Nivolumab-induced Myositis and Myocarditis with Positive Anti-titin Antibody and Anti-voltage-gated Potassium Channel Kv1.4 Antibody

The Current and Future of Biomarkers of Immune Related Adverse Events

With their groundbreaking clinical responses, immune checkpoint inhibitors (ICIs) have ushered in a new chapter in cancer therapeutics. However, they are often associated with life-threatening or organ-threatening autoimmune/autoinflammatory phenomena, collectively termed immune-related adverse events (irAEs). In this review, we will first describe the mechanisms of action of ICIs as well as irAEs. Next, we will review biomarkers for predicting the development of irAEs or stratifying risks.

Pembrolizumab-induced Myopathy with Anti-striated Muscle Antibodies Successfully Treated by Plasma Exchange

A 70-year-old woman with advanced endometrial cancer developed right ptosis and muscle weakness in the right quadriceps after pembrolizumab administration. Serum creatine kinase (CK) levels were elevated, and anti-striated muscle antibodies were positive. On magnetic resonance imaging, the right vastus lateral muscle showed an abnormal signal. She was diagnosed with pembrolizumab-induced myopathy. We initiated plasma exchange (PE), and the ptosis immediately resolved. We then introduced oral corticosteroids, which improved her muscle weakness. We were able to rapidly diagnose her with ocular symptoms and serum CK level elevation. The early initiation of PE might prevent the exacerbation of pembrolizumab-induced myopathy.

Drug therapy for myocarditis induced by immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs), including cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death 1 (PD-1), and its ligand 1 (PD-L1), have improved the survival in multiple types of cancers; however, ICIs may cause cardiovascular toxicity. Although rare, ICI-mediated cardiotoxicity is an extremely serious complication with a relatively high mortality. In this review, we discuss the underlying mechanism and clinical manifestations of cardiovascular toxicity induced by ICIs. According to previous studies, multiple signaling pathways are involved in myocarditis induced by ICIs. Further, we summarize the clinical trials of drugs for the treatment of ICI-associated myocarditis. Although these drugs have shown the beneficial effects of alleviating cardiac function and reducing mortality rates, their efficacy is not optimal. Finally, we discuss the therapeutic potential of some novel compounds as well as the underlying mechanisms of their action.

Myocardial Inflammation as a Manifestation of Genetic Cardiomyopathies: From Bedside to the Bench

Over recent years, preclinical and clinical evidence has implicated myocardial inflammation (M-Infl) in the pathophysiology and phenotypes of traditionally genetic cardiomyopathies. M-Infl resembling myocarditis on imaging and histology occurs frequently as a clinical manifestation of classically genetic cardiac diseases, including dilated and arrhythmogenic cardiomyopathy. The emerging role of M-Infl in disease pathophysiology is leading to the identification of druggable targets for molecular treatment of the inflammatory process and a new paradigm in the field of cardiomyopathies. Cardiomyopathies constitute a leading cause of heart failure and arrhythmic sudden death in the young population. The aim of this review is to present, from bedside to bench, the current state of the art about the genetic basis of M-Infl in nonischemic cardiomyopathies of the dilated and arrhythmogenic spectrum in order to prompt future research towards the identification of novel mechanisms and treatment targets, with the ultimate goal of lowering disease morbidity and mortality.

Anti-Kv1.4 Antibody Without Myasthenia Gravis: A Rare Cause of Autoimmune Myocarditis and Myositis

Anti-Kv1.4 antibody is often detected in thymoma-associated myasthenia gravis patients with anti-acetylcholine receptor antibody. Herein, we describe 2 patients with concurrent myocarditis and myositis. In both cases, anti-Kv1.4 antibody was positive despite the absence of thymoma and anti-acetylcholine receptor antibody, and immunosuppressants eventually resolved their symptoms and cardiac function. (Level of Difficulty: Advanced.).