Pathological autoantibody internalisation in myositis.

OBJECTIVES: Autoantibodies targeting intracellular proteins are common in various autoimmune diseases. In the context of myositis, the pathologic significance of these autoantibodies has been questioned due to the assumption that autoantibodies cannot enter living muscle cells. This study aims to investigate the validity of this assumption. METHODS: Confocal immunofluorescence microscopy was employed to localise antibodies and other proteins of interest in myositis muscle biopsies. Bulk RNA sequencing was used to examine the transcriptomic profiles of 669 samples, including those from patients with myositis, disease controls and healthy controls. Additionally, antibodies from myositis patients were introduced into cultured myoblasts through electroporation, and their transcriptomic profiles were analysed using RNA sequencing. RESULTS: In patients with myositis autoantibodies, antibodies accumulated inside myofibres in the same subcellular compartment as the autoantigen. Bulk RNA sequencing revealed that muscle biopsies from patients with autoantibodies targeting transcriptional regulators exhibited transcriptomic patterns consistent with dysfunction of the autoantigen. For instance, in muscle biopsies from patients with anti-PM/Scl autoantibodies recognising components of the nuclear RNA exosome complex, an accumulation of divergent transcripts and long non-coding RNAs was observed; these RNA forms are typically degraded by the nuclear RNA exosome complex. Introducing patient antibodies into cultured muscle cells recapitulated the transcriptomic effects observed in human disease. Further supporting evidence suggested that myositis autoantibodies recognising other autoantigens may also disrupt the function of their targets. CONCLUSIONS: This study demonstrates that, in myositis, autoantibodies are internalised into living cells, causing biological effects consistent with the disrupted function of their autoantigen.

Nailfold capillaroscopy findings of a multicentric multi-ethnic cohort of patients with idiopathic inflammatory myopathies.

OBJECTIVES: To assess nailfold video capillaroscopic (NVC) abnormalities and their association with clinical features, myositis-specific autoantibodies (MSA), and myositis-associated antibodies (MAA) in a large multi-ethnic cohort of patients with idiopathic inflammatory myopathies (IIM). METHODS: We recruited 155 IIM patients from three centres in Mexico, Spain, and the USA. We evaluated the clinical and laboratory features of the patients and performed semiquantitative and quantitative analyses of the NVC. Each NVC study was defined as having a normal, non-specific, early systemic sclerosis (SSc), active SSc, or late SSc pattern. Twenty-three patients had at least one follow-up NVC when disease control was achieved. Quantitative variables were expressed as medians and interquartile range (IQR) and were compared with the Kruskal-Wallis, the Mann-Whitney U-test, and the Wilcoxon test for paired medians. Associations between qualitative variables were assessed with the χ2 test. RESULTS: Most patients were women (68.3%), Hispanic (73.5%), and had dermatomyositis (DM) (61.2%). Fourteen patients (9%) had a normal NVC. A non-specific abnormality pattern was the most frequent (53.9%), and was associated with joint involvement, interstitial lung disease, Jo1 autoantibodies, anti-synthetase syndrome, and immune-mediated necrotising myopathy. The SSc pattern was observed mostly in DM and overlap myositis and was associated with cutaneous features and anti-TIF-1g autoantibodies. After treatment, there was a decrease in the capillaroscopic score, the capillary diameter, and the number of avascular areas, and an increase in capillary density and bushy capillary number. CONCLUSIONS: NVC abnormalities are related to the diagnosis, clinical features, disease activity, and autoantibodies of patients with IIM.

Anti-synthetase and myelodysplastic syndromes with deep morphea: an example of shared immunopathogenesis? A case-based review.

Anti-synthetase syndrome (AS) is a subset of idiopathic inflammatory myopathy (IIM) characterized by the presence of anti-aminoacyl-transfer RNA synthetase accompanied by myositis, interstitial lung disease and other clinical features. According to a recent multicentric study, 31% of AS patients present skin lesions compatible with dermatomyositis, but sclerodermiform features are rare. Therefore, we aimed to report the case of a patient with simultaneous diagnosis of AS, deep morphea, vasculitic neuropathy, and myelodysplastic syndrome and review the current literature regarding these uncommon associations. A 57 year old man with axial and symmetrical proximal muscle weakness, skin thickening and B symptoms, later diagnosed with PL7 + AS, deep morphea, myelodysplastic syndrome (MDS) and vasculitic neuropathy documented by histopathologic studies and immunologic assessments. Since both AS and deep morphea share the vasculopathic changes and type II interferon-induced inflammation, we hypothesize that they may share pathogenic mechanisms. The muscle biopsy of the patient was consistent with AS and showed focal neutrophil infiltration. The patient received intensive immunosuppressive therapy for AS and vasculitic neuropathy, with high dose steroids, intravenous immunoglobulin (IVIg) and rituximab. Nonetheless, he suffered an unfavorable evolution with a fatal outcome due to septic shock. Albeit sclerodermiform features are rare in patients with AS, we propose a pathogenic link among AS, deep morphea and the autoimmune/autoinflammatory signs of MDS. The vasculopathic changes along with the activation of the innate and adaptive immune system leading to the production of proinflammatory cytokines may have been one of the contributing factors for the coexisting diagnosis of the patient.

Can we differentiate patients with dysferlinopathies and inflammatory myopathies by ultrasound? A discriminant analysis study.

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of diseases that are characterized by inflammation and muscle weakness. Dysferlinopathies are autosomal recessive limb-girdle muscular dystrophies caused by mutations in DYSF, which share a similar clinical presentation and histopathological inflammatory changes. To determine the sonographic differences between dysferlinopathies and IIM and whether these differences allow their classification. This observational, cross-sectional, and analytical study evaluated 20 muscles from 11 patients with dysferlinopathies and 11 patients with IIM. The patients were matched for age, sex, and disease duration. Clinical and laboratory variables were analyzed. Semi-quantitative scales were used to weigh the gray scale and power Doppler muscle abnormalities. Descriptive statistics were computed and discriminant analysis was performed to determine the ultrasound variables that best predicted the final diagnosis. Forty muscles were evaluated. Atrophy and higher Heckmatt scale scores were observed in patients with dysferlinopathies. A set of three muscles (biceps/brachialis, quadriceps, and gastrocnemius) had a diagnostic accuracy of 100% (sensitivity, 100%; specificity, 100%; canonical coefficient, 0.733 p < 0.001). A set of two formulas was used to classify both diseases correctly. In the present study, scanning of three muscle groups showed high diagnostic accuracy in differentiating dysferlinopathies from MII. Ultrasound can be used as an initial test in patients with suspected muscle disease or as an additional tool to support diagnosis in controversial cases.

Novel Clinical, Immunological, and Metabolic Features Associated with Persistent Post-Acute COVID-19 Syndrome.

The coronavirus disease 2019 (COVID-19) survivors are frequently observed to present persistent symptoms constituting what has been called "post-acute COVID-19 syndrome" (PACS) or "long COVID-19". Some clinical risk factors have been identified to be associated with PACS development; however, specific mechanisms responsible for PACS pathology remain unknown. This study investigates clinical, immunological, and metabolomic risk factors associated with post-acute COVID-19 syndrome (PACS) in 51 patients, assessed 7-19 months after acute infection. Among the participants, 62.7% were male and 37.2% were female, with an average age of 47.8 years. At the follow-up, 37.2% met the criteria for PACS, revealing significant differences in immunological and metabolomic profiles at the time of acute infection. Patients with PACS were characterized by elevated levels of mature low-density granulocytes (LDGs), interleukin-8 (IL-8), pyruvate, pseudouridine, and cystine. Baseline multivariate analysis showed increased pyruvate and decreased alpha tocopherol levels. At follow-up, there was a decrease in absolute B lymphocytes and an increase in non-classical monocytes and 3-hydroxyisovaleric acid levels. These findings suggest that specific immunological and metabolomic markers during acute infection can help identify patients at higher risk of developing persistent PACS.

Transcriptional derepression of CHD4/NuRD-regulated genes in the muscle of patients with dermatomyositis and anti-Mi2 autoantibodies.

OBJECTIVES: Myositis is a heterogeneous family of diseases including dermatomyositis (DM), immune-mediated necrotising myopathy (IMNM), antisynthetase syndrome (AS) and inclusion body myositis (IBM). Myositis-specific autoantibodies define different subtypes of myositis. For example, patients with anti-Mi2 autoantibodies targeting the chromodomain helicase DNA-binding protein 4 (CHD4)/NuRD complex (a transcriptional repressor) have more severe muscle disease than other DM patients. This study aimed to define the transcriptional profile of muscle biopsies from anti-Mi2-positive DM patients. METHODS: RNA sequencing was performed on muscle biopsies (n=171) from patients with anti-Mi2-positive DM (n=18), DM without anti-Mi2 autoantibodies (n=32), AS (n=18), IMNM (n=54) and IBM (n=16) as well as 33 normal muscle biopsies. Genes specifically upregulated in anti-Mi2-positive DM were identified. Muscle biopsies were stained for human immunoglobulin and protein products corresponding to genes specifically upregulated in anti-Mi2-positive muscle biopsies. RESULTS: A set of 135 genes, including SCRT1 and MADCAM1, was specifically overexpressed in anti-Mi2-positive DM muscle. This set was enriched for CHD4/NuRD-regulated genes and included genes that are not otherwise expressed in skeletal muscle. The expression levels of these genes correlated with anti-Mi2 autoantibody titres, markers of disease activity and with the other members of the gene set. In anti-Mi2-positive muscle biopsies, immunoglobulin was localised to the myonuclei, MAdCAM-1 protein was present in the cytoplasm of perifascicular fibres, and SCRT1 protein was localised to myofibre nuclei. CONCLUSIONS: Based on these findings, we hypothesise that anti-Mi2 autoantibodies could exert a pathogenic effect by entering damaged myofibres, inhibiting the CHD4/NuRD complex, and subsequently derepressing the unique set of genes defined in this study.

Transcriptomic profiling reveals distinct subsets of immune checkpoint inhibitor induced myositis.

OBJECTIVES: Inflammatory myopathy or myositis is a heterogeneous family of immune-mediated diseases including dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotising myopathy (IMNM) and inclusion body myositis (IBM). Immune checkpoint inhibitors (ICIs) can also cause myositis (ICI-myositis). This study was designed to define gene expression patterns in muscle biopsies from patients with ICI-myositis. METHODS: Bulk RNA sequencing was performed on 200 muscle biopsies (35 ICI-myositis, 44 DM, 18 AS, 54 IMNM, 16 IBM and 33 normal muscle biopsies) and single nuclei RNA sequencing was performed on 22 muscle biopsies (seven ICI-myositis, four DM, three AS, six IMNM and two IBM). RESULTS: Unsupervised clustering defined three distinct transcriptomic subsets of ICI-myositis: ICI-DM, ICI-MYO1 and ICI-MYO2. ICI-DM included patients with DM and anti-TIF1γ autoantibodies who, like DM patients, overexpressed type 1 interferon-inducible genes. ICI-MYO1 patients had highly inflammatory muscle biopsies and included all patients that developed coexisting myocarditis. ICI-MYO2 was composed of patients with predominant necrotising pathology and low levels of muscle inflammation. The type 2 interferon pathway was activated both in ICI-DM and ICI-MYO1. Unlike the other types of myositis, all three subsets of ICI-myositis patients overexpressed genes involved in the IL6 pathway. CONCLUSIONS: We identified three distinct types of ICI-myositis based on transcriptomic analyses. The IL6 pathway was overexpressed in all groups, the type I interferon pathway activation was specific for ICI-DM, the type 2 IFN pathway was overexpressed in both ICI-DM and ICI-MYO1 and only ICI-MYO1 patients developed myocarditis.

Peripheral expansion of myeloid-derived suppressor cells is related to disease activity and damage accrual in inflammatory myopathies.

OBJECTIVE: To assess the proportion of myeloid-derived suppressor cells (MDSCs), their expression of arginase-1 and programmed cell death ligand 1 (PD-L1) and their relationship with the clinical phenotype of patients with idiopathic inflammatory myopathies (IIMs). METHODS: We recruited 37 IIM adult patients and 10 healthy donors in Mexico City. We evaluated their clinical features, the proportion of MDSCs and their expression of PD-L1 and arginase-1 by flow cytometry. Polymorphonuclear (PMN)-MDSCs were defined as CD33dim, CD11b+ and CD66b+ while monocytic (M)-MDSCs were CD33+, CD11b+, HLA-DR- and CD14+. Serum cytokines were analysed with a multiplex assay. We compared the quantitative variables with the Kruskal-Wallis and Mann-Whitney U tests and assessed correlations with Spearman's ρ. RESULTS: Most patients had dermatomyositis [n = 30 (81.0%)]. IIM patients had a peripheral expansion of PMN-MDSCs and M-MDSCs with an enhanced expression of arginase-1 and PD-L1. Patients with active disease had a decreased percentage {median 1.75% [interquartile range (IQR) 0.31-5.50 vs 10.71 [3.16-15.58], P = 0.011} of M-MDSCs and a higher absolute number of PD-L1+ M-MDSCs [median 23.21 cells/mm3 (IQR 11.16-148.9) vs 5.95 (4.66-102.7), P = 0.046] with increased expression of PD-L1 [median 3136 arbitrary units (IQR 2258-4992) vs 1961 (1885-2335), P = 0.038]. PD-L1 expression in PMN-MDSCs correlated with the visual analogue scale of pulmonary disease activity (r = 0.34, P = 0.040) and damage (r = 0.36, P = 0.031), serum IL-5 (r = 0.55, P = 0.003), IL-6 (r = 0.46, P = 0.003), IL-8 (r = 0.53, P = 0.018), IL-10 (r = 0.48, P = 0.005) and GM-CSF (r = 0.48, P = 0.012). M-MDSCs negatively correlated with the skeletal Myositis Intention to Treat Index (r = -0.34, P = 0.038) and positively with IL-6 (r = 0.40, P = 0.045). CONCLUSION: MDSCs expressing arginase-1 and PD-L1 are expanded in IIM and correlate with disease activity, damage accrual and serum cytokines.

Systemic inflammation and cortical neurochemistry in never-medicated first episode-psychosis individuals.

Studies of cellular and cytokine profiles have contributed to the inflammation hypothesis of schizophrenia; however, precise markers of inflammatory dysfunction remain elusive. A number of proton magnetic resonance spectroscopy (1H-MRS) studies in patients with first-episode psychosis (FEP) have shown higher brain levels of metabolites such as glutamate, myo-inositol (mI) and choline-containing compounds (tCho), suggesting neuroinflammation. Here, we present peripheral inflammatory profiles in antipsychotic-naive FEP patients and age-and-sex matched healthy controls, as well as cortical glutamate, mI and tCho levels using 1H-MRS. Inflammatory profiles were analyzed using cytokine production by peripheral blood mononuclear cells, that were either spontaneous or stimulated, in 48 FEP patients and 23 controls. 1H-MRS of the medial prefrontal cortex was obtained in 29 FEP patients and 18 controls. Finally, 16 FEP patients were rescanned after 4 weeks of treatment (open-label) with Risperidone. FEP patients showed a higher proportion of proinflammatory Th1/Th17 subset, and an increased spontaneous production of Interleukin (IL)-6, IL-2 and IL-4 compared with the control group. Results obtained from 1H-MRS showed no significant difference in either glutamate, mI or tCho between FEP and control groups. At baseline, CD8% showed a negative correlation with glutamate in FEP patients; after 4 weeks of risperidone treatment, the FEP group exhibited a decrease in glutamate levels which positively correlated with CD4 + T cells. Nevertheless, these correlations did not survive correction for multiple comparisons. FEP patients show evidence of immune dysregulation, affecting both the innate and adaptive immune response, with a predominantly Th2 signature. These findings, along with the changes produced by antipsychotic treatment, could be associated with both systemic and central inflammatory processes in schizophrenia.

Colchicine Is Safe Though Ineffective in the Treatment of Severe COVID-19: a Randomized Clinical Trial (COLCHIVID).

BACKGROUND: Colchicine is an available, safe, and effective anti-inflammatory drug and has been suggested as a COVID-19 treatment, but its usefulness in hospitalized severe COVID-19 patients has not been thoroughly demonstrated. OBJECTIVE: To address the safety and efficacy of colchicine in hospitalized patients with severe COVID-19. DESIGN: We conducted a triple-blind parallel non-stratified placebo-controlled clinical trial. PARTICIPANTS: We recruited 116 hospitalized patients with severe COVID-19 in Mexico. INTERVENTIONS: Patients were randomized to receive 1.5 mg of colchicine or placebo at the time of the recruitment in the study (baseline) and 0.5 mg BID PO to complete 10 days of treatment. MAIN MEASURES: The primary composite outcome was the progression to critical disease or death. Besides, we evaluated immunological features at baseline and after recovery or disease progression in 20 patients. KEY RESULTS: Fifty-six patients were allocated to colchicine and 60 patients received placebo. The study was suspended after the second interim analysis demonstrated colchicine had no effect on the primary outcome (OR 0.83, 95%CI 0.35-1.93, P = 0.67), nor in the days of ICU and hospital stays. Adverse events were similar between groups (OR 1.63, 95% CI 0.66-3.88, P = 0.37). After colchicine treatment, patients had higher BUN and lower serum levels of IL-8, IL-12p70, and IL-17A. CONCLUSIONS: Colchicine is safe but not effective in the treatment of severe COVID-19. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04367168.