MxA Protein Levels Research Articles

Leflunomide/hydroxychloroquine combination therapy targets type I IFN-associated proteins in patients with Sjögren’s syndrome that show potential to predict and monitor clinical response

ObjectivesTo assess to what extent leflunomide (LEF) and hydroxychloroquine (HCQ) therapy in patients with primary Sjögren’s syndrome (RepurpSS-I) targets type I IFN-associated responses and to study the potential of several...

Elevated blood MxA protein levels in children with newly diagnosed B-ALL: A prospective case-control study

Background/Aim: Although leukemia is thought to be triggered or initiated by viral infections, it is not clear which viruses are the causative agents for which stage of the disease. Previous studies have shown that the MxA protein is expressed from blood mononuclear cells in reply to inducement of type I interferons in viral infections. Viral infections may trigger childhood B-cell acute lymphoblastic leukemia (B-ALL), and the hypothesis of this study was the detection of the presence of viral infection by measuring MxA expression in blood mononuclear cells of recently diagnosed pediatric B-ALL patients as a surrogate viral marker. Methods: This study consisted two groups; the study group consisted of 30 newly diagnosed B-ALL and the control group consisted of 29 healthy asymptomatic children of similar age. Proven bacterial infection and COVID-19 PCR positivity were exclusion criteria. Bacterial culture of peripheral blood, complete blood count, plasma CRP levels and whole blood MxA levels detected by ELISA (Enzyme-Linked ImmunoSorbent Assay) method were taken. Results: The patients’ mean age was 7.42 years in the leukemia group (previously mentioned as study group) and 7.25 years in the control group. Routine serologic studies for newly diagnosed leukemia patients (CMV, EBV VCA and Hepatitis B IgM, anti-HCV and anti-HIV) were negative in all patients without any bacterial infection detected. The MxA levels were found significantly higher in children with B-ALL than in control group (5.84 (2.18-199.38) and 2.45 (1.17-88.65) ngr/ml, respectively, with P

Blood MxA protein as a marker for respiratory virus infections in young children

BackgroundType I interferon induced MxA response can differentiate viral from bacterial infections, but MxA responses in rhinovirus or asymptomatic virus infections are not known. ObjectiveTo study MxA protein levels in healthy state and during respiratory virus infection of young children in an observational prospective cohort. Study designBlood samples and nasal swabs were collected from 153 and 77 children with and without symptoms of respiratory infections, respectively. Blood MxA protein levels were measured by an enzyme immunoassay and PCR methods were used for the detection of respiratory viruses in nasal swabs. ResultsRespiratory viruses were detected in 81% of symptomatic children. They had higher blood MxA protein levels (median [interquartile range]) than asymptomatic virus-negative children (695 [345–1370] μg/L vs. 110 [55–170] μg/L; p<0.001). Within asymptomatic children, no significant difference was observed in MxA responses between virus-positive and virus-negative groups. A cut-off level of 175μg/L had 92% sensitivity and 77% specificity for a symptomatic respiratory virus infection. Rhinovirus, respiratory syncytial virus, parainfluenza virus, influenza virus, coronavirus, and human metapneumovirus infections were associated with elevated MxA responses. Asymptomatic virus-negative children vaccinated with a live virus vaccine had elevated MxA protein levels (240 [120–540] μg/L), but significantly lower than children with an acute respiratory infection, who had not received vaccinations (740 [350–1425] μg/L; p<0.001). ConclusionBlood MxA protein levels are increased in young children with symptomatic respiratory virus infections, including rhinovirus infections. MxA is an informative general marker for the most common acute virus infections.

Type I interferon signature is high in lupus and neuromyelitis optica but low in multiple sclerosis

Objective Neuromyelitis optica (NMO) is characterized by selective inflammation of the spinal cord and optic nerves but is distinct from multiple sclerosis (MS). Interferon (IFN)-β mitigates disease activity in MS, but is controversial in NMO, with a few reports of disease worsening after IFN-β therapy in this highly active disease. In systemic lupus erythematosus (SLE), IFNs adversely affect disease activity. This study examines for the first time whether serum IFN-α/β activity and IFN-β-induced responses in peripheral blood mononuclear cells (MNC) are abnormally elevated in NMO, as they are in SLE, but contrast to low levels in MS. Methods Serum type I IFN-α/β activity was measured by a previously validated bioassay of 3 IFN-stimulated genes (RT-PCR sensitivity, 0.1 U/ml) rather than ELISA, which has lower sensitivity and specificity for measuring serum IFNs. IFN responses in PBMNC were assessed by in vitro IFN-β-induced activation of phospho-tyrosine-STAT1 and phospho-serine-STAT1 transcription factors, and MxA proteins using Western blots. Results Serum IFN-α/β activity was highest in SLE patients, followed by healthy subjects and NMO, but was surprisingly low in therapy-naïve MS. In functional assays in vitro, IFN-β-induced high levels of P-S-STAT1 in NMO and SLE, but not in MS and controls. IFN-β-induced MxA protein levels were elevated in NMO and SLE compared to MS. Conclusions Serum IFN activity and IFN-β-induced responses in PBMNC are elevated in SLE and NMO patients versus MS. This argues for similarities in pathophysiology between NMO and SLE and provides an explanation for IFN-induced disease worsening in NMO.

Hepatocellular MxA protein expression supports the differentiation of recurrent hepatitis C disease from acute cellular rejection after liver transplantation

Differentiation of recurrent hepatitis C virus (HCV) disease from acute cellular rejection (ACR) following liver transplantation can be difficult. Previously, we have found that MxA protein, a specific and sensitive marker for type 1 interferon production, is strongly expressed in chronic HCV disease. Here, we investigate MxA expression as a marker for recurrent HCV disease in the livers of 14 adult HCV patients who underwent liver transplantation. Serial liver biopsies available for 12 of these patients were stained for MxA protein and scored using a semi-quantitative approach. Hepatocellular MxA protein levels were significantly up-regulated (p = 0.025) in recurrent HCV disease in comparison to ACR. In biopsies that showed histological changes consistent with recurrent HCV disease, strong hepatocellular MxA staining was present in 14/18 (78%). In the liver biopsies with histological evidence of ACR, strong MxA hepatocellular staining was present in only three of 10 (30%). Thus, assessment of hepatocellular MxA protein expression can contribute to the differential diagnosis of ACR and recurrent HCV disease following liver transplantation. In conclusion, analysis of intrahepatic MxA levels has the potential to reduce the inappropriate use with high-dose pulsing of steroids post-operatively.

MxA protein induction in MS patients treated with intramuscular IFNβ-1a

MxA protein production in peripheral blood leukocytes is a valuable marker to evaluate biologic effects of interferon-beta (IFNbeta) therapy in multiple sclerosis (MS) patients. The three IFNbeta preparations available in the treatment of MS differ with respect to antigenicity and biologic activity. We studied prospectively the induction of MxA protein and the development of binding (BAb) and neutralising antibodies (NAb) in nine relapsing-remitting MS (RRMS) patients during one year of intramuscular IFNbeta -1a (Avonex) treatment. Another nine RRMS patient treated with Avonex for 1-3.5 years were also included. The results were compared with our earlier published data of subcutaneous IFNbeta-1a (Rebif). None of these 18 patients developed NAb but three of the long-term patients developed BAb. The baseline MxA protein levels rose but the induction was weaker compared to Rebif. The stimulation index (MxA after/before IFNbeta-1a injection) remained elevated. Weekly intramuscular dosing of IFNbeta-1a provides a sustained effect on lymphocytes but differences in leukocyte stimulation may underlie some of the differences between IFNbeta therapies.

EXPRESSION OF MxA PROTEIN IN BLOOD LYMPHOCYTES OF CHILDREN RECEIVING ANTICANCER CHEMOTHERAPY

The aim of the study was to evaluate whether IFN-α/β-inducible MxA protein expression in children receiving anticancer treatment can be used as an indicator for virus infections during the febrile episodes. Twenty-six children with mainly hematological malignancies entered the study. Children with laboratory-confirmed virus infections had clearly elevated MxA protein levels compared to their counterparts with bacterial or unknown etiology. MxA protein expression increased moderately following the administration of cytostatic agents, even though these children had no clinical signs of infection.

Expression of the antiviral protein MxA in cells transiently perturbs endocytosis

MxA is an interferon-induced antiviral protein. Viral replication relies on the trafficking machinery of the host cell. Overexpression of MxA was found to perturb trafficking of internalized transferrin resulting in its accumulation in cells. Interestingly, this perturbation of endocytic trafficking was transient—with a maximal effect being seen 5–6h after transfection. By 12h after transfection the perturbation of endocytosis was seen to have subsided although MxA protein levels remained elevated even 24h after transfection. The accumulation of transferrin is due to a block in transferrin recycling. It is further shown that MxA can physically associate with the endocytic protein dynamin, possibly accounting for the observed effect of MxA expression on transferrin endocytosis. These results uncover a hitherto unknown aspect of MxA action on trafficking processes within cells.

Altered patterns of cellular gene expression by JC virus

The restricted tropism of the polyomavirus JC virus (JCV) makes pathogenesis-related studies challenging. Because of the difficulties in cultivating JCV, most pathogenesis studies have employed SV40-derived cell lines or JCV/SV40 chimeras that utilize composite enhancer sequences from both viruses. Our objective was to study the early genes expressed by JCV to better understand viral gene regulation. Subconfluent monolayers of primary human fetal glial (PHFG) cells were transfected with ligated full-length JCV DNA and replication was confirmed at days 5 and 10. Total cellular RNA was extracted on day 10 from JCVand mock-transfected PHFG cells. 20 μg RNA was hybridized to an Affymetrix U133A chip, and the data was analyzed using Microarray Suite 5.0. Of the 400 differentially expressed genes, up-regulated genes clustered into 3 major functional groups: cell proliferation, cell-communication, and IFN-responsive genes. Upregulation of IFNinducible genes such as, MxA, Stat1, OAS1 and cig5 was confirmed by realtime PCR. Based on Western blot analysis cig5 and MxA protein levels were significantly elevated. Correlation of T-antigen and agnoprotein gene expression with both mRNA and protein accumulation of antiviral genes such as, MxA and cig5 at an early stage of viral replication suggests that induction of IFN-inducible genes constitutes one of the first cellular response to JCV replication and viral transcription, and its regulation is orchestrated via virusinduced binding of transcription factors. The global analysis of changes in mRNA expression levels following viral infection offers a catalog of genes that are modulated as a result of the host-pathogen interaction and provides a new approach for the investigation of PML pathogenesis.

In vivo and in vitro induction of MxA protein in peripheral blood mononuclear cells from patients chronically infected with hepatitis C virus.

To test whether (HCV) persistence is related to interferon (IFN) hyporesponsiveness, peripheral blood monuclear cells from 29 patients and 11 controls were studied for MxA protein expression. In vitro, only IFN-alpha (P<.001) and interleukin-2 (P<.05) induced MxA protein expression above unstimulated levels. Forty patients were treated with IFN-alpha2b. Patients showed higher basal levels of MxA protein (P<.02) and 2',5'-oligoadenylate synthase (2-5A) activity (P<.05) than controls. During therapy, MxA protein levels (P<.001) and 2-5A activity (P<.05) increased; after 1 month, MxA levels remained high, whereas 2-5A activity declined to initial levels. Increases in MxA were inversely correlated with decreases in serum alanine aminotransferase levels, and MxA induction was greater among virological responders. Thus, the IFN system seems to be activated in chronic HCV infection, but HCV appears to modulate these two components of the IFN system differentially. These results suggest that an inefficient response may contribute to virus persistence and affect the therapeutic outcome.

The MxA protein levels in whole blood lysates of patients with various viral infections

Interferon alpha (IFN α), a type I interferon, can be considered as a viral infection marker because this cytokine is induced during many viral infections. However, it is quite difficult to detect IFN α in sera. Investigations are interested in various intra-cellular IFN α-induced proteins as viral infection markers. However the activity of these enzymes increased not only in response to type I IFNs but also to type II IFN. MxA protein can be detected in the cytoplasm of IFN α/ β-treated cells, whereas other cytokines, including IFN γ, are poor inducers. Using an immunochemiluminescent assay, we studied MxA protein in whole blood of 34 patients with various viral infections. The whole blood was drawn into sterile vacuum tubes containing heparin or EDTA. MxA values were relatively similar in heparin-treated samples and EDTA-treated samples, with differences not exceeding 1 ng/ml. The levels of MxA protein were compared in whole blood obtained by using two different lysis procedures. A correlation was found between the MxA levels obtained by using procedure I and procedure II, but higher amounts of MxA protein were found with procedure II. The second procedure is rapid and more convenient than the other and it is carried out in one step which reduce technical problems. High levels of MxA protein were found in peripheral blood cells of patients with acute viral infections (Rotavirus, Adenovirus, RSV, CMV), but MxA protein was not elevated in bacterial infections. The MxA levels were also studied in peripheral blood of 32 HCV positive patients. MxA protein was not found in most of IFN α-untreated patients, even those with high viral load. In contrast, high levels of MxA protein were found in IFN α-treated patients. MxA quantitation can be considered as a specific marker of acute viral infections, and could be useful in the management of treatment with IFN α.

Impaired interferon induction of human MxA protein in chronic hepatitis B virus infection

MxA protein is interferon inducible, and its role as an antiviral mediator is being studied in various viral diseases. Several cytokines, including type 1 interferons (alpha and beta), interleukins 2 and 12, and granulocyte, macrophage, and granulocyte-macrophage colony-stimulating factors, were tested for their ability to induce human MxA protein synthesis in peripheral blood mononuclear cells from 15 chronic hepatitis B virus-infected patients and 6 healthy subjects as controls. Constitutive MxA expression was scarce in patients and controls but increased significantly in response to type I interferons. MxA responsiveness to interferon alpha was diminished significantly in chronic hepatitis B patients, compared with healthy donors (P < 0.05); this effect was more marked in patients with high viremia levels. Interleukins 2 and 12, and none of the colony-stimulating factors tested, induced low, but detectable, MxA protein levels. These results indicate that chronic infection by hepatitis B virus may impair activation of the immune cells and their capacity to respond to type 1 interferons.

Strong transient expression of the type I interferon-induced MxA protein in hepatitis A but not in acute hepatitis B and C

The human MxA protein is a new specific marker for type I interferon activity both in vitro and in vivo. In the study presented here, this interferon-induced marker, as well as the 2',5'-oligoadenylate synthetases, was measured in circulating mononuclear cells from 21 patients with acute hepatitis A, 20 patients with acute hepatitis B and 14 patients with acute hepatitis C for determination of the activation of the interferon system in these viral diseases. In acute hepatitis A a strong expression (10 of 10 patients) of the MxA protein and the 2',5'-oligoadenylate synthetase activity in peripheral-blood mononuclear cells was observed during the first 2 wk after onset of clinical symptoms. In this period the MxA protein concentrations reached levels similar to those measured in patients treated with up to 5 x 10(6) IU interferon-alpha three times a week. Beyond wk 3, in eight of eight patients with hepatitis A no increased MxA protein levels were found. In contrast, peripheral-blood mononuclear cells from patients with acute hepatitis B contained either no measurable MxA protein or only slightly higher levels of the MxA protein, as did those of most patients (12 of 14) with acute hepatitis C. The MxA protein levels of both hepatitis B and C patients were significantly lower (p < 0.05) than those found in hepatitis A patients. Furthermore, sera from 6 of 10 patients with hepatitis A, but none of 10 patients with acute hepatitis B and C, contained measurable MxA protein. This serum MxA protein may originate from interferon-exposed and subsequently damaged liver cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Control of IFN-inducible MxA gene expression in human cells.

MxA is an IFN-induced human protein which is located in the cytoplasm of induced cells. MxA makes the cells resistant to infection by influenza and vesicular stomatitis viruses. In the present work we used baculovirus expression system to produce MxA protein. The protein was purified to homogeneity and highly specific polyclonal anti-MxA antibodies were prepared. In human mononuclear cells, and A549 lung carcinoma cells expression of MxA protein is induced by very low (< 1 IU/ml) doses of leukocyte IFN-alpha (nIFN-alpha), whereas IFN-gamma does not seem to induce it or potentiate the induction by IFN-alpha. In mononuclear cells stimulated with high doses of leukocyte IFN-alpha concentrations, the amount of MxA mRNA was induced 10-fold at 4 h after IFN induction and up to 10-fold higher MxA protein levels were observed at 24-48 h postinduction. The gene can be reinduced by IFN-alpha 24 h after the initial induction suggesting for a lack of negative feedback after this time point. The protein is very stable, the half-life being approximately 2.3 days. Flow cytometric analysis revealed that monocytes have higher basal and induced MxA protein levels than lymphocytes but the dose-dependency of MxA expression is very similar in both cell types. Granulocytes are producing very low amounts of MxA protein.