CD80+ and CD86+ B cells as biomarkers and possible therapeutic targets in HTLV-1 associated myelopathy/tropical spastic paraparesis and multiple sclerosis

A Dual Role of Osteopontin in Modifying B Cell Responses

The occurrence of B cell aggregates within the central nervous system (CNS) has prompted the investigation of the potential sources of pathogenic B cell and T cell responses in a subgroup of secondary progressive multiple sclerosis (MS) patients. Nevertheless, the expression profile of molecules associated with these aggregates and their role in aggregate development and persistence is poorly described. Here, we focused on the expression pattern of osteopontin (OPN), which is a well-described cytokine, in MS brain tissue. Autopsied brain sections from MS cases with and without B cell pathology were screened for the presence of CD20⁺ B cell aggregates and co-expression of OPN. To demonstrate the effect of OPN on B cells, flow cytometry, ELISA and in vitro aggregation assays were conducted using the peripheral blood of healthy volunteers. Although OPN was expressed in MS brain tissue independent of B cell pathology, it was also highly expressed within B cell aggregates. In vitro studies demonstrated that OPN downregulated the co-stimulatory molecules CD80 and CD86 on B cells. OPN-treated B cells produced significantly lower amounts of IL-6. However, OPN-treated B cells also exhibited a higher tendency to form homotypic cell aggregates in vitro. Taken together, our data indicate a conflicting role of OPN in modulating B cell responses.

Immunovirological and environmental screening reveals actionable risk factors for fatal COVID-19 during post-vaccination nursing home outbreaks

Coronavirus Disease 2019 (COVID-19) vaccination has resulted in excellent protection against fatal disease, including in older adults. However, risk factors for post-vaccination fatal COVID-19 are largely unknown. We comprehensively studied three large nursing home outbreaks (20-35% fatal cases among residents) by combining severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) aerosol monitoring, whole-genome phylogenetic analysis and immunovirological profiling of nasal mucosa by digital nCounter transcriptomics. Phylogenetic investigations indicated that each outbreak stemmed from a single introduction event, although with different variants (Delta, Gamma and Mu). SARS-CoV-2 was detected in aerosol samples up to 52 d after the initial infection. Combining demographic, immune and viral parameters, the best predictive models for mortality comprised IFNB1 or age, viral ORF7a and ACE2 receptor transcripts. Comparison with published pre-vaccine fatal COVID-19 transcriptomic and genomic signatures uncovered a unique IRF3 low/IRF7 high immune signature in post-vaccine fatal COVID-19 outbreaks. A multi-layered strategy, including environmental sampling, immunomonitoring and early antiviral therapy, should be considered to prevent post-vaccination COVID-19 mortality in nursing homes.

Longitudinal analysis of immunocyte responses and inflammatory cytokine profiles in SFTSV-infected rhesus macaques

Severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging bunyavirus, causes severe fever with thrombocytopenia syndrome (SFTS), with a high fatality rate of 20%-30%. At present, however, the pathogenesis of SFTSV remains largely unclear and no specific therapeutics or vaccines against its infection are currently available. Therefore, animal models that can faithfully recapitulate human disease are important to help understand and treat SFTSV infection. Here, we infected seven Chinese rhesus macaques (Macaca mulatta) with SFTSV. Virological and immunological changes were monitored over 28 days post-infection. Results showed that mild symptoms appeared in the macaques, including slight fever, thrombocytopenia, leukocytopenia, increased aspartate aminotransferase (AST) and creatine kinase (CK) in the blood. Viral replication was persistently detectable in lymphoid tissues and bone marrow even after viremia disappeared. Immunocyte detection showed that the number of T cells (mainly CD8⁺ T cells), B cells, natural killer (NK) cells, and monocytes decreased during infection. In detail, effector memory CD8⁺ T cells declined but showed increased activation, while both the number and activation of effector memory CD4⁺ T cells increased significantly. Furthermore, activated memory B cells decreased, while CD80⁺/CD86⁺ B cells and resting memory B cells (CD27⁺CD21⁺) increased significantly. Intermediate monocytes (CD14⁺CD16⁺) increased, while myeloid dendritic cells (mDCs) rather than plasmacytoid dendritic cells (pDCs) markedly declined during early infection. Cytokines, including interleukin-6 (IL-6), interferon-inducible protein-10 (IP-10), and macrophage inflammatory protein 1 (MCP-1), were substantially elevated in blood and were correlated with activated CD4⁺ T cells, B cells, CD16⁺CD56⁺ NK cells, CD14⁺CD16⁺ monocytes during infection. Thus, this study demonstrates that Chinese rhesus macaques infected with SFTSV resemble mild clinical symptoms of human SFTS and provides detailed virological and immunological parameters in macaques for understanding the pathogenesis of SFTSV infection.

Systemic cytokines and GlycA discriminate disease status and predict corticosteroid response in HTLV-1-associated neuroinflammation

BACKGROUND

HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) is an incapacitating neuroinflammatory disorder for which no disease-modifying therapy is available, but corticosteroids provide some clinical benefit. Although HAM/TSP pathogenesis is not fully elucidated, older age, female sex and higher proviral load are established risk factors. We investigated systemic cytokines and a novel chronic inflammatory marker, GlycA, as possible biomarkers of immunopathogenesis and therapeutic response in HAM/TSP, and examined their interaction with established risk factors.

PATIENTS AND METHODS

We recruited 110 People living with HTLV-1 (PLHTLV-1, 67 asymptomatic individuals and 43 HAM/TSP patients) with a total of 946 person-years of clinical follow-up. Plasma cytokine levels (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, TNF) and GlycA were quantified by Cytometric Bead Array and ¹NMR, respectively. Cytokine signaling and prednisolone response were validated in an independent cohort by nCounter digital transcriptomics. We used multivariable regression, machine learning algorithms and Bayesian network learning for biomarker identification.

RESULTS

We found that systemic IL-6 was positively correlated with both age (r = 0.50, p < 0.001) and GlycA (r = 0.45, p = 0.00049) in asymptomatics, revealing an 'inflammaging" signature which was absent in HAM/TSP. GlycA levels were higher in women (p = 0.0069), but cytokine levels did not differ between the sexes. IFN-γ (p = 0.007) and IL-17A (p = 0.0001) levels were increased in untreated HAM/TSP Multivariable logistic regression identified IL-17A and proviral load as independent determinants of clinical status, resulting in modest accuracy of predicting HAM/TSP status (64.1%), while a machine learning-derived decision tree classified HAM/TSP patients with 90.7% accuracy. Pre-treatment GlycA and TNF levels significantly predicted clinical worsening (measured by Osame Motor Disability Scale), independent of proviral load. In addition, a poor prednisolone response was significantly correlated with higher post-treatment IFN-γ levels. Likewise, a transcriptomic IFN signaling score, significantly correlated with previously proposed HAM/TSP biomarkers (CASP5/CXCL10/FCGR1A/STAT1), was efficiently blunted by in vitro prednisolone treatment of PBMC from PLHTLV-1 and incident HAM/TSP.

CONCLUSIONS

An age-related increase in systemic IL-6/GlycA levels reveals inflammaging in PLHTLV-1, in the absence of neurological disease. IFN-γ and IL-17A are biomarkers of untreated HAM/TSP, while pre-treatment GlycA and TNF predict therapeutic response to prednisolone pulse therapy, paving the way for a precision medicine approach in HAM/TSP.

Integration of genomic variants and bioinformatic-based approach to drive drug repurposing for multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease in the central nervous system (CNS) marked by inflammation, demyelination, and axonal loss. Currently available MS medication is limited, thereby calling for a strategy to accelerate new drug discovery. One of the strategies to discover new drugs is to utilize old drugs for new indications, an approach known as drug repurposing. Herein, we first identified 421 MS-associated SNPs from the Genome-Wide Association Study (GWAS) catalog (p-value < 5 × 10-8), and a total of 427 risk genes associated with MS using HaploReg version 4.1 under the criterion r 2  > 0.8. MS risk genes were then prioritized using bioinformatics analysis to identify biological MS risk genes. The prioritization was performed based on six defined categories of functional annotations, namely missense mutation, cis-expression quantitative trait locus (cis-eQTL), molecular pathway analysis, protein-protein interaction (PPI), genes overlap with knockout mouse phenotype, and primary immunodeficiency (PID). A total of 144 biological MS risk genes were found and mapped into 194 genes within an expanded PPI network. According to the DrugBank and the Therapeutic Target Database, 27 genes within the list targeted by 68 new candidate drugs were identified. Importantly, the power of our approach is confirmed with the identification of a known approved drug (dimethyl fumarate) for MS. Based on additional data from ClinicalTrials.gov, eight drugs targeting eight distinct genes are prioritized with clinical evidence for MS disease treatment. Notably, CD80 and CD86 pathways are promising targets for MS drug repurposing. Using in silico drug repurposing, we identified belatacept as a promising MS drug candidate. Overall, this study emphasized the integration of functional genomic variants and bioinformatic-based approach that reveal important biological insights for MS and drive drug repurposing efforts for the treatment of this devastating disease.

Identification of a novel role for matrix metalloproteinase-3 in the modulation of B cell responses in multiple sclerosis

There has been a growing interest in the presence and role of B cell aggregates within the central nervous system of multiple sclerosis patients. However, very little is known about the expression profile of molecules associated with these aggregates and how they might be influencing aggregate development or persistence in the brain. The current study focuses on the effect of matrix metalloproteinase-3, which is associated with B cell aggregates in autopsied multiple sclerosis brain tissue, on B cells. Autopsied brain sections from multiple sclerosis cases and controls were screened for the presence of CD20⁺ B cell aggregates and expression of matrix metalloproteinase-3. Using flow cytometry, enzyme-linked immunosorbent assay and gene array as methods, in vitro studies were conducted using peripheral blood of healthy volunteers to demonstrate the effect of matrix metalloproteinase-3 on B cells. Autopsied brain sections from multiple sclerosis patients containing aggregates of B cells expressed a significantly higher amount of matrix metalloproteinase-3 compared to controls. In vitro experiments demonstrated that matrix metalloproteinase-3 dampened the overall activation status of B cells by downregulating CD69, CD80 and CD86. Furthermore, matrix metalloproteinase-3-treated B cells produced significantly lower amounts of interleukin-6. Gene array data confirmed that matrix metalloproteinase-3 altered the proliferation and survival profiles of B cells. Taken together, out data indicate a role for B cell modulatory properties of matrix metalloproteinase-3.

Comprehensive Flow Cytometry Profiling of the Immune System in COVID-19 Convalescent Individuals

SARS-CoV-2 has infected more than 200 million people worldwide, with more than 4 million associated deaths. Although more than 80% of infected people develop asymptomatic or mild COVID-19, SARS-CoV-2 can induce a profound dysregulation of the immune system. Therefore, it is important to investigate whether clinically recovered individuals present immune sequelae. The potential presence of a long-term dysregulation of the immune system could constitute a risk factor for re-infection and the development of other pathologies. Here, we performed a deep analysis of the immune system in 35 COVID-19 recovered individuals previously infected with SARS-CoV-2 compared to 16 healthy donors, by flow cytometry. Samples from COVID-19 individuals were analysed from 12 days to 305 days post-infection. We observed that, 10 months post-infection, recovered COVID-19 patients presented alterations in the values of some T-cell, B-cell, and innate cell subsets compared to healthy controls. Moreover, we found in recovered COVID-19 individuals increased levels of circulating follicular helper type 1 (cTfh1), plasmablast/plasma cells, and follicular dendritic cells (foDC), which could indicate that the Tfh-B-foDC axis might be functional to produce specific immunoglobulins 10 months post-infection. The presence of this axis and the immune system alterations could constitute prognosis markers and could play an important role in potential re-infection or the presence of long-term symptoms in some individuals.

Reprogramming the anti-tumor immune response via CRISPR genetic and epigenetic editing

Precise clustered regularly interspaced short palindromic repeats (CRISPR)-mediated genetic and epigenetic manipulation of the immune response has become a promising immunotherapeutic approach toward combating tumorigenesis and tumor progression. CRISPR-based immunologic reprograming in cancer therapy comprises the locus-specific enhancement of host immunity, the improvement of tumor immunogenicity, and the suppression of tumor immunoevasion. To date, the ex vivo re-engineering of immune cells directed to inhibit the expression of immune checkpoints or to express synthetic immune receptors (chimeric antigen receptor therapy) has shown success in some settings, such as in the treatment of melanoma, lymphoma, liver, and lung cancer. However, advancements in nuclease-deactivated CRISPR-associated nuclease-9 (dCas9)-mediated transcriptional activation or repression and Cas13-directed gene suppression present novel avenues for the development of tumor immunotherapies. In this review, the basis for development, mechanism of action, and outcomes from recently published Cas9-based clinical trial (genetic editing) and dCas9/Cas13-based pre-clinical (epigenetic editing) data are discussed. Lastly, we review cancer immunotherapy-specific considerations and barriers surrounding use of these approaches in the clinic.

Rabbit umbilical cord mesenchymal stem cells: A new option for tissue engineering

BACKGROUND

The source and availability of cells for tissue engineering in large scale research or clinical trials requires special attention. We propose the idea of applying rabbit umbilical cord mesenchymal stem cells for this purpose.

METHODS

Here, the structure of the rabbit umbilical cord was analyzed and compared to that of human umbilical cord, both macroscopically and histologically. Next, we isolated, cultured and identified the proliferative activity and immunological characteristics of rabbit umbilical cord mesenchymal stem cells in vitro using mixed lymphocyte reaction, flow cytometry and an enzyme-linked immunosorbent assay. Furthermore, we evaluated the effects of biphasic calcium phosphate ceramic scaffolds seeded with rabbit umbilical cord mesenchymal stem cells in rat cranial defect models using multiple techniques, including radiological, histological and immunohistochemistry.

RESULTS

In vitro studies demonstated a high level of proliferation and multi-lineage differentiation potential in rabbit umbilical cord mesenchymal stem cells. Rabbit umbilical cord mesenchymal stem cells exibited low immunogenicity properties and immune suppression capability with respect to both the allogeneic and xenogeneic immune response. The results of the in vivo study showed that rabbit umbilical cord mesenchymal stem cells could promote osteogenesis in heterogeneous hosts.

CONCLUSIONS

The rabbit umbilical cord mesenchymal stem cells may be a new source for tissue engineering.

Neurofilament levels are associated with blood–brain barrier integrity, lymphocyte extravasation, and risk factors following the first demyelinating event in multiple sclerosis

Background:

Increased blood brain barrier (BBB) permeability, CNS inflammation and neuroaxonal damage are pathological hallmarks in early multiple sclerosis (MS).

Objective:

To investigate the associations of neurofilament light chain (NfL) levels with measures of BBB integrity and central nervous system (CNS) inflammation in MS during the first demyelinating event.

Methods:

Blood and cerebrospinal fluid (CSF) were obtained from 142 MS (McDonald 2017) treatment-naive patients from the SET study (63% female; age: 29.7 ± 7.9 years) following the disease onset. NfL, albumin, immunoglobulin G (IgG), and immunoglobulin M (IgM) levels were measured in CSF and blood samples. Albumin quotient was computed as a marker of BBB integrity. Immune cell subset counts in CSF were measured using flow cytometry. MS risk factors, such as Human leukocyte antigen DRB1 locus gene ( HLA DRB1)*1501, anti-Epstein–Barr virus (EBV) antibodies, and 25-hydroxy vitamin D3, were also measured.

Results:

Higher serum NfL (sNfL) levels were associated with higher albumin quotient ( p < 0.001), CSF CD80+ ( p = 0.012), and CD80+ CD19+ ( p = 0.015) cell frequency. sNfL levels were also associated with contrast-enhancing and T2 lesions on brain magnetic resonance imaging (MRI; all p ⩽ 0.001). Albumin quotient was not associated with any of the MS risk factors assessed. sNfL levels were associated with anti-EBV viral capsid antigen (VCA) IgG levels ( p = 0.0026).

Conclusion:

sNfL levels during the first demyelinating event of MS are associated with greater impairment of BBB integrity, immune cell extravasation, and brain lesion activity on MRI.

A combination of the activation marker CD86 and the immune checkpoint marker B and T lymphocyte attenuator (BTLA) indicates a putative permissive activation state of B cell subtypes in healthy blood donors independent of age and sex

Background

The use of anti-B cell based therapies in immune-mediated diseases targeting general B cell markers or molecules important for B cell function has increased the clinical needs of monitoring B cell subpopulations.

Results

We analyzed the expression profile of cell surface markers CD86 and B and T lymphocyte attenuator (BTLA) in B cell subtypes using flow cytometry, including naïve, transitional, switched memory, non-switched memory and double-negative memory B cells and plasmablasts, and investigated the dependence of age and sex in a healthy adult blood donor population. The switched memory B cell subtype displayed a divergent expression of the markers, with increased CD86 and decreased BTLA as compared to non-switched and double negative memory cells, as well as compared to naïve B cells. Plasmablasts expressed highly increased CD86 compared to all other subtypes and a decreased expression of BTLA compared to naïve cells, but still higher compared to the memory cell populations. Transitional B cells had CD86 and BTLA expression similar to the other naïve cells.

Conclusions

We show divergent expression of CD86 and BTLA in memory cells and plasmablasts compared to naïve B cells independent of age and sex. Furthermore, a similarly divergent difference of expression pattern was seen between the memory cell subtypes, altogether indicating that the combination of CD86 and BTLA might be markers for a permissive activation state. We suggest the combination of CD86 and BTLA expression on B cell subtypes as a potentially important tool in monitoring the status of B cell subtypes before and after treatments influencing the B cell compartment.

HTLV infected individuals have increased B-cell activation and proinflammatory regulatory T-cells

Human T-lymphotropic virus (HTLV) affects the human immune system in many ways, most notably by inducing proliferation of infected CD4 + T cells, but several other cell types are also affected. To characterize the effects of HTLV infection, we analysed blood samples from HTLV-infected individuals by flow cytometry. Samples were collected from visitors at the HIV clinic in Bissau, Guinea-Bissau. These samples were tested for HTLV and HIV, and 199 were analysed by flow cytometry using panels for B cells, T-cell maturation and activation, regulatory T cells (Tregs) and monocytes. CD80+ cell proportions were significantly higher in HTLV infected than in HTLV uninfected in all B cell subsets. Among T cells, there was no change in cell distribution between maturation stages, but a higher CD25+ proportion among Tregs (61.1 % vs 36.3 %, p < 0.001) in HTLV infected than in HTLV uninfected. The level of CD49d on individual cells was also higher (MFI 2734.5 vs 1,041, p < 0.001). In HTLV infected individuals, CD8 + T cells had a lower proportion of CTLA-4+ (2.5 % vs 3.5 %, 0.048) and higher PD1+ proportion on the CD45RO + subset (81.6 % vs 77.1 %, p < 0.001). Together, these findings point toward reduced regulation in HTLV + patients, which leads to immune activation. This study corroborates previous findings and offers new insight into the effects of HTLV by providing a broad flowcytometric analysis of immune cells in HTLV + individuals.

An evolutionary recent IFN/IL-6/CEBP axis is linked to monocyte expansion and tuberculosis severity in humans

Monocyte counts are increased during human tuberculosis (TB) but it has not been determined whether Mycobacterium tuberculosis (Mtb) directly regulates myeloid commitment. We demonstrated that exposure to Mtb directs primary human CD34⁺ cells to differentiate into monocytes/macrophages. In vitro myeloid conversion did not require type I or type II IFN signaling. In contrast, Mtb enhanced IL-6 responses by CD34⁺ cell cultures and IL-6R neutralization inhibited myeloid differentiation and decreased mycobacterial growth in vitro. Integrated systems biology analysis of transcriptomic, proteomic and genomic data of large data sets of healthy controls and TB patients established the existence of a myeloid IL-6/IL6R/CEBP gene module associated with disease severity. Furthermore, genetic and functional analysis revealed the IL6/IL6R/CEBP gene module has undergone recent evolutionary selection, including Neanderthal introgression and human pathogen adaptation, connected to systemic monocyte counts. These results suggest Mtb co-opts an evolutionary recent IFN-IL6-CEBP feed-forward loop, increasing myeloid differentiation linked to severe TB in humans.

Expression of CD80 and CD86 on B cells during coxsackievirus B3-induced acute myocarditis

Introduction

The pathogenesis of viral myocarditis (VMC) is unclear, but many studies have shown that VMC is associated with an excessive immune response. CD80 and CD86 are important costimulatory molecules that play a critical role in autoimmunity. However, whether CD80+/CD86+ B cells participate in the pathogenesis of acute VMC is unknown.

Material and methods

Male C57BL/6 mice were infected by intraperitoneal injection with coxsackievirus B3 (CVB3) to establish a VMC model. Control mice were administered phosphate-buffered saline intraperitoneally. At one week and two weeks post injection, histopathological changes in heart tissue were assessed with haematoxylin and eosin staining. The frequency of splenic CD80+/CD86+ B cells was measured with flow cytometry.

Results

The frequency of CD80+ B cells was significantly increased in VMC, while the frequency of CD86+ B cells was significantly decreased. Furthermore, the frequency of CD80+ B cells related to the severity of VMC.

Conclusions

These data show that CD80+/CD86+B cells are involved in the pathogenesis of VMC, with CD80+B cells being more important than CD86+B cells.

CD80 Regulates Th17 Cell Differentiation in Coxsackie Virus B3-Induced Acute Myocarditis

The cluster of differentiation protein complex, CD80/CD86, regulates Th1/Th2 differentiation in autoimmune disease. In order to establish the effects of CD80/CD86 on Th17 cell differentiation in acute viral myocarditis (VMC), we infected C57BL/6 mice with Coxsackie virus B3 (CVB3) and examined the effects of the treatment with anti-CD80/CD86 monoclonal antibodies (mAbs) on Th17 cell differentiation in vivo. The effects of anti-CD80/CD86 mAbs on Th17 cell differentiation were further evaluated in vitro. The treatment with anti-CD80 mAb induced marked suppression of Th17 cell differentiation and ROR-γt mRNA expression, whereas anti-CD86 mAb alone had no effect, both in vivo and in vitro. Our finding that CD80 regulates Th17 differentiation supports the potential utility of anti-CD80 mAb as an effective new immunotherapeutic target in acute VMC.

Comprehensive Antiretroviral Restriction Factor Profiling Reveals the Evolutionary Imprint of the ex Vivo and in Vivo IFN-β Response in HTLV-1-Associated Neuroinflammation

HTLV-1-Associated Myelopathy (HAM/TSP) is a progressive neuroinflammatory disorder for which no disease-modifying treatment exists. Modest clinical benefit from type I interferons (IFN-α/β) in HAM/TSP contrasts with its recently identified IFN-inducible gene signature. In addition, IFN-α treatment in vivo decreases proviral load and immune activation in HAM/TSP, whereas IFN-β therapy decreases tax mRNA and lymphoproliferation. We hypothesize this "IFN paradox" in HAM/TSP might be explained by both cell type- and gene-specific effects of type I IFN in HTLV-1-associated pathogenesis. Therefore, we analyzed ex vivo transcriptomes of CD4⁺ T cells, PBMCs and whole blood in healthy controls, HTLV-1-infected individuals, and HAM/TSP patients. First, we used a targeted approach, simultaneously quantifying HTLV-1 mRNA (HBZ, Tax), proviral load and 42 host genes with known antiretroviral (anti-HIV) activity in purified CD4⁺ T cells. This revealed two major clusters ("antiviral/protective" vs. "proviral/deleterious"), as evidenced by significant negative (TRIM5/TRIM22/BST2) vs. positive correlation (ISG15/PAF1/CDKN1A) with HTLV-1 viral markers and clinical status. Surprisingly, we found a significant inversion of antiretroviral activity of host restriction factors, as evidenced by opposite correlation to in vivo HIV-1 vs. HTLV-1 RNA levels. The anti-HTLV-1 effect of antiviral cluster genes was significantly correlated to their adaptive chimp/human evolution score, for both Tax mRNA and PVL. Six genes of the proposed antiviral cluster underwent lentivirus-driven purifying selection during primate evolution (TRIM5/TRIM22/BST2/APOBEC3F-G-H), underscoring the cross-retroviral evolutionary imprint. Secondly, we examined the genome-wide type I IFN response in HAM/TSP patients, following short-term ex vivo culture of PBMCs with either IFN-α or IFN-β. Microarray analysis evidenced 12 antiretroviral genes (including TRIM5α/TRIM22/BST2) were significantly up-regulated by IFN-β, but not IFN-α, in HAM/TSP. This was paralleled by a significant decrease in lymphoproliferation by IFN-β, but not IFN-α treatment. Finally, using published ex vivo whole blood transcriptomic data of independent cohorts, we validated the significant positive correlation between TRIM5, TRIM22, and BST2 in HTLV-1-infected individuals and HAM/TSP patients, which was independent of the HAM/TSP disease signature. In conclusion, our results provide ex vivo mechanistic evidence for the observed immunovirological effect of in vivo IFN-β treatment in HAM/TSP, reconcile an apparent IFN paradox in HTLV-1 research and identify biomarkers/targets for a precision medicine approach.

Inflammatory gene expression signatures in idiopathic intracranial hypertension: possible implications in microgravity-induced ICP elevation

The visual impairment and intracranial pressure (VIIP) syndrome is a neuro–ophthalmologic condition described in astronauts returning from long duration space missions. Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is characterized by a chronic elevation of intracranial pressure (ICP) in the absence of an intracranial mass lesion. Because VIIP and IIH share some neurologic and ophthalmologic manifestations, the latter might be used as a model to study some of the processes underlying VIIP. This work constitutes a preliminary investigation of the molecular pathways associated with the elevation of ICP in IIH. Gene expression signatures were obtained from exosomes collected from CSF and plasma in patients with possible signs of IIH. The gene expression targets focused on inflammatory genes and miRNAs. The results suggest that inflammatory cytokine-driven processes and immune cell migration are activated when ICP is elevated in IIH patients, either as a cause or effect of the ICP increase. Several miRNAs appear to be involved in this response, among which miR-9 and miR-16 are upregulated in CSF and plasma of higher ICP subjects. This study provides evidence in support of neurophysiological alterations and neuro-immunomodulation in this condition. If similar changes are seen in astronauts manifesting with the VIIP syndrome, an underlying pathophysiological basis may be discovered.

People with elevated pressure inside their skulls show signs of inflammation that could be relevant for astronauts on long-duration missions. To better understand the biology of spaceflight-induced visual impairment—a common problem for astronauts that is thought to arise from pressure building up around the brain in microgravity—a team led by Susana Zanello from the NASA Johnson Space Center in Houston, Texas, USA, examined the spinal fluid and blood of individuals with idiopathic intracranial hypertension, a neurologic condition that shares some features with the mysterious syndrome that impairs astronauts’ sight vision. The researchers characterized the RNA contained within tiny secreted particles, known as exosomes, in the patient samples. The expression of several genes and regulatory microRNAs linked to pro-inflammatory immune responses were changed. The authors surmise that similar immune changes could underpin the eyesight syndrome plaguing astronauts.

Evaluation of HTLV-1 HBZ and proviral load, together with host IFN λ3, in pathogenesis of HAM/TSP

Human T-cell lymphotropic virus 1 (HTLV-1) is associated with two progressive diseases: HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia/lymphoma (ATLL). Although HTLV-1 proviral load (PVL) has been introduced as a risk factor for these diseases' progression, it is not sufficient on its own to yield an accurate estimation of the outcome of the infection. In the present study, PVL and HTLV-1 basic leucine zipper factor (HBZ) expression level as viral factors, and IFN λ3 as a host factor, were evaluated in HAM/TSP patients and HTLV-1 asymptomatic carriers (ACs). During 2014-2015, 12 HAM/TSP patients and 18 ACs who had been referred to the HTLV-1 Clinic, Ghaem Hospital, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran, were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) were isolated and the DNA and mRNA were extracted for quantification of HBZ, IFN λ3 expression, and PVL using real-time PCR (TaqMan method). Although the PVL was higher in the HAM/TSP group, with a 94% confidence interval, there were no considerable differences in terms of HBZ mRNA and PVL between ACs and HAM patients. IFN λ3 expression in the HAM/TSP group was significantly higher than in the ACs (P = 0.02). To the best of our knowledge, no study has evaluated the expression level of IFN λ3 in HTLV-1 positive patients. The immune response against HTLV-1 viral antigens and virulent factors will therefore further refine our knowledge of interactions between the virus and host in the pathogenesis of HTLV-1-related disorders. The virus PVL and the host IFN λ3 can be used as pathogenic factors of HTLV-1 infected patients at risk of HAM/TSP manifestation. J. Med. Virol. 89:1102-1107, 2017. © 2016 Wiley Periodicals, Inc.

A Fashi Lymphoproliferative Phenotype Reveals Non-Apoptotic Fas Signaling in HTLV-1-Associated Neuroinflammation

Human T-cell lymphotropic virus (HTLV)-1 was the first human retrovirus to be associated to cancer, namely adult T-cell leukemia (ATL), but its pathogenesis remains enigmatic, since only a minority of infected individuals develops either ATL or the neuroinflammatory disorder HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). A functional FAS -670 polymorphism in an interferon (IFN)-regulated STAT1-binding site has been associated to both ATL and HAM/TSP susceptibility. Fas^hi T stem cell memory (Tscm) cells have been identified as the hierarchical apex of ATL, but have not been investigated in HAM/TSP. In addition, both FAS and STAT1 have been identified in an IFN-inducible HAM/TSP gene signature, but its pathobiological significance remains unclear. We comprehensively explored Fas expression (protein/mRNA) and function in lymphocyte activation, apoptosis, proliferation, and transcriptome, in PBMC from a total of 47 HAM/TSP patients, 40 asymptomatic HTLV-1-infected individuals (AC), and 58 HTLV-1 -uninfected healthy controls. Fas surface expression followed a two-step increase from HC to AC and from AC to HAM/TSP. In HAM/TSP, Fas levels correlated positively to lymphocyte activation markers, but negatively to age of onset, linking Fas^hi cells to earlier, more aggressive disease. Surprisingly, increased lymphocyte Fas expression in HAM/TSP was linked to decreased apoptosis and increased lymphoproliferation upon in vitro culture, but not to proviral load. This Fas^hi phenotype is HAM/TSP-specific, since both ex vivo and in vitro Fas expression was increased as compared to multiple sclerosis (MS), another neuroinflammatory disorder. To elucidate the molecular mechanism underlying non-apoptotic Fas signaling in HAM/TSP, we combined transcriptome analysis with functional assays, i.e., blocking vs. triggering Fas receptor in vitro with antagonist and agonist-, anti-Fas mAb, respectively. Treatment with agonist anti-Fas mAb restored apoptosis, indicating biased, but not defective Fas signaling in HAM/TSP. In silico analysis revealed biased Fas signaling toward proliferation and inflammation, driven by RelA/NF-κB. Correlation of Fas transcript levels with proliferation (but not apoptosis) was confirmed in HAM/TSP ex vivo transcriptomes. In conclusion, we demonstrated a two-step increase in Fas expression, revealing a unique Fas^hi lymphocyte phenotype in HAM/TSP, distinguishable from MS. Non-apoptotic Fas signaling might fuel HAM/TSP pathogenesis, through increased lymphoproliferation, inflammation, and early age of onset.

A Lower Proportion of Regulatory B Cells in Patients with Henoch-Schoenlein Purpura Nephritis

Background

Henoch—Schoenlein purpura is the one of most common types of systemic vasculitis that involves impaired renal function and Henoch-Schoenlein purpura nephritis (HSPN). The diagnosis of this condition is largely based on immunohistologic detection of immunoglobulin A1-containing immune complex in the glomerular deposits of mesangium. Despite clinical advances, the etiopathogenesis of HSPN is still largely unknown.

Methods

In this study, we enrolled 25 newly diagnosed HSPN patients and 14 healthy controls. Then, fractions of B cell subtypes were determined in venous blood using flow cytometry. The serum interleukin (IL)-10 concentration was determined by enzyme-linked immunosorbent assay.

Results

Compared to those in healthy controls, the numbers of CD38⁺CD19⁺, CD86⁺CD19⁺, CD38⁺CD86⁺CD19⁺, and CD95⁺CD19⁺ B cells per microliter of blood were significantly higher in HSPN patients. In contrast, the numbers of CD5⁺CD19⁺, IL-10⁺CD19⁺, CD5⁺CD1d⁺CD19⁺, and IL-10⁺CD5⁺CD1d⁺CD19⁺ B cells per microliter of blood and the serum IL-10 concentration were significantly lower in HSPN patients. Following treatment, the numbers of CD38⁺CD19⁺ and CD86⁺CD19⁺ B cells per microliter of blood were significantly reduced in HSPN patients. However, the numbers of CD5⁺CD1d⁺CD19⁺, CD5⁺CD1d⁺IL-10⁺CD19⁺, and IL-10⁺CD19⁺ B cells per microliter of blood and the serum IL-10 concentration were significantly increased in HSPN patients following treatment. The estimated glomerular filtration rate (eGFR) was negatively correlated with the number of CD38⁺CD19⁺ B cells but positively correlated with the numbers of IL-10⁺CD19⁺, CD1d⁺CD5⁺CD19⁺, and IL-10⁺CD1d⁺CD5⁺CD19⁺B cells per microliter of blood and the serum IL-10 concentration. The 24-h urinary protein concentration was positively correlated with the number of CD38⁺CD19⁺B cells but negatively correlated with the numbers of IL-10⁺CD19⁺, CD1d⁺CD5⁺CD19⁺, and IL-10⁺CD1d⁺CD5⁺CD19⁺B cells per microliter of blood and the serum IL-10 concentration.

Conclusion

Our results suggest that CD38⁺CD19⁺ and CD1d⁺CD5⁺CD19⁺ B cells (Bregs) contribute to the pathogenesis of HSPN.

The role of microRNA-1246 in the regulation of B cell activation and the pathogenesis of systemic lupus erythematosus

Background

The pathogenesis of systemic lupus erythematosus (SLE) has not yet been completely elucidated. One of the hallmarks of SLE is the production of autoantibodies by uncontrolled over-activated B cells. Early B cell factor 1 (EBF1) contributes to the development, activation, and proliferation of B cells through activation of the AKT signaling pathway. Accumulating evidence has demonstrated that several microRNAs (miRNAs) contribute to the pathogenesis of autoimmune diseases through the regulation of B cells in SLE. We aim to investigate the expression patterns of miR-1246 in B cells and its contribution to pathogenesis of SLE.

Results

Our results showed that the expression of miR-1246 was significantly decreased in B cells from SLE patients. We verified that miR-1246 specifically targeted the EBF1 messenger RNA (mRNA) by interacting with its 3′-untranslated region (3′-UTR) and regulated the expression of EBF1. Transfection of miR-1246 inhibitors into healthy B cells upregulated the expression of EBF1, enhanced B cell function, and increased the production of B cell surface co-stimulatory molecules CD40, CD80, and CD86. We also observed that abnormal activation of the AKT signaling pathway was associated with decreased P53 expression, leading to the downregulation of the miR-1246 expression; and upregulation of the miR-1246 expression reversed the responsiveness of B cells by inhibiting EBF1 expression.

Conclusions

Activated B cells in lupus could decrease the expression of miR-1246 through the AKT-P53 signaling pathway, which in turn enhances the expression of EBF1, thereby promoting further activation of B cells. Conversely, upregulation of miR-1246 could interrupt this amplification pathway. Our findings thus provide a theoretical framework towards the research of novel biological targets in SLE treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-015-0063-7) contains supplementary material, which is available to authorized users.