Autoantibodies in Polymyositis and Dermatomyositis

Abstract

Inflammatory myopathies are a group of acquired diseases, characterized by immunoflogistic processes primarily involving the skeletal muscle. According to recent classification criteria, four major diseases have been identified: polymyositis (PM), dermatomyositis (DM), sporadic inclusion body myositis (IBM), and necrotizing autoimmune myositis (NAM). Autoantibodies can be found in the sera of most patients with myositis. Myositis-specific autoantibodies (MSAs) are markers of very specific disease entities within the spectrum of myositis, and target proteins involved in key processes of protein synthesis. Myositis autoantigens comprise the well-defined aminoacyl-tRNA synthetases, the Mi-2 helicase/histone deacetylase protein complex, and the signal recognition particle (SRP) ribonucleoprotein, together with novel targets such as TIF1-γ, MDA5, NXP2, SAE, and HMGCR. Recent studies suggest that autoantigens drive a B cell antigen-specific immune response in muscles. Interestingly, an increased expression of Jo-1 and Mi-2 in regenerating fibers in muscle biopsies from PM and DM patients compared to normal was demonstrated. Myositis autoantigen up-regulation was observed in neoplastic tissues, thus representing a potential link between cancer and autoimmunity in myositis. Non-immunological mechanisms seem to participate to the pathogenesis of inflammatory myopathies; induction of endoplasmic reticulum stress response in response to abnormal muscle regeneration and inflammation has recently been reported in patients with myositis. This review article provides an update of new emerging insights about the clinical and pathophysiologic role of principal autoantibodies in myositis.

Galectin-3 in autoimmunity and autoimmune diseases

“…69 Polymyositis is characterized by a CD8 þ T-cell response against muscle antigens presented by MHC Class I molecules. On the other hand, dermatomyositis is marked by a complement-mediated microangiopathy, typically mediated by type I IFN phenotype and autoantibodies with distinct specificities 70,71 ; however, the exact mechanism involved in complement activation remains unclear. 72 Current biological treatments in polymyositis/dermatomyositis include blockade of cells and cytokines, including B-cells by rituximab, 73 T cells by abatacept and cytokines by anti-IL-1, anti-IL-6 or anti-IFNa monoclonal antibodies.…”

Ocena EKG i parametrów holterowskich u pacjentów z zapaleniem wielomięśniowym i skórno-mięśniowym

“…This may have been caused by either a different panel of circulating antibodies as compared to e.g. SLE or by a completely different pathomechanism of neuropathies in these diseases [8]. We did not observe any signifi cant differences in either the occurrence of ventricular extra beats or QT/QTc interval in both groups (Table 2).…”

“…There is some evidence that in PM and/or DM, such antibodies as anti-SRP and anti-HMGCR are identifi ed, and they could disturb the functions of the autonomic nervous system by affecting its structural components directly or indirectly [8]. However, we analysed SDDNi, SDANN, rMSSD, pNN50, VLF, LF, HF and we did not observe any statistically signifi cant differences between the study and control groups (Table 1).…”

Diagnostic criteria for idiopathic inflammatory myopathies. Problems of their optimization

“…4), которая ба-зируется на оценке аутоантител, играющих важную роль в патогенезе. Серологическая характеристика ИВМ опреде-ляет фенотипические субтипы пациентов, которые разли-Таблица 3. чаются как по дебюту и течению болезни, так по ответу на терапию ГК [32,33]. Наиболее изученными генетически-ми маркерами ИВМ являются HLA аллели.…”