interleukin-8 and Polymyositis

Myositis is a heterogeneous family of diseases that includes dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotising myopathy (IMNM), inclusion body myositis (IBM), polymyositis and overlap myositis. Additional subtypes of myositis can be defined by the presence of myositis-specific autoantibodies (MSAs). The purpose of this study was to define unique gene expression profiles in muscle biopsies from patients with MSA-positive DM, AS and IMNM as well as IBM.. RNA-seq was performed on muscle biopsies from 119 myositis patients with IBM or defined MSAs and 20 controls. Machine learning algorithms were trained on transcriptomic data and recursive feature elimination was used to determine which genes were most useful for classifying muscle biopsies into each type and MSA-defined subtype of myositis.. The support vector machine learning algorithm classified the muscle biopsies with >90% accuracy. Recursive feature elimination identified genes that are most useful to the machine learning algorithm and that are only overexpressed in one type of myositis. For example, CAMK1G (calcium/calmodulin-dependent protein kinase IG), EGR4 (early growth response protein 4) and CXCL8 (interleukin 8) are highly expressed in AS but not in DM or other types of myositis. Using the same computational approach, we also identified genes that are uniquely overexpressed in different MSA-defined subtypes. These included apolipoprotein A4 (APOA4), which is only expressed in anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) myopathy, and MADCAM1 (mucosal vascular addressin cell adhesion molecule 1), which is only expressed in anti-Mi2-positive DM.. Unique gene expression profiles in muscle biopsies from patients with MSA-defined subtypes of myositis and IBM suggest that different pathological mechanisms underly muscle damage in each of these diseases.

Topics: Adult; Animals; Apolipoproteins A; Autoimmune Diseases; Biopsy; Calcium-Calmodulin-Dependent Protein Kinase Type 1; Cell Adhesion Molecules; Cell Culture Techniques; Dermatomyositis; Early Growth Response Transcription Factors; Female; Humans; Hydroxymethylglutaryl CoA Reductases; Interleukin-8; Machine Learning; Male; Mice; Mucoproteins; Muscle, Skeletal; Muscular Diseases; Myositis; Myositis, Inclusion Body; Polymyositis; Transcriptome

PM and DM are often complicated by interstitial lung disease (ILD). In this study we aimed to evaluate various serum cytokines in patients with PM/DM with ILD so as to clarify the differences in pathophysiology between anti-melanoma differentiation-associated gene 5 antibody-associated ILD (anti-MDA5-ILD) and anti-aminoacyl tRNA synthetase antibody-associated ILD (anti-ARS-ILD).. We evaluated the serum cytokine profiles of 38 patients with PM/DM and compared the cytokine profiles of the non-ILD and ILD subsets as well as the anti-MDA5-ILD and anti-ARS-ILD subsets.. The myositis intention-to-treat activity index score, which indicates whole disease activity, significantly correlated with serum IL-6, IL-8, TNF-α and IP-10. These cytokine levels were significantly higher in the ILD subset than the non-ILD subset and were lower in the ILD subset following treatment. By multivariate analysis, TNF-α was the most significant cytokine [P = 0.0006, odds ratio (OR) 1.4, CI 1.1, 2.2] associated with PM/DM with ILD. IL-8 levels were significantly higher in anti-MDA5-ILD than in anti-ARS-ILD, although IL-6, TNF-α and IP-10 levels were high in both subsets. IL-8 was the most significant cytokine (P = 0.0006, OR 1.5, CI 1.1, 3.0) associated with anti-MDA5-ILD by multivariate analysis. Moreover, the ratio of IL-4 to IFN-γ was lower in anti-MDA5-ILD than in anti-ARS-ILD.. IL-6, IL-8, TNF-α and IP-10 are associated with global disease activity in PM/DM. These cytokine levels were high, especially in the ILD subset. Serum IL-8 levels and the balance between IL-4 and IFN-γ may contribute to the differences in pathophysiology between anti-ARS-ILD and anti-MDA5-ILD.

Topics: Adult; Chronic Disease; Cytokines; Dermatomyositis; Disease Progression; Female; Humans; Interleukin-6; Interleukin-8; Lung Diseases, Interstitial; Male; Middle Aged; Polymyositis; Prognosis; Retrospective Studies; Severity of Illness Index; Tumor Necrosis Factor-alpha

In polymyositis (PM)/dermatomyositis (DM), T cells infiltrate the muscle tissues and interact with muscle cells via cell surface molecules. Recently, myoblasts have been reported to express CD40, but little is known about the role of CD40 in myoblasts. In the present study we examined the expression and involvement of CD40 and CD40 ligand (CD40L) in the interaction between muscle cells and T cells in PM/DM. Immunohistochemical staining revealed that CD40 was expressed on muscle cells in five of five PM and four of five DM patients, and that infiltrating mononuclear cells (MNCs) expressed CD40L in all cases of PM/DM. These CD40L-expressing MNCs were primarily CD4+ T cells. IFN-gamma, which is known to induce CD40 expression on various types of cells, was also expressed on the MNCs in four of the PM and four of the DM patients. Although cultured human myoblasts (SkMC 2859) did not express CD40 constitutively, IFN-gamma induced CD40 expression in a dose-dependent manner. To clarify the functional roles of CD40-mediated signals, the effects of a trimeric form of recombinant human CD40L on cytokine production were studied in SkMC 2859 that were prestimulated with IFN-gamma to express CD40. Recombinant human CD40L markedly increased the production of IL-6, IL-8, IL-15, and monocyte chemoattractant protein-1 of SkMC 2859. The expression of these humoral factors in muscle cells of PM and DM was demonstrated by immunohistochemistry. These results suggest that interaction between T cells and muscle cells via the CD40-CD40L system contributes to the immunopathogenesis of PM/DM by augmenting inflammation via cytokine production by the muscle cells.

Topics: Adjuvants, Immunologic; Adult; Aged; CD4-Positive T-Lymphocytes; CD40 Antigens; CD40 Ligand; CD8-Positive T-Lymphocytes; Cell Line; Cell Movement; Chemokine CCL2; Dermatomyositis; Female; Humans; Immune Sera; Infant; Interferon-gamma; Interleukin-15; Interleukin-6; Interleukin-8; Interleukins; Leukocytes, Mononuclear; Ligands; Male; Membrane Glycoproteins; Middle Aged; Muscle, Skeletal; Polymyositis; Recombinant Proteins