Chronic lymphocytic leukemia (CLL) is most frequently diagnosed at early, asymptomatic stages (Rai 0/Binet A), in which a watch-and-wait strategy remains the standard of care, based on historical trials demonstrating no overall survival benefit from early treatment. Over the past two decades, however, substantial advances in genomic profiling-including immunoglobulin heavy-chain variable region (IGHV) mutational status, TP53 disruption, recurrent gene mutations, and complex karyotype-have uncovered marked biological heterogeneity among early-stage patients and substantially improved prediction of disease progression. In parallel, targeted therapies such as Bruton tyrosine kinase (BTK) inhibitors and venetoclax-based combinations have transformed the management of symptomatic CLL, raising renewed interest in whether early intervention might favorably alter the natural history of biologically high-risk disease. In this review, we critically examine the evolution of prognostication in early-stage CLL, integrate contemporary molecular and clinical risk models, and summarize evidence from both historical chemotherapy-era studies and modern early-intervention trials. We discuss key unresolved controversies, including reliance on surrogate endpoints, the risks of overtreatment, and the persistent absence of an overall survival benefit across all early-treatment strategies. Finally, we outline future research priorities, including refined genomic stratification, minimal residual disease-driven (MRD)-driven approaches, and combination targeted therapies currently under investigation. Despite renewed interest in preemptive treatment, available evidence supports continued observation for asymptomatic patients outside clinical trials.

Chronic lymphocytic leukemia (CLL) is a dynamic malignancy in which intraclonal subfractions differ in activation history and responsiveness to microenvironmental signals. Here, we investigated the expression and inducibility of IL-12 family receptor subunits (IL-23R, IL-12Rβ1, IL-12Rβ2) and the related receptor complexes in recirculating CLL cells, with a focus on CXCR4/CD5-defined fractions: the proliferative fraction (PF; CXCR4dim/CD5bright; most recently divided, tissue-emigrated cells) and the resting fraction (RF; CXCR4bright/CD5dim; older, quiescent cells). At baseline, IL-12Rβ1 was enriched in the PF and was associated with a higher proportion of cells expressing IL-23R and IL-12R receptor complexes. Concomitantly, RT-qPCR disclosed higher IL-12Rβ1 mRNA levels. Following antigen-independent activation with CpG or CpG + IL-15, there was a marked increase in IL-23R and IL-12Rβ1 but not in IL-12Rβ2 surface expression, resulting in preferential upregulation of the IL-23R complex over the IL-12R complex. Fraction-specific analyses showed stronger induction of IL-23R and IL-23R complex expression in PF compared with RF. These findings identify an intraclonal bias toward IL-23 responsiveness in the CLL cells with a phenotype of recently divided, tissue-emigrated cells and suggest the IL-23/IL-23R axis as a potential therapeutic target.

Background/Objectives: The immunoglobulin heavy-chain variable (IGHV) gene repertoire represents a characteristic feature of chronic lymphocytic leukemia (CLL), although its configuration is not well defined at the early disease stages. The IGHV repertoire of a cohort of early CLL patients was analyzed and compared to that of a "real-world" reference cohort. Methods: Patients from the O-CLL1 observational protocol, which enrolled only Binet stage A cases within twelve months from diagnosis, were studied. IGHV/IGHJ rearrangements were sequenced and annotated following ERIC recommendations, and stereotyped subsets were assigned using ARResT/AssignSubsets. The repertoire features were compared with the dataset of a real-world cohort of patients with heterogeneous staging (CTR cohort) and with published early-diagnosis series. Results: IGHV and IGHJ gene distributions and HCDR3-length profiles in O-CLL1 closely mirrored those of CTR, indicating that the BcR IG repertoire at diagnosis is already defined rather than being selected during disease progression. Mutated IGHV (M-CLL) predominated, with a frequency of stereotyped BcR IG comparable to that of other early-diagnosis cohorts. However, within this conserved framework, subset #4 was over-represented among M-CLL from O-CLL without an increased overall IGHV4-34 gene usage, suggestive of a selective expansion rather than a recombinational bias. Subset #4 cases retained canonical HCDR3 motifs and showed time-to-first-treatment like other M-CLL, likely reflecting the younger age structure of O-CLL1. Conclusions: Early-diagnosis CLL displays a biased IGHV repertoire with stereotyped configurations characteristic of CLL, including subsets that are rare in the normal B-cell repertoire. These findings support a central role for antigen-driven selection in shaping CLL evolution.

In Chronic Lymphocytic Leukemia (CLL), mutations at the TP53 tumor suppressor gene are an important hallmark since they may strongly influence the therapeutic decision. PRIMA-1Met (also known as APR-246/Eprenetapopt) is a small molecule able to restore the wild-type (wt) p53 conformation to mutant p53 proteins and to stimulate apoptosis in tumor cells; in addition, it can deplete the glutathione reservoir, increasing reactive oxygen species (ROS) production. In this study, we investigated whether combining PRIMA-1Met with Sulfasalazine (SAS), a SLC7A11/xCT inhibitor, reduces CLL cell viability by targeting mutant p53 and the glutathione pathway. The results demonstrated that, in CLL cells, PRIMA-1Met did not restore the wt functions in the mutant p53 proteins, but it strongly reduced the antioxidant defense and induced cell death. PRIMA-1Met and SAS combination synergistically reduced cell survival regardless of p53 status and further impaired antioxidant capacity, especially in mutant p53 cells, linking their cytotoxic effect to redox imbalance. Thus, the association of PRIMA-1Met with drugs targeting the antioxidant response could represent a valid strategy to kill CLL cells carrying either wt or mutant p53.

Chronic lymphocytic leukemia (CLL) is sustained by complex interactions with the microenvironment, which provides signals for leukemic cell survival and proliferation. Among these, cytokines of the IL-12 family have emerged as relevant regulators of immune responses and tumor biology, yet their contribution to CLL remains incompletely defined. Previous studies showed that CLL cells can acquire responsiveness to IL-23 after T cell–dependent stimulation with CD40L, raising the question of whether T cell–independent signals can similarly induce functional receptor expression. Here we investigated the effect of CpG oligodeoxynucleotides, alone or in combination with interleukin-15 (IL-15), on IL-12 family receptor expression in CLL cells. We found that CpG + IL-15 stimulation significantly increased IL-23R and IL-12Rβ1 expression, while IL-12Rβ2 remained largely unresponsive. As a consequence, the complete IL-23 receptor complex was robustly induced, whereas IL-12 receptor assembly was only marginally enhanced. This skewing toward IL-23 rather than IL-12 signaling suggests that innate immune stimuli preferentially promote pathways supporting inflammation and survival, while limiting tumor-suppressive IL-12 responsiveness. Analysis of intraclonal heterogeneity revealed an asymmetric distribution of IL-23R among CXCR4/CD5-defined subfractions: the proliferative fraction, representing recently divided cells, expressed higher levels of IL-23R compared to the resting fraction. These findings suggest that IL-23 responsiveness is particularly enriched in the proliferating compartment of the leukemic clone. Overall, our results indicate that CpG and IL-15 stimulation drive a selective expansion of IL-23 signaling capacity in CLL, with preferential engagement of proliferative subfractions. This imbalance between IL-23 activation and insufficient IL-12Rβ2 induction may represent a critical pathogenic mechanism and a potential therapeutic target. ### Competing Interest Statement The authors have declared no competing interest.

Although chronic lymphocytic leukemia (CLL) is diagnosed by identifying a circulating B-cell clone that exceeds 5x103/μL, additional distinct clones (ADC) have been identified in various studies. Notably, the numbers of ADC documented in these studies has increased as the various technologies evolved. To better define the frequency and the characteristics of ADC in CLL, we used a next-generation sequencing platform that affords high sequencing depth along with steps that limit overcounting to analyze IGHV-IGHD-IGHJ gene rearrangements in circulating CD5+ B cells from 57 patients. Notably, all patients had at least one ADC, in addition to the clinically relevant clone. In 46 patients for whom lymphocyte count data were available, 44 had at least one ADC above the threshold of 1 B cell/μL and, remarkably, the average number of ADC was 12 per patient. Notably, in two patients, the predominant ADC qualified clinically as a separate CLL clone and in the remaining cases as low/high-count monoclonal B-cell lymphocytosis clones. Moreover, in 11 patients studied longitudinally, predominant ADC were persistent and often increased in number. ADC in patients with CLL exhibited 4-fold more stereotyped IGHV-IGHD-IGH rearrangements than found in CD5+ B cells from healthy individuals, and IGHV use, somatic mutations, and Ig isotype distribution were similar between predominant ADC and clinically relevant clones. Thus, finding multiple expanded clones within the CD5+ B cells is the rule in patients with CLL, indicating that leukemogenesis is a multiclonal process that likely involves competition among B cells with special B-cell receptor features.

A “watch and wait” strategy, delaying treatment until active disease manifests, is adopted for most CLL cases; however, prognostic models incorporating biomarkers have shown to be useful to predict treatment requirement. In our prospective O-CLL1 study including 224 patients, we investigated the predictive role of 513 microRNAs (miRNAs) on time to first treatment (TTFT). In the context of this study, six well-established variables (i.e., Rai stage, beta-2-microglobulin levels, IGVH mutational status, del11q, del17p, and NOTCH1 mutations) maintained significant associations with TTFT in a basic multivariable model, collectively yielding a Harrell’s C-index of 75% and explaining 45.4% of the variance in the prediction of TTFT. Concerning miRNAs, 73 out of 513 were significantly associated with TTFT in a univariable model; of these, 16 retained an independent relationship with the outcome in a multivariable analysis. For 8 of these (i.e., miR-582-3p, miR-33a-3p, miR-516a-5p, miR-99a-5p, and miR-296-3p, miR-502-5p, miR-625-5p, and miR-29c-3p), a lower expression correlated with a shorter TTFT, whereas in the remaining eight (i.e., miR-150-5p, miR-148a-3p, miR-28-5p, miR-144-5p, miR-671-5p, miR-1-3p, miR-193a-3p, and miR-124-3p), the higher expression was associated with shorter TTFT. Integrating these miRNAs into the basic model significantly enhanced predictive accuracy, raising the Harrell’s C-index to 81.1% and the explained variation in TTFT to 63.3%. Moreover, the inclusion of the miRNA scores enhanced the integrated discrimination improvement (IDI) and the net reclassification index (NRI), underscoring the potential of miRNAs to refine CLL prognostic models and providing insights for clinical decision-making. In silico analyses on the differently expressed miRNAs revealed their potential regulatory functions of several pathways, including those involved in the therapeutic responses. To add a biological context to the clinical evidence, an miRNA–mRNA correlation analysis revealed at least one significant negative correlation between 15 of the identified miRNAs and a set of 50 artificial intelligence (AI)-selected genes, previously identified by us as relevant for TTFT prediction in the same cohort of CLL patients. In conclusion, the identification of specific miRNAs as predictors of TTFT holds promise for enhancing risk stratification in CLL to predict therapeutic needs. However, further validation studies and in-depth functional analyses are required to confirm the robustness of these observations and to facilitate their translation into meaningful clinical utility.

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, often presenting comorbidities like osteoporosis and requiring, in a relevant proportion of cases, treatment with bisphosphonates (BPs). This class of drugs was shown in preclinical investigations to also possess anticancer properties . We started an in vitro study of the effects of BPs on CLL B cells activated by microenvironment-mimicking stimuli and observed that, depending on drug concentration, hormetic effects were induced on the leukemic cells. Higher doses induced cytotoxicity whereas at lower concentrations, more likely occurring in vivo, the drugs generated a protective effect from spontaneous and chemotherapy-induced apoptosis, and augmented CLL B cell activation/proliferation. This CLL-activation effect promoted by the BPs was associated with markers of poor CLL prognosis and required the presence of bystander stromal cells. Functional experiments suggested that this phenomenon involves the release of soluble factors and is increased by cellular contact between stroma and CLL B cells. Since CLL patients often present comorbidities such as osteoporosis and considering the diverse outcomes in both CLL disease progression and CLL response to treatment among patients, illustrating this phenomenon holds potential significance in driving additional investigations.

Abstract Although chronic lymphocytic leukemia (CLL) is diagnosed by identifying in a patient’s blood a B-cell clone that exceeds 5x106/µL, additional clones have on occasion been identified. To characterize such clones in patients with CLL, we analyzed by NGS the IGHV-IGHD-IGHJ gene rearrangements in circulating CD5+ B cells from 57 untreated patients. In every patient, we identified additional distinct clonotypes (ADCs) from the clinically relevant clone (CRC). Even when defining clonal expansion using a rigorous threshold, 68% of patients had at least one expanded ADC. The predominant ADC (pADC) reached numbers qualifying as a CLL clone in two patients and qualifying as low/high-count monoclonal B-cell lymphocytosis in each other case. Over time, pADCs enlarged or shrank, suggesting an ongoing selection process. Stereotyped IGHV-D-J rearrangements were enriched in ADCs and IGHV usage and mutations revealed similarities specifically between pADCs and CRCs, while minor ADCs more closely resembled normal CD5+ B-cells. Thus, finding multiple expanded clones within the CD5+ B-cell population of patients with CLL is more the rule rather than the exception. Thus, leukemogenesis involves a competitive selection for dominance of more than one B-cell clone, with the process being influenced to some degree by the structure of the B-cell receptor.

Chronic Lymphocytic Leukemia (CLL) is caused by the clonal expansion of CD5+ B lymphocytes in the circulation, peripheral lymphoid organs and bone marrow [...]

EDITORIAL article Front. Oncol., 16 May 2023Sec. Hematologic Malignancies Volume 13 - 2023 | https://doi.org/10.3389/fonc.2023.1216398

PDF file 45K, List of data sets and case sconsidered for human GEP analysis

XLS file 1816K, Biological programs over-represented in the SPARC-related signature

COPYRIGHT © 2023 Agathangelidis, Ferrarini and Fais. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. TYPE Editorial PUBLISHED 23 March 2023 DOI 10.3389/fonc.2023.1188375

PDF file 62K, List of inflammatory up and down modulated genes in SPARC high human B-NHLs

Chronic lymphocytic leukemia (CLL) is the most frequent leukemia in Western countries. Although characterized by the progressive expansion and accumulation of leukemic B cells in peripheral blood, CLL cells develop in protective niches mainly located within lymph nodes and bone marrow. Multiple interactions between CLL and microenvironmental cells may favor the expansion of a B cell clone, further driving immune cells toward an immunosuppressive phenotype. Here, we summarize the current understanding of bone tissue alterations in CLL patients, further addressing and suggesting how the multiple interactions between CLL cells and osteoblasts/osteoclasts can be involved in these processes. Recent findings proposing the disruption of the endosteal niche by the expansion of a leukemic B cell clone appear to be a novel field of research to be deeply investigated and potentially relevant to provide new therapeutic approaches.

PDF file 1045K, Merged file (pdf) including methods, figures and legends

The engagement of the B cell receptor (BcR) on the surface of leukemic cells represents a key event in chronic lymphocytic leukemia (CLL) since it can lead to the maintenance and expansion of the neoplastic clone. This notion was initially suggested by observations of the CLL BcR repertoire and of correlations existing between certain BcR features and the clinical outcomes of single patients. Based on these observations, tyrosine kinase inhibitors (TKIs), which block BcR signaling, have been introduced in therapy with the aim of inhibiting CLL cell clonal expansion and of controlling the disease. Indeed, the impressive results obtained with these compounds provided further proof of the role of BcR in CLL. In this article, the key steps that led to the determination of the role of BcR are reviewed, including the features of the CLL cell repertoire and the fine mechanisms causing BcR engagement and cell signaling. Furthermore, we discuss the biological effects of the engagement, which can lead to cell survival/proliferation or apoptosis depending on certain intrinsic cell characteristics and on signals that the micro-environment can deliver to the leukemic cells. In addition, consideration is given to alternative mechanisms promoting cell proliferation in the absence of BcR signaling, which can explain in part the incomplete effectiveness of TKI therapies. The role of the BcR in determining clonal evolution and disease progression is also described. Finally, we discuss possible models to explain the selection of a special BcR set during leukemogenesis. The BcR may deliver activation signals to the cells, which lead to their uncontrolled growth, with the possible collaboration of other still-undefined events which are capable of deregulating the normal physiological response of B cells to BcR-delivered stimuli.

Abstract Chronic lymphocytic leukemia (CLL) cells express the interleukin-23 receptor (IL-23R) chain, but the expression of the complementary IL-12Rβ1 chain requires cell stimulation via surface CD40 molecules (and not via the B-cell receptor [BCR]). This stimulation induces the expression of a heterodimeric functional IL-23R complex and the secretion of IL-23, initiating an autocrine loop that drives leukemic cell expansion. Based on the observation in 224 untreated Binet stage A patients that the cases with the lowest miR-146b-5p concentrations had the shortest time to first treatment (TTFT), we hypothesized that miR-146b-5p could negatively regulate IL-12Rβ1 side chain expression and clonal expansion. Indeed, miR-146b-5p significantly bound to the 3′-UTR region of the IL-12Rβ1 mRNA in an in vitro luciferase assay. Downregulation of miR-146b-5p with specific miRNA inhibitors in vitro led to the upregulation of the IL-12Rβ1 side chain and expression of a functional IL-23R complex similar to that observed after stimulation of the CLL cell through the surface CD40 molecules. Expression of miR-146b-5p with miRNA mimics in vitro inhibited the expression of the IL-23R complex after stimulation with CD40L. Administration of a miR-146b-5p mimic to NSG mice, successfully engrafted with CLL cells, caused tumor shrinkage, with a reduction of leukemic nodules and of IL-12Rβ1–positive CLL cells in the spleen. Our findings indicate that IL-12Rβ1 expression, a crucial checkpoint for the functioning of the IL-23 and IL-23R complex loop, is under the control of miR-146b-5p, which may represent a potential target for therapy since it contributes to the CLL pathogenesis. This trial is registered at www.clinicaltrials.gov as NCT00917540.