Exploring the role of tryptophanyl-tRNA synthetase and associations with inflammatory markers and clinical outcomes in COVID-19 patients: A case-control study.

Tryptophanyl-tRNA synthetase (WRS) is a critical enzyme involved in protein synthesis, responsible for charging tRNA with the essential amino acid tryptophan. Recent studies have highlighted its novel role in stimulating innate immunity against bacterial and viral infections. However, the significance of WRS in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains elusive. In this study, we aimed to investigate the complex interplay between WRS, inflammatory markers, Toll-like receptor-4 (TLR-4), and clinical outcomes in coronavirus disease 19 (COVID-19) patients. A case-control investigation comprised 127 COVID-19 patients, carefully classified as severe or moderate upon admission, and 112 healthy individuals as a comparative group. Blood samples were meticulously collected before treatment initiation, and WRS, interleukin-6 (IL-6), and C-reactive protein (CRP) concentrations were quantified using a well-established commercial ELISA kit. Peripheral blood mononuclear cells (PBMCs) were isolated from the blood samples, and RNA was extracted for cDNA synthesis. Semi-quantitative real-time polymerase chain reaction (PCR) was employed to assess the relative expression of TLR-4. COVID-19 patients exhibited elevated levels of WRS, IL-6, CRP, and TLR-4 expression compared to healthy individuals, with the severe group displaying significantly higher levels than the moderate group. Notably, severe patients demonstrated substantial fluctuations in CRP, IL-6, and WRS levels over time, a pattern not observed in their moderate counterparts. Although no significant distinctions were observed in the dynamic alterations of WRS, IL-6, CRP, and TLR-4 expression between deceased and surviving patients, a trend emerged indicating higher IL-6_1 levels in deceased patients and elevated lactate dehydrogenase (LDH) levels in severe patients who succumbed to the disease. This pioneering research highlights the dynamic alterations of WRS in COVID-19 patients, providing valuable insights into the correlation between WRS, inflammatory markers, and disease severity within this population. Understanding the role of WRS in SARS-CoV-2 infection may open new avenues for therapeutic interventions targeting innate immunity to combat COVID-19.

The role of lovastatin in the attenuation of COVID-19.

The mounting evidence regarding the pathogenesis of COVID-19 indicated that the cytokine storm has an axial role in the severity of this disease, which may lead to thrombotic complications, acute respiratory distress syndrome (ARDS), and myocardial damage, among other consequences. It has recently been demonstrated that statins are known to have anti-viral, anti-inflammatory, anti-thrombotic, and immunomodulatory features; however, their advantage has not been evaluated in COVID-19. This study aimed to investigate the protective effects of lovastatin in intensive care unit (ICU) patients with COVID-19. The case-control study consists of 284 ICU patients, which classified into three groups as follows: 1) the patients who no received lovastatin as a control (92 patients), 2) patients received 20 mg per day lovastatin (99 patients), and 3) patients received 40 mg per day lovastatin (93 patients). Each group's demographic and clinical parameters, along with CRP, interleukin (IL)-6, IL-8 levels, and mortality rate, were studied in three-time points. The results showed that there was no statistically significant difference between our study groups in terms of age and sex. (P > 0.05). Besides, in patients, receiving lovastatin the CRP, IL-6, IL-8 levels were significantly decreased from T1 to T3 than to the control group. Our results also showed that the use of lovastatin in COVID-19 patients significantly reduced the length of hospitalization in the ICU compared with the control group. In addition, our results showed that the mortality rate in patients receiving lovastatin was lower when compared to the control group; however, this difference was not statistically significant. Since the cytokine storm is a significant factor in the pathology of SARS-CoV-2, our findings highlighted the potential use of lovastatin to mitigate the inflammatory response induced by SARS-CoV-2 infection.

A possible pathogenic correlation between neutrophil elastase (NE) enzyme and inflammation in the pathogenesis of coronavirus disease 2019 (COVID-19).

A growing body of evidence indicates that neutrophil elastase (NE) is involved in the pathogenesis of respiratory infectious diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to analyze the dynamic changes in serum levels of NE associated with inflammation, disease activity, and mortality rate in patients with COVID-19. We measured the serum concentrations of NE, C-Reactive protein (CRP), interleukin (IL)- 4, IL-6, IL-8, IL-10, and vitamin D levels in 83 ICU and 69 non-ICU patients compared with 82 healthy subjects (HS) in three-time points (T1-T3). Serum levels of NE, IL-6, IL-8, and CRP in ICU and non-ICU patients were significantly higher than HS (P < 0.001) in three-time points. Also, serum levels of NE, IL-6, IL-8, and CRP in ICU patients were significantly higher than in non-ICU patients (P < 0.05). On the day of admission (T1), the levels of NE, CRP, IL-6, IL-8 were gradually decreased from T1 to T3. At the same time, IL-4 and IL-10 were gradually increased from T1 to T2 and then reduced to T3. Further analyses demonstrated that the levels of NE, IL-6, and IL-8 in deceased patients were significantly higher than in recovered patients (P < 0.05). The ROC curve analysis demonstrated that markers, including NE, IL-6, and IL-8, were valuable indicators in evaluating the activity of COVID-19. Overall, our results signify the critical role of NE in the pathogenesis of COVID-19, and also, further support that NE has a potential therapeutic target for the attenuation of COVID-19 severity.

A possible pathogenic role of Syndecan-1 in the pathogenesis of coronavirus disease 2019 (COVID-19).

A cell-surface heparan proteoglycan called Syndecan-1 (SDC-1) has multiple roles in healthy and pathogenic conditions, including respiratory viral infection. In this study, we explore the dynamic alternation in the levels of SDC-1 in cases with COVID-19. A total of 120 cases definitely diagnosed with COVID-19 were admitted to the Firoozgar Hospital, Tehran, Iran, from December 1, 2020, to January 29, 2021, and included in our study. Also, 58 healthy subjects (HS) were chosen as the control group. Patients were classified into two groups: 1) ICU patients and (63 cases) 2) non-ICU patients (57 cases). The dynamic changes of serum SCD-1, CRP, IL-6, IL-10, IL-18, and Vit D levels a well as the disease activity were investigated in three-time points (T1-T3). Our results indicated that the COVID-19 patients had significantly increased SCD-1, CRP, IL-6, IL-10, and IL-18 levels than in HS, while the Vit D levels in COVID-19 patients were significantly lower than HS. Further analysis demonstrated that the SCD-1, CRP, IL-6, IL-10, and IL-18 levels in ICU patients were significantly higher than in non-ICU patients. Tracking dynamic changes in the above markers indicated that on the day of admission, the SCD-1, CRP, IL-6, IL-10, and IL-18 levels were gradually increased on day 5 (T2) and then gradually decreased on day 10 (T3). ROC curve analysis suggests that markers mentioned above, SDC-1, IL-6, and IL-18 are valuable indicators in evaluating the activity of COVID-19. All in all, it seems that the serum SDC-1 levels alone or combined with other markers might be a good candidate for disease activity monitoring.

The role of human herpesvirus-6 and inflammatory markers in the pathogenesis of multiple sclerosis.

Multiple sclerosis (MS) is a destructive autoimmune neuroinflammatory and neurodegenerative disorder of the central nervous system (CNS) with unknown etiology and mechanism of pathogenesis. Pathogens, especially human herpes viruses, have been suggested as environmental factors of the MS and other neuroinflammatory disorders. This study aimed to determine the prevalence of HHV-6 antibody response in MS patients and investigate the levels of pro/anti-inflammatory cytokine and chemokines in MS patients in comparison with healthy subjects. Two hundred sixty-three patients with clinically defined MS (140 females and 123 males), along with 263 healthy subjects (140 females and 123 males), were recruited for this study. After the analysis of HHV-6 seropositivity/seronegativity, the levels of some pro/anti-inflammatory cytokines, including TNF-α, IFN-γ, IL-1ß, IL-6, and IL-12 as well as two chemokines, namely CCL-2 and CCL-5 were determined by the enzyme-linked immunosorbent assay (ELISA) method in HHV-6 seropositive/seronegative MS patients and healthy subjects. Our results showed that the serum concentrations of TNF-α, IFN-γ, IL-1ß, IL-6, and CCL-5 elevated in HHV-6 seropositive compared with seronegative MS patients (P < .05). Moreover, the levels of IL-12, IL-10, and CCL-2 levels were significantly lower in seropositive MS patients when compared with seronegative MS patients (P < .05). Also, our results revealed that the mean values of the expanded disability status scale (EDSS) were significantly higher in HHV-6 seropositive versus seronegative MS patients (P < .05). In conclusion, we proposed that HHV-6 infection may play a role in MS pathogenesis by changing cytokine signaling in MS patients that may lead to peripheral inflammation.

Serum levels of matrix metalloproteinase-2, -9, and vitamin D in patients with multiple sclerosis with or without herpesvirus-6 seropositivity.

In recent years, extreme attention has been focused on the role of human herpesvirus-6 (HHV-6) in multiple sclerosis (MS) pathogenesis. However, the pathogenesis of MS associated with HHV-6 infection remains unknown. In this study, we measured the serum levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and vitamin D levels in MS patients with HHV-6 infection and MS patients without HHV-6 infection. Five hundred sixty (including 300 females and 260 males) MS patients along with 560 healthy subjects were analyzed for HHV-6 seropositivity using enzyme-linked immunosorbent assay (ELISA). Subsequently, we measured the serum levels of MMP-2, MMP-9, and vitamin D levels in MS patients with HHV-6 infection and MS patients without HHV-6 infection by ELISA. About 90.7% of MS patients (508/560) were seropositive for HHV-6, while 82.3% (461/560) of healthy subjects were seropositive for this virus (p = 0.001). Moreover, there was a significant increase in the levels of MMP-2, MMP-9, and lower vitamin D in the serum samples of MS patients when compared with healthy subjects. Additionally, we demonstrated that the MMP-9 levels in seropositive MS patients were significantly higher than seronegative MS patients (p =  0.001). Finally, our results demonstrated that the mean of expanded disability status scale (EDSS) in seropositive MS patients was significantly higher in comparison to seronegative MS patients (p < 0.05). In conclusion, we suggest that the HHV-6 infection may play a role in MS pathogenesis.

Serum levels of matrix metalloproteinase-2, -9, and vitamin D in patients with multiple sclerosis with or without herpesvirus-6 seropositivity

ABSTRACT In recent years, extreme attention has been focused on the role of human herpesvirus-6 (HHV-6) in multiple sclerosis (MS) pathogenesis. However, the pathogenesis of MS associated with HHV-6 infection remains unknown. In this study, we measured the serum levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and vitamin D levels in MS patients with HHV-6 infection and MS patients without HHV-6 infection. Five hundred sixty (including 300 females and 260 males) MS patients along with 560 healthy subjects were analyzed for HHV-6 seropositivity using enzyme-linked immunosorbent assay (ELISA). Subsequently, we measured the serum levels of MMP-2, MMP-9, and vitamin D levels in MS patients with HHV-6 infection and MS patients without HHV-6 infection by ELISA. About 90.7% of MS patients (508/560) were seropositive for HHV-6, while 82.3% (461/560) of healthy subjects were seropositive for this virus (p = 0.001). Moreover, there was a significant increase in the levels of MMP-2, MMP-9, and lower vitamin D in the serum samples of MS patients when compared with healthy subjects. Additionally, we demonstrated that the MMP-9 levels in seropositive MS patients were significantly higher than seronegative MS patients (p = 0.001). Finally, our results demonstrated that the mean of expanded disability status scale (EDSS) in seropositive MS patients was significantly higher in comparison to seronegative MS patients (p < 0.05). In conclusion, we suggest that the HHV-6 infection may play a role in MS pathogenesis.

Inhibition of protein disulfide isomerase has neuroprotective effects in a mouse model of experimental autoimmune encephalomyelitis.

Endoplasmic reticulum (ER) stress is strictly linked to neuroinflammation and involves in the development of neurodegenerative disorders. Protein disulfide isomerase (PDI) is an enzyme that catalyzes formation and isomerization of disulfide bonds and also acts as a chaperone that survives the cells against cell death by removal of misfolded proteins. Our previous work revealed that PDI is explicitly upregulated in response to myelin oligodendrocyte glycoprotein (MOG)-induced ER stress in the brain of experimental autoimmune encephalomyelitis (EAE) mice. The significance of overexpression of PDI in the apoptosis of neural cells prompted us to study the effect of CCF642, efficient inhibitor of PDI, in the recovery of EAE clinical symptoms. Using this in vivo model, we characterized the ability of CCF642 to decrease the expression of ER stress markers and neuroinflammation in the hippocampus of EAE mice. Our observations suggested that CCF642 administration attenuates EAE clinical symptomsand the expression of ER stress-related proteins. Further, it suppressed the inflammatory infiltration of CD4 + T cells and the activation of hippocampus-resident microglia and Th17 cells. We reported here that the inhibition of PDI protected EAE mice against neuronal apoptosis induced by prolonged ER stress and resulted in neuroprotection.

Maraviroc attenuates the pathogenesis of experimental autoimmune encephalitis.

It has been shown that the blockade of chemokine receptor type 5 can dampen inflammatory reaction within the central nervous system (CNS). In the present study, we utilized maraviroc, a potent antagonist o CCR5, to examine whether this drug can mitigate neuroinflammation in the spinal cord of mice induced by experimental autoimmune encephalitis (EAE), considered a murine model of multiple sclerosis (MS). For this aim, mice were immunized with myelin oligodendrocyte glycoprotein 35-55 (MOG35-55), followed by pertussis toxin to induce paralysis in EAE mice. The animals intraperitoneally received various doses of maraviroc (5, 25, and 50 mg/kg body weight) when the early clinical signs of EAE appeared. The results demonstrated that the administration of maraviroc led to a marked decrease in the clinical score and improvement in behavioral motor functions. Moreover, our finding indicated that the administration of maraviroc significantly attenuates the infiltration of inflammatory cells to the spinal cord, microgliosis, astrogliosis, pro-inflammatory cytokines, and cell death in EAE mice. The flow cytometry data indicated that a decreased number of CD4+ and CD8+ T cells in the peripheral blood of mice with EAE without affecting the number of T regulatory cells (CD4 + CD25+ forkhead box protein 3+). Finally, it seems that maraviroc is well-tolerated, and targeting CCR5 could open up a new horizon in the treatment of MS.

HIV-1 Tat protein attenuates the clinical course of experimental autoimmune encephalomyelitis (EAE).

A growing body of evidence has shown that the human immunodeficiency virus (HIV) infection is associated with a significantly decreased risk of developing multiple sclerosis (MS) in patients with acquired immunodeficiency virus (AIDS). It is thought that two mechanisms are in charge of protection against MS, which include immunosuppression induced by chronic HIV infection (depletion of CD4 + T cells) and antiretroviral medications. HIV-1 encodes several regulatory (Tat and Rev) and accessory (Vpr, Vif, Vpu, and Nef) proteins that have immunosuppressive and immunomodulatory properties. HIV-1 Tat protein is a strongly immunosuppressive agent and can cross the blood-brain barrier (BBB). In this study, we examined the effect of HIV-1 Tat, which is classified into clade B and C, on inflammation, gliosis, apoptosis, and behavioral function in a murine model of MS called experimental autoimmune encephalomyelitis (EAE). For this aim, mice were immunized with myelin oligodendrocyte glycoprotein 35-55 (MOG35-55), followed by pertussis toxin to induce paralysis in EAE mice. After the induction of EAE in mice, the animals intraperitoneally received serial doses of HIV-1 Tat clade B and C (5, 10, and 20 µg/kg body weight) when the early clinical manifestations of EAE were initiated. The results showed that the administration of both clades of the Tat protein led to a marked decrease in the clinical score of EAE mice, as well as improvement in motor-neuron functions. In line with this, Tat considerably reduced the number of apoptotic cells in the sacral region of the spinal cord through the upregulation expression of the Bcl-2 protein. Besides, proinflammatory cytokines such as, IFN-γ, TNF-α, IL-6, and IL-17 were significantly diminished in the serum and spinal cord of EAE mice receiving HIV-1 Tat clade B and C. Conversely, anti-inflammatory cytokines, including IL-10 and IL-4 were elevated in the serum and spinal cord of EAE mice receiving HIV Tat clade B and C when compared with the control group. The immunohistochemical analysis indicated that HIV-1 Tat clade B and C mitigated microgliosis and astrogliosis. The flow cytometry analysis demonstrated that the number of Th1 and Th17cells was significantly decreased in response to TAT administration while the frequency of Th2 cells was markedly increased in the peripheral blood of mice with EAE without influencing the number of T regulatory cells (CD4 + CD25 + forkhead box protein 3 + ). It seems that HIV-1 Tat could be a bona fide therapeutic protein for the alleviation of MS since it has beneficial roles in the suppression of neuroinflammation in MS pathology.

Increased expression of endoplasmic reticulum stress-related caspase-12 and CHOP in the hippocampus of EAE mice.

The role of endoplasmic reticulum (ER) stress has been proposed in several neurodegenerative and autoimmune diseases and may contribute to neural apoptosis. The complex role of ER stress-mediated apoptosis introduces a novel angle on multiple sclerosis (MS) research. Nevertheless, the mechanisms through which ER stress intermediates apoptosis are not entirely understood. To this aim, we examined the expression of C/EBP homologous protein (CHOP), caspase-12, and protein disulfide isomerase (PDI) in mice with experimental autoimmune encephalomyelitis (EAE). We found the upregulated expression of CHOP, caspase-12, and PDI in the brain of EAE mice in comparison to healthy mice. Furthermore, immunofluorescent dual-label staining verified elevated levels of caspase-12/CHOP in astrocytes, oligodendrocytes, and microglia in the hippocampus section of EAE mice. This study highlighted the presence of ER stress and increased activation of caspase-12 in the hippocampus of mice in response to EAE induction. Higher levels of caspase-12/CHOP in hippocampal oligodendrocytes as compared with microglia and astrocytes denote that oligodendrocytes are particularly sensitive to ER-mediated apoptosis. In conclusion, the regulation of ER stress pathway would be beneficial for the survival of oligodendrocyte.

The protective effect of rifampicin on behavioral deficits, biochemical, and neuropathological changes in a cuprizone model of demyelination.

Multiple sclerosis (MS) is a disease of the central nervous system (CNS) in which both neuroinflammation and neurodegeneration play critical roles in the pathogenesis of the disease. A growing body of evidence indicates that some antibiotics have anti-inflammatory and neuroprotective properties. Rifampicin, commonly used for the treatment of mycobacteria, has been shown to exert neuroprotective activities in neurodegenerative diseases. In this study, we examined the efficacy of rifampicin on demyelination, gliosis, apoptosis, inflammation, behavioral dysfunction, and biochemical alterations in the cuprizone model of demyelination. For this aim, male C57BL/6J mice were fed a chow containing 0.2% cuprizone (w/w) for 6 weeks to induce reversible demyelination in the corpus callosum. Mice intraperitoneally received serial doses of rifampicin (10, 20, or 40 mg/kg body weight) in the last 7 days of a 6-week period of cuprizone treatment. The results showed that the administration of rifampicin led to the improvement in motor behavioral deficits. In line with this, rifampicin decreased the number of apoptotic cells in the corpus callosum thereby diminishing the expression of cleaved caspase-3 and Bax, as well as increasing Bcl-2. Moreover, rifampicin significantly lowered the levels of interleukin-6, interleukin-1ß, caspase-12 activity, heme oxygenase-1(HO-1), nitric oxide (NO), and malondialdehyde (MDA) in mice treated with cuprizone. Conversely, the activity of glutathione peroxidase (GPx) and the level of ferric reducing ability of plasma (FRAP) were increased in response to the treatment with rifampicin. Histopathological findings demonstrated that rifampicin statistically promoted remyelination and mitigated microgliosis and astrogliosis. It seems that rifampicin is able to be added to the armamentarium of therapies for multiple sclerosis.

The levels of soluble forms of CD21 and CD83 in multiple sclerosis.

Multiple Sclerosis (MS) is a neuroinflammatory disease of the central nervous system (CNS) in which immune system plays a crucial role in progression of the disease. An enormous amount of research has been shown that immune mediators such as cytokines and chemokines are the culprits of MS propagation suggesting that modulation of such molecules may pave the path to hinder the disease development. It has been shown that both CD21 and CD83 contribute to the resolution of inflammation occurred in MS. CD21 and CD83 have also been ascribed to Epstein Barr virus (EBV) infection (the prime suspect of MS causality) and the levels of vitamin D, respectively. Hence, in this study, we measured the serum concentrations of soluble forms of CD21 and CD83 in 255 patients with MS divided into two groups who were receiving interferon-beta (185 MS patients) and fingolimod (70 MS patients) in comparison to 384 healthy individuals. The levels of EBV titers including anti-VCA IgM, anti-VCA IgG and anti-EBNA-1 IgG were also measured. The results showed that the concentration of soluble CD21 (sCD21) was markedly decreased in serum samples of MS patients with respect of controls. Contrarily, the level of soluble CD83 (sCD83) was elevated in MS patients compared to healthy individuals. In addition, the levels of sCD21 and sCD83 were correlated with the titers of EBV. The data showed the significant association between the expanded disability status scale (EDSS) and the levels of both sCD21 and sCD83. It seems that both sCD21 and sCD83 might be good candidate for disease monitoring and can be considered potential biomarkers for the disease activity.

Minocycline decreases CD36 and increases CD44 in LPS-induced microglia.

Microglia are the resident macrophages patrolling the central nervous system (CNS) to find dangerous signals and infectious agents mediating catastrophic cascades resulting in neuronal degeneration. Their morphological and biochemical properties made them enable to swift activation in response to neural insults and site-directed phagocytosis. Beside of beneficial roles in homeostasis of the brain and spinal cord, microglia can be participating in neuronal destruction and propagation of inflammation when they are unregulated or hyper-activated. A large body of research indicates that various cluster of differentiations (CDs) contribute to flame/quench the inflammatory processes occurred in immune system. In this study, we investigated the expression of CD36 and CD44 in LPS-activated primary rat microglia in response to treatment of minocycline at the levels of protein and gene using flow cytometry and real-time PCR, respectively. The results showed that minocycline decreased the expression of CD36 in cells treated with minocycline with respect to cells treated with LPS. Inversely, the expression of CD44 was increased in cells treated with minocycline in comparison to LPS-induced microglia. It seems that minocycline can modulate the expression of CDs involved in inflammatory reactions and enrich the armamentarium of therapeutic agents used for the treatment of neuroinflammatory and neurodegenerative disorders.

The effect of minocycline on indolamine 2, 3 dioxygenase expression and the levels of kynurenic acid and quinolinic acid in LPS-activated primary rat microglia.

Microglia are one of the most important neural cells in the central nervous system (CNS) which account for 10-15% of all cells found in the brain. A vast majority of studies indicate that microglia play a pivotal role in protection and damage of the CNS. It has been shown that microglia are mainly scavenger cells but also produce a barrage of factors that are involved in tissue repair and neural regeneration. Several lines of evidence indicate that unregulated activation of microglia in response to either endogenous or exogenous insults results in the production of toxic factors that propagate neuronal injury. Studies demonstrated that the activated microglia secret the excessive amounts of quinolinic acid (QA) and kynurenic acid (KYNA) which are highly toxic for the neuronal cells. In line with this, indolamine 2, 3 dioxygenase (IDO), an enzyme producing KYNA and QA has been shown to be elevated during the inflammation in microglia. In this study, we established primary microglial cell cultures obtained from cerebral cortices of 1-day neonatal Wistar rats. Minocycline (20-60 µM) or its vehicle was added to the culture media 60 min prior to 48 h incubation with lipopolysaccharide (LPS; 10 ng/mL). Using a specific process of adhesion and shaking of the cultured glial cells, a purified culture of approximately 94% enriched microglia was obtained and then, corroborated by immunocytochemistry (ICC). The cell viability after minocycline treatments was assessed using the MTT colorimetric assay. The expression of IDO was evaluated using qPCR. The levels of KYNA and QA were determined using enzyme-linked immunosorbent assay (ELISA). The results showed that minocycline significantly decreased the levels of both KYNA and QA in glia cells exposed to LPS. Moreover, minocycline decreased the expression of IDO in treated LPS-induced microglia. It seems that minocycline has a potent ability to oppress the inflammatory process via the decrease in production of IDO expression and the concentrations of KYNA and QA.

Cytomegalovirus and varicella zoster virus seropositivity of Iranian patients with multiple sclerosis: A population-based study.

Multiple Sclerosis is a demyelinating disease of the central nervous system (CNS) affecting young individuals with age range of 20-40years of age. The precise mechanism underlying the disease is still unclear. Some viruses have been proposed to play roles in disease causation. In this study, we recruited 800 MS patients along with 1000 healthy individuals to determine the seropositivity of anti-CMV and anti-VZV IgG titers using enzyme-linked immunosorbent assay (ELISA). Our results showed significant higher titers of anti-CMV and anti-VZV IgG titers in serum of MS patients with respect to healthy individuals (for both p<0.001). It seems that CMV and VZV play a key role in MS pathogenesis.