Potential role of EBV and Toll-like receptor 9 ligand in patients with systemic lupus erythematosus.

SLE is a multisystem autoimmune disease characterized by multiple immunological abnormalities including production of autoantibodies. While the etiology of SLE is largely unknown, it is generally accepted that both genetic and environmental factors contribute to disease risk and immune dysregulation. Production of IFN-α is important for protecting the host against infections; however, over stimulation of innate immune pathways can induce autoimmune disease. Environmental factors, particularly Epstein-Barr virus (EBV), have been proposed to play an important role in SLE disease. Improper engagement of Toll-like receptor (TLR) pathways by endogenous or exogenous ligands may lead to the initiation of autoimmune responses and tissue injury. EBV is shown to be a potent stimulant of IFN-α by TLR signaling cascades. Given the highlighted role of IFN-α in SLE pathogenesis and potential role of EBV infection in this disease, the present study is aimed at exploring the in vitro effects of EBV infection and CPG (either alone or in combination) on IFN-α. We also examined the expression level of CD20 and BDCA-4 and CD123 in PBMCs in 32 SLE patients and 32 healthy controls. Our results showed PBMCs treated with CPG-induced higher levels of IFN-α and TLR-9 gene expression fold change compared to cells treated with either EBV or EBV-CPG. Moreover, PBMCs treated with CPG produced significantly higher IFN-α concentration in supernatant compared to cells treated with EBV but not EBV-CPG. Our results further highlight the potential role of EBV infection and TLRs in SLE patients although more studies are warranted to ascertain the global imprint that EBV infection can have on immune signature in patients with SLE.

Overall Status of Epstein-Barr virus Infection, IFN-a, and TLR-7/9 in Patients with Systemic Lupus Erythematous.

BACKGROUND: Systemic lupus erythematous (SLE) is a multisystem autoimmune disorder. While studying the pathogenesis of SLE is prevalent, both infectious and non-infectious elements are regarded to exert an important impact on the disease's development. OBJECTIVE: To explore the overall status of EBV, TLR7, TLR9, and IFN-α gene expression in 32 patients suffering from SLE and 32 healthy controls. METHODS: Plasma and PBMCs were separated from fresh whole blood. To measure EBV DNA load and mRNA levels of IFN-a, TLR-7 and9 in PBMCs, molecular techniques were employed. The production of IFN-α, ds-DNA IgG antibody, and EBNA-1 IgG levels were also measured in plasma by ELISA. RESULTS: SLE patients showed significantly higher EBV load (p=0.001) and transcriptional levels of TLR7 (p=0.0001), IFN-α (p=0.0001), and TLR9 (p=0.0001) than controls. Moreover, the plasma levels of IFN-α (p=0.0002) and EBNA-1specific IgG antibodies (p=0.01) were significantly higher in SLE patients. CONCLUSION: The results stressed on the potential role of EBV infection and TLRs in SLE patients although more research is needed to determine the global impact that EBV infection can have on immune signature in patients with SLE.

Potential role of viral infection and B cells as a linker between innate and adaptive immune response in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves several organ systems. Although B cells play a key role in SLE pathogenesis, the mechanisms behind B cell dysregulation in SLE development remained controversial. Finding the modules containing highly co-expressed genes in B cells could explain biological pathways involved in the pathogenesis of SLE, which may further support the reasons for the altered function of B cells in SLE disease. A total of three microarray gene expression datasets were downloaded from Gene Expression Omnibus. SLE samples were prepared from the purified B lymphocyte cells of the patients who have not received immunosuppressive drugs as well as high dose immunocytotoxic therapies or steroids. A weighted gene co-expression network was then constructed to find the relevant modules implicated in the SLE progression. Among 17 identified modules, 3 modules were selected through mapping to STRING and finding the ones that had highly connection at the protein level. These modules clearly indicate the involvement of several pathways in the pathogenesis of SLE including viral infection, adaptive immune response, and innate immune response in B lymphocytes. The WGCN analysis further revealed the co-expressed genes involved in both innate and adaptive immune systems. Mix infections and primary immunodeficiency might also dysregulate B lymphocytes, which may facilitate SLE development. As such, identifying novel biomarkers and pathways in lupus would be of importance.