The immunopathology of B lymphocytes during stroke-induced injury and repair

The effect of anti-CD20 on inflammation and histopathological alternations in rat photothrombotic ischemic stroke model

Ischemic stroke (IS) has remained the main cause of mortality and neurological disabilities worldwide. Anti-CD20 treatments have a potent anti-inflammatory effect. Here, we investigated the effect of anti-CD20 on IS-induced inflammation and histopathologic changes in the rat model. Male Sprague-Dawley rats were divided into three groups: control, sham, and stroke. Rats in the stroke groups underwent photothrombosis-induced IS in the sensorimotor cortex area. They were divided into the following subgroups: treated with anti-CD20 after ischemia and killed after 5 and/or 10 days of IS. Histological changes were assessed by hematoxylin and eosin staining. mRNA levels of inflammation markers (VIM, ANXA3, SLC22 A4, and ADM), and also levels of transcription factors for Th1, Th2, and Th17 subsets (Tbet, GATA3, and ROR-γ, respectively), and also Foxp3 were detected in the peripheral blood mononuclear cells by quantitative real-time PCR. The levels of ADM and SLC22 A4 increased following IS on the 5th and 10th days, while treatment with anti-CD20 reversed their levels. Anti-CD20 therapy attenuated inflammation through down-regulation of VIM and ANXA3 after 10 days. This therapeutic effect was mainly mediated by the downregulation of Th1-Th17-driven inflammatory responses (Tbet and RORγt) and the upregulation of Th2 activities (GATA- 3). In addition, anti-CD20 increased the expression of Foxp3. Anti-CD20 treatment can also reduce brain tissue damage after 10 days. Our data showed that inflammation and histopathological alterations are associated with the photothrombotic model of IS, while treatment with anti-CD20 could reduce inflammation and alleviate histopathological changes.

Circulating Neutrophil-to-Lymphocyte Ratio Predicts Stroke-Associated Infection and Poststroke Fatigue Affecting Long-Term Neurological Outcomes in Stroke Patients

Background: Since peripheral leukocytes may contribute to the pathophysiology of stroke, the aim of this study was to elucidate the relationship between leukocytes and stroke outcomes and identify which leukocyte subtypes most accurately predict functional outcomes and poststroke fatigue (PSF) in stroke patients. Methods: A total of 788 ischemic stroke patients within 72 h of onset of disease were admitted in our study. Stroke-associated infection (SAI) and PSF were evaluated according to diagnosis standards by a special neurologist. Analyses were performed using SPSS 23.0 and GraphPad Prism 10.0. Results: Neutrophil-to-lymphocyte ratio (NLR) has discriminative power in predicting stroke outcome, and the area under the curve (AUC) of NLR to distinguish stroke outcomes was 0.689 (95% confidence interval, 0.646-0.732). Positive correlation was found between NLR levels and NIHSS score on admission (r = 0.2786, p < 0.001). Risk model for predicting stroke outcome was constructed using age, NIHSS, previous stroke history, triglycerides, glucose and hemoglobin levels, thrombolysis treatment, and NLR, with an AUC of 0.865. Patients who developed SAI and PSF both had significantly higher NLR levels at admission than those patients not diagnosed with SAI and PSF (p < 0.0001). A risk model was constructed to predict PSF based on parameters including age, NIHSS score, lipoprotein(a) and NLR, and an AUC of 0.751. Conclusions: Higher NLR levels in the acute phase of stroke might indicate a higher incidence of SAI and PSF. Therefore, higher NLR is associated with a poor stroke prognosis.

CD19+ B cell depletion: a novel strategy to alleviate ischemic stroke damage

Background

Ischemic stroke, accounting for approximately 80% of all stroke cases, is a major public health challenge and a leading cause of death and disability worldwide. Current treatments primarily involve thrombolytic therapy, limited to a 4.5-hour window due to the risk of complications, underscoring the need for new therapeutic targets. Systemic inflammation plays a critical role in stroke progression, with immune cells infiltrating the brain and exacerbating damage. B cells, in particular, have been implicated in stroke pathogenesis, although their exact role remains contentious. This study examines anti-CD19 antibody (aCD19 Ab) treatment in a stroke model to determine if CD19+ B cell depletion can reduce infarct size and alleviate inflammation.

Results

This study investigated whether temporary inhibition of B-cell activity using an aCD19 Ab could alleviate ischemic brain injury in a stroke mouse model by regulating cerebral and systemic immune reactions. Mice subjected to middle cerebral artery occlusion (MCAO) exhibited significant reductions in infarct size and brain edema, prolonged post-MCAO survival, and improved behavioral outcomes following aCD19 Ab treatment. Transmission electron microscopy (TEM) and Computed Tomography Angiography (CTA) results revealed a reduction in microvascular endothelial edema, decreased mitochondrial damage in neurons, reduced neuronal apoptosis, and a favorable reconstruction of the cerebral vascular network. Additionally, B cell inhibition reduced pro-inflammatory cytokines and immune cells in the brain and peripheral circulation. The immune response alterations observed in the MCAO/R group were consistent with the trends indicated by stroke patient data.

Conclusions

Temporary inhibition of B-cell activity via aCD19 antibody injection alleviated ischemic brain injury in a mouse model of stroke by suppressing systemic immune reactions. Changes in immune cells within the meninges may play a role, and further investigation is needed to understand the mechanisms involved. These findings suggest that cerebral and systemic immune responses contribute to the pathogenesis of ischemic stroke, and temporary B cell depletion may represent a potential therapeutic target for stroke therapy.

Profiling X chromosome genes expression relevant to sex dimorphism in stroke: insights from transcriptomics landscape analysis

Introduction

Although age is the most important non-modifiable risk factor for cerebral stroke, it is also apparent that females commonly exhibit longer lifespan and better outcome after stroke compared to the age-matched males. A critical event after stroke is the peripheral infiltration of immune cells across damaged blood-brain barrier, which induces inflammatory and immune responses within the brain parenchyma and consequently worsen brain injury. These events are also dependent on age and display a sex different pattern. Theoretically, X chromosome-encoded differential expression genes (DEGs) may explain differences between the sexes. However, the expression and regulation of these DEGs after stroke have not been studied in detail.

Methods

We conducted three datasets of human blood cells, mice brain, mice microglia and T cells that were previously published, and analyzed the contribution of gender, age and stroke insult on the X chromosome-encoded DEGs.

Results

The main findings were (i) compared to age, the stroke/hypoxia was a more potent factor in eliciting the DEGs. Particularly, older stroke patients exhibited more changes compared to young stroke group. (ii) After a stroke, the DEGs was diversely influenced by sex, age and cell types being studied. Particularly, either aging or gender led to more striking changes in brain-infiltrating T cells than in the resident immune cells.

Discussion

These findings highlight the complex interplay between sex, age, and immune responses in mediating stroke incidence and outcome. Investigation of the identified X chromosome-encoded genes in brain-infiltrating T cells deserves high priority, as they may play more important roles in explaining gender-related differences in stroke and brain injury.

Gender and Age Differences in Seronegative Pediatric Acute Disseminated Encephalomyelitis Profiles: Results and Insights from a Tertiary Center

Objectives

Acute disseminated encephalomyelitis (ADEM) is a rapid-onset inflammatory central nervous system (CNS) disorder in children, causing demyelination, encephalopathy, and neurological deficits, often following infections.

Materials & Methods

This 10-year retrospective study evaluated pediatric patients with seronegative acute disseminated encephalomyelitis (ADEM), focusing on clinical, laboratory, and imaging profiles. The various profiles were assessed to determine age- and/or sex-based differences.

Results

The study reviewed 36 patients, with an average age of 6.08 years and predominantly male (61.1%). Clinical presentations included fever, nausea, vomiting, and seizures, with left facial hemiparesis being more common in girls (P-value = 0.023), while abnormal deep tendon reflexes (DTRs) and right-sided pathologies were more common in older patients (P-value < 0.05). Recent laboratory results have revealed differences between peripheral lymphocytes and polymorphonuclear (PMN) cells. Imaging revealed predominantly bilateral lesions, with older patients more likely to show lesions in the right parietal and occipital lobes (P-value = 0.01 and 0.04). Bilateral parietal lobe lesions were significantly correlated with several laboratory findings across the different subgroups. Multivariate logistic regression revealed that these findings were statistically significant in regards to peripheral PMN and lymphocytes in the age category and cerebrospinal fluid (CSF) protein in the gender category (P-value < 0.05). Additionally, girls, particularly those who were older, had significantly higher involvement of the cervical spine (P-value = 0.04 and 0.02).

Conclusion

This study reveals age and sex-related differences in the clinical presentation and imaging findings of seronegative pediatric ADEM, showcasing the various demographic factors in patient profiles.

Post-stroke depression: exploring gut microbiota-mediated barrier dysfunction through immune regulation

Post-stroke depression (PSD) is one of the most common and devastating neuropsychiatric complications in stroke patients, affecting more than one-third of survivors of ischemic stroke (IS). Despite its high incidence, PSD is often overlooked or undertreated in clinical practice, and effective preventive measures and therapeutic interventions remain limited. Although the exact mechanisms of PSD are not fully understood, emerging evidence suggests that the gut microbiota plays a key role in regulating gut-brain communication. This has sparked great interest in the relationship between the microbiota-gut-brain axis (MGBA) and PSD, especially in the context of cerebral ischemia. In addition to the gut microbiota, another important factor is the gut barrier, which acts as a frontline sensor distinguishing between beneficial and harmful microbes, regulating inflammatory responses and immunomodulation. Based on this, this paper proposes a new approach, the microbiota-immune-barrier axis, which is not only closely related to the pathophysiology of IS but may also play a critical role in the occurrence and progression of PSD. This review aims to systematically analyze how the gut microbiota affects the integrity and function of the barrier after IS through inflammatory responses and immunomodulation, leading to the production or exacerbation of depressive symptoms in the context of cerebral ischemia. In addition, we will explore existing technologies that can assess the MGBA and potential therapeutic strategies for PSD, with the hope of providing new insights for future research and clinical interventions.

Changes in Neuroimmunological Synapses During Cerebral Ischemia

The direct interplay between the immune and nervous systems is now well established. Within the brain, these interactions take place between neurons and resident glial cells, i.e., microglia and astrocytes, or infiltrating immune cells, influenced by systemic factors. A special form of physical cell-cell interactions is the so-called "neuroimmunological (NI) synapse." There is compelling evidence that the same signaling pathways that regulate inflammatory responses to injury or ischemia also play potent roles in brain development, plasticity, and function. Proper synaptic wiring is as important during development as it is during disease states, as it is necessary for activity-dependent refinement of neuronal circuits. Since the process of forming synaptic connections in the brain is highly dynamic, with constant changes in strength and connectivity, the immune component is perfectly suited for the regulatory task as it is in constant turnover. Many cellular and molecular players in this interaction remain to be uncovered, especially in pathological states. In this review, we discuss and propose possible communication hubs between components of the adaptive and innate immune systems and the synaptic element in ischemic stroke pathology.

Peripheral immunity is associated with cognitive impairment after acute minor ischemic stroke and transient ischemic attack

Immunoinflammation is associated with the development of post-stroke cognitive impairment (PSCI), however, peripheral immunity has not been fully explored. We aimed to investigate the association between PSCI and peripheral immune indicators, including neutrophil, lymphocyte, and mononuclear percentages and counts; the systemic immune inflammation index; platelet-to-lymphocyte ratio; neutrophil-to-lymphocyte ratio (NLR); and lymphocyte-to-monocyte ratio. A total of 224 patients with acute minor ischemic stroke or transient ischemic attack with 6-12 months of follow-up were included. PSCI was defined as a Montreal Cognitive Assessment score < 22 during the follow-up period. We performed logistic regression, subgroup analyses based on age and sex, and further established predictive models. We found that increased innate immunity indicators (neutrophils, neutrophil percentage) increased the risk of PSCI, whereas increased adaptive immunity indicator (lymphocytes) were protective against PSCI, especially in patients aged 50-65 years. Neutrophil percentage and NLR improved the predictive efficacy of the models that included demographic, clinical, and imaging information, with the area under the curve increased from 0.765 to 0.804 and 0.803 (P = 0.042 and 0.049, respectively). We conducted a comprehensive analysis of peripheral immunity in PSCI, providing a novel perspective on the early detection, etiology, and treatment of PSCI.

Comprehensive immune modulation mechanisms of Angong Niuhuang Wan in ischemic stroke: Insights from mass cytometry analysis

BACKGROUND

Angong Niuhuang Wan (AGNHW, ), is a classical medicinal formula in Traditional Chinese Medicine (TCM) that has been appreciated for its neuroprotective properties in ischemic cerebral injuries, yet its intricate mechanisms remain only partially elucidated.

AIMS

This study leverages advanced Mass cytometry (CyTOF) to analyze AGNHW's multifaceted immunomodulation effects in-depth, emphasizing previously underexplored areas.

RESULTS

AGNHW mitigated monocyte-derived macrophages (MoDM) infiltration in the brain, distinguishing its effects on those from microglia. While the vehicle group exhibited elevated inflammatory markers like CD4, CD8a, and CD44 in ischemic brains, the AGNHW-treated group attenuated their expressions, indicating AGNHW's potential to temper the post-ischemic inflammatory response. Systemically, AGNHW modulated fundamental immune cell dynamics, notably augmenting CD8+ T cells, B cells, monocytes, and neutrophil counts in the peripheral blood under post-stroke conditions. Intracellularly, AGNHW exhibited its targeted modulation of the signaling pathways, revealing a remarked inhibition of key markers like IκBα, indicating potential suppression of inflammatory responses in ischemic brain injuries.

CONCLUSION

This study offers a comprehensive portrait of AGNHW's immunomodulation effects on ischemic stroke, illuminating its dual sites of action-both cerebral and systemic-and its nuanced modulation of cellular and molecular dynamics.

Genetically supported causality between gut microbiota, immune cells, and ischemic stroke: a two-sample Mendelian randomization study

Background

Previous studies have highlighted a robust correlation between gut microbiota/immune cells and ischemic stroke (IS). However, the precise nature of their causal relationship remains uncertain. To address this gap, our study aims to meticulously investigate the causal association between gut microbiota/immune cells and the likelihood of developing IS, employing a two-sample Mendelian randomization (MR) analysis.

Methods

Our comprehensive analysis utilized summary statistics from genome-wide association studies (GWAS) on gut microbiota, immune cells, and IS. The primary MR method employed was the inverse variance-weighted (IVW) approach. To address potential pleiotropy and identify outlier genetic variants, we incorporated the Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) technique, along with MR-Egger regression. Heterogeneity was assessed using Cochran's Q-test. Additionally, leave-one-out analysis was conducted to pinpoint any individual genetic variant influencing the observed causal associations. Finally, a reverse MR analysis was performed to explore the potential of reverse causation.

Results

Our investigation revealed four gut microbial taxa and 16 immune cells with a significant causal relationship with IS (p < 0.05). Notably, two bacterial features and five immunophenotypes were strongly associated with a lower IS risk: genus.Barnesiella.id.944 (OR: 0.907, 95% CI: 0.836-0.983, p = 0.018), genus.LachnospiraceaeNK4A136group.id.11319 (OR: 0.918, 95% CI: 0.853-0.983, p = 0.988), Activated & resting Treg % CD4++ (OR: 0.977, 95% CI: 0.956-0.998, p = 0.028). Additionally, significant associations between IS risk and two bacterial features along with eleven immunophenotypes were observed: genus.Paraprevotella.id.962 (OR: 1.106, 95% CI: 1.043-1.172, p < 0.001), genus.Streptococcus.id.1853 (OR: 1.119, 95% CI: 1.034-1.210, p = 0.005), CD127 on granulocyte (OR: 1.039, 95% CI: 1.009-1.070, p = 0.011). Our analyses did not reveal heterogeneity based on the Cochrane's Q-test (p > 0.05) nor indicate instances of horizontal pleiotropy according to MR-Egger and MR-PRESSO analyses (p > 0.05). Furthermore, the robustness of our MR results was confirmed through leave-one-out analysis.

Conclusion

Our study provides further evidence supporting the potential association between gut microbiota and immune cells in relation to IS, shedding light on the underlying mechanisms that may contribute to this condition. These findings lay a solid foundation for future investigations into targeted prevention strategies.

Effects of immune cells on ischemic stroke and the mediating roles of metabolites

Objective

Previous studies have not shown an association between IgD-CD24-B-cell absolute count (IgD-CD24-AC) and ischemic stroke (IS). Our study aimed to assess the causal effect of IgD-CD24-AC on IS and to explore the role of ascorbic acid 2-sulfate (AA2S) as a potential mediator.

Methods

Our study was based on the largest available genome-wide association study (GWAS). Inverse variance weighting (IVW), MR-Egger, weighted median (WMN), simple mode, and weighted mode methods were used to assess causal effects, with IVW as the primary outcome. Subsequently, we further performed a two-step MR analysis to evaluate whether AA2S mediated this causal effect. In addition, several sensitivity analyses were conducted to evaluate heterogeneity, including Cochran's Q test, the MR-Egger intercept test, the MR-PRESSO global test, and the leave-one-out analysis.

Results

Using the IVW approach, the risk ratio of IgD-CD24-AC to IS was estimated to be 1.216 (95% CI = 1.079-1.371, p = 0.001). This result was supported by the WMN method (OR = 1.204, 95% CI = 1.020-1.421, p = 0.028) and the MR-Egger method (OR = 1.177, 95% CI = 0.962-1.442, p = 0.133). We also observed the same trend with the simple model and weighted model. Furthermore, the proportion of genetically predicted IgD-CD24-AC mediated through AA2S levels was 3.73%.

Conclusion

Our study revealed a causal relationship between IgD-CD24-AC and IS, a small part of which was mediated by AA2S. These findings offer critical insights for developing immune-targeted therapies in the future and lay a strong foundation for advancements in precision medicine.

Genetic insights into the relationship between immune cell characteristics and ischemic stroke: A bidirectional Mendelian randomization study

BACKGROUND AND PURPOSE

Ischemic stroke, a major contributor to global disability and mortality, is underpinned by intricate pathophysiological mechanisms, notably neuroinflammation and immune cell dynamics. Prior research has identified a nuanced and often paradoxical link between immune cell phenotypes and ischemic stroke susceptibility. The aim of this study was to elucidate the potential causal links between the median fluorescence intensity (MFI) and morphological parameters (MP) of 731 immune cell types and ischemic stroke risk.

METHODS

By analyzing extensive genetic datasets, we conducted comprehensive Mendelian randomization (MR) analyses to discern the genetic correlations between diverse immune cell attributes (MFI and MP) and ischemic stroke risk.

RESULTS

Our study identified key immune cell signatures linked to ischemic stroke risk. Both B cells and T cells, among other immune cell types, have a bidirectional influence on stroke risk. Notably, the regulatory T-cell phenotype demonstrates significant neuroprotective properties, with all odds ratio (OR) values and confidence intervals (CIs) being less than 1. Furthermore, CD39 phenotype immune cells, particularly CD39+ CD8+ T cells (inverse variance weighting [IVW] OR 0.92, 95% CI 0.87-0.97; p = 0.002) and CD39+ activated CD4 regulatory T cells (IVW OR 0.93, 95% CI 0.90-0.97; p < 0.001), show notable neuroprotection against ischemic stroke.

CONCLUSION

This investigation provides new genetic insights into the interplay between various immune cells and ischemic stroke, underscoring the complex role of immune processes in stroke pathogenesis. These findings lay a foundation for future research, which may confirm and expand upon these links, potentially leading to innovative immune-targeted therapies for stroke prevention and management.

B cells and the stressed brain: emerging evidence of neuroimmune interactions in the context of psychosocial stress and major depression

The immune system has emerged as a key regulator of central nervous system (CNS) function in health and in disease. Importantly, improved understanding of immune contributions to mood disorders has provided novel opportunities for the treatment of debilitating stress-related mental health conditions such as major depressive disorder (MDD). Yet, the impact to, and involvement of, B lymphocytes in the response to stress is not well-understood, leaving a fundamental gap in our knowledge underlying the immune theory of depression. Several emerging clinical and preclinical findings highlight pronounced consequences for B cells in stress and MDD and may indicate key roles for B cells in modulating mood. This review will describe the clinical and foundational observations implicating B cell-psychological stress interactions, discuss potential mechanisms by which B cells may impact brain function in the context of stress and mood disorders, describe research tools that support the investigation of their neurobiological impacts, and highlight remaining research questions. The goal here is for this discussion to illuminate both the scope and limitations of our current understanding regarding the role of B cells, stress, mood, and depression.

Circulating immune cell landscape and T-cell abnormalities in patients with moyamoya disease

BACKGROUND

Moyamoya disease (MMD) stands as a prominent cause of stroke among children and adolescents in East Asian populations. Although a growing body of evidence suggests that dysregulated inflammation and autoimmune responses might contribute to the development of MMD, a comprehensive and detailed understanding of the alterations in circulating immune cells associated with MMD remains elusive.

METHODS

In this study, we employed a combination of single-cell RNA sequencing (scRNA-seq), mass cytometry and RNA-sequencing techniques to compare immune cell profiles in peripheral blood samples obtained from patients with MMD and age-matched healthy controls.

RESULTS

Our investigation unveiled immune dysfunction in MMD patients, primarily characterized by perturbations in T-cell (TC) subpopulations, including a reduction in effector TCs and an increase in regulatory TCs (Tregs). Additionally, we observed diminished natural killer cells and dendritic cells alongside heightened B cells and monocytes in MMD patients. Notably, within the MMD group, there was an augmented proportion of fragile Tregs, whereas the stable Treg fraction decreased. MMD was also linked to heightened immune activation, as evidenced by elevated expression levels of HLA-DR and p-STAT3.

CONCLUSIONS

Our findings offer a comprehensive view of the circulating immune cell landscape in MMD patients. Immune dysregulation in patients with MMD was characterized by alterations in T-cell populations, including a decrease in effector T-cells and an increase in regulatory T-cells (Tregs), suggest a potential role for disrupted circulating immunity in the aetiology of MMD.

Updates of the role of B-cells in ischemic stroke

Ischemic stroke is a major disease causing death and disability in the elderly and is one of the major diseases that seriously threaten human health and cause a great economic burden. In the early stage of ischemic stroke, neuronal structure is destroyed, resulting in death or damage, and the release of a variety of damage-associated pattern molecules induces an increase in neuroglial activation, peripheral immune response, and secretion of inflammatory mediators, which further exacerbates the damage to the blood-brain barrier, exacerbates cerebral edema, and microcirculatory impairment, triggering secondary brain injuries. After the acute phase of stroke, various immune cells initiate a protective effect, which is released step by step and contributes to the repair of neuronal cells through phenotypic changes. In addition, ischemic stroke induces Central Nervous System (CNS) immunosuppression, and the interaction between the two influences the outcome of stroke. Therefore, modulating the immune response of the CNS to reduce the inflammatory response and immune damage during stroke is important for the protection of brain function and long-term recovery after stroke, and modulating the immune function of the CNS is expected to be a novel therapeutic strategy. However, there are fewer studies on B-cells in brain function protection, which may play a dual role in the stroke process, and the understanding of this cell is still incomplete. We review the existing studies on the mechanisms of the role of B-cells, inflammatory response, and immune response in the development of ischemic stroke and provide a reference for the development of adjuvant therapeutic drugs for ischemic stroke targeting inflammatory injury.

Peripheral blood CD19 positive B lymphocytes increase after ischemic stroke and correlate with carotid atherosclerosis

Introduction

Atherosclerosis is the primary pathological basis of ischemic stroke, and dyslipidemia is one of its major etiological factors. Acute ischemic stroke patients exhibit imbalances in lymphocyte subpopulations, yet the correlation between these dynamic changes in lymphocyte subpopulations and lipid metabolism disorders, as well as carotid atherosclerosis in stroke patients remains poorly understood.

Methods

We retrospectively analyzed the demographic data, risk factors of cerebrovascular disease, laboratory examination (lymphocyte subsets, lipid indexes, etc.), clinical features and c;/]-sity from December 2017 to September 2019 and non-stroke patients with dizziness/vertigo during the same period.

Results

The results showed that peripheral B lymphocyte proportions are elevated in acute ischemic stroke patients compared with those of the control group (13.6 ± 5.3 vs. 11.7 ± 4.4%, p = 0.006). Higher B lymphocyte proportions are associated with concurrent dyslipidemia, increased levels of vascular risk factors including triglycerides (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and very-low-density lipoprotein cholesterol (VLDL-C), as well as decreased levels of the protective factor high-density lipoprotein cholesterol (HDL-C). Elevated B lymphocyte proportions are independently correlated with carotid atherosclerosis in stroke patients.

Discussion

We found CD19 positive B Lymphocytes increase after ischemic stroke and correlate with Carotid Atherosclerosis. Lymphocyte subpopulations should be highlighted in stroke patients.

Elucidating the neuroimmunology of traumatic brain injury: methodological approaches to unravel intercellular communication and function

The neuroimmunology of traumatic brain injury (TBI) has recently gained recognition as a crucial element in the secondary pathophysiological consequences that occur following neurotrauma. Both immune cells residing within the central nervous system (CNS) and those migrating from the periphery play significant roles in the development of secondary brain injury. However, the precise mechanisms governing communication between innate and adaptive immune cells remain incompletely understood, partly due to a limited utilization of relevant experimental models and techniques. Therefore, in this discussion, we outline current methodologies that can aid in the exploration of TBI neuroimmunology, with a particular emphasis on the interactions between resident neuroglial cells and recruited lymphocytes. These techniques encompass adoptive cell transfer, intra-CNS injection(s), selective cellular depletion, genetic manipulation, molecular neuroimaging, as well as in vitro co-culture systems and the utilization of organoid models. By incorporating key elements of both innate and adaptive immunity, these methods facilitate the examination of clinically relevant interactions. In addition to these preclinical approaches, we also detail an emerging avenue of research that seeks to leverage human biofluids. This approach enables the investigation of how resident and infiltrating immune cells modulate neuroglial responses after TBI. Considering the growing significance of neuroinflammation in TBI, the introduction and application of advanced methodologies will be pivotal in advancing translational research in this field.