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The sensitivity of conventional techniques for reliable quantification of minimal/measurable residual disease (MRD) in chronic lymphocytic leukemia (CLL) is limited to MRD 10−4. Measuring MRD <10−4 could help to further distinguish between patients with CLL with durable remission and those at risk of early relapse. We herein present an academically developed immunoglobulin heavy-chain variable (IGHV) leader-based next-generation sequencing (NGS) assay for the quantification of MRD in CLL. We demonstrate, based on measurements in contrived MRD samples, that the linear range of detection and quantification of our assay reaches beyond MRD 10−5. If provided with sufficient DNA input, MRD can be detected down to MRD 10−6. There was high interassay concordance between measurements of the IGHV leader-based NGS assay and allele-specific oligonucleotide quantitative polymerase chain reaction (PCR) (r = 0.92 [95% confidence interval {CI}, 0.86-0.96]) and droplet digital PCR (r = 0.93 [95% CI, 0.88-0.96]) on contrived MRD samples. In a cohort of 67 patients from the CLL11 trial, using MRD 10−5 as a cutoff, undetectable MRD was associated with superior progression-free survival (PFS) and time to next treatment. More important, deeper MRD measurement allowed for additional stratification of patients with MRD <10−4 but ≥10−5. PFS of patients in this MRD range was significantly shorter, compared with patients with MRD <10−5 (hazard ratio [HR], 4.0 [95% CI, 1.6-10.3]; P = .004), but significantly longer, compared with patients with MRD ≥10−4 (HR, 0.44 [95% CI, 0.23-0.87]; P = .018). These results support the clinical utility of the IGHV leader-based NGS assay.

•An academically developed IGHV leader-based NGS assay can routinely detect and quantify MRD to 10−5and beyond in CLL.•MRD quantification below 10−4using this assay improves prognostic stratification in CLL.

The somatic hypermutation (SHM) status of the clonotypic immunoglobulin heavy variable (IGHV) gene is a critical biomarker for assessing the prognosis of patients with chronic lymphocytic leukemia (CLL). Importantly, independent studies have documented that IGHV SHM status is also a predictor of responses to therapy, including both chemoimmunotherapy (CIT) and novel, targeted agents. Moreover, immunogenetic analysis in CLL has revealed that different patients may express (quasi)identical, stereotyped B cell receptor immunoglobulin (BcR IG) and are classified into subsets based on this common feature. Patients in certain stereotyped subsets display consistent biology, clinical presentation, and outcome that are distinct from other patients, even with concordant IGHV gene SHM status. All of the above highlights the relevance of immunogenetic analysis in CLL, which is considered a cornerstone for accurate risk stratification and clinical decision making. Recommendations for robust immunogenetic analysis exist thanks to dedicated efforts by ERIC, the European Research Initiative on CLL, covering all test phases, from the pre-analytical and analytical to the post-analytical, pertaining to the analysis, interpretation, and reporting of the findings. That said, these recommendations apply to Sanger sequencing, which is increasingly being superseded by next generation sequencing (NGS), further underscoring the need for an update. Here, we present an overview of the clinical utility of immunogenetics in CLL and update our analytical recommendations with the aim to assist in the refined management of patients with CLL.

Ig gene (IG) clonality analysis has an important role in the distinction of benign and malignant B-cell lymphoid proliferations and is mostly performed with the conventional EuroClonality/BIOMED-2 multiplex PCR protocol and GeneScan fragment size analysis. Recently, the EuroClonality-NGS Working Group developed a method for next-generation sequencing (NGS)–based IG clonality analysis. Herein, we report the results of an international multicenter biological validation of this novel method compared with the gold standard EuroClonality/BIOMED-2 protocol, based on 209 specimens of reactive and neoplastic lymphoproliferations. NGS-based IG clonality analysis showed a high interlaboratory concordance (99%) and high concordance with conventional clonality analysis (98%) for the molecular conclusion. Detailed analysis of the individual IG heavy chain and kappa light chain targets showed that NGS-based clonality analysis was more often able to detect a clonal rearrangement or yield an interpretable result. NGS-based and conventional clonality analysis detected a clone in 96% and 95% of B-cell neoplasms, respectively, and all but one of the reactive cases were scored polyclonal. We conclude that NGS-based IG clonality analysis performs comparable to conventional clonality analysis. We provide critical parameters for interpretation and discuss a first step toward a quantitative scoring approach for NGS clonality results. Considering the advantages of NGS-based clonality analysis, including its high sensitivity and possibilities for accurate clonal comparison, this supports implementation in diagnostic practice.

Twenty years after landmark publications, there is a consensus that the somatic hypermutation (SHM) status of the clonotypic immunoglobulin heavy variable (IGHV) gene is an important cornerstone for accurate risk stratification and therapeutic decision-making in patients with chronic lymphocytic leukemia (CLL). The IGHV SHM status has traditionally been determined by conventional Sanger sequencing. However, NGS has heralded a new era in medical diagnostics and immunogenetic analysis is following this trend. There is indeed a growing demand for shifting practice and using NGS for IGHV gene SHM assessment, although it is debatable whether it is always justifiable, at least taking into account financial considerations for laboratories with limited resources. Nevertheless, as this analysis impacts on treatment decisions, standardization of both technical aspects, and data interpretation becomes essential. Also, the need for establishing new recommendations and providing dedicated education and training on NGS-based immunogenetics is greater than ever before. Here we address potential and challenges of NGS-based immunogenetics in CLL. We are convinced that this perspective helps the hematological community to better understand the pros and cons of this new technological development for CLL patient management.

B-cell prolymphocytic leukemia (B-PLL) is a rare hematological disorder whose underlying oncogenic mechanisms are poorly understood. Our cytogenetic and molecular assessments of 34 patients with B-PLL revealed several disease-specific features and potential therapeutic targets. The karyotype was complex (=3 abnormalities) in 73% of the patients and highly complex (=5 abnormalities) in 45%. The most frequent chromosomal aberrations were translocations involving MYC [t(MYC)] (62%), deletion (del)17p (38%), trisomy (tri)18 (30%), del13q (29%), tri3 (24%), tri12 (24%), and del8p (23%). Twenty-six (76%) of the 34 patients exhibited an MYC aberration, resulting from mutually exclusive translocations or gains. Whole-exome sequencing revealed frequent mutations in TP53, MYD88, BCOR, MYC, SF3B1, SETD2, CHD2, CXCR4, and BCLAF1. The majority of B-PLL used the IGHV3 or IGHV4 subgroups (89%) and displayed significantly mutated IGHV genes (79%). We identified 3 distinct cytogenetic risk groups: low risk (no MYC aberration), intermediate risk (MYC aberration but no del17p), and high risk (MYC aberration and del17p) (P = .0006). In vitro drug response profiling revealed that the combination of a B-cell receptor or BCL2 inhibitor with OTX015 (a bromodomain and extra-terminal motif inhibitor targeting MYC) was associated with significantly lower viability of B-PLL cells harboring a t(MYC). We concluded that cytogenetic analysis is a useful diagnostic and prognostic tool in B-PLL. Targeting MYC may be a useful treatment option in this disease.

B-cell prolymphocytic leukemia (B-PLL) is a rare hematological disorder whose underlying oncogenic mechanisms are poorly understood. Our cytogenetic and molecular assessments of 34 patients with B-PLL revealed several disease-specific features and potential therapeutic targets. The karyotype was complex (≥3 abnormalities) in 73% of the patients and highly complex (≥5 abnormalities) in 45%. The most frequent chromosomal aberrations were translocations involving MYC[t(MYC)] (62%), deletion (del)17p (38%), trisomy (tri)18 (30%), del13q (29%), tri3 (24%), tri12 (24%), and del8p (23%). Twenty-six (76%) of the 34 patients exhibited an MYCaberration, resulting from mutually exclusive translocations or gains. Whole-exome sequencing revealed frequent mutations in TP53, MYD88, BCOR, MYC, SF3B1, SETD2, CHD2, CXCR4, and BCLAF1. The majority of B-PLL used the IGHV3or IGHV4subgroups (89%) and displayed significantly mutated IGHVgenes (79%). We identified 3 distinct cytogenetic risk groups: low risk (no MYCaberration), intermediate risk (MYCaberration but no del17p), and high risk (MYCaberration and del17p) (P= .0006). In vitro drug response profiling revealed that the combination of a B-cell receptor or BCL2 inhibitor with OTX015 (a bromodomain and extra-terminal motif inhibitor targeting MYC) was associated with significantly lower viability of B-PLL cells harboring a t(MYC). We concluded that cytogenetic analysis is a useful diagnostic and prognostic tool in B-PLL. Targeting MYCmay be a useful treatment option in this disease.

Chronic lymphocytic leukemia (CLL), the most common adulthood leukemia in Western countries, is a very heterogeneous disease characterized by a peripheral accumulation of abnormal CD5+ B lymphocytes in the immune system. Despite new therapeutic developments, there remains an unmet medical need for CLL. Here, we demonstrate that the use of N-methylated thrombospondin-1 (TSP-1)–derived peptides is an efficient way to kill the malignant CLL cells, including those from high-risk individuals with poor clinical prognosis, del11q, del17p, 2p gain, or complex karyotype. PKT16, our hit N-methylated peptide, triggers the elimination of the leukemic cells, sparing the nontumor cells, including the hematopoietic precursors, and reduces the in vivo tumor burden of a CLL-xenograft mice model. A complementary analysis underscores the improved cytotoxic efficiency of PKT16 compared with the previously described TSP-1–derived probes, such as PKHB1. PKT16 elicits an original caspase-independent programmed necrotic mode of cell death, different from necroptosis or ferroptosis, implicating an intracellular Ca2+ deregulation that provokes mitochondrial damage, cell cycle arrest, and the specific death of the malignant CLL cells. The activation of the Gαi proteins and the subsequent drop of cyclic adenosine monophosphate levels and protein kinase A activity regulate this cytotoxic cascade. Remarkably, PKT16 induces the molecular hallmarks of immunogenic cell death, as defined by the calreticulin plasma membrane exposure and the release of adenosine triphosphate and high-mobility group box 1 protein from the dying CLL cells. Thus, PKT16 appears to be able to stimulate an anticancer in vivo immune response. Collectively, our results pave the way toward the development of an efficient strategy against CLL.

Chronic lymphocytic leukemia (CLL), the most common adulthood leukemia in Western countries, is a very heterogeneous disease characterized by a peripheral accumulation of abnormal CD5+B lymphocytes in the immune system. Despite new therapeutic developments, there remains an unmet medical need for CLL. Here, we demonstrate that the use of N-methylated thrombospondin-1 (TSP-1)–derived peptides is an efficient way to kill the malignant CLL cells, including those from high-risk individuals with poor clinical prognosis, del11q, del17p, 2p gain, or complex karyotype. PKT16, our hit N-methylated peptide, triggers the elimination of the leukemic cells, sparing the nontumor cells, including the hematopoietic precursors, and reduces the in vivo tumor burden of a CLL-xenograft mice model. A complementary analysis underscores the improved cytotoxic efficiency of PKT16 compared with the previously described TSP-1–derived probes, such as PKHB1. PKT16 elicits an original caspase-independent programmed necrotic mode of cell death, different from necroptosis or ferroptosis, implicating an intracellular Ca2+deregulation that provokes mitochondrial damage, cell cycle arrest, and the specific death of the malignant CLL cells. The activation of the Gαi proteins and the subsequent drop of cyclic adenosine monophosphate levels and protein kinase A activity regulate this cytotoxic cascade. Remarkably, PKT16 induces the molecular hallmarks of immunogenic cell death, as defined by the calreticulin plasma membrane exposure and the release of adenosine triphosphate and high-mobility group box 1 protein from the dying CLL cells. Thus, PKT16 appears to be able to stimulate an anticancer in vivo immune response. Collectively, our results pave the way toward the development of an efficient strategy against CLL.

The presence of mutations in the TP53gene is a powerful prognostic and predictive marker in chronic lymphocytic leukemia (CLL). Widespread use of NGS has enabled the detection of variants ≤10 % variant allelic frequency (low-VAF variants); however, the overall reliability and reproducibility of NGS techniques to identify such variants have been questioned repeatedly. Individual studies using sensitive, custom NGS-based assays have mostly demonstrated the shortened overall survival (OS) and event-free survival in patients with low-VAF TP53variants treated with chemoimmunotherapy (CIT) regimens with median survival ranging between that of TP53 variants >10 % VAF (high-VAF) and wild-type TP53(wt- TP53).

Assessment of clonality, marker identification and measurement of minimal residual disease (MRD) of immunoglobulin (IG) and T cell receptor (TR) gene rearrangements in lymphoid neoplasms using next-generation sequencing (NGS) is currently under intensive development for use in clinical diagnostics. So far, however, there is a lack of suitable quality control (QC) options with regard to standardisation and quality metrics to ensure robust clinical application of such approaches. The EuroClonality-NGS Working Group has therefore established two types of QCs to accompany the NGS-based IG/TR assays. First, a central polytarget QC (cPT-QC) is used to monitor the primer performance of each of the EuroClonality multiplex NGS assays; second, a standardised human cell line-based DNA control is spiked into each patient DNA sample to work as a central in-tube QC and calibrator for MRD quantification (cIT-QC). Having integrated those two reference standards in the ARResT/Interrogate bioinformatic platform, EuroClonality-NGS provides a complete protocol for standardised IG/TR gene rearrangement analysis by NGS with high reproducibility, accuracy and precision for valid marker identification and quantification in diagnostics of lymphoid malignancies.

One of the hallmarks of B lymphoid malignancies is a B cell clone characterized by a unique footprint of clonal immunoglobulin (IG) gene rearrangements that serves as a diagnostic marker for clonality assessment. The EuroClonality/BIOMED-2 assay is currently the gold standard for analyzing IG heavy chain (IGH)and κ light chain (IGK) gene rearrangements of suspected B cell lymphomas. Here, the EuroClonality-NGS Working Group presents a multicentre technical feasibility study of a novel approach involving next-generation sequencing (NGS) of IGH and IGK loci rearrangements that is highly suitable for detecting IG gene rearrangements in frozen and formalin-fixed paraffin-embedded tissue specimens. By employing gene-specific primers for IGH and IGK amplifying smaller amplicon sizes in combination with deep sequencing technology, this NGS-based IG clonality analysis showed robust performance, even in DNA samples of suboptimal DNA integrity, and a high clinical sensitivity for the detection of clonal rearrangements. Bioinformatics analyses of the high-throughput sequencing data with ARResT/Interrogate, a platform developed within the EuroClonality-NGS Working Group, allowed accurate identification of clonotypes in both polyclonal cell populations and monoclonal lymphoproliferative disorders. This multicentre feasibility study is an important step towards implementation of NGS-based clonality assessment in clinical practice, which will eventually improve lymphoma diagnostics.

Amplicon-based next-generation sequencing (NGS) of immunoglobulin (IG) and T-cell receptor (TR) gene rearrangements for clonality assessment, marker identification and quantification of minimal residual disease (MRD) in lymphoid neoplasms has been the focus of intense research, development and application. However, standardization and validation in a scientifically controlled multicentre setting is still lacking. Therefore, IG/TR assay development and design, including bioinformatics, was performed within the EuroClonality-NGS working group and validated for MRD marker identification in acute lymphoblastic leukaemia (ALL). Five EuroMRD ALL reference laboratories performed IG/TR NGS in 50 diagnostic ALL samples, and compared results with those generated through routine IG/TR Sanger sequencing. A central polytarget quality control (cPT-QC) was used to monitor primer performance, and a central in-tube quality control (cIT-QC) was spiked into each sample as a library-specific quality control and calibrator. NGS identified 259 (average 5.2/sample, range 0–14) clonal sequences vs. Sanger-sequencing 248 (average 5.0/sample, range 0–14). NGS primers covered possible IG/TR rearrangement types more completely compared with local multiplex PCR sets and enabled sequencing of bi-allelic rearrangements and weak PCR products. The cPT-QC showed high reproducibility across all laboratories. These validated and reproducible quality-controlled EuroClonality-NGS assays can be used for standardized NGS-based identification of IG/TR markers in lymphoid malignancies.

Nodal marginal zone lymphoma (NMZL) is a rare form of indolent small B-cell lymphoma which has only been clearly identified in the last 2 decades and which to date remains incurable. Progress in therapeutic management has been slow, largely due to the very small number of patients treated and the heterogeneity of treatments administered; thus, standard-of-care treatment is currently nonspecific for this lymphoma entity. In this review, treatments routinely used to manage adult NMZL patients are presented, principally based on immunochemotherapy (when treatment is needed). Biological research behind the key axes of agents currently under development is described; development of novel agents is heavily based on data from gene profiling and genome-wide sequencing research, uncovering a number of critical deregulated pathways specific to NMZL tumors. These include B-cell receptor, JAK/STAT, NF-κB, NOTCH, and Toll-like receptor signaling pathways, as well as intracellular processes such as the cell cycle, chromatin remodeling, and transcriptional regulation in terms of epigenetic modifiers, histones, or transcriptional co-repressors, along with immune escape via T-cell–mediated tumor surveillance. These pathways are examined in detail and a projection of how the field may evolve in the near future for an efficient personalized treatment approach for NMZL patients is presented.

Nodal marginal zone lymphoma (NMZL) is a rare form of indolent small B-cell lymphoma which has only been clearly identified in the last 2 decades and which to date remains incurable. Progress in therapeutic management has been slow, largely due to the very small number of patients treated and the heterogeneity of treatments administered; thus, standard-of-care treatment is currently nonspecific for this lymphoma entity. In this review, treatments routinely used to manage adult NMZL patients are presented, principally based on immunochemotherapy (when treatment is needed). Biological research behind the key axes of agents currently under development is described; development of novel agents is heavily based on data from gene profiling and genome-wide sequencing research, uncovering a number of critical deregulated pathways specific to NMZL tumors. These include B-cell receptor, JAK/STAT, NF-κB, NOTCH, and Toll-like receptor signaling pathways, as well as intracellular processes such as the cell cycle, chromatin remodeling, and transcriptional regulation in terms of epigenetic modifiers, histones, or transcriptional co-repressors, along with immune escape via T-cell–mediated tumor surveillance. These pathways are examined in detail and a projection of how the field may evolve in the near future for an efficient personalized treatment approach for NMZL patients is presented.

Although TP53, NOTCH1, and SF3B1mutations may impair prognosis of patients with chronic lymphocytic leukemia (CLL) receiving frontline therapy, the impact of these mutations or any other, alone or in combination, remains unclear at relapse. The genome of 114 relapsed/refractory patients included in prospective trials was screened using targeted next-generation sequencing of the TP53, SF3B1, ATM, NOTCH1, XPO1, SAMHD1, MED12, BIRC3, and MYD88genes. We performed clustering according to both number and combinations of recurrent gene mutations. The number of genes affected by mutation was ≥2, 1, and 0 in 43 (38%), 49 (43%), and 22 (19%) respectively. Recurrent combinations of ≥2 mutations of TP53, SF3B1, and ATMwere found in 22 (19%) patients. This multiple-hit profile was associated with a median progression-free survival of 12 months compared with 22.5 months in the remaining patients (P= .003). Concurrent gene mutations are frequent in patients with relapsed/refractory CLL and are associated with worse outcome.

Although TP53, NOTCH1, and SF3B1 mutations may impair prognosis of patients with chronic lymphocytic leukemia (CLL) receiving frontline therapy, the impact of these mutations or any other, alone or in combination, remains unclear at relapse. The genome of 114 relapsed/refractory patients included in prospective trials was screened using targeted next-generation sequencing of the TP53, SF3B1, ATM, NOTCH1, XPO1, SAMHD1, MED12, BIRC3, and MYD88 genes. We performed clustering according to both number and combinations of recurrent gene mutations. The number of genes affected by mutation was ≥2, 1, and 0 in 43 (38%), 49 (43%), and 22 (19%) respectively. Recurrent combinations of ≥2 mutations of TP53, SF3B1, and ATM were found in 22 (19%) patients. This multiple-hit profile was associated with a median progression-free survival of 12 months compared with 22.5 months in the remaining patients (P = .003). Concurrent gene mutations are frequent in patients with relapsed/refractory CLL and are associated with worse outcome.

Chronic lymphocytic leukemia (CLL) is characterized by a highly variable clinical course with 2 extreme subsets: indolent, ZAP70−and mutated immunoglobulin heavy chain gene (M-CLL); and aggressive, ZAP70+and unmutated immunoglobulin heavy chain (UM-CLL). Given the long-term suspicion of antigenic stimulation as a primum movensin the disease, the role of the B-cell receptor has been extensively studied in various experimental settings; albeit scarcely in a comparative dynamic proteomic approach. Here we use a quantitative 2-dimensional fluorescence difference gel electrophoresis technology to compare 48 proteomic profiles of the 2 CLL subsets before and after anti-IgM ligation. Differentially expressed proteins were subsequently identified by mass spectrometry. We show that unstimulated M- and UM-CLL cells display distinct proteomic profiles. Furthermore, anti-IgM stimulation induces a specific proteomic response, more pronounced in the more aggressive CLL. Statistical analyses demonstrate several significant protein variations according to stimulation conditions. Finally, we identify an intermediate form of M-CLL cells, with an indolent profile (ZAP70−) but sharing aggressive proteomic profiles alike UM-CLL cells. Collectively, this first quantitative and dynamic proteome analysis of CLL further dissects the complex molecular pathway after B-cell receptor stimulation and depicts distinct proteomic profiles, which could lead to novel molecular stratification of the disease.

Chronic lymphocytic leukemia (CLL) is characterized by a highly variable clinical course with 2 extreme subsets: indolent, ZAP70− and mutated immunoglobulin heavy chain gene (M-CLL); and aggressive, ZAP70+ and unmutated immunoglobulin heavy chain (UM-CLL). Given the long-term suspicion of antigenic stimulation as a primum movens in the disease, the role of the B-cell receptor has been extensively studied in various experimental settings; albeit scarcely in a comparative dynamic proteomic approach. Here we use a quantitative 2-dimensional fluorescence difference gel electrophoresis technology to compare 48 proteomic profiles of the 2 CLL subsets before and after anti-IgM ligation. Differentially expressed proteins were subsequently identified by mass spectrometry. We show that unstimulated M- and UM-CLL cells display distinct proteomic profiles. Furthermore, anti-IgM stimulation induces a specific proteomic response, more pronounced in the more aggressive CLL. Statistical analyses demonstrate several significant protein variations according to stimulation conditions. Finally, we identify an intermediate form of M-CLL cells, with an indolent profile (ZAP70−) but sharing aggressive proteomic profiles alike UM-CLL cells. Collectively, this first quantitative and dynamic proteome analysis of CLL further dissects the complex molecular pathway after B-cell receptor stimulation and depicts distinct proteomic profiles, which could lead to novel molecular stratification of the disease.

Long-term responses have been reported after autologous stem cell transplantation (ASCT) for chronic lymphocytic leukemia (CLL). We conducted a prospective, randomized trial of ASCT in previously untreated CLL patients. We enrolled 241 patients < 66 years of age with Binet stage B or C CLL. They received 3 courses of mini-CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone/prednisolone) and then 3 courses of fludarabine. Patients in complete response (CR) were then randomized to ASCT or observation, whereas the other patients were randomized to dexamethasone, high-dose aracytin, cisplatin (DHAP) salvage followed by either ASCT or 3 courses of fludarabine plus cyclophosphamide (FC). The primary end point was event-free survival (EFS). After up-front treatment, 105 patients entered CR and were randomized between ASCT (n = 52) and observation (n = 53); their respective 3-year EFS rates were 79.8% and 35.5%; the adjusted hazard ratio was 0.3 (95% CI: 0.1-0.7; P= .003). Ninety-four patients who did not enter CR were randomized between ASCT (n = 46) and FC (n = 48); their respective 3-year EFS rates were 48.9% and 44.4%, respectively; the adjusted hazard ratio was 1.7 (95% CI: 0.9-3.2; P= .13). No difference in overall survival was found between the 2 response subgroups. In young CLL patients in CR, ASCT consolidation markedly delayed disease progression. No difference was observed between ASCT and FC in patients requiring DHAP salvage.

Long-term responses have been reported after autologous stem cell transplantation (ASCT) for chronic lymphocytic leukemia (CLL). We conducted a prospective, randomized trial of ASCT in previously untreated CLL patients. We enrolled 241 patients < 66 years of age with Binet stage B or C CLL. They received 3 courses of mini-CHOP (cyclophosphamide, hydroxydaunorubicin, oncovin, and prednisone/prednisolone) and then 3 courses of fludarabine. Patients in complete response (CR) were then randomized to ASCT or observation, whereas the other patients were randomized to dexamethasone, high-dose aracytin, cisplatin (DHAP) salvage followed by either ASCT or 3 courses of fludarabine plus cyclophosphamide (FC). The primary end point was event-free survival (EFS). After up-front treatment, 105 patients entered CR and were randomized between ASCT (n = 52) and observation (n = 53); their respective 3-year EFS rates were 79.8% and 35.5%; the adjusted hazard ratio was 0.3 (95% CI: 0.1-0.7; P = .003). Ninety-four patients who did not enter CR were randomized between ASCT (n = 46) and FC (n = 48); their respective 3-year EFS rates were 48.9% and 44.4%, respectively; the adjusted hazard ratio was 1.7 (95% CI: 0.9-3.2; P = .13). No difference in overall survival was found between the 2 response subgroups. In young CLL patients in CR, ASCT consolidation markedly delayed disease progression. No difference was observed between ASCT and FC in patients requiring DHAP salvage.

ZAP‐70, after being considered as a potential surrogate for VH mutational status, has seen its own prognostic value emerge. We aimed at standardizing a simple, fast, and reproducible flow cytometry method.AntiZAP‐70 antibody 2F3.2 was used with indirect labeling and secondary anti‐IgG2a antibody. The reference values for the expression of the results were determined on 45 normal blood samples. ZAP‐70 protein expression was investigated in 192 CLL samples. The indirect technique was compared with FITC‐conjugated 2F3.2 clone, and with clone 1E7.2‐FITC, ‐PE or ‐AlexaFluor 488.Using FITC or PE‐conjugated antibodies, 2F3.2 and 1E7.2 clones allowed a much less adequate discrimination between positive and negative cells and discordant cases were most likely true negative cases. Using the AlexaFluor 488 conjugated 1E7.2 clone, the discordant cases were mostly negative with the conjugated antibody and positive with the 2F3.2 clone but Western blotting or RNA microarray confirmed discordant cases were false negative with the conjugated antibody. Subsequently, recommendations were used by 13 centers participating in an interlaboratory quality control protocol. The use of MFI ratio appeared to be more reliable.Results suggested that slight differences in the procedure had little impact on the interpretation in characteristic cases; however, careful interpretation was required for values close to threshold. © 2006 International Society for Analytical Cytology

The chronic lymphocytic leukemia (CLL) immunoglobulin repertoire is biased and characterized by the existence of subsets of cases with closely homologous (“stereotyped”) complementarity-determining region 3 (CDR3) sequences. In the present series, 201 (21.9%) of 916 patients with CLL expressed IGHV genes that belonged to 1 of 48 different subsets of sequences with stereotyped heavy chain (H) CDR3. Twenty-six subsets comprised 3 or more sequences and were considered “confirmed.” The remaining subsets comprised pairs of sequences and were considered “potential”; public database CLL sequences were found to be members of 9 of 22 “potential” subsets, thereby allowing us to consider them also “confirmed.” The chance of belonging to a subset exceeded 35% for unmutated or selected IGHV genes (eg, IGHV1-69/3-21/4-39). Comparison to non-CLL public database sequences showed that HCDR3 restriction is “CLL-related.” CLL cases with selected stereotyped immunoglobulins (IGs) were also found to share unique biologic and clinical features. In particular, cases expressing stereotyped IGHV4-39/IGKV1-39-1D-39 and IGHV4-34/IGKV2-30 were always IgG-switched. In addition, IGHV4-34/IGKV2-30 patients were younger and followed a strikingly indolent disease, contrasting other patients (eg, those expressing IGHV3-21/IGLV3-21) who experienced an aggressive disease, regardless of IGHV mutations. These findings suggest that a particular antigen-binding site can be critical in determining the clinical features and outcome for at least some CLL patients.

The chronic lymphocytic leukemia (CLL) immunoglobulin repertoire is biased and characterized by the existence of subsets of cases with closely homologous (“stereotyped”) complementarity-determining region 3 (CDR3) sequences. In the present series, 201 (21.9%) of 916 patients with CLL expressed IGHV genes that belonged to 1 of 48 different subsets of sequences with stereotyped heavy chain (H) CDR3. Twenty-six subsets comprised 3 or more sequences and were considered “confirmed.” The remaining subsets comprised pairs of sequences and were considered “potential”; public database CLL sequences were found to be members of 9 of 22 “potential” subsets, thereby allowing us to consider them also “confirmed.” The chance of belonging to a subset exceeded 35% for unmutated or selected IGHV genes (eg, IGHV1-69/3-21/4-39). Comparison to non-CLL public database sequences showed that HCDR3 restriction is “CLL-related.” CLL cases with selected stereotyped immunoglobulins (IGs) were also found to share unique biologic and clinical features. In particular, cases expressing stereotyped IGHV4-39/IGKV1-39-1D-39and IGHV4-34/IGKV2-30were always IgG-switched. In addition, IGHV4-34/IGKV2-30patients were younger and followed a strikingly indolent disease, contrasting other patients (eg, those expressing IGHV3-21/IGLV3-21) who experienced an aggressive disease, regardless of IGHV mutations. These findings suggest that a particular antigen-binding site can be critical in determining the clinical features and outcome for at least some CLL patients.

Although the zeta-associated protein of 70 kDa (ZAP-70) is overexpressed in patients with chronic lymphocytic leukemia (CLL) displaying unmutated IGVH genes and poor prognosis, a previous microarray study from our group identified overexpression of LPL and ADAM29 genes among unmutated and mutated CLL, respectively. To assess the prognostic value of these genes, we quantified their expression by real-time quantitative polymerase chain reaction (PCR) in a cohort of 127 patients with CLL and correlated this with clinical outcome, IGVH mutational status, and ZAP-70 protein expression. IGVH mutational status, ZAP-70, and the LPL and ADAM29 mRNA ratios (L/A ratio) were predictive of event-free survival for the whole cohort and for patients with stage A disease. In patients in stage B and C, the L/A ratio was an independent prognostic factor, whereas ZAP-70 did not predict survival. Simultaneous usage of the L/A ratio and ZAP-70 expression allowed an almost perfect (99%) assessment of the IGVH status in the 80% of patients with concordant results (L/A+, ZAP-70+ or L/A-, ZAP-70-). LPL and ADAM29 gene expression could also be determined by a simple competitive multiplex reverse transcription PCR assay. Overall, quantification of LPL and ADAM29 gene expression is a strong prognostic indicator in CLL, providing better prognostic assessment than ZAP-70 in advanced stages of the disease. (Blood. 2005;106:650-657)

Although the zeta-associated protein of 70 kDa (ZAP-70) is overexpressed in patients with chronic lymphocytic leukemia (CLL) displaying unmutated IGVHgenes and poor prognosis, a previous microarray study from our group identified overexpression of LPLand ADAM29genes among unmutated and mutated CLL, respectively. To assess the prognostic value of these genes, we quantified their expression by real-time quantitative polymerase chain reaction (PCR) in a cohort of 127 patients with CLL and correlated this with clinical outcome, IGVHmutational status, and ZAP-70 protein expression. IGVHmutational status, ZAP-70, and the LPLand ADAM29mRNA ratios (L/A ratio) were predictive of event-free survival for the whole cohort and for patients with stage A disease. In patients in stage B and C, the L/A ratio was an independent prognostic factor, whereas ZAP-70 did not predict survival. Simultaneous usage of the L/A ratio and ZAP-70 expression allowed an almost perfect (99%) assessment of the IGVHstatus in the 80% of patients with concordant results (L/A+, ZAP-70+or L/A-, ZAP-70-). LPLand ADAM29gene expression could also be determined by a simple competitive multiplex reverse transcription PCR assay. Overall, quantification of LPLand ADAM29gene expression is a strong prognostic indicator in CLL, providing better prognostic assessment than ZAP-70 in advanced stages of the disease. (Blood. 2005;106:650-657)

Posttransplantation lymphoproliferative disorders (PTLDs) are a spectrum of lymphoid proliferations, occurring in immunosuppressed organ transplant recipients. They comprise early lesions, polymorphic (P-PTLD), monomorphic (M-PTLD), and Hodgkin/Hodgkin-like lymphoma PTLD (HL-PTLD) lesions. Most of them are associated with Epstein-Barr virus (EBV). Little is known about their genetic changes.

We studied immunoglobulin variable heavy-chain (IGHV) repertoire and mutational status in 553 patients with chronic lymphocytic leukemia (CLL) from the Mediterranean area to gain insight into the potential pathogenetic role of antigenic stimulation. The most commonly represented IGHV genes mirrored the usage of normal B cells, with the exception of IGHV1-18, IGHV3-30.3, and IGHV4-59 that were underrepresented. The IGHV3-21 gene, frequently expressed in Northern European CLL, was present only in 16 cases (2.9%). Based on HCDR3 cluster analysis, cases using IGHV3-21 could be grouped in 2 subsets of similar frequency. The first one (7 of 16 cases) carried a similar HCDR3 amino acid sequence (common-HCDR3 subset), virtually identical to the Scandinavian IGHV3-21 CLL. These cases used the IGHJ6gene; 4 of 7 were unmutated; 6 of 7 carried the Vλ2-14 (IGLV3-21) light-chain gene with a similar LCDR3. All expressed CD38 and had a progressive disease. The second subset (9 of 16) was characterized by heterogeneous HCDR3 rearrangements (nonhomogeneous-HCDR3 subset), diverse IGHJ and IGV light-chain gene usage, variable IGHV mutational status (5 of 9 unmutated), variable CD38 expression, and variable clinical course (4 of 9 progressed). The first subset suggests a potential antigenic element rarely encountered in the Mediterranean area, possibly responsible for a negative outcome. The second subset may reflect the physiologic heterogeneity of expression of IGHV3-21 rearrangements in the normal repertoire and is characterized by a variable clinical outcome. (Blood. 2005;105:1678-1685)

We studied immunoglobulin variable heavy-chain (IGHV) repertoire and mutational status in 553 patients with chronic lymphocytic leukemia (CLL) from the Mediterranean area to gain insight into the potential pathogenetic role of antigenic stimulation. The most commonly represented IGHV genes mirrored the usage of normal B cells, with the exception of IGHV1-18, IGHV3-30.3, and IGHV4-59 that were underrepresented. The IGHV3-21 gene, frequently expressed in Northern European CLL, was present only in 16 cases (2.9%). Based on HCDR3 cluster analysis, cases using IGHV3-21 could be grouped in 2 subsets of similar frequency. The first one (7 of 16 cases) carried a similar HCDR3 amino acid sequence (common-HCDR3 subset), virtually identical to the Scandinavian IGHV3-21 CLL. These cases used the IGHJ6 gene; 4 of 7 were unmutated; 6 of 7 carried the Vλ2-14 (IGLV3-21) light-chain gene with a similar LCDR3. All expressed CD38 and had a progressive disease. The second subset (9 of 16) was characterized by heterogeneous HCDR3 rearrangements (nonhomogeneous-HCDR3 subset), diverse IGHJ and IGV light-chain gene usage, variable IGHV mutational status (5 of 9 unmutated), variable CD38 expression, and variable clinical course (4 of 9 progressed). The first subset suggests a potential antigenic element rarely encountered in the Mediterranean area, possibly responsible for a negative outcome. The second subset may reflect the physiologic heterogeneity of expression of IGHV3-21 rearrangements in the normal repertoire and is characterized by a variable clinical outcome. (Blood. 2005;105:1678-1685)

B-cell chronic lymphoid leukemia (BCLL) is a highly heterogeneous human malignancy, presumably reflecting specific molecular alterations in gene expression and protein activity that are thought to underlie the variable disease outcome. Most B-CLL cell samples undergo apoptotic death in response to DNA damage. However, a clinically distinct aggressive subset of B-CLL is completely resistant in vitro to irradiation-induced apoptosis. We therefore addressed 2 series of microarray analyses on 4 sensitive and 3 resistant B-CLL cell samples and compared their gene expression patterns before and after apoptotic stimuli. Data analysis pointed out 16 genes whose expression varied at least 2-fold specifically in resistant cells. We validated these selected genes by real-time quantitative reverse transcription–polymerase chain reaction (RT-PCR) on 7 microarray samples and confirmed their altered expression level on 15 additional B-CLL cell samples not included in the microarray analysis. In this manner, in 11 sensitive and 11 resistant B-CLL cell samples tested, 13 genes were found to be specific for all resistant samples: nuclear orphan receptor TR3, major histocompatibility complex (MHC) class II glycoprotein HLA-DQA1, mtmr6, c-myc, c-rel, c-IAP1, mat2A, and fmodwere up-regulated, whereas MIP1a/GOS19-1homolog, stat1, blk, hsp27, and ech1were down-regulated. In some cases, the expression profile may be dependent on the status of p53. Some of these genes encode general apoptotic factors but also exhibit lymphoid cell specificities that could potentially be linked to the development of lymphoid malignancies (MIP1α, blk, TR3, mtmr6). Taken together, our data define new molecular markers specific to resistant B-CLL subsets that might be of clinical relevance.

B-cell chronic lymphoid leukemia (BCLL) is a highly heterogeneous human malignancy, presumably reflecting specific molecular alterations in gene expression and protein activity that are thought to underlie the variable disease outcome. Most B-CLL cell samples undergo apoptotic death in response to DNA damage. However, a clinically distinct aggressive subset of B-CLL is completely resistant in vitro to irradiation-induced apoptosis. We therefore addressed 2 series of microarray analyses on 4 sensitive and 3 resistant B-CLL cell samples and compared their gene expression patterns before and after apoptotic stimuli. Data analysis pointed out 16 genes whose expression varied at least 2-fold specifically in resistant cells. We validated these selected genes by real-time quantitative reverse transcription–polymerase chain reaction (RT-PCR) on 7 microarray samples and confirmed their altered expression level on 15 additional B-CLL cell samples not included in the microarray analysis. In this manner, in 11 sensitive and 11 resistant B-CLL cell samples tested, 13 genes were found to be specific for all resistant samples: nuclear orphan receptor TR3, major histocompatibility complex (MHC) class II glycoprotein HLA-DQA1, mtmr6, c-myc, c-rel, c-IAP1, mat2A, and fmod were up-regulated, whereas MIP1a/GOS19-1 homolog, stat1, blk, hsp27, and ech1 were down-regulated. In some cases, the expression profile may be dependent on the status of p53. Some of these genes encode general apoptotic factors but also exhibit lymphoid cell specificities that could potentially be linked to the development of lymphoid malignancies (MIP1α, blk, TR3, mtmr6). Taken together, our data define new molecular markers specific to resistant B-CLL subsets that might be of clinical relevance.

T-acute lymphoblastic leukemias (T-ALLs) derive from human T-lymphoid precursors arrested at various early stages of development. Correlation of phenotype and T-cell receptor (TCR) status with RAG-1 and pTα transcription in 114 T-ALLs demonstrated that they largely reflect physiologic T-lymphoid development. Half the TCRαβ lineage T-ALLs expressed a pre-TCR, as evidenced by RAG-1, pTα, and cTCRβ expression, absence of TCRδ deletion, and a sCD3−, CD1a+, CD4/8 double-positive (DP) phenotype, in keeping with a population undergoing β selection. Most TCRγδ T-ALLs were pTα, terminal deoxynucleotidyl transferase (TdT), and RAG-1lo/neg, double-negative/single-positive (DN/SP), and demonstrated only TCRβ DJ rearrangement, whereas 40% were pTα, TdT, and RAG-1 positive, DP, and demonstrated TCRβ V(D)J rearrangement, with cTCRβ expression in proportion. As such they may correspond to TCRαβ lineage precursors selected by TCRγδ expression, to early γδ cells recently derived from a pTα+common αβ/γδ precursor, or to a lineage-deregulated αβ/γδ intermediate. Approximately 30% of T-ALLs were sCD3/cTCRβ−and corresponded to nonrestricted thymic precursors because they expressed non–T-restricted markers such as CD34, CD13, CD33, and CD56 and were predominantly DN, CD1a, pTα, and RAG-1 low/negative, despite immature TCRδ and TCRγ rearrangements. TCR gene configuration identified progressive T-lymphoid restriction. T-ALLs, therefore, provide homogeneous expansions of minor human lymphoid precursor populations that can aid in the understanding of healthy human T-cell development.

T-acute lymphoblastic leukemias (T-ALLs) derive from human T-lymphoid precursors arrested at various early stages of development. Correlation of phenotype and T-cell receptor (TCR) status with RAG-1 and pTα transcription in 114 T-ALLs demonstrated that they largely reflect physiologic T-lymphoid development. Half the TCRαβ lineage T-ALLs expressed a pre-TCR, as evidenced by RAG-1, pTα, and cTCRβ expression, absence of TCRδ deletion, and a sCD3−, CD1a+, CD4/8 double-positive (DP) phenotype, in keeping with a population undergoing β selection. Most TCRγδ T-ALLs were pTα, terminal deoxynucleotidyl transferase (TdT), and RAG-1lo/neg, double-negative/single-positive (DN/SP), and demonstrated only TCRβ DJ rearrangement, whereas 40% were pTα, TdT, and RAG-1 positive, DP, and demonstrated TCRβ V(D)J rearrangement, with cTCRβ expression in proportion. As such they may correspond to TCRαβ lineage precursors selected by TCRγδ expression, to early γδ cells recently derived from a pTα+ common αβ/γδ precursor, or to a lineage-deregulated αβ/γδ intermediate. Approximately 30% of T-ALLs were sCD3/cTCRβ− and corresponded to nonrestricted thymic precursors because they expressed non–T-restricted markers such as CD34, CD13, CD33, and CD56 and were predominantly DN, CD1a, pTα, and RAG-1 low/negative, despite immature TCRδ and TCRγ rearrangements. TCR gene configuration identified progressive T-lymphoid restriction. T-ALLs, therefore, provide homogeneous expansions of minor human lymphoid precursor populations that can aid in the understanding of healthy human T-cell development.

It was recently demonstrated that classification of posttransplantation lymphoproliferative disorders (PT-LPDs) into morphological and molecular categories is clinically relevant. It was also reported that PT-LPD not associated with Epstein-Barr virus (EBV. had a more aggressive course than most lesions associated with EBV. Because the cyclin-dependent kinase inhibitor p16/INK4ahas been reported to be frequently inactivated in high-grade lymphomas, we evaluated 17 PT-LPD to determine whether p16/INK4aexpression could be correlated to morphology, EBV detection, and a Ki-67 labeling index. We demonstrated that tumors with no p16/INK4aexpression (n= 8) had a predominantly monomorphic appearance, and most were EBV negative (respectively, 7/8 and 5/8), whereas lesions with p16/INK4aexpression (n= 9) were mostly polymorphic PT-LPD (6/9) (P= 0.049) and associated with EBV (9/9) (P= 0.015). In particular, strong p16/INK4aexpression was observed in atypical immunoblasts and Reed-Sternberg-like cells. Furthermore, the proliferation index was significantly higher in tumors lacking p16/INK4aexpression than in other lesions (P= 0.0008). In conclusion, down-regulation of p16/INK4awas mostly observed in PT-LPD lesions known to follow more aggressive courses: monomorphic tumors and EBV-negative PT-neoplasms. Conversely, overexpression of p16/INK4awas associated with EBV-positive PT-LPD. While p16/INK4a might play a role in the proliferative rate of LP-LPD, further investigations are needed to assess the clinical relevance of p16/INK4aexpression in predicting the evolution of tumors and to explain how EBV could favor p16/INK4a protein accumulation in lesions.

Human herpesvirus‐8 (HHV‐8), associated with Kaposi's sarcoma, primary effusion lymphoma, and Castleman's disease, has been found in circulating B‐cells and might have a causative role in B‐cell malignancies associated with immunodeficiency syndromes. We determined the rate of detection and intratumoral virus load of HHV‐8 by means of a semiquantitative approach in post‐transplant lymphoproliferative diseases (PTLDs), AIDS‐related non‐Hodgkin's lymphomas (NHLs), including both Burkitt's lymphomas (BLs) and large cell lymphomas (LCLs), as well as in control groups consisting of follicular hyperplasias (FHs) and HIV‐negative LCLs. HHV‐8 sequences were detected at a similar rate in HIV‐negative PTLDs (24%), HIV‐negative LCLs (22%) and HIV‐negative FHs (17%). The detection rate was significantly higher in HIV‐positive BLs (73%), HIV‐positive LCLs (67%), and HIV‐positive FHs (65%) supporting the view of an epidemiological link between HHV‐8 and HIV infections. The viral load was 102genome copies per cell in the single case of primary effusion lymphoma included in the LCL group while it was 10−3copy per cell (median value; range: 10−4–10−1) in all the other HHV‐8‐positive samples. No significant difference of viral load was found according to HIV status. The virus loads of PTLDs and HIV‐positive LCLs were significantly higher than those observed in HIV‐positive BLs and FHs, suggesting, to some extent, that the degree of immunodeficiency may influence HHV‐8 replication. However, with the exception of the single case of primary effusion lymphoma studied, the low intratumoral load of HHV‐8 strongly argues against a direct causative agent of the virus in the occurrence of PTLDs and AIDS‐related NHLs. J. Med. Virol. 53:277–281, 1997.© 1997 Wiley‐Liss, Inc.

To characterize early B-cell precursors in humans, we correlated immunoglobulin heavy chain (IgH) gene rearrangement status with the CD34, CD19, and CD10 cell surface markers. Highly purified adult bone marrow (BM) cell fractions were obtained by two successive rounds of flow cytometric cell sorting, and IgH rearrangements were analyzed by polymerase chain reaction (PCR) amplification. Complete VDJH rearrangements were observed in the CD34+ CD19+ fraction, but not in the more immature CD34+ CD19− fraction. About one quarter of these rearrangements had an open reading frame, thus potentially permitting the synthesis of a μ chain. Partial DJH rearrangements were detected in both CD34+ CD19+ and CD34+ CD19− subsets, although they were less abundant in the latter. When triple labeling was used to better characterize the CD34+ CD19− population, DJH rearrangements were found to be present in the CD34+ CD10+ CD19− fraction, but not in the more primitive CD34+ CD10− CD19−. These results indicate that IgH gene rearrangements occur in CD34+ BM cells and that they initiate in immature progenitors expressing the CD10, but not yet the CD19 surface antigen. Finally, the presence of IgH gene rearrangements in CD34+ BM cells provides a useful marker of clonality to evaluate the possible involvement of these cells in various B-cell lymphoid malignancies.

To investigate the role of polyclonal stimulation and antigen driven selection in the pathogenesis of acquired immunodeficiency syndrome (AIDS) related lymphomas, we studied the variable region nucleotide sequence of heavy (VH) and light (VL) chains expressed by 3 Burkitt lymphomas (BL) associated with HIV infection. Two cases expressed the VH3-30P1 gene with 88.6% and 86.7% homology when compared to their germinal counterpart, whereas the VH4-18 was rearranged in the third one (89% identity). All these genes displayed high numbers of mutations (27, 22, 28 respectively), predominating in CDR regions. The encoded light chain genes determined for cases 1 and 2 expressed the same VκI-018 gene. These results indicate that: 1) Although, it is difficult to address the issue of VH usage based on the limited number of cases studied, Burkitt's lymphoma associated with AIDS may use a restricted repertoire of Ig genes. 2) Mutations and/or replacements predominated in CDR regions, which might suggest the occurence of an antigen driven selection process, at least in some AIDS associated lymphomas. However, the high ratio of mutations observed in framework (FW) regions also favors the possibility that the antigen selection process is associated with polyclonal B cell stimulation.

To characterize early B-cell precursors in humans, we correlated immunoglobulin heavy chain (IgH) gene rearrangement status with the CD34, CD19, and CD10 cell surface markers. Highly purified adult bone marrow (BM) cell fractions were obtained by two successive rounds of flow cytometric cell sorting, and IgH rearrangements were analyzed by polymerase chain reaction (PCR) amplification. Complete VDJHrearrangements were observed in the CD34+CD19+fraction, but not in the more immature CD34+CD19−fraction. About one quarter of these rearrangements had an open reading frame, thus potentially permitting the synthesis of a μ chain. Partial DJHrearrangements were detected in both CD34+CD19+and CD34+CD19−subsets, although they were less abundant in the latter. When triple labeling was used to better characterize the CD34+CD19−population, DJHrearrangements were found to be present in the CD34+CD10+CD19−fraction, but not in the more primitive CD34+CD10−CD19−. These results indicate that IgH gene rearrangements occur in CD34+BM cells and that they initiate in immature progenitors expressing the CD10, but not yet the CD19 surface antigen. Finally, the presence of IgH gene rearrangements in CD34+BM cells provides a useful marker of clonality to evaluate the possible involvement of these cells in various B-cell lymphoid malignancies.

Recent developments in the management of chronic lymphocytic leukemia (CLL) patients have made necessary the availability of dependable prognostic factors. We have developed a prognostic index derived from the multivariate analysis of 339 stage A patients at diagnosis, exhaustively studied for classical and recent predictive markers. Only 4 biologic parameters were found to be independent predictors of progression-free survival (PFS): serum thymidine kinase (sTK), lymphocytosis, β2-microglobulin, and CD38 expression. Two groups were distinguishable: cases with no or 1 risk factor (among whom 85% did not progress after 7 years), and cases with 2 or more factors showing a median PFS of 20 months. Finally, we propose an easy, fast, cost-effective strategy for a trustworthy prognostication in stage A patients, who currently represent more than 80% of the CLL population, allowing physicians to adapt follow-up individually.

Recent developments in the management of chronic lymphocytic leukemia (CLL) patients have made necessary the availability of dependable prognostic factors. We have developed a prognostic index derived from the multivariate analysis of 339 stage A patients at diagnosis, exhaustively studied for classical and recent predictive markers. Only 4 biologic parameters were found to be independent predictors of progression-free survival (PFS): serum thymidine kinase (sTK), lymphocytosis, β2-microglobulin, and CD38 expression. Two groups were distinguishable: cases with no or 1 risk factor (among whom 85% did not progress after 7 years), and cases with 2 or more factors showing a median PFS of 20 months. Finally, we propose an easy, fast, cost-effective strategy for a trustworthy prognostication in stage A patients, who currently represent more than 80% of the CLL population, allowing physicians to adapt follow-up individually.

• Two patients presented with a large tumoral nasopharyngeal lesion with obstructive symptoms, which suggested a malignant tumor. They were black men of Caribbean origin who were infected with human immunodeficiency virus 1. In both cases, histologic examination revealed intense but benign lymphoid follicular hyperplasia, and immunohistochemical studies were consistent with its polyclonal nature. DNA studies performed on tumoral tissue failed to disclose immunoglobulin or T-cell receptor gene rearrangements. In one biopsy specimen, DNA hybridization using Epstein-Barr virus—specific probes showed no evidence of Epstein-Barr virus-DNA sequences. The nasopharynx can be involved in the diffuse extranodal lymphoid hyperplasia associated with human immunodeficiency virus infection.(Arch Intern Med. 1989;149:2359-2361)

From 1994 to 2000, 984 adults aged from 15 to 55 years with newly diagnosed Acute Lymphoblastic Leukemia (ALL) were eligible for randomization in the multicentric LALA-94 clinical protocol. The t(9;22), t(1;19) and t(4;11) translocations corresponding to BCR-ABL, E2A-PBX1 and MLL-AF4 fusion gene transcripts respectively, were considered as independent poor prognostic factors. Standardized RT-PCR analysis of these fusion gene transcripts were performed by 17 laboratories in order to provide data before the second randomization (J35) on 787 patients. In this multicentric study, validated data were available for therapeutic stratification for 91% of these analysed patients. No false positive RT-PCR was reported. Secondarily to retrospective BCR-ABL FISH, few false BCR-ABL negative RT-PCR were identified, leading to the design of new BIOMED-1 primers for b3-a3 junctions detection. Moreover, the LALA-94 study allowed to define new guidelines for molecular analysis at diagnosis. Like in other studies, the BCR-ABL transcript was found to be the most frequent molecular abnormality in B-ALL (24%) whereas MLL-AF4 and E2A-PBX1 were detected in 5% and 3.5% of B-ALL, respectively. Epidemiological and clinical data of MLL-AF4 and E2A-PBX1 were concordant with previous publications. Interestingly, because of the large number of reviewed patients, the different BCR-ABL subtypes (M-BCR and m-BCR) were statistically characterized by few clinical data. M-BCR subgroups had a higher age than m-BCR (p= 0.016) and occurs especially during the second semester (p= 0.034). Moreover, the comparison of clinical data at diagnosis of M-BCR variants showed that median age of b3a2 was statistically younger than b2a2 (p= 0.04) and that b3a2 occurs more frequently in man (p= 0.02). For the first time, these data suggest that these BCR-ABL breakpoints: m-BCR and M-BCR and also b2a2 and b2a3, are secondary to different physio-oncologic mechanisms even if therapeutic regimens including the same targeted therapy (tyrosine kinase inhibitor) for all BCR-ABL variants is the rule today.

Insertions/duplications and deletions (I/D/Ds) in IG variable region genes are infrequent sequelae of the somatic hypermutation process. In the present study, we document the occurrence of nucleotide I/D/Ds in rearranged IGHV genes in CLL patients. Among 809 IGHV-D-J sequences amplified in 760 CLL cases, 9 (1.11%) and 15 (1.85%) sequences exhibited IGHV sequence changes consistent with nucleotide insertions/duplications or deletions, respectively. I/D/Ds were found in genes of the IGHV1, IGHV3 and IGHV4 subgroups, always within mutated IGHV-D-J rearrangements. In 21/24 cases, the inserted/duplicated or lost nucleotides occurred in multiples of 3; therefore, the original reading frame was maintained and a potentially intact receptor was coded. I/D/Ds were located completely or in part within CDRs in 21/24 cases; sequence motifs (AGY, AGA, AAC trinucleotides) that resemble intrinsic hotspots for somatic hypermutation were identified in 21/24 sequences. Short stretches with high homology (misalignment feet) that would offer the DNA polymerase an alternative template for re-annealing in cases of replication slippage were identified in all CLL sequences carrying I/D/Ds. I/D/Ds were generated somatically since (i) they always occurred in cases with somatic mutations, (ii) they could not be found on sequencing analysis of the corresponding germline IGHV genes amplified on DNA isolated from selected patients’ neutrophils, thus excluding a possible genetic polymorphism. The incidence of I/D/Ds in CLL is consistent with previous reports in normal, autoreactive and neoplastic human B cells, thus seemingly indicating that these modifications generally arise without any particular disease-specific associations. A striking exception to this rule was identified in the case of CLL IGHV3-21 expressing cases: one aminoacid was deleted from the CDR2 region in 16/74 (21.6%) IGHV3-21 CLL sequences (database-derived IGHV3-21 CLL cases + present series) vs. only 2/340 (0.59%) non-CLL IGHV3-21 sequences; 15/16 CLL IGHV3-21 sequences carrying this deletion belonged to a subset with unique, shared HCDR3s and light chain CDR3 motifs. The effect of the CDR2 deletion on the structure of the IG molecules in this subset of CLL patients was studied with molecular modelling and dynamics simulations. The models suggested that the deletion could be accommodated without significantly affecting the local structure. The close association of deletions in CDR2 with the homologous subset of IGHV3-21 expressing CLL cases provides further evidence for the importance of an antigenic drive in malignant transformation and/or maintenance of the neoplastic clone in at least some CLL cases.