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Pathophysiology of polymyositis. Polymyositis is characterized by an overexpression of major histocompatibility complex (MHC) class 1 antigens on muscle fibers and the infiltration of CD8 ? T cells from the periphery into the endomysium. Muscle fiber death occurs when an antigen-specific CD8 ? T cell binds its corresponding MHC-1 expressing antigen on a muscle fiber, activating the CD8 ? T cell to release perforin and granzyme granules and resulting in necrosis. Pro-inflammatory cytokines (e.g., interferon-c, tumor necrosis factor-a) released by the activated T cells may also enhance MHC-1 upregulation and the cytotoxic effect of T cells. Figure created with BioRender.com. CD40 indicates cluster of differentiation 40; CD40L, cluster of differentiation 40 ligand; CD80, cluster of differentiation 80; CTLA-4, cytotoxic T lymphocyte associated protein 4; ICAM-1, intercellular adhesion molecule 1; ICOS, inducible costimulator; ICOS-L, inducible costimulator-ligand; LFA-1, lymphocyte function-associated antigen 1; MHC, major histocompatibility complex; TCR, T cell receptor; VCAM-1, vascular cell adhesion protein 1; VLA-4, very late antigen-4
Source publication
Idiopathic inflammatory myopathies (IIMs) are autoimmune disorders characterized by symmetric proximal muscle weakness and chronic inflammation, with an increased risk of morbidity and mortality. The current standard of care includes traditional immunosuppressive pharmacotherapies; however, some patients cannot tolerate or do not adequately respond...
Context in source publication
Context 1
... characterized by endomysial inflammation [2] and muscle fiber degeneration [1]; however, the mechanism by which this occurs is not well established. Muscle biopsies from individuals with PM show an overexpression of major histocompatibility complex (MHC) class 1 antigens on muscle fibers, infiltration of CD8 ? T cells, and muscle fiber necrosis (Fig. 2) [2,19]. Muscle fiber death occurs when an antigenspecific CD8 ? T cell binds to its corresponding MHC-1 expressing antigen on a muscle fiber, activating the CD8 ? T cell to release perforin and granzyme granules that ultimately result in cell death [2]. Pro-inflammatory cytokines (e.g., interferon-c, tumor necrosis factor-a) released ...
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Purpose of review:
Idiopathic inflammatory myopathies (IIMs) are a group of rare autoimmune disorders characterized by muscle weakness and inflammation. MicroRNAs (miRNAs) are the main class of small noncoding RNAs regulating a wide range of physiological and pathological processes and play a role in mediating autoimmunity and inflammation. In thi...
Background
Juvenile dermatomyositis (JDM) is an uncommon inflammatory myopathy predominantly affecting children under 18 years of age. Diagnosis relies on identifying specific clinical features, such as muscle weakness, skin rash, elevated muscle enzymes, and MRI and muscle biopsy findings. Autoantibodies associated with inflammatory myopathy offer...
Dermatomyositis (DM) is an autoimmune disorder characterized by proximal muscle weakness and distinct cutaneous features. Unfortunately, infection is a frequent and potentially life-threatening complication in patients with DM. Here, we present a case of pyomyositis in a patient with DM resulting from localized cellulitis. The patient also presente...
Citations
... Acthar ® Gel (repository corticotropin injection) is a prime example of how the application of a highly purified fraction of ACTH(1-39) [102] has shown significant promise in IMID treatment, showing itself as an adjunctive therapy in rheumatoid arthritis (in patients with inadequate response to glucocorticoids or disease-modifying antirheumatic drugs), in the treatment of patients with persistently active systemic lupus erythematosus as well as in patients with dermatomyositis and polymyositis [103]. This gel, in addition to having a steroidogenic effect (i.e., able to act by promoting steroidogenesis through the MC2R receptor), is also able to exert immunomodulatory effects independently of this pathway (at the level of macrophages and B, T lymphocytes) [104]. In the case of this gel, the safety profile should also be weighed when implementing future IBD studies. ...
The melanocortin system is a complex set of molecular mediators and receptors involved in many physiological and homeostatic processes. These include the regulation of melanogenesis, steroidogenesis, neuromodulation and the modulation of inflammatory processes. In the latter context, the system has assumed importance in conditions of chronic digestive inflammation, such as inflammatory bowel diseases (IBD), in which numerous experiences have been accumulated in mouse models of colitis. Indeed, information on how such a system can counteract colitis inflammation and intervene in the complex cytokine imbalance in the intestinal microenvironment affected by chronic inflammatory damage has emerged. This review summarises the evidence acquired so far and highlights that molecules interfering with the melanocortin system could represent new drugs for treating IBD.
