Background: The coronavirus disease 2019 (COVID-19) outbreak, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been declared a global pandemic. It is well-established that SARS-CoV-2 infection can lead to dysregulated immune responses. Arginase-1 (Arg1), which has a pivotal role in immune cells, can be expressed in most of the myeloid cells, e.g., neutrophils and macrophages. Arg1 has been associated with the suppression of antiviral immune responses. Methods: Whole blood was taken from 21 COVID-19 patients and 21 healthy individuals, and after RNA extraction and complementary DNA (cDNA) synthesis, gene expression of Arg1 was measured by real-time PCR. Results: The qPCR results showed that the expression of Arg1 was significantly increased in COVID-19 patients compared to healthy individuals (p < 0.01). The relative expression analysis demonstrated there were approximately 2.3 times increased Arg1 expression in the whole blood of COVID-19 patients. Furthermore, the receiver operating characteristic (ROC) analysis showed a considerable diagnostic value for Arg1 expression in COVID-19 (p = 0.0002 and AUC = 0.8401). Conclusion: Arg1 might be a promising marker in the pathogenesis of the disease, and it could be a valuable diagnostic tool.

Interleukin-10 (IL-10), produced generally by monocyte, T helper type 2 (Th2), and regulatory T cells (Treg), plays a central role in controlling inflammatory responses and regulating the immune response of the IL-10 mRNA expression. It is significantly down-regulated in many autoimmune diseases such as Behçet's disease; this is mostly associated with more aggressive complications. Nevertheless, the essential molecular process for its low expression has not been completely realized. The aim of this project was attempted to estimate the gene expression, promoter methylation, and protein levels to IL-10's down-regulated expression. In this study, blood samples from 51 (4 missed) patients and 63 (2 missed) healthy controls were taken, with the mononuclear cells isolated by the Ficoll Protocol. DNA and RNA were then subsequently extracted. Promoter methylation levels were evaluated by MeDIP-qPCR. Following this, the extracted RNA was converted to cDNA using the RT-PCR method, with the expression of IL-10 later evaluated by Real-time PCR. And then, serum levels of IL-10 were measured using ELISA method. As we expected, the expression level of the IL-10 gene was seen to significantly decline in the patient group in comparison to the control. Also, the rate of promoter methylation was significantly higher in the IL-10 mRNA low expression group (patient group) compared to its high expression group (healthy group) (P < 0.001). We revealed that hypermethylation of promoter region was the principal defect for the IL-10 mRNA low expression in patients with Behçet's disease.

MicroRNAs (miRNAs) are uniquely regulated in healthy, inflamed, activated, cancerous, or other cells and tissues of a pathological state. Many studies confirm that immune dysregulation and autoimmune diseases with inflammation are correlated with various miRNA expression changes in targeted tissues and cells in innate or adaptive immunity. In this review, we will explain the history and classification of epigenetic changes. Next, we will describe the role of miRNAs changes, especially mir-326 in autoimmunity, autoinflammatory, and other pathological conditions. A systematic search of MEDLINE, Embase, and Cochrane Library was presented for all related studies from 1899 to 2017 with restrictions in the English language. In recent years, researchers have concentrated on mostly those roles of miRNA that are correlated with the inflammatory and anti-inflammatory process. Latest studies have proposed a fundamental pathogenic role in cancers and autoinflammatory diseases. Studies have described the role of microRNAs in autoimmunity and autoinflammatory diseases, cancers, and so on. The miRNA-326 expression plays a significant role in autoimmune and other types of diseases.

MicroRNAs (miRNAs) are endogenous mediators of RNA interference and have key roles in the modulation of gene expression under healthy, inflamed, stimulated, carcinogenic, or other cells, and tissues of a pathological state. Many studies have proved the association between miRNAs and cancer. The role of miR-326 as a tumor suppressor miRNA in much human cancer confirmed. We will explain the history and the role of miRNAs changes, especially miR-326 in cancers and other pathological conditions. Attuned with these facts, this review highlights recent preclinical and clinical research performed on miRNAs as novel promising diagnostic biomarkers of patients at early stages, prediction of prognosis, and monitoring of the patients in response to treatment. All related publications retrieved from the PubMed database, with keywords such as epigenetic, miRNA, microRNA, miR-326, cancer, diagnostic biomarker, and therapeutic target similar terms from 1899 to 2018 with limitations in the English language. Recently, researchers have focused on the impacts of miRNAs and their association in inflammatory, autoinflammatory, and cancerous conditions. Recent studies have suggested a major pathogenic role in cancers and autoinflammatory diseases. Investigations have explained the role of miRNAs in cancers, autoimmunity, and autoinflammatory diseases, and so on. The miRNA-326 expression has an important role in cancer conditions and other diseases. K E Y W O R D S cancer, diagnostic biomarker, epigenetic, miR-326, miRNAs, therapeutic target.