Intravenous immunoglobulin promotes the proliferation of CD4+CD25+ Foxp3+ regulatory T cells and the cytokines secretion in patients with Guillain-Barré syndrome in vitro

Causal relationship between immune cells and Guillain-Barré syndrome: a Mendelian randomization study

Objective

The aim of this study was to investigate the causal effect of immune cell phenotype on GBS using two-sample Mendelian randomization (MR) approach.

Methods

This study used MR to investigate the causal relationship between 731 immune cell phenotypes and GBS. We used Inverse variance weighted, Weighted median, MR Egger, Simple mode, Weighted mode for MR analysis. We also used the Cochran Q test, MR-Egger intercept test, IVW regression and MR-PRESSO, leave-one-out analysis to assess the presence of horizontal pleiotropy, heterogeneity and stability, respectively.

Results

Our study revealed a causal relationship between 33 immune cell phenotypes and GBS. Twenty immunophenotypes were observed to be associated with GBS as risk factors. For example, CD20 on IgD+ CD38dim in the B cell group (OR = 1.313, 95%CI:1.042-1.654, p = 0.021), CD3 on CD4 Treg in Treg cell group (OR = 1.395, 95%CI:1.069-1.819, p = 0.014), CD3 on TD CD8br in Maturation stages of T cell group (OR = 1.486, 95%CI:1.025-2.154, p = 0.037), CD16 on CD14+ CD16+ monocyte in Monocyte group (OR = 1.285, 95%CI:1.018-1.621, p = 0.035), CD33dim HLA DR+ CD11b + %CD33dim HLA DR+ in Myeloid cell group (OR = 1.262, 95%CI:1.020-1.561, p = 0.032), HLA DR+ NK AC in TBNK cell group (OR = 1.568, 95%CI:1.100-2.237, p = 0.013). Thirteen immune phenotypes are associated with GBS as protective factors. For example, CD19 on PB/PC in the B cell group (OR = 0.577, 95%CI:0.370-0.902, p = 0.016), CD4 Treg AC in Treg cell group (OR = 0.727, 95%CI:0.538-0.983, p = 0.038), CD11c + monocyte %monocyte in cDC group (OR = 0.704, 95%CI:0.514-0.966, p = 0.030), CX3CR1 on CD14+ CD16- monocyte in Monocyte group (OR = 0.717, 95%CI:0.548-0.939, p = 0.016), Mo MDSC AC in Myeloid cell group (OR = 0.763, 95%CI:0.619-0.939, p = 0.011), CD45 on granulocyte in TBNK group (OR = 0.621, 95%CI:0.391-0.984, p = 0.042).

Conclusion

The findings suggest that certain specific immune cell phenotypes, particularly B cell and Treg cell subpopulations, are causally associated with GBS, providing potential targets for the clinical treatment of GBS.

Genetically predicted N-Acetyl-L-Alanine mediates the association between CD3 on activated and secreting Tregs and Guillain-Barre syndrome

Objective

This study sought to explore the potential causal relationships among immune cell traits, Guillain-Barre syndrome (GBS) and metabolites.

Methods

Employing a two-sample Mendelian randomization (MR) approach, the study investigated the causal associations between 731 immune cell traits, 1400 metabolite levels and GBS leveraging summary-level data from a genome-wide association study (GWAS). To ensure the reliability of our findings, we further assessed horizontal pleiotropy and heterogeneity and evaluated the stability of MR results using the Leave-one-out method.

Results

This study revealed a causal relationship between CD3 on activated & secreting Tregs and GBS. Higher CD3 on activated and secreting Regulatory Tregs increased the risk of GBS (primary MR analysis odds ratio (OR) 1.31/SD increase, 95% confidence interval (CI) 1.08-1.58, p = 0.005). There was no reverse causality for GBS on CD3 on activated & secreting Tregs (p = 0.36). Plasma metabolite N-Acetyl-L-Alanine (ALA) was significantly positively correlated with GBS by using the IVW method (OR = 2.04, 95% CI, 1.26-3.30; p = 0.00038). CD3 on activated & secreting Tregs was found to be positively associated with ALA risk (IVW method, OR, 1.04; [95% CI, 1.01-1.07], p = 0.0078). Mediation MR analysis indicated the mediated proportion of CD3 on activated & secreting Tregs mediated by ALA was 10% (95%CI 2.63%, 17.4%).

Conclusion

In conclusion, our study identified a causal relationship between the level of CD3 on activated & secreting Tregs and GBS by genetic means, with a considerable proportion of the effect mediated by ALA. In clinical practice, thus providing guidance for future clinical research.

VX-509 (Decernotinib)-modified tolerogenic dendritic cells alleviate experimental autoimmune neuritis by promoting Th17/Treg rebalance

BACKGROUND

Guillain-Barré syndrome (GBS) is an auto-inflammatory peripheral nerve disease. Dendritic cell-mediated T cell polarization is of pivotal importance in demyelinating lesions of peripheral nerves and nerve roots. However, the regulatory function of VX-509 (Decernotinib)-modified tolerogenic dendritic cells (VX-509-tolDCs) during immune remodeling following GBS remains unclear. Here, we used experimental autoimmune neuritis (EAN) as a model to investigate these aspects of GBS.

METHODS

DCs were treated with varying concentrations of VX-509 (0.25, 1, and 4 μM) or served as a control using 10-8 M 1,25-(OH)2D3. Flow cytometry was employed to assess the apoptosis, phenotype, and capacity to induce T cell responses of the treated DCs. In the in vivo experiments, EAN mice received administration of VX-509-tolDCs or 1,25-(OH)2D3-tolDCs via the tail vein at a dose of 1x106 cells/mouse on days 5, 9, 13, and 17.

RESULTS

VX-509 inhibited the maturation of DCs and promoted the development of tolDCs. The function of antigen-specific CD4 + T cells ex vivo was influenced by VX-509-tolDCs. Furthermore, the adoptive transfer of VX-509-tolDCs effectively alleviated inflammatory demyelinating lesions in EAN by promoting Th17/Treg (T helper 17 and regulatory T cells) rebalance.

CONCLUSION

The adoptive transfer of VX-509-tolDCs alleviated inflammatory demyelinating lesions in a mouse model of GBS, known as the EAN mouse, by partially restoring the balance between Treg and Th17 cells.

Restoring immune balance with Tregitopes: A new approach to treating immunological disorders

The induction of immunological tolerance is a promising strategy for managing autoimmune diseases, allergies, and transplant rejection. Tregitopes, a class of peptides, have emerged as potential agents for this purpose. They activate regulatory T cells, which are pivotal in reducing inflammation and promoting tolerance, by binding to MHC II molecules and facilitating their processing and presentation to Treg cells, thereby encouraging their proliferation. Moreover, Tregitopes influence the phenotype of antigen-presenting cells by attenuating the expression of CD80, CD86, and MHC class II while enhancing ILT3, resulting in the inhibition of NF-kappa B signaling pathways. Various techniques, including in vitro and in silico methods, are applied to identify Tregitope candidates. Currently, Tregitopes play a vital role in balancing immune activation and tolerance in clinical applications such as Pompe disease, diabetes-related antigens, and the prevention of spontaneous abortions in autoimmune diseases. Similarly, Tregitopes can induce antigen-specific regulatory T cells. Their anti-inflammatory effects are significant in conditions such as autoimmune encephalomyelitis, inflammatory bowel disease, and Guillain-Barré syndrome. Additionally, Tregitopes have been leveraged to enhance vaccine design and efficacy. Recent advancements in understanding the potential benefits and drawbacks of IVIG and the discovery of the function and mechanism of Tregitopes have introduced Tregitopes as a popular option for immune system modulation. It is expected that they will bring about a significant revolution in the management and treatment of autoimmune and immunological diseases. This article is a comprehensive review of Tregitopes, concluding with the potential of these epitopes as a therapeutic avenue for immunological disorders.

Autism spectrum disorder and a possible role of anti-inflammatory treatments: experience in the pediatric allergy/immunology clinic

Autism spectrum disorder (ASD1) is a behaviorally defined syndrome encompassing a markedly heterogeneous patient population. Many ASD subjects fail to respond to the 1st line behavioral and pharmacological interventions, leaving parents to seek out other treatment options. Evidence supports that neuroinflammation plays a role in ASD pathogenesis. However, the underlying mechanisms likely vary for each ASD patient, influenced by genetic, epigenetic, and environmental factors. Although anti-inflammatory treatment measures, mainly based on metabolic changes and oxidative stress, have provided promising results in some ASD subjects, the use of such measures requires the careful selection of ASD subjects based on clinical and laboratory findings. Recent progress in neuroscience and molecular immunology has made it possible to allow re-purposing of currently available anti-inflammatory medications, used for autoimmune and other chronic inflammatory conditions, as treatment options for ASD subjects. On the other hand, emerging anti-inflammatory medications, including biologic and gate-keeper blockers, exert powerful anti-inflammatory effects on specific mediators or signaling pathways. It will require both a keen understanding of the mechanisms of action of such agents and the careful selection of ASD patients suitable for each treatment. This review will attempt to summarize the use of anti-inflammatory agents already used in targeting ASD patients, and then emerging anti-inflammatory measures applicable for ASD subjects based on scientific rationale and clinical trial data, if available. In our experience, some ASD patients were treated under diagnoses of autoimmune/autoinflammatory conditions and/or post-infectious neuroinflammation. However, there are little clinical trial data specifically for ASD subjects. Therefore, these emerging immunomodulating agents for potential use for ASD subjects will be discussed based on preclinical data, case reports, or data generated in patients with other medical conditions. This review will hopefully highlight the expanding scope of immunomodulating agents for treating neuroinflammation in ASD subjects.

Intravenous Immunoglobulin: Mechanism of Action in Autoimmune and Inflammatory Conditions

Intravenous immunoglobulin (IVIG) is the mainstay of therapy for humoral immune deficiencies and numerous inflammatory disorders. Although the use of IVIG may be supplanted by several targeted therapies to cytokines, the ability of polyclonal normal IgG to act as an effector molecule as well as a regulatory molecule is a clear example of the polyfunctionality of IVIG. This article will address the mechanism of action of IVIG in a number of important conditions that are otherwise resistant to treatment. In this commentary, we will highlight mechanistic studies that shed light on the action of IVIG. This will be approached by identifying effects that are both common and disease-specific, targeting actions that have been demonstrated on cells and processes that represent both innate and adaptive immune responses.

Plasma exchange (PE) versus intravenous immunoglobulin (IVIG) for the treatment of Guillain-Barré syndrome (GBS) in patients with severe symptoms: A systematic review and meta-analysis

Background and purpose

Guillain- Barré syndrome (GBS) is a neuropathic condition that leads to the rapid development of impairments and is characterized by weakness and numbness or tingling sensation in the legs and arms and sometimes loss of movement and feeling in the legs, arms, upper body, and face. Currently, the cure for the disease is yet to be developed. However, treatment options such as intravenous immunoglobulin (IVIG) and plasma exchange (PE) have been used to minimize the symptoms and duration of the disease. Therefore, this systematic review and meta-analysis compared the efficacy of IVIG and PE in treating GBS patients with severe symptoms.

Methodology

Six electronic databases, including PubMed, Embase, Scopus, ScienceDirect, Medline, and Google scholar, were scoured for articles related and relevant to our research. Additionally, more studies were obtained through the reference lists of the studies retrieved from these electronic databases. Quality assessment and statistical data analysis were conducted using Review Manager software (RevMan 5.4.1).

Results

The search for relevant articles resulted in 3253 articles, of which only 20 were included for review in the current study. A sub-group analysis indicated no significant difference in the curative effect (Hughes score reduces by at least one score 4 weeks after GBS treatment; OR: 1.00; 95% CI: 0.66-1.52; p = 1.00 and Achieving grade 0 or 1 on Hughes scale; OR: 1.03; 95% CI: 0.27-3.94; p = 0.97). Similarly, the statistical showed that the difference in length of hospitalization and duration of mechanical ventilation was insignificant between the IVIG and PE group (Standard Mean Difference (SMD): -0.45; 95% CI: -0.92, 0.02; I2 = 91%; p = 0.06 and SMD: -0.54; 95% CI: -1.67, 0.59; I2 = 93%; p = 0.35, respectively). Moreover, the meta-analysis did not find any significant difference in the risk of GBS relapse (RR: 0.47; 95% CI: 0.20-1.14; p = 0.10) and risk of complications related to the treatment regimens (RR: 1.03; 95% CI: 0.71-1.48; p = 0.89). However, the statistical analysis of outcomes from 3 studies showed that the risk of discontinuation was significantly lower in the IVIG group than in the PE group (RR: 0.22; 95% CI: 0.06-0.88; p = 0.03).

Conclusion

Our study suggests that IVIG and PE have similar curative effects. Similarly, IVIG seems easier to use and thus can be preferred for treating GBS.

The potential for treg-enhancing therapies in nervous system pathologies

While inflammation may not be the cause of disease, it is well known that it contributes to disease pathogenesis across a multitude of peripheral and central nervous system disorders. Chronic and overactive inflammation due to an effector T-cell-mediated aberrant immune response ultimately leads to tissue damage and neuronal cell death. To counteract peripheral and neuroinflammatory responses, research is being focused on regulatory T cell enhancement as a therapeutic target. Regulatory T cells are an immunosuppressive subpopulation of CD4+ T helper cells essential for maintaining immune homeostasis. The cells play pivotal roles in suppressing immune responses to maintain immune tolerance. In so doing, they control T cell proliferation and pro-inflammatory cytokine production curtailing autoimmunity and inflammation. For nervous system pathologies, Treg are known to affect the onset and tempo of neural injuries. To this end, we review recent findings supporting Treg's role in disease, as well as serving as a therapeutic agent in multiple sclerosis, myasthenia gravis, Guillain-Barre syndrome, Parkinson's and Alzheimer's diseases, and amyotrophic lateral sclerosis. An ever-broader role for Treg in the control of neurologic disease has been shown for traumatic brain injury, stroke, neurotrophic pain, epilepsy, and psychiatric disorders. To such ends, this review serves to examine the role played by Tregs in nervous system diseases with a focus on harnessing their functional therapeutic role(s).

B.infantis enhances immunotherapy for Guillain-Barre syndrome through regulating PD-1

BACKGROUND

Guillain-Barré syndrome (GBS) is a rare, autoimmune disease. B.infantis is reported to be effective in alleviating GBS by regulating abnormal function of T helper (Th) cells.

OBJECTIVES

In this study, T cells were isolated from healthy and GBS patients. The therapeutic effect of Bifidobacterium infantis (B.infantis) and whether it is achieved by PD-1 was examined at cellular and animal models.

METHODS

We used CCK-8, flow cytometry and real-time PCR to determine the differentiation of T cell subsets at cellular level. Then, an experimental autoimmune neuritis (EAN) animal model using six-week SD rats (n = 30, male) weighing 180-200 g was established to support the role of B. infantis in GBS through PD-1.

RESULTS

B. infantis inhibited the proliferation and promoted apoptosis of T cells from GBS. At the same time, the expression levels of PD-1 increased, which was correlated with decreased T-bet (Th1) and ROR-γt (Th17) and increased Foxp3 (Treg) expression. Moreover, B. infantis alleviated the symptoms of GBS. Th1 and Th17 cells decreased while Treg cells increased after B. infantis treatment, which could be partly abrogated by PD-1 inhibitor.

CONCLUSIONS

We concluded from this study that B.infantis alleviated GBS partly through PD-1.

Intravenous Immunoglobulins Promote an Expansion of Monocytic Myeloid-Derived Suppressor Cells (MDSC) in CVID Patients

Common variable immunodeficiency disorders (CVID), the most common primary immune deficiency, includes heterogeneous syndromes characterized by hypogammaglobulinemia and impaired antibody responses. CVID patients frequently suffer from recurrent infections and inflammatory conditions. Currently, immunoglobulin replacement therapy (IgRT) is the first-line treatment to prevent infections and aminorate immune alterations in CVID patients. Intravenous Immunoglobulin (IVIg), a preparation of highly purified poly-specific IgG, is used for treatment of immunodeficiencies as well as for autoimmune and inflammatory disorders, as IVIg exerts immunoregulatory and anti-inflammatory actions on innate and adaptive immune cells. To determine the mechanism of action of IVIg in CVID in vivo, we determined the effect of IVIg infusion on the transcriptome of peripheral blood mononuclear cells from CVID patients, and found that peripheral blood monocytes are primary targets of IVIg in vivo, and that IVIg triggers the acquisition of an anti-inflammatory gene profile in human monocytes. Moreover, IVIg altered the relative proportions of peripheral blood monocyte subsets and enhanced the proportion of CD14⁺ cells with a transcriptional, phenotypic, and functional profile that resembles that of monocytic myeloid-derived suppressor cells (MDSC). Therefore, our results indicate that CD14 + MDSC-like cells might contribute to the immunoregulatory effects of IVIg in CVID and other inflammatory disorders.

Proportion of peripheral regulatory T cells in patients with autoimmune encephalitis

PURPOSE

Regulatory T cells (Tregs) play a crucial role in maintaining immune tolerance. Any deficiency or dysfunction of the Tregs can influence the pathogenesis of autoimmune disease. This study aimed to assess the role of Tregs among patients with autoimmune encephalitis (AE) with different autoantibody types and to evaluate their association with clinical features.

METHODS

This was a cross-sectional observational study involving 29 patients with AE. Peripheral blood was sampled from each patient for flow cytometric analysis. Proportions of CD4⁺CD25⁺ and CD4⁺CD25⁺Foxp3⁺ Tregs were calculated and compared between the antibody types (synaptic, paraneoplastic, and undetermined). Associations between the proportion of Tregs and clinical features were also evaluated.

RESULTS

Five patients had synaptic autoantibodies, five had paraneoplastic autoantibodies, and the others were of an undetermined type. The proportion of CD4⁺CD25⁺ Tregs tended to be higher in those with paraneoplastic antibodies than in those with synaptic antibodies (post-hoc p = 0.028) and undetermined antibody status (post-hoc p = 0.043). A significant negative correlation was found between the proportion of Tregs and the initial modified Rankin score (r = -0.391, p = 0.036). Those who received intravenous immunoglobulin had lower proportions of Tregs than those who did not.

CONCLUSION

The results of the present study suggest that Tregs may play different roles according to the type of AE and may be linked to disease severity.

New insights into IVIg mechanisms and alternatives in autoimmune and inflammatory diseases

PURPOSE OF REVIEW

Intravenous immunoglobulin (IVIg) is an effective treatment for an increasing number of autoimmune and inflammatory conditions. However, IVIg continues to be limited by problems of potential shortages and cost. A number of mechanisms have been described for IVIg, which have been captured in newly emergent IVIg mimetic and IVIg alternative therapies. This review discusses the recent developments in IVIg mimetics and alternatives.

RECENT FINDINGS

Newly emergent IVIg mimetics and alternatives capture major proposed mechanisms of IVIg, including FcγR blockade, FcRn inhibition, complement inhibition, immune complex mimetics and sialylated IgG. Many of these emergent therapies have promising preclinical and clinical trial results.

SUMMARY

Significant research has been undertaken into the mechanism of IVIg in the treatment of autoimmune and inflammatory disease. Understanding the major IVIg mechanisms has allowed for rational development of IVIg mimetics and alternatives for several IVIg-treatable diseases.

In-depth peripheral CD4+ T profile correlates with myasthenic crisis

Objective

Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies against neuromuscular junctions. Myasthenic crisis (MC) represents the most severe state of MG with high in‐hospital mortality. We aimed to identify immune signatures using in‐depth profiling in MC, and to assess the correlations between immune biomarkers with clinical severity longitudinally.

Methods

We studied 181 participants including 57 healthy controls, 96 patients with MG who never experienced crisis and 28 MC patients from December 2018 through June 2020. Follow‐up visits occurred prospectively from crisis to 6 months off‐mechanical ventilation. The frequencies of 20 CD4⁺ T subpopulations and 18 serum cytokines were associated with clinical scores using correlations and principal component analysis.

Results

Patients in crisis exhibited a proinflammatory CD4⁺T response with elevated Th1 (P = 0.026), and Th17 cells (P = 0.032); decreased T follicular helper 2 (Tfh2) cells (P < 0.001), Tnaive in Tfh cells (P < 0.001), ICOS⁻Tfh cells (P = 0.017), and T central memory in Tfh (P = 0.022) compared with controls, and increased frequencies of Tregs (P = 0.026) and Tfh17 (P = 0.045) compared with non‐crisis MG. Cytokine cascade was identified in crisis including the ones associated with Th1 (IL‐1β/2/12p70/18/27/IFN‐γ/TNF‐α), Th2 (IL‐4/5/13), Th17 (IL‐6/17A/21/22/23/GM‐CSF), Th9 (IL‐9), and Treg (IL‐10). Longitudinally, seven immune biomarkers including Tregs, IL‐2/4/17A/IFN‐γ/TNF‐α/GM‐CSF had significant correlations with MG‐activities of daily living score.

Interpretation

Vigorous inflammatory CD4⁺ T signatures were identified in MC and are associated with clinical severity. Future research is needed to explore its potential candidacy for therapeutic intervention and predicting impending crisis.

Role of Resolvins in the Inflammatory Resolution of Neurological Diseases

The occurrence of neurological diseases including neurodegenerative disorders, neuroimmune diseases, and cerebrovascular disorders is closely related to neuroinflammation. Inflammation is a response against infection or injury. Genetic abnormalities, the aging process, or environmental factors can lead to dysregulation of the inflammatory response. Our immune system can cause massive damage when the inflammatory response becomes dysregulated. Inflammatory resolution is an effective process that terminates the inflammatory response to maintain health. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are omega-three polyunsaturated fatty acids that play a crucial regulatory role in the development of inflammation. Resolvins (Rvs) derived from EPA and DHA constitute the Rvs E and Rvs D series, respectively. Numerous studies on the effect of Rvs over inflammation using animal models reveal that they have both anti-inflammatory and pro-resolving capabilities. Here, we review the current knowledge on the classification, biosynthesis, receptors, mechanisms of action, and role of Rvs in neurological diseases.

Therapeutic normal IgG intravenous immunoglobulin activates Wnt-β-catenin pathway in dendritic cells

Therapeutic normal IgG intravenous immunoglobulin (IVIG) is a well-established first-line immunotherapy for many autoimmune and inflammatory diseases. Though several mechanisms have been proposed for the anti-inflammatory actions of IVIG, associated signaling pathways are not well studied. As β-catenin, the central component of the canonical Wnt pathway, plays an important role in imparting tolerogenic properties to dendritic cells (DCs) and in reducing inflammation, we explored whether IVIG induces the β-catenin pathway to exert anti-inflammatory effects. We show that IVIG in an IgG-sialylation independent manner activates β-catenin in human DCs along with upregulation of Wnt5a secretion. Mechanistically, β-catenin activation by IVIG requires intact IgG and LRP5/6 co-receptors, but FcγRIIA and Syk are not implicated. Despite induction of β-catenin, this pathway is dispensable for anti-inflammatory actions of IVIG in vitro and for mediating the protection against experimental autoimmune encephalomyelitis in vivo in mice, and reciprocal regulation of effector Th17/Th1 and regulatory T cells.