopsy, though rarely indicated, may provide a definitive histological diagnosis. For the clinician, obtaining a broad clinical and drug history, and performing a thorough physical examination is essential. Management of hypophysitis includes hormone replacement therapy if hypopituitarism is present and control of the consequences of the inflammatory pituitary mass (e.g. compression of the optic chiasm) using high-dose glucocorticoids, whereas pituitary surgery is reserved for those unresponsive to medical therapy and/or have progressive disease. However, there remains an unmet need for controlled studies to inform clinical practice.

Autoimmune pituitary involvement in Prader-Willi syndrome: new perspective for further research

The role of antipituitary antibodies in the pathophysiology of pituitary hormone deficiency has been increasingly elucidated over the last decade. Prader-Willi syndrome is a genetic disorder which includes hypothalamic/pituitary dysfunction as one of its main features. We looked for autoimmune pituitary involvement in 55 adults with Prader-Willi syndrome, discovering that about 30% of them have a positive titer of antipituitary antibodies. Although the presence of these autoantibodies could only be an "epiphenomenon", our results suggest that autoimmune mechanisms might contribute, at least in part, to the pituitary impairment of Prader-Willi syndrome, and in addition to genetically determined dysfunction of the central nervous system. This paper provides a new perspective on pituitary impairment in these patients, suggesting that the search for hypophisitis could be a reasonable and interesting field for further research.

MECHANISMS IN ENDOCRINOLOGY: Hypophysitis: diagnosis and treatment

Hypophysitis is a rare condition characterised by inflammation of the pituitary gland, usually resulting in hypopituitarism and pituitary enlargement. Pituitary inflammation can occur as a primary hypophysitis (most commonly lymphocytic, granulomatous or xanthomatous disease) or as secondary hypophysitis (as a result of systemic diseases, immunotherapy or alternative sella-based pathologies). Hypophysitis can be classified using anatomical, histopathological and aetiological criteria. Non-invasive diagnosis of hypophysitis remains elusive, and the use of currently available serum anti-pituitary antibodies are limited by low sensitivity and specificity. Newer serum markers such as anti-rabphilin 3A are yet to show consistent diagnostic value and are not yet commercially available. Traditionally considered a very rare condition, the recent recognition of IgG4-related disease and hypophysitis as a consequence of use of immune modulatory therapy has resulted in increased understanding of the pathophysiology of hypophysitis. Modern imaging techniques, histological classification and immune profiling are improving the accuracy of the diagnosis of the patient with hypophysitis. The objective of this review is to bring readers up-to-date with current understanding of conditions presenting as hypophysitis, focussing on recent advances and areas for future development. We describe the presenting features, investigation and diagnostic approach of the patient with likely hypophysitis, including existing conventional techniques and those in the research/development arena. Hypophysitis usually results in acute and persistent pituitary hormone deficiency requiring long-term replacement. Management of hypophysitis includes control of the inflammatory pituitary mass using a variety of treatment strategies including surgery and medical therapy. Glucocorticoids remain the mainstay of medical treatment but other immunosuppressive agents (e.g. azathioprine, rituximab) show benefit in some cases, but there is a need for controlled studies to inform practice.

Two types of rat pituitary somatotrophs secrete growth hormone with different biological and immunological profiles

OBJECTIVE

Two stable subpopulations of somatotrophs reside in the rat pituitary gland. We tested the hypothesis that one produced growth hormone (GH) with greater activity when tested in the tibial line bioassay (BGH) than the other, while differences in the activities between the two groups would be less dramatic when measured by immunoassay (IGH).

DESIGN

A series of studies using hypophysectomized rats, hollow fibers, treatments and culture models were used to differentiate differences in Type I and Type II anterior pituitary somatotrophs in both function and production of immunoactive and bioactive growth hormone.

RESULTS

We found that dense, Type II somatotrophs (>1.070g·cm^-3) differed markedly in their secretion patterns of IGH vs BGH in different In vitro and in vivo tests. In culture, Type II cells secreted five times as much BGH, and three fourths as much IGH as the less dense Type I cells. Production (storage and secretion) of BGH was 7-fold greater by Type II cells whereas IGH production was identical for the two cell types. Implantation of Type II cells into hypophysectomized rats significantly increased body weight, epiphyseal cartilage thickness, and muscle weight of the recipients; in contrast, Type I cells elicited only a small increase in body weight. Type I somatotrophs isolated from rats which had been previously fasted or insulin-treated subsequently showed only small, inconsistent changes in release relative to that from cells in the unfractionated cell population. However, release of BGH from the Type II cells was markedly decreased.

CONCLUSION

Both IGH and BGH should be considered in the elucidation of GH physiology.

Anti-pituitary antibodies against corticotrophs in IgG4-related hypophysitis

PURPOSE

IgG4-related disease is a systemic inflammatory disease characterized by infiltration of IgG4-positive plasma cells into multiple organs, including the pituitary gland. Autoimmunity is thought to be involved in the pathogenesis of IgG4-related disease. The diagnosis of IgG4-related hypophysitis (IgG4-RH) is difficult because its clinical features, such as pituitary swelling and hypopituitarism, are similar to those of other pituitary diseases, including lymphocytic hypophysitis and sellar/suprasellar tumors. The presence and significance of anti-pituitary antibodies (APA) in IgG4-RH is unclear.

METHODS

In this case-control study, we used single indirect immunofluorescence on human pituitary substrates to assess the prevalence of serum APA in 17 patients with IgG4-RH, 8 control patients with other pituitary diseases (lymphocytic infundibulo-neurohypophysitis, 3; craniopharyngioma, 2; germinoma, 3), and 9 healthy subjects. We further analyzed the endocrine cells targeted by the antibodies using double indirect immunofluorescence.

RESULTS

APA were found in 5 of 17 patients with IgG4-RH (29%), and in none of the pituitary controls or healthy subjects. The endocrine cells targeted by the antibodies in the 5 IgG4-RH cases were exclusively corticotrophs. Antibodies were of the IgG1 subclass, rather than IgG4, in all 5 cases, suggesting that IgG4 is not directly involved in the pathogenesis. Finally, antibodies recognized pro-opiomelanocortin in 2 of the cases.

CONCLUSIONS

Our study suggests that autoimmunity is involved in the pathogenesis of IgG4-RH and that corticotrophs are the main antigenic target, highlighting a possible new diagnostic marker for this condition.

In Situ Activation of Pituitary-Infiltrating T Lymphocytes in Autoimmune Hypophysitis

Autoimmune hypophysitis (AH) is a chronic inflammatory disease characterized by infiltration of T and B lymphocytes in the pituitary gland. The mechanisms through which infiltrating lymphocytes cause disease remain unknown. Using a mouse model of AH we assessed whether T lymphocytes undergo activation in the pituitary gland. Infiltrating T cells co-localized with dendritic cells in the pituitary and produced increased levels of interferon-γ and interleukin-17 upon stimulation in vitro. Assessing proliferation of CD3- and B220-postive lymphocytes by double immunohistochemistry (PCNA-staining) and flow cytometry (BrdU incorporation) revealed that a discrete proportion of infiltrating T cells and B cells underwent proliferation within the pituitary parenchyma. This proliferation persisted into the late disease stage (day 56 post-immunization), indicating the presence of a continuous generation of autoreactive T and B cells within the pituitary gland. T cell proliferation in the pituitary was confirmed in patients affected by autoimmune hypophysitis. In conclusion, we show that pituitary-infiltrating lymphocytes proliferate in situ during AH, providing a previously unknown pathogenic mechanism and new avenues for treatment.

Hypophysitis Secondary to Cytotoxic T-Lymphocyte-Associated Protein 4 Blockade: Insights into Pathogenesis from an Autopsy Series

Hypophysitis that develops in cancer patients treated with monoclonal antibodies blocking cytotoxic T-lymphocyte-associated protein 4 (CTLA-4; an inhibitory molecule classically expressed on T cells) is now reported at an incidence of approximately 10%. Its pathogenesis is unknown, in part because no pathologic examination of the pituitary gland has been reported to date. We analyzed at autopsy the pituitary glands of six cancer patients treated with CTLA-4 blockade, one with clinical and pathologic evidence of hypophysitis, one with mild lymphocytic infiltration in the pituitary gland but no clinical signs of hypophysitis, and four with normal pituitary structure and function. CTLA-4 antigen was expressed by pituitary endocrine cells in all patients but at different levels. The highest levels were found in the patient who had clinical and pathologic evidence of severe hypophysitis. This high pituitary CTLA-4 expression was associated with T-cell infiltration and IgG-dependent complement fixation and phagocytosis, immune reactions that induced an extensive destruction of the adenohypophyseal architecture. Pituitary CTLA-4 expression was confirmed in a validation group of 37 surgical pituitary adenomas and 11 normal pituitary glands. The study suggests that administration of CTLA-4 blocking antibodies to patients who express high levels of CTLA-4 antigen in the pituitary can cause an aggressive (necrotizing) form of hypophysitis through type IV (T-cell dependent) and type II (IgG dependent) immune mechanisms.

Spontaneous and tetracosactide-induced anti-ACTH antibodies in man

CONTEXT

During a clinical trial of regular tetracosactide depot injections, four of 13 patients with autoimmune Addison's disease (AAD) developed adverse reactions immediately following tetracosactide injections. We wished to investigate whether these adverse effects could be due to the production of circulating antitetracosactide (ACTH1-24 ) antibodies.

DESIGN

Anti-ACTH binding activity was investigated using immunoblotting and ELISA on sera from participants in the trial (n = 13; baseline and after tetracosactide exposure), 131 unrelated patients with AAD, 92 patients with Graves' disease (GD), 15 patients with isolated ACTH deficiency and 102 controls. Immunohistochemistry of human pituitary tissue sections was also performed using pooled sera.

RESULTS

Bands at approximately 4 and 6 kDa, corresponding to ACTH1-24 and full-length ACTH1-39, respectively, were found in 10 of 13 (77%) of sera from trial patients exposed to tetracosactide, including all those who had an adverse reaction. This is in contrast with healthy control sera, which showed no binding. The same 10 subjects also showed high levels of binding to tetracosactide by ELISA, along with 21% of patients with AAD, 14% of patients with GD (both P < 0·001 compared to controls) and 1 isolated ACTH deficiency patient (7% of 15). These sera also recognized native ACTH in human pituitary sections.

CONCLUSION

Our study demonstrates that repeated administration of depot tetracosactide can lead to anti-ACTH1-24 autoreactivity. In addition, a significant number of patients with AAD and GD also had similar, spontaneous, anti-ACTH reactivity. The presence of these antibodies could mediate some of the adverse effects or explain the well-described phenomenon of resistance to chronic ACTH therapy.

Hypophysitis: a single-center case series

PURPOSE

The authors review their treatment experience and summarize clinical outcomes for patients with hypophysitis over the past 15 years.

METHODS

A retrospective analysis was conducted on patients with lymphocytic, granulomatous or IgG4-related hypophysitis treated from 1997 to 2014 at a single academic center. Patients' medical records were reviewed and binary logistic regression analysis was used to assess whether various clinical parameters were associated with improved outcomes including endocrine function, radiographic appearance and disease recurrence.

RESULTS

Twenty-one patients (13 women and 8 men) were identified with a median diagnosis age of 37.4 years. All but two patients (90%) were diagnosed histopathologically and the remaining two were diagnosed clinically with lymphocytic hypophysitis. 16 patients (76%) had lymphocytic hypophysitis, 3 (14%) had granulomatous hypophysitis, 1 (5%) had IgG4-related hypophysitis and 1 (5%) had mixed lymphocytic-granulomatous. Patients presented with various symptoms of expanding sellar mass with most common signs including headache (57%), polyuria/polydipsia (52%), vision changes (52%) and amenorrhea or decreased libido (48%). Pre-treatment endocrine evaluation revealed that 12 (57%) patients had complete anterior hypopituitarism, 11 patients (52%) had diabetes insipidus, ten patients (48%) had mild hyperprolactinemia and three patients (14%) had isolated endocrine axis deficiencies with partial gland function. We observed a broad diversity in pre-treatment imaging with common findings including uniform contrast enhancement (62%), thickened infundibulum (57%) and loss of hypophysis bright spot on T1 imaging (43%). Patients were treated with steroids and hormone supplementation as needed. 16 patients (76%) had recorded post-treatment MRI scans which revealed that half had radiographic improvement and half had stable or worsened post-treatment imaging. Only female gender was found to significantly predict improved odds of post-steroid radiographic improvement. For post-treatment endocrine evaluation, six patients (29%) did not have an evaluation on record, four patients (19%) had some improvement in at least one axis, seven patients (33%) had stable but non-worsened endocrine function and four patients (19%) had worsened endocrine function post-steroids.

CONCLUSIONS

Hypophysitis is an increasingly recognized diagnosis that can present with a broad array of radiographic and clinical features. Surgical biopsy can be helpful to make definitive diagnosis and may guide treatment decision-making.

A diagnostic pitfall in IgG4-related hypophysitis: infiltration of IgG4-positive cells in the pituitary of granulomatosis with polyangiitis

INTRODUCTION

Immunoglobulin (Ig) G4-related hypophysitis is an emerging clinical entity, which is characterized by an elevated serum IgG4 concentration and infiltration of IgG4-positive plasma cells in the pituitary. Although some criteria for its diagnosis have been proposed, they have not been fully established. In particular, differential diagnosis from secondary chronic inflammation including granulomatosis with polyangiitis (GPA) is difficult in some cases. We describe central diabetes insipidus with pituitary swelling exhibiting infiltration of IgG4-positive cells.

PATIENT

A 43-year-old woman in the remission stage of GPA presented with sudden-onset polyuria and polydipsia. Pituitary magnetic resonance imaging revealed swelling of the anterior and posterior pituitary and stalk, with heterogeneous gadolinium enhancement and disappearance of the high signal intensity of the posterior pituitary. Evaluation of biochemical markers for GPA suggested that the disease activity was well-controlled. Endocrinological examination revealed the presence of central diabetes insipidus and growth hormone deficiency. Pituitary biopsy specimen showed IgG4-positive cells, with a 43% IgG4(+)/IgG(+) ratio, which met the criteria for IgG4-related hypophysitis. However, substantial infiltration of polymorphonuclear neutrophils with giant cells was also noted, resulting in a final diagnosis of pituitary involvement of GPA.

CONCLUSION

These results suggest that pituitary involvement of GPA should be taken into account for the differential diagnosis of IgG4-related hypophysitis.

Anterior pituitary autoantibodies in patients with type 1 diabetes mellitus: methodological problems and clinical correlations

BACKGROUND

Anti-pituitary antibodies (APA) were described in patients with Type 1 Diabetes (T1D) but their prevalence and relevance remain controversial.

MATERIALS AND METHODS

We evaluated the APA prevalence in Sardinian sera from 100 T1D patients, 70 Type 2 Diabetes (T2D) patients and 62 healthy controls, using indirect immunofluorescence on bovine pituitary sections. To compare two different substrates, we tested using bovine sections, further T1D patient sera (n = 11, from Pisa) previously analysed for APA on monkey sections, while some T1D Sardinian patient sera (n = 22) were tested on monkey sections. According to preliminary experiments, positivity were considered ≥1:200 and ≥1:20 for bovine and monkey substrates, respectively.

RESULTS AND DISCUSSION

Using bovine sections, APA were detected in 7/100 Sardinian T1D patients (at 1:200 titer) and in none of the other Sardinian sera tested. When the T1D sera from Pisa were tested on bovine and the T1D Sardinian sera were tested on monkey, none of these sera showed corresponding positivity for APA. Pituitary hormone dysfunctions were not found in the 7 APA-positive Sardinian T1D patients. The present study shows that the presence of APA at low-titer is highly related to T1D but not associated with any pituitary dysfunction while the animal species used as substrate appears crucial.

CONCLUSION

Further studies are needed to ascertain whether APA detected by different animal species may have different pathological relevance in T1D and/or whether APA in the long run may predict future anterior pituitary dysfunction.

Characterization of pituitary cells targeted by antipituitary antibodies in patients with isolated autoimmune diseases without pituitary insufficiency may help to foresee the kind of future hypopituitarism

PURPOSE

Detection of antipituitary antibodies (APA) at high levels and with a particular immunofluorescence pattern in patients with autoimmune polyendocrine syndromes may indicate a possible future autoimmune pituitary involvement. This longitudinal study was aimed at characterizing in patients with a single organ-specific autoimmune disease the pituitary cells targeted by APA at start, verifying whether this characterization allows to foresee the kind of possible subsequent hypopituitarism.

METHODS

Thirty-six APA positive and 40 APA negative patients with isolated autoimmune diseases participated in the study. None of them had pituitary dysfunction at entry. Characterization by four-layer immunofluorescence of pituitary cells targeted by APA in APA positive patients at entry and study of pituitary function in all patients were performed every 6 months during a 5 year follow-up.

RESULTS

Antipituitary antibodies immunostained selectively one type of pituitary-secreting cells in 21 patients (58.3 %, group 1), and several types of pituitary cells in the remaining 15 (41.7 %, group 2). All patients in group 1 showed subsequently a pituitary insufficiency, corresponding to the type of cells targeted by APA in 18 of them (85.7 %). Only 8 out of 15 patients in group 2 (53.3 %) showed a hypopituitarism, isolated in 7 and combined in the other one. None of APA negative patients showed hypopituitarism.

CONCLUSIONS

The characterization of pituitary cells targeted by APA in patients with isolated autoimmune diseases, when the pituitary function is still normal, may help to foresee the kind of subsequent hypopituitarism, especially when APA immunostained selectively only one type of pituitary cells. A careful follow-up of pituitary function in these patients is advisable to allow an early diagnosis of hypopituitarism, even in subclinical phase and a consequent timely replacement therapy.

Involvement of PIT-1-reactive cytotoxic T lymphocytes in anti-PIT-1 antibody syndrome

CONTEXT

Anti-pituitary-specific transcriptional factor 1 (PIT-1) antibody syndrome is characterized by acquired growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) deficiencies associated with circulating anti-PIT-1 antibodies. Although autoimmunity to PIT-1 has been suggested as a pathogenesis, the precise mechanism of the syndrome remains unclarified.

OBJECTIVE

To elucidate the involvement of antibody- or cell-mediated immunity in anti-PIT-1 antibody syndrome.

MATERIALS AND METHODS

To investigate a direct effect of anti-PIT-1 antibody on pituitary cells, cell proliferation, and cytotoxicity detection assays were performed using patient serum. Enzyme-linked immunospot (ELISpot) assay was performed to evaluate the involvement of PIT-1-reactive cytotoxic T lymphocytes (CTLs). An immunohistochemical analysis using anti-CD4 or anti-CD8 antibody was performed to examine tissue infiltration by CTLs.

RESULTS

Patient serum did not exhibit any inhibitory effect on cell proliferation and secretion of GH and PRL in GH3 cells. In addition, complement-dependent cytotoxicity was not detected in patient serum on GH3 cells or primary pituitary cells. The ELISpot assay revealed the presence of CTLs that specifically reacted to the recombinant PIT-1 protein in the patient's peripheral lymphocytes. CD8(+) cell infiltrations, which is the characteristic of CTLs, were observed in the pituitary gland, adrenal gland, stomach, thyroid gland, liver, and pancreas of the patient with anti-PIT-1 antibody syndrome.

CONCLUSIONS

These results suggest that the anti-PIT-1 antibody is not a cause but a marker of anti-PIT-1 antibody syndrome, in which CTLs play a pivotal role in the pathogenesis.

Detection of pituitary antibodies by immunofluorescence: approach and results in patients with pituitary diseases

CONTEXT

Pituitary antibodies have been measured mainly to identify patients whose disease is caused or sustained by pituitary-specific autoimmunity. Although reported in over 100 publications, they have yielded variable results and are thus considered of limited clinical utility.

OBJECTIVES

Our objectives were to analyze all publications reporting pituitary antibodies by immunofluorescence for detecting the major sources of variability, to experimentally test these sources and devise an optimized immunofluorescence protocol, and to assess prevalence and significance of pituitary antibodies in patients with pituitary diseases. STUDY DESIGN AND OUTCOME MEASURES: We first evaluated the effect of pituitary gland species, section fixation, autofluorescence quenching, blockade of unwanted antibody binding, and use of purified IgG on the performance of this antibody assay. We then measured cross-sectionally the prevalence of pituitary antibodies in 390 pituitary cases and 60 healthy controls, expressing results as present or absent and according to the (granular, diffuse, perinuclear, or mixed) staining pattern.

RESULTS

Human pituitary was the best substrate to detect pituitary antibodies and yielded an optimal signal-to-noise ratio when treated with Sudan black B to reduce autofluorescence. Pituitary antibodies were more common in cases (95 of 390, 24%) than controls (3 of 60, 5%, P = .001) but did not discriminate among pituitary diseases when reported dichotomously. However, when expressed according to their cytosolic staining, a granular pattern was highly predictive of pituitary autoimmunity (P < .0001).

CONCLUSION

We report a comprehensive study of pituitary antibodies by immunofluorescence and provide a method and an interpretation scheme that should be useful for identifying and monitoring patients with pituitary autoimmunity.

Intermediate lobe immunoreactivity in a patient with suspected lymphocytic hypophysitis

Lymphocytic hypophysitis is an organ-specific autoimmune disease characterised by destruction of pituitary hormone-secreting cells due to attack by self-reactive T lymphocytes. The spectrum of pituitary autoantibodies characterised by indirect immunofluorescence (IF) in these patients has not been substantially defined. The purpose of this study was to determine the spectrum of pituitary autoantibodies in 16 lymphocytic hypophysitis patients. Pituitary sections were prepared from guinea pigs and sera from 16 lymphocytic hypophysitis patients (13 biopsy proven and 3 suspected cases) and 13 healthy controls were evaluated for immunoreactivity to the pituitary tissue by immunofluorescence. A single patient was found to have high titre pituitary autoantibodies against guinea pig pituitary tissue. Immunoreactivity was directed against cells of the intermediate lobe. We present the case report of the patient who is a 24 year old woman that presented with headaches, polyuria and polydipsia. A uniformly enlarged pituitary mass was visible on MRI and a diagnosis of suspected lymphocytic hypophysitis was made. Based on our IF study, we postulate this patient has an autoimmune process directed towards the major cell type in the intermediate lobe, the melanotroph. Pre-adsorption with peptides representing adrenocorticotropic hormone, α-melanocyte stimulating hormone or β-endorphin did not affect the IF signal suggesting our patient's pituitary autoantibodies may target some other product of Proopiomelanocortin (POMC) processing, such as corticotrophin-like intermediate peptide or γ-lipoprotein. Alternatively, the autoantibodies may target a peptide completely unrelated to POMC processing.

Occurrence of IgG4-related hypophysitis lacking IgG4-bearing plasma cell infiltration during steroid therapy

Eight years after an episode of multiple IgG4-related disease, a pituitary mass with panhypopituitarism and a visual disturbance developed in a 70-year-old man under low-dose steroid therapy. A pituitary biopsy revealed findings of lymphocytic hypophysitis with the absence of IgG4-positive plasma cell infiltration. The serum IgG4 level was unremarkable. Although performing a pituitary biopsy and measuring the serum IgG4 level is crucial for making a diagnosis of IgG4-related hypophysitis, it is occasionally difficult to diagnose the disease in patients treated with steroid therapy, as observed in the present case. Based on a review of the diagnosis, conducting a careful assessment is required, especially in men and elderly patients thought to have solitary hypophysitis.

Late primary autoimmune hypothyroidism in a patient with postdelivery autoimmune hypopituitarism associated with antibodies to growth hormone and prolactin-secreting cells

BACKGROUND

Pituitary and thyroid autoimmunity can be triggered by pregnancy. We report the first association of combined growth hormone (GH) and prolactin secretion deficiency due to autoimmune damage to GH- and prolactin-secreting cells in a patient with postdelivery lactation failure, presenting subsequently with primary autoimmune hypothyroidism.

PATIENT FINDINGS

A 34-year-old woman presented with lactation failure following the delivery of her first child. She had a family history of hypothyroidism without a history of pituitary dysfunction. Physical examination did not show any abnormal findings. Laboratory investigations showed normal gonadotropin levels after the restoration of normal menstrual cycles following pregnancy, normal basal and stimulated cortisol levels, but an impaired GH response to insulin-induced hypoglycemia, and low basal prolactin and insulin-like growth factor-1 concentrations. Thyroid function was normal when initially investigated three months after delivery, but five months later, marked primary hypothyroidism (thyrotropin levels >100 mIU/L) occurred. Immunological investigation revealed the presence of antipituitary antibodies, identified by double immunofluorescence and targeting GH- and prolactin-secreting cells. Antithyroid antibodies, in the normal range three months postpartum, became significantly elevated when the hypothyroidism appeared. Autoimmune hypophysitis is responsible for selective or multiple pituitary-hormone deficiencies, sometimes involving thyrotropin secretion and causing secondary hypothyroidism, but usually associated with hyperprolactinemia. To our knowledge, this is the first observation of autoimmune hypopituitarism involving deficient growth hormone and prolactin secretion in a patient with lactation failure after delivery, subsequently followed by severe primary autoimmune hypothyroidism, thus falling into an unusual constellation of autoimmune polyendocrine syndrome type 3.

CONCLUSIONS

Considering the well-known relationship between pregnancy and autoimmunity, an early postdelivery immunological and functional investigation in women presenting with disorders of lactation may be useful to detect potential pituitary and thyroid dysfunction even at a subclinical stage.

A case of IgG4-related hypophysitis without pituitary insufficiency

CONTEXT

IgG4-related hypophysitis is a novel clinical disease entity, which is typically complicated by hypopituitarism.

OBJECTIVE

The objective of the study was to describe a novel case of IgG4-related hypophysitis without pituitary insufficiency and summarize the current relevant literature.

PATIENT AND METHODS

A 55-year-old Japanese man presented with an enlarged pituitary gland and bitemporal hemianopsia. Endocrine studies revealed normal pituitary function, although his serum IgG4 level was high. The patient underwent a transsphenoidal biopsy of the pituitary gland, and the pathological tissues were consistent with IgG4-related hypophysitis. Oral prednisolone therapy was started, and after 6 months, his serum IgG4 level decreased and visual field improved.

CONCLUSION

We described the first case of IgG4-related hypophysitis without pituitary insufficiency. However, further case collection is needed to characterize the pathophysiology of IgG4-related hypophysitis.

Pituitary autoimmunity in patients with diabetes mellitus and other endocrine disorders

OBJECTIVE

Pituitary autoimmunity is often found in association with other endocrine autoimmune or non-autoimmune diseases. Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) in patients with Type 1 diabetes mellitus (T1DM) or Type 2 diabetes mellitus (T2DM).

RESEARCH DESIGN AND METHODS

In this casecontrol study 111 patients with T1DM, 110 patients with T2DM, and 214 healthy controls were enrolled in a tertiary referral center. Pituitary, thyroperoxidase, thyroglobulin, 21-hydroxylase, and parietal cell antibodies were assessed in all cases. Endocrine function was further assessed by basal hormone measurement and by dynamic tests, as well as a pituitary magnetic resonance imaging (MRI) was performed in those patients found positive for PitAb.

RESULTS

PitAb prevalence was higher in T1DM (4 out of 111, 3.6%) than in T2DM (0 out of 110, p=0.045) and in healthy subjects (1 out of 214, 0.5% p=0.029). Prevalence of other autoimmune diseases was significantly higher in patients with T1DM (45 out of 111, 40.5%) when compared with patients with T2DM (18 out of 110 T2DM, 16.3%, p<0.001). Patients with T1DM and PitAb positivity were found with a pituitary lesion at MRI in 2 cases and pituitary dysfunction in one case.

CONCLUSIONS

A significant association between pituitary autoimmunity and T1DM was found, in particular in subjects with one or more other endocrine autoimmune diseases.

Wegener granulomatosis as an uncommon cause of panhypopituitarism in childhood

Wegener granulomatosis (WG) is a cytoplasmic antineutrophil cytoplasmic antibody (c-ANCA)-associated, multi-system, necrotizing granulomatous vasculitis. Inflammation of the nasal or oral mucosa, and lung and kidney involvements are typical in the course of the disease. In rare cases, pituitary involvement may occur and cause panhypopituitarism. Pituitary involvement is very rare, and only two pediatric case reports have been published to date out of a total of 24 cases. This is a case report of an adolescent patient who presented with panhypopituitarism symptoms and was later diagnosed with WG. A 16-year-old female patient complained of fever, headache, purulent nasal discharge and severe muscle and joint pain. Additionally, she had polyuria and polydipsia. Investigations revealed a pituitary mass and panhypopituitarism. Positivity of c-ANCA and renal biopsy result compatible with WG confirmed the diagnosis.

Prospective investigation of pituitary functions in patients with acute infectious meningitis: is acute meningitis induced pituitary dysfunction associated with autoimmunity?

Previous case reports and retrospective studies suggest that pituitary dysfunction may occur after acute bacterial or viral meningitis. In this prospective study we assessed the pituitary functions, lipid profile and anthropometric measures in adults with acute bacterial or viral meningitis. Moreover, in order to investigate whether autoimmune mechanisms could play a role in the pathogenesis of acute meningitis-induced hypopituitarism we also investigated the anti-pituitary antibodies (APA) and anti-hypothalamus antibodies (AHA) prospectively. Sixteen patients (10 males, 6 females; mean ± SD age 40.9 ± 15.9) with acute infectious meningitis were included and the patients were evaluated in the acute phase, and at 6 and 12 months after the acute meningitis. In the acute phase 18.7% of the patients had GH deficiency, 12.5% had ACTH and FSH/LH deficiencies. At 12 months after acute meningitis 6 of 14 patients (42.8%) had GH deficiency, 1 of 14 patients (7.1%) had ACTH and FSH/LH deficiencies. Two of 14 patients (14.3%) had combined hormone deficiencies and four patients (28.6%) had isolated hormone deficiencies at 12 months. Four of 9 (44.4%) hormone deficiencies at 6 months were recovered at 12 months, and 3 of 8 (37.5%) hormone deficiencies at 12 months were new-onset hormone deficiencies. At 12 months there were significant negative correlations between IGF-I level vs. LDL-C, and IGF-I level vs. total cholesterol. The frequency of AHA and APA positivity was substantially high, ranging from 35 to 50% of the patients throughout the 12 months period. However there were no significant correlations between AHA or APA positivity and hypopituitarism. The risk of hypopituitarism, GH deficiency in particular, is substantially high in the acute phase, after 6 and 12 months of the acute infectious meningitis. Moreover we found that 6th month after meningitis is too early to make a decision for pituitary dysfunction and these patients should be screened for at least 12 months. In addition, the occurrence of AHA and APA positivity due to acute infectious meningitis was demonstrated for the first time. Further longer-term prospective investigations need to be carried out on a larger cohort of patients to understand the role of autoimmunity in the pathogenesis of late hypopituitarism after acute infectious meningitis.

Prevalence of antipituitary antibodies in acromegaly

Acromegaly is a rare disorder due to an excessive production of growth hormone (GH), typically caused by a GH-secreting pituitary adenoma. Anti-pituitary antibodies (APAs) are often seen in patients with different kinds of pituitary pathologies. Because GH has been proposed as a possible antigen recognized by such antibodies, the prevalence of APAs may be higher in conditions characterized by excessive GH secretion. The primary aim of this study was to compare the prevalence of APAs in patients with acromegaly and in controls with other types of pituitary tumors and healthy subjects. Secondary aim was to characterize the pituitary cells targeted by the APAs. Thirty eight acromegaly patients and 215 controls, including 38 patients with prolactinomas, 64 with non-functioning pituitary adenomas (NFPA), and 113 healthy subjects were enrolled in the study. All subjects were tested for APAs using indirect immunofluorescence. Target cells recognized by APAs were identified by double staining immunofluorescence. APAs were significantly more prevalent in acromegaly cases than in healthy controls (10.5% vs. 1.8%, P < 0.05). This prevalence was similar to that found in patients with prolactinomas (7.9%) and NFPA (12.5%). Among APAs-positive subjects, antibodies recognizing somatotrope cells were more common in acromegaly cases than in healthy controls (3/4 vs. 0/113, P < 0.0001), but had similar frequencies in NFPA (2/8) and prolactinomas (1/3). APAs are more frequently found in patients with pituitary adenomas than healthy subjects, with no significant difference among the tumor types studied. GH-secreting cells could represent a target of the autoimmune response.

Pituitary autoimmune disease: nuances in clinical presentation

Pituitary autoimmune disease is considered an autoimmune organ-specific disorder, characterized by a pituitary infiltration of lymphocytes, macrophages, and plasma cells that could lead to loss of pituitary function. Hypophysitis may be secondary to systemic diseases or infections. Primary pituitary hypophysitis is classified into lymphocytic, granulomatous, xanthomatous, mixed forms (lymphogranulomatous, xanthogranulomatous), necrotizing and IgG4 plasmacytic, according to the histological findings. Concerning lymphocytic hypophysitis (LH), it is characterized by lymphocytic infiltration and can be subclassified according to the affected area on: lymphocytic adenohypophysitis, lymphocytic infundibulo-neurohypophysitis and lymphocytic panhypophysitis. LH had always been considered a rare disease. Nevertheless, with improved imaging techniques, especially magnetic resonance imaging (MRI), LH diagnosis has been increased. This disease usually affects young women during pregnancy or postpartum period with headache, visual impairment, ACTH deficiency and a homogenous sellar mass with thickening of pituitary stalk in MRI. Definitive diagnosis depends on histopathological evaluation; nevertheless, a presumptive diagnosis could be done in a typical case. As no specific autoantigen was identified in LH, there is no antipituitary antibody (APA) method available for helping diagnosis. However, APA used in some centers for research could support an autoimmune origin for some hypopituitarism previously named as idiopathic, confirming nuances in clinical presentation of pituitary autoimmune disease. Therapeutic approach should be based on the grade of suspicious and clinical manifestations of LH.

Management of immune-related adverse events and kinetics of response with ipilimumab

Monoclonal antibodies directed against the immune checkpoint protein cytotoxic T-lymphocyte antigen-4 (CTLA-4; CD152)-ipilimumab and tremelimumab-have been investigated in metastatic melanoma and other cancers and have shown promising results. Recently, ipilimumab was approved by the US Food and Drug Administration for the treatment of metastatic melanoma. We review the literature on managing the adverse effects and kinetics of tumor regression with ipilimumab and provide guidelines on their management. During treatment with these antibodies, a unique set of adverse effects may occur, called immune-related adverse events (irAEs). These include rashes, which may rarely progress to life-threatening toxic epidermal necrolysis, and colitis, characterized by a mild to moderate, but occasionally also severe and persistent diarrhea. Hypophysitis, hepatitis, pancreatitis, iridocyclitis, lymphadenopathy, neuropathies, and nephritis have also been reported with ipilimumab. Early recognition of irAEs and initiation of treatment are critical to reduce the risk of sequelae. Interestingly, irAEs correlated with treatment response in some studies. Unique kinetics of response have been observed with CTLA-4 blockade with at least four patterns: (1) response in baseline lesions by week 12, with no new lesions seen; (2) stable disease, followed by a slow, steady decline in total tumor burden; (3) regression of tumor after initial increase in total tumor burden; and (4) reduction in total tumor burden during or after the appearance of new lesion(s) after week 12. We provide a detailed description of irAEs and recommendations for practicing oncologists who are managing them, along with the unusual kinetics of response associated with ipilimumab therapy.

Pituitary antibodies in women with Hashimoto's thyroiditis: prevalence in diagnostic and prediagnostic sera

BACKGROUND

Pituitary antibodies have been reported with greater frequency in patients with Hashimoto's thyroiditis than in healthy controls, although there is significant variability in the strength of the association and the methodologies used.

METHODS

We designed a nested case-control study to characterize the prevalence of pituitary antibodies at the time of the clinical diagnosis of Hashimoto's thyroiditis, as well as at 2, 5, and 7 years before diagnosis. Active component female service member cases (n=87) and matched female controls (n=107) were selected using the Defense Medical Surveillance System database (DMSSD) between January 1998 and December 2007. Pituitary antibodies were measured by immunofluorescence using human pituitary glands collected at autopsy as the substrate.

RESULTS

At diagnosis, pituitary antibodies were present in 9% of cases with Hashimoto's (8 of 87) and 3% of controls (3 of 107). When the data were analyzed using a conditional logistic regression model, which takes into account the matching on age and work status, pituitary antibodies increased the odds of having Hashimoto's thyroiditis by sevenfold (95% confidence interval from 1.3 to 40.1, p=0.028), after adjusting for components of the DMSSD-category-termed race and for thyroperoxidase antibodies. Before diagnosis, pituitary antibodies were positive in 3 of the 11 subjects (2 cases and 1 control) at the -2-year time point, and negative in all 11 subjects at the -5- and -7-year time points.

CONCLUSIONS

In summary, using a nested case-control design, we confirm that pituitary antibodies are more common in Hashimoto's thyroiditis and suggest that they appear late during its natural history.

Identification of TPIT and other novel autoantigens in lymphocytic hypophysitis: immunoscreening of a pituitary cDNA library and development of immunoprecipitation assays

BACKGROUND

Lymphocytic hypophysitis is an organ-specific autoimmune disease of the pituitary gland. A specific and sensitive serological test currently does not exist to aid in the diagnosis.

OBJECTIVE

To identify target autoantigens in lymphocytic hypophysitis and develop a diagnostic assay for these proteins.

DESIGN/METHODS

A pituitary cDNA expression library was immunoscreened using sera from four patients with lymphocytic hypophysitis. Relevant cDNA clones from screening, along with previously identified autoantigens pituitary gland-specific factor 1a and 2 (PGSF1a and PGSF2) and neuron-specific enolase (NSE) were tested in an in vitro transcription and translation immunoprecipitation assay. The corticotroph-specific transcription factor, TPIT, was investigated separately as a candidate autoantigen.

RESULTS

Significantly positive autoantibody reactivity against TPIT was found in 9/86 hypophysitis patients vs 1/90 controls (P = 0.018). The reactivity against TPIT was not specific for lymphocytic hypophysitis with autoantibodies detectable in the sera from patients with other autoimmune endocrine diseases. Autoantibodies were also detected against chromodomain-helicase-DNA binding protein 8, presynaptic cytomatrix protein (piccolo), Ca(2+)-dependent secretion activator, PGSF2 and NSE in serum samples from patients with lymphocytic hypophysitis, but at a frequency that did not differ from healthy controls. Importantly, 8/86 patients with lymphocytic hypophysitis had autoantibodies against any two autoantigens in comparison with 0/90 controls (P = 0.0093).

CONCLUSIONS

TPIT, a corticotroph-specific transcription factor, was identified as a target autoantigen in 10.5% of patients with lymphocytic hypophysitis. Further autoantigens related to vesicle processing were also identified as potential autoantigens with different immunoreactivity patterns in patients and controls.

Pituitary and systemic autoimmunity in a case of intrasellar germinoma

Germinomas arising in the sella turcica are difficult to differentiate from autoimmune hypophysitis because of similar clinical and pathological features. This differentiation, nevertheless, is critical for patient care due to different treatments of the two diseases. We report the case of an 11-year-old girl who presented with diabetes insipidus and growth retardation, and was found to have an intra- and supra-sellar mass. Initial examination of the pituitary biopsy showed diffuse lymphocytic infiltration of the adenohypophysis and absent placental alkaline phosphatase expression, leading to a diagnosis of hypophysitis and glucocorticoid treatment. Because of the lack of clinical and radiological response, the pituitary specimen was re-examined, revealing this time the presence of scattered c-kit and Oct4 positive germinoma cells. The revised diagnosis prompted the initiation of radiotherapy, which induced disappearance of the pituitary mass. Immunological studies showed that the patient's serum recognized antigens expressed by the patient's own germinoma cells, as well as pituitary antigens like growth hormone and systemic antigens like the Sjögren syndrome antigen B and alpha-enolase. The study first reports the presence of pituitary and systemic antibodies in a patient with intrasellar germinoma, and reminds us that diffuse lymphocytic infiltration of the pituitary gland and pituitary antibodies does not always indicate a diagnosis of autoimmune hypophysitis.

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.

Detection of antipituitary and antihypothalamus antibodies to investigate the role of pituitary or hypothalamic autoimmunity in patients with selective idiopathic hypopituitarism

OBJECTIVE

Antipituitary (APA) but not antihypothalamus antibodies (AHA) have been investigated in patients with idiopathic hypopituitarism. This study searched for APA and AHA in some of these patients to investigate whether pituitary or hypothalamic autoimmunity could play a role in their pituitary dysfunction.

DESIGN

Sixty-six patients with selective idiopathic hypopituitarism were studied: 27 with ACTH deficiency, 20 with GH deficiency and 19 with hypogonadotropic hypogonadism. Twenty patients with hypopituitarism secondary to hypophysectomy and 50 healthy subjects were enrolled as controls.

MEASUREMENTS

Antipituitary and AHA were evaluated by indirect immunofluorescence in sera of patients and controls. Positive sera were retested by a four-layer double immunofluorescence to identify the cells targeted by these antibodies.

RESULTS

Antipituitary were present at high titre in 4 of 27 patients with ACTH deficiency (14·8%), 4 of 20 with GH deficiency (26%) and 5 of 19 with hypogonadotropic hypogonadism (21%) and targeted, respectively, corticotrophs, somatotrophs and gonadotrophs. AHA were found at high titre only in 5 patients with ACTH deficiency (18·5%), mostly targeting corticotrophin-releasing hormone-secreting cells; none of these 5 patients resulted positive for antipituitary antibodies. Among the controls, only 1 hypophysectomized patient resulted APA positive at low titre.

CONCLUSIONS

Our results suggest that in patients with selective idiopathic hypopituitarism, detection of APA or AHA could better characterize an autoimmune process involving the pituitary or hypothalamus, respectively. In particular, detection of antibodies targeting selectively ACTH-secreting or corticotrophin-releasing hormone-secreting cells may differentiate, respectively secondary from tertiary variants of autoimmune hypoadrenalism.

Placenta suppresses experimental autoimmune hypophysitis through soluble TNF receptor 1

Pregnancy modulates autoimmune diseases through diverse and still incompletely defined mechanisms, in part operating at the decidua-placenta interface. To assess the immunological contribution of placenta, we administered mouse placental proteins to a mouse model of autoimmune hypophysitis, a disease known to be strongly associated with pregnancy. Emulsified placental proteins suppressed both the cellular and humoral aspects of hypophysitis. Suppression was specific to self antigens and not seen when two foreign antigens, tetanus toxoid or tuberculin purified protein derivative, were used. Proteomic analysis revealed high levels of soluble TNF receptor 1 in placenta, suggesting that blockade of the TNF-α pathway was a mechanism of disease suppression. Placentas derived from mice deficient in TNF receptor 1 lost the ability to suppress hypophysitis. Notably, hypophysitis suppression was seen only when the TNF-α pathway was blocked locally, at the site of immunization, and not systemically. These findings provide evidence that placenta contributes to the immune tolerance of pregnancy by locally inhibiting the TNF-α pathway.

IgG4-related hypophysitis: a new addition to the hypophysitis spectrum

CONTEXT

Hypophysitis is a chronic inflammation of the pituitary gland that comprises an increasingly complex clinicopathological spectrum. Within this spectrum, lymphocytic and granulomatous hypophysitis are the most common forms, but newer variants have recently been reported.

OBJECTIVE

The aims of the study were to describe a new patient with IgG4-related hypophysitis, review the published literature, and provide diagnostic criteria.

SETTING

A 75-yr-old man presented with a 1-yr history of frontal headache. Initial studies revealed panhypopituitarism and a mass in both the sella turcica and the sphenoidal sinus. The patient underwent transphenoidal surgery, initiated high-dose prednisone followed by hormone replacement therapy, and was closely monitored for 3 yr.

RESULTS

Symptoms improved after prednisone, along with shrinkage of the pituitary and sphenoidal masses, but recurred when prednisone dose was lowered. Histopathology showed a marked mononuclear infiltrate in both the pituitary and sphenoidal specimens, mainly characterized by increased numbers of plasma cells. Many of the infiltrating plasma cells (>10 per high-power field) were IgG4-positive. Review of the literature identified 11 cases of IgG4-related hypophysitis (two diagnosed based on pituitary histopathology).

CONCLUSIONS

We describe the first Caucasian patient with biopsy-proven IgG4-related hypophysitis and provide classification criteria for this disease.

A case of central diabetes insipidus following probable type A/H1N1 influenza infection

The major causes of central diabetes insipidus (CDI) are neoplastic or infiltrative lesions of the hypothalamus or pituitary gland, severe head injuries, or pituitary or hypothalamic surgery. Lymphocytic infundibuloneurophysitis (LINH) is associated with autoimmune inflammatory disease of the pituitary gland, but the exact etiology is unknown. CDI caused by viral infections has been rarely reported. Here, we describe the case of a 22-year-old man who was in good health until 2 months prior to admission, presented with acute development of polyuria and polydipsia, and showed increased urinary volume up to 9000 mL/day. The patient showed elevated serum osmolality and low urine osmolality, with a low level of antidiuretic hormone. Endocrinological findings revealed CDI, but his arterial pituitary function appeared normal. Magnetic resonance imaging revealed significant enlargement of the pituitary stalk. We suspected CDI due to LINH based on non-transsphenoidal biopsy findings. He was diagnosed as type A influenza,and given oral therapeutic agents. However, acute onset of polyuria and polydipsia occurred 10 days after the influenza diagnosis. The available epidemiological information regarding the outbreak of influenza around that time strongly suggested that the patient was infected with the A/H1N1 influenza virus, although this virus had not been detected on polymerase chain reaction testing. In the present case, the autoimmune mechanism of LINH may have been associated with novel influenza A/H1N1 virus infection.

IgG4-related systemic disease in a Native American man

IgG4-related systemic disease is a recently described entity that can elude even the most astute diagnostician. Patients with the disease, characterized by the infiltration of polyclonal IgG4-positive plasmacytes, can present with single or multi-organ involvement. Manifestations include dacryoadenitis, sialadenitis, thyroiditis, pneumonitis, retroperitoneal fibrosis, pancreatitis, sclerosing cholangitis, tubulointerstitial nephritis, prostatitis, and hypophysitis. We describe a biopsy-confirmed case with extensive multi-organ involvement, including hypophysitis, dacryoadenitis, retroperitoneal fibrosis and tubulointerstitial nephritis. By reporting this case, we hope to bring IgG4-related systemic disease to the attention of the broader medical community as it is an elusive disease that commonly responds to systemic corticosteroids.

Investigation of antihypothalamus and antipituitary antibodies in amateur boxers: is chronic repetitive head trauma-induced pituitary dysfunction associated with autoimmunity?

OBJECTIVE

Current data clearly demonstrate that sports-related chronic repetitive head trauma due to boxing might result in hypopituitarism. However, the mechanism of sports-related traumatic brain injury-induced pituitary dysfunction is still unclear. In order to understand whether autoimmune mechanisms could play a role in the pituitary dysfunction due to sports-related head trauma, we investigated the presence of antipituitary antibodies (APAs) and antihypothalamus antibodies (AHAs) in amateur boxers.

PATIENTS AND DESIGN

Sixty-one actively competing (n=44) or retired (n=17) male boxers (mean age, 26 years; range, 17-53) who had been evaluated regarding pituitary functions previously were included in the study. In all boxers and in 60 age/sex-similar normal controls, AHAs and APAs were investigated by an indirect immunofluorescence method.

RESULTS

AHAs were detected in 13 of 61 boxers (21.3%), and APAs were detected in 14 of 61 boxers (22.9%), but in none of the normal controls. Pituitary dysfunction was significantly higher in AHA-positive boxers (46.2%) than in AHA-negative boxers (10.4%) (P=0.003). There was a significant association between AHA positivity and hypopituitarism due to boxing (odds ratio: 7.37, 95% confidence interval 1.8-30.8). There was no significant association between APA positivity and hypopituitarism.

CONCLUSIONS

This study demonstrates for the first time the presence of AHAs and APAs in boxers who were exposed to sports-related head trauma. Moreover, the present investigation provides preliminary evidence that AHAs are associated with the development of pituitary dysfunction in boxers, thus suggesting that autoimmunity may have a role in the pathogenesis.