Severe Hyponatremia Triggered by Immune Checkpoint Inhibitor Therapy in a Patient With Mulvihill-Smith Syndrome.

Background/Objective: Immune checkpoint inhibitors (ICI), including Programmed Cell Death 1, Programmed Cell Death Ligand 1, and Cytotoxic T-lymphocyte Associated Antigen 4 inhibitors, upregulate T-cell responses against tumor cells and are becoming a cornerstone in the treatment of various advanced solid and hematological cancers. Mulvihill-Smith Syndrome (MSS) is a rare genetic syndrome that has been associated with metabolic abnormalities and early-onset tumors, including malignancies. We report the first known case of ICI-induced hyponatremia attributable to syndrome of inappropriate antidiuretic hormone ADH release (SIADH) in a patient with MSS. Case Report: A 23-year-old female patient with MSS and hepatocellular carcinoma presented with recurrent hyponatremia. Assessment of fluid status and electrolytes revealed a euvolemic, hypotonic process consistent with SIADH shortly after initiating adjuvant therapy with atezolizumab, a Programmed Cell Death Ligand 1 inhibitor. Discussion: Endocrine etiologies for euvolemic hypotonic hyponatremia, including adrenal insufficiency and hypothyroidism, were excluded. The diagnosis of SIADH was confirmed based on electrolyte and osmolality studies. Sodium levels normalized with fluid restriction. Given the onset of hyponatremia 30 days after atezolizumab initiation, we posit that atezolizumab triggered severe hyponatremia due to SIADH. Conclusion: With the expanding utilization of ICIs, including in patients predisposed to malignancies such as MSS, vigilant monitoring for ICI-mediated electrolyte imbalances is crucial. Monitoring for hyponatremia and SIADH in the setting of ICI therapy is recommended.

Permanent hypothyroidism following immune checkpoint inhibitors induced thyroiditis may be associated with improved survival: results of an exploratory study.

Background: Immune-related endocrinopathies are common after immune checkpoint inhibitor (ICI) therapy, among which destructive thyroiditis is the most prevalent. Improved survival outcomes have been associated with immune-related adverse events. We aimed to compare the clinical course and biochemical parameters of two subtypes of ICI-related destructive thyroiditis: a transient thyrotoxicosis that reverts to either euthyroidism (TT; transient thyroiditis) versus progression to permanent hypothyroidism (PH), and to identify prognostic markers in cancer patients receiving ICI therapy who developed DT. Methods: This retrospective observational study included 124 patients who developed a transient thyrotoxicosis due to a destructive thyroiditis after ICI therapy from January 1, 2016 to April 30, 2021 at the Montefiore Medical Center. Patients were categorized as either TT or PH based on spontaneous renormalization of the TSH or the permanent need for thyroid hormone replacement, respectively. Thyroid hormone and antibody levels, serum inflammatory markers, eosinophils, and metabolic uptake of the thyroid on PET imaging, each corresponding closest to a suppressed TSH, were characterized. Survival from TT and PH were also analyzed. Results: Of the 124 patients, 53 developed PH and 71 developed TT. The PH group developed thyrotoxicosis at a median of 42 days from the first ICI dose while the TT group took significantly longer at 56 days. Thyroidal PET uptake was increased in 18.9% of the PH group versus 6.0% of the TT group (P=0.04). Three different survival models consistently demonstrated a trend towards increased survival in the PH group, compared to the TT group. Conclusion: Our results suggest that PH developing after ICI-induced destructive thyroiditis may be associated with a more robust inflammatory and antitumor response to ICI therapy. The results suggests that PH may be a potential clinical predictor of improved survival.

Genetics and epigenetics of autoimmune thyroid diseases: Translational implications.

Hashimoto's thyroiditis (HT) and Graves' disease (GD) are prevalent autoimmune disorders, representing opposite ends of the clinical spectrum of autoimmune thyroid diseases (AITD). The pathogenesis involves a complex interplay between environment and genes. Specific susceptibility genes have been discovered that predispose to AITD, including thyroid-specific and immune-regulatory genes. Growing evidence has revealed that genetic and epigenetic variants can alter autoantigen presentation during the development of immune tolerance, can enhance self-peptide binding to MHC (major histocompatibility complex), and can amplify stimulation of T- and B-cells. These gene-driven mechanistic discoveries lay the groundwork for novel treatment targets. This review summarizes recent advances in our understanding of key AITD susceptibility genes (Tg1, TSHR, HLA-DR3, and CD40) and their translational therapeutic potential.

Hyperglycemic Emergencies Associated With COVID-19 Vaccination: A Case Series and Discussion.

CONTEXT: Hyperglycemic emergencies such as diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic syndrome (HHS) and new-onset diabetes mellitus (DM) have been reported in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Hyperglycemia is a predictor of poor prognosis in COVID-19 disease. OBJECTIVES: The objective of this work is to describe a case series of HHS and/or DKA likely triggered by the COVID-19 vaccine. The aim is to alert physicians of the potential hyperglycemic complications from the COVID-19 vaccination and to provide further insight into the underlying mechanism of the bidirectional relationship between SARS-CoV-2 and DM. CASE DESCRIPTIONS: All 3 patients developed HHS and/or DKA within 2 to 10 days of the COVID-19 vaccination. PCR testing for SARS-CoV-2 was negative and other clinical precipitating factors were excluded. Two patients had a history of type 2 DM (T2DM) with pre-admission HbA1c levels of 7.0% to 7.5% while 1 patient was newly diagnosed with T2DM during the hospitalization. They were each treated with insulin infusion and were discharged on subcutaneous insulin therapy. Due to the rapid resolution of the hyperglycemia, insulin was discontinued in all patients within 8 weeks and they remain well-controlled on oral DM medications. CONCLUSION: Severe hyperglycemia including HHS and DKA may be triggered by COVID-19 vaccination. Early evaluation and screening of patients with hyperglycemic symptoms after COVID-19 vaccination is recommended. The vaccine-induced hyperglycemia may provide further insight into the underlying pathogenesis caused by the SARS-CoV-2 infection itself. The underlying robust inflammatory response and "cytokine storm" may be the primary precipitant.

RAPID EVOLUTION OF THYROID DYSFUNCTION IN PATIENTS TREATED WITH NIVOLUMAB.

OBJECTIVE: To describe the evolution of thyroid dysfunction in a series of patients with cancer treated with the immune checkpoint inhibitor anti-programmed cell death protein-1 (PD-1) monoclonal antibody, nivolumab. METHODS: Cases of thyroid dysfunction after initiation of checkpoint inhibitor treatment were identified from the Division of Endocrinology clinical practice at Mount Sinai Hospital, New York from April 2016 to February 2017. Charts were reviewed to identify patients treated with nivolumab with new onset of thyroid dysfunction. RESULTS: Nine cases of thyroid function in patients who were treated with nivolumab were identified. There were 4 male and 5 female patients, with a mean age of 66 years (range 50-76 years). Seven patients ultimately developed hypothyroidism. Five of the 7 patients developed abnormal thyroid function tests within the first 90 days of starting therapy (range 21-84 days), 3 of whom had transient hyperthyroidism. Transient hyperthyroidism evolved rapidly to hypothyroidism; elevated thyroid-stimulating hormone (TSH) levels were detected within 16 to 32 days of the last documented low TSH. In the 2 patients without a hyperthyroid phase, TSH levels >50 were found 18 to 28 days after the last normal TSH value. CONCLUSION: As the use of immune checkpoint inhibitor therapy increases, the need for prompt diagnosis and treatment of drug-induced thyroid disease will become more important. As illustrated in this case series, in contrast to other causes of auto-immune thyroiditis, hypothyroidism can develop rapidly within 3 months of treatment. Close monitoring is necessary to detect the development of thyroid dysfunction and avoid preventable morbidity. ABBREVIATIONS: Anti-TPO Abs = anti-thyroglobulin antibodies; CT = computed tomography; CTLA-4 = cytotoxic T-lymphocyte-associated protein 4; FDA = U.S. Food & Drug Administration; FDG-PET = fluorodeoxyglucose-positron emission tomography; PD-1 = programmed cell death protein-1; PD-L1 = programmed death-ligand 1; T3 = triiodothyronine; T4 = thyroxine; TG = thyroglobulin; TPO = thyroperoxidase; TSH = thyroid-stimulating hormone.

CD40 Signaling in Graves Disease Is Mediated Through Canonical and Noncanonical Thyroidal Nuclear Factor κB Activation.

CD40, a tumor necrosis factor receptor, is a major immune-modulating susceptibility gene for Graves disease (GD) as well as for a variety of other autoimmune diseases. Its broad association with autoimmunity underscores its paramount role in the development of a normal adaptive immune response, primarily in coordinating effective antigen presentation. The molecular pathways by which CD40 activation in the thyroid induces GD are unknown. In this study, we investigated whether NF-κB, a ubiquitious family of transcription factors, mediates the downstream effects of thyroid-specific CD40 activation. Cultured primary human thyrocytes, from patients with and without GD, underwent CD40 stimulation. Once stimulated, cytokines and transcription factors specific for either the canonical nuclear factor κB (NF-κB)1 pathway [interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α], which primarily recruits cells for innate immunity, or the noncanonical NF-κB2 pathway [B cell-activating factor of the TNF family, CC chemokine ligand (CCL)21], which directs B cell viability, were analyzed. Significant upregulation in the messenger RNA and protein levels of both canonical and noncanonical pathway cytokines was observed. Western blot analyses of the specific transcription factors for the NF-κB1 and NF-κB2 pathways (p65 and p100/p52, respectively) demonstrated that p65 is constitutively expressed. In contrast, CD40 stimulation robustly increased the expression of the NF-κB2 p52 transcription factor, and the upregulation was significantly more profound in the GD tissue than in the normal thyroid tissue. Our data show that CD40 activity in thyrocytes is prominently mediated via NF-κB and furthermore suggest that the NF-κB1 and NF-κB2 pathways both contribute to the triggering and the progression of GD.

Hepatitis C Virus E2 Protein Induces Upregulation of IL-8 Pathways and Production of Heat Shock Proteins in Human Thyroid Cells.

Context: Thyroiditis is one of the most common extrahepatic manifestations of hepatitis C virus (HCV) infection. By binding to surface cell receptor CD81, HCV envelope glycoprotein E2 mediates entry of HCV into cells. Studies have shown that different viral proteins may individually induce host responses to infection. We hypothesized that HCV E2 protein binding to CD81 expressed on thyroid cells activates a cascade of inflammatory responses that can trigger autoimmune thyroiditis in susceptible individuals. Setting: Human thyroid cell lines ML-1 and human thyrocytes in primary cell culture were treated with HCV recombinant E2 protein. The expression of major proinflammatory cytokines was measured at the messenger RNA and protein levels. Next-generation transcriptome analysis was used to identify early changes in gene expression in thyroid cells induced by E2. Results: HCV envelope protein E2 induced strong inflammatory responses in human thyrocytes, resulting in production of interleukin (IL)-8, IL-6, and tumor necrosis factor-α. Furthermore, the E2 protein induced production of several heat shock proteins including HSP60, HSP70p12A, and HSP10, in human primary thyrocytes. In thyroid cell line ML-1, RNA sequencing identified upregulation of molecules involved in innate immune pathways with high levels of proinflammatory cytokines and chemokines and increased expression of costimulatory molecules, specifically CD40, known to be a major thyroid autoimmunity gene. Conclusion: Our data support a key role for HCV envelope protein E2 in triggering thyroid autoimmunity through activation of cytokine pathways by bystander mechanisms.

Diabetes and Hepatitis C: A Two-Way Association.

Diabetes and hepatitis C infection are both prevalent diseases worldwide, and are associated with increased morbidity and mortality. Most studies, but not all, have shown that patients with chronic hepatitis C are more prone to develop type 2 diabetes (T2D) compared to healthy controls, as well as when compared to patients with other liver diseases, including hepatitis B. Furthermore, epidemiological studies have revealed that patients with T2D may also be at higher risk for worse outcomes of their hepatitis C infection, including reduced rate of sustained virological response, progression to fibrosis and cirrhosis, and higher risk for development of hepatocellular carcinoma. Moreover, hepatitis C infection and mainly its treatment, interferon α, can trigger the development of type 1 diabetes. In this review, we discuss the existing data on this two-way association between diabetes and hepatitis C infection with emphasis on possible mechanisms. It remains to be determined whether the new curative therapies for chronic hepatitis C will improve outcomes in diabetic hepatitis C patients, and conversely whether treatment with Metformin will reduce complications from hepatitis C virus infection. We propose an algorithm for diabetes screening and follow-up in hepatitis C patients.

Immunogenetics of autoimmune thyroid diseases: A comprehensive review.

Both environmental and genetic triggers factor into the etiology of autoimmune thyroid disease (AITD), including Graves' disease (GD) and Hashimoto's thyroiditis (HT). Although the exact pathogenesis and causative interaction between environment and genes are unknown, GD and HT share similar immune-mediated mechanisms of disease. They both are characterized by the production of thyroid autoantibodies and by thyroidal lymphocytic infiltration, despite being clinically distinct entities with thyrotoxicosis in GD and hypothyroidism in HT. Family and population studies confirm the strong genetic influence and inheritability in the development of AITD. AITD susceptibility genes can be categorized as either thyroid specific (Tg, TSHR) or immune-modulating (FOXP3, CD25, CD40, CTLA-4, HLA), with HLA-DR3 carrying the highest risk. Of the AITD susceptibility genes, FOXP3 and CD25 play critical roles in the establishment of peripheral tolerance while CD40, CTLA-4, and the HLA genes are pivotal for T lymphocyte activation and antigen presentation. Polymorphisms in these immune-modulating genes, in particular, significantly contribute to the predisposition for GD, HT and, unsurprisingly, other autoimmune diseases. Emerging evidence suggests that single nucleotide polymorphisms (SNPs) in the immunoregulatory genes may functionally hinder the proper development of central and peripheral tolerance and alter T cell interactions with antigen presenting cells (APCs) in the immunological synapse. Thus, susceptibility genes for AITD contribute directly to the key mechanism underlying the development of organ-specific autoimmunity, namely the breakdown in self-tolerance. Here we review the major immune-modulating genes that are associated with AITD and their potential functional effects on thyroidal immune dysregulation.