Serum Anti-Heart and Anti-Intercalated Disk Autoantibodies: Novel Autoimmune Markers in Cardiac Sarcoidosis

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.

Advances in myocarditis management in the light of the latest research and recent guidelines of the European Society of Cardiology

Myocarditis remains an unknown disease with varying clinical manifestations, often leading to heart failure. The latest 2021 and 2022 guidelines of the European Society of Cardiology (ESC) are the first official European documents updating knowledge on the diagnosis and treatment of myocarditis since the 2013 ESC expert consensus statement. These guidelines and new studies allow standardization and improvements to the management of myocarditis. In this review, we discuss the most important aspects of myocarditis diagnosis, therapies and follow-up based on current knowledge.

Sarcoidosis-related autoimmune inflammation in COVID-19 convalescent patients

Currently, there are a large number of reports about the development of autoimmune conditions after COVID-19. Also, there have been cases of sarcoid-like granulomas in convalescents as a part of the post-COVID-19 syndrome. Since one of the etiological theories of sarcoidosis considers it to be an autoimmune disease, we decided to study changes in the adaptive humoral immune response in sarcoidosis and SARS-CoV-2 infection and to find out whether COVID-19 can provoke the development of sarcoidosis. This review discusses histological changes in lymphoid organs in sarcoidosis and COVID-19, changes in B cell subpopulations, T-follicular helper cells (Tfh), and T-follicular regulatory cells (Tfr), and analyzes various autoantibodies detected in these pathologies. Based on the data studied, we concluded that SARS-CoV-2 infection may cause the development of autoimmune pathologies, in particular contributing to the onset of sarcoidosis in convalescents.

A Machine-Learning Model for the Prognostic Role of C-Reactive Protein in Myocarditis

Aims: The role of inflammation markers in myocarditis is unclear. We assessed the diagnostic and prognostic correlates of C-reactive protein (CRP) at diagnosis in patients with myocarditis. Methods and results: We retrospectively enrolled patients with clinically suspected (CS) or biopsy-proven (BP) myocarditis, with available CRP at diagnosis. Clinical, laboratory and imaging data were collected at diagnosis and at follow-up visits. To evaluate predictors of death/heart transplant (Htx), a machine-learning approach based on random forest for survival data was employed. We included 409 patients (74% males, aged 37 ± 15, median follow-up 2.9 years). Abnormal CRP was reported in 288 patients, mainly with CS myocarditis (p < 0.001), recent viral infection, shorter symptoms duration (p = 0.001), chest pain (p < 0.001), better functional class at diagnosis (p = 0.018) and higher troponin I values (p < 0.001). Death/Htx was reported in 13 patients, of whom 10 had BP myocarditis (overall 10-year survival 94%). Survival rates did not differ according to CRP levels (p = 0.23). The strongest survival predictor was LVEF, followed by anti-nuclear auto-antibodies (ANA) and BP status. Conclusions: Raised CRP at diagnosis identifies patients with CS myocarditis and less severe clinical features, but does not contribute to predicting survival. Main death/Htx predictors are reduced LVEF, BP diagnosis and positive ANA.

Autoantibody profile in sarcoidosis, analysis from the GRADS sarcoidosis cohort

BACKGROUND

Sarcoidosis, a multi-systemic granulomatous disease, is a predominantly T-cell disease but evidence for a role for humoral immunity in disease pathogenesis is growing. Utilizing samples from the Genomic Research in Alpha-1 anti-trypsin Deficiency and Sarcoidosis (GRADS) study, we examined the prevalence of autoantibodies in sarcoidosis patients with pulmonary-only and extra-pulmonary organ involvement compared to normal controls.

STUDY DESIGN AND METHODS

We analyzed serum samples from sarcoidosis patients who participated in the GRADS study utilizing an autoantigen microarray platform for both IgM and IgG antibodies. The cohort included sarcoidosis patients with pulmonary-only disease (POS, n = 106), sarcoidosis patients with extra-pulmonary disease (EPS, n = 120) and a normal control cohort (NC, n = 101). Organ involvement was assessed following a standardized format across all GRADS participating centers.

RESULTS

Sarcoidosis patients overall had increased levels of IgM and IgG autoantibodies compared to normal controls. In addition, several autoantibodies were elevated in the POS and EPS cohorts compared to the NC cohort. Differences in autoantibody levels were also noted between the POS and the EPS cohorts. When comparing organ involvement with sarcoidosis, bone, spleen and ear, nose and throat involvement had higher IgM expression than other organs.

CONCLUSION

Sarcoidosis patients have elevated IgM and IgG autoantibody levels compared to normal controls. In addition, individuals with pulmonary as well as additional organ involvement had higher IgM expression. Further research is needed focusing on specific organ-autoantibody pairs and role of autoantibodies in disease pathogenesis.

Personalized Management of Myocarditis and Inflammatory Cardiomyopathy in Clinical Practice

Myocarditis is an inflammatory heart disease induced by infectious and non-infectious causes frequently triggering immune-mediated pathologic mechanisms leading to myocardial damage and dysfunction. In approximately half of the patients, acute myocarditis resolves spontaneously while in the remaining cases, it may evolve into serious complications including inflammatory cardiomyopathy, arrhythmias, death, or heart transplantation. Due to the large variability in clinical presentation, unpredictable course of the disease, and lack of established causative treatment, myocarditis represents a challenging diagnosis in modern cardiology. Moreover, an increase in the incidence of myocarditis and inflammatory cardiomyopathy has been observed in recent years. However, there is a growing potential of available non-invasive diagnostic methods (biomarkers, serum anti-heart autoantibodies (AHA), microRNAs, speckle tracking echocardiography, cardiac magnetic resonance T1 and T2 tissue mapping, positron emission tomography), which may refine the diagnostic workup and/or noninvasive follow-up. Personalized management should include the use of endomyocardial biopsy and AHA, which may allow the etiopathogenetic subsets of myocarditis (infectious, non-infectious, and/or immune-mediated) to be distinguished and implementation of disease-specific therapies. In this review, we summarize current knowledge on myocarditis and inflammatory cardiomyopathy, and outline some practical diagnostic, therapeutic, and follow-up algorithms to facilitate comprehensive individualized management of these patients.

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

Many systemic immune-mediated diseases (SIDs) may involve the heart and present as myocarditis with different histopathological pictures, i.e. lymphocytic, eosinophilic, granulomatous, and clinical features, ranging from a completely asymptomatic patient to life-threatening cardiogenic shock or arrhythmias. Myocarditis can be part of some SIDs, such as sarcoidosis, systemic lupus erythematosus, systemic sclerosis, antiphospholipid syndrome, dermato-polymyositis, eosinophilic granulomatosis with polyangiitis and other vasculitis syndromes, but also of some organ-based immune-mediated diseases with systemic expression, such as chronic inflammatory bowel diseases. The aim of this review is to describe the prevalence, main clinical characteristics and prognosis of myocarditis associated with SIDs.

Serum Organ-Specific Anti-Heart and Anti-Intercalated Disk Autoantibodies as New Autoimmune Markers of Cardiac Involvement in Systemic Sclerosis: Frequency, Clinical and Prognostic Correlates

BACKGROUND

Heart involvement (HInv) in systemic sclerosis (SSc) may relate to myocarditis and is associated with poor prognosis. Serum anti-heart (AHA) and anti-intercalated disk autoantibodies (AIDA) are organ and disease-specific markers of isolated autoimmune myocarditis. We assessed frequencies, clinical correlates, and prognostic impacts of AHA and AIDA in SSc.

METHODS

The study included consecutive SSc patients (n = 116, aged 53 ± 13 years, 83.6% females, median disease duration 7 years) with clinically suspected heart involvement (symptoms, abnormal ECG, abnormal troponin I or natriuretic peptides, and abnormal echocardiography). All SSc patients underwent CMR. Serum AHA and AIDA were measured by indirect immunofluorescence in SSc and in control groups of non-inflammatory cardiac disease (NICD) (n = 160), ischemic heart failure (IHF) (n = 141), and normal blood donors (NBD) (n = 270). AHA and AIDA status in SSc was correlated with baseline clinical, diagnostic features, and outcome.

RESULTS

The frequency of AHA was higher in SSc (57/116, 49%, p < 0.00001) than in NICD (2/160, 1%), IHF (2/141, 1%), or NBD (7/270, 2.5%). The frequency of AIDA was higher (65/116, 56%, p < 0.00001) in SSc than in NICD (6/160, 3.75%), IHF (3/141, 2%), or NBD (1/270, 0.37%). AHAs were associated with interstitial lung disease (p = 0.04), history of chest pain (p = 0.026), abnormal troponin (p = 0.006), AIDA (p = 0.000), and current immunosuppression (p = 0.01). AHAs were associated with death (p = 0.02) and overall cardiac events during follow-up (p = 0.017).

CONCLUSIONS

The high frequencies of AHA and AIDA suggest a high burden of underdiagnosed autoimmune HInv in SSc. In keeping with the negative prognostic impact of HInv in SSc, AHAs were associated with dismal prognosis.

CHANGES OF SERUM CARDIAC TROPONIN I IN EXERCISE STRESS TEST AND AFTER EXERCISE

ABSTRACT Introduction: Cardiac Troponin (CTN) has a strong organ specificity, which indicates that myocardial injury is present. However, it is worth noting that the increase does not suggest that the myocardium necessarily presents ischemic necrosis. Objective: To observe the changes in serum kerocalin I (CTNI) content after exercise, explore the effects of exercise training on hematocytes and that cause damage to myocardial cell stimulation. Methods: 18 rats were divided into three groups in this study, and three exercises were conducted separately. Results: After 6 weeks of exercise training, the number of red blood cells increased and the content of troponin I (CTNI) in the serum also significantly increased. The serum CTNI of the disposable large strength group was significantly higher than that of the quiet group (P <0.001). The serum CTNI in the 6-week exercise group was significantly higher than that of the quiet group (P <0.001), but the serum CTNI level between the two sports groups was not different. Conclusions: The motion training model used in this study can improve the number of red blood cells in the blood, improve synchronous blood capacity, and help the body's aerobic capacity increase. Level of evidence II; Therapeutic studies - investigation of treatment results.