Interleukin-35: A Serological Biomarker for Patients with Polymyositis/Dermatomyositis

Increased expression of the p-STAT3/IL-17 signaling pathway in patients with dermatomyositis

OBJECTIVES

The aim is to explore the roles of phosphorylated signal transduction and activator of transcription 3 (p-STAT3) and interleukin (IL)-17 in patients with dermatomyositis (DM).

METHODS

A total of 20 DM patients and 12 healthy controls were enrolled. Flow cytometry combined with counting was used to detect the number of Th17 cells. Western blotting and immunohistochemistry were used to examine the muscle levels of p-STAT3 and IL-17, and serum levels of IL-17 were measured by enzyme-linked immunosorbent assays.

RESULTS

Muscle p-STAT3 and IL-17 levels, the number of Th17 cells, and serum IL-17 levels were markedly increased in DM. p-STAT3 and IL-17 were co-expressed in the muscle of DM patients. The p-STAT3 levels were correlated with the number of Th17 cells as well as muscle and serum IL-17 levels. The correlations of the p-STAT3 level with elevated levels of transaminases, myocardial enzymes, and the health assessment questionnaire score were significantly positive, while the correlation with manual muscle testing-8 was significantly negative. A receiver operating characteristic curve indicated the good predictive value of p-STAT3 for the occurrence of DM.

CONCLUSIONS

The increased p-STAT3/IL-17 signaling pathway activation in DM patients may induce muscle inflammation and necrosis, and it may be a potential target for DM.

Polymyositis and dermatomyositis biomarkers

Polymyositis (PM) and dermatomyositis (DM) are the two subtypes of idiopathic inflammatory myositis and are characterized as symmetrical progressive muscle weakness in the proximal extremities. PM/DM affect multiple organs and systems, including the cardiovascular, respiratory and digestive tract systems. An in-depth understanding of PM/DM biomarkers will facilitate development of simple and accurate strategies for diagnosis, treatment, and prognosis prediction. This review summarized the classic biomarkers of PM/DM, including anti-aminoacyl tRNA synthetases (ARS) antibody, anti-Mi-2 antibody, anti-melanoma differentiation-associated gene 5 (MDA5) antibody, anti-transcription intermediary factor 1-γ (TIF1-γ) antibody, anti-nuclear matrix protein 2 (NXP2) antibody, among others. Among them, anti-aminoacyl tRNA synthetases antibody is the most classic. In addition, many potential novel biomarkers were also discussed in this review, including anti-HSC70 antibody, YKL-40, interferons, myxovirus resistance protein 2, regenerating islet-derived protein 3-α, interleukin (IL)-17, IL-35, microRNA (miR)-1 and so on. Among the biomarkers of PM/DM described in this review, classic biomarkers have become the mainstream biomarkers to assist clinicians in diagnosis due to their early discovery, in-depth research, and widespread application. The novel biomarkers also have potential and broad research prospects, which will make immeasurable contributions to exploring biomarker-based classification standards and expanding their application value.

Interleukin-35 in autoimmune dermatoses: Current concepts

Interleukin-35 (IL-35) is a lately observed cytokine and is part of the IL-12 cytokine family. IL-35 includes two subunits, p35 and Epstein-Barr virus-induced gene 3, and activates subsequent signaling pathways by binding to receptors to mediate signal transduction, thereby modulating the immunoregulatory functions of T cells, B cells, macrophages, and other immune cell types. Although there is currently limited research on the roles of IL-35 in human autoimmunity, many studies have demonstrated that IL-35 may mediate immunosuppression. Therefore, it plays an essential role in some autoimmune dermatoses, including systemic lupus erythematosus, psoriasis, systemic sclerosis, and dermatomyositis. We will introduce the structure and biological characteristics of IL-35 and summarize its effects on the occurrence and development of autoimmune dermatoses in this article. It is suggested that IL-35 is a possible target for therapy in the aforementioned diseases.

Interleukin-35 regulates the balance of Th17 and Treg responses during the pathogenesis of connective tissue diseases

Interleukin (IL)-35 belongs to the IL-12 cytokine family and is a heterodimer of the p35 and Epstein-Barr virus-induced gene 3 (EBI3) subunits. Functionally, IL-35 can promote the proliferation and activation of regulatory T cells (Tregs) and suppress the function of T helper 17 (Th17) cells and other inflammatory cells to inhibit immune responses. In recent years, an abnormal IL-35 expression causing a Th17/Treg imbalance has been associated with the development and progression of several connective tissue diseases (CTDs), such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis (DM)/polymyositis (PM), and primary Sjögren's syndrome (pSS). Here, we review the role of IL-35 in regulating the balance of Th17/Treg responses in different types of CTDs and provide new insights into the role of IL-35 in these diseases.