Cutting edge issues in polymyositis

Liver failure as the initial presentation in cancer of unknown primary: a case report

BACKGROUND

Liver failure is severe hepatic cellular damage caused by multiple factors that leads to clinical manifestations. Hepatic infiltration by malignancy is rarely reported as a cause of liver failure.

CASE PRESENTATION

A 51-year-old male patient was admitted to the Wuhan Union Hospital complaining of bloating and jaundice. He had been diagnosed with polymyositis ten prior and was taking oral glucocorticoids. Physical examination revealed seroperitoneum and icteric sclera; laboratory tests revealed liver dysfunction, a coagulopathy, and negative results for the common causes of liver failure. Moreover, an ascitic tap and bone marrow aspirate and trephine confirmed a metastatic, poorly differentiated adenocarcinoma. These findings indicate that malignant infiltration is the most likely cause of liver failure. Regrettably, the patient refused complete liver and lymph node biopsies and was discharged on day 31.

CONCLUSION

Clinicians should consider the possibility of malignant infiltration when approaching a case of liver failure with prodromal symptoms or imaging abnormalities, especially in patients with autoimmune diseases, such as polymyositis.

NLRP3 inflammasome up-regulates major histocompatibility complex class I expression and promotes inflammatory infiltration in polymyositis

Objective

This study was designed to investigate the role of the nucleotide-binding-domain -and leucine-rich repeat -containing (NLR) family, pyrin-domain-containing 3 (NLRP3) inflammasome in the pathogenesis of polymyositis (PM).

Methods

Immunochemistry was performed to analyze the NLRP3, caspase-1 and interleukin-1 beta (IL-1β) expression in the muscle tissue of PM patients. Rat model of PM and C2C12 cell were used to investigate the potential role of NLRP3 inflammasome in PM.

Results

The percentage of CD 68+ macrophages, and the expression levels of NLRP3, caspase-1 and IL-1β in the muscle tissue were elevated in 27 PM patients. LPS/ATP treatment resulted in activation of NLRP3 inflammasome and secretion of IL-1β as well as interferons (IFNs) and monocyte chemotactic protein-1 (MCP-1) in the Raw 264.7 macrophages. Meanwhile, LPS/ATP challenged activation of NLRP3 inflammasome induced overexpression of major histocompatibility complex class I (MHC-I), a key molecular of PM in the co-cultured C2C12 cells. The effect was decreased by treatment of NLRP3 inflammasome inhibitor MCC950 or siRNA of NLRP3 inflammasome. These findings suggested certain levels of IL-1β rather than IFNs up-regulated MHC-I expression in C2C12 cells. IL-1β blockade using neutralizing IL-1β monoclonal antibody or siRNA of IL-1β suppressed MHC-I overexpression. In vivo, NLRP3 inflammasome inhibition by MCC950 reduced the expression of NLRP3, IL-1β and MHC-I in the muscle tissue of PM modal rats. Also, it attenuated the intensity of muscle inflammation as well as the CRP, CK, and LDH levels in the serum.

Conclusion

NLRP3/caspase-1/IL-1β axis may play an important role in the development of PM. Inhibition of NLRP3 activation may hold promise in the treatment of PM.

Dermatomyositis: immunological landscape, biomarkers, and potential candidate drugs

INTRODUCTION

Dermatomyositis (DM) is a rare inflammatory disease characterized by the invasion of the skin and muscles. Environmental, genetic, and immunological factors contribute to disease pathology. To date, no bioinformatics studies have been conducted on the potential pathogenic genes and immune cell infiltration in DM. Therefore, we aimed to identify differentially expressed genes (DEGs) and immune cells, as well as potential pathogenic genes and immune characteristics, which may be useful for the diagnosis and treatment of DM.

METHOD

GSE1551, GSE5370, GSE39454, and GSE48280 from Gene Expression Omnibus were included in our study. Limma, ClusterProfiler, and Kyoto Encyclopedia of Genes and Genomes were used to identify DEGs, Gene Ontology (GO), and perform pathway analyses, respectively. Cytoscape was used to construct the protein-protein interaction (PPI) network. Small-molecule drugs were identified using a connectivity map (CMap), and the TIMER database was used to identify infiltrating cells.

RESULTS

DEG analysis identified 12 downregulated and 163 upregulated genes. GO analysis showed that DEGs were enriched in immune-related pathways. Ten hub genes were identified from the PPI network. Additionally, CMap analysis showed that caffeic acid, sulfaphenazole, molindone, tiabendazole, and bacitracin were potential small-molecule drugs with therapeutic significance. We identified eight immune cells with differential infiltration in patients with DM and controls. Finally, we constructed a powerful diagnostic model based on memory B cells, M1, and M2 macrophages.

CONCLUSIONS

This study explored the potential molecular mechanism and immunological landscape of DM and may guide future research and treatment of DM.

KEY POINTS

• We explored the molecular mechanism and immunological landscape of dermatomyositis. • GO analysis showed that DEGs were enriched in immune-related pathways. • We predicted small-molecular drugs with potential therapeutic significance based on bioanalytical techniques. • We identified six immune cells with differential infiltration in patients with DM and controls.

A New Immunodot Assay for Multiplex Detection of Autoantibodies in a Cohort of Italian Patients With Idiopathic Inflammatory Myopathies

BACKGROUND

Autoantibody detection has been assessed as tool for the diagnosis and the definition of idiopathic inflammatory myopathies (IIM). The aim of the study was to characterize the autoantibody profiling of a cohort of Italian patients with IIM.

METHODS

Sera of 53 adult patients with definite IIM, according to Bohan-Peter criteria, were tested for anti-nuclear autoantibodies (ANA), using indirect immunofluorescence (IIF) method, and for myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), using two new commercial immunodot assays.

RESULTS

MSAs and/or MAAs were detected in 29 of 53 (54.7%) patients with IIM. Twenty-three patients (43.4%) were positive for at least one MSAs: 13 (24.5%) had anti-histidyl-tRNA synthetase autoantibodies (Jo1), 4 (7.5%) had other anti-aminoacyl-tRNA synthetases autoantibodies (anti-ARS), 1 (1.8%) had anti-transcription intermediary factor 1 gamma autoantibodies (anti-TIF1γ), 2 (3.7%) had anti-nuclear helicase protein Mi-2 autoantibodies (anti-Mi-2), 4 (7.5%) had anti-small ubiquitin like modifier activating enzyme heterodimer autoantibodies (anti-SAE). Moreover, 17 patients (32%) were positive for at least one MAAs. Coexisting MSAs and MAAs were observed in 9 of 53 (16.9%) patients, anti-Jo1/SS-A autoantibodies in most cases. Overall sensitivity of immunodot assays was 54.7%, the specificity was almost absolute. At cut-off value of 1:160, the sensitivity of ANA-IIF was 52.8%, increasing to 66% if cytoplasmatic fluorescence reaction was reported. Notably, two (5.7%) ANA-IIF negative patients had MSAs, detected only by immunodot assays.

CONCLUSION

It was possible to identify MSAs otherwise undetectable because of the use of new assays. Immunodot can reveal MSAs even when IIF results are inconclusive or, in some cases, ANA negative.

Macrophage plasticity in skeletal muscle repair

Macrophages are one of the first barriers of host defence against pathogens. Beyond their role in innate immunity, macrophages play increasingly defined roles in orchestrating the healing of various injured tissues. Perturbations of macrophage function and/or activation may result in impaired regeneration and fibrosis deposition as described in several chronic pathological diseases. Heterogeneity and plasticity have been demonstrated to be hallmarks of macrophages. In response to environmental cues they display a proinflammatory (M1) or an alternative anti-inflammatory (M2) phenotype. A lot of evidence demonstrated that after acute injury M1 macrophages infiltrate early to promote the clearance of necrotic debris, whereas M2 macrophages appear later to sustain tissue healing. Whether the sequential presence of two different macrophage populations results from a dynamic shift in macrophage polarization or from the recruitment of new circulating monocytes is a subject of ongoing debate. In this paper, we discuss the current available information about the role that different phenotypes of macrophages plays after injury and during the remodelling phase in different tissue types, with particular attention to the skeletal muscle.

Clinical guidelines and definitions of autoinflammatory diseases: contrasts and comparisons with autoimmunity-a comprehensive review

Autoinflammatory diseases (AIDs) and autoimmune diseases (ADs) are characterized by an aberrant chronic activation of the immune system which causes tissue inflammation and damage in genetically predisposed individuals. Pathogenetic mechanisms underlying this damage differ between these two types of diseases; in AIDs, the innate immune system is directly responsible for tissue inflammation, while in ADs it works by activating the adaptive immune system, which becomes the main effector of the inflammatory process. Despite the fact that AIDs have only been recently defined, they are older than ADs. The innate immune system is found in plants and animals, and it developed earlier than the adaptive immune system, which first appeared in jawed vertebrates. According to genetic background and clinical, serological, and radiological findings, AIDs and ADs might be considered as a single spectrum of disorders, with a wide range of manifestations. Indeed, autoinflammatory-like diseases have been reported in simple organisms such as Drosophila melanogaster and Caenorhabditis elegans. We analyzed here the main pathogenetic and clinical features of these two groups of diseases mostly dealing with their similarities and differences.

Statistical insights into major human muscular diseases

Muscular diseases lead to muscle fiber degeneration, impairment of mobility, and in some cases premature death. Many of these muscular diseases are largely idiopathic. The goal of this study was to identify biomarkers based on their functional role and possible mechanisms of pathogenesis, specific to individual muscular disease. We analyzed the muscle transcriptome from five major muscular diseases: acute quadriplegic myopathy (AQM), amyotrophic lateral sclerosis (ALS), mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), dermatomyositis (DM) and polymyositis (PM) using pairwise statistical comparison to identify uniquely regulated genes in each muscular disease. The genome-wide information encoded in the transcriptome provided biomarkers and functional insights into dysregulation in each muscular disease. The analysis showed that the dysregulation of genes in forward membrane pathway, responsible for transmitting action potential from neural excitation, is unique to AQM, while the dysregulation of myofibril genes, determinant of the mechanical properties of muscle, is unique to ALS, dysregulation of ER protein processing, responsible for correct protein folding, is unique to DM, and upregulation of immune response genes is unique to PM. We have identified biomarkers specific to each muscular disease which can be used for diagnostic purposes.

Inclusion body myositis associated with Sjögren's syndrome

Inclusion body myositis (IBM) belongs to the group of idiopathic inflammatory myopathies. It is a poorly understood disease, which affects skeletal muscles. IBM usually occurs as an isolated condition, but in some cases, it may be associated with another autoimmune disorder, Sjögren’s syndrome. We report a case of a 47-year-old woman with headaches, symptoms of trigeminal neuralgia, progressive weakness in muscles of the upper and lower extremities and symptoms of dry eyes and mouth. On admission, creatine kinase level was increased to 6,956 IU/mL and lactate dehydrogenase (LDH) to 1,011 U/L in the serum. The increase in inflammatory factor (CRP, ESR) levels was not found. The diagnosis of inclusion body myositis associated with Sjögren’s syndrome was established on the basis of clinical picture and diagnostic tests. In this therapy, methotrexate and methylprednisolone were administered. The considerable improved muscle strength in the upper and lower extremities, improved speech and swallowing, disappearance of headache and reduction in CPK and LDH levels were found 8 months after establishing the diagnosis. Treatment with methotrexate and methylprednisolone improved the clinical symptoms and quality of life of this patient and may offer a therapeutic option for some patients with IBM and concomitant Sjögren’s syndrome.

Overlap connective tissue disease syndromes

Overlap Syndromes (OSs) have been defined as entities satisfying classification criteria of at least two connective tissue diseases (CTDs) occurring at the same or at different times in the same patient. CTDs include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PDM), and Sjögren syndrome (SS). Every combination between these disorders has been reported. In some OS a specific autoantibody has been indentified, supporting the hypothesis that these syndromes are not a mere association of two or more CTD in the same patient, but a well defined clinical entity with specific clinical characteristics. As an example, anti-t-RNA synthetase syndrome is characterized by the presence of anti-t-RNA synthetase antibodies. Notably, clinical manifestations observed in OS may be different from those observed in the single CTD. The treatment of OS is mainly based on the use of corticosteroids and immunosuppressants. Biologic drugs, i.e. anti-TNFα or anti-CD20 monoclonal antibodies, have been recently introduced as alternative treatments in refractory cases. Moreover, there are some concerns with the use of anti-TNF agents in patients with systemic autoimmune diseases due to the risk of triggering disease exacerbations. In this paper the most frequent OS are described with a special focus on the specific immunologic and clinical aspects. Furthermore, some personal data on anti-t-RNA synthetase syndrome and rhupus syndrome are reported.

Interstitial lung disease outcomes by high-resolution computed tomography (HRCT) in Anti-Jo1 antibody-positive polymyositis patients: a single centre study and review of the literature

Interstitial lung disease (ILD) is a frequent complication of inflammatory myopathies with high rates of morbidity and mortality. Antibodies against aminoacyl-tRNA-synthetases are the strongest predictive factors in ILD. In this study, we reviewed the literature and we retrospectively analysed high-resolution computed tomography (HRCT) findings in a cohort of 131 consecutive subjects: 75 with polymyositis (PM), 43 with dermatomyositis (DM), one with amyophatic PM, two with paraneoplastic syndromes, and 10 with overlapping syndromes. The inclusion criteria were PM/DM, anti-Jo1 antibody positivity, and HRCT-assessed ILD. The effect of 12 months' treatment with cyclophosphamide (CYC) or cyclosporin A (CsA) plus steroids was assessed by comparing baseline and follow-up HRCT scans for evidence of stability, improvement or worsening. Fifteen patients (11.5%) had ILD and were Jo-1 positive. They were all women with PM, and had a mean age of 47.33 years and a median duration of symptoms of 7.26 months. At baseline, HRCT showed ground-glass attenuations in eight cases, septal thickening in seven, and honeycombing in four. Twelve months after diagnosis, ILD had worsened in nine patients (60%; exact confidence interval [ECI] 32-84) and was stable in four (two patients were lost to follow-up). Seven of the 15 patients were treated with CsA, and 12-month HRCT revealed a worsening in ILD in five cases (71%; ECI 0.29-0.96); ILD also worsened (ECI 16-84) in four of the eight patients treated with CYC pulses (50%). The evolution of the HRCT findings was not significantly different between the two groups. Our findings confirm that ILD is a common early manifestation in patients with Jo1-positive PM. Over twelve months, HRCT showed worsening ILD in most of our patients, with no difference in the HRCT changes between those treated with CYC or CsA.