Lymphoid Organs Research Articles

The malignant transformation potential of the oncogene STYK1/NOK at early lymphocyte development in transgenic mice

B-cell Chronic Lymphocytic Leukemia (B-CLL) is a malignancy caused by the clonal expansion of mature B lymphocytes bearing a CD5+CD19+ (B1) phenotype. However, the origin of B-CLL remains controversial. We showed previously that STYK1/NOK transgenic mice develop a CLL-like disease. Using this model system in this study, we attempt to define the stage of CLL initiation. Here, we show that the phenotype of STYK1/NOK-induced B-CLL is heterogeneous. The expanded B1 lymphocyte pool was detected within peripheral lymphoid organs and was frequently associated with the expansions of memory B cells. Despite this immunophenotypic heterogeneity, suppression of B cell development at an early stage consistently occurred within the bone marrow (BM) of STYK1/NOK-tg mice. Overall, we suggest that enforced expression of STYK1/NOK in transgenic mice might significantly predispose BM hematopoietic stem cells (HSCs) towards the development of B-CLL.

Chitin-mediated blockade of chitinase-like proteins reduces tumor immunosuppression, inhibits lymphatic metastasis and enhances anti-PD-1 efficacy in complementary TNBC models

BackgroundChitinase-like proteins (CLPs) play a key role in immunosuppression under inflammatory conditions such as cancer. CLPs are enzymatically inactive and become neutralized upon binding of their natural ligand chitin, potentially reducing CLP-driven immunosuppression. We investigated the efficacy of chitin treatment in the context of triple-negative breast cancer (TNBC) using complementary mouse models. We also evaluated the immunomodulatory influence of chitin on immune checkpoint blockade (ICB) and compared its efficacy as general CLP blocker with blockade of a single CLP, i.e. chitinase 3-like 1 (CHI3L1).MethodsFemale BALB/c mice were intraductally injected with luciferase-expressing 4T1 or 66cl4 cells and systemically treated with chitin in combination with or without anti-programmed death (PD)-1 ICB. For single CLP blockade, tumor-bearing mice were treated with anti-CHI3L1 antibodies. Metastatic progression was monitored through bioluminescence imaging. Immune cell changes in primary tumors and lymphoid organs (i.e. axillary lymph nodes and spleen) were investigated through flow cytometry, immunohistochemistry, cytokine profiling and RNA-sequencing. CHI3L1-stimulated RAW264.7 macrophages were subjected to 2D lymphatic endothelial cell adhesion and 3D lymphatic integration in vitro assays for studying macrophage-mediated lymphatic remodeling.ResultsChitin significantly reduced primary tumor progression in the 4T1-based model by decreasing the high production of CLPs that originate from tumor-associated neutrophils (TANs) and Stat3 signaling, prominently affecting the CHI3L1 and CHI3L3 primary tumor levels. It reduced immunosuppressive cell types and increased anti-tumorigenic T-cells in primary tumors as well as axillary lymph nodes. Chitin also significantly reduced CHI3L3 primary tumor levels and immunosuppression in the 66cl4-based model. Compared to anti-CHI3L1, chitin enhanced primary tumor growth reduction and anti-tumorigenicity. Both treatments equally inhibited lymphatic adhesion and integration of macrophages, thereby hampering lymphatic tumor cell spreading. Upon ICB combination therapy, chitin alleviated anti-PD-1 resistance in both TNBC models, providing a significant add-on reduction in primary tumor and lung metastatic growth compared to chitin monotherapy. These add-on effects occurred through additional increase in CD8α+ T-cell infiltration and activation in primary tumor and lymphoid organs.ConclusionsChitin, as a general CLP blocker, reduces CLP production, enhances anti-tumor immunity as well as ICB responses, supporting its potential clinical relevance in immunosuppressed TNBC patients.

Neuroretinal degeneration in a mouse model of systemic chronic immune activation observed by proteomics.

Blindness or vision loss due to neuroretinal and photoreceptor degeneration affects millions of individuals worldwide. In numerous neurodegenerative diseases, including age-related macular degeneration, dysregulated immune response-mediated retinal degeneration has been found to play a critical role in the disease pathogenesis. To better understand the pathogenic mechanisms underlying the retinal degeneration, we used a mouse model of systemic immune activation where we infected mice with lymphocytic choriomeningitis virus (LCMV) clone 13. Here, we evaluated the effects of LCMV infection and present a comprehensive discovery-based proteomic investigation using tandem mass tag (TMT) labeling and high-resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS). Changes in protein regulation in the posterior part of the eye, neuroretina, and RPE/choroid were compared to those in the spleen as a secondary lymphoid organ and to the kidney as a non-lymphoid but encapsulated organ at 1, 8, and 28 weeks of infection. Using bioinformatic tools, we found several proteins responsible for maintaining normal tissue homeostasis to be differentially regulated in the neuroretina and the RPE/choroid during the degenerative process. Additionally, in the organs we observed, several important protein pathways contributing to cellular homeostasis and tissue development were perturbed and associated with LCMV-mediated inflammation, promoting disease progression. Our findings suggest that the response to a systemic chronic infection differs between the neuroretina and the RPE/choroid, and the processes induced by chronic systemic infection in the RPE/choroid are not unlike those induced in non-immune-privileged organs such as the kidney and spleen. Overall, our data provide detailed insight into several molecular mechanisms of neuroretinal degeneration and highlight various novel protein pathways that further suggest that the posterior part of the eye is not an isolated immunological entity despite the existence of neuroretinal immune privilege.

Immune profiling of responses to influenza vaccination in patients with myeloproliferative neoplasms.

Myeloproliferative neoplasms (MPNs) are associated with immune dysregulation and increased susceptibility to infection, emphasizing the importance of vaccination for patients. This pilot study evaluated immune responses to influenza vaccination in MPN patients compared with healthy donors using mass cytometry and serology. We observed diminished CXCR5+ B-cell, CXCR3+ T-cell, activated CD127+ memory T-cell subsets, and a trend toward lower hemagglutinin inhibition titer in MPN patients. These results indicate that patients with MPN exhibit distinct responses to influenza vaccination suggestive of impaired migration to lymphoid organs and T-cell maturation which may impact the development of protective immunity.

Abstract CT108: Phase I data from TENDU101, a first-in-human trial of a novel synthetic peptide conjugate cancer vaccine platform assessed in recurrent prostate cancer patients before salvage treatment

Abstract Synthetic peptides are explored in the clinic in cancer vaccine development for the purpose of inducing tumor-directed T cell responses. Their immunogenicity is dependent on the chosen adjuvant and target organ exposure (lymphoid organs). To improve peptide immunogenicity, we have developed a technology enabling cross-linking of endogenous, pre-existing circulating antibodies (Abs) by employing a three-dimensional chemistry design. Multiple identical tetanus toxin-derived B cell epitopes (MTTEs) are conjugated to synthetically made antigenic tumor peptides intended to induce T cell responses. Here we report the first clinical safety assessment of the vaccine platform in the trial TENDU101 (NCT04701021). The cancer vaccine candidate (TENDU) was designed to include longer synthetic peptides harboring prostate cancer derived epitopes (CD4 and CD8) from PAP and PSMA. The study was a 3+3 design and doses were 40, 400 and 960 microgram in patients with documented recurrent disease after radical prostatectomy. A tetanus toxoid (TTd) containing vaccine boost was followed by TENDU vaccination via subcutaneous injection in the abdomen (4 doses in total with a 2 week interval) in n=9 patients (gr 1, 2, 3.1). For group 3.2 (n=3) TENDU vaccination was administrated in the same arm as the TTd vaccination. Primary objective was safety and secondary objective assessment of immune responses and preliminary anti-tumor responses. A total of 52 adverse events (AEs) were reported, most mild and deemed unrelated to vaccination. Six treatment-related AEs were reported of which 50% were mild transient injection site reactions in a single patient (gr 3.1), and three events of increases in lipase levels in two patients (gr 2). No serious AEs was reported. T cell responses pre/post TENDU were assessed in a total of six patients of which five patients displayed increased response against vaccine-related CD8 and CD4 epitopes (ELISpot). The three patients with the greatest increase in T cell responses were found to display the highest anti-MTTE IgG responses. A trend towards decrease in circulating tumor cells from screening to the end of treatment visit was observed in the patients with the highest levels of anti-MTTE IgGs post TENDU vaccination. There were no trends for decrease in PSA and/or PAP at the end of treatment and follow-up measurements were affected by initiation of radiation and short-term androgen deprivation. The administration of TTd and TENDU to the same anatomical location although spaced in time appeared to negatively influence immune responses to TTd and TENDU. In conclusion, the novel synthetic peptide conjugate vaccine conjugate was found safe with no serious AEs reported and a positive correlation between anti-MTTE and T cell responses was noted in patients when TENDU was administrated in the abdomen. Citation Format: Wolfgang Lilleby, Anna Bergqvist, Aikaterini Nasi, Wenche Rasch, Sara Mangsbo. Phase I data from TENDU101, a first-in-human trial of a novel synthetic peptide conjugate cancer vaccine platform assessed in recurrent prostate cancer patients before salvage treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT108.

Abstract LB236: Metabolically armed CD19 CAR-T cells for safe and effective treatment of relapsed or refractory CD19+ B cell hematological malignancies at extremely low doses

Abstract Background: The undeniable success of CD19 CAR-T cell therapy in managing relapsed or refractory (r/r) B-cell hematological malignancies, such as diffuse large B-cell lymphoma (DLBCL) and B-cell acute lymphoblastic leukemia (B-ALL), underscores its significance. Despite the favorable complete remission (CR) rates of around 50% for r/r DLBCL and up to 90% for r/r B-ALL, a notable challenge persists as more than half of patients experiencing CR after CD19 CAR-T cells treatment encounter relapse within a year, attributed to inadequate CAR-T persistence in both indications. Urgent attention is required to devise innovative strategies to overcome these challenges. Recently, we developed metabolically armed CD19 CAR-T cells expressing IL-10 can enhance OXPHOS metabolism, proliferation, and persistence of CAR-T cells in vivo. Significantly, these IL-10-expressing CAR-T cells trigger stem-like memory responses in various lymphoid organs, leading to robust tumor eradication and durable protection. Motivated by these promising findings, an open-label, single arm, investigator-initiated trial (IIT, ClinicalTrials.gov identifier: NCT05715606, NCT05747157) was conducted to assess the safety and efficacy of newly developed metabolically armed IL-10-expressing CD19 CAR-T (product name: Meta10-19 infusion) for treating patients with r/r DLBCL or r/r B-ALL. Method: From Feb 2023 to Dec 2023, this IIT clinical trial evaluated Meta10-19 infusion in adult patients with r/r DLBCL or r/r B-ALL. The patients were recruited and treated at the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China. Patients in 3 dose cohorts (2.0 × 104, 5.0 × 104, or 1.0 × 105 CAR-T cells/kg, corresponding to 1%, 2.5%, or 5% doses of commercialized CAR-T infusion) underwent lymphodepleting chemotherapy with cyclophosphamide and fludarabine before Meta10-19 infusion. The primary endpoint was the incidence of dose-limiting toxicities. The secondary endpoint was the response and survival. Results: The treatment with Meta10-19 infusion has successfully induced CR in all 12 cases of r/r DLBCL (n=6) or r/r B-ALL (n=6), as evaluated by PET-CT scan, NMR spectroscopy or minimal residual disease assessment of bone marrow. No server cytokine storm syndrome or neurotoxicity was observed. All treated patients achieved CR at 3 months post treatment, with the first patient maintaining continuous remission up to 9 months until now. Notably, these metabolically armed CD19 CAR-T cells demonstrated efficacy even for patients with bulky mass (≥7.5 cm) of DLBCL at extremely low infusion dose (1~5% doses of commercialized CAR-T). Conclusion: Preliminary findings suggest that Meta10-19 infusion exhibits promising breakthrough efficacy and safety profile, and active enrollment is ongoing to validate the initial results. Citation Format: Yugang Guo, Qianwen Xu, Lei Xue, Erling Chen, Chonglin Liu, Min Gao, Youjia Li, Jingjing Ren, Jinping Li, Li Tang, Xingbing Wang. Metabolically armed CD19 CAR-T cells for safe and effective treatment of relapsed or refractory CD19+ B cell hematological malignancies at extremely low doses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB236.

Chemoattractant receptor signaling in humoral immunity.

Efficient induction of humoral immune responses depends on the orchestrated migration of B cells within lymphoid organs, which is governed by G protein-coupled receptors (GPCRs) responding to chemoattractants, represented by chemokines. After ligand binding, GPCRs are phosphorylated by different GPCR kinases (GRKs) at distinct sites on the receptor C termini, which dictates functional outcomes of β-arrestin-mediated signaling, ranging from receptor inactivation to effector molecule activation. However, the molecular mechanisms by which individual GRKs are selectively targeted to GPCRs have been poorly understood. Our recent study revealed that a protein complex consisting of copper metabolism MURR1 domain-containing (COMMD) 3 and 8 (the COMMD3/8 complex) functions as an adaptor that recruits a specific GRK to chemoattractant receptors and plays an important role in the control of B-cell migration during humoral immune responses. In this review, we summarize the current understanding of chemoattractant receptor signaling in the context of humoral immunity and discuss the potential of the COMMD3/8 complex as a therapeutic target for autoimmune diseases.

IκBε deficiency accelerates disease development in chronic lymphocytic leukemia.

The NFKBIE gene, which encodes the NF-κB inhibitor IκBε, is mutated in 3-7% of patients with chronic lymphocytic leukemia (CLL). The most recurrent alteration is a 4-bp frameshift deletion associated with NF-κB activation in leukemic B cells and poor clinical outcome. To study the functional consequences of NFKBIE gene inactivation, both in vitro and in vivo, we engineered CLL B cells and CLL-prone mice to stably down-regulate NFKBIE expression and investigated its role in controlling NF-κB activity and disease expansion. We found that IκBε loss leads to NF-κB pathway activation and promotes both migration and proliferation of CLL cells in a dose-dependent manner. Importantly, NFKBIE inactivation was sufficient to induce a more rapid expansion of the CLL clone in lymphoid organs and contributed to the development of an aggressive disease with a shortened survival in both xenografts and genetically modified mice. IκBε deficiency was associated with an alteration of the MAPK pathway, also confirmed by RNA-sequencing in NFKBIE-mutated patient samples, and resistance to the BTK inhibitor ibrutinib. In summary, our work underscores the multimodal relevance of the NF-κB pathway in CLL and paves the way to translate these findings into novel therapeutic options.

Biodistribution and Safety of Human Multi-Chimeric Cells After Systemic Intraosseous and Intravenous Administration in the Experimental Mouse Model.

Cellular therapies provide promising options for inducing tolerance in transplantation of solid organs, bone marrow, and vascularized composite allografts. However, novel tolerance-inducing protocols remain limited, despite extensive research. We previously introduced and characterized a human multi-chimeric cell (HMCC) line, created through ex vivo fusion of human umbilical cord blood (UCB) cells derived from three unrelated donors. In this study, we assessed in vivo biodistribution and safety of HMCCs in the NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ NOD scid gamma (NSG) mouse model. Twenty-four NSG mice were randomly assigned to four groups (n = 6/group) and received intraosseous (IO.) or intravenous (IV.) injections of 0.6 × 106 donor UCB cells or fused HMCC: Group 1-UCB (IO.), Group 2-UCB (IV.), Group 3-HMCC (IO.), and Group 4-HMCC (IV.). Hematopoietic phenotype maintenance and presence of human leukocyte antigens (HLA), class I antigens, in the selected lymphoid and nonlymphoid organs were assessed by flow cytometry. Weekly evaluation and magnetic resonance imaging (MRI) assessed HMCC safety. Comparative analysis of delivery routes revealed significant differences in HLA class I percentages for IO.: 1.83% ± 0.79%, versus IV. delivery: 0.04% ± 0.01%, P < 0.01, and hematopoietic stem cell marker percentages of CD3 (IO.: 1.41% ± 0.04%, vs. IV.: 0.07% ± 0.01%, P < 0.05) and CD4 (IO.: 2.74% ± 0.31%, vs. IV.: 0.59% ± 0.11%, P < 0.01). Biodistribution analysis after IO. delivery confirmed HMCC presence in lymphoid organs and negligible presence in nonlymphoid organs, except for lung (IO.: 0.19% ± 0.06%, vs. IV.: 6.33% ± 0.56%, P < 0.0001). No evidence of tumorigenesis was observed by MRI at 90 days following IO. and IV. administration of HMCC. This study confirmed biodistribution and safety of HMCC therapy in the NSG mouse model, both following IO. and IV. administration. However, IO. delivery route confirmed higher efficacy of engraftment and safety profile, introducing HMCCs as a novel cell-based therapeutic approach with promising clinical applications in solid organ, bone marrow, and vascularized composite allotransplantation transplantation.

State of pneumococcal vaccine immunity.

Like the other invasive encapsulated bacteria, Streptococcus pneumoniae is also covered with a polysaccharide structure. Infants and elderly are most vulnerable to the invasive and noninvasive diseases caused by S. pneumoniae. Although antibodies against polysaccharide capsule are efficient in eliminating S. pneumoniae, the T cell independent nature of the immune response against polysaccharide vaccines renders them weakly antigenic. The introduction of protein conjugated capsular polysaccharide vaccines helped overcome the weak immunogenicity of pneumococcal polysaccharides and decreased the incidence of pneumococcal diseases, especially in pediatric population. Conjugate vaccines elicit T cell dependent response which involve the interaction of specialized CD4+ T cells, called follicular helper T cells (Tfh) with germinal center B cells in secondary lymphoid organs. Despite their improved immunogenicity, conjugate vaccines still need to be administered three to four times in infants during the first 15 month of their life because they mount poor Tfh response. Recent studies revealed fundamental differences in the generation of Tfh cells between neonates and adults. As the portfolio of pneumococcal conjugate vaccines continues to increase, better understanding of the mechanisms of antibody development in different age groups will help in the development of pneumococcal vaccines tailored for different ages.

Autoimmunity in thymic epithelial tumors: a not yet clarified pathologic paradigm associated with several unmet clinical needs.

Thymic epithelial tumors (TETs) are rare mediastinal cancers originating from the thymus, classified in two main histotypes: thymoma and thymic carcinoma (TC). TETs affect a primary lymphoid organ playing a critical role in keeping T-cell homeostasis and ensuring an adequate immunological tolerance against "self". In particular, thymomas and not TC are frequently associated with autoimmune diseases (ADs), with Myasthenia Gravis being the most common AD present in 30% of patients with thymoma. This comorbidity, in addition to negatively affecting the quality and duration of patients' life, reduces the spectrum of the available therapeutic options. Indeed, the presence of autoimmunity represents an exclusion criteria for the administration of the newest immunotherapeutic treatments with checkpoint inhibitors. The pathophysiological correlation between TETs and autoimmunity remains a mystery. Several studies have demonstrated the presence of a residual and active thymopoiesis in adult patients affected by thymomas, especially in mixed and lymphocytic-rich thymomas, currently known as type AB and B thymomas. The aim of this review is to provide the state of art in regard to the histological features of the different TET histotype, to the role of the different immune cells infiltrating tumor microenvironments and their impact in the break of central immunologic thymic tolerance in thymomas. We discuss here both cellular and molecular immunologic mechanisms inducing the onset of autoimmunity in TETs, limiting the portfolio of therapeutic strategies against TETs and greatly impacting the prognosis of associated autoimmune diseases.

Advances in the study of tertiary lymphoid structures in the immunotherapy of breast cancer.

Breast cancer, as one of the most common malignancies in women, exhibits complex and heterogeneous pathological characteristics across different subtypes. Triple-negative breast cancer (TNBC) and HER2-positive breast cancer are two common and highly invasive subtypes within breast cancer. The stability of the breast microbiota is closely intertwined with the immune environment, and immunotherapy is a common approach for treating breast cancer.Tertiary lymphoid structures (TLSs), recently discovered immune cell aggregates surrounding breast cancer, resemble secondary lymphoid organs (SLOs) and are associated with the prognosis and survival of some breast cancer patients, offering new avenues for immunotherapy. Machine learning, as a form of artificial intelligence, has increasingly been used for detecting biomarkers and constructing tumor prognosis models. This article systematically reviews the latest research progress on TLSs in breast cancer and the application of machine learning in the detection of TLSs and the study of breast cancer prognosis. The insights provided contribute valuable perspectives for further exploring the biological differences among different subtypes of breast cancer and formulating personalized treatment strategies.

Presence of immunoglobulin E-expressing antibody-secreting cells in the dermis close to bullous pemphigoid lesions.

Antibody-secreting cells (ASCs) produce immunoglobulin (Ig) G and IgE autoantibodies in secondary lymphoid organs. Evidence also suggests their existence in the skin in various chronic inflammatory conditions, and in association with CXCL12 and CXCL13, they regulate the recruitment/survival of ASCs and germinal center formation to generate ASCs, respectively. However, the presence of IgG and IgE in bullous pemphigoid (BP) lesions needs to be addressed. Here, we aimed to analyse BP skin for the presence of IgG and IgE and the factors contributing to their generation, recruitment, and persistence. Skin samples from 30 patients with BP were stained to identify ASCs and the immunoglobulin type they expressed. The presence of tertiary lymphoid organ (TLO) elements, which generate ASCs in non-lymphoid tissues, and the chemokines CXCL12 and CXCL13, which regulate the migration/persistence of ASCs in lymphoid tissues and formation of TLOs, respectively, were evaluated in BP skin. BP skin harboured ASCs expressing the two types of antibodies IgG and IgE. ASCs were found in high-grade cellular aggregates containing TLO elements: T cells, B cells, CXCL12+ cells, CXCL13+ cells and high endothelial venules. IgG+ ASCs were detected among these aggregates, whereas IgE+ ASCs were dispersed throughout the dermis. CXCL12+ fibroblast-like cells were located close to ASCs. The inflammatory microenvironment of BP lesions may contribute to the antibody load characteristic of the skin of patients with BP by providing a site for the presence of ASCs. CXCL13 and CXCL12 expression may contribute to the generation and recruitment/survival of ASCs, respectively.

The atypical IκB family member Bcl3 determines differentiation and fate of intestinal RORγt+ regulatory T-cell subsets

Peripherally induced regulatory T cells (pTregs) expressing the retinoic acid receptor-related orphan-receptor gamma t (RORγt) are indispensable for intestinal immune homeostasis. NF-κB family members regulate the differentiation of thymic Tregs and promote their survival in the periphery. However, the Treg-intrinsic molecular mechanisms controling the size of the pTregs in the intestine and associated lymphoid organs remain unclear. Here, we provide direct evidence that Bcl3 limits the development of pTregs in a T cell-intrinsic manner. Moreover, the absence of Bcl3 allowed for the formation of an unusual intestinal Treg population co-expressing the transcription factors Helios and RORγt. The expanded RORγt+ Treg populations in the absence of Bcl3 displayed an activated phenotype and secreted high levels of the anti-inflammatory cytokines IL-10 and TGFβ. They were fully capable of suppressing effector T cells in a transfer colitis model despite an intrinsic bias to trans-differentiate toward Th17-like cells. Finally, we provide a Bcl3-dependent gene signature in pTregs including altered responsiveness to the cytokines IL-2, IL-6, and TNFα. Our results demonstrate that Bcl3 acts as a molecular switch to limit the expansion of different intestinal Treg subsets and may thus serve as a novel therapeutic target for inflammatory bowel disease by restoring intestinal immune tolerance.

Possible role of endoplasmic reticulum stress in the pathogenesis of chronic adenoiditis and adenoid hypertrophy: A prospective, parallel-group study.

Adenoid tissue is a first-line host defense secondary lymphoid organ, especially in childhood. The endoplasmic reticulum (ER) is required to maintain balanced cellular activity. With impaired ER functions, protein accumulation occurs, resulting in ER stress, which plays a role in the etiopathogenesis of many diseases. We aimed to investigate the relationship between ER stress and adenoid tissue disorders, thereby elucidating the mechanisms of immunity-related diseases. Fifty-four pediatric patients (>3 years old) who underwent adenoidectomy for chronic adenoiditis (CA) or adenoid hypertrophy (AH) were enrolled in this prospective, parallel-group clinical study. Adenoids were divided into two groups (CA or AH) based on their size and evaluated for ER stress pathway and apoptosis pathway markers by Real-time PCR and Western blot analysis. ER stress pathway markers significantly differed between the CA and AH groups. Children with CA had higher ER stress marker levels than the AH group (p < .001 for ATF-4, ATF-6, and GRP78, and p < .05 for EDEM1, CHOP, EIF2AK3, ERNI, and GRP94). Apoptosis pathway marker levels (BAX and BCL-2) were not different between groups. ER stress contributes to the etiopathogenesis of adenoid tissue diseases and the pathogenesis of adenoid tissue disorders, which are part of the immune response. These results may guide the development of new and alternative treatments for immune system disorders.

T cell help induces Myc transcriptional bursts in germinal center B cells during positive selection.

Antibody affinity maturation occurs in secondary lymphoid organs within germinal centers (GCs). At these sites, B cells mutate their antibody-encoding genes in the dark zone, followed by preferential selection of the high-affinity variants in the light zone by T cells. The strength of the T cell-derived selection signals is proportional to the B cell receptor affinity and to the magnitude of subsequent Myc expression. However, because the lifetime of Myc mRNA and its corresponding protein is very short, it remains unclear how T cells induce sustained Myc levels in positively selected B cells. Here, by direct visualization of mRNA and active transcription sites in situ, we found that an increase in transcriptional bursts promotes Myc expression during B cell positive selection in GCs. Elevated T cell help signals predominantly enhance the percentage of cells expressing Myc in GCs as opposed to augmenting the quantity of Myc transcripts per individual cell. Visualization of transcription start sites in situ revealed that T cell help promotes an increase in the frequency of transcriptional bursts at the Myc locus in GC B cells located primarily in the LZ apical rim. Thus, the rise in Myc, which governs positive selection of B cells in GCs, reflects an integration of transcriptional activity over time rather than an accumulation of transcripts at a specific time point.

Type I interferon promotes the fate of Toll-like receptor 9-stimulated follicular B cells to plasma cell differentiation.

The activation and differentiation of B cells into plasma cells (PCs) play critical roles in the immune response to infections and autoimmune diseases. Toll-like receptor 9 (TLR9) responds to bacterial and viral DNA containing unmethylated CpG motifs and triggers immune responses in B cells; however, abnormal recognition of self-DNA by TLR9 can cause autoimmune diseases. When stimulated with TLR9 agonists, follicular (FO) B cells, a subset of B cells residing in the FO regions of secondary lymphoid organs, exhibit a propensity for activation but fail to give rise to PCs. The factors that enable the transition of TLR9-activated FO B cells from activation to differentiation into PCs remain unclear. In this study, we show that type I interferon-alpha (IFNα) signaling causes FO B cells activated by CpG stimulation to differentiate into PCs. Although CpG stimulation alone only temporarily increased interferon regulatory factor 4 (IRF4) expression in FO B cells, co-stimulation with both CpG and IFNα enhanced and maintained high IRF4 expression levels, ultimately enabling the cells to differentiate into PCs. Overexpression of IRF4 in FO B cells results in CpG-induced PC transition without IFN signaling. Furthermore, co-stimulation of TLR9 and IFNα receptors significantly enhanced mammalian target of rapamycin (mTOR) signaling, which regulates IRF4 expression and PC generation. These findings suggest that IFNα may play a key role in promoting the fate of PC differentiation in FO B cells activated by TLR9 stimulation.

Stochastic modeling of a gene regulatory network driving B cell development in germinal centers.

Germinal centers (GCs) are the key histological structures of the adaptive immune system, responsible for the development and selection of B cells producing high-affinity antibodies against antigens. Due to their level of complexity, unexpected malfunctioning may lead to a range of pathologies, including various malignant formations. One promising way to improve the understanding of malignant transformation is to study the underlying gene regulatory networks (GRNs) associated with cell development and differentiation. Evaluation and inference of the GRN structure from gene expression data is a challenging task in systems biology: recent achievements in single-cell (SC) transcriptomics allow the generation of SC gene expression data, which can be used to sharpen the knowledge on GRN structure. In order to understand whether a particular network of three key gene regulators (BCL6, IRF4, BLIMP1), influenced by two external stimuli signals (surface receptors BCR and CD40), is able to describe GC B cell differentiation, we used a stochastic model to fit SC transcriptomic data from a human lymphoid organ dataset. The model is defined mathematically as a piecewise-deterministic Markov process. We showed that after parameter tuning, the model qualitatively recapitulates mRNA distributions corresponding to GC and plasmablast stages of B cell differentiation. Thus, the model can assist in validating the GRN structure and, in the future, could lead to better understanding of the different types of dysfunction of the regulatory mechanisms.

Regulatory T cells expressing CD19-targeted chimeric antigen receptor restore homeostasis in Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is a progressive disease leading to immune-mediated tissue damage, associated with an alteration of lymphoid organs. Therapeutic strategies involving regulatory T (Treg) lymphocytes, which physiologically quench autoimmunity and support long-term immune tolerance, are considered, as conventional treatment often fails. We describe here a therapeutic strategy based on Tregs overexpressing FoxP3 and harboring anti-CD19 CAR (Fox19CAR-Tregs). Fox19CAR-Tregs efficiently suppress proliferation and activity of B cells in vitro, which are relevant for SLE pathogenesis. In an humanized mouse model of SLE, a single infusion of Fox19CAR-Tregs restricts autoantibody generation, delay lymphopenia (a key feature of SLE) and restore the human immune system composition in lymphoid organs, without detectable toxicity. Although a short survival, SLE target organs appear to be protected. In summary, Fox19CAR-Tregs can break the vicious cycle leading to autoimmunity and persistent tissue damage, representing an efficacious and safe strategy allowing restoration of homeostasis in SLE.

Cross-sectional imaging in symmetrical bilateral extranodal recurrence of follicular lymphoma: A case report

Follicular lymphoma (FL) constitutes nearly 30% of all lymphomas, making it the second most prevalent B-cell lymphoma. It exhibits an indolent course within the spectrum of non-Hodgkin lymphoma, with variable 5-year progression-free survival rates. Histologically graded 1&amp;ndash;3, FL primarily affects bone marrow and lymphoid organs but may also involve extranodal tissues, such as bilateral muscle tissue. This report outlines the diagnostic challenges associated with disease recurrence in such unusual locations, emphasizing the need for vigilance among clinicians and radiologists. Through imaging and biopsy, we confirmed recurrence in the patient. The study highlights the role of 18F-FDG PET/CT in detecting uncommon FL sites and guiding treatment decisions while emphasizing the importance of multidisciplinary care for optimal patient management.