Autoimmunity and heart diseases: pathogenesis and diagnostic criteria

Evaluation of Cardiac Arrhythmia Susceptibility in Pediatric Familial Mediterranean Fever Patients

Aim: Familial Mediterranean fever is an autoinflammatory disease characterized by attacks of inflammation. Despite treatment, there is evidence of subclinical persistence of inflammation with normal laboratory values. This study was conducted to investigate the cardiac effects of continued subclinical inflammation in children and the predisposition towards arrhythmia in familial Mediterranean fever. Materials and Methods: Age and sex-matched familial Mediterranean fever patients and healthy controls were compared in terms of demographic, laboratory, echocardiographic and electrocardiographic data. The patients with familial Mediterranean fever were grouped according to disease severity scores and compared in terms of electrocardiographic data that could indicate arrhythmogenesis. Correlation analysis was used to examine the relationship between the electrocardiographic measurements and the clinical and laboratory data. Results: In the comparison of the two groups, no significant difference was found in the echocardiographic measurements in terms of left ventricular systolic and diastolic functions. According to these data, QT and Tp-e intervals were significantly longer in those with familial Mediterranean fever (p=0.002, p=0.046, respectively). When the patients were classified according to the 3 separate disease severity scores, QT dispersion in the moderate-severe disease group was significantly longer than in the mild disease group (p

Autoantibodies in Atrial Fibrillation-State of the Art

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. To date, a lot of research has been conducted to investigate the underlying mechanisms of this disease at both molecular and cellular levels. There is increasing evidence suggesting that autoimmunity is an important factor in the initiation and perpetuation of AF. Autoantibodies are thought to play a pivotal role in the regulation of heart rhythm and the conduction system and, therefore, are associated with AF development. In this review, we have summarized current knowledge concerning the role of autoantibodies in AF development as well as their prognostic and predictive value in this disease. The establishment of the autoantibody profile of separate AF patient groups may appear to be crucial in terms of developing novel treatment approaches for those patients; however, the exact role of various autoantibodies in AF is still a matter of ongoing debate.

The Contribution of Autoantibodies to Inflammatory Cardiovascular Pathology

Chronic inflammation and resulting tissue damage underlie the vast majority of acquired cardiovascular disease (CVD), a general term encompassing a widely diverse array of conditions. Both innate and adaptive immune mechanisms contribute to chronic inflammation in CVD. Although maladies, such as atherosclerosis and cardiac fibrosis, are commonly conceptualized as disorders of inflammation, the cellular and molecular mechanisms that promote inflammation during the natural history of these diseases in human patients are not fully defined. Autoantibodies (AAbs) with specificity to self-derived epitopes accompany many forms of CVD in humans. Both adaptive/induced iAAbs (generated following cognate antigen encounter) and also autoantigen-reactive natural antibodies (produced independently of infection and in the absence of T cell help) have been demonstrated to modulate the natural history of multiple forms of CVD including atherosclerosis (atherosclerotic cardiovascular disease), dilated cardiomyopathy, and valvular heart disease. Despite the breadth of experimental evidence for the role of AAbs in CVD, there is a lack of consensus regarding their specific functions, primarily due to disparate conclusions reached, even when similar approaches and experimental models are used. In this review, we seek to summarize the current understanding of AAb function in CVD through critical assessment of the clinical and experimental evidence in this field. We additionally highlight the difficulty in translating observations made in animal models to human physiology and disease and provide a summary of unresolved questions that are critical to address in future studies.

Late ventricular potentials in familial Mediterranean fever with and without AA amyloidosis

Objective

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by episodic and chronic inflammation that may lead to both accelerated coronary atherosclerosis and cardiac AA amyloidosis. We hypothesized that late ventricular potentials (LPs), an established electrocardiographic susceptibility marker of ventricular arrhythmias, will be more common in FMF than in the adjusted normal population due to these two types of inflammation-associated cardiac effects. Therefore, we aimed to evaluate the occurrence of LPs in FMF patients with and without amyloidosis.

Material and Methods

Signal-averaged electrocardiography was performed in consecutive patients with FMF using the Frank corrected orthogonal lead system. At least 200 consecutive beats were digitally recorded and averaged, and the presence of LPs was determined according to acceptable thresholds.

Results

There were 54 patients with colchicine-treated FMF, of whom 14 had biopsy-proven AA amyloidosis. None of the uncomplicated FMF patients and 2 of the 14 FMF amyloidosis patients had abnormal or borderline LPs.

Conclusion

Based on LPs as a susceptibility marker for arrhythmia, FMF patients, including the large majority of FMF patients with amyloidosis, are seemingly not at an increased risk to develop arrhythmias.

Cardiomyopathy - An approach to the autoimmune background

Autoimmunity is increasingly accepted as the origin or amplifier of various diseases. In contrast to classic autoantibodies (AABs), which induce immune responses resulting in the destruction of the affected tissue, an additional class of AABs is directed against G-protein-coupled receptors (GPCRs; GPCR-AABs). GPCR-AABs functionally affect their related GPCRs for activation of receptor mediated signal cascades. Diseases which are characterized by the presence of GPCR-AABs with evidence for disease-specific pathogenic activity could be named "functional autoantibody disease". We briefly summarize here the historical view on autoimmunity in cardiomyopathy, followed by an approach to the mechanistic autoimmunity background. Furthermore, autoantibodies with outstanding importance for cardiomyopathies as a functional autoantibody disease, such as GPCR-AABs, and mainly those directed against the beta1-adrenergic and muscarinic 2 receptor autoantibodies, are introduced. Anti-cardiac myosin and anti-cardiac troponin autoantibodies, as further potential players in autoimmune cardiomyopathy, are additionally taken into account. The basic view on the autoantibodies, their related receptor interactions and pathogenic consequences are presented. Focused specifically on GPCR-AABs, "pros and cons" of assays such as indirect assays (functional changes of cell preparations are monitored after GPCR-AAB receptor binding) and direct assays based on the ELISA technologies (GPCR epitope mimics for GPCR-AAB binding) are critically discussed. Last but not least, treatment strategies for "functional autoantibody disease", such as for GPCR-AAB removal (therapeutic plasma exchange, immunoadsorption) and in vivo GPCR-AAB attack such as intravenous IgG treatment (IVIG), B-cell depletion and GPCR-AAB binding and neutralization, are critically reflected with respect to their patient benefits.

Stabbing Yourself in the Heart: A Case of Autoimmunity Gone Awry

Within internal medicine, cardiac and neurologic pathology comprises a vast majority of patient complaints. Physicians and advanced-care practitioners must be highly educated and comfortable in the evaluation, diagnosis, and management of these entities. Chest pain accounts for millions of annual visits to the emergency room with pericarditis diagnosed in approximately four percent of patients with nonischemic chest pain. Guillain-Barre Syndrome is autoimmune polyneuropathy that often results in transient paralysis. Simultaneous diagnosis of both entities is a rare but described phenomenon. Here, we present a clinical case of GBS associated pericarditis. A fifty-five-year-old man with history of renal transplant presented with lower extremity weakness and urinary incontinence. Physical exam and diagnostic studies confirmed Guillain-Barre Syndrome. Patient subsequently developed stabbing chest pain with clinical presentation and electrocardiogram consistent with pericarditis. The patient was successfully treated for both diseases. This case highlights that although infrequent, internal medicine care providers must be cognizant of this correlation to ensure timely diagnosis and treatment.

Identification of 4-Trimethylaminobutyraldehyde Dehydrogenase (TMABA-DH) as a Candidate Serum Autoantibody Target for Kawasaki Disease

Kawasaki disease (KD), an acute vasculitis that preferentially affects coronary arteries, is still the leading cause of acquired heart disease in children. Although the involvement of immune system malfunction in the onset of KD is suggested, its etiology still remains to be clarified. We investigated autoantibodies in KD patients, which are frequently found in sera from patients with autoimmune diseases, vasculitides and arteritides. We performed two-dimensional western blotting and LC-MS/MS to analyze the antigens of autoantibodies, detected two protein spots with 4 out of 24 sera from KD patients but not with 6 control sera, and identified the antigens as 4-trimethylaminobutyraldehyde dehydrogenase (TMABA-DH). A slot blot analysis with TMABA-DH as an antigen also revealed higher reactivities of patients' sera than control sera (positive rates: 18/43 vs 3/41). Using an enzyme-linked immunosorbent assay (ELISA), we found that the reactivity of anti-TMABA-DH antibodies in sera from KD patients was significantly higher than that in sera from age-matched controls. The optimal cut-off value of 0.043 had a sensitivity of 83.7% and a specificity of 80.0% in detecting KD patients (positive rates: 37/43 for KD patients, 9/41 for controls). Immunohistochemistry performed on thin sections of rat heart revealed that TMABA-DH colocalized with myosin light chains in cardiac myocytes. Patient sera with high reactivity gave similar immunostaining pattern. These results suggest that the detection of anti-TMABA-DH autoantibody could be a potential strategy for a diagnosis of KD.

Sex differences in inflammation during atherosclerosis

Atherosclerosis is the leading cause of death in the United States and worldwide, yet more men die from atherosclerosis than women, and at a younger age. Women, on the other hand, mainly develop atherosclerosis following menopause, and particularly if they have one or more autoimmune diseases, suggesting that the immune mechanisms that increase disease in men are different from those in women. The key processes in the pathogenesis of atherosclerosis are vascular inflammation, lipid accumulation, intimal thickening and fibrosis, remodeling, and plaque rupture or erosion leading to myocardial infarction and ischemia. Evidence indicates that sex hormones alter the immune response during atherosclerosis, resulting in different disease phenotypes according to sex. Women, for example, respond to infection and damage with increased antibody and autoantibody responses, while men have elevated innate immune activation. This review describes current knowledge regarding sex differences in the inflammatory immune response during atherosclerosis. Understanding sex differences is critical for improving individualized medicine.

Autoimmunity and autoinflammation as the yin and yang of idiopathic recurrent acute pericarditis

Autoimmunity and autoinflammation are generally considered as mutually exclusive mechanisms of diseases but may concur to specific syndromes. Idiopathic recurrent acute pericarditis (IRAP) is defined as the recurrence of pericardial symptoms at any point following the prior cessation of acute pericarditis, and the latency is generally 6 weeks. Manifestations of pericarditis such as pericardial friction rub, electrocardiographic changes, and pericardial effusion are less frequent in the subsequent episodes compared to the index attack, and in some cases the only clinical sign is represented by a suggestive chest pain. Several autoimmune diseases may manifest with pericarditis which is often related to viral infections, while postviral pericarditis may in turn display a nonspecific autoimmune background. Similarly, autoinflammatory syndromes such as familial Mediterranean fever and tumor necrosis factor receptor-associated periodic syndrome are characterized by self-limiting pericardial symptoms. Corticosteroids are generally effective, thus supporting the autoimmune nature of IRAP, but dramatic results are obtained with interleukin-1 blocking agents in corticosteroid-dependent cases, pointing to a pathogenic role for the inflammasome. Based on these observations, we submit that IRAP represents a paradigmatic example of the putative coexistence of autoimmunity and autoinflammation: the main aim of this review is to critically discuss the hypothesis as well as the current understanding of this enigmatic clinical condition.

Cardiovascular involvement in autoimmune diseases

Autoimmune diseases (AD) represent a broad spectrum of chronic conditions that may afflict specific target organs or multiple systems with a significant burden on quality of life. These conditions have common mechanisms including genetic and epigenetics factors, gender disparity, environmental triggers, pathophysiological abnormalities, and certain subphenotypes. Atherosclerosis (AT) was once considered to be a degenerative disease that was an inevitable consequence of aging. However, research in the last three decades has shown that AT is not degenerative or inevitable. It is an autoimmune-inflammatory disease associated with infectious and inflammatory factors characterized by lipoprotein metabolism alteration that leads to immune system activation with the consequent proliferation of smooth muscle cells, narrowing arteries, and atheroma formation. Both humoral and cellular immune mechanisms have been proposed to participate in the onset and progression of AT. Several risk factors, known as classic risk factors, have been described. Interestingly, the excessive cardiovascular events observed in patients with ADs are not fully explained by these factors. Several novel risk factors contribute to the development of premature vascular damage. In this review, we discuss our current understanding of how traditional and nontraditional risk factors contribute to pathogenesis of CVD in AD.

The correlation between peripartum cardiomyopathy and autoantibodies against cardiovascular receptors

Background

Peripartum cardiomyopathy (PPCM) is characterized by left ventricular systolic dysfunction and heart failure. However, its pathogenesis is not clear. Our preliminary study revealed that autoantibodies against β₁-adrenergic receptors (β₁R-AABs) and M₂-muscarinic receptors (M₂R-AABs) participated in heart failure regardless of primary heart disease. Whether β₁R-AABs and M₂R-AABs participate in the pathogenesis of PPCM is still unknown.

Methods

Totally 37 diagnosed PPCM patients and 36 normal pregnant women were enrolled in this study. Clinical assessment and 2-dimensional echocardiographic studies as well as the measurement of β₁R-AABs or M₂R-AABs by enzyme linked immunosorbent assay (ELISA) were performed.

Results

The positive rates for β₁R-AABs and M₂R-AABs were 59.5% (22/37) and 45.9% (17/37) in PPCM patients, and 19.4% (7/36) (P<0.001) and 16.67% (6/36) (P<0.001) in normal pregnant women, respectively. Both β₁R-AABs and M₂R-AABs had a positive correlation with serum expression level of NT-proBNP, left ventricular dimension and NYHA FC (rs: 0.496–0.892, P<0.01). In addition, a negative correlation between the activity of β₁R-AABs and M₂R-AABs and LVEF, LVFS was observed (rs: −0.488–0.568, P<0.01). Moreover, autoantibodies against cardiovascular receptors increased the risk of the onset of PPCM (OR = 18.786, 95% confidence interval 1.926–183.262, P = 0.012).

Conclusions

The β₁R-AABs and M₂R-AABs reveal a significant elevation and are correlated with the increased left ventricular dimension and worse cardiac contraction function. The autoantibodies of cardiovascular receptors are independent risk factors for the onset of PPCM.

Edema and fibrosis imaging by cardiovascular magnetic resonance: how can the experience of Cardiology be best utilized in rheumatological practice?

OBJECTIVES

CMR, a non-invasive, non-radiating technique can detect myocardial oedema and fibrosis.

METHOD

CMR imaging, using T2-weighted and T1-weighted gadolinium enhanced images, has been successfully used in Cardiology to detect myocarditis, myocardial infarction and various cardiomyopathies.

RESULTS

Transmitting this experience from Cardiology into Rheumatology may be of important value because: (a) heart involvement with atypical clinical presentation is common in autoimmune connective tissue diseases (CTDs). (b) CMR can reliably and reproducibly detect early myocardial tissue changes. (c) CMR can identify disease acuity and detect various patterns of heart involvement in CTDs, including myocarditis, myocardial infarction and diffuse vasculitis. (d) CMR can assess heart lesion severity and aid therapeutic decisions in CTDs.

CONCLUSION

The CMR experience, transferred from Cardiology into Rheumatology, may facilitate early and accurate diagnosis of heart involvement in these diseases and potentially targeted heart treatment.

Role of autoimmunity and autoinflammation in the pathogenesis of idiopathic recurrent pericarditis

Idiopathic recurrent pericarditis is the most common and troublesome complication of acute pericarditis affecting about one third of such patients. The pericardium may be involved in different systemic autoimmune diseases (i.e., systemic lupus erythematosus, rheumatoid arthritis, progressive systemic sclerosis, mixed connective tissue disease, Sjogren's Syndrome, polyarteritis, giant cell arteritis, other systemic vasculitides) either in a symptomatic form (usually during the active phase of the disease) or as asymptomatic pericardial effusion. Moreover, idiopathic recurrent pericarditis mimicks hereditary periodic fever syndromes (HPFSs). HPFSs are a group of disorders characterized by primary dysfunction of the innate immune system mostly caused by mutations of genes involved in the regulation or activation of the inflammatory response, without any apparent involvement of antigen-specific T cells or significant production of autoantibodies. These disorders usually manifest in the pediatric population, with onset ranging from the first hours to the first decade of life, however a limited number of patients experience disease onset during adulthood.

The diagnostic and clinical significance of anti-muscarinic receptor autoantibodies

The role of autoimmunity in cardiovascular diseases has become one of the focal points of research studies. Autoimmune response and autoreactive autoantibodies have been found in dilated cardiomyopathy, heart failure, rheumatic fever, myocarditis, atherosclerosis, and other diseases. Autoantibodies may appear due to tissue injury and exposure of autoantigens, in addition to molecular mimicry and cross-reactivity with antigens found in infectious agents in predisposed individuals. In the early 1990s, autoantibodies reacting with the M2 muscarinic receptor were found in patients with dilated cardiomyopathy and subsequently, in patients with Chagas heart disease and arrhythmic disorders. Immunization of animals with the corresponding antigen triggered cardiac abnormalities also appearing in dilated cardiomyopathy of humans. It has been suggested that antibodies against M2 muscarinic receptors play a role in the pathogenesis of cardiac diseases and may also alter the electrophysiological properties of cardiac tissue. Herein, we review the current knowledge of antibodies against M2 muscarinic receptors and the possible use of a targeted therapy against these autoantibodies.

Republished: pathogenesis and diagnosis of myocarditis

Acute myocarditis is an inflammatory disease of the heart muscle that may progress to dilated cardiomyopathy and chronic heart failure. A number of factors including the sex hormone testosterone, components of innate immunity, and profibrotic cytokines have been identified in animal models as important pathogenic mechanisms that increase inflammation and susceptibility to chronic dilated cardiomyopathy. The clinical presentation of acute myocarditis is non-specific and mimics more common causes of heart failure and arrhythmias. Suspected myocarditis is currently confirmed using advanced non-invasive imaging and histopathologic examination of heart tissue. However, the diverse presentations of myocarditis and the lack of widely available, safe, and accurate non-invasive diagnostic tests remain major obstacles to early diagnosis and population based research. Recent advances in the understanding of disease pathogenesis described in this review should lead to more accurate diagnostic algorithms and non-invasive tests.

Autoimmune heart disease: role of sex hormones and autoantibodies in disease pathogenesis

Cardiovascular disease (CVD) and autoimmune diseases (ADs) are the first and third highest causes of death in the USA, respectively. Men have an increased incidence of the majority of CVDs, including atherosclerosis, myocarditis, dilated cardiomyopathy and heart failure. By contrast, nearly 80% of all ADs occur in women. However, in one category of ADs, rheumatic diseases, CVD is the main cause of death. Factors that link rheumatic ADs to CVD are inflammation and the presence of autoantibodies. In this review we will examine recent findings regarding sex differences in the immunopathogenesis of CVD and ADs, explore possible reasons for the increased occurrence of CVD within rheumatic ADs and discuss whether autoantibodies, including rheumatoid factor, could be involved in disease pathogenesis.

Differences in virus prevalence and load in the hearts of patients with idiopathic dilated cardiomyopathy with and without immune-mediated inflammatory diseases

Infections with cardiotrophic viruses and immune-mediated responses against the heart have been suggested to play a dominant role in the pathogenesis of idiopathic dilated cardiomyopathy (DCM). Furthermore, immune-mediated inflammatory diseases (IMIDs) may result in DCM. It has not previously been assessed whether DCM patients with and without an IMID have different prevalences and quantities of cardiotrophic viruses in the heart. Therefore, we compared the profiles of cardiotrophic viruses in heart tissue of DCM patients with and without an IMID. Serum and myocardial tissue samples were obtained from 159 consecutive patients with DCM and 20 controls. Patients were subdivided into three groups, the first two based on the presence (n = 34) or absence (n = 125) of an IMID and the third being a control group. The parvovirus B19 virus genome was detected in equal quantities in the non-IMID DCM patients (100/125) and the control group (15/20) but in lower quantities in the IMID patients (21/34, P = 0.02). Both the non-IMID and IMID DCM patients demonstrated increased myocardial inflammation compared to controls: 12.5 ± 1.8 and 14.0 ± 3.2 CD45-positive inflammatory cells, respectively, versus 5.1 ± 0.7 for the controls (P < 0.05 for both). Importantly, significantly higher parvovirus B19 copy numbers could be amplified in non-IMID than in IMID patients (561 ± 97 versus 191 ± 92 copies/μg DNA, P < 0.001) and control subjects (103 ± 47 copies/μg DNA, P < 0.001). The present study shows decreased parvovirus B19 prevalence and copy numbers in hearts of DCM patients with an IMID compared to those without an IMID. These findings may suggest that DCM patients with an IMID have a different pathophysiologic mechanism from that which is present in the virus-induced form of DCM.

The role of gender and organ specific autoimmunity

Autoimmunity is influenced by multiple factors including gender and sex hormones. A definite female predominance is found in many autoimmune diseases. Gender is also associated with differences in clinical presentation, onset, progression and outcome of autoimmune diseases. Sex hormones might influence the target organ's vulnerability to an autoimmune response. Gender differences also exist in organ specific autoimmune diseases such as multiple sclerosis, Guillain-Barré syndrome, Crohn's disease and celiac disease. Nevertheless, other organ specific autoimmune diseases (i.e. ulcerative colitis) are seemingly characterized with similar prevalence in both males and females. The reason for gender differences in certain autoimmune diseases remains unknown, but may be attributed to sex hormone influence, fetal microchimerism, X chromosome inactivation, and X chromosome abnormalities. Sex hormones have been found to have immune modulating properties, as well as providing cellular protection following tissue damage in certain circumstances. Sex hormones also influence innate and adaptive immune cells, number of B and T cells, antigen presentation and cytokine secretion. Herein, we review the influence of gender on organ-specific autoimmune diseases affecting the heart, blood vessels, central nervous system and gastrointestinal tract. It appears that sex hormones may have a therapeutic potential in several autoimmune conditions, although further research is required before therapeutic recommendations can be made.

Autoantibodies and cardiac arrhythmias

Autoimmune diseases are associated with significant morbidity and mortality, afflicting about 5% of the US population. They encompass a wide range of disorders that affect all organs of the human body and have a predilection for women. In the past, autoimmune pathogenesis was not thought to be a major mechanism for cardiovascular disorders, and potential relationships remain understudied. However, accumulating evidence suggests that a number of vascular and cardiac conditions are autoimmune mediated. Recent studies indicate that autoantibodies play an important role in the development of cardiac arrhythmias, including atrial fibrillation, modulation of autonomic influences on heart rate and rhythm, conduction system abnormalities, and ventricular arrhythmias. This article will review the current evidence for the role of autoantibodies in the development of cardiac arrhythmias.

Antibodies reactive to non-HLA antigens in transplant glomerulopathy

Although T and B cell alloimmunity contribute to transplant injury, autoimmunity directed at kidney-expressed, non-HLA antigens may also participate. Because the specificity, prevalence, and importance of antibodies to non-HLA antigens in late allograft injury are poorly characterized, we used a protein microarray to compare antibody repertoires in pre- and post-transplant sera from several cohorts of patients with and without transplant glomerulopathy. Transplantation routinely induced changes in antibody repertoires, but we did not identify any de novo non-HLA antibodies common to patients with transplant glomerulopathy. The screening studies identified three reactivities present before transplantation that persisted after transplant and strongly associated with transplant glomerulopathy. ELISA confirmed that reactivity against peroxisomal-trans-2-enoyl-coA-reductase strongly associated with the development of transplant glomerulopathy in independent validation sets. In addition to providing insight into effects of transplantation on non-HLA antibody repertoires, these results suggest that pretransplant serum antibodies to peroxisomal-trans-2-enoyl-coA-reductase may predict prognosis in kidney transplantation.

Atherosclerosis and macrovascular involvement in systemic sclerosis: myth or reality

Systemic sclerosis (SSc) is a chronic disease of unknown etiology, characterized by enhanced fibrosis, and microvascular abnormalities. During the past several decades, the death rates due to cardiovascular disease or cerebrovascular disease in SSc patients substantially increased and are currently responsible for 20-30% of mortality. Various autoimmune rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus accelerate atherosclerosis. Although microvascular disease is a hallmark of SSc, an ongoing debate exists regarding the presence and extent of macrovascular diseases and the presence of accelerated atherosclerosis in SSc patients. Despite conflicting results as to intima-media thickness (IMT) in SSc patients, the most recent and largest study has found no difference in either plaque occurrence or IMT. Additionally, abnormal coronary flow reserve in SSc patients appears to be due to microvascular involvement rather than atherosclerosis of the epicardial coronary arteries. Angiographic findings as well as computed tomography studies have generated conflicting reports as to coronary atherosclerosis in SSc. Herein, we review the current knowledge of macrovascular involvement and atherosclerosis in SSc. The differences between SSc and other autoimmune rheumatic diseases in the presence and extent of atherosclerosis need to be further investigated.

Innate versus acquired immune response in the pathogenesis of recurrent idiopathic pericarditis

The pathogenesis of recurrent pericarditis is still poorly understood and may be related either to viral infections or autoimmune and autoinflammatory disorders. The immune system plays a major role in the pathogenesis of the disease, modulating individual responses to different noxa and explaining the variable reported recurrence rate (ranging from 20% to 50% of patients) following an attack of acute or recurrent pericarditis. Increasing interest is currently being devoted to autoinflammatory disorders, a group of conditions characterized by spontaneously relapsing and remitting bouts of systemic inflammation without apparent involvement of antigen-specific T cells or significant production of auto-antibodies. Ongoing basic and clinical research is needed to provide further evidence for the understanding of this common and troublesome disease, and to develop targeted and more efficacious therapies.

Heart rate variability in familial Mediterranean fever

Familial Mediterranean fever (FMF) is a hereditary disease, characterized by recurrent episodes of fever and polyserositis. Heart rate variability (HRV) is a powerful, simple and reliable technique to evaluate autonomic nervous system function. Previous studies of physiologic parameters during tilt-test have suggested that patients with FMF have abnormal cardiovascular reactivity and occult dysautonomia. Prompted by these findings, the present study sought to evaluate HRV in patients with FMF, at rest and in the standing position. The study sample included 34 patients with FMF and 34 sex- and age-matched control subjects. All underwent electrocardiography according to strict criteria. HRV parameters were computed with custom-made software. There was no significant difference in HRV parameters, in either the supine or standing position, between the FMF and control groups. In both groups, the upright position was associated with a significant decrease, when compared with the supine position, in maximal RR interval, minimal RR, average RR, root square of successive differences in RR interval, number of intervals differing by >50 ms from preceding interval (NN50), NN50 divided by total number of intervals (pNN50) and high-frequency components as well as a significant increase in average heart rate, very low frequency or low-frequency components, low-frequency/high-frequency components ratio and total power. In conclusion, patients with FMF who are continuously treated with low-dose colchicine have not developed amyloidosis and have normal HRV parameters in the supine and upright position. Further investigation of occult dysautonomia in FMF is needed.