The early-stage clinical course of anti-pituitary-specific transcription factor-1 hypophysitis diagnosed post-immune checkpoint inhibitor treatment: A case with review of literature.

Anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis, a paraneoplastic syndrome resulting from an autoimmune response against PIT-1, typically manifests with undetectable levels of growth hormone (GH) and prolactin (PRL), and significantly low levels of serum thyroid-stimulating hormone (TSH) at diagnosis. These hormonal levels are highly specific to this disease and serve as key diagnostic indicators. Herein, we present a detailed clinical course of a 69-year-old male with a history of gastric cancer and lymph node metastases who developed anti-PIT-1 hypophysitis after the initiation of immune checkpoint inhibitor (ICI) therapy, specifically nivolumab, oxaliplatin, and capecitabine. The patient was referred to our department owing to decreased TSH, free triiodothyronine (T3), and free thyroxine (T4) levels after two doses of nivolumab. Initially suspected as central hypothyroidism due to ICI-related hypophysitis, further assessment confirmed the diagnosis of anti-PIT-1 hypophysitis. Notably, GH, PRL, and TSH levels markedly declined, leading to complete deficiencies 2 months after the first nivolumab dose-a pattern consistent with that of previous cases of anti-PIT-1 hypophysitis. Therefore, this report not only presents an atypical subset of ICI-related hypophysitis but also delineates the process of hormone impairment leading to complete deficiencies in anti-PIT-1 hypophysitis. This case highlights the importance of vigilant monitoring for endocrine issues in patients undergoing ICI therapy, given the escalating incidence of immune-related adverse events associated with the extensive use of ICI therapy for various cancers.

Fluctuations in plasma adrenocorticotropic hormone concentration may predict the onset of immune checkpoint inhibitor-related hypophysitis.

Immune checkpoint inhibitor (ICI)-related hypophysitis (RH) is a common immune-related adverse event. The early detection of ICI-RH prevents life-threatening adrenal insufficiency. However, good predictors of secondary adrenal insufficiency in ICI-RH have not yet been reported. We hypothesized that fluctuations in serum adrenocorticotropic hormone (ACTH) and cortisol levels occur similarly to those in thyroid-stimulating hormone and thyroid hormone (thyroxine and triiodothyronine) levels in ICI-related thyroiditis. Here, we sought to test this hypothesis. Patients who used ICI and had a history of measurement of serum ACTH and cortisol concentrations were retrieved from electronic medical records, and those with a history of glucocorticoid use were excluded from the analysis. We evaluated fluctuations in serum ACTH and cortisol concentrations and the development of ICI-RH. For patients with ICI-RH, data at three points (before ICI administration (pre), maximum ACTH concentration (peak), and onset of ICI-RH) were analyzed to evaluate hormone fluctuations. A total of 202 patients were retrieved from the medical record. Forty-three patients were diagnosed with ICI-RH. Twenty-six out of 43 patients had sufficient data to evaluate fluctuations in serum ACTH and cortisol concentrations and no history of glucocorticoid use. ACTH concentrations changed from 37.4 (29.9-48.3) (pre) to 64.4 (46.5-106.2) (peak) pg/mL (1.72-fold increase, p=0.0026) in the patients with ICI-RH before the onset. There were no differences in cortisol concentrations between the pre and peak values in patients with ICI-RH. We also evaluated the fluctuations in serum ACTH and cortisol levels in patients who did not receive ICI-RH (62 cases). However, elevation of serum ACTH levels was not observed in patients without ICI-RH, suggesting that transient elevation of serum ACTH levels is a unique phenomenon in patients with ICI-RH. In conclusion, serum ACTH levels were transiently elevated in some patients with ICI-RH before the onset of secondary adrenal insufficiency. Monitoring the ACTH levels and their fluctuations may help predict the onset of ICI-RH.

Effects of the Cortisol Milieu on Tumor-Infiltrating Immune Cells in Corticotroph Tumors.

CONTEXT: Corticotrophs are susceptible to lymphocyte cytotoxicity, as seen in hypophysitis, suggesting that an immunological approach may be a potential strategy for corticotroph-derived tumors. OBJECTIVE: We aimed to clarify whether corticotroph tumors that induce hypercortisolemia (ACTHomas) could be targets for immunotherapy. METHODS: Tumor-infiltrating immune cells were immunohistochemically analyzed. ACTHomas were compared with other pituitary tumors, and further divided into 3 different cortisol-exposed milieus: Naïve (ACTHomas without preoperative treatment), Met (ACTHomas with preoperative metyrapone), and SCA (silent corticotroph adenomas). A 3-dimensional cell culture of resected tumors was used to analyze the effects of immune checkpoint inhibitors. RESULTS: The number of tumor-infiltrating lymphocytes (TILs) was low in ACTHomas. Among these, the number of CD8+ cells was lower in ACTHomas than in both somatotroph and gonadotroph tumors (both P < .01). Then we compared the differences in TILs among Naïve, Met, and SCA. The number of CD4+ cells, but not CD8+ cells, was higher in both Met and SCA than in Naïve. Next, we investigated tumor-associated macrophages, which could negatively affect T cell infiltration. The numbers of CD163+ and CD204+ cells were positively associated with cortisol levels. Moreover, tumor size was positively correlated with the number of CD204+ cells. CONCLUSION: We found the possibility that ACTHomas were immunologically cold in a cortisol-independent manner. In contrast, the tumor infiltration of CD4+ cells and M2-macrophages were associated with the cortisol milieu. Future studies are needed to validate these results and develop effective immunotherapy while considering the cortisol milieu.

The combination of doxazosin and metyrosine as a preoperative treatment for pheochromocytomas and paragangliomas.

PURPOSE: Preoperative medical management is critical to prevent intraoperative cardiovascular complications in patients with pheochromocytomas and paragangliomas (PPGLs). Initial treatment involves α-adrenergic receptor blockers. However, while the routine use of metyrosine alongside these blockers is not strongly recommended due to a lack of evidence supporting its efficacy and associated safety concerns, there are previous studies on combination therapy with phenoxybenzamine and metyrosine. There are few reports on combination therapy with the selective α1-adrenergic receptor blocker doxazosin. Therefore, we investigated this combination treatment, which theoretically can affect perioperative outcomes in patients with PPGLs. To our knowledge, this is the first such study. METHODS: This retrospective single-center observational study involved 51 patients who underwent surgical resection of PPGLs at Kobe University Hospital between 2014 and 2022. All patients received doxazosin at maximum doses. Fourteen patients received concomitant metyrosine, while 37 received doxazosin alone. Their perioperative outcomes were compared. RESULTS: No severe event, such as acute coronary syndrome, was observed in either group. Intraoperatively, the doxazosin + metyrosine group exhibited a lower median minimum systolic blood pressure (56 [54-60] vs. 68 [59-74] mmHg, P = 0.03) and required lower median remifentanil (P = 0.04) and diltiazem (P = 0.02) doses than the doxazosin-alone group. CONCLUSION: The combination of metyrosine and doxazosin as a preoperative treatment for PPGLs affects intraoperative circulatory hemodynamics, such as a reduced occurrence of blood pressure elevation during surgery. Further research is necessary to identify patients who will benefit most from this combination treatment.

Newer parameters of the octreotide test in patients with acromegaly.

PURPOSE: Predicting the therapeutic effects of first-generation somatostatin receptor ligands (fg-SRLs) is important when assessing or planning effective treatment strategies in patients with acromegaly. The oft-used maximum growth hormone (GH) suppression rate parameter of the octreotide test has a suboptimal predictive value. Therefore, this study explored newer parameters of the octreotide test for predicting the therapeutic effect of long-acting fg-SRLs. METHODS: In this single-center retrospective study, the octreotide test parameters and the therapeutic effects of fg-SRL at 3 months were investigated in 45 consecutive treatment-naïve patients with acromegaly between April 2008 and March 2023. Additionally, the relationship between the octreotide test parameters and the therapeutic effects of fg-SRLs was investigated. Tumor shrinkage was evaluated based on changes in the longitudinal diameter of the macroadenomas. The area GH suppression rate-time under the curve (AUC) and the time to nadir GH level were calculated and compared with the maximum GH suppression rate. RESULTS: The AUC estimated reductions in serum insulin-like growth factor I, and tumor shrinkage. The time to nadir GH level predicted tumor shrinkage more robustly than the maximum GH suppression rate in patients with macroadenoma. CONCLUSION: The AUC and time to nadir GH level may potentially be newer parameters of the octreotide test for estimating the therapeutic effect of fg-SRLs.

Clinical features of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis: a new aspect of paraneoplastic autoimmune condition.

The pathogenesis of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis was gradually revealed as cases emerged. Our comprehensive analysis, including all reported cases, identified a new instance of anti-PIT-1 hypophysitis postimmune checkpoint inhibitor therapy. All 9 patients exhibited extremely low growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels; 2 had a slightly atrophic pituitary gland; 4 had thymoma, and 5 had malignant neoplasms of diffuse large B-cell lymphoma (DLBCL) and other origins. Patients with thymoma showed multiple autoimmune diseases. HLA-A*24:02 and/or A*02:06 were present in six and DR53 in 5 cases analyzed. High anti-PIT-1 antibody titers and ectopic PIT-1 expression in the cytosol and nucleus of the tumor tissues were observed in patients with thymoma or DLBCL, whereas it was exclusively observed in the nuclei of a bladder cancer patient. These findings provide new insights into the pathophysiology of paraneoplastic autoimmune hypophysitis.

Paraneoplastic isolated adrenocorticotropic hormone deficiency revealed after immune checkpoint inhibitors therapy: new insights into anti-corticotroph antibody.

Introduction: A recently discovered facet of paraneoplastic adrenocorticotropic hormone (ACTH) deficiency exists in two forms: a paraneoplastic spontaneous isolated ACTH deficiency (IAD) and an immune checkpoint inhibitor (ICI)-related hypophysitis. Autoantibodies against corticotrophs, such as circulating anti-proopiomelanocortin (POMC) antibodies are considered disease markers. However, the number of identified cases was limited, implying that the characteristics of these autoantibodies are not fully understood. Methods: We investigate circulating autoimmune autoantibodies in detail through a novel case of IAD that developed as a paraneoplastic autoimmune ACTH deficiency. Results: The patient developed IAD after 25 weeks of ICI therapy for metastasis of large-cell neuroendocrine carcinoma at 69 years of age. Ectopic ACTH expression and infiltration of CD3+, CD4+, CD8+, and CD20+ lymphocytes were observed in the tumor tissues and circulating anti-POMC antibodies were detected specifically in the patient's serum. Moreover, detailed analyses of immunofluorescence staining using patient serum revealed that the recognition site of the autoantibody was ACTH25-39, which had not been identified in previous cases of paraneoplastic autoimmune ACTH deficiency. Conclusion: This case involved a combination of paraneoplastic spontaneously acquired IAD and ICI-related hypophysitis occupying the middle ground. Moreover, our study reveals new aspects of anti-POMC antibodies in patients with paraneoplastic ACTH deficiency. This report expands our understanding of the immunological landscape and provides new insights for the identification of antibodies associated with paraneoplastic autoimmune ACTH deficiency.

Combined Hypophysitis and Type 1 Diabetes Mellitus Related to Immune Checkpoint Inhibitors.

Context: The occurrence of multiple endocrinopathies due to immune checkpoint inhibitors (ICIs) is a relatively common adverse event. However, the occurrence of a combination of hypophysitis and type 1 diabetes mellitus (T1DM) is extremely rare, and its clinical features are unclear. Objective: We comparatively analyzed the clinical features of this combination and each individual ICI-induced endocrinopathy. Methods: We reported 3 cases that we encountered and reviewed previously reported cases of patients with combined hypophysitis and T1DM due to ICIs. Results: Anti-programmed cell death-1 (anti-PD-1) antibodies were prescribed to all 3 cases. The duration from ICI initiation to the onset of endocrine disease was 12 to 48 weeks. Several human leukocyte antigen (HLA) haplotypes that have disease susceptibility to hypophysitis were detected in all 3 patients. With the 17 previously reported cases, combined endocrinopathies were more common in men (85%). The onset age was in the 60s for both combined and single endocrinopathies. Anti-PD-1 antibodies were used in most of the cases (90%). The time from ICI initiation to the onset of endocrinopathies was 24 (8-76) weeks for hypophysitis and 32 (8-76) weeks for T1DM in patients with combined endocrinopathies, which was not significantly different from that for each single endocrinopathy. Conclusion: We presented 3 cases of patients with combined endocrinopathies of hypophysitis and T1DM that may have been caused by anti-PD-1 antibodies. There was no difference in the time from ICI initiation to the onset of endocrinopathies between combined and single endocrinopathies. Further case accumulation and pathogenic investigations are required.

Survey of glucocorticoid dose escalation in patients with adrenal insufficiency during the peri-COVID-19 vaccination period.

There is uncertainty regarding the need for COVID-19 peri-vaccination glucocorticoid coverage in patients with adrenal insufficiency. In this survey conducted in a single tertiary medical institution, 167 consecutive outpatients taking physiological glucocorticoids because of adrenal insufficiency were included. The patients declared if they developed an adrenal crisis after vaccination, and the amount and duration of an increase in their glucocorticoid dosage, if any. None of the patients without preventive glucocorticoid increase suffered an adrenal crisis after COVID-19 vaccination. Only 8.3% (14 cases) and 27.5% (46 cases) of the patients needed to escalate the dose of glucocorticoids when systemic symptoms appeared after the first and second injections, respectively. Glucocorticoids were increased in patients <60 years of age more than in patients ≥60 years of age at the time of both the first (p = 0.026) and second injections (p = 0.005). Sex and the causes of adrenal insufficiency were not associated with the frequency of the patients who needed glucocorticoid dose escalation. In the cases with increased glucocorticoids, the median dosage for escalation was 10 mg (hydrocortisone equivalent). In conclusion, even without prophylactic glucocorticoid administration, adrenal crisis did not occur during the peri-COVID-19 vaccination period. The dose escalation of steroid was more frequent in younger patients following the second vaccination. Careful monitoring of adverse effects and the appropriate management of glucocorticoids when necessary are essential following COVID-19 vaccinations.

Novel genes and variants associated with congenital pituitary hormone deficiency in the era of next-generation sequencing.

Combined pituitary hormone deficiency (CPHD) is not a rare disorder, with a frequency of approximately 1 case per 4,000 live births. However, in most cases, a genetic diagnosis is not available. Furthermore, the diagnosis is challenging because no clear correlation exists between the pituitary hormones affected and the gene(s) responsible for the disorder. Next-generation sequencing (NGS) has recently been widely used to identify novel genes that cause (or putatively cause) CPHD. This review outlines causative genes for CPHD that have been newly reported in recent years. Moreover, novel variants of known CPHD-related genes (POU1F1 and GH1 genes) that contribute to CPHD through unique mechanisms are also discussed in this review. From a clinical perspective, variants in some of the recently identified causative genes result in extra-pituitary phenotypes. Clinical research on the related symptoms and basic research on pituitary formation may help in inferring the causative gene(s) of CPHD. Future NGS analysis of a large number of CPHD cases may reveal new genes related to pituitary development. Clarifying the causative genes of CPHD may help to understand the process of pituitary development. We hope that future innovations will lead to the identification of genes responsible for CPHD and pituitary development.

Differentiation of human induced pluripotent stem cells into hypothalamic vasopressin neurons with minimal exogenous signals and partial conversion to the naive state.

Familial neurohypophyseal diabetes insipidus (FNDI) is a degenerative disease of vasopressin (AVP) neurons. Studies in mouse in vivo models indicate that accumulation of mutant AVP prehormone is associated with FNDI pathology. However, studying human FNDI pathology in vivo is technically challenging. Therefore, an in vitro human model needs to be developed. When exogenous signals are minimized in the early phase of differentiation in vitro, mouse embryonic stem cells (ESCs)/induced pluripotent stem cells (iPSCs) differentiate into AVP neurons, whereas human ESCs/iPSCs die. Human ESCs/iPSCs are generally more similar to mouse epiblast stem cells (mEpiSCs) compared to mouse ESCs. In this study, we converted human FNDI-specific iPSCs by the naive conversion kit. Although the conversion was partial, we found improved cell survival under minimal exogenous signals and differentiation into rostral hypothalamic organoids. Overall, this method provides a simple and straightforward differentiation direction, which may improve the efficiency of hypothalamic differentiation.

Bilateral adrenal uptake of 123I MIBG scintigraphy with mild catecholamine elevation, the diagnostic dilemma, and its characteristics.

Cases in which bilateral adrenal 123I-Metaiodobenzylguanidine (123I-MIBG) scintigraphy accumulation is sometimes shown, with mildly elevated catecholamine (CA) or metanephrine (MN) levels (within 3 times the upper reference limit) are diagnostic dilemmas. We experienced 3 cases of adrenal incidentalomas with this dilemma in the differential diagnosis. The clinical diagnosis was subclinical Cushing's syndrome in 2 cases, and primary aldosteronism in 1. Despite suspected CA excess in clinical symptoms and imaging findings, the pathological findings of all these tumors were revealed to be cytochrome P450 family 11 subfamily B member 1 (CYP11B1) positive adrenocortical adenomas. Interestingly, adrenal medullary hyperplasia (AMH) was detected in the adrenal parenchyma of all those backgrounds. To clarify the clinical features of such cases, a cross-sectional study was conducted at the Kobe University Hospital from 2014 to 2020. One-hundred sixty-four patients who had undergone 123I-MIBG scintigraphy were recruited. Among them, 10 patients (6.1%) met the above criteria, including the presented 3 cases. Plasma adrenaline, noradrenaline, urinary metanephrine, and normetanephrine had values of 0.05 ± 0.05 ng/mL, 0.63 ± 0.32 ng/mL, 0.22 ± 0.05 mg/day, and 0.35 ± 0.16 mg/day, respectively. Nine cases were complicated with hypertension, and symptoms related to CA excess were observed. Half of them (5 cases) including presented 3 cases had unilateral adrenal tumors. These suggest that in cases of bilateral adrenal uptake on 123I-MIBG, AMH needs to be considered. Adrenocortical adenomas may be associated with AMH and further larger investigation is needed for this pathology.

Responsiveness to DDAVP in Cushing's disease is associated with USP8 mutations through enhancing AVPR1B promoter activity.

PURPOSE: To clarify the characteristics of Cushing's disease (CD) patients who respond to the desmopressin (DDAVP) test and its underlying mechanisms. METHODS: Forty-seven patients with CD who underwent DDAVP testing were included. Patients were divided into two groups: DDAVP test (+) (adrenocorticotropic hormone [ACTH] levels increased by ≥ 1.5-fold during the DDAVP test) and DDAVP test (-) (ACTH levels increased by < 1.5-fold). AVP receptor expression levels in these tumors were quantified using quantitative RT-PCR and immunohistochemistry. AVP receptor promoter activity was analyzed using a dual-luciferase reporter assay system. RESULTS: Females (96.9%) and USP8 mutants (85.7%) were more prevalent in the DDAVP test (+) than in the DDAVP test (-). Indeed, the ACTH and cortisol responsiveness to DDAVP was greater in USP8 mutation positive tumors than that in USP8 wild type tumors (3.0-fold vs. 1.3-fold, 1.6-fold vs. 1.1-fold, respectively). Responsiveness to DDAVP was correlated with the expression levels of AVPR1B, but not with those of AVPR2. Comparably, Avpr1b promoter activity was enhanced by the overexpression of mutant USP8 compared to the wild type. CONCLUSIONS: We found that the responsiveness of ACTH to DDAVP in CD was greater in tumors with USP8 mutations. The present data suggest that USP8 mutations upregulate the AVPR1B promoter activity. Additionally, we showed that the DDAVP test can predict the presence of USP8 mutations.

Relation between the insulin lowering rate and changes in bone mineral density: Analysis among subtypes of type 1 diabetes mellitus.

AIMS/INTRODUCTION: The bone mineral density in patients with type 1 diabetes mellitus is reduced due to impaired insulin secretion. However, it is unclear whether the rate of bone mineral density reduction is affected by the type 1 diabetes mellitus subtype. This study aimed to clarify the difference in bone mineral density across type 1 diabetes mellitus subtypes: slowly progressive (SP), acute-onset (AO), and fulminant (F). METHODS: This was a retrospective, single-center, cross-sectional study conducted on 98 adult type 1 diabetes mellitus patients. The main outcome included the bone mineral density Z-score (BMD-Z) measured at the lumbar spine and femoral neck. RESULTS: The lumbar spine BMD-Z was lower in the acute-onset than in the slowly progressive subtype (P = 0.03). No differences were observed when compared with the fulminant subtype. The femoral neck BMD-Z tended to be higher in the slowly progressive than in the acute-onset and fulminant subtypes. Multiple regression analyses showed that the lumbar spine BMD-Z was associated with subtypes (AO vs SP) (P = 0.01), but not subtypes (F vs SP), adjusted for sex, duration, retinopathy, and C-peptide immunoreactivity (CPR). When the patients were divided into disease duration tertiles, in the first and second tertiles, the CPR levels were lower in the acute-onset or fulminant than in the slowly progressive subtype. In contrast, the lumbar spine and femoral neck BMD-Z differed between the acute-onset and slowly progressive only in the second tertiles (both P < 0.01), with a similar tendency between the fulminant and slowly progressive subtypes. CONCLUSIONS: Among the type 1 diabetes mellitus subtypes, bone mineral density undergoes time-dependent changes, which reveals that the bone mineral density decline follows the impaired insulin secretion. These results provide novel insights into the association between the low insulin exposure duration and bone mineral density.

The Effect of Aging on Quality of Life in Acromegaly Patients Under Treatment.

Context: With the increasing number of older patients with acromegaly, it is important to understand the effects of aging on the quality of life (QoL) in acromegaly. Objective: To investigate the factors associated with the QoL of older acromegaly patients. Design: This was a single-center, retrospective, cross-sectional study conducted between 2014 and 2019. Methods: Among 90 acromegaly patients at Kobe University Hospital, 74 who had completed the QoL evaluation under treatment were enrolled (age = 62.0 [50.7-70.0], female 52%). SF-36 and the AcroQoL questionnaire were used to quantify QoL. The patients were divided into two groups: the young and middle-aged group, aged <65 years (51.0 [46.0-59.2], n =42), and the older group, aged ≥65 years (70.5 [69.0-73.0], n =32). The factors associated with the QoL scores were analyzed using univariate and multivariate regression analyses. Results: The scores for the physical component summary of SF-36 were negatively associated with age (P <0.01), while those for the mental or role/social component summary were positively associated (P <0.01, P =0.03, respectively). In contrast, AcroQoL scores were not associated with age. However, the different factors were associated with lower AcroQoL scores; arthropathy and higher BMI in the older group (P <0.01, and P =0.01, respectively), and treatment modalities and size of pituitary tumor in the young and middle-aged group (P <0.01, P =0.04, respectively). Replacement of hydrocortisone was commonly associated both in young and middle-aged group (P =0.04), and in older group (P =0.02). Conclusion: We showed that the factors associated with impaired QoL differed in the young and middle-aged, and older patients with acromegaly. In older patients, arthropathy and higher BMI were associated with poor QoL. These suggest the importance of early diagnosis and appropriate treatment in preventing arthropathy in acromegaly.

Case report: Late middle-aged features of FAM111A variant, Kenny-Caffey syndrome type 2-suggestive symptoms during a long follow-up.

Kenny-Caffey syndrome type 2 (KCS2) is an extremely rare skeletal disorder involving hypoparathyroidism and short stature. It has an autosomal dominant pattern of inheritance and is caused by variants in the FAM111 trypsin-like peptidase A (FAM111A) gene. This disease is often difficult to diagnose due to a wide range of more common diseases manifesting hypoparathyroidism and short stature. Herein, we present the case of a 56-year-old female patient with idiopathic hypoparathyroidism and a short stature. The patient was treated for these conditions during childhood. Upon re-evaluating the etiology of KCS2, we suspected that the patient had the disorder because of clinical manifestations, such as cortical thickening and medullary stenosis of the bones, and lack of intellectual abnormalities. Genetic testing identified a heterozygous missense variant in the FAM111A gene (p.R569H). Interestingly, the patient also had bilateral sensorineural hearing loss and vestibular dysfunction, which have been rarely described in previous reports of pediatric cases. In KCS2, inner ear dysfunction due to Eustachian tube dysfunction may progress in middle age or later. However, this disease is now being reported in younger patients. Nevertheless, our case may be instructive of how such cases emerge chronically after middle age. Herein, we also provide a literature review of KCS2.

Mechanistic insights into immune checkpoint inhibitor-related hypophysitis: a form of paraneoplastic syndrome.

BACKGROUND: Immune checkpoint inhibitors (ICIs) as a cancer immunotherapy have emerged as a treatment for multiple advanced cancer types. Because of enhanced immune responses, immune-related adverse events (irAEs), including endocrinopathies such as hypophysitis, have been associated with the use of ICIs. Most underlying mechanisms of ICI-related hypophysitis remain unclear, especially for programmed cell death-1 (PD-1)/PD-1 ligand 1 (PD-L1) inhibitors. We hypothesized that ICI-related hypophysitis is associated with paraneoplastic syndrome caused by ectopic expression of pituitary-specific antigens. METHODS: Twenty consecutive patients with ICI-related hypophysitis between 2017 and 2019 at Kobe University Hospital were retrospectively analyzed. Circulating anti-pituitary antibodies were detected using immunofluorescence staining and immunoblotting. Ectopic expression of pituitary autoantigens in tumor specimens was also examined. RESULTS: Eighteen patients were treated with PD-1/PD-L1 inhibitors, and two were treated with a combination of cytotoxic T-lymphocyte antigen-4 (CTLA-4) and PD-1 inhibitors. All patients showed adrenocorticotropic hormone (ACTH) deficiency and additionally, three showed thyroid-stimulating hormone (TSH) deficiency, and one showed gonadotropin-releasing hormone (GnRH) deficiency. Among these patients, three exhibited anti-pituitary antibodies, two with anti-corticotroph antibody and one with anti-somatotroph antibody. Interestingly, the anti-corticotroph antibody recognized proopiomelanocortin (POMC) and those two patients exhibited ectopic ACTH expression in the tumor, while the patients without anti-corticotroph antibody did not. CONCLUSIONS: We demonstrated 10% of PD-1/PD-L1 inhibitors-related hypophysitis were associated with the autoimmunity against corticotrophs and maybe caused as a form of paraneoplastic syndrome, in which ectopic expression of ACTH in the tumor was observed. It is also suggested that the pathophysiology is heterogenous in ICI-related hypophysitis.

Clinical Heterogeneity of Acquired Idiopathic Isolated Adrenocorticotropic Hormone Deficiency.

Objective: Heterogeneous clinical characteristics are observed in acquired isolated adrenocorticotropic hormone (ACTH) deficiency (IAD); however, its classification remains to be established because of its largely unknown pathophysiology. In IAD, anti-pituitary antibodies have been detected in some patients, although their significance remains unclear. Therefore, this study aimed to classify patients with IAD and to clarify the significance of anti-pituitary antibodies. Design and Methods: We analyzed 46 consecutive patients with IAD. Serum anti-pituitary antibodies were analyzed via immunofluorescence staining using a mouse pituitary tissue. Principal component and cluster analyses were performed to classify IAD patients based on clinical characteristics and autoantibodies. Results: Immunofluorescence analysis using the sera revealed that 58% of patients showed anti-corticotroph antibodies and 6% of patients showed anti-follicular stellate cell (FSC) antibodies. Principal component analysis demonstrated that three parameters could explain 70% of the patients. Hierarchical cluster analysis showed three clusters: Groups A and B comprised patients who were positive for anti-corticotroph antibodies, and plasma ACTH levels were extremely low. Groups A and B comprised middle-aged or elderly men and middle-aged women, respectively. Group C comprised patients who were positive for the anti-FSC antibody and elderly men; plasma ACTH levels were relatively high. Conclusions: Patients with IAD were classified into three groups based on clinical characteristics and autoantibodies. The presence of anti-corticotroph antibody suggested severe injury to corticotrophs. This new classification clearly demonstrated the heterogeneity in the pathogenesis of IAD.

Two Cases of anti-PIT-1 Hypophysitis Exhibited as a Form of Paraneoplastic Syndrome not Associated With Thymoma.

Anti-pituitary-specific transcription factor 1 (PIT-1) hypophysitis (anti-PIT-1 antibody syndrome) is a thymoma-associated autoimmune disease characterized by acquired growth hormone (GH), prolactin (PRL), and thyrotropin (TSH) deficiencies due to autoimmunity against PIT-1. Ectopic expression of PIT-1 in the thymoma plays a causal role in development of the disease. Here, we report 2 cases of anti-PIT-1 hypophysitis exhibiting as a form of paraneoplastic syndrome with conditions other than thymoma. A 79-year-old woman (case 1) and an 86-year-old man (case 2) were referred with a suspicion of anti-PIT-1 hypophysitis because of acquired GH, PRL, and TSH deficiencies. Case 1 was complicated by diffuse large B-cell lymphoma (DLBCL) of the bladder and case 2 was diagnosed with malignancy with multiple metastases of unknown origin. Because circulating anti-PIT-1 antibody was detected, both patients were diagnosed with anti-PIT-1 hypophysitis. Circulating PIT-1-reactive T cells were detected in case 1 via enzyme-linked immunospot (ELISPOT) assay. Interestingly, the PIT-1 protein was ectopically expressed in the DLBCL cells of case 1, whereas DLBCL tissues derived from patients without anti-PIT-1 hypophysitis were negative for PIT-1. In case 2, the materials were not available because of best supportive care was under way. These data show that anti-PIT-1 hypophysitis is associated not only with thymoma but also with other malignancies. Additionally, the ectopic expression of PIT-1 in the DLBCL tissues and presence of PIT-1-reactive T cells suggested that the underlying mechanisms were similar to those observed in thymoma. Thus, anti-PIT-1 hypophysitis is defined as a form of paraneoplastic syndrome.