Real-Time PCR of cytomegalovirus and Epstein-Barr virus in adult Egyptian patients with systemic lupus erythematosus

Epstein-Barr Virus in Salivary Samples from Systemic Lupus Erythematosus Patients with Oral Lesions

In order to investigate the possible role of Epstein-Barr virus (EBV) in systemic lupus erythematosus (SLE) and its associated oral lesions, a pilot case-control study was performed. A total of 31 patients (18 females and 13 males) were enrolled in the study and divided into two groups: group A included 16 patients with diagnosis of SLE and group B included 15 healthy individuals. Salivary swab samples were collected and subjected to molecular screening by real-time quantitative PCR (qPCR) for the detection of EBV DNA. EBV DNA was significantly detected in 8/16 (50%) SLE patients and in 5/7 (71.4%) subjects with SLE-associated oral lesions. Since EBV is one of the most common viruses in the human population, it is difficult to understand if it is the causative agent of SLE or, vice versa, if SLE is able to trigger the reactivation of EBV. This study highlights a significant association between the presence of EBV and both SLE and SLE-related oral lesions and provides rationale for further investigation into the role of EBV in SLE pathogenesis.

Current mechanistic insights into the role of infection in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by inflammation and abnormal production of autoantibody, but the mechanisms of the aberrant immune responses are currently unknown. Recently, growing evidence has suggested that infection plays a pivotal role in SLE. Here, we investigate the role of infectious agents (e.g., Epstein-Barr virus, parvovirus B19, human T-lymphotropic virus type 1, human immunodeficiency virus type 1, and endogenous retroviruses) in the pathogenesis of SLE. More importantly, we explore the known mechanisms underlying the involvement of infectious agents in the pathogenesis of SLE, including molecular mimicry, epitope spreading, superantigen production, bystander activation, persistent viral infection, altered apoptosis, clearance deficiency, and epigenetic alterations (e.g., DNA methylation and microRNAs). However, some infectious agents (e.g., malaria parasites, hepatitis B virus, Toxoplasma gondii, and Helicobacter pylori) may exert protective effects on SLE. Therefore, the relationship between infection and SLE is multifaceted and multidirectional, including causative and/or protective associations, which warrant further investigation in the future.

Immune responses to an early lytic cytomegalovirus antigen in systemic lupus erythematosus patients: T-cell responses, cytokine secretions and antibody status

We investigated immune responses to a lytic cytomegalovirus antigen (CMVpp52), and to a lytic human herpes virus (HHV) 6 antigen (HHV6p41), in systemic lupus erythematosus (SLE) patients and healthy controls (HCs), in order to clarify if the previously established impaired responses to Epstein-Barr virus (EBV) in SLE patients is a general defect in their responses against (all) HHVs. Multiplex Luminex technology results showed a normal induction of five quantified cytokines (interferon γ, interleukin(IL)12, IL17, IL10, and tumor necrosis factor α) in SLE patients compared to HCs upon stimulation with CMVpp52 and HHV6p41. However, flow cytometric results showed a reduced upregulation of the activation marker CD69 on T-cells from SLE patients (n = 17) compared to HCs (n = 17) upon stimulation with CMVpp52, indicating limited or defective CMVpp52-specific T-cells and/or poor antigen-presentation in SLE patients, and thereby possibly decreased control of the CMV infection. In conclusion, the dysfunctional immune response against EBV previously established in SLE patients does not seem to apply to the same degree regarding the immune responses against CMV or HHV6. Results designate that the main contributing HHV agent in development or exacerbation of SLE (in genetically predisposed individuals) is the previously determined uncontrolled EBV infection, and to a lesser extent CMV infection, and probably with no involvement of HHV6 infection.

How compelling are the data for Epstein-Barr virus being a trigger for systemic lupus and other autoimmune diseases?

PURPOSE OF REVIEW

Systemic lupus erythematosus (SLE) is caused by a combination of genetic and acquired immunodeficiencies and environmental factors including infections. An association with Epstein-Barr virus (EBV) has been established by numerous studies over the past decades. Here, we review recent experimental studies on EBV, and present our integrated theory of SLE development.

RECENT FINDINGS

SLE patients have dysfunctional control of EBV infection resulting in frequent reactivations and disease progression. These comprise impaired functions of EBV-specific T-cells with an inverse correlation to disease activity and elevated serum levels of antibodies against lytic cycle EBV antigens. The presence of EBV proteins in renal tissue from SLE patients with nephritis suggests direct involvement of EBV in SLE development. As expected for patients with immunodeficiencies, studies reveal that SLE patients show dysfunctional responses to other viruses as well. An association with EBV infection has also been demonstrated for other autoimmune diseases, including Sjögren's syndrome, rheumatoid arthritis, and multiple sclerosis.

SUMMARY

Collectively, the interplay between an impaired immune system and the cumulative effects of EBV and other viruses results in frequent reactivation of EBV and enhanced cell death, causing development of SLE and concomitant autoreactivities.

Infection in systemic lupus erythematosus, similarities, and differences with lupus flare

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with diverse manifestations, and its pathogenesis is unclear and complicated. Infection and SLE are similar in that they both cause inf lammatory reactions in the immune system; however, one functions to protect the body, whereas the other is activated to damage the body. Infection is known as one of the common trigger factors for SLE; there are a number of reports on infectious agents that provoke autoimmune response. Several viruses, bacteria, and protozoa were revealed to cause immune dysfunction by molecular mimicry, epitope spreading, and bystander activation. In contrast, certain pathogens were revealed to protect from immune dysregulation. Infection can be threatening to patients with SLE who have a compromised immune system, and it is regarded as one of the common causes of mortality in SLE. A clinical distinction between infection and lupus f lare up is required when patients with SLE present fevers. With a close-up assessment of symptoms and physical examination, C-reactive protein and disease activity markers play a major role in differentiating the different disease conditions. Vaccination is necessary because protection against infection is important in patients with SLE.

Correlation between Epstein-Barr Virus Infection and Disease Activity of Systemic Lupus Erythematosus: a Cross-Sectional Study

Background:

Systemic lupus erythematosus (SLE) is an autoimmune disease for whose pathogenesis viral infections are important. The Epstein-Barr virus (EBV) is the main infectious etiological agent. This study aimed to quantitative evaluation of EBV in SLE patients.

Materials and Methods:

In this cross-sectional study, 40 patients with SLE diagnosed based on American College of Rheumatology criteria were selected using purposive sampling. All were included in the study after obtaining informed consent for participation. Whole blood samples were taken and buffy coat preparations were isolated to determine viral load using the real-time polymerase chain reaction method and assessment with the SLE disease activity index (SLE-DAI).

Results:

From a total of 40 patients, 37 cases (92.5%) were women. The EBV test was positive in 67.5% and mean viral load was 5396 ± 1891.9 copy/ml. Twenty of forty patients had active and 50% inactive disease, mean EBV viral loads being 6798 and 28.25 copy/ml, respectively (P-value = 0.003). In terms of the severity of disease activity, 17.5 % of female patients had mild to moderate activity, whilst 32.5% of them had severe activity, with respective viral loads of 5,803.3 and 29.73 copy/ml (P-value = 0.003).

Conclusion:

The Epstein-Barr viral load in SLE patients with active disease was found to be markedly higher than in inactive cases. Thus, EBV may have an important role in the pathogenesis and activity of SLE.

The Folate Cycle As a Cause of Natural Killer Cell Dysfunction and Viral Etiology in Type 1 Diabetes

The folate pathway is critical to proper cellular function and metabolism. It is responsible for multiple functions, including energy (ATP) production, methylation reactions for DNA and protein synthesis and the production of immunomodulatory molecules, inosine and adenosine. These play an important role in immune signaling and cytotoxicity. Herein, we hypothesize that defects in the folate pathway in genetically susceptible individuals could lead to immune dysfunction, permissive environments for chronic cyclical latent/lytic viral infection, and, ultimately, the development of unchecked autoimmune responses to infected tissue, in this case islet beta cells. In the context of type 1 diabetes (T1D), there has been a recent increase in newly diagnosed cases of T1D in the past 20 years that has exceeded previous epidemiological predictions with yet unidentified factor(s). This speaks to a potential environmental trigger that adversely affects immune responses. Most research into the immune dysfunction of T1D has focused on downstream adaptive responses of T and B cells neglecting the role of the upstream innate players such as natural killer (NK) cells. Constantly, surveilling the blood and tissues for pathogens, NK cells remove threats through direct cytotoxic responses and recruitment of adaptive responses using cytokines, such as IL-1β and IFN-γ. One long-standing hypothesis suggests viral infection as a potential trigger for the autoimmune response in T1D. Recent data suggest multiple viruses as potential causal agents. Intertwined with this is an observed reduced NK cell enumeration, cytotoxicity, and cytokine signaling in T1D patients. Many of the viruses implicated in T1D are chronic latent/lysogenic infections with demonstrated capacity to reduce NK cell response and number through mechanisms that resemble those of pregnancy tolerance. Defects in the folate pathway in T1D patients could result in decreased immune response to viral infection or viral reactivation. Dampened NK responses to infections result in improper signaling, improper antigen presentation, and amplified CD8⁺ lymphocyte proliferation and cytotoxicity, a hallmark of beta cell infiltrates in patients with T1D onset. This would suggest a critical role for NK cells in T1D development linked to viral infection and the importance of the folate pathway in maintaining proper NK response.

Infection and Lupus: Which Causes Which?

Infection is a leading cause of morbidity and mortality among patients with systemic lupus erythematous (SLE). Dysfunction of the innate and adaptive immune systems increases the risk of infection in patients with SLE. Infectious agents have also been theorized to play a role in the pathogenesis of SLE. This article summarizes our current knowledge of the infectious risk SLE patients face as a result of their underlying disease including abnormal phagocytes and T cells as well as the increased risk of infection associated with immunosuppressive agents used to treat disease. Pathogens thought to play a role in the pathogenesis of disease including EBV, CMV, human endogenous retroviruses (HERVs), and tuberculosis will also be reviewed, as well as the pathologic potential of microbial amyloids and the microbiome.