CXCL10 and CCL2 chemokine serum levels in patients with hepatitis C associated with autoimmune thyroiditis

Evaluating the role of chemokines and chemokine receptors involved in coronavirus infection

INTRODUCTION

Coronaviruses are a large family of positive-stranded nonsegmented RNA viruses with genomes of 26-32 kilobases in length. Human coronaviruses are commonly associated with mild respiratory illness; however, the past three decades have seen the emergence of severe acute respiratory coronavirus (SARS-CoV), middle eastern respiratory coronavirus (MERS-CoV), and SARS-CoV-2 which is the etiologic agent for COVID-19. Severe forms of COVID-19 include acute respiratory distress syndrome (ARDS) associated with cytokine release syndrome that can culminate in multiorgan failure and death. Among the proinflammatory factors associated with severe COVID-19 are the chemokines CCL2, CCL3, CXCL8, and CXCL10. Infection of susceptible mice with murine coronaviruses, such as mouse hepatitis virus (MHV), elicits a similar chemokine response profile as observed in COVID-19 patients and these in vivo models have been informative and show that targeting chemokines reduces the severity of inflammation in target organs.

AREAS COVERED

PubMed was used using keywords: Chemokines and coronaviruses; Chemokines and mouse hepatitis virus; Chemokines and COVID-19. Clinicaltrials.gov was used using keywords: COVID-19 and chemokines; COVID-19 and cytokines; COVID-19 and neutrophil.

EXPERT OPINION

Chemokines and chemokine receptors are clinically relevant therapeutic targets for reducing coronavirus-induced inflammation.

Th1 Chemokines in Autoimmune Endocrine Disorders

CONTEXT

The CXC chemokine receptor CXCR3 and its chemokines CXCL10, CXCL9, and CXCL11 are implicated in the pathogenesis of autoimmune diseases. Here, we review these chemokines in autoimmune thyroiditis (AT), Graves disease (GD), thyroid eye disease (TED), type 1 diabetes (T1D), and Addison's disease (AAD).

EVIDENCE ACQUISITION

A PubMed review of the literature was conducted, searching for the above-mentioned chemokines in combination with AT, GD, TED, T1D, and AAD.

EVIDENCE SYNTHESIS

Thyroid follicular cells in AT and GD, retroorbital cells in TED (fibroblasts, preadipocytes, myoblasts), β cells and islets in T1D, and adrenal cells in AAD respond to interferon-γ (IFN-γ) stimulation producing large amounts of these chemokines. Furthermore, lymphocytes and peripheral blood mononuclear cells (PBMC) are in part responsible for the secreted Th1 chemokines. In AT, GD, TED, T1D, and AAD, the circulating levels of these chemokines have been shown to be high. Furthermore, these chemokines have been associated with the early phases of the autoimmune response in all the above-mentioned disorders. High levels of these chemokines have been associated also with the "active phase" of the disease in GD, and also in TED. Other studies have shown an association with the severity of hypothyroidism in AD, of hyperthyroidism in GD, with severity of TED, or with fulminant T1D.

CONCLUSION

The reviewed data have shown the importance of the Th1 immune response in different endocrine autoimmune diseases, and many studies have suggested that CXCR3 and its chemokines might be considered as potential targets of new drugs for the treatment of these disorders.

Graves' disease: Epidemiology, genetic and environmental risk factors and viruses

Graves' disease (GD) is the most common cause of hyperthyroidism in developed Countries. It is more common between 30 and 60 years; 5-10 times more frequent in women. The genetic predisposition accounts for 79% of the risk for GD, while environmental factors for 21%. About 70% of genes associated with autoimmune thyroid disorders (AITD) are implicated in T-cell function. Among GD endogenous factors, estrogens, X-inactivation and microchimerism are important. Among environmental risk factors, smoking, iodine excess, selenium and vitamin D deficiency, and the occupational exposure to Agent Orange have been associated with GD. Many studies showed that HCV is associated with thyroid autoimmunity and hypothyroidism, in patients with chronic HCV hepatitis (CHC); a significant link has been shown also between HCV-related mixed cryoglobulinemia and risk for GD. Moreover, IFN-α-treated CHC patients develop GD more frequently. Novel studies are needed about possible risk factors to reduce the occurence of GD in West Countries.

Monocyte chemoattractant protein 1 released from macrophages induced by hepatitis C virus promotes monocytes migration

Hepatitis C Virus (HCV) infection usually progress to chronic liver disease and shows a significant increase in total monocyte/macrophages numbers in the liver. Monocyte chemoattractant protein-1 (MCP-1) plays a role in the recruitment of monocytes to the liver. In this study we found that MCP-1 were up-regulated in macrophages cultured with cell-culture derived infectious HCV particles (HCVcc) and promoted the migration of monocytes. IL1β, IL6 and TNFα were factors that induced MCP-1 expression, which were up-regulated in macrophages induced by HCV. Long-term of HCV incubation induced apoptosis of macrophages. Finally, we observed the effect of HCV infected macrophages on nearby liver cells. Huh7 cells continuously co-cultured with monocyte/macrophages displayed increased expression of pro-inflammatory cytokines and the morphology of Huh7 cells were greatly changed. Taken together, our study provides more information for the role of monocyte/macrophages in HCV related chronic liver disease.

Hepatitis C virus-associated pruritus: Etiopathogenesis and therapeutic strategies

In addition to its contributing role in the development of chronic liver diseases, chronic hepatitis C virus (HCV) infection is associated with extrahepatic manifestations, particularly, cutaneous-based disorders including those with pruritus as a symptom. Pruritus is frequently associated with the development of chronic liver diseases such as cholestasis and chronic viral infection, and the accumulation of bile acids in patients’ sera and tissues as a consequence of liver damage is considered the main cause of pruritus. In addition to their role in dietary lipid absorption, bile acids can trigger the activation of specific receptors, such as the G protein-coupled bile acid receptor (GPBA/ TGR5). These types of receptors are known to play a crucial role in the modulation of the systemic actions of bile acids. TGR5 expression in primary sensory neurons triggers the activation of the transient receptor potential vanilloid 1 (TRPV1) leading to the induction of pruritus by an unknown mechanism. Although the pathologic phenomenon of pruritus is common, there is no uniformly effective therapy available. Understanding the mechanisms regulating the occurrence of pruritus together with the conduction of large-scale clinical and evidence-based studies, may help to create a standard treatment protocol. This review focuses on the etiopathogenesis and treatment strategies of pruritus associated with chronic HCV infection.

Cytokines and HCV-related autoimmune disorders

Cytokines are intercellular mediators involved in viral control and liver damage being induced by infection with hepatitis C virus (HCV). The complex cytokine network operating during initial infection allows a coordinated, effective development of both innate and adaptive immune responses. However, HCV interferes with cytokines at various levels and escapes immune response by inducing a T-helper (Th)2/T cytotoxic 2 cytokine profile. Inability to control infection leads to the recruitment of inflammatory infiltrates into the liver parenchyma by interferon (IFN)-γ-inducible CXC chemokine ligand (CXCL)9, -10, and -11 chemokines, which results in sustained liver damage and eventually in liver cirrhosis. The most important systemic HCV-related extrahepatic diseases-mixed cryoglobulinemia, lymphoproliferative disorders, thyroid autoimmune disorders, and type 2 diabetes-are associated with a complex dysregulation of the cytokine/chemokine network, involving proinflammatory and Th1 chemokines. The therapeutical administration of cytokines such as IFN-α may result in viral clearance during persistent infection and revert this process. Theoretically agents that selectively neutralize CXCL10 could increase patient responsiveness to traditional IFN-based HCV therapy. Several studies have reported IL-28B polymorphisms and circulating CXCL10 may be a prognostic markers for HCV treatment efficacy in HCV genotype 1 infection.

Chemokine (C-X-C motif) ligand (CXCL)10 in autoimmune diseases

(C-X-C motif) ligand (CXCL)10 (CXCL10) belongs to the ELR(-) CXC subfamily chemokine. CXCL10 exerts its function through binding to chemokine (C-X-C motif) receptor 3 (CXCR3), a seven trans-membrane receptor coupled to G proteins. CXCL10 and its receptor, CXCR3, appear to contribute to the pathogenesis of many autoimmune diseases, organ specific (such as type 1 diabetes, autoimmune thyroiditis, Graves' disease and ophthalmopathy), or systemic (such as rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, mixed cryoglobulinemia, Sjögren syndrome, or systemic sclerosis). The secretion of CXCL10 by cluster of differentiation (CD)4+, CD8+, natural killer (NK) and NK-T cells is dependent on interferon (IFN)-γ, which is itself mediated by the interleukin-12 cytokine family. Under the influence of IFN-γ, CXCL10 is secreted by several cell types including endothelial cells, fibroblasts, keratinocytes, thyrocytes, preadipocytes, etc. Determination of high level of CXCL10 in peripheral fluids is therefore a marker of host immune response, especially T helper (Th)1 orientated T-cells. In tissues, recruited Th1 lymphocytes may be responsible for enhanced IFN-γ and tumor necrosis factor-α production, which in turn stimulates CXCL10 secretion from a variety of cells, therefore creating an amplification feedback loop, and perpetuating the autoimmune process. Further studies are needed to investigate interactions between chemokines and cytokines in the pathogenesis of autoimmune diseases and to evaluate whether CXCL10 is a novel therapeutic target in various autoimmune diseases.

Increased CXCL9 serum levels in hepatitis C-related mixed cryoglobulinemia, with autoimmune thyroiditis, associated with high levels of CXCL10

Until now, no study has evaluated CXCL9 in hepatitis C virus (HCV) infection-related mixed cryoglobulinemia (MC) patients in presence/absence of autoimmune thyroiditis (AT). Serum CXCL9 and CXCL10 have been measured in 60 patients with MC (MCo), in 35 patients with MC and AT (MC-AT), in sex and age-matched controls: 60 healthy (Control 1); 35 patients with AT without cryoglobulinemia (Control 2). CXCL9 and CXCL10 were higher in MC-AT patients than Control 2 (P<0.0001) and MCo (P=0.01), in MCo than Control 1 (P<0.0001), and in Control 2 than Control 1 (P<0.001). By defining a high CXCL9 level as a value>2 SD above the mean value of the Control 1 (>122 pg/mL), 5% of Control 1, 34% of Control 2, 91% of MCo, and 97% of MC+AT had high CXCL9 (P<0.0001, chi-square). By simple regression analysis CXCL9 and CXCL10 were related to each other in MCo (r=0.426, P=0.001) and in MC-AT (r=0.375, P=0.001). We first demonstrate high serum levels of CXCL9 in cryoglobulinemic patients, especially with AT. Further, a strong association between serum CXCL9 and CXCL10 has been observed in patients with MC in presence/absence of AT.

Chemokine (C-C motif) ligand 2 (CCL2) in sera of patients with type 1 diabetes and diabetic complications

Background

Chemokine (C-C motif) ligand 2 (CCL2), commonly known as monocyte chemoattractant protein-1 (MCP-1), has been implicated in the pathogenesis of many diseases characterized by monocytic infiltration. However, limited data have been reported on MCP-1 in type 1 diabetes (T1D) and the findings are inconclusive and inconsistent.

Methods

In this study, MCP-1 was measured in the sera from 2,472 T1D patients and 2,654 healthy controls using a Luminex assay. The rs1024611 SNP in the promoter region of MCP-1 was genotyped for a subset of subjects (1764 T1D patients and 1323 controls) using the TaqMan-assay.

Results

Subject age, sex or genotypes of MCP-1 rs1024611SNP did not have a major impact on serum MCP-1 levels in either healthy controls or patients. While hemoglobin A1c levels did not have a major influence on serum MCP-1 levels, the mean serum MCP-1 levels are significantly higher in patients with multiple complications (mean = 242 ng/ml) compared to patients without any complications (mean = 201 ng/ml) (p = 3.5×10⁻⁶). Furthermore, mean serum MCP-1 is higher in controls (mean = 261 ng/ml) than T1D patients (mean = 208 ng/ml) (p<10⁻²³). More importantly, the frequency of subjects with extremely high levels (>99^th percentile of patients or 955 ng/ml) of serum MCP-1 is significantly lower in the T1D group compared to the control group (odds ratio = 0.11, p<10⁻³³).

Conclusion

MCP-1 may have a dual role in T1D and its complications. While very high levels of serum MCP-1 may be protective against the development of T1D, complications are associated with higher serum MCP-1 levels within the T1D group.