Marked QTc Prolongation and Torsades de pointes in Patients with Chronic Inflammatory Arthritis

Mounting evidence indicates that in chronic inflammatory arthritis (CIA), QTc prolongation is frequent and correlates with systemic inflammatory activation. Notably, basic studies demonstrated that inflammatory cytokines induce profound changes in potassium and calcium channels resulting in a prolonging effect on cardiomyocyte action potential duration, thus on the QT interval on the electrocardiogram. Moreover, it has been demonstrated that in rheumatoid arthritis (RA) patients, the risk of sudden cardiac death is significantly increased when compared to non-RA subjects. Conversely, to date no data are available about torsades de pointes (TdP) prevalence in CIA, and the few cases reported considered CIA only an incidental concomitant disease, not contributing factor to TdP development. We report three patients with active CIA developing marked QTc prolongation, in two cases complicated with TdP degenerating to cardiac arrest. In these patients, a blood sample was obtained within 24 h from TdP/marked QTc prolongation occurrence, and levels of IL-6, TNFα, and IL-1 were evaluated. In all three cases, IL-6 was markedly elevated, ~10 to 100 times more than reference values. Moreover, one patient also showed high circulating levels of TNFα and IL-1. In conclusion, active CIA may represent a currently overlooked QT-prolonging risk factor, potentially contributing in the presence of other "classical" risk factors to TdP occurrence. In particular, a relevant role may be played by elevated circulating IL-6 levels via direct electrophysiological effects on the heart. This fact should be carefully kept in mind, particularly when recognizable risk factors are already present and/or the addition of QT-prolonging drugs is required

Diagnostic role of minor salivary glands biopsy in Sjögren’s syndrome: correlations between histology and autoimmunity in a large, monocentric cohort

Introduction Based on ACR/EULAR classification criteria, minor salivary glands biopsy (MSGB) is a useful diagnostic tool for the diagnosis of primary Sjögren’s syndrome (SS). The main objective of our study was to evaluate the diagnostic role of MSGB, as well as to highlight correlations between histological findings and autoimmune profiles. Material and methods We retrospectively evaluated histological and autoimmunity data from patients who underwent MSGB in our department in cases of suspected SS, from March 2011 to December 2018. Salivary gland samples were evaluated using Chisholm and Mason (CM) grading and the focus score (FS). Results A total of 1,264 patients (108 males, 1,156 females) were included. The median age was 55.22 ±13.51 years (range: 15–87). In univariate binary logistic regression, CM ≥ 3 and FS ≥ 1 were significantly predicted by antinuclear antibodies (ANA), anti-extractable nuclear antigens (ENA) and anti-Ro/SSA titer as well as anti-La/SSB, anti-Ro/SSA, rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA) positivity. In multivariate analysis, CM ≥ 3 and MSGB positivity were significantly associated with ANA titer; FS ≥ 1 was not associated with laboratory findings. A positive biopsy was associated with laboratory findings, as ANA and ENA titers, anti-Ro/SSA, anti-La/SSB, RF and ACPA positivity may discriminate patients with SS-related histological findings. Conclusions Minor salivary glands biopsy is a useful tool to diagnose SS in cases of highly suggestive clinical symptoms but in the absence of a specific autoimmunity

Arrhythmogenicity of Anti-Ro/SSA antibodies in patients with torsades de pointes

Background - In patients with autoimmune disease, anti-Ro/SSA antibodies (anti-Ro/SSA) are responsible for a novel autoimmune-associated long-QT syndrome by targeting the hERG potassium channel and inhibiting the related current (I Kr). Because anti-Ro/SSA are also present in a significant proportion of healthy subjects and may be associated with torsades de pointes (TdP) arrhythmia, we tested the hypothesis that anti-Ro/SSA may represent a silent risk factor in patients developing TdP. Methods and Results - Twenty-five consecutive patients who experienced TdP were prospectively collected independent of ongoing therapies and concomitant diseases. Anti-Ro/SSA were detected by fluoroenzyme immunoassay, immuno-Western blotting, and line-blot immunoassay. Purified IgGs from anti-Ro/SSA-positive and anti-Ro/SSA-negative patients were tested on I Kr using HEK293 cells stably expressing the hERG channel. As expected, in TdP patients, many known corrected QT interval-prolonging risk factors were simultaneously present, including hypokalemia that was the most common (52%). Anti-Ro/SSA were present in 60% of the subjects, mostly the anti-Ro/SSA-52-kD subtype detected by immuno-Western blotting only. A history of autoimmune disease was found in only 2 of anti-Ro/SSA-positive patients. Experimental data demonstrated that purified anti-Ro/SSA-positive IgGs significantly inhibited I Kr and cross reacted with hERG-channel proteins. Moreover, anti-Ro/SSA-positive sera exhibited high reactivity with a peptide corresponding to the hERG-channel pore-forming region. Conclusions - Anti-Ro/SSA may represent a clinically silent novel risk factor for TdP development via an autoimmune-mediated electrophysiological interference with the hERG channel. We propose that TdP patients may benefit from specific anti-Ro/SSA testing even in the absence of autoimmune diseases as immunomodulating therapies may be effective in shortening corrected QT interval and reducing TdP recurrence risk

Current technologies for anti-ENA antibody detection: State-of-the-art of diagnostic immunoassays

Background: Autoantibodies against extractable nuclear antigens (ENA) play a pivotal role in the diagnosis and classification of systemic autoimmune rheumatic diseases (SARD). In recent years, newly developed methods have enabled the simultaneous and quantitative detection of multiple anti-ENA reactivities. However, data regarding the comparability of results obtained using different technologies across different platforms are scarce. In this study we compared eight different immunoassays, commonly used in current laboratory practice for detection of anti-ENA antibodies. Methods: Sixty patients suffering from different SARD, 10 inflammatory arthritis patients (disease controls) and 10 healthy blood donors were included in this comparative study. Sera were collected in 15 centers belonging to the Study Group on Autoimmune Diseases of the Italian Society of Clinical Pathology and Laboratory Medicine. We evaluated the analytical sensitivity, specificity and diagnostic accuracy of each method for antibodies to Sm, RNP, Ro60, Ro52, Scl70, CENP-B and Jo1. Cohen's kappa was used to analyze the agreement among methods. Results: Average agreement among methods was 0.82, ranging from substantial (k = 0.72) to almost perfect (k = 0.92). However, while the specificity was very good for all methods, some differences emerged regarding the analytical sensitivity. Conclusions: Diagnostic performance of current technologies for anti-ENA antibody detection showed good comparability. However, as some differences exist among methods, laboratory scientists and clinicians must be aware of the diagnostic accuracy of the testing method in use

Systemic inflammation as a novel QT-prolonging risk factor in patients with torsades de pointes

Objective Increasing evidence indicates systemic inflammation as a new potential cause of acquired long QT syndrome (LQTS), via cytokine-mediated changes in cardiomyocyte ion channels. Torsade de pointes (TdP) is a life-threatening polymorphic ventricular tachycardia occurring in patients with LQTS, usually when multiple QT-prolonging factors are simultaneously present. Since classical risk factors cannot fully explain TdP events in a number of patients, we hypothesised that systemic inflammation may represent a currently overlooked risk factor contributing to TdP development in the general population. Methods Forty consecutive patients who experienced TdP (TdP cohort) were consecutively enrolled and circulating levels of C-reactive protein (CRP) and proinflammatory cytokines (interleukin-6 (IL-6), tumour necrosis factor alpha (TNFα), interleukin-1 (IL-1)) were compared with patients with active rheumatoid arthritis (RA), comorbidity or healthy controls. An additional 46 patients with different inflammatory conditions (acute infections, n=31; immune-mediated diseases, n=12; others, n=3) and elevated CRP (inflammatory cohort) were prospectively enrolled, and corrected QT (QTc) and cytokine levels were measured during active disease and after a CRP decrease of >75% subsequent to therapy. Results In the TdP cohort, 80% of patients showed elevated CRP levels (median: ∼3 mg/dL), with a definite inflammatory disease identifiable in 18/40 cases (acute infections, n=12; immune-mediated diseases, n=5; others, n=1). In these subjects, IL-6, but not TNFα and IL-1, was ∼15-20 times higher than in controls, and comparable to RA patients. In the inflammatory cohort, where QTc prolongation was common (mean values: 456.6±30.9 ms), CRP reduction was associated with IL-6 level decrease and significant QTc shortening (22.3 ms). Conclusion The data are first to show that systemic inflammation via elevated IL-6 levels may represent a novel QT-prolonging risk factor contributing to TdP occurrence in the presence of other classical risk factors. If confirmed, this could open new avenues in antiarrhythmic therapy