Association of B cell profile and receptor repertoire with the progression of Alzheimer's disease

Peripheral blood immune cell phenotypes and Alzheimer's disease: A mediation Mendelian randomization study

BackgroundAlzheimer's disease (AD) is a debilitating neurodegenerative disorder. Although peripheral immune cells have been implicated in the pathology of AD, the causal relationship between peripheral blood immune cells and AD remains to be fully elucidated.ObjectiveTo examine the association between peripheral blood immune cell phenotypes and AD, mediated by peripheral blood metabolite, a two-step Mendelian randomization (MR) analysis was performed.MethodsSummary statistics were obtained from the two largest independent cohorts. We explored bidirectional univariable MR analysis to explore causal associations and assessed the mediated proportion of peripheral blood metabolite phenotypes.ResultsThe proportion of IgD + CD38- B cells (Bm1) were found to increase the risk of AD in both the FinnGen database (p = 0.033) and the UK Biobank (p = 0.034). Conversely, hematopoietic stem cells were associated with a decreased risk of AD in the FinnGen database (p = 0.045) and the UK Biobank (p = 0.017). Mediation analysis revealed indirect effects of the proportion of Bm1 on AD through cysteine levels (β = 5 × 10-3), Acetylcarnitine (C2) to propionylcarnitine (C3) ratio (β = 4.5 × 10-3), and Gamma-glutamyl-alpha-lysine levels (β = 2.6 × 10-3), with mediated proportion of 19.4%, 16.9% and 9.6% of the total effect, respectively. Additionally, hematopoietic stem cells influenced AD through Glycolithocholate sulfate levels (β = 1.5 × 10-3), with a mediated proportion of 3.5%.ConclusionsOur findings demonstrate that two peripheral blood immune cell phenotypes impact the risk of AD. These immune cells may influence AD through various peripheral blood metabolite, identifying potential intervention targets for individuals at risk.

Fingolimod ameliorates amyloid deposition and neurodegeneration in APP/PS1 mouse model of Alzheimer's disease

INTRODUCTION

The immune system plays a critical role in regulating amyloid-beta (Aβ) metabolism in Alzheimer's Disease (AD). Both T and B lymphocytes are involved in the pathogenesis of AD. The sphingosine-1-phosphate (S1P) receptor modulator fingolimod used in the treatment of multiple sclerosis, can promote lymphocyte homing, potentially reducing the infiltration of peripheral lymphocytes into the brain.

METHODS

In this study, 8-month-old APP/PS1 mice were orally administered fingolimod at a dose of 1 mg/kg/day or saline as a control for 2 months. After treatment, the mice were subjected to behavioral tests, pathological examinations, and biochemical analyses to evaluate behavioral deficits and AD-type pathologies.

RESULTS

Fingolimod inhibits the infiltration of peripheral lymphocytes into the brain and reduces neuroinflammation. Fingolimod enhances cognitive function and alleviates brain Aβ deposition. Additionally, fingolimod treatment mitigates other AD-related pathologies, including Tau hyperphosphorylation, neuroinflammation, and neurodegeneration. Proteomic analysis further confirms the therapeutic effects of fingolimod in AD, reflected by the downregulation of proteins involved in multiple AD-associated pathways.

DISCUSSION

This study illustrates that fingolimod effectively ameliorates multiple pathological features of AD, highlighting its potential as a promising therapeutic candidate for the disease.

Phenotypic alterations in peripheral blood B Lymphocytes of patients with Alzheimer's Disease

INTRODUCTION

Dysfunction of humoral immunity has been implicated in the pathogenesis of Alzheimer's disease (AD). The distribution of B lymphocyte subsets and their clinical relevance in AD remain unclear.

OBJECTIVE

In this study, we aimed to investigate the distribution of peripheral blood B lymphocyte subsets and their relevance with cognition and biomarkers in AD.

DESIGN, SETTING, AND PARTICIPANTS

We evaluated the immunophenotype of peripheral B lymphocytes in 27 AD patients confirmed by PET-Amyloid scan and 32 cognitively normal controls.

RESULTS

The phenotype of B lymphocytes is altered in AD patients. AD patients exhibit a decrease in both the numbers and proportions of switched memory (SwM) B cells and double-negative (DN) B cells. The proportion of unswitched memory (USwM) B cells was increased after in vitro stimulation. Additionally, B cells that produce proinflammatory cytokines including GM-CSF, IFN-γ, and TNF-α are increased, while those that produce the anti-inflammatory cytokine IL-10 are decreased in AD patients after in vitro stimulation. These alterations in B cell populations were linked to cognitive functions and biomarkers, including Aβ42/40 and pTau181, in AD patients.

DISCUSSION

This study reveals an altered B-lymphocyte phenotype in AD patients, marked by functional and compositional dysregulation. Further research incorporating mechanistic, longitudinal, and functional studies is needed to determine whether these immune perturbations directly contribute to AD pathogenesis or arise as secondary effects of neurodegeneration.

Peripheral and central neuroimmune mechanisms in Alzheimer's disease pathogenesis

Alzheimer's disease (AD) poses a growing global health challenge as populations age. Recent research highlights the crucial role of peripheral immunity in AD pathogenesis. This review explores how blood-brain barrier disruption allows peripheral immune cells to infiltrate the central nervous system (CNS), worsening neuroinflammation and disease progression. We examine recent findings on interactions between peripheral immune cells and CNS-resident microglia, forming a self-perpetuating inflammatory cycle leading to neuronal dysfunction. Moreover, this review emphasizes recent developments in the dysregulation of immune factors from both the periphery and CNS, and their impact on AD progression. With ongoing research and development of new therapeutic strategies, this review underscores the importance of modulating interactions between the peripheral immune system and CNS in AD therapy.

Transcriptome analysis of early- and late-onset Alzheimer's disease in Korean cohorts

INTRODUCTION

The molecular mechanisms underlying early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD) remain incompletely understood, particularly in Asian populations.

METHODS

RNA-sequencing was carried out on blood samples from 248 participants in the Seoul National University Bundang Hospital cohort to perform differential gene expression (DGE) and weighted gene co-expression network analysis. Findings were replicated in an independent Korean cohort (N = 275).

RESULTS

DGE analysis identified 18 and 88 dysregulated genes in EOAD and LOAD, respectively. Network analysis identified a LOAD-associated module showing a significant enrichment in pathways related to mitophagy, 5' adenosine monophosphate-activated protein kinase signaling, and ubiquitin-mediated proteolysis. In the replication cohort, downregulation of SMOX and PLVAP in LOAD was replicated, and the LOAD-associated module was highly preserved. In addition, SMOX and PLVAP were associated with brain amyloid beta deposition.

DISCUSSION

Our findings suggest distinct molecular signatures for EOAD and LOAD in a Korean population, providing deeper understanding of their diagnostic potential and molecular mechanisms.

HIGHLIGHTS

Analysis identified 18 and 88 dysregulated genes in early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD), respectively. Expression levels of SMOX and PLVAP were downregulated in LOAD. Expression levels of SMOX and PLVAP were associated with brain amyloid beta deposition. Pathways including mitophagy and 5' adenosine monophosphate-activated protein kinase signaling were enriched in a LOAD module. A LOAD module was highly preserved across two independent cohorts.

Novel method for detection of Aβ and Iso-D7-Aβ N-terminus-specific B cells and Iso-D7-Aβ-specific antibodies

Alzheimer's disease (AD) is a multifactorial systemic disease that is triggered, at least in part, by the accumulation of β-amyloid (Aβ) peptides in the brain, but it also depends on immune system-mediated regulation. Recent studies suggest that B cells may play a role in AD development and point to the accumulation of clonally expanded B cells in AD patients. However, the specificity of the clonally expanded B cells is unknown, and the contribution of Aβ-specific B cells to AD pathology development is unclear. In this study, we have developed a novel method to identify Aβ-specific B cells by flow cytometry using fluorescent tetramers. The suggested method also enables the identification of B-cell clones specific to a more pathology-provoking form of Aβ with an isomerized Asp7 residue (Iso-D7-Aβ) that accumulates in elderly people and in AD patients. The method has been verified using mice immunized with antigens containing the isomerized or non-isomerized Aβ N-terminus peptides. In addition, we describe a new method for the detection of Iso-D7-Aβ-specific antibodies, which was tested on mouse serum. These methods are of potential importance in research aimed at studying AD and may be also utilized for diagnostic and therapeutic purposes.

Smoking Impacts Alzheimer's Disease Progression Through Oral Microbiota Modulation

Alzheimer's disease (AD) is an important public health challenge with a limited understanding of its pathogenesis. Smoking is a significant modifiable risk factor for AD progression, and its specific mechanism is often interpreted from a toxicological perspective. However, microbial infections also contribute to AD, with oral microbiota playing a crucial role in its progression. Notably, smoking alters the ecological structure and pathogenicity of the oral microbiota. Currently, there is no systematic review or summary of the relationship between these three factors; thus, understanding this association can help in the development of new treatments. This review summarizes the connections between smoking, AD, and oral microbiota from existing research. It also explores how smoking affects the occurrence and development of AD through oral microbiota, and examines treatments for oral microbiota that delay the progression of AD. Furthermore, this review emphasizes the potential of the oral microbiota to act as a biomarker for AD. Finally, it considers the feasibility of probiotics and oral antibacterial therapy to expand treatment methods for AD.

Alzheimer's disease and the immune system: A comprehensive overview with a focus on B cells, humoral immunity, and immunotherapy

Alzheimer's disease (AD) is a complex neurodegenerative disorder and the major cause of dementia. Amyloid-β (Aβ) and tau aggregation, mitochondrial dysfunction, and microglial dysregulation are key contributors to AD pathogenesis. Impairments in the blood-brain barrier have unveiled the contribution of the immune system, particularly B cells, in AD pathology. B cells, a crucial component of adaptive immunity, exhibit diverse functions, including antigen presentation and antibody production. While their role in neuroinflammatory disorders has been well-documented, their specific function in AD lacks adequate data. This review examines the dual role of the B cells and humoral immunity in modulating brain inflammation in AD and explores recent advancements in passive and active immunotherapeutic strategies targeting AD pathobiology. We summarize preclinical and clinical studies investigating B cell frequency, altered antibody levels, and their implications in neuroinflammation and immunotherapy. Notably, B cells demonstrate protective and pathological roles in AD, influencing neurodegeneration through antibody-mediated clearance of toxic aggregates and inflammatory activation inflammation. Passive immunotherapies targeting Aβ have shown potential in reducing amyloid plaques, while active immunotherapies are emerging as promising strategies, requiring further validation. Understanding the interplay between B cells, humoral immunity, microglia, and mitochondrial dysfunction is critical to unraveling AD pathogenesis. Their dual nature in disease progression underscores the need for precise therapeutic interventions to optimize immunotherapy outcomes and mitigate neuroinflammation effectively.

Effects of Intestinal M Cells on Intestinal Barrier and Neuropathological Properties in an AD Mouse Model

Intestinal microfold cells (M cells) play a critical role in the immune response of the intestinal mucosa by actively taking up antigens, facilitating antigen presentation to immune cells, and promoting the production of secretory immunoglobulin A by B cells. Despite their known important functions in the gut, the effect of M cells on the central nervous system remains unclear. We investigated the expression of M cell-related factor genes and protein levels in Peyer's patches (PPs) of 3-month-old and 9-month-old APP/PS1 mice, as well as the expression of intestinal barrier proteins in the ileum and colon of these mice. Furthermore, we employed intestinal M cell conditional ablation mice (i.e., RankΔIEC mice) to assess the influence of M cells on the intestinal barrier and Alzheimer's disease (AD)-like behavioral and pathological features. Our findings revealed that compared to wild-type mice, APP/PS1 mice showed altered M cell-related genes and disrupted intestinal barriers. In addition, there is a significant decrease in glycoprotein 2 (GP2) mRNA levels in the PPs of 3-month-old APP/PS1 mice, with the relative expression of GP2 mRNA tending to zero. Parameters related to the intestinal barrier (IgA, MUC2, Claudin-5, ZO-1) were significantly downregulated in both 3-month-old and 9-month-old APP/PS1 mice compared to wild-type controls, and the differences were more pronounced in the 9-month-old mice. Moreover, M cell ablation in APP/PS1 mice (i.e., APP/PS1ΔMC mice) resulted in more severe intestinal barrier destruction. Notably, we observed through water maze experiments that APP/PS1ΔMC mice at 6 months of age exhibited significantly poorer spatial learning memory compared to APP/PS1 mice. And the neuropathological alterations were also observed in APP/PS1ΔMC mice at 6 months of age that when intestinal M cells are damaged in APP/PS1 mice, brain microglia are activated, Tau phosphorylation is exacerbated, and the number of neurons is reduced. Our results suggest for the first time that the absence of intestinal M cells might further aggravate intestinal leakage, lead to neuropathological damage, and subsequently cause the impairment of learning memory ability in AD mice. Our research highlights the impact of intestinal M cells on the intestinal barrier and AD neuropathogenesis in AD mouse model.

GREMI: An Explainable Multi-Omics Integration Framework for Enhanced Disease Prediction and Module Identification

Multi-omics integration has demonstrated promising performance in complex disease prediction. However, existing research typically focuses on maximizing prediction accuracy, while often neglecting the essential task of discovering meaningful biomarkers. This issue is particularly important in biomedicine, as molecules often interact rather than function individually to influence disease outcomes. To this end, we propose a two-phase framework named GREMI to assist multi-omics classification and explanation. In the prediction phase, we propose to improve prediction performance by employing a graph attention architecture on sample-wise co-functional networks to incorporate biomolecular interaction information for enhanced feature representation, followed by the integration of a joint-late mixed strategy and the true-class-probability block to adaptively evaluate classification confidence at both feature and omics levels. In the interpretation phase, we propose a multi-view approach to explain disease outcomes from the interaction module perspective, providing a more intuitive understanding and biomedical rationale. We incorporate Monte Carlo tree search (MCTS) to explore local-view subgraphs and pinpoint modules that highly contribute to disease characterization from the global-view. Extensive experiments demonstrate that the proposed framework outperforms state-of-the-art methods in seven different classification tasks, and our model effectively addresses data mutual interference when the number of omics types increases. We further illustrate the functional- and disease-relevance of the identified modules, as well as validate the classification performance of discovered modules using an independent cohort.

Exploring resveratrol against Alzheimer's disease and Parkinson's disease through integrating network pharmacology, bioinformatics, and experimental validation strategy in vitro

Background

The study aims to investigate the pharmacological basis and molecular mechanisms of resveratrol in the treatment of Alzheimer's disease (AD) and Parkinson's disease (PD) through the approach of treating different diseases with the same method, guided by traditional Chinese medicine theory. Utilizing network pharmacology and bioinformatics methods, this research aims to provide modern medical evidence for the theory of treating different diseases with the same method in traditional Chinese medicine.

Methods

Omnibus from Swiss Target Prediction, TCMSP, SuperPred, SEA, HIT, CTD, TCMIP and Gene Expression Disease datasets for resveratrol related genes, Alzheimer's disease, and Parkinson's disease were obtained from the GEO database. Core targets were identified by weighted gene coexpression network analysis (WGCNA) and minimum absolute contraction and selection operator (LASSO). The expression of core targets was verified in AD and PD cell models. The immune characteristics of AD and PD were analyzed by CIBERSORT algorithm. Finally, the potential mechanism of resveratrol intervention on the core target was studied by molecular docking technique.

Results

The results of network pharmacological analysis showed that resveratrol acted on 85 common targets such as STAT3 and CASP3, affected AGE-RAGE signaling pathway and PI3K-Akt signaling pathway, and showed the effect of "same disease and different treatment" for AD and PD. Three core targets associated with AD and PD (PLK4, FCGRT, and PRKAR2A) were finally identified through comprehensive transcriptome analysis, and experimentally verified in cell models of AD and PD. At the same time, the analysis of immune cell infiltration suggested that AD and PD had dysregulation of inflammation, and the core target was significantly related to M2 macrophages.

Conclusion

Resveratrol may play a potential mechanism of "treating the same disease with different diseases" and target three core targets (PLK4, FCGRT and PRKAR2A) to improve the disease process of AD and PD by participating in the regulation of immune and inflammatory pathways. These findings have potential implications for clinical practice and future research.

β-Amyloids and Immune Responses Associated with Alzheimer's Disease

Alzheimer's disease (AD) is associated with the accumulation of β-amyloids (Aβs) and the formation of Aβ plaques in the brain. Various structural forms and isoforms of Aβs that have variable propensities for oligomerization and toxicity and may differentially affect the development of AD have been identified. In addition, there is evidence that β-amyloids are engaged in complex interactions with the innate and adaptive immune systems, both of which may also play a role in the regulation of AD onset and progression. In this review, we discuss what is currently known about the intricate interplay between β-amyloids and the immune response to Aβs with a more in-depth focus on the possible roles of B cells in the pathogenesis of AD.

Microglia Gravitate toward Amyloid Plaques Surrounded by Externalized Phosphatidylserine via TREM2

Microglia play a crucial role in synaptic elimination by engulfing dystrophic neurons via triggering receptors expressed on myeloid cells 2 (TREM2). They are also involved in the clearance of beta-amyloid (Aβ) plaques in Alzheimer's disease (AD); nonetheless, the driving force behind TREM2-mediated phagocytosis of beta-amyloid (Aβ) plaques remains unknown. Here, using advanced 2D/3D/4D co-culture systems with loss-of-function mutations in TREM2 (a frameshift mutation engineered in exon 2) brain organoids/microglia/assembloids, it is identified that the clearance of Aβ via TREM2 is accelerated by externalized phosphatidylserine (ePtdSer) generated from dystrophic neurons surrounding the Aβ plaques. Moreover, it is investigated whether microglia from both sporadic (CRISPR-Cas9-based APOE4 lines) and familial (APPNL-G-F/MAPT double knock-in mice) AD models show reduced levels of TREM2 and lack of phagocytic activity toward ePtdSer-positive Aβ plaques. Herein new insight is provided into TREM2-dependent microglial phagocytosis of Aβ plaques in the context of the presence of ePtdSer during AD progression.

Benchmarking and integrating human B-cell receptor genomic and antibody proteomic profiling

Immunoglobulins (Ig), which exist either as B-cell receptors (BCR) on the surface of B cells or as antibodies when secreted, play a key role in the recognition and response to antigenic threats. The capability to jointly characterize the BCR and antibody repertoire is crucial for understanding human adaptive immunity. From peripheral blood, bulk BCR sequencing (bulkBCR-seq) currently provides the highest sampling depth, single-cell BCR sequencing (scBCR-seq) allows for paired chain characterization, and antibody peptide sequencing by tandem mass spectrometry (Ab-seq) provides information on the composition of secreted antibodies in the serum. Yet, it has not been benchmarked to what extent the datasets generated by these three technologies overlap and complement each other. To address this question, we isolated peripheral blood B cells from healthy human donors and sequenced BCRs at bulk and single-cell levels, in addition to utilizing publicly available sequencing data. Integrated analysis was performed on these datasets, resolved by replicates and across individuals. Simultaneously, serum antibodies were isolated, digested with multiple proteases, and analyzed with Ab-seq. Systems immunology analysis showed high concordance in repertoire features between bulk and scBCR-seq within individuals, especially when replicates were utilized. In addition, Ab-seq identified clonotype-specific peptides using both bulk and scBCR-seq library references, demonstrating the feasibility of combining scBCR-seq and Ab-seq for reconstructing paired-chain Ig sequences from the serum antibody repertoire. Collectively, our work serves as a proof-of-principle for combining bulk sequencing, single-cell sequencing, and mass spectrometry as complementary methods towards capturing humoral immunity in its entirety.

Single cell transcriptome analysis identified a unique neutrophil type associated with Alzheimer's disease

BACKGROUND

Neutrophils play an essential role in Alzheimer's disease (AD) pathology. However, the extent of their heterogeneity remains poorly explored, particularly in the context of developing novel therapies targeting these cells.

RESULTS

We investigate the population structure of neutrophils purified from peripheral blood samples of AD mice. Utilizing single cell RNA sequencing, we comprehensively map neutrophil populations into six distinct clusters and find that the Neu-5 subset is specially enriched in AD mice. This subset exhibits fewer specific granules and a lower mature score. Gene ontology (GO) analysis reveals that genes involved in cytokine-mediated signaling are downregulated in the Neu-5 cluster. Furthermore, we identify the Ccrl2 gene is specifically upregulated in this subgroup, which is confirmed by flow cytometry in AD mice. Finally, immunohistochemical staining indicates that CCRL2 protein is increased in the brains of AD mice.

CONCLUSIONS

We identify a unique CCRL2 positive neutrophil cluster, that is specifically enriched in the peripheral blood of AD mice.

Neuroinflammation in Alzheimer's disease: insights from peripheral immune cells

Alzheimer's disease (AD) is a serious brain disorder characterized by the presence of beta-amyloid plaques, tau pathology, inflammation, neurodegeneration, and cerebrovascular dysfunction. The presence of chronic neuroinflammation, breaches in the blood-brain barrier (BBB), and increased levels of inflammatory mediators are central to the pathogenesis of AD. These factors promote the penetration of immune cells into the brain, potentially exacerbating clinical symptoms and neuronal death in AD patients. While microglia, the resident immune cells of the central nervous system (CNS), play a crucial role in AD, recent evidence suggests the infiltration of cerebral vessels and parenchyma by peripheral immune cells, including neutrophils, T lymphocytes, B lymphocytes, NK cells, and monocytes in AD. These cells participate in the regulation of immunity and inflammation, which is expected to play a huge role in future immunotherapy. Given the crucial role of peripheral immune cells in AD, this article seeks to offer a comprehensive overview of their contributions to neuroinflammation in the disease. Understanding the role of these cells in the neuroinflammatory response is vital for developing new diagnostic markers and therapeutic targets to enhance the diagnosis and treatment of AD patients.

The immunobiology of herpes simplex virus encephalitis and post-viral autoimmunity

Herpes simplex virus encephalitis (HSE) is the leading cause of non-epidemic encephalitis in the developed world and, despite antiviral therapy, mortality and morbidity is high. The emergence of post-HSE autoimmune encephalitis reveals a new immunological paradigm in autoantibody-mediated disease. A reductionist evaluation of the immunobiological mechanisms in HSE is crucial to dissect the origins of post-viral autoimmunity and supply rational approaches to the selection of immunotherapeutics. Herein, we review the latest evidence behind the phenotypic progression and underlying immunobiology of HSE including the cytokine/chemokine environment, the role of pathogen-recognition receptors, T- and B-cell immunity and relevant inborn errors of immunity. Second, we provide a contemporary review of published patients with post-HSE autoimmune encephalitis from a combined cohort of 110 patients. Third, we integrate novel mechanisms of autoimmunization in deep cervical lymph nodes to explore hypotheses around post-HSE autoimmune encephalitis and challenge these against mechanisms of molecular mimicry and others. Finally, we explore translational concepts where neuroglial surface autoantibodies have been observed with other neuroinfectious diseases and those that generate brain damage including traumatic brain injury, ischaemic stroke and neurodegenerative disease. Overall, the clinical and immunological landscape of HSE is an important and evolving field, from which precision immunotherapeutics could soon emerge.

Building Representation Learning Models for Antibody Comprehension

Antibodies are versatile proteins with both the capacity to bind a broad range of targets and a proven track record as some of the most successful therapeutics. However, the development of novel antibody therapeutics is a lengthy and costly process. It is challenging to predict the functional and biophysical properties of antibodies from their amino acid sequence alone, requiring numerous experiments for full characterization. Machine learning, specifically deep representation learning, has emerged as a family of methods that can complement wet lab approaches and accelerate the overall discovery and engineering process. Here, we review advances in antibody sequence representation learning, and how this has improved antibody structure prediction and facilitated antibody optimization. We discuss challenges in the development and implementation of such models, such as the lack of publicly available, well-curated antibody function data and highlight opportunities for improvement. These and future advances in machine learning for antibody sequences have the potential to increase the success rate in developing new therapeutics, resulting in broader access to transformative medicines and improved patient outcomes.

Distinct features of B cell receptors in neuromyelitis optica spectrum disorder among CNS inflammatory demyelinating diseases

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) stands out among CNS inflammatory demyelinating diseases (CIDDs) due to its unique disease characteristics, including severe clinical attacks with extensive lesions and its association with systemic autoimmune diseases. We aimed to investigate whether characteristics of B cell receptors (BCRs) differ between NMOSD and other CIDDs using high-throughput sequencing.

METHODS

From a prospective cohort, we recruited patients with CIDDs and categorized them based on the presence and type of autoantibodies: NMOSD with anti-aquaporin-4 antibodies, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) with anti-myelin oligodendrocyte glycoprotein antibodies, double-seronegative demyelinating disease (DSN), and healthy controls (HCs). The BCR features, including isotype class, clonality, somatic hypermutation (SHM), and the third complementarity-determining region (CDR3) length, were analyzed and compared among the different disease groups.

RESULTS

Blood samples from 33 patients with CIDDs (13 NMOSD, 12 MOGAD, and 8 DSN) and 34 HCs were investigated for BCR sequencing. Patients with NMOSD tended to have more activated BCR features compare to the other disease groups. They showed a lower proportion of unswitched isotypes (IgM and IgD) and a higher proportion of switched isotypes (IgG), increased clonality of BCRs, higher rates of SHM, and shorter lengths of CDR3. Notably, advanced age was identified as a clinical factor associated with these activated BCR features, including increased levels of clonality and SHM rates in the NMOSD group. Conversely, no such clinical factors were found to be associated with activated BCR features in the other CIDD groups.

CONCLUSIONS

NMOSD patients, among those with CIDDs, displayed the most pronounced B cell activation, characterized by higher levels of isotype class switching, clonality, SHM rates, and shorter CDR3 lengths. These findings suggest that B cell-mediated humoral immune responses and characteristics in NMOSD patients are distinct from those observed in the other CIDDs, including MOGAD. Age was identified as a clinical factor associated with BCR activation specifically in NMOSD, implying the significance of persistent B cell activation attributed to anti-aquaporin-4 antibodies, even in the absence of clinical relapses throughout an individual's lifetime.

Immune-related signature of periodontitis and Alzheimer's disease linkage

Background: Periodontits (PD) and Alzheimer's disease (AD) are both associated with ageing and clinical studies increasingly evidence their association. However, specific mechanisms underlying this association remain undeciphered, and immune-related processes are purported to play a signifcant role. The accrual of publicly available transcriptomic datasets permits secondary analysis and the application of data-mining and bioinformatic tools for biological discovery. Aim: The present study aimed to leverage publicly available transcriptomic datasets and databases, and apply a series of bioinformatic analysis to identify a robust signature of immune-related signature of PD and AD linkage. Methods: We downloaded gene-expresssion data pertaining PD and AD and identified crosstalk genes. We constructed a protein-protein network analysis, applied immune cell enrichment analysis, and predicted crosstalk immune-related genes and infiltrating immune cells. Next, we applied consisent cluster analysis and performed immune cell bias analysis, followed by LASSO regression to select biomarker immune-related genes. Results: The results showed a 3 gene set comprising of DUSP14, F13A1 and SELE as a robust immune-related signature. Macrophages M2 and NKT, B-cells, CD4+ memory T-cells and CD8+ naive T-cells emerged as key immune cells linking PD with AD. Conclusion: Candidate immune-related biomarker genes and immune cells central to the assocation of PD with AD were identified, and merit investigation in experimental and clinical research.

Current views on meningeal lymphatics and immunity in aging and Alzheimer's disease

Alzheimer's disease (AD) is an aging-related form of dementia associated with the accumulation of pathological aggregates of amyloid beta and neurofibrillary tangles in the brain. These phenomena are accompanied by exacerbated inflammation and marked neuronal loss, which altogether contribute to accelerated cognitive decline. The multifactorial nature of AD, allied to our still limited knowledge of its etiology and pathophysiology, have lessened our capacity to develop effective treatments for AD patients. Over the last few decades, genome wide association studies and biomarker development, alongside mechanistic experiments involving animal models, have identified different immune components that play key roles in the modulation of brain pathology in AD, affecting its progression and severity. As we will relay in this review, much of the recent efforts have been directed to better understanding the role of brain innate immunity, and particularly of microglia. However, and despite the lack of diversity within brain resident immune cells, the brain border tissues, especially the meninges, harbour a considerable number of different types and subtypes of adaptive and innate immune cells. Alongside microglia, which have taken the centre stage as important players in AD research, there is new and exciting evidence pointing to adaptive immune cells, namely T and B cells found in the brain and its meninges, as important modulators of neuroinflammation and neuronal (dys)function in AD. Importantly, a genuine and functional lymphatic vascular network is present around the brain in the outermost meningeal layer, the dura. The meningeal lymphatics are directly connected to the peripheral lymphatic system in different mammalian species, including humans, and play a crucial role in preserving a "healthy" immune surveillance of the CNS, by shaping immune responses, not only locally at the meninges, but also at the level of the brain tissue. In this review, we will provide a comprehensive view on our current knowledge about the meningeal lymphatic vasculature, emphasizing its described roles in modulating CNS fluid and macromolecule drainage, meningeal and brain immunity, as well as glial and neuronal function in aging and in AD.

Sex-based differences in effector cells of the adaptive immune system during Alzheimer's disease and related dementias

Neurological conditions such as Alzheimer's disease (AD) and related dementias (ADRD) present with many challenges due to the heterogeneity of the related disease(s), making it difficult to develop effective treatments. Additionally, the progression of ADRD-related pathologies presents differently between men and women. With two-thirds of the population affected with ADRD being women, ADRD has presented itself with a bias toward the female population. However, studies of ADRD generally do not incorporate sex-based differences in investigating the development and progression of the disease, which is detrimental to understanding and treating dementia. Additionally, recent implications for the adaptive immune system in the development of ADRD bring in new factors to be considered as part of the disease, including sex-based differences in immune response(s) during ADRD development. Here, we review the sex-based differences of pathological hallmarks of ADRD presentation and progression, sex-based differences in the adaptive immune system and how it changes with ADRD, and the importance of precision medicine in the development of a more targeted and personalized treatment for this devastating and prevalent neurodegenerative condition.