Search Results (134)

Elevated sodium concentrations are commonly observed in tumors and sites of inflammation. Previous studies have shown that high salt levels modulate the phenotype and function of CD4⁺ and CD8⁺ T cells, regulatory T cells, and macrophages. In this study, we performed transcriptomic studies that revealed profound alterations in the neutrophil transcriptome upon high salt exposure, with changes that significantly exceeded those triggered by conventional agonists. By integrating transcriptomic data with functional assays, our findings suggest that high salt-induced neutrophil activation involves mitochondrial ROS production, which subsequently activates p38 MAPK and engages FOS-, Bruton’s tyrosine kinase (BTK)-, and cyclooxygenase 2 (COX2)-dependent pathways. Remarkably, the plasticity of the neutrophil transcriptome in response to high salt was further evidenced by the upregulation of genes typically associated with other cell types, including semenogelin 1 (SEMG1), intercellular adhesion molecule-4 (ICAM4), tripartite motif69 (TRIM69), amphiregulin (AREG), oncostatin (OSM), and transducer of ERBB2-1 (TOB1), suggesting a broader role for neutrophils in different biological processes beyond their participation in innate immunity. Full article

BTK (Bruton’s tyrosine kinase) has become a key therapeutic target across several hematologic diseases, beginning with its original use in CLL/SLL. As a central mediator of B-cell receptor signaling and microenvironment interactions, BTK supports survival, proliferation, and trafficking in multiple mature B-cell malignancies (mantle cell lymphoma, marginal zone lymphoma, Waldenström macroglobulinemia, and other indolent/aggressive lymphomas) and in selected immune-mediated conditions such as chronic graft-versus-host disease. Covalent BTK inhibitors (ibrutinib, acalabrutinib, and zanubrutinib) irreversibly bind the C481 residue and have produced high response rates and durable disease control, often replacing chemoimmunotherapy in the relapsed setting and, for some entities, even in the first line. Differences in kinase selectivity lead to different safety profiles: second-generation covalent agents generally maintain efficacy while reducing significant off-target toxicities, especially atrial fibrillation and hypertension. Resistance to covalent BTK inhibitors most commonly develops through BTK C481 substitutions and activating PLCG2 mutations, with other kinase-domain variants increasingly recognized. Non-covalent BTK inhibitors (e.g., pirtobrutinib) bind BTK independently of C481, can overcome classic C481-mediated resistance, and extend BTK pathway targeting into later lines of therapy. Overall, BTK inhibition has evolved into a versatile platform enabling long-term, often chemo-free management strategies. Full article

Multiple sclerosis (MS) is a heterogeneous autoimmune disease driven by peripheral immune dysregulation and compartmentalized central nervous system (CNS) inflammation. Despite more than 20 approved disease-modifying therapies, disability accrual remains common, particularly in patients with highly active relapsing disease and progressive phenotypes characterized by silent progression and smoldering neuroinflammation. Two emerging therapeutic strategies address these unmet needs: Bruton’s tyrosine kinase (BTK) inhibitors and autologous haematopoietic stem cell transplantation (HSCT). Although mechanistically distinct, both aim to overcome limitations of conventional immunosuppression by intervening more deeply in the autoimmune cascade. This narrative review synthesized mechanistic, clinical, and translational evidence identified through a comprehensive search of PubMed, Scopus, Web of Science, and ClinicalTrials.gov from January 2010 to August 2025. BTK inhibitors are oral, CNS-penetrant therapies that selectively modulate B-cell signaling and CNS-resident myeloid cells without broad lymphocyte depletion, enabling continuous immunomodulation. Phase II–III trials of evobrutinib, tolebrutinib, and fenebrutinib show consistent MRI activity suppression but variable effects on relapses and disability, suggesting relevance in microglial-driven, relapse-independent disease. HSCT is a one-time immune reconstitution therapy that eradicates autoreactive immune clones and restores immune tolerance. Randomized and real-world studies demonstrate profound suppression of inflammatory activity, stabilization or improvement of disability, and durable treatment-free remission in selected patients with highly active relapsing–remitting MS, although procedure-related risks require strict eligibility criteria and experienced centers. Together with BTK inhibitors, HSCT represents a complementary strategy within an increasingly personalized MS treatment paradigm, emphasizing biomarker-guided patient selection and optimized therapeutic sequencing. Full article

Ibrutinib (IB), a Bruton’s tyrosine kinase (BTK) inhibitor, is widely used against B-cell malignancies. However, its adverse effects on stem cell-dependent processes and tissue homeostasis remain incompletely understood. Freshwater planarians possess pluripotent stem cells (neoblasts), which enable remarkable regeneration of various tissues, including the central nervous system. This makes them ideal in vivo models for studying chemical toxicity within a whole-organism context. Here, we utilized planarian Dugesia constrictiva to assess IB toxicity and elucidate its mechanisms, focusing on its impact on stem cell dynamics and regeneration. Our results demonstrated that exposure to IB at concentrations as low as 0.9 mg/L, far below clinical plasma levels, led to severe morphological and regenerative impairments, including disrupted neural regeneration. Mechanistically, IB disrupted stem cell dynamics by suppressing proliferation and differentiation and by inducing oxidative stress via ROS overproduction. Notably, IB exposure significantly downregulated BTK expression. Crucially, BTK RNAi caused the key toxic effects of IB exposure, including morphological and regenerative defects, suppression of stem cell proliferation and differentiation, and increased apoptosis. Therefore, we conclude that IB may exert its toxicity in planarians primarily through BTK inhibition. This finding provides direct functional evidence linking BTK inhibition to stem cell dysfunction and regenerative defects in a novel in vivo context, offering critical insights for refining the clinical safety profile of IB. Full article

Belimumab, a fully humanized B cell-activating factor (BAFF)-targeting monoclonal antibody, inhibits autoreactive B cell survival and improves systemic lupus erythematosus (SLE) clinical outcomes. However, its administration criteria remain unclear. To establish a basis for defining these criteria, we characterized the immune cell subpopulation alterations post-belimumab treatment and elucidated the underlying mechanisms. We hypothesized that belimumab modulates specific cell subsets and investigated the post-therapy changes. Flow cytometry and correlation analysis revealed that the frequency of B- and T-lymphocyte attenuator (BTLA)^high memory B cells in peripheral blood and clinical improvement after belimumab treatment. Western blotting analysis of healthy control B cells revealed that BTLA engagement suppressed Bruton tyrosine kinase and phospholipase C-gamma 2 phosphorylation, which was enhanced by B cell and BAFF receptor co-stimulation. BTLA-expressing memory B cells, which positively correlate with disease improvement, possibly contributed to SLE improvement via BTLA-mediated signaling that attenuated B cell- and BAFF receptor-induced intracellular pathways. To validate these findings, we plan to further assess the effects of belimumab on BTLA expression and B cell signaling pathways in treatment-naive patients with SLE by western blotting. Collectively, our results provide a novel foundation for establish appropriate belimumab administration criteria. Full article

Over the past decade, chronic lymphocytic leukaemia (CLL) treatment has shifted from chemoimmunotherapy to targeted oral agents, predominantly Bruton’s tyrosine kinase inhibitors (BTKis) and the BCL-2 inhibitor venetoclax. These therapies have significantly improved outcomes and are now established as first-line treatment options. However, CLL remains incurable, and resistance or intolerance to both drug classes (double-refractory disease) is an emerging challenge. This has driven the development of novel therapeutic strategies, including non-covalent BTKis such as pirtobrutinib and nemtabrutinib, which retain activity in BTK C481-mutated disease. Next-generation BCL-2 inhibitors (sonrotoclax, lisaftoclax) and BTK degraders are promising in early clinical trials. Immunotherapeutic approaches, such as bispecific T-cell engagers, CD20/CD3 antibodies, and CAR-T cell therapies, provide additional options for high-risk patients. Although PI3K inhibitors remain under investigation, their role is yet to be defined due to safety concerns. Minimal residual disease (MRD)-guided, fixed-duration regimens represent a significant paradigm shift toward personalised treatment and potentially deeper remissions. Ongoing clinical studies are expected to introduce new effective therapies that may further transform the management of CLL in the coming years. Full article

Bing–Neel syndrome (BNS), a rare complication of Waldenström macroglobulinemia (WM), is caused by the direct infiltration of lymphoplasmacytic cells into the central nervous system (CNS). Since clinical manifestations are heterogeneous and may overlap with IgM-related neuropathies, BNS is often under-recognized and diagnosed late. The incidence of BNS has been reported to be approximately 1% of patients with WM. Because of its extreme rarity, there are no prospective studies on BNS. In 2025, a consensus panel from the 12th international workshop on WM updated the guidelines for BNS, recognizing zanubrutinib as a standard therapy, clarifying imaging and cerebrospinal fluid (CSF) assessments during follow-up, and introducing revised response categories. Although the incidence of BNS is approximately 1% of WM, it decreases overall survival compared to WM alone, and early deaths were reported in historical series. Diagnostic confirmation requires a high index of suspicion and a multimodal approach combining MRI of the brain and spine with gadolinium, CSF cytology and flow cytometry, molecular testing such as MYD88 L265P, and occasionally tissue biopsy. Importantly, MYD88 L265P is also observed in most cases of diffuse large B-cell lymphoma of the CNS and is therefore not disease-specific. Differentiation from IgM-mediated neuropathies is critical because management strategies markedly differ. Historically, high-dose methotrexate- or cytarabine-based chemotherapy, intrathecal therapy, and radiotherapy have been used; however, responses varied, and toxicity was considerable. In contrast, CNS-penetrant Bruton tyrosine kinase (BTK) inhibitors have reshaped therapeutic strategies. Retrospective data support durable responses with ibrutinib, tirabrutinib, and zanubrutinib, while early findings suggest that non-covalent BTK inhibitors expand options for relapsed or refractory cases. Herein, we synthesize current evidence on epidemiology, pathophysiology, and diagnostic work-up. We also outline therapeutic recommendations integrating the genotype, disease pattern, and patient fitness and conclude with unmet needs and future directions. Full article

Background: Multiple sclerosis is a multifactorial neurodegenerative disease characterized by autoimmune and inflammatory processes. Despite advancements in disease-modifying therapies, multiple sclerosis remains challenging due to its complex pathophysiology and variable clinical presentation. Current therapies focus on managing inflammation and promoting immunosuppression but do not achieve complete symptom regression or enhance remyelination. Emerging therapies, such as Peroxisome Proliferator-Activated Receptor gamma (PPARγ) agonists and Bruton tyrosine kinase (BTK) inhibitors, show promise in modulating inflammation and targeting immune cells. Innovative approaches like human fetal neural precursor cells (hfPNCs) and mesenchymal stem cell transplantation are being explored to reduce neural inflammation and improve neuroprotection. Early diagnosis and intervention are crucial for managing multiple sclerosis effectively and preventing progression to severe forms and permanent disability. Therapeutic education for individuals with multiple sclerosis and their caregivers is essential, emphasizing the need for clear, reliable information to support disease management and improve quality of life. Objectives: This review provides an up-to-date overview of multiple sclerosis pathophysiology, current treatments, and emerging therapies, aiming to enhance the knowledge base of healthcare professionals and researchers, facilitating informed decision-making and contributing to ongoing research efforts. Full article

Background/Objectives: Covalent Bruton’s tyrosine kinase (BTK) inhibitors (ibrutinib, acalabrutinib, zanubrutinib) improve outcomes in advanced chronic lymphocytic leukemia (CLL) but resistance, largely driven by BTK C481 mutations, and adverse events limit long-term benefit. Noncovalent BTK inhibitors (e.g., pirtobrutinib) reversibly inhibit the BTK ATP-binding pocket independent of C481, potentially overcoming resistance and reducing toxicity. This review summarizes clinical evidence for pirtobrutinib in CLL. Methods: A PubMed search of articles through July 2025 was conducted, focusing on clinical trials of pirtobrutinib. We extracted efficacy, safety, and resistance data, emphasizing the BRUIN CLL-321 phase 3 trial and related studies. Results: Pirtobrutinib demonstrates activity against BTK resistance mutations with a favorable safety profile, partly due to high kinase selectivity. In BRUIN CLL-321, pirtobrutinib achieved an overall response rate (ORR) of 62% and a median progression-free survival (PFS) of 20 months in heavily pretreated patients, including those with resistance mutations. Yet, resistance mechanisms—such as alternative pathway activation and additional BTK mutations—emerge in a subset. Baseline genetic features, including BTK mutation status and cytogenetics, influence response durability and outcomes. Ongoing phase 3 trials comparing pirtobrutinib with covalent BTK inhibitors will clarify its potential as a first-line option and its integration into treatment algorithms. In relapsed/refractory CLL, noncovalent BTK inhibitors may be incorporated into personalized pathways, including bridging to CAR-T therapy, to optimize long-term disease control. Conclusions: Pirtobrutinib offers a promising strategy to address resistance and potentially improve durable disease control in CLL. Definitive trials will define its role relative to covalent BTK inhibitors and its utility across treatment lines within personalized, multimodal regimens. Full article

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in Western populations and remains incurable despite significant therapeutic advancements. Over the past decade, the treatment landscape has evolved from traditional chemoimmunotherapy to targeted oral agents, including Bruton’s tyrosine kinase inhibitors (BTKis) and BCL2 inhibitors (BCL2is), which have demonstrated superior efficacy and tolerability, especially in elderly patients. Venetoclax, a BCL2i, induces apoptosis in CLL cells through selective inhibition of the anti-apoptotic BCL2 protein, while BTKis, such as ibrutinib and its next-generation analogs, disrupt B-cell receptor signaling critical to CLL cell survival. However, resistance to both drug classes has emerged, including mutations in BTK and BCL2, prompting the exploration of novel therapeutic strategies. This review outlines the molecular basis and clinical implications of these resistance mechanisms, as well as emerging therapeutic solutions, including non-covalent BTKis like pirtobrutinib and BTK-targeting PROTAC degraders such as BGB-16673 and NX-2127. Additionally, we discuss promising combination therapies incorporating BTKis, BCL2is, and anti-CD20 monoclonal antibodies. Finally, we highlight the growing role of measurable residual disease (MRD) as a biomarker to guide treatment duration and evaluate therapeutic success. As resistance mechanisms continue to emerge, tailoring therapy based on underlying biology will be critical to sustaining disease control and enhancing outcomes in patients with CLL. Full article

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. It is characterized by the clonal proliferation of mature B cells. The tumor microenvironment (TME) seems to play a crucial role in the survival and proliferation of tumor cells. Multiple new classes of drugs had been approved for the management of patients with CLL, reshaping the treatment paradigm. The most important classes are Bruton’s tyrosine kinase (BTK) inhibitors and BCL-2 inhibitors. Both of them are approved as a first-line treatment in patients with CLL requiring treatment. The role of BTK and BCL-2 in the signaling pathways of the TME is very important. The aim of this review is to summarize the major components of the TME and the available data regarding targeted therapies in CLL. Full article

Bruton Tyrosine Kinase (BTK) has emerged as a critical mediator in the pathophysiology of neuroinflammation associated with neurodegenerative diseases. BTK, a non-receptor tyrosine kinase predominantly expressed in cells of the hematopoietic lineage, modulates B-cell receptor signaling and innate immune responses, including microglial activation. Recent evidence implicates aberrant BTK signaling in the exacerbation of neuroinflammatory cascades contributing to neuronal damage in disorders such as Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, ischemic stroke, and Huntington’s disease. Pharmacological inhibition of BTK has shown promise in attenuating microglial-mediated neurotoxicity, reducing pro-inflammatory cytokine release, and promoting neuroprotection in preclinical models. BTK inhibitors, originally developed for hematological malignancies, demonstrate favorable blood–brain barrier penetration and immunomodulatory effects relevant to central nervous system pathology. This therapeutic approach may counteract detrimental neuroimmune interactions without broadly suppressing systemic immunity, thus preserving host defense. Ongoing clinical trials are evaluating the safety and efficacy of BTK inhibitors in patients with neurodegenerative conditions, with preliminary results indicating potential benefits in slowing disease progression and improving neurological outcomes. This review consolidates current knowledge on BTK signaling in neurodegeneration and highlights the rationale for BTK inhibition as a novel, targeted therapeutic strategy to modulate neuroinflammation and mitigate neurodegenerative processes. Full article

Pediatric-onset multiple sclerosis (POMS) is a rare yet increasingly recognized demyelinating disease of the central nervous system, characterized by a highly inflammatory disease course and an elevated relapse rate compared to adult-onset MS (AOMS). Given the unique immunopathogenesis of POMS, recent therapeutic strategies have shifted toward early initiation of high-efficacy disease-modifying therapies (DMTs) to minimize irreversible neurological damage. Among these, B-cell-targeting therapies, particularly anti-CD20 monoclonal antibodies, have shown efficacy in adult MS and are emerging as promising candidates for POMS treatment. The present review summarizes the current knowledge of the role of B-cells in POMS pathophysiology and evaluates the therapeutic potential of anti-CD-20 agents. It also highlights ongoing clinical trials and future perspectives, including novel B-cell-directed approaches such as anti-CD19 therapies, Bruton’s tyrosine kinase (BTK) inhibitors, and BAFF-targeting agents. Full article

Chronic Lymphocytic Leukemia (CLL) is a highly heterogeneous tumor. Although targeted therapies such as Bruton’s Tyrosine Kinase (BTK) inhibitors and B-cell lymphoma-2 (Bcl-2) inhibitors have significantly improved patient outcomes in CLL, the disease remains incurable. A critical aspect of CLL progression is its transformation from an indolent tumor to a high-grade malignancy, a process known as Richter’s Transformation (RT) or Richter Syndrome. Treatment options for RT are very limited, and patient prognosis is often poor. The molecular mechanisms driving RT are not yet fully elucidated. This review aims to summarize recent advances in research aimed at uncovering the mechanisms underlying RT in CLL. By integrating findings from genetics, signaling pathways, epigenetics, and the tumor microenvironment, this review seeks to provide insights that could guide further basic research into RT and inform the development of novel therapeutic strategies to improve patient outcomes. Full article

Bruton’s tyrosine kinase (BTK) is a key signaling molecule involved in both hematological malignancies and solid tumors. In B-cell malignancies such as chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), BTK mediates B-cell receptor signaling, promoting tumor survival and proliferation, leading to the development of BTK inhibitors like ibrutinib that improve patient outcomes. In solid tumors, BTK isoforms, particularly p65BTK, contribute to tumor growth and therapy resistance, with inhibition showing promise in cancers like colorectal, ovarian, and non-small cell lung cancer. BTK also influences the tumor microenvironment by modulating immune cells such as myeloid-derived suppressor cells and tumor-associated macrophages, aiding immune evasion. BTK inhibition can enhance anti-tumor immunity and reduce inflammation-driven tumor progression. Additionally, BTK contributes to tumor angiogenesis, with inhibitors like ibrutinib showing anti-angiogenic effects. Beyond cancer, BTK is linked to aging, where its modulation may reduce senescent cell accumulation and preserve cognitive function. This review explores BTK’s dual role, focusing on its oncogenic effects and potential impact on aging processes. We also discuss the use of BTK inhibitors in cancer treatment and their potential to address age-related concerns, providing a deeper understanding of BTK as a therapeutic target and mediator in the complex relationship between cancer and aging. Full article