Chronic lymphocytic leukemia (CLL) is characterized by disordered DNA methylation, suggesting these epigenetic changes might play a critical role in disease onset and progression. The ...methyltransferase
is a key regulator of DNA methylation. Although
somatic mutations in CLL are rare, we found that low
expression is associated with more aggressive disease. A conditional knockout mouse model showed that homozygous depletion of
from B cells results in the development of CLL with 100% penetrance at a median age of onset of 5.3 months, and heterozygous
depletion yields a disease penetrance of 89% with a median onset at 18.5 months, confirming its role as a haploinsufficient tumor suppressor. B1a cells were confirmed as the cell of origin of disease in this model, and
depletion resulted in focal hypomethylation and activation of
and
signaling. Amplification of chromosome 15 containing the
gene was detected in all CLL mice tested, and infiltration of high-
-expressing CLL cells in the spleen was observed. Notably, hyperactivation of
and
signaling was exclusively observed in the
CLL mice, but not in three other CLL mouse models tested (
,
, and
), and
-depleted CLL were sensitive to pharmacologic inhibition of
signaling
and
. Consistent with these findings, human CLL samples with lower
expression were more sensitive to
inhibition than those with higher
expression. Altogether, these results suggest that
depletion induces CLL that is highly dependent on activation of
and
signaling. SIGNIFICANCE: Loss of
expression is a driving event in CLL and is associated with aggressive disease, activation of
and
signaling, and enhanced sensitivity to
inhibition.
In immunosuppressed hosts, the development of multidrug resistance complicates the treatment of cytomegalovirus (CMV) infection. Improved genotypic detection of impending drug resistance may follow ...from recent technical advances. A severely T-cell-depleted patient with chronic lymphocytic leukemia developed CMV pneumonia and high plasma viral loads that were poorly responsive to antiviral therapy. Serial plasma specimens were analyzed for mutant viral populations by conventional and high-throughput deep-sequencing methods. Uncharacterized mutations were phenotyped for drug resistance using recombinant viruses. Conventional genotyping detected viruses with the UL97 kinase substitution C607Y after ganciclovir treatment, a transient subpopulation of UL54 polymerase L773V mutants first detected 8 weeks after foscarnet was started, and a subpopulation of a mutant with deletion of UL54 codons 981 and 982 2 months after the addition of cidofovir. Deep sequencing of the same serial specimens revealed the same UL54 mutants sooner, along with a more complex evolution of known and newly recognized mutant subpopulations missed by conventional sequencing. The UL54 exonuclease substitutions D413N, K513R, and C539G were newly shown to confer ganciclovir-cidofovir resistance, while L773V was shown to confer foscarnet resistance and add to the ganciclovir resistance conferred by UL97 C607Y. Increased sequencing depth provided a more timely and detailed diagnosis of mutant viral subpopulations that evolved with changing anti-CMV therapy.
In CLL, progressive disease (PD) following remission after first line treatment can present with varying phenotypes. We hypothesized that the mode of PD correlates with clinical outcomes. Data from ...three phase III trials of the German CLL Study Group (GCLLSG) (CLL8, CLL10, CLL11) including a total of 2159 patients receiving first line (immuno)-chemotherapy (FCR, FC, CLB, CLB-R, CLB-Ob) were analyzed. Patients were categorized as "ALC" if PD was due to increasing absolute lymphocyte count, or as "Ly" if due to lymphadenopathy. A group of 241 patients progressed with ALC, and 727 progressed with Ly, including 329 who progressed on both modalities. In fit patients, median TTNT after PD in the Ly group was 12.3 months vs 17.0 months in the ALC group (HR 1.299 1.036-1.628; P = .024). Median OS after PD was 45.1 months in the Ly group and 42.4 months in the ALC group (HR=1.023 0.753-1.389; P = .885). For unfit patients, median TTNT in the Ly group was 11.7 months vs 21.4 months in the ALC group (HR 1.357 1.051-1.753; P = .019). Median OS was 42.8 months in the Ly group and not reached in the ALC group (HR 1.851 1.280-2.677; P = .001). Patients in the Ly group more frequently showed impairment of quality of life (QoL). This analysis demonstrates that patients with progressive lymphadenopathy have a significantly shorter TTNT, OS and less favorable QoL. Our findings might help physicians to better estimate the clinical course of a progressing CLL patient.
An increased risk of developing atrial fibrillation (AF) has been observed in patients with chronic lymphocytic leukemia (CLL) who were treated with ibrutinib and other BTK inhibitors. Previous ...studies have explored the prevalence of AF in CLL and the risk of developing AF at time of diagnosis. However, the interaction between treatment type with other risk factors on risk of developing atrial fibrillation at the time of treatment initiation has not been investigated. This becomes particularly crucial in CLL, as there is often a substantial time gap between diagnosis and treatment, unlike many other cancers. We propose a treatment-aware approach using predictive modeling to identify the risk factors associated with AF at time of treatment initiation. Moreover, the model provides treatment-dependent risk factors by including the interaction between the treatment types and other risk factors. The results demonstrated that the treatment-aware modeling including interactions outperformed currentrisk scores.
The final analysis of the open-label, multicenter phase 2 CLL2-GIVe trial shows response and tolerability of the triple combination of obinutuzumab, ibrutinib, and venetoclax (GIVe regimen) in 41 ...previously untreated patients with high-risk chronic lymphocytic leukemia (CLL) with del(17p) and/or TP53 mutation. Induction consisted of 6 cycles of GIVe; venetoclax and ibrutinib were continued up to cycle 12 as consolidation. Ibrutinib was given until cycle 15 or up to cycle 36 in patients not achieving a complete response and with detectable minimal residual disease. The primary end point was the complete remission rate at cycle 15, which was achieved at 58.5% (95% CI, 42.1-73.7; P < .001). The last patient reached the end of the study in January 2022. After a median observation time of 38.4 months (range, 3.7-44.9), the 36-month progression-free survival was 79.9%, and the 36-month overall survival was 92.6%. Only 6 patients continued ibrutinib maintenance. Adverse events of concern were neutropenia (48.8%, grade ≥3) and infections (19.5%, grade ≥3). Cardiovascular toxicity grade 3 occurred as atrial fibrillation at a rate of 2.4% between cycles 1 and 12, as well as hypertension (4.9%) between cycles 1 and 6. The incidence of adverse events of any grade and grade ≥3 was highest during induction and decreased over time. Progressive disease was observed in 7 patients between cycles 27 and 42. In conclusion, the CLL2-GIVe regimen is a promising fixed-duration, first-line treatment for patients with high-risk CLL with a manageable safety profile.
In mice, generation of autoreactive CD5
B cells occurs as a consequence of BCR signaling induced by (self)-ligand exposure from fetal/neonatal B-1 B cell development. A fraction of these cells ...self-renew and persist as a minor B1 B cell subset throughout life. Here, we show that transfer of early generated B1 B cells from Eμ-TCL1 transgenic mice resulted in chronic lymphocytic leukemia (CLL) with a biased repertoire, including stereotyped BCRs. Thus, B1 B cells bearing restricted BCRs can become CLL during aging. Increased anti-thymocyte/Thy-1 autoreactive (ATA) BCR cells in the B1 B cell subset by transgenic expression yielded spontaneous ATA B-CLL/lymphoma incidence, enhanced by TCL1 transgenesis. In contrast, ATA B-CLL did not develop from other B cell subsets, even when the identical ATA BCR was expressed on a Thy-1 low/null background. Thus, both a specific BCR and B1 B cell context were important for CLL progression. Neonatal B1 B cells and their CLL progeny in aged mice continued to express moderately up-regulated c-Myc and down-regulated proapoptotic Bmf, unlike most mature B cells in the adult. Thus, there is a genetic predisposition inherent in B-1 development generating restricted BCRs and self-renewal capacity, with both features contributing to potential for progression to CLL.
Chronic lymphocytic leukemia (CLL) is a B-cell malignancy with a mature phenotype. In spite of its relatively indolent nature, no radical cure is as yet available. CLL is not associated with either a ...unique cytogenetic or a molecular defect, which might have been a potential therapeutic target. Instead, several factors are involved in disease development, such as environmental signals which interact with genetic abnormalities to promote survival, proliferation and an immune surveillance escape. Among these, PI3-Kinase signal pathway alterations are nowadays considered to be clearly important. The TCL1 gene, an AKT co-activator, is the cause of a mature T-cell leukemia, as well as being highly expressed in all B-CLL. A TCL1 transgenic mouse which reproduces leukemia with a distinct immunophenotype and similar to the course of the human B-CLL was developed several years ago and is widely used by many groups. This is a review of the CLL biology arising from work of many independent investigators who have used TCL1 transgenic mouse model focusing on pathogenetic, microenviroment and therapeutic targets.
We report here that in chronic lymphocytic leukemia (CLL), the propensity to generate clonal B cells has been acquired already at the hematopoietic stem cell (HSC) stage. HSCs purified from patients ...with CLL displayed lymphoid-lineage gene priming and produced a high number of polyclonal B cell progenitors. Strikingly, their maturation into B cells was restricted always to mono- or oligo-clones with CLL-like phenotype in xenogeneic recipients. These B cell clones were independent of the original CLL clones because they had their own immunoglobulin VDJ genes. Furthermore, they used preferentially VH genes frequently used in human CLL, presumably reflecting the role of B cell receptor signaling in clonal selection. These data suggest that HSCs can be involved in leukemogenesis even in mature lymphoid tumors.
► HSCs in CLL have cell-intrinsic propensity to generate clonal CLL-like B cells ► Abnormal karyotypes are not required for appearance of such B cell clones ► The majority of single HSCs in patients with CLL display lymphoid-lineage priming ► HSCs can be involved in oncogenesis even in mature lymphoid tumors
PDF
