Small steps for idiopathic giant cell myocarditis

Inhibition of NETosis via PAD4 alleviated inflammation in giant cell myocarditis

Giant cell myocarditis (GCM) is a rare, usually rapidly progressive, and potentially fatal disease. Detailed inflammatory responses remain unknown, in particular the formation of multinucleate giant cells. We performed single-cell RNA sequencing analysis on 15,714 Cd45+ cells extracted from the hearts of GCM rats and normal rats. NETosis has been found to contribute to the GCM process. An inhibitor of NETosis, GSK484, alleviated GCM inflammation in vivo. MPO (a marker of neutrophils) and H3cit (a marker of NETosis) were expressed at higher levels in patients with GCM than in patients with DCM and healthy controls. Imaging mass cytometry analysis revealed that immune cell types within multinucleate giant cells included CD4+ T cells, CD8+ T cells, neutrophils, and macrophages but not B cells. We elucidated the role of NETosis in GCM pathogenesis, which may serve as a potential therapeutic target in the clinic.

Giant cell myositis and myocarditis revisited

Giant cell myositis (GCMm) and giant cell myocarditis (GCMc) are two rare autoimmune conditions. Among these, GCMc is a life-threatening disease with a 1-year mortality rate of 70%. Lethal ventricular arrhythmias, rapid evolution to heart failure and sudden death risk makes GCMc an emergency condition. It is thought to be mediated by T-cells and characterized by the presence of myofiber necrosis and giant cells in biopsies. Most commonly co-manifesting conditions with GCMm and/or GCMc are thymoma, myasthenia gravis and orbital myositis, all of which are treatable. As suspicion is the key approach in diagnosis, the physician following patients with thymoma with or without myasthenia gravis and with orbital myositis should always be alert. The fatal nature of GCMc associated with these relatively benign diseases deserves a special emergency attention with prompt institution of combined immunosuppressive treatment and very early inclusion of heart failure teams.

Evaluation of Myocardial Gene Expression Profiling for Superior Diagnosis of Idiopathic Giant-Cell Myocarditis and Clinical Feasibility in a Large Cohort of Patients with Acute Cardiac Decompensation

Aims: The diagnostic approach to idiopathic giant-cell myocarditis (IGCM) is based on identifying various patterns of inflammatory cell infiltration and multinucleated giant cells (GCs) in histologic sections taken from endomyocardial biopsies (EMBs). The sampling error for detecting focally located GCs by histopathology is high, however. The aim of this study was to demonstrate the feasibility of gene profiling as a new diagnostic method in clinical practice, namely in a large cohort of patients suffering from acute cardiac decompensation. Methods and Results: In this retrospective multicenter study, EMBs taken from n = 427 patients with clinically acute cardiac decompensation and suspected acute myocarditis were screened (mean age: 47.03 ± 15.69 years). In each patient, the EMBs were analyzed on the basis of histology, immunohistology, molecular virology, and gene-expression profiling. Out of the total of n = 427 patient samples examined, GCs could be detected in 26 cases (6.1%) by histology. An established myocardial gene profile consisting of 27 genes was revealed; this was narrowed down to a specified profile of five genes (CPT1, CCL20, CCR5, CCR6, TLR8) which serve to identify histologically proven IGCM with high specificity in 25 of the 26 patients (96.2%). Once this newly established profiling approach was applied to the remaining patient samples, an additional n = 31 patients (7.3%) could be identified as having IGCM without any histologic proof of myocardial GCs. In a subgroup analysis, patients diagnosed with IGCM using this gene profiling respond in a similar fashion to immunosuppressive therapy as patients diagnosed with IGCM by conventional histology alone. Conclusions: Myocardial gene-expression profiling is a promising new method in clinical practice, one which can predict IGCM even in the absence of any direct histologic proof of GCs in EMB sections. Gene profiling is of great clinical relevance in terms of (a) overcoming the sampling error associated with purely histologic examinations and (b) monitoring the effectiveness of therapy.

Management of a patient presenting with giant cell myocarditis - A case report

Giant cell myocarditis is a rare and frequently fatal disease that requires extensive cardiac care. Given the rarity of this condition no specific management recommendations exist. We describe a patient who presented with congestive heart failure that required a left ventricular assist device and a temporary right ventricular assist device along with immunosuppressive therapy. This case also brings to attention how undocumented immigration status can limit transplantation opportunities in the USA. <Learning objective: Giant cell myocarditis is a rare and frequently fatal cardiac disease that, until the 1980s, was only diagnosed during autopsy. It is commonly seen in young and middle-aged, otherwise healthy, individuals with median transplant-free survival of 5.5 months from diagnosis. Current treatments with immunosuppressant medications do not seem to be significantly effective. Most patients require transplant or ventricular assist device for survival.>.

Genetic Basis of Myocarditis: Myth or Reality?

The genetic basis of myocarditis remains an intriguing concept, at least as long as the definition of myocarditis constitutes the definitive presence of myocardial inflammation sufficient to cause the observed ventricular dysfunction in the setting of cardiotropic infections. Autoimmune or immune-mediated myocardial inflammation constitutes a complex area of clinical interest, wherein numerous and not yet fully understood role of hereditary auto-inflammatory diseases can result in inflammation of the pericardium and myocardium. Finally, myocardial involvement in hereditary immunodeficiency diseases, cellular and humoral, is a possible trigger for infections which may complicate the diseases themselves. Whether the role of constitutional genetics can make the patient susceptible to myocardial inflammation remains yet to be explored.

Successful Triple Combination Immunosuppressive Therapy with Prednisolone, Cyclosporine, and Mycophenolate Mofetil to Treat Recurrent Giant Cell Myocarditis

A 59-year-old man with a history of giant cell myocarditis was admitted to our hospital with recurrent giant cell myocarditis triggered by a 1 mg/day taper in his prednisolone dose. During the initial episode, he had undergone rescue implantation of a temporary left ventricular assist device followed by the administration of dual immunosuppressive therapy with prednisolone and concomitant cyclosporine. Triple combination immunosuppressive therapy maintained with additional mycophenolate mofetil successfully controlled recurrent myocarditis, enabled a reduction in the prednisolone dose, and achieved the functional recovery of the left ventricle.

Giant cell myocarditis: a life-threatening disorder heralded by orbital myositis

A 40-year-old man with a history of orbital myositis (OM) presented to the emergency department with ventricular tachycardia requiring electrical cardioversion. Postcardioversion ECG showed right bundle branch block, while an echocardiogram revealed an ejection fraction of 20% and a dilated right ventricle. Cardiac MRI produced suboptimal images because the patient was having frequent arrhythmias. The rest of the work up, including coronary angiography, was unremarkable. Given the dilated right ventricle, we suspected arrhythmogenic right ventricular cardiomyopathy and discharged the patient with an implantable cardioverter-defibrillator. 1 week later, he was readmitted with cardiogenic shock; endomyocardial biopsy revealed giant cell myocarditis (GCM). To the best of our knowledge, this is the seventh case report of GCM described in a patient with OM. We recommend that clinicians maintain a high degree of suspicion for GCM in patients with OM presenting with cardiac problems.