CD5 and B lymphocyte responses: multifaceted effects through multitudes of pathways and channels

PGRN Inhibits Early B-cell Activation and IgE Production Through the IFITM3-STAT1 Signaling Pathway in Asthma

Progranulin (PGRN) plays a critical role in bronchial asthma and the function of various immune cells. However, the mechanisms by which PGRN influences B-cell receptor (BCR) signaling and immunoglobulin E(IgE) production are not fully understood. The study aimed to elucidate the molecular mechanisms through which PGRN affects BCR signaling, B-cell differentiation, and IgE production. A PGRN knockout mouse model, along with techniques including flow cytometry, the creation of a bone marrow chimeric mouse model, total internal reflection fluorescence (TIRF), and Western blot (WB) analysis is employed, to investigate the link between PGRN and various aspects of B-cell biology. It is discovered that the absence of PGRN in mice alters peripheral B-cell subpopulations, promotes IgE class switching in a cell-intrinsic manner, and affects B-cell subpopulations. Additionally, PGRN modulates B-cell functions by regulating BCR signaling pathways, metabolic processes, and the actin cytoskeleton during early B-cell activation. Significantly, PGRN deficiency results in diminished production of NP-specific antibodies. Moreover, it is found that PGRN inhibits B-cell activation and IgE production through the PGRN-IFITM3-STAT1 signaling pathway. The findings provide new strategies for the targeted treatment of bronchial asthma, highlighting the crucial role of PGRN in B-cell signaling and IgE production.

Tumor Biology Hides Novel Therapeutic Approaches to Diffuse Large B-Cell Lymphoma: A Narrative Review

Diffuse large B-cell lymphoma (DLBCL) is a malignancy of immense biological and clinical heterogeneity. Based on the transcriptomic or genomic approach, several different classification schemes have evolved over the years to subdivide DLBCL into clinically (prognostically) relevant subsets, but each leaves unclassified samples. Herein, we outline the DLBCL tumor biology behind the actual and potential drug targets and address the challenges and drawbacks coupled with their (potential) use. Therapeutic modalities are discussed, including small-molecule inhibitors, naked antibodies, antibody-drug conjugates, chimeric antigen receptors, bispecific antibodies and T-cell engagers, and immune checkpoint inhibitors. Candidate drugs explored in ongoing clinical trials are coupled with diverse toxicity issues and refractoriness to drugs. According to the literature on DLBCL, the promise for new therapeutic targets lies in epigenetic alterations, B-cell receptor and NF-κB pathways. Herein, we present putative targets hiding in lipid pathways, ferroptosis, and the gut microbiome that could be used in addition to immuno-chemotherapy to improve the general health status of DLBCL patients, thus increasing the chance of being cured. It may be time to devote more effort to exploring DLBCL metabolism to discover novel druggable targets. We also performed a bibliometric and knowledge-map analysis of the literature on DLBCL published from 2014-2023.

Prevalence and Prognostication of CD5+ Mature T-Cell Lymphomas

Background: T-cell lymphomas (TCLs) are a group of heterogenous cancers with poor rates and duration of response. There remains a great challenge in risk stratification of these cancers. Cluster of differentiation (CD) 5 has shown prognostic implication in many subtypes of B-cell lymphoma; however, its role in TCLs is not known. Methods: We performed a single-institution retrospective analysis of newly diagnosed patients with TCL. CD5 positivity was determined based on positive results via immunohistochemistry and/or flow cytometry. We used univariate and multivariable analysis of biological factors to assess their association with survival outcomes. Results: A total of 194 patients with TCL spanning 14 subtypes were identified. CD5 positivity was noted in 63% of patients, with the highest proportion of CD5 expression in TFH TCL (93.9%), PTCL-NOS (82.9%), and ATLL (77.8%) (p = 0.00004). Older age at diagnosis (p = 0.001), stage III or IV disease (p = 0.05), and bone marrow involvement (p = 0.003) were also associated with CD5 expression. Complete response rates were numerically lower in patients with CD5+ TCL across all subtypes. OS/PFS was not statistically associated with CD5 status in the overall cohort; however there was significantly decreased OS in CD5+ TFH TCL (p = 0.04) and CD5+ ATLL (p = 0.04) patients. Conclusions: This study represents the first to examine CD5 expression as a prognostic biomarker for outcomes in TCL. The frequent expression of CD5 in the most common nodal TCL in the Western world underpins its potential as an attractive target for cellular therapies. Confirmation of these findings in a larger cohort and investigation of potential pathophysiological mechanisms explaining our observations are planned.

Identification and validation of hub genes in CD5-positive diffuse large B-cell lymphoma

CD5+ diffuse large B-cell lymphoma (DLBCL), as a significant heterogeneity category of DLBCL, is reflected in both the molecular biological and genetic levels, which in turn induces ever-changing clinical manifestations, and what mediates tumor survival mechanisms are still unclear. This study aimed to predict the potential hub genes in CD5+ DLBCL. A total of 622 patients with DLBCL diagnosed between 2005 and 2019 were included. High expression of CD5 was correlated with IPI, LDH, and Ann Arbor stage, patients with CD5-DLBCL have longer overall survival. We identified 976 DEGs between CD5-negative and positive DLBCL patients in the GEO database and performed GO and KEGG enrichment analysis. After intersecting the genes obtained through the Cytohubba and MCODE, further external verification was performed in the TCGA database. Three hub genes were screened: VSTM2B, GRIA3, and CCND2, of which CCND2 were mainly involved in cell cycle regulation and JAK-STAT signaling pathways. Analysis of clinical samples showed that the expression of CCND2 was found to be correlated with CD5 (p = 0.001), and patients with overexpression of CCND2 in CD5+ DLBCL had poor prognosis (p = 0.0455). Cox risk regression analysis showed that, for DLBCL, CD5, and CCND2 double positive was an independent poor prognostic factor (HR: 2.545; 95% CI: 1.072-6.043; p = 0.034). These findings demonstrate that CD5 and CCND2 double-positive tumors should be stratified into specific subgroups of DLBCL with poor prognosis. CD5 may regulate CCND2 through JAK-STAT signaling pathways, mediating tumor survival. This study provides independent adverse prognostic factors for risk assessment and treatment strategies for newly diagnosed DLBCL.

Shifting gears: Study of immune system parameters of male habitual marathon runners

Aim

Marathon is a running event in which athletes must cover a distance of 42.195 km. In addition to participating in marathons, marathoners have incorporated extensive running into their lifestyle. In the present study, we investigated the effect of long-term strenuous exercise in the form of marathon running on the immune system.

Methods & Results

We collected peripheral blood samples from 37 male marathoners before/after a race and 37 age/sex/body mass index (BMI)-matched healthy sedentary controls. Hematological and biochemical tests revealed race-induced leukocytosis attributable to neutrophilia and significant increases in plasma lactate dehydrogenase (LDH), creatine phosphokinase (CPK), and cortisol concentrations. Phenotypic analysis of lymphocytes revealed race-induced significant decrease in the number of lymphocytes, memory helper T (Th) cells, naive, memory and activated cytotoxic T (Tc) cells, natural killer (NK), NKT, and B1 cells, and a significant increase in the number of activated Th and regulatory Th cells (Tregs). Compared with controls, marathoners maintained significantly lower levels of memory and activated Th cells and higher levels of activated Tc and B1 cells. Measurement of plasma cytokine levels revealed a pro-inflammatory cytokine polarization that increased after the race. Examination of gene expression of cytokines and Th-cell signature transcription factors in peripheral blood mononuclear cells revealed a significant decrease in tumor necrosis factor α (TNF-α) and interleukin (IL)-17, and a significant increase in IL-6, IL-10 and forkhead box P3 (FoxP3) after the race. Compared with controls, marathoners maintained significantly higher levels of TNF-α. Assessment of the suppressive capacity of Tregs in co-cultures of isolated effector Th cells and Tregs showed significantly increased suppressive capacity of marathoners' Tregs after the race.

Conclusions

Compared with controls, marathoners live with permanent changes in certain immune parameters. Marathoners exhibit a stable pro-inflammatory cytokine polarization that increases after the race and is counterbalanced by increased numbers of Tregs overexpressing FoxP3 and having increased suppressive capacity.

B cell phenotypes and maturation states in cows naturally infected with Mycobacterium avium subsp. Paratuberculosis

Little is known about the role that B cells play in immune responses to infection with the intracellular pathogen, Mycobacterium avium subsp. paratuberculosis (MAP). Traditionally, the role of B cells has been constrained to their function as antibody-producing cells, however, antibodies are not thought to play a protective role in mycobacterial infections. The present study was designed to characterize B cell subpopulations as well as activation/maturation states in cattle with paratuberculosis. Peripheral blood mononuclear cells (PBMCs) were isolated from noninfected control cows (n = 8); as well cattle naturally infected with MAP in the subclinical (n = 8) and clinical (n = 7) stage of infection and stimulated with MAP antigen for 6 days. MAP infection resulted in greater numbers of total B cells for clinical cows compared to control noninfected cows. The major subpopulation in freshly isolated PBMCs in clinical cows was B-1a B cells, but this shifted to a composite of both B-1a and B-2 B cells upon stimulation of PBMCs with either MAP antigen or pokeweed mitogen, with higher numbers of B-2 B cells. Early B cells were observed to predominate the population of B cells in PBMCs, with lesser populations of germinal B cells, memory B cells and plasma cells. These subpopulations were elevated in clinical cows upon stimulation of PBMCs with MAP antigen, except for plasma cells which were lower compared to control noninfected cows. Increased numbers of B cells in clinical cows aligned with higher expression of B cell markers such as MAPK1/3, BTG1, Bcl2, CD79A and SWAP70, depending upon in vitro stimulation with either mitogen or antigen. This would indicate that the B cells were capable of activation but were anti-apoptotic in nature. The shift to B-2 B cells in the periphery of clinical cows seems to be indicative of an expansion of memory B cells, rather than plasma cells. This may be a last attempt by the host to control the rampant inflammatory state associated with advanced clinical disease.

Population-based study on the association between autoimmune disease and lymphoma: National Health Insurance Service-National Sample Cohort 2002-2015 in Korea

BACKGROUND

We aimed to evaluate the association between autoimmune disease (AID) and lymphoma incidence in the Korean population. We also aimed to compare the overall survival (OS) in patients with AID-associated lymphoma (AAL) with that in patients with lymphoma without AID.

MATERIAL AND METHODS

We used National Sample Cohort 2002-2015 provided by National Health Insurance Service. Among 1,011,638 patients, 994,496 were recruited for the final cohort: 130,987 patients (13.2%) in the AID group and 863,509 (86.8%) in control. Lymphoma was diagnosed in 1162 patients and 322 patients with accompanying AID, irrespective of the time point of diagnosis, were defined as AAL. Of those, patients who experienced lymphoma development at least one year after AID diagnosis were defined as post-AID lymphoma (N = 155).

RESULTS

The median follow-up duration was 13.7 years. AAL accounted for 0.03% of total and 27.7% of lymphoma cases. AID patients experienced more Epstein-Barr virus (0.02 vs. 0.01%, P = 0.027) or Helicobacter pylori infection (63.9 vs. 41.4%, P < 0.001) than the control group did. AID was associated with a 1.45-fold increased risk of lymphoma. The median time interval from AID to AAL was 10.9 months. The risk of lymphoma increased in the order of: psoriasis (adjusted odds ratio [AOR] 1.61), systemic lupus erythematosus (AOR 3.99), multiple sclerosis (AOR 4.52), and sarcoidosis (AOR 26.37). Sjogren syndrome was not related to lymphoma in this cohort. The 5-year OS in AAL was not different from that in lymphoma patients without AID (60.9 vs. 61.5%, P = 0.970).

CONCLUSIONS

The association patterns in AAL in Korean population were different from those of Western countries. Further studies on lymphomatogenesis from distinct baseline characteristics (e.g. chronic infection status) would elucidate the difference based on race and ethnicity.