New data were presented at the 15th Conference on Retroviruses and Opportunistic Infections that further support the importance of considering the neuroeffectiveness of antiretroviral drugs when designing treatment regimens. Two studies linked antiretroviral therapy that had estimates of better neuroeffectiveness with better global neuropsychologic outcomes in life. A third study linked estimates of better antiretroviral therapy neuroeffectiveness, particularly nonnucleoside analogue reverse transcriptase inhibitors, with a lower prevalence of HIV-associated brain pathology at death. Additional findings presented at the conference focused on the correlates of HIV-associated neurocognitive disorders (HAND) and peripheral neuropathy. Supporting the concept that viral factors influence the pathogenesis of HAND, high frequencies of HAND were identified in people infected with HIV subtype D and in people infected with subtype B and having brain-specific mutations in V3 of gp160. Supporting the importance of host correlates of HAND, important data from a macaque study identified a strong link between a major histocompatibility complex class I allele, Mane-A*10, and simian immunodeficiency virus encephalitis. Supporting the importance of comorbidities in determining risk for HAND, high levels of lipopolysaccharide in blood, likely derived from the HIV-injured intestine and bacterial translocation, were linked to HAND. Coinfections with JC virus or Treponema pallidum were topics of other presentations, identifying a prognostic marker for PML (better CD8+ cytotoxic T-lymphocyte responses were associated with survival) and a diagnostic one for neurosyphilis (CXCL13 levels in CSF).

The aims of the present study were to assess the concentrations of different cytokines and chemokines in blood serum and cerebrospinal fluid (CSF) samples of patients with Lyme neuroborreliosis and to identify the possible marker(s) that would enable a distinction between clinically evident and suspected Lyme neuroborreliosis, as well as between Lyme neuroborreliosis and tick-borne encephalitis (TBE). Our additional interest was to evaluate the relationship between cytokine and chemokine concentrations and Borrelia burgdorferi sensu lato isolation from CSF, as well as intrathecal synthesis of specific borrelial antibodies. We found that higher concentrations of CXCL13 and lower concentrations of interleukin 10 (IL-10) in serum were associated with higher odds for clinically evident Lyme neuroborreliosis compared to suspected Lyme neuroborreliosis, as well as to TBE. The concentrations of IL-2, IL-5, IL-6, IL-10, and CXCL13 in the CSF were higher in patients with evident Lyme neuroborreliosis than in those who were only suspected to have the disease. A comparison of CSF cytokine and chemokine levels in patients with and without intrathecal synthesis of specific borrelial antibodies revealed that CXCL13 CSF concentration is significantly associated with intrathecal synthesis of borrelial antibodies. A comparison of the cytokine and chemokine CSF concentrations in patients with clinically evident Lyme neuroborreliosis according to CSF culture results revealed that higher concentrations of gamma interferon (IFN-γ) were associated with lower odds of Borrelia isolation. Although several differences in the blood serum and CSF concentrations of various cytokines and chemokines between the groups were found, the distinctive power of the majority of these findings is low. Further research on well-defined groups of patients is needed to appraise the potential diagnostic usefulness of these concentrations.

OBJECTIVE

Systemic lupus erythematosus (SLE) is a prototype of systemic autoimmune disease in which cytokines such as B lymphocyte chemoattractant (BLC) or CXC motif ligand 13 (CXCL13) play an important role as major regulators of B1 and B2 cell trafficking for activation of autoreactive T helper cells. CXCL13 can induce trafficking of the CXCR5+ T lymphocyte subset designated as follicular helper T lymphocytes which are specifically involved in autoantibody production during the development of lupus. Here, we ask whether serum levels of CXCL13 correlate with disease activity and severity and renal involvement in children with SLE.

METHODS

Serum samples from 40 children with SLE and 32 healthy controls were analyzed by ELISA for the concentrations of CXCL13.

RESULTS

Median (interquartile range (IQR) serum CXCL13 concentrations (pg/ml) were increasingly higher across the following groups: healthy controls (71.6 (66.6-81.8), SLE patients with inactive disease (140.8 (99.7-198.8), p = 0.0005 versus controls) and active disease (293.0 (105.5-489.8), p = 0.0001 versus controls) (inactive versus active; p < 0.0001). Concentrations of circulating CXCL13 correlated with SLEDAI (r = 0.499, p = 0.029) and double-stranded DNA titers (r = 0.71, p < 0.001). Moreover, median CXCL13 concentrations were higher in patients with renal involvement (270.6 (150.4-430.7) compared with those without renal involvement (120.6 (70.5-208.9). According to WHO pathological classification of lupus nephritis, median CXCL13 concentrations were higher in children with class III, IV and V nephritis compared with those with class I and II nephritis (333.9 (169.4-491.5) versus (180.4 (107.9-209.7).

CONCLUSIONS

Our data indicate that an increased level of CXCL13 is a feature of SLE that correlates with disease activity and severity. CXCL13 expression in lupus nephritis represents a new pathogenetic mechanism of diagnostic and prognostic significance. The pharmacological regulation of CXCL13 and its receptor, CXCR5, expression may be a useful tool in the therapy of lupus nephritis.

To study aberrant B cell trafficking into the CSF in opsoclonus-myoclonus syndrome (OMS), chemoattractants CXCL13 and CXCL12, and B cell frequency and CXCR5 expression, were evaluated. CSF CXCL13 concentration and the CSF/serum ratio were higher in untreated OMS than controls, related directly to OMS severity and inversely to OMS duration, and correlated with CSF B cell frequency and oligoclonal bands. CXCL12 showed the opposite pattern. Selective accumulation of CXCR5+ memory B cells in CSF was found. In ACTH-treated OMS, CXCL13, but not CXCL12, was lower. These data implicate the chemokine/chemoreceptor pair CXCL13/CXR5 in B cell recruitment to the CNS in OMS. CXCL13 and CXCL12 may serve as reciprocal biomarkers of disease activity, but CXCL13 also had utility as a treatment biomarker.

Ischemic stroke triggers neurogenesis from neural stem/progenitor cells (NSPCs) in the subventricular zone (SVZ) and migration of newly formed neuroblasts toward the damaged striatum where they differentiate to mature neurons. Whether it is the injury per se or the associated inflammation that gives rise to this endogenous neurogenic response is unknown. Here we showed that inflammation without corresponding neuronal loss caused by intrastriatal lipopolysaccharide (LPS) injection leads to striatal neurogenesis in rats comparable to that after a 30 min middle cerebral artery occlusion, as characterized by striatal DCX+ neuroblast recruitment and mature NeuN+/BrdU+ neuron formation. Using global gene expression analysis, changes in several factors that could potentially regulate striatal neurogenesis were identified in microglia sorted from SVZ and striatum of LPS-injected and stroke-subjected rats. Among the upregulated factors, one chemokine, CXCL13, was found to promote neuroblast migration from neonatal mouse SVZ explants in vitro. However, neuroblast migration to the striatum was not affected in constitutive CXCL13 receptor CXCR5(-/-) mice subjected to stroke. Infarct volume and pro-inflammatory M1 microglia/macrophage density were increased in CXCR5(-/-) mice, suggesting that microglia-derived CXCL13, acting through CXCR5, might be involved in neuroprotection following stroke. Our findings raise the possibility that the inflammation accompanying an ischemic insult is the major inducer of striatal neurogenesis after stroke.

We investigated the hypothesis that salivary gland inoculation stimulates formation of ectopic germinal centers (GCs), transforming the gland into a mucosal inductive site. Intraglandular infection of mice with murine cytomegalovirus (MCMV; control: UV-inactivated MCMV) induces salivary gland ectopic follicles comprising cognate interactions between CD4(+) and B220(+) lymphocytes, IgM(+) and isotype-switched IgG(+) and IgA(+) B cells, antigen presenting cells, and follicular dendritic cells. B cells coexpressed the GC markers GCT (57%) and GL7 (52%), and bound the lectin peanut agglutinin. Lymphoid follicles were characterized by a 2- to 3-fold increase in mRNA for CXCL13 (lymphoid neogenesis), syndecan-1 (plasma cells), Blimp-1 (plasma cell development/differentiation), and a 2- to 6-fold increase for activation-induced cytidine deaminase, PAX5, and the nonexcised rearranged DNA of an IgA class-switch event, supporting somatic hypermutation and class-switch recombination within the salivary follicles. Intraglandular inoculation also provided protection against a systemic MCMV challenge, as evidenced by decreased viral titers (10(5) plaque-forming units to undetectable), and restoration of normal salivary flow rates from a 6-fold decrease. Therefore, these features suggest that the salivary gland participates in oral mucosal immunity via generation of ectopic GCs, which function as ectopic mucosal inductive sites.

OBJECTIVE

Based on the newly recognized role of the homeostatic chemokines in inflammation, we hypothesized that CXCL13 could modulate atherogenesis and plaque destabilization.

METHODS

The study included in vivo analyses in patients with carotid atherosclerosis and in vitro experiments in cells involved in atherogenesis (ie, monocytes/macrophages, vascular smooth muscle cells [SMC], and platelets).

RESULTS

Our main findings were: (i) Patients with carotid atherosclerosis (n = 130) had increased plasma levels of CXCL13 with particularly high levels in symptomatic disease. (ii) CXCL13 showed increased expression within atherosclerotic carotid plaques as compared with non-atherosclerotic vessels. (iii) Within the atherosclerotic lesions, CXCR5 and CXCL13 were expressed by macrophages and SMC in all stages of plaque progression. (iv) Releasate from activated platelets and toll-like receptor activation enhanced the expression of CXCL13 in THP-1 monocytes and primary monocytes. (v) In vitro, CXCL13 exerted anti-apoptotic effects in primary monocytes, THP-1 macrophages, and vascular SMC. (vi) CXCL13 increased arginase-1, transforming growth factor-β, and interleukin-10 expression in THP-1 cells and in samples from isolated carotid plaques.

CONCLUSIONS

Levels of CXCL13 are increased in carotid atherosclerosis both systemically and within the atherosclerotic lesion. Based on our in vitro findings, we hypothesize a potential plaque stabilizing effects of CXCL13-CXCR5 interaction.

Treatment of patients with rheumatoid arthritis (RA) is rarely personalized, since predictors of disease course are lacking. The severity of RA can be measured objectively by radiographic progression. The most reliable way to measure radiographic progression is in a longitudinal cohort with serial time points, scoring on a quantitative scale, with a validated scoring method and trained readers. Current models used to predict radiographic progression are based on C-reactive protein and anti-citrullinated protein antibodies. Other biomarkers could increase the prognostic ability of these models. In this review, we evaluated the published (and partly nonpublished) data on genetic, serologic, and imaging biomarkers for the severity of joint destruction in RA. We evaluated variants in 10 genes (CD40, IL2RA, IL4R, IL15, OPG, DKK1, SOST, GRZB, MMP9, and SPAG16). In 5 variants (IL2RA, DKK1, GRZB, MMP9, and SPAG16), we found evidence of an association at the functional level. We evaluated several serological biomarkers, namely, autoantibodies (RF, ACPA, anti-CarP), markers related to inflammation (ESR, CRP), and proteinases or components of the extracellular matrix of bone and cartilage (MMP3, CTX-I, CTX-II, COMP, TIMP1, PYD, RANKL/OPG, CXCL13). Finally, we evaluated markers that can be visualized by ultrasound or MRI, including erosions, bone marrow edema, synovitis, and tenosynovitis. Several studies showed that bone marrow edema and synovitis on MRI are robust predictors of radiographic progression. Some studies showed that inflammation detected with ultrasound predicted radiographic progression. Future studies will reveal whether adding and combining all these different biomarkers will increase the accuracy of risk models predicting radiographic progression in RA.

Placental infection with Plasmodium falciparum is associated with increased levels of proinflammatory cytokines, including tumor necrosis factor alpha (TNF-α) and gamma interferon (IFN-γ), and previous studies have associated increased levels of these cytokines with low birth weight (LBW), especially for malaria-infected primigravidae. To define the contribution of TNF-α and IFN-γ networks to placental-malaria-associated LBW, we measured chemokines induced by TNF-α and IFN-γ and related them to birth weight in a birth cohort of 782 mother-infant pairs residing in an area of P. falciparum holoendemicity in Tanzania. Among primigravidae, levels of CCL2, CXC ligand 9 (CXCL9), and CXCL13 were significantly higher during malaria infection in both the placenta and peripheral blood. Placental CXCL9 and CXCL13 levels were also higher in placental blood from secundigravidae and multigravidae. In multivariate analyses adjusted for known predictors of birth weight, malaria-infected primigravidae with placental CXCL9 levels in the lowest tertile gave birth to babies who weighed 610 g more than babies born to mothers with high CXCL9 levels. CXCL9 expression is induced by IFN-γ, and the strong association between birth weight and placental CXCL9 is consistent with previous observations relating IFN-γ to poor pregnancy outcomes.

BACKGROUND

Pateclizumab (MLTA3698A) is a humanized mAb against lymphotoxin α (LTα), a transiently expressed cytokine on activated B and T cells (Th1, Th17), which are implicated in rheumatoid arthritis (RA) pathogenesis. This study was conducted to assess the safety, tolerability, < NOTE: For clarity and per AMA/S-W Style, please restore the use of Oxford/serial commas (ie: David likes vanilla, strawberry, and chocolate ice cream) throughout. and biologic activity of single and multiple doses of intravenous (IV) or subcutaneous (SC) pateclizumab in RA patients.

METHODS

The single ascending dose (SAD) phase in patients with stable RA consisted of six cohorts (4:1 active:placebo at 0.3 mg/kg IV, 1.0 mg/kg IV, 1.0 mg/kg SC, 3.0 mg/kg IV, 3.0 mg/kg SC, and 5.0 mg/kg IV; n = 5/cohort). In the multiple ascending dose (MAD) phase, patients with prespecified RA disease activity received three doses of pateclizumab or placebo (4:1) every 2 weeks (1.0 mg/kg SC, n = 10; 3.0 mg/kg SC, n = 20; or 5.0 mg/kg IV, n = 5). Safety and tolerability were assessed throughout, and clinical activity was determined after three doses (Week 6).

RESULTS

We observed no serious adverse events (AEs) or dose-limiting toxicities, and the majority of AEs were mild to moderate. The pharmacokinetic profiles were linear, and clearance was independent of dose. Reductions in levels of serum CXCL13 were observed, supporting the biologic activity of pateclizumab on the LTα pathway. Patients receiving pateclizumab in the 3.0 mg/kg MAD group (3.0 mg/kg SC) demonstrated ACR20, ACR50, and ACR70 response rates at week 6 of 75%, 56% and 25%, respectively, compared with 57%, 29%, and 0% in the placebo group. The median Disease Activity Score in 28 joints, C-reactive protein, reduction was 28% for pateclizumab, versus 8.4% for placebo.

CONCLUSIONS

Pateclizumabwas generally well-tolerated in RA patients. Preliminary evidence of clinical activity was observed in active RA patients at the dose level targeted for clinical effect.

The definitive diagnosis of acute neuroborreliosis (NB) is based upon the presence of lymphomonocytic CSF pleocytosis and intrathecal Borrelia burgdorferi (B.b.)-specific antibody production (expressed by an antibody index of >2). However, the latter might be absent in early stages of the disease. Now a recently discovered additional CSF marker-the cytokine CXCL13-was found to be positive in every initial CSF sample from patients with NB and therefore could be a valuable tool for early diagnosis and initiation of antibiotic therapy. We report an unusual case of NB in a patient with a history of metastatic carcinoma of the prostate and unilateral polyradiculitis. While no intrathecal B.b.-specific antibody production could be demonstrated initially, the CSF CXCL13 level was high (>500 ng/g vs <1.7 ng/g in healthy controls). During the course of the disease, the antibody index turned positive (4.8) and the patient responded to antibiotic therapy, thus confirming the diagnosis. In this case, measuring CXCL13 in the CSF would have led to earlier diagnosis and treatment of NB.

Clinical studies using prognostic and predictive signatures have shown that an immune signal emanating from whole tumors reflects the level of immune cell infiltration--a high immune signal linked to improved outcome. Factors regulating immune cell trafficking to the tumor, however, are not known. Previous work has shown that expression of interferon regulatory factor 5 (IRF5), a critical immune regulator, is lost in ~80% of invasive ductal carcinomas examined. We postulated that IRF5-positive and -negative breast tumors would differentially regulate immune cell trafficking to the tumor. Using a focused tumor inflammatory array, differences in cytokine and chemokine expression were examined between IRF5-positive and -negative MDA-MB-231 cells grown in three-dimensional culture. A number of cytokines/chemokines were found to be dysregulated between cultures. CXCL13 was identified as a direct target of IRF5 resulting in the enhanced recruitment of B and T cells to IRF5-positive tumor-conditioned media. The ability of IRF5 to regulate mediators of cell migration was confirmed by enzyme-linked immunosorbent assay, chromatin immunoprecipitation assay, small interfering RNA knockdown and immunofluorescence staining of human breast tumor tissues. Analysis of primary immune cell subsets revealed that IRF5 specifically recruits CXCR5(+) B and T cells to the tumor; CXCR5 is the receptor for CXCL13. Analysis of primary breast tumor tissues revealed a significant correlation between IRF5 and CXCL13 expression providing clinical relevance to the study. Together, these data support that IRF5 directly regulates a network of genes that shapes a tumor immune response and may, in combination with CXCL13, serve as a novel prognostic marker for antitumor immunity.

BACKGROUND

Tumor necrosis factor (TNF) and, possibly, lymphotoxin alpha (LTα) signaling contribute to inflammation and rheumatoid arthritis (RA) pathogenesis. Pateclizumab (anti-lymphotoxin- alpha; MLTA3698A) is a humanized monoclonal antibody that blocks and depletes anti-LTα. This phase 2, randomized, head-to-head, active- and placebo-controlled trial examined the safety and efficacy of pateclizumab compared to adalimumab in RA patients with an inadequate response to disease-modifying antirheumatic drugs (DMARD-IR).

METHODS

Patients (n = 214) with active RA (≥ 6 swollen and tender joints, C-reactive protein ≥ 10 mg/L) on oral DMARDs were randomized (2:2:1) to receive pateclizumab 360 mg, adalimumab 40 mg, or placebo subcutaneously every 2 weeks. The primary endpoint, 4-variable, 28-joint disease activity score erythrocyte sedimentation rate (DAS28(4)-ESR) response, was evaluated at 12 weeks using an analysis of covariance (ANCOVA) model with adjustments for concomitant DMARD use and geographic region. Secondary efficacy endpoints included American College of Rheumatology (ACR) 20, ACR50, and ACR70 responses at Day 85. Pharmacokinetics, pharmacodynamics, and immunogenicity of pateclizumab were assessed.

RESULTS

Pateclizumab reduced the DAS28(4)-ESR response (-1.89) at 12 weeks, however, this did not reach statistical significance compared to placebo (-1.54), while adalimumab (-2.52) differed significantly from both placebo and pateclizumab. Pateclizumab 12-week ACR20, ACR50 and ACR70 response rates (64%, 33%, and 14%) suggested clinical activity but were not statistically significant compared to placebo rates (46%, 24%, and 8%, respectively). CXCL13 serum levels decreased significantly following pateclizumab and adalimumab administration, demonstrating pharmacological target engagement by both drugs. Overall, adverse events (AEs) were comparable among all cohorts. Infections were the most common AE, occurring with comparable frequency in all groups. Serious AEs occurred in 0% of pateclizumab, 5.9% of adalimumab, and 2.3% of placebo patients, with serious infection in 2.3% of adalimumab patients and none in pateclizumab and placebo patients.

CONCLUSIONS

Pateclizumab had a good safety profile in patients inadequately responsive to DMARDs, but no statistically significant improvement in RA signs and symptoms after 12 weeks of treatment. Adalimumab demonstrated efficacy and safety comparable to published results in this head-to-head comparison in DMARD-IR RA patients.

BACKGROUND

ClinicalTrials.gov NCT01225393, Registered 18 October 2010.

Sjögren's syndrome (SS) is a debilitating autoimmune disease. Patients with SS may develop xerostomia. This process is progressive, and there are no therapeutics that target disease etiology. We hypothesized BAFF receptor (BAFFR) blockade would mitigate SS disease development, and neutralization of CXCL13 and BAFF signaling would be more efficacious than BAFFR blockade alone. We treated NOD/ShiLtJ SS mice with soluble BAFF receptor (BAFFR-Fc) or anti-CXCL13/BAFFR-Fc in combination, prior to the development of clinical disease. Our results show treatment with BAFFR-Fc reduced peripheral B cell numbers and decreased sialadenitis. In addition, this treatment reduced total serum immunoglobulin as well as IgG and IgM specific anti-nuclear autoantibodies. NOD/ShiLtJ mice treated with BAFFR-Fc and anti-CXCL13 antibody were protected from salivary deficits. Results from this study suggest blockade of CXCL13 and BAFFR together may be an effective therapeutic strategy in preventing salivary hypofunction and reducing autoantibody titers and sialadenitis in patients with SS.

Resolution of inflammation is critical to restoration of tissue function after an inflammatory response. We previously demonstrated that 12/15-lipoxygenase (12/15-LOX)-expressing eosinophils contribute to this process in murine zymosan-induced peritonitis. In this study, eosinophils promoted resolution by regulating expression of macrophage CXCL13. Microarray analysis revealed that eosinophils significantly increased (∼3-fold) the expression of macrophage CXCL13 by a 12/15-LOX-dependent mechanism. CXCL13 depletion caused a resolution defect, with the reduced appearance of phagocytes carrying engulfed zymosan in the draining lymph nodes. Inflamed lymph node hypertrophy, a critical feature of the resolution process, was reduced by ∼60% in eosinophil-deficient mice, and adoptive transfer of eosinophils or administration of CXCL13 corrected this defect. Administration of the 12/15-LOX-derived mediator lipoxin A4 (LXA4) increased the expression of CXCL13 and restored the defect of lymph node hypertrophy in eosinophil-deficient mice. These results demonstrate that eosinophils control the resolution of inflammation and draining lymph node hypertrophy through proresolving lipid mediators and the CXCL13 pathway in mice.

Tick-borne relapsing fever (RF) and Lyme disease (LD) are spirochetal infections of humans caused by different Borrelia species in endemic areas throughout the world. Our laboratory is studying the response of mammalian hosts to borrelia infection in RF and LD. For this, we use mice and non-human primates infected with B. burgdorferi sensu stricto strain N40 (N40) and the Oz1 strain of Borrelia turicatae (Bt), agents of LD and RF in North America, respectively. Our results have revealed that outbred non-human primates are significantly less susceptible than outbred mice to persistent infection with N40. In contrast, the majority of mice inoculated with the RF agent B. turicatae clear the infection, with the notable exception of residual brain or blood infection in up to 25% of cases. Little if any tissue injury occurs in immunocompetent animals with either LD or RF. In contrast, impairment of specific antibody production results in significant tissue injury, most notably in the heart, in both LD and RF. The inflammatory infiltrate is rich in plasma cells, activated macrophages and T cells, and there is significant deposition of antibody and complement, including membrane attack complex, in inflamed tissues and spirochetes. Significant loss of cardiomyocytes with apoptosis and caspase activation was observed in the heart of immunosuppressed non-human primates infected with N40 and in B cell-deficient mice infected with B. turicatae. Unlike the heart, the brain of B cell-deficient mice infected with B. turicatae showed prominent microglial activation but no detectable tissue injury. Tissues from immunosuppressed non-human primates infected with N40 produce large amounts of immunoglobulin and the B cell chemokine CXCL13, both of which significantly correlate with the spirochetal load. We conclude that the main response of mammalian hosts in LD and RF is the production of specific antibody to clear the infection. Failure of this response leads to persistent infection, which can lead to tissue injury, most notably in the heart.

Background: Recent findings indicated that SARS-CoV-2 related neurological manifestations involve cytokine release syndrome along with endothelial activation, blood brain barrier dysfunction, and immune-mediated mechanisms. Very few studies have fully investigated the CSF correlates of SARS-CoV-2 encephalitis.

Methods: Patients with PCR-confirmed SARS-CoV-2 infection and encephalitis (COV-Enc), encephalitis without SARS-CoV-2 infection (ENC) and healthy controls (HC) underwent an extended panel of CSF neuronal (NfL, T-tau), glial (GFAP, TREM2, YKL-40) and inflammatory biomarkers (IL-1β, IL-6, Il-8, TNF- α, CXCL-13 and β2-microglobulin).

Results: Thirteen COV-Enc, 21 ENC and 18 HC entered the study. In COV-Enc cases, CSF was negative for SARS-CoV-2 real-time PCR but exhibited increased IL-8 levels independently from presence of pleocytosis/hyperproteinorracchia. COV-Enc patients showed increased IL-6, TNF- α, and β2-microglobulin and glial markers (GFAP, sTREM-2, YKL-40) levels similar to ENC but normal CXCL13 levels. Neuronal markers NfL and T-Tau were abnormal only in severe cases.

Conclusions: SARS-CoV-2-related encephalitis were associated with prominent glial activation and neuroinflammatory markers, whereas neuronal markers were increased in severe cases only. The pattern of CSF alterations suggested a cytokine-release syndrome as the main inflammatory mechanism of SARS-CoV-2 related encephalitis.

Keywords: COVID-19; Cytokine storm syndrome; Encephalitis; ICANS; SARS-CoV-2.

The molecular basis to autoimmune arthritis is unclear. To identify candidate molecules that may be involved in the development and progression of collagen-induced arthritis (CIA), an animal model for human rheumatoid arthritis, we used microarray and real-time PCR assays to examine the gene expression profiles at the onset, peak and decline phase of CIA. Our results showed that, of the 514 immune-related genes assayed in microarrays, fifty-eight genes showed differential expression with thirty-one up-regulated and twenty-seven down-regulated in CIA joints, in comparison to normal joint tissue. By real-time PCR, expression of some chemokines/chemokine receptors, such as CCR1, CXCR4, CXCL13 and MCP1, showed significantly elevated in the inflamed joints. Quite a few genes were significantly up- or down-regulated at the peak time point, which indicates their roles in the progression of the disease. In addition, the expression levels of some genes remained significantly elevated at all stages of the disease. These gene expression profiles may help understand the pathogenesis of the disease.

Tertiary lymphoid tissue (TLT) is lymphoid tissue that forms in adult life as a result of chronic inflammation in a tissue or organ. TLT has been shown to form in a variety of chronic inflammatory diseases, though it is not clear if and how TLT develops in the inflamed colon during inflammatory bowel disease. Here, we show that TLT develops as newly formed lymphoid tissue in the colon following dextran sulphate sodium induced colitis in C57BL/6 mice, where it can be distinguished from the preexisting colonic patches and solitary intestinal lymphoid tissue. TLT in the inflamed colon develops following the expression of lymphoid tissue-inducing chemokines and adhesion molecules, such as CXCL13 and VCAM-1, respectively, which are produced by stromal organizer cells. Surprisingly, this process of TLT formation was independent of the lymphotoxin signaling pathway, but rather under neuronal control, as we demonstrate that selective surgical ablation of vagus nerve innervation inhibits CXCL13 expression and abrogates TLT formation without affecting colitis. Sympathetic neuron denervation does not affect TLT formation. Hence, we reveal that inflammation in the colon induces the formation of TLT, which is controlled by innervation through the vagus nerve.

There is a need to develop improved methods to treat and potentially cure HIV infection. During chronic HIV infection, replication is concentrated within T follicular helper cells (Tfh) located within B cell follicles, where low levels of virus-specific CTL permit ongoing viral replication. We previously showed that elevated levels of simian immunodeficiency virus (SIV)-specific CTL in B cell follicles are linked to both decreased levels of viral replication in follicles and decreased plasma viral loads. These findings provide the rationale to develop a strategy for targeting follicular viral-producing (Tfh) cells using antiviral chimeric antigen receptor (CAR) T cells co-expressing the follicular homing chemokine receptor CXCR5. We hypothesize that antiviral CAR/CXCR5-expressing T cells, when infused into an SIV-infected animal or an HIV-infected individual, will home to B cell follicles, suppress viral replication, and lead to long-term durable remission of SIV and HIV. To begin to test this hypothesis, we engineered gammaretroviral transduction vectors for co-expression of a bispecific anti-SIV CAR and rhesus macaque CXCR5. Viral suppression by CAR/CXCR5-transduced T cells was measured in vitro, and CXCR5-mediated migration was evaluated using both an in vitro transwell migration assay, as well as a novel ex vivo tissue migration assay. The functionality of the CAR/CXCR5 T cells was demonstrated through their potent suppression of SIVmac239 and SIVE660 replication in in vitro and migration to the ligand CXCL13 in vitro, and concentration in B cell follicles in tissues ex vivo. These novel antiviral immunotherapy products have the potential to provide long-term durable remission (functional cure) of HIV and SIV infections.

Serum anti-citrullinated peptide antibodies (ACPAs) may be present before the development of rheumatoid arthritis (RA) and may be predictive of more severe, erosive disease. This study was undertaken to examine the synovial tissue immunophenotype according to ACPA status in patients with RA, as well as the response to treatment and erosion status.

Consecutive RA patients were prospectively recruited and underwent clinical and serologic assessments before and after treatment. Radiologic assessment was performed at the time of clinical follow-up. Synovial tissue was immunostained for specific markers of B cells (CD19), T cells (CD3, CD4, and CD8), macrophages (CD68), and blood vessels (factor VIII). Serum CXCL13 levels were quantified by enzyme-linked immunosorbent assay. Synovial tissue sections were analyzed for immunophenotype according to ACPA status, using a validated semiquantitative scoring method, and also analyzed for the presence of lymphoid aggregates. Response to treatment with nonbiologic or biologic disease-modifying antirheumatic drugs was assessed using the European League Against Rheumatism (EULAR) response criteria.

In total, 123 subjects (78 ACPA+) were included. Compared to ACPA- RA patients, synovium from ACPA+ RA patients was characterized by significantly higher levels of CD19+ B cells and CD3+ and CD8+ T cells (each P < 0.05), and CD19+ B cell levels were significantly higher in patients who were naive to treatment. The CD19+ B cell infiltrate level was higher in patients with erosions at follow-up (P = 0.0128). Levels of lymphoid aggregates of CD19+ B cells were significantly higher in ACPA+ patients (P < 0.05), and this was associated with increased serum CXCL13 levels. The EULAR response was significantly associated with the level of CD3+ T cell infiltrates (P < 0.05), while CD68+ macrophage and CD8+ T cell levels were predictive of the response to tumor necrosis factor inhibitors (P < 0.05).

The results of this prospective study demonstrate that the levels of synovial B cell infiltrates and lymphoid aggregates were significantly higher in ACPA+ RA patients, especially those who were naive to treatment. In addition, ACPA+ subjects developed more erosions during progression of the disease and had higher serum levels of CXCL13. The EULAR response to therapy in ACPA+ RA patients was associated with increased levels of T cell and macrophage markers.

We previously reported that sphingosine 1-phosphate (S1P) regulates peritoneal B-cell trafficking and subsequent intestinal IgA production, but the underlying mechanisms remain obscure. We demonstrate here that nuclear factor kappaB-inducing kinase (NIK) is involved in the regulation of S1P-mediated trafficking of peritoneal B cells. Although peritoneal B cells from NIK-mutated alymphoplasia (aly) mice expressed type 1 S1P receptor (S1P(1)) at comparable levels and demonstrated normal migration toward S1P, aly peritoneal B cells showed decreased sensitivity to FTY720, an S1P(1) modulator. NIK-mutated stromal cells showed decreased levels of adhesion molecules (VCAM-1 and ICAM-1) and increased CXCL13 expressions, leading to impaired ability to support S1P-mediated emigration, but not immigration, of peritoneal B cells. Therefore, aly peritoneal B cells exhibited normal S1P-mediated peritoneal B-cell trafficking from peritoneum to intestine for IgA production when they were transferred into severe combined immunodeficient or wild-type mice. However, S1P-mediated emigration of wild-type B cells from the aly peritoneal cavity was impaired without affecting their immigration from the blood. Further, transfer of wild-type stromal cells into the peritoneum restored S1P-mediated trafficking of aly peritoneal B cells. These findings suggest that NIK in stromal cells has a specific role in the regulation of S1P-mediated trafficking of peritoneal B cells.

Myeloid-derived suppressor cells (MDSCs) expand in tumor-bearing host. They suppress anti-tumor immune response and promote tumor growth. Chemokines play a vital role in recruiting MDSCs into tumor tissue. They can also induce the generation of MDSCs in the bone marrow, maintain their suppressive activity, and promote their proliferation and differentiation. Here, we review CCL2/CCL12-CCR2, CCL3/4/5-CCR5, CCL15-CCR1, CX3CL1/CCL26-CX3CR1, CXCL5/2/1-CXCR2, CXCL8-CXCR1/2, CCL21-CCR7, CXCL13-CXCR5 signaling pathways, their role in MDSCs recruitment to tumor tissue, and their correlation with tumor development, metastasis and prognosis. Targeting chemokines and their receptors may serve as a promising strategy in immunotherapy, especially combined with other strategies such as chemotherapy, cyclin-dependent kinase or immune checkpoints inhibitors.

BACKGROUND

There is a need for clinically useful biomarkers of disease activity in clinically isolated syndrome (CIS) and relapsing remitting MS (RRMS). The aim of this study was to assess the correlation between neurofilament light chain (NFL) in cerebrospinal fluid (CSF) and serum and the relationship between NFL and other biomarkers, subsequent disease activity, and brain volume loss in CIS and RRMS.

METHODS

A panel of neurodegenerative and neuroinflammatory markers were analyzed in repeated CSF samples from 41 patients with CIS or RRMS in a prospective longitudinal cohort study and from 22 healthy controls. NFL in serum was analyzed using a single-molecule array (Simoa) method. "No evidence of disease activity-3" (NEDA-3) status and brain volume (brain parenchymal fraction calculated using SyMRI®) were recorded during 4 years of follow-up.

RESULTS

NFL levels in CSF and serum correlated significantly (all samples, n = 63, r 0.74, p < 0.001), but CSF-NFL showed an overall stronger association profile with NEDA-3 status, new T2 lesions, and brain volume loss. CSF-NFL was associated with both new T2 lesions and brain volume loss during follow-up, whereas CSF-CHI3L1 was associated mainly with brain volume loss and CXCL1, CXCL10, CXCL13, CCL22, and MMP-9 were associated mainly with new T2 lesions.

CONCLUSIONS

Serum and CSF levels of NFL correlate, but CSF-NFL predicts and reflects disease activity better than S-NFL. CSF-NFL levels are associated with both new T2 lesions and brain volume loss. Our findings further add to the accumulating evidence that CSF-NFL is a clinically useful biomarker in CIS and RRMS and should be considered in the expanding NEDA concept. CSF-CXCL10 and CSF-CSF-CHI3L1 are potential markers of disease activity and brain volume loss, respectively.