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Chronic lymphocytic leukemia (CLL) arises from the clonal expansion of a CD5(+) B lymphocyte that is thought not to undergo intraclonal diversification. Using V(H)DJ(H) cDNA single strand conformation polymorphism analyses, we detected intraclonal mobility variants in 11 of 18 CLL cases. cDNA sequence analyses indicated that these variants represented unique point-mutations (1-35/patient). In nine cases, these mutations were unique to individual submembers of the CLL clone, although in two cases they occurred in a large percentage of the clonal submembers and genealogical trees could be identified. The diversification process responsible for these changes led to single nucleotide changes that favored transitions over transversions, but did not target A nucleotides and did not have the replacement/silent nucleotide change characteristics of antigen-selected B cells. Intraclonal diversification did not correlate with the original mutational load of an individual CLL case in that diversification was as frequent in CLL cells with little or no somatic mutations as in those with considerable mutations. Finally, CLL B cells that did not exhibit intraclonal diversification in vivo could be induced to mutate their V(H)DJ(H) genes in vitro after stimulation. These data indicate that a somatic mutation mechanism remains functional in CLL cells and could play a role in the evolution of the clone.

Simple Summary: Chronic lymphocytic leukemia (CLL) clones contain cells differing in age: recently born, proliferative (PF), intermediate (IF), and resting (RF) fractions. We used deuterium incorporation into newly synthesized DNA in leukemic cells from patients with CLL to refine the "aging" kinetics, characterizing additional fractions differing in surface membrane (sm) CXCR4/CD5 levels, i.e., CXCR4DimCD5Dim double dim fraction (DDF) and CXCR4BrightCD5Bright double bright fraction (DBF); and fractions differing in (sm)IgM and IgD densities. Although DDF was enriched in younger and DBF in older cells, PF and RF remained the youngest and oldest cells, respectively. Similarly, when using smIG to define subsets, cells with high smIgM and smIgD were the youngest, while cells with low smIgM and smIgD were the oldest. The youngest cells bore high levels of smIG and stimulating them via TLR9 and smIG yielded a phenotype that is more consistent with this in vivo observation. Finally, older cells were less sensitive to in vivo inhibition by ibrutinib. These data define additional CLL subpopulations; suggest that smIGs stimulation alone might not be responsible for the observed smIgM phenotype; and suggest that differential sensitivities of distinct fractions to the actions of ibrutinib might account, in part, for therapeutic relapse. Chronic lymphocytic leukemia (CLL) clones contain subpopulations differing in time since the last cell division ("age"): recently born, proliferative (PF; CXCR4DimCD5Bright), intermediate (IF; CXCR4IntCD5Int), and resting (RF; CXCR4BrightCD5Dim) fractions. Herein, we used deuterium (2H) incorporation into newly synthesized DNA in patients to refine the kinetics of CLL subpopulations by characterizing two additional CXCR4/CD5 fractions, i.e., double dim (DDF; CXCR4DimCD5Dim) and double bright (DBF; CXCR4BrightCD5Bright); and intraclonal fractions differing in surface membrane (sm) IgM and IgD densities. Although DDF was enriched in recently divided cells and DBF in older cells, PF and RF remained the most enriched in youngest and oldest cells, respectively. Similarly, smIgMHigh and smIgDHigh cells were the youngest, and smIgMLow and smIgDLow were the oldest, when using smIG levels as discriminator. Surprisingly, the cells closest to the last stimulatory event bore high levels of smIG, and stimulating via TLR9 and smIG yielded a phenotype more consistent with the in vivo setting. Finally, older cells were less sensitive to in vivo inhibition by ibrutinib. Collectively, these data define additional intraclonal subpopulations with divergent ages and phenotypes and suggest that BCR engagement alone is not responsible for the smIG levels found in vivo, and the differential sensitivity of distinct fractions to ibrutinib might account, in part, for therapeutic relapse. [ABSTRACT FROM AUTHOR]

Introduction: The leukemic cells of patients with chronic lymphocytic leukemia (CLL) are often unique, expressing remarkably similar IGHV-IGHD-IGHJ gene rearrangements, “stereotyped BCRs”. The B-cell receptors (BCRs) on CLL cells are also distinctive in often deriving from autoreactive B lymphocytes, leading to the assumption of a defect in immune tolerance. Results: Using bulk and single-cell immunoglobulin heavy and light chain variable domain sequencing, we enumerated CLL stereotype-like IGHV-IGHDIGHJ sequences (CLL-SLS) in B cells from cord blood (CB) and adult peripheral blood (PBMC) and bone marrow (BM of healthy donors. CLL-SLS were found at similar frequencies among CB, BM, and PBMC, suggesting that age does not influence CLL-SLS levels. Moreover, the frequencies of CLL-SLS did not differ among B lymphocytes in the BM at early stages of development, and only recirculating marginal zone B cells contained significantly higher CLL-SLS frequencies than other mature B-cell subpopulations. Although we identified CLL-SLS corresponding to most of the CLL major stereotyped subsets, CLL-SLS frequencies did not correlate with those found in patients. Interestingly, in CB samples, half of the CLL-SLS identified were attributed to two IGHV-mutated subsets. We also found satellite CLL-SLS among the same normal samples, and they were also enriched in naïve B cells but unexpectedly, these were ~10-fold higher than standard CLL-SLS. In general, IGHV-mutated CLL-SLS subsets were enriched among antigen-experienced B-cell subpopulations, and IGHVunmutated CLL-SLS were found mostly in antigen-inexperienced B cells. Nevertheless, CLL-SLS with an IGHV-mutation status matching that of CLL clones varied among the normal B-cell subpopulations, suggesting that specific CLL-SLS could originate from distinct subpopulations of normal B cells. Lastly, using single-cell DNA sequencing, we identified paired IGH and IGL rearrangements in normal B lymphocytes resembling those of stereotyped BCRs in CLL, although some differed from those in patients based on IG isotype or somatic mutation. Discussion: CLL-SLS are present in normal B-lymphocyte populations at all stages of development. Thus, despite their autoreactive profile they are not deleted by central tolerance mechanisms, possibly because the level of autoreactivity is not registered as dangerous by deletion mechanisms or because editing of L-chain variable genes occurred which our experimental approach could not identify. [ABSTRACT FROM AUTHOR]

Fludarabine may be effective in treating chronic lymphocytic leukemia that does not respond to chlorambucil. In a study of 509 patients, fludarabine resulted in higher response rates and longer remissions but did not improve overall survival rates.

Analyses of IGHV gene mutations in chronic lymphocytic leukemia (CLL) have had a major impact on the prognostication and treatment of this disease. A hallmark of IGHV-mutation status is that it very rarely changes clonally over time. Nevertheless, targeted and deep DNA sequencing of IGHV-IGHD-IGHJ regions has revealed intraclonal heterogeneity. We used a DNA sequencing approach that achieves considerable depth and minimizes artefacts and amplification bias to identify IGHV-IGHD-IGHJ subclones in patients with prolonged temporal follow-up. Our findings extend previous studies, revealing intraclonal IGHV-IGHD-IGHJ diversification in almost all CLL clones. Also, they indicate that some subclones with additional IGHV-IGHD-IGHJ mutations can become a large fraction of the leukemic burden, reaching numerical criteria for monoclonal B-cell lymphocytosis. Notably, the occurrence and complexity of post-transformation IGHV-IGHD-IGHJ heterogeneity and the expansion of diversified subclones are similar among U-CLL and M-CLL patients. The molecular characteristics of the mutations present in the parental, clinically dominant CLL clone (CDC) differed from those developing post-transformation (post-CDC). Post-CDC mutations exhibit significantly lower fractions of mutations bearing signatures of activation induced deaminase (AID) and of error-prone repair by Polη, and most of the mutations were not ascribable to those enzymes. Additionally, post-CDC mutations displayed a lower percentage of nucleotide transitions compared with transversions that was also not like the action of AID. Finally, the post-CDC mutations led to significantly lower ratios of replacement to silent mutations in VH CDRs and higher ratios in VH FRs, distributions different from mutations found in normal B-cell subsets undergoing an AID-mediated process. Based on these findings, we propose that post-transformation mutations in CLL cells either reflect a dysfunctional standard somatic mutational process or point to the action of another mutational process not previously associated with IG V gene loci. If the former option is the case, post-CDC mutations could lead to a lesser dependence on antigen dependent BCR signaling and potentially a greater influence of off-target, non-IG genomic mutations. Alternatively, the latter activity could add a new stimulatory survival/growth advantage mediated by the BCR through structurally altered FRs, such as that occurring by superantigen binding and stimulation. [ABSTRACT FROM AUTHOR]

Patient-derived xenograft models of chronic lymphocytic leukemia (CLL) can be created using highly immunodeficient animals, allowing analysis of primary tumor cells in an in vivo setting. However, unlike many other tumors, CLL B lymphocytes do not reproducibly grow in xenografts without manipulation, proliferating only when there is concomitant expansion of T cells. Here we show that in vitro pre-activation of CLL-derived T lymphocytes allows for a reliable and robust system for primary CLL cell growth within a fully autologous system that uses small numbers of cells and does not require pre-conditioning. In this system, growth of normal T and leukemic B cells follows four distinct temporal phases, each with characteristic blood and tissue findings. Phase 1 constitutes a period during which resting CLL B cells predominate, with cells aggregating at perivascular areas most often in the spleen. In Phase 2, T cells expand and provide T-cell help to promote B-cell division and expansion. Growth of CLL B and T cells persists in Phase 3, although some leukemic B cells undergo differentiation to more mature B-lineage cells (plasmablasts and plasma cells). By Phase 4, CLL B cells are for the most part lost with only T cells remaining. The required B-T cell interactions are not dependent on other human hematopoietic cells nor on murine macrophages or follicular dendritic cells, which appear to be relatively excluded from the perivascular lymphoid aggregates. Notably, the growth kinetics and degree of anatomic localization of CLL B and T cells is significantly influenced by intravenous versus intraperitoneal administration. Importantly, B cells delivered intraperitoneally either remain within the peritoneal cavity in a quiescent state, despite the presence of dividing T cells, or migrate to lymphoid tissues where they actively divide; this dichotomy mimics the human condition in that cells in primary lymphoid tissues and the blood are predominately resting, whereas those in secondary lymphoid tissues proliferate. Finally, the utility of this approach is illustrated by documenting the effects of a bispecific antibody reactive with B and T cells. Collectively, this model represents a powerful tool to evaluate CLL biology and novel therapeutics in vivo. [ABSTRACT FROM AUTHOR]

Within a period of just over a decade, managing chronic lymphocytic leukemia (CLL) has become more effective and yet more challenging than ever before. The important improvement in the treatment of CLL can be ascribed to the availability of many new options, mainly with the development of novel targeted therapies, such as ibrutinib, idelalisib, duvelisib and venetoclax. There are now newer tests that reliably define high-risk patients, and treatment plans can be tailored accordingly. Overall, this indeed is a new era in the treatment of patients with CLL. However, despite this progress, CLL remains an incurable disease and continues to remain challenging. In this brief review, the authors highlight the many great choices available to clinicians who manage patients with CLL and focus on the sequencing of these choices based on the available data. [ABSTRACT FROM AUTHOR]

To evaluate the potential of subcutaneous (SC) injections with anti-CD20 antibody veltuzumab in chronic lymphocytic leukemia (CLL), 21 patients received 80, 160, or 320 mg injections every 2 weeks × 4 doses (n = 11) or 160 or 320 mg twice-weekly × 16 doses (n = 10). Treatment was well tolerated with only occasional, mild-moderate, transient injection reactions. Lymphocytosis decreased in all patients (maximum decrease, 5–91%), with 12 patients obtaining >50% decreases. Of 14 patients with lymphadenopathy on CT imaging, 5 (36%) achieved 14–61% reductions (sum of perpendicular diameters). By NCI-WG criteria, two patients achieved partial responses (10%). SC veltuzumab appeared active in all dose groups, with no obvious exposure-response relationship, despite cumulative doses ranging from 320–5120 mg. Overall median progression-free survival was 7.7 months; three patients remained progression-free >1 year (2 ongoing at 2-year study completion). These data suggest further studies of SC veltuzumab in CLL are warranted. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukemia (CLL), the most common adult leukemia in the Western world, is primarily a disease of the elderly, with most patients =65 years of age and having at least one major comorbidity. Aggressive chemoimmunotherapy regimens recommended to achieve remission and improve survival in young, fit patients are often poorly tolerated in elderly and/or less physiologically fit ("unfit") patients, necessitating alternative treatment options. Although patient age, fitness, and comorbidities are key considerations in the selection of a treatment regimen, historically, clinical trials have been limited to young, fit patients by virtue of the ethical concerns associated with potential end organ toxic effects that could worsen comorbidities. However, the availability of new therapies promises a shift to a research paradigm that encompasses the identification of optimal treatments for elderly and unfit patients. Anti-CD20 monoclonal antibody therapy, which overall has improved response rates and survival in patients with CLL, has only recently been evaluated elderly and unfit patients. B cell-targeted agents such as the Bruton's tyrosine kinase inhibitor ibrutinib and the phosphatidylinositol 3-kinase inhibitor idelalisib are the first of a new generation of oral agents for CLL. Available clinical data suggest that these therapies have the potential to address the unmet need in elderly and unfit patients with CLL and result in clinical remission, and not merely symptom palliation and improved quality of life, which, by themselves, are also a reasonable goal. [ABSTRACT FROM AUTHOR]

B-cell chronic lymphocytic leukemia (B-CLL) patients expressing unmutated immunoglobulin heavy variable regions (IGHVs) use the IGHV1-69 B cell receptor (BCR) in 25% of cases. Since HIV-1 envelope gp41 antibodies also frequently use IGHV1-69 gene segments, we hypothesized that IGHV1-69 B-CLL precursors may contribute to the gp41 B cell response during HIV-1 infection. To test this hypothesis, we rescued 5 IGHV1-69 unmutated antibodies as heterohybridoma IgM paraproteins and as recombinant IgG1 antibodies from B-CLL patients, determined their antigenic specificities and analyzed BCR sequences. IGHV1-69 B-CLL antibodies were enriched for reactivity with HIV-1 envelope gp41, influenza, hepatitis C virus E2 protein and intestinal commensal bacteria. These IGHV1-69 B-CLL antibodies preferentially used IGHD3 and IGHJ6 gene segments and had long heavy chain complementary determining region 3s (HCDR3s) (≥21 aa). IGHV1-69 B-CLL BCRs exhibited a phenylalanine at position 54 (F54) of the HCDR2 as do rare HIV-1 gp41 and influenza hemagglutinin stem neutralizing antibodies, while IGHV1-69 gp41 antibodies induced by HIV-1 infection predominantly used leucine (L54) allelic variants. These results demonstrate that the B-CLL cell population is an expansion of members of the innate polyreactive B cell repertoire with reactivity to a number of infectious agent antigens including intestinal commensal bacteria. The B-CLL IGHV1-69 B cell usage of F54 allelic variants strongly suggests that IGHV1-69 B-CLL gp41 antibodies derive from a restricted B cell pool that also produces rare HIV-1 gp41 and influenza hemagglutinin stem antibodies. [ABSTRACT FROM AUTHOR]

We previously showed that approximately 60% of B chronic lymphocytic leukaemia (B-CLL) cells express surface CD180, an orphan receptor of the Toll-like receptor family. Here we investigated the ability of anti-CD180 monoclonal antibody (mAb) to induce activation, cell cycling, survival and signalling in B-CLL cells and normal B cells. Upon addition of anti-CD180 mAb, alone or in combination with anti-CD40 mAb or recombinant IL-4 (rIL-4), expression of CD86, Ki-67, uptake of DiOC, phosphorylation of signalling protein kinases and Ca flux were measured in B-CLL cells from untreated patients and normal B cells from age-matched volunteers. Normal B cells and approximately 50% of CD180 B-CLL clones responded to CD180 ligation by activation, cycling and increased survival comparable with, or superior to, those induced by anti-CD40 mAb or rIL-4 (Responder B-CLL). Non-responder CD180 B-CLL clones failed to respond to CD180 mAb and responded poorly to CD40 mAb and rIL-4. Anti-CD180 mAb induced phosphorylation of ZAP70/Syk, Erk, p38MAPK and Akt in normal B cells and Responder B-CLL cells. In contrast, Erk, p38MAPK and Akt were not phosphorylated in Non-responder B-CLL cells indicating a block in signalling and possible anergy. CD180 may provide powerful expansion and survival signals for Responder B-CLL cells and have an important prognostic value. [ABSTRACT FROM AUTHOR]

The humanized anti-CD52 monoclonal antibody alemtuzumab is an effective therapy for chronic lymphocytic leukemia (CLL). We examined the impact of alemtuzumab treatment after initial fludarabine treatment for feasibility and safety. Patients (N = 85) with previously untreated symptomatic CLL received fludarabine (25 mg/m2/day) for 5 days every 4 weeks for four cycles followed by 2 months of observation. Patients with stable disease or better response then received alemtuzumab 30 mg three times weekly for 6 weeks either intravenously (IV; cohort 1; N = 39) or subcutaneously (SC; cohort 2; N = 20). Of the 85 evaluable patients enrolled on our study, four (5%) attained a complete response (CR) and 43 (51%) attained a partial response after fludarabine induction for an overall response rate (ORR) of 55%. Thirty-nine patients received IV alemtuzumab for consolidation with improvement in CR to 27% and ORR to 73%. Twenty patients received SC alemtuzumab consolidation with improvement in CR to 17% and ORR to 69%. Toxicity from IV alemtuzumab included infusion-related reactions and infection. Mild local inflammation was common from SC alemtuzumab but there were virtually no systemic side effects. Nine of 59 (15%) patients had cytomegalovirus (CMV) infections; one patient died. The administration of alemtuzumab as consolidation therapy following an abbreviated fludarabine induction is feasible but requires close monitoring for CMV infection and other infectious events. [ABSTRACT FROM AUTHOR]

Purpose. Fludarabine is a renally excreted agent that is an effective treatment for chronic lymphocytic leukemia (CLL), a disease predominantly of the elderly. We sought to determine whether age, renal function or pretreatment hematologic status predicted toxicity of fludarabine treatment for CLL. Methods. We evaluated 192 patients with previously untreated B-cell CLL who were entered onto the fludarabine treatment arm (25 mg/m2 daily for 5 days every 28 days) of CALGB study 9011, an intergroup study with participation from SWOG, CTG/NCI-C and ECOG. Patients were required to have serum creatinine within 1.5 times normal. Hematologic indices and infections were recorded during the first 28-day cycle of treatment. A time-to-toxicity endpoint was evaluated over the entire course of fludarabine treatment. Creatinine clearance (CrClest) was estimated using serum creatinine, age and body mass index. Results. The median age was 64 years (range 37–87 years) and median CrClest was 62 ml/min (range 27–162 ml/min, interquartile range 52–79 ml/min). We found no association between age and incidence of hematologic toxicity or infection during the first cycle of treatment. There was a strong association between CrClest and the time-to-toxicity endpoint. Patients with CrClest below 80 ml/min had increased incidence of toxicity during their treatment course (P<0.0001). Pretreatment anemia, thrombocytopenia and Rai stage were highly associated with the incidence of neutrophil toxicity and grade III/IV hematologic toxicities during the first cycle of treatment (P<0.0001). Conclusions. Patient age was not an independent risk factor for fludarabine-related toxicity, but CrClest was associated with time to toxicity. [ABSTRACT FROM AUTHOR]

Deals with a study which reviewed the advances in the biologic and clinical research of chronic lymphocytic leukemia. Information on chronic lymphocytic leukemia; Epidemiology and etiology; Indications for initiating therapy.

The impact of initial fludarabine therapy on transformation to Richter syndrome (RS) or prolymphocytic leukemia (PLL) in patients with chronic lymphocytic leukemia (CLL) is uncertain. We studied the outcomes of 521 patients with CLL who were randomized to initial fludarabine (F), chlorambucil (C) or F + C therapy on an intergroup trial (CALGB 9011). RS developed in 34 (7%) patients and PLL in 10 (2%). RS and PLL occurred in 14 (7%) and three (2%) of 188 patients randomized to F; nine (5%) and four (2%) of 191 patients treated with C; and 11 (8% and three (2%) of 142 receiving F + C, respectively. Four percent of the 206 patients with Rai stage Ill/IV developed PLL, compared to only 1% of the 315 patients with Rai stage 1/11 (p=0.02) Initial fludarabine therapy in patients with CLL did not impact transformation to RS or PLL, nor were any other baseline characteristics predictive for such transformation in this series. [ABSTRACT FROM AUTHOR]

Although during the past two decades there has been considerable progress in our understanding of the pathophysiology of chronic lymphocytic leukemia (CLL) and in our ability to treat this disease, actual integration of the newly identified pathophysiological mechanisms has not occurred. This perspective essay identifies some of the questions which deserve to be addressed by clinicians and scientists involved in the study of CLL. The most important unresolved remaining issue, however, is the need for standardization of tests performed by commercial labs to assure the reliability and reproducibility of results of ZAP-70, CD38, IgVH gene mutation status and fluorescence in-situ hybridization (FISH) cytogenetics. [Copyright &y& Elsevier]

Presents a review article on the mechanisms of disease focusing on chronic lymphocytic leukemia. Comparison of the historical and current views of CLL; Normal B lymphocytes; CLL and the biology of leukemic lymphocytes; Biology of leukemic lymphocytes and the clinical course of the disease; Promoting factors in CLL; Unifying hypothesis for the development, growth, and evolution of CLL; Clinical implications for prognosis and management; New therapeutic approaches.

Editorial. Discusses the typical patient with chronic lymphocytic leukemia (CLL) and the inability to predict the clinical path of the CLL patient. Clinical staging systems for classifying patients into broad prognostic groups based on determinable features that seem to correlate with the gross tumor burden and its effect on the normal functions of the bone marrow; Division of cases into two subgroups on the basis of the presence or absence of somatic mutations in the specific immunoglobulin heavy-chain variable-region genes used by the leukemic cells; Topic of gene-expression profiling and a signaling-associated molecule, the zeta-chain-associated protein 70 (ZAP-70); Mention of studies, including that of Crespo and colleagues concerning the expression of ZAP-70 protein.

In chronic lymphocytic leukemia (CLL), the B cell receptor (BCR) plays a critical role in disease development and progression, as indicated by the therapeutic efficacy of drugs blocking BCR signaling. However, the mechanism(s) underlying BCR responsiveness are not completely defined. Selective engagement of membrane IgM or IgD on CLL cells, each coexpressed by more than 90% of cases, leads to distinct signaling events. Since both IgM and IgD carry the same antigen-binding domains, the divergent actions of the receptors are attributed to differences in immunoglobulin (Ig) structure or the outcome of signal transduction. We showed that IgM, not IgD, level and organization associated with CLL-cell birth rate and the type and consequences of BCR signaling in humans and mice. The latter IgM-driven effects were abrogated when BCR signaling was inhibited. Collectively, these studies demonstrated a critical, selective role for IgM in BCR signaling and B cell fate decisions, possibly opening new avenues for CLL therapy. [ABSTRACT FROM AUTHOR]

• An increased inflammatory signature exists in MBL, mediated mainly by monocytes. • This inflammatory signature is reduced in early-stage CLL, especially IGHV-mutated patients. • A similar increase in Th1 and cytotoxic CD4+ T cells is detected in both entities. • Tumor-supporting effects of monocytes are similarly observed in both entities. Several studies in chronic lymphocytic leukemia (CLL) patients have reported impaired immune cell functions, which contribute to tumor evasion and disease progression. However, studies on CLL-like monoclonal B-cell lymphocytosis (MBL) are scarce. In the study described here, we characterized the immune environment in 62 individuals with clinical MBL, 56 patients with early-stage CLL, and 31 healthy controls. Gene expression arrays and quantitative reverse transcription polymerase chain reaction were performed on RNA from CD4+ peripheral blood cells; serum cytokines were measured with immunoassays; and HLA-DR expression on circulating monocytes, as well as the percentages of Th1, cytotoxic, exhausted, and effector CD4+ T cells, were evaluated by flow cytometry. In addition, cell cultures of clonal B cells and CD14-enriched or -depleted cell fractions were performed. Strikingly, MBL and early-stage CLL differed in pro-inflammatory signatures. An increased inflammatory drive orchestrated mainly by monocytes was identified in MBL, which exhibited enhanced phagocytosis, pattern recognition receptors, interleukin-8 (IL8), HMGB1, and acute response signaling pathways and increased pro-inflammatory cytokines (in particular IL8, interferon γ [IFNγ], and tumor necrosis factor α). This inflammatory signature was diminished in early-stage CLL (reduced IL8 and IFNγ levels, IL8 signaling pathway, and monocytic HLA-DR expression compared with MBL), especially in those patients with mutations in IGHV genes. Additionally, CD4+ T cells of MBL and early-stage CLL exhibited a similar upregulation of Th1 and cytotoxic genes and expanded CXCR3+ and perforin+ CD4+ T cells, as well as PD1+ CD4+ T cells, compared with controls. Cell culture assays disclosed tumor-supporting effects of monocytes similarly observed in MBL and early-stage CLL. These novel findings reveal differences in the inflammatory environment between MBL and CLL, highlighting an active role for antigen stimulation in the very early stages of the disease, potentially related to malignant B-cell transformation. Image, graphical abstract [ABSTRACT FROM AUTHOR]

The previous edition of the consensus guidelines of the International Workshop on Chronic Lymphocytic Leukemia (iwCLL), published in 2008, has found broad acceptance by physicians and investigators caring for patients with CLL. Recent advances including the discovery of the genomic landscape of the disease, the development of genetic tests with prognostic relevance, and the detection of minimal residual disease (MRD), coupled with the increased availability of novel targeted agents with impressive efficacy, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. These recommendations include a revised version of the iwCLL response criteria, an update on the use of MRD status for clinical evaluation, and recommendations regarding the assessment and prophylaxis of viral diseases during management of CLL. [ABSTRACT FROM AUTHOR]

Amino acid replacement mutations in certain chronic lymphocytic leukemia (CLL) stereotyped B cell receptor (BCR) immunoglobulins (IGs) at defined positions within antigen-binding sites strongly imply antigen selection. Prime examples of this are CLL subset 4 BCR IGs using IGHV4-34/IGHD5-18/IGHJ6 and IGKV2-30/IGKJ2 rearrangements. Conspicuously, and unlike most CLL IGs, subset 4 IGs do not bind apoptotic cells. By testing the (auto)antigenic reactivities of subset 4 IGs toward viable lymphoid-lineage cells and specific autoantigens typically bound by IGHV4-34+ IGs, we found that IGs from both subset 4 and non-subset 4 IGHV4- 34-expressing CLL cases bound naïve B cells. However, only subset 4 IGs reacted with memory B cells. Furthermore, subset 4 IGs did not bind DNA nor i or I carbohydrate antigens that are common targets of IGHV4-34-utilizing antibodies in systemic lupus erythematosus and cold agglutinin disease, respectively. Notably, we found that subset 4 IG binding to memory B lymphocytes depends on an aspartic acid at position 66 of FR3 in the rearranged IGKV2-30 gene; this amino acid residue is acquired by somatic mutation. Our findings illustrate the importance of positive and negative selection criteria for structural elements in CLL IGs and suggest that autoantigens driving normal B cells to become subset 4 CLL cells differ from those driving IGHV4-34+ B cells in other diseases. [ABSTRACT FROM AUTHOR]

ROR1 is an oncoembryonic orphan-receptor found on chronic lymphocytic leukemia (CLL) B cells, but not on normal post-partum tissues. ROR1 is a receptor for Wnt5a that may complex with TCL1, a co-activator of AKT that is able to promote development of CLL. We found the CLL cells of a few patients expressed negligible ROR1 (ROR1Neg), but expressed TCL1A at levels comparable to those of samples that expressed ROR1 (ROR1Pos). Transcriptome analyses revealed that ROR1Neg cases generally could be distinguished from those that were ROR1Pos in unsupervised gene-expression clustering analysis. Gene-set enrichment analyses demonstrated that ROR1Neg CLL had lower expression and activation of AKT-signaling pathways relative to ROR1Pos CLL, similar to what was noted for leukemia that respectively developed in TCL1 versus ROR1xTCL1 transgenic mice. In contrast to its effect on ROR1Pos CLL, Wnt5a did not enhance the proliferation, chemotaxis, or survival of ROR1Neg CLL. We examined the CLL cells from 1,568 patients, which we randomly assigned to a training or validation set of 797 or 771 cases, respectively. Using recursive partitioning, we defined a threshold for ROR1-surface-expression that could segregate samples of the training set into ROR1-Hi versus ROR1-Lo subgroups that differed significantly in their median treatment free survival (TFS). Using this threshold, we found that ROR1-Hi cases had a significantly shorter median TFS and overall survival than ROR1-Lo cases in the validation set. These data demonstrate that expression of ROR1 may promote leukemia-cell activation and survival and enhance disease progression in patients with CLL. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukemia (CLL) is an incurable leukemia of unknown etiology. Multiple studies suggest that the structure of the variable domains of the surface IGs on these cells, and signaling through them, play key roles in developing the disease. Hence, CLL appears to be driven by antigen–BCR interactions, and identifying the selecting antigens involved in this process is an important goal. We studied the antigen-binding characteristics of 23 CLL-derived, recombinantly-expressed IGs with 5 pathogenic bacteria, determining that CLL IGs differ in bacterial reactivity based on IGHV gene use, mutation status, and association with IGHD and IGHJ genes (“stereotypy”). Although most bacterial-reactive IGs followed the paradigm that IGHV-unmutated IGs were more auto-/poly-reactive, several did not. In addition, some CLL IGs were bacterial mono-reactive, and these displayed IGKV use biases. These findings are consistent with CLL B cells being driven into the leukemogenic process by bacterial as well as auto- antigens. [ABSTRACT FROM AUTHOR]

ZAP-70 methylation 223 nucleotides downstream of transcription start (CpG+223) predicts outcome in chronic lymphocytic leukemia (CLL), but its impact relative to CD38 and ZAP-70 expression or immunoglobulin heavy chain variable region (IGHV) status is uncertain. Additionally, standardizing ZAP-70 expression analysis has been unsuccessful. CpG + 223 methylation was quantitatively determined in 295 untreated CLL cases using MassARRAY. Impact on clinical outcome vs CD38 and ZAP-70 expression and IGHV status was evaluated. Cases with low methylation (<20%) had significantly shortened time to first treatment (TT) and overall survival (OS) (P< .0001). For TT, low methylation defined a large subset of ZAP-70 protein-negative cases with significantly shortened TT (median, 8.0 vs 3.9 years for high vs low methylation; hazard ratio [HR] = 0.43; 95% confidence interval [Cl], 0.25-0.74). Conversely, 16 ZAP-70 protein-positive cases with high methylation had poor outcome (median, 1.1 vs 2.3 years for high vs low methylation; HR = 1.62; 95% Cl, 0.87-3.03). For OS, ZAP-70 methylation was the strongest risk factor; CD38 and ZAP-70 expression or IGHV status did not significantly improve OS prediction. A pyrosequencing assay was established that reproduced the MassARRAY data (k coefficient > 0.90). Thus, ZAP-70 CpG + 223 methylation represents a superior biomarker for TT and OS that can be feasibly measured, supporting its use in risk-stratifying CLL. [ABSTRACT FROM AUTHOR]

Clonal evolution occurs during the course of chronic lymphocytic leukemia (CLL) and activation-induced deaminase (AID) could influence this process. However, this possibility has been questioned in CLL because the number of circulating AID mRNA+ cells is exceedingly low; synthesis of AID protein by blood CLL cells has not been demonstrated; the full range of AID functions is lacking in unmutated CLL (U-CLL), and no prospective analysis linking AID expression and disease sever- ity has been reported. The results of the present study show that circulating CLL cells and those within secondary lymphoid tissues can make AID mRNA and protein. This production is related to cell division because more AID mRNA was detected in recently divided cells and AID protein was limited to the dividing fraction and was up-regulated on Induction of cell division. AID protein was functional because AID+ dividing cells exhibited more double-stranded DNA breaks, IGH class switching, and new IGHV-D-J mutations. Each of these actions was documented in U-CLL and mutated CLL (M-CLL). Furthermore, AID protein was associated with worse patient outcome and adverse cytogenetics. We conclude that the production of fully functional AID protein by U-CLL and M-CLL cells could be involved in clonal evolution of the disease. [ABSTRACT FROM AUTHOR]

Individual cytokines and groups of cytokines that might represent networks in chronic lymphocytic leukemia (CLL) were analyzed and their prognostic values determined. Serum levels of 23 cytokines were measured in 84 patients and 49 age-matched controls; 17 levels were significantly elevated in patients. Unsupervised hierarchical bicluster analysis identified 3 clusters (CLs) of highly correlated but differentially expressed cytokines: CL1 (CXCL9, CXCL10, CXCL11, CCL3, CCL4, CCL19, IL-5, IL-12, and IFNγ), CL2 (TNFα, IL-6, IL-8, and GM-CSF), and CL3 (IL-1β, IL-2, IL-4, IL-15, IL-17, and IFNα). Combination scores integrating expression of CL1/CL2 or CL1/CL3 strongly correlated (P < .005) with time-tofirst-treatment and overall survival (OS), respectively. Patients with the worst course had high CL1 and low CL2 or CL3 levels. Multivariate analysis revealed that CL1/CL2 combination score and immunoglobulin heavy chain variable region mutation status were independent prognostic indicators for time-to-first-treatment, whereas CL1/CL3 combination score and immunoglobulin heavy chain variable region mutation status were independent markers for OS. Thus, we identified groups of cytokines differentially expressed in CLL that are independent prognostic indicators of aggressive disease and OS. These findings indicate the value of multicytokine analyses for prognosis and suggest therapeutic strategies in CLL aimed at reducing CL1 and increasing CL2/CL3 cytokines. [ABSTRACT FROM AUTHOR]

Abstract: Cytogenetic abnormalities are important prognostic indicators in CLL. Historically, only interphase cytogenetics was clinically useful in CLL, because traditional mitogens are not effective mitotic stimulants. Recently, CpG-oligodeoxynucleotide (ODN) stimulation has shown effectiveness in CLL cells. The CLL Research Consortium tested the effectiveness and reproducibility of CpG-ODN stimulation for detecting chromosomally abnormal clones by five laboratories. More clonal abnormalities were observed after culture of CLL cells with CpG-ODN than with the traditional pokeweed mitogen plus 12-O-tetradecanoylphorbol-13-acetate (PWM+TPA). All clonal abnormalities in PWM+TPA cultures were observed in CpG-ODN cultures, whereas CpG-ODN identified some clones not found by PWM+TPA. CpG-ODN stimulation of one normal control sample and 12 CLL samples showed that, excepting clones of del(13q) in low frequencies and one translocation, results in all five laboratories were consistent, and all abnormalities were concordant with FISH. Abnormal clones in CLL were more readily detected with CpG-ODN stimulation than with traditional B-cell mitogens. With CpG-ODN stimulation, abnormalities were reproducible among cytogenetic laboratories. CpG-ODN did not appear to induce aberrations in cell culture, but did enhance detection of abnormalities and complexity in CLL. Because karyotypic complexity is prognostic and is not detectable by standard FISH analyses, stimulation with CpG-ODN is useful for identifying this additional prognostic factor in CLL. [ABSTRACT FROM AUTHOR]

Abstract: Five laboratories in the Chronic Lymphocytic Leukemia (CLL) Research Consortium (CRC) investigated standardizing and pooling of fluorescence in situ hybridization (FISH) results as a collaborative research project. This investigation used fixed bone marrow and blood cells available from previous conventional cytogenetic or FISH studies in two pilot studies, a one-day workshop, and proficiency test. Multiple FISH probe strategies were used to detect 6q-, 11q-, +12, 13q-, 17p-, and IGH rearrangements. Ten specimens were studied by participants who used their own probes (pilot study 1). Of 312 FISH interpretations, 224 (72%) were true-negative, 74 (24%) true-positive, 6 (2%) false-negative, and 8 (3%) false-positive. In pilot study no. 2, each participant studied two specimens using identical FISH probe sets to control for variation due to probe sets and probe strategies. Of 80 FISH interpretations, no false interpretations were identified. At a subsequent workshop, discussions produced agreement on scoring criteria. The proficiency test that followed produced no false-negative results and 4% (3/68) false-positive interpretations. Interpretation disagreements among laboratories were primarily attributable to inadequate normal cutoffs, inconsistent scoring criteria, and the use of different FISH probe strategies. Collaborative organizations that use pooled FISH results may wish to impose more conservative empiric normal cutoff values or use an equivocal range between the normal cutoff and the abnormal reference range to eliminate false-positive interpretations. False-negative results will still occur, and would be expected in low-percentage positive cases; these would likely have less clinical significance than false positive results. Individual laboratories can help by closely following rigorous quality assurance guidelines to ensure accurate and consistent FISH studies in their clinical practice and research. [ABSTRACT FROM AUTHOR]

All surface molecules depicted, but CCR7 and CTLA4, were greater in CXCR4 SP dim sp CD5 SP bright sp fractions, in terms of percent positive cells ( B A b ) or mean fluorescence intensity ( B B b ) or of both. Surface markers were analyzed by flow cytometry in CXCR4 SP dim sp CD5 SP bright sp (black) and CXCR4 SP bright sp CD5 SP dim sp (white) fractions. [Extracted from the article]

Chronic lymphocytic leukemia (CLL) represents the outgrowth of a CD5+ B cell. Its etiology is unknown. The structure of membrane Ig on CLL cells of unrelated patients can be remarkably similar. Therefore, antigen binding and stimulation could contribute to clonal selection and expansion as well as disease promotion. Initial studies suggest that CLL mAbs bind autoantigens. Since apoptosis can make autoantigens accessible for recognition by antibodies, and also create neo-epitopes by chemical modifications occurring naturally during this process, we sought to determine if CLL mAbs recognize autoantigens associated with apoptosis. In general, ~60% of CLL mAbs bound the surfaces of apoptotic cells, were polyreactive, and expressed unmutated IGHV. mAbs recognized two types of antigens: native molecules located within healthy cells, which relocated to the external cell surface during apoptosis; and/or neoantigens, generated by oxidation during the apoptotic process. Some of the latter epitopes are similar to those on bacteria and other microbes. Although most of the reactive mAbs were not mutated, the use of unmutated IGHV did not bestow autoreactivity automatically, since several such mAbs were not reactive. Particular IGHV and IGHV/D/J rearrangements contributed to autoantigen binding, although the presence and degree of reactivity varied based on specific structural elements. Thus, clonal expansion in CLL may be stimulated by autoantigens occurring naturally during apoptosis. These data suggest that CLL may derive from normal B cells whose function is to remove cellular debris, and also to provide a first line of defense against pathogens. [ABSTRACT FROM AUTHOR]

Due to its relatively slow clinical progression, B cell chronic lymphocytic leukemia (B-CLL) is classically described as a disease of accumulation rather than proliferation. However, evidence for various forms of clonal evolution suggests that B-CLL clones may be more dynamic than previously assumed. We used a nonradioactive, stable isotopic labeling method to measure B-CLL cell kinetics in vivo. Nineteen patients drank an aliquot of deuterated water (2H2O) daily for 84 days, and 2H incorporation into the deoxyribose moiety of DNA of newly divided B-CLL cells was measured by gas chromatography/mass spectrometry, during and after the labeling period. Birth rates were calculated from the kinetic profiles. Death rates were defined as the difference between calculated birth and growth rates. These analyses demonstrated that the leukemic cells of each patient had definable and often substantial birth rates, varying from 0.1% to greater than 1.0% of the entire clone per day. Those patients with birth rates greater than 0.35% per day were much more likely to exhibit active or to develop progressive disease than those with lower birth rates Thus, B-CLL is not a static disease that results simply from accumulation of long-lived lymphocytes. Rather, it is a dynamic process composed also of cells that proliferate and die, often at appreciable levels. The extent to which this turnover occurs has not been previously appreciated. A correlation between birth rates and disease activity and progression appears to exist, which may help identify patients at risk for worsening disease in advance of clinical deterioration. [ABSTRACT FROM AUTHOR]

B cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in western societies, and is currently incurable. B cells of some B-CLL patients are resistant to the anti-proliferative effects of transforming growth factor-β (TGF-β). Herein, we identified two mutations within the putative signal sequence of TGF-β type I receptor (TβR-I) gene of TGF-β-resistant B-CLL patients (i.e., a Leu12Gln substitution together with an in-frame single Ala deletion). Although TβR-I mutants were expressed to the cell surface and interacted normally with TGF-β-bound TβR-II, their expression significantly reduced gene transcription stimulated by TGF-β, suggesting a causal relationship in the development of TGF-β-resistant B-CLL. Screening of additional B-CLL patients solely for the presence of TβR-I signal sequence mutations showed that these mutations correlated with and predicted for B-CLL patient insensitivity to TGF-β. Our results demonstrate that TGF-β-resistant B-CLL is linked to signal sequence mutations within the TβR-I gene, and may eventually be employed as a prognostic indicator in B-CLL. [Copyright &y& Elsevier]

Background: The course of chronic lymphocytic leukemia (CLL) is variable. In aggressive disease, the CLL cells usually express an unmutated immunoglobulin heavy-chain variable-region gene (IgV) and the 70-kD zeta-associated protein (ZAP-70), whereas in indolent disease, the CLL cells usually express mutated IgV but lack expression of ZAP-70. Methods: We evaluated the CLL B cells from 307 patients with CLL for ZAP-70 and mutations in the rearranged IgV gene. We then investigated the association between the results and the time from diagnosis to initial therapy. Results: We found that ZAP-70 was expressed above a defined threshold level in 117 of the 164 patients with an unmutated IgV gene (71 percent), but in only 24 of the 143 patients with a mutated IgV gene (17 percent, P<0.001). Among the patients with ZAP-70–positive CLL cells, the median time from diagnosis to initial therapy in those who had an unmutated IgV gene (2.8 years) was not significantly different from the median time in those who had a mutated IgV gene (4.2 years, P=0.07). However, the median time from diagnosis to initial treatment in each of these groups was significantly shorter than the time in patients with ZAP-70–negative CLL cells who had either mutated or unmutated IgV genes (P<0.001). The median time from diagnosis to initial therapy among patients who did not have ZAP-70 was 11.0 years in those with a mutated IgV gene and 7.1 years in those with an unmutated IgV gene (P<0.001). Conclusions: Although the presence of an unmutated IgV gene is strongly associated with the expression of ZAP-70, ZAP-70 is a stronger predictor of the need for treatment in B-cell CLL. N Engl J Med 2004;351:893-901. [ABSTRACT FROM AUTHOR]