Myocarditis in systemic immune-mediated diseases: Prevalence, characteristics and prognosis. A systematic review

Autoimmune Myocarditis, Old Dogs and New Tricks

Autoimmunity significantly contributes to the pathogenesis of myocarditis, underscored by its increased frequency in autoimmune diseases such as systemic lupus erythematosus and polymyositis. Even in cases of myocarditis caused by viral infections, dysregulated immune responses contribute to pathogenesis. However, whether triggered by existing autoimmune conditions or viral infections, the precise antigens and immunologic pathways driving myocarditis remain incompletely understood. The emergence of myocarditis associated with immune checkpoint inhibitor therapy, commonly used for treating cancer, has afforded an opportunity to understand autoimmune mechanisms in myocarditis, with autoreactive T cells specific for cardiac myosin playing a pivotal role. Despite their self-antigen recognition, cardiac myosin-specific T cells can be present in healthy individuals due to bypassing the thymic selection stage. In recent studies, novel modalities in suppressing the activity of pathogenic T cells including cardiac myosin-specific T cells have proven effective in treating autoimmune myocarditis. This review offers an overview of the current understanding of heart antigens, autoantibodies, and immune cells as the autoimmune mechanisms underlying various forms of myocarditis, along with the latest updates on clinical management and prospects for future research.

The Role of the Immune System in Pathobiology and Therapy of Myocarditis: A Review

The role of the immune system in myocarditis onset and progression involves a range of complex cellular and molecular pathways. Both innate and adaptive immunity contribute to myocarditis pathogenesis, regardless of its infectious or non-infectious nature and across different histological and clinical subtypes. The heterogeneity of myocarditis etiologies and molecular effectors is one of the determinants of its clinical variability, manifesting as a spectrum of disease phenotype and progression. This spectrum ranges from a fulminant presentation with spontaneous recovery to a slowly progressing, refractory heart failure with ventricular dysfunction, to arrhythmic storm and sudden cardiac death. In this review, we first examine the updated definition and classification of myocarditis at clinical, biomolecular and histopathological levels. We then discuss recent insights on the role of specific immune cell populations in myocarditis pathogenesis, with particular emphasis on established or potential therapeutic applications. Besides the well-known immunosuppressive agents, whose efficacy has been already demonstrated in human clinical trials, we discuss the immunomodulatory effects of other drugs commonly used in clinical practice for myocarditis management. The immunological complexity of myocarditis, while presenting a challenge to simplistic understanding, also represents an opportunity for the development of different therapeutic approaches with promising results.

Myocarditis in connective tissue diseases: an often-overlooked clinical manifestation

To discuss what is currently known about myocarditis in the context of major connective tissue diseases, including Systemic lupus erythematosus, Rheumatoid Arthritis, Sjogren, Dermato-myositis and Polymyositis, Systemic Sclerosis, and Mixed connective tissue disease. Variability exists between studies regarding the incidence of myocarditis in connective tissue diseases, which is hypothesized to be the result of its subclinical course in most cases. Extensive gaps of knowledge exist in the field of pathophysiology. Although endomyocardial biopsy remains to be the gold standard for diagnosis, the advancement in non-invasive modalities such as cardiac MRI, echocardiography, and nuclear medicine has allowed for earlier and more frequent detection of myocarditis. A lack of treatment guidelines was found across the different connective tissue diseases. Most of the literature available revolved around myocarditis in the context of Systemic lupus erythematosus. Numerous recent studies were published that contributed to advancements in diagnosis and treatment however, there remains a lack of diagnostic and treatment guidelines.

Immunopathogenesis and immunomodulatory therapy for myocarditis

Myocarditis is an inflammatory cardiac disease characterized by the destruction of myocardial cells, infiltration of interstitial inflammatory cells, and fibrosis, and is becoming a major public health concern. The aetiology of myocarditis continues to broaden as new pathogens and drugs emerge. The relationship between immune checkpoint inhibitors, severe acute respiratory syndrome coronavirus 2, vaccines against coronavirus disease-2019, and myocarditis has attracted increased attention. Immunopathological processes play an important role in the different phases of myocarditis, affecting disease occurrence, development, and prognosis. Excessive immune activation can induce severe myocardial injury and lead to fulminant myocarditis, whereas chronic inflammation can lead to cardiac remodelling and inflammatory dilated cardiomyopathy. The use of immunosuppressive treatments, particularly cytotoxic agents, for myocarditis, remains controversial. While reasonable and effective immunomodulatory therapy is the general trend. This review focuses on the current understanding of the aetiology and immunopathogenesis of myocarditis and offers new perspectives on immunomodulatory therapies.

Fulminant Myocarditis: When One Size Does Not Fit All - A Critical Review of the Literature

Fulminant myocarditis, rather than being a distinct form of myocarditis, is instead a peculiar clinical presentation of the disease. The definition of fulminant myocarditis has varied greatly in the last 20 years, leading to conflicting reports on prognosis and treatment strategies, mainly because of varied inclusion criteria in different studies. The main conclusion of this review is that fulminant myocarditis may be due to different histotypes and aetiologies that can be diagnosed only by endomyocardial biopsy and managed by aetiology-directed treatment. This life-threatening presentation requires rapid, targeted management both in the short term (mechanical circulatory support, inotropic and antiarrhythmic treatment and endomyocardial biopsy) and in the long term (including prolonged follow-up). Fulminant presentation has also recently been identified as a risk factor for worsened prognosis, even long after the resolution of the acute phase of myocarditis.

Myocarditis and inflammatory bowel diseases: A single-center experience and a systematic literature review

BACKGROUND

Myocarditis and inflammatory bowel diseases (IBD) are rare conditions, but may coexist. Myocarditis in IBD may be infective, immune-mediated, or due to mesalamine toxicity. A gap of knowledge exists on the clinical features of patients that present myocarditis in association with IBD, especially for endomyocardial biopsy-proven cases. Our aims are: 1) to describe the clinical characteristics of patients with an associated diagnosis of myocarditis and IBD in a single-center hospital, 2) to perform a systematic review of the literature of analogous cases.

METHODS

We retrospectively analyzed data of patients followed up at the outpatient Cardio-immunology and Gastroenterology Clinic of Padua University Hospital, to identify those with an associated diagnosis of myocarditis and IBD. In addition, a systematic review of the literature was conducted. We performed a qualitative analysis of the overall study population.

RESULTS

The study included 104 patients (21 from our single center cohort, 83 from the literature review). Myocarditis in IBD more frequently affects young (median age 31 years) males (72%), predominantly with infarct-like presentation (58%), within an acute phase of the IBD (67%) and with an overall benign clinical course (87%). Nevertheless, a not negligible quote of patients may present giant cell myocarditis, deserve immunosuppression and have a chronic, or even fatal course. Histological evidence of mesalamine hypersensitivity is scarce and its incidence may be overestimated.

CONCLUSIONS

Our study shows that myocarditis in association with IBD, if correctly managed, may have a spontaneous benign course, but predictors of worse prognosis must be promptly recognized.

Safety of COVID-19 Vaccines in Patients with Autoimmune Diseases, in Patients with Cardiac Issues, and in the Healthy Population

The coronavirus disease 2019 (COVID-19) has been a challenge for the whole world since the beginning of 2020, and COVID-19 vaccines were considered crucial for disease eradication. Instead of producing classic vaccines, some companies pointed to develop products that mainly function by inducing, into the host, the production of the antigenic protein of SARS-CoV-2 called Spike, injecting an instruction based on RNA or a DNA sequence. Here, we aim to give an overview of the safety profile and the actual known adverse effects of these products in relationship with their mechanism of action. We discuss the use and safety of these products in at-risk people, especially those with autoimmune diseases or with previously reported myocarditis, but also in the general population. We debate the real necessity of administering these products with unclear long-term effects to at-risk people with autoimmune conditions, as well as to healthy people, at the time of omicron variants. This, considering the existence of therapeutic interventions, much more clearly assessed at present compared to the past, and the relatively lower aggressive nature of the new viral variants.

Scleromyositis: A distinct novel entity within the systemic sclerosis and autoimmune myositis spectrum. Implications for care and pathogenesis

Systemic sclerosis and autoimmune myositis are both associated with decreased quality of life and increased mortality. Their prognosis and management largely depend on the disease subgroups. Indeed, systemic sclerosis is a heterogeneous disease, the two predominant forms of the disease being limited and diffuse scleroderma. Autoimmune myositis is also a heterogeneous group of myopathies that classically encompass necrotizing myopathy, antisynthetase syndrome, dermatomyositis and inclusion body myositis. Recent data revealed that an additional disease subset, denominated "scleromyositis", should be recognized within both the systemic sclerosis and the autoimmune myositis spectrum. We performed an in-depth review of the literature with the aim of better delineating scleromyositis. Our review highlights that this concept is supported by recent clinical, serological and histopathological findings that have important implications for patient management and understanding of the disease pathophysiology. As compared with other subsets of systemic sclerosis and autoimmune myositis, scleromyositis patients can present with a characteristic pattern of muscle involvement (i.e. distribution of muscle weakness) along with multisystemic involvement, and some of these extra-muscular complications are associated with poor prognosis. Several autoantibodies have been specifically associated with scleromyositis, but they are not currently integrated in diagnostic and classification criteria for systemic sclerosis and autoimmune myositis. Finally, striking vasculopathic lesions at muscle biopsy have been shown to be hallmarks of scleromyositis, providing a strong anatomopathological substratum for the concept of scleromyositis. These findings bring new insights into the pathogenesis of scleromyositis and help to diagnose this condition, in patients with subtle SSc features and/or no autoantibodies (i.e. "seronegative" scleromyositis). No guidelines are available for the management of these patients, but recent data are showing the way towards a new therapeutic approach dedicated to these patients.

Cardiac Safety of mRNA-Based Vaccines in Patients with Systemic Lupus Erythematosus and Lupus-like Disorders with a History of Myocarditis

Anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may trigger immune-mediated adverse events, including myocarditis. Evidence of vaccine safety in patients with rheumatic disorders and underlying autoimmune myocarditis is scarce. To address this issue, we studied 13 patients with systemic lupus erythematosus (SLE) and allied conditions with a history of myocarditis and receiving mRNA-based vaccines. Data about general and cardiac laboratory tests, treatment, and disease status were collected during routine consultations before and after the primary vaccination course and after each vaccine dose administration, while myocarditis symptoms were closely monitored. A significant increase in troponin levels from baseline was found after 13 (6–20) days from the first (p = 0.046) and 17 (4–29) days after the second dose (p = 0.013). Troponin levels progressively decreased within 3 (1–6) months in the absence of typical symptoms or signs of myocarditis. A significant increase in the constitutional domain of the British Isles Lupus Assessment Group (BILAG) index (p = 0.046) was observed in SLE patients. However, no patient needed any treatment change. mRNA-based anti-SARS-CoV-2 vaccines can apparently be safely administered to patients with SLE and lupus-like disorders with previous myocarditis despite potential subclinical and transient rises in cardiac damage markers.

Role of Endomyocardial Biopsy in Diagnostics of Myocarditis

Endomyocardial biopsy as the cornerstone of diagnostics has been re-evaluated throughout the years, leaving unanswered questions on the precedence of it. The reported incidence of myocarditis has increased during the pandemic of coronavirus disease 2019 (COVID-19), reinforcing discussions on appropriate diagnostics of myocarditis. By analysis of evidence-based literature published within the last demi-decade, we aimed to summarize the most recent information in order to evaluate the current role of endomyocardial biopsy in diagnostics and management of myocarditis. For the most part, research published over the last five years showed ongoing uncertainty regarding the use, informativeness, safety and necessity of performing a biopsy. Special circumstances, such as fulminant clinical course or failure to respond to empirical treatment, were reconfirmed as justified indications, with a growing applicability of non-invasive diagnostic approaches for most other cases. We concluded that endomyocardial biopsy, if performed properly and with adjunct diagnostic methods, holds a critical role for treatment correction in specific histological subtypes of myocarditis and for differential diagnosis between immune-mediated myocarditis and secondary infections due to immunosuppressive treatment. A high level of possible misdiagnosing was detected, indicating the need to review terminology used to describe findings of myocardial inflammation that did not meet Dallas criteria.

The mosaic of autoimmunity - Finally discussing in person. The 13th international congress on autoimmunity 2022 (AUTO13) Athens

While autoimmunity is a branch of medicine linked to every single organ system via direct and indirect pathways, meeting in person to discuss autoimmunity during the 13^th international congress on autoimmunity (AUTO13) with participants from all over the world had a very good reason. The mechanisms involved in autoimmune diseases are of extreme importance and in fact critical in understanding the course of diseases as well as selecting proper therapies. COVID-19 has served as a great example of how autoimmunity is deeply involved in the disease and directly correlated to severity, morbidity, and mortality. For instance, initially the term cytokine storm dominated, then COVID-19 was addressed as the new member of the hyperferritinemic syndrome, and also the use of immunosuppressants in patients with COVID-19 throughout the pandemic, all shed light on the fundamental role of autoimmunity. Unsurprisingly, SARS-CoV-2 was called the “autoimmune virus” during AUTO13. Subsequently, the correlation between autoimmunity and COVID-19 vaccines and post-COVID, all were discussed from different autoimmune aspects during the congress. In addition, updates on the mechanisms of diseases, autoantibodies, novel diagnostics and therapies in regard to autoimmune diseases such as antiphospholipid syndrome, systemic lupus erythematosus, systemic sclerosis and others, were discussed in dedicated sessions. Due to the magnificence of the topics discussed, we aimed to bring in our article hereby, the pearls of AUTO13 in terms of updates, new aspects of autoimmunity, and interesting findings. While more than 500 abstract were presented, concluding all the topics was not in reach, hence major findings were summarized.