Diagnosis, management, and outcome of cardiac sarcoidosis and giant cell myocarditis: a Swedish single center experience.

BACKGROUND: Cardiac sarcoidosis (CS) and giant cell myocarditis (GCM) are rare diseases that share some similarities, but also display different clinical and histopathological features. We aimed to compare the demographics, clinical presentation, and outcome of patients diagnosed with CS or GCM. METHOD: We compared the clinical data and outcome of all adult patients with CS (n = 71) or GCM (n = 21) diagnosed at our center between 1991 and 2020. RESULTS: The median (interquartile range) follow-up time for patients with CS and GCM was 33.5 [6.5-60.9] and 2.98 [0.6-40.9] months, respectively. In the entire cohort, heart failure (HF) was the most common presenting manifestation (31%), followed by ventricular arrhythmias (25%). At presentation, a left ventricular ejection fraction of < 50% was found in 54% of the CS compared to 86% of the GCM patients (P = 0.014), while corresponding proportions for right ventricular dysfunction were 24% and 52% (P = 0.026), respectively. Advanced HF (NYHA ≥ IIIB) was less common in CS (31%) than in GCM (76%). CS patients displayed significantly lower circulating levels of natriuretic peptides (P < 0.001) and troponins (P = 0.014). Eighteen percent of patients with CS included in the survival analysis reached the composite endpoint of death or heart transplantation (HTx) compared to 68% of patients with GCM (P < 0.001). CONCLUSION: GCM has a more fulminant clinical course than CS with severe biventricular failure, higher levels of circulating biomarkers and an increased need for HTx. The histopathologic diagnosis remained key determinant even after adjustment for markers of cardiac dysfunction.

Infections with the tick-borne bacterium "Candidatus Neoehrlichia mikurensis" mimic noninfectious conditions in patients with B cell malignancies or autoimmune diseases.

BACKGROUND: Candidatus Neoehrlichia mikurensis is a newly discovered noncultivatable bacterium spread among ticks and rodents in Europe and Asia that can infect humans, particularly immunocompromised patients. METHODS: We compiled clinical and laboratory data from 11 patients with hematological malignances or autoimmune diseases who were diagnosed with Candidatus N. mikurensis infection in Europe 2010-2013. Both published (6) and unpublished cases (5) were included. RESULTS: The patients had a median age of 67, were mostly male (8/11), and resided in Sweden, Switzerland, Germany, and the Czech Republic. All but one had ongoing or recent immune suppressive treatment and a majority were splenectomized (8/11). Less than half of them recalled tick exposure. The most frequent symptoms were fever (11/11), localized pain afflicting muscles and/or joints (8/11), vascular and thromboembolic events (6/11), that is, deep vein thrombosis (4), transitory ischemic attacks (2), pulmonary embolism (1), and arterial aneurysm (1). Typical laboratory findings were elevated C-reactive protein, leukocytosis with neutrophilia, and anemia. Median time from onset of symptoms to correct diagnosis was 2 months. In at least 4 cases, the condition was interpreted to be due to the underlying disease, and immunosuppressive therapy was scheduled. All patients recovered completely when doxycycline was administered. CONCLUSIONS: Candidatus N. mikurensis is an emerging tick-borne pathogen that may give rise to a systemic inflammatory syndrome in persons with hematologic or autoimmune diseases that could be mistaken for recurrence of the underlying disease and/or unrelated arteriosclerotic vascular events. Awareness of this new pathogen is warranted among rheumatologists, hematologists, oncologists, and infectious disease specialists.

Complement Consumption in Systemic Lupus Erythematosus Leads to Decreased Opsonophagocytosis In Vitro.

OBJECTIVE: Infections remain a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). The high prevalence of infections in SLE is attributed to both the disease and its treatments. The complement system plays an important role in host immune responses against invading microorganisms. We sought to provide the experimental and clinical evidence supporting the hypothesis that low levels of complement factors cause defective complement-mediated opsonization in patients with SLE. METHODS: Staphylococcus aureus was opsonized with sera from healthy individuals (n = 16), SLE patients with normal (n = 5) or low complement (n = 8) levels. Phagocytosis of S. aureus by healthy human neutrophils was analyzed by an imaging flow cytometry-based method. We retrospectively examined the infection incidence in relation to complement levels in a cohort of 165 patients with SLE during a 1.5-year period. The association was analyzed for infection incidence and disease-related variables. RESULTS: Uptake of S. aureus by neutrophils was decreased when S. aureus was opsonized with sera from SLE patients with low complement levels compared to sera from healthy individuals and SLE patients with normal complement. In our SLE cohort, 44% of patients had at least 1 infection during the 1.5 years. No significant association was observed between complement levels and infection risk. Importantly, high-dose glucocorticoids (GC; prednisone ≥ 10 mg/day) were the most important predictive factor for infections in patients with SLE. CONCLUSION: Low complement levels affect bacterial opsonization in SLE blood and lead to downregulated phagocytosis by neutrophils. High-dose GC increase the infection risk in patients with SLE.

Current status of pathogenetic mechanisms in staphylococcal arthritis.

Interactions between staphylococci and the joint tissues of the host lead typically to rapidly progressing and highly destructive processes. Staphylococci possess a vast arsenal of components and products that contribute to the pathogenesis of joint infection. Occasionally these compounds have overlapping activities and act either in concert or alone. Host responsiveness to staphylococcal infection displays an even more complex pattern. Most of the cells and molecules that participate in the innate immune system protect the host against bacteria. However, the staphylococci have developed systems that counteract endogenous protective mechanisms. Interestingly, certain cells and molecules of the acquired immune system potentiate the severity of infection by triggering exaggerated responses to the staphylococcal danger signals. This review deals with the intricate host-bacterium interactions that occur during experimental septic arthritis, and outlines potential preventive and treatment modalities.

Low molecular weight heparin aggravates infectious arthritis triggered by Staphylococcus aureus.

PURPOSE: Staphylococcus aureus is responsible for the majority of wound infections in clean surgical procedures that involve implantation of foreign material, grafts or prosthetic devices. The aim of the study was to assess the effect of low molecular weight heparin on the development and progression of S. aureus arthritis. MATERIALS AND METHODS: The murine model of hematogenously acquired septic arthritis was used injecting intravenously toxic shock syndrome toxin-1 (TSST-1) producing S. aureus of LS-1 strain. Mice lacking prosthetic implants were treated with intraperitoneal injections of low molecular weight heparin, used routinely as anti-thrombotic prophylaxis following joint prosthetic surgery. Evaluation of arthritis was performed clinically and histopathologically. In addition, the effect of low molecular weight heparin on T cell dependent and independent inflammation was assessed. RESULTS: Seven days after inoculation with bacteria 18 out of 19 low molecular weight heparin treated mice displayed clinical symptoms of arthritis as compared to 9 out of 23 control animals (p < 0.05), and the severity of arthritis, expressed as arthritic index, was 2.6+/-0.5 versus 1.6+/-0.5 (p = 0.05). The histopathological examination confirmed the clinical findings showing that both inflammation and joint destruction were more substantial in heparin treated animals. CONCLUSION: Our findings indicate that the routine anti-coagulation treatment with heparin contributes to more severe course of joint infection.

Endothelin-1 across the lung circulation in patients with pulmonary arterial hypertension and influence of epoprostenol infusion.

BACKGROUND: The endothelin-1 (ET-1) system plays a pathophysiologic role in patients with pulmonary arterial hypertension (PAH). Results from previous studies assessing the transpulmonary gradient of ET-1 have been inconsistent. The influence of an intravenous epoprostenol infusion on the transpulmonary ET-1 gradient is unknown. METHODS: In a prospective investigation, serum concentrations of ET-1 were measured in 39 consecutive patients (31 women; mean age, 20-77 years) with pulmonary hypertension (33 with PAH) and compared with 20 controls. The effect of intravenous epoprostenol administration on the transpulmonary gradient of ET-1 was analyzed in 13 patients with pulmonary hypertension. Blood samples were taken simultaneously from the pulmonary artery and radial artery. RESULTS: The serum levels of ET-1 were significantly higher in the arterial (3.9 +/- 1.28 vs 2.53 +/- 0.24 pg/ml, p < 0.001) and mixed venous blood samples (3.9 +/- 1.21 vs 2.52 +/- 0.29 pg/ml, p < 0.001) in patients with pulmonary hypertension than in controls. The arterial/venous ratio of ET-1 in patients (1.0 +/- 0.1) and in the control group (1.0 +/- 0.05) was similar (p = 0.79). During intravenous epoprostenol infusion, there were no changes in the mean transpulmonary ET-1 gradient (0.98 +/- 0.07 vs 0.96 +/- 0.09, p = 0.52), despite significant hemodynamic changes. CONCLUSION: The ET-1 radial artery/pulmonary artery ratio of unity indicates a balanced release and clearance of ET-1 across the lung circulation in controls and in patients with different forms of pulmonary hypertension. ET-1 levels across the pulmonary circulation did not change during epoprostenol infusion.

Combined antibiotic and free radical trap treatment is effective at combating Staphylococcus-aureus-induced septic arthritis.

Although early antibiotic treatment of patients with septic arthritis eradicates bacteria, joint destruction commonly results from the unregulated host inflammatory responses to infection. The spin trap compound phenyl-N-tert-butyl nitrone (PBN) has been shown to have both anti-inflammatory and antioxidant effects. The aim of this study was to assess the effect of combined systemic administration of PBN and cloxacillin on the development of Staphylococcus aureus arthritis.Three days after Naval Medical Research Institute (NMRI) mice were infected intravenously with S. aureus LS-1, daily treatment was started with cloxacillin alone, PBN alone, or cloxacillin and PBN. Arthritis, weight loss and general condition were evaluated for each mouse, and joints were analyzed histopathologically. Systemic administration of PBN in conjunction with cloxacillin ameliorated the course of experimental S. aureus arthritis, as evidenced by an increased cure rate. Thus, combinatorial antioxidant plus antibiotic anti-inflammatory therapies represent a potentially efficacious approach to the management of septic arthritis.

Microbial superantigens as virulence factors and ways to counteract their actions.

Microbial superantigens represent a group of molecules that is able to cause massive activation of the host immune system. Human diseases originating from superantigen-secreting bacterial agents are characterized by shock, which continues to pose major health problems. Presently, the treatment of superantigen-mediated infections is limited to the administration of antibiotics and handling of the state of shock. However, the development of multiple antibiotic-resistant, superantigen-producing bacterial strains increases the threat of these infections, and prompts researchers to better understand and treat disease states in which exposure to superantigens is at least partly responsible for the outcome. In the past decade, significant understanding has been achieved regarding the molecular mechanisms of superantigen-host interactions. Based on this understanding, a variety of promising strategies directed against superantigens have been developed. In this review, we discuss some of these strategies, as well as the potential for therapeutic applications of superantigens for the benefit of the host.