ACOX1-mediated peroxisomal fatty acid oxidation contributes to metabolic reprogramming and survival in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is still an incurable disease, with many patients developing resistance to conventional and targeted therapies. To better understand the physiology of CLL and facilitate the development of innovative treatment options, we examined specific metabolic features in the tumor CLL B-lymphocytes. We observed metabolic reprogramming, characterized by a high level of mitochondrial oxidative phosphorylation activity, a low glycolytic rate, and the presence of C2- to C6-carnitine end-products revealing an unexpected, essential role for peroxisomal fatty acid beta-oxidation (pFAO). Accordingly, downmodulation of ACOX1 (a rate-limiting pFAO enzyme overexpressed in CLL cells) was enough to shift the CLL cells' metabolism from lipids to a carbon- and amino-acid-based phenotype. Complete blockade of ACOX1 resulted in lipid droplet accumulation and caspase-dependent death in CLL cells, including those from individuals with poor cytogenetic and clinical prognostic factors. In a therapeutic translational approach, ACOX1 inhibition spared non-tumor blood cells from CLL patients but led to the death of circulating, BCR-stimulated CLL B-lymphocytes and CLL B-cells receiving pro-survival stromal signals. Furthermore, a combination of ACOX1 and BTK inhibitors had a synergistic killing effect. Overall, our results highlight a less-studied but essential metabolic pathway in CLL and pave the way towards the development of new, metabolism-based treatment options.

The Value of Neutrophil Gelatinase-Associated Lipocalin Receptor as a Novel Partner of CD38 in Chronic Lymphocytic Leukemia: From an Adverse Prognostic Factor to a Potential Pharmacological Target?

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of neoplastic B lymphocytes that escape death, and correlates with the expression of negative prognostic markers such as the CD38 antigen. Although certain new drugs approved by the US Food and Drug Administration improve the clinical outcome of CLL patients, drug resistance and disease relapse still occur. Like CD38, neutrophil gelatinase-associated lipocalin receptor (NGAL-R) is frequently overexpressed in CLL cells. Here, we evaluated the concomitant surface expression of NGAL-R and CD38 in leukemic blood cells from 52 CLL patients (37 untreated, 8 in clinical remission, and 7 relapsed). We provide evidence of a positive correlation between NGAL-R and CD38 levels both in the interpatient cohorts (p < 0.0001) and in individual patients, indicating a constitutive association of NGAL-R and CD38 at the cell level. Patients with progressing CLL showed a time-dependent increase in NGAL-R/CD38 levels. In treated CLL patients who achieved clinical remission, NGAL-R/CD38 levels were decreased, and were significantly lower than in the untreated and relapsed groups (p < 0.02). As NGAL-R and CD38 participate in CLL cell survival, envisioning their simultaneous inhibition with bispecific NGAL-R/CD38 antibodies capable of inducing leukemic cell death might provide therapeutic benefit for CLL patients.

Combining MYD88 L265P mutation detection and clonality determination on CSF cellular and cell-free DNA improves diagnosis of primary CNS lymphoma

Diagnosis of primary central nervous system lymphoma (PCNSL) is challenging, and although brain biopsy remains the gold standard, cerebrospinal fluid (CSF) constitutes a less invasive source of lymphomatous biomarkers. In a retrospective cohort of 54 PCNSL cases tested at diagnosis or relapse, we evaluated the contribution of immunoglobulin heavy chain (IGH) gene clonality and MYD88 L265P detection on both CSF cell pellets and supernatants, in comparison with cytology, flow cytometry, interleukin (IL)-10 and IL-6 quantification. Clonality assessment included a new assay to detect partial IGH-DJ rearrangements. Clonal IGH rearrangements and/or MYD88 L265P mutation were detected in 27 (50%) cell pellets and 24 (44%) supernatant cell-free (cf) DNA. Combining analyses on both compartments, 36 (66%) cases had at least one detectable molecular marker, present only in cfDNA for 9 (16%) of them. While cytology and flow cytometry were positive in only 7 (13.0%) and 9 (17.3%) cases respectively, high IL-10 levels were observed in 36 (66.7%) cases. Overall, taking into account molecular and cytokine results, 46/54 (85%) cases had at least one lymphomatous biomarker detectable in the CSF. These results show that this combination of biomarkers evaluated on both cell pellet and supernatant CSF fractions improves significantly the biological diagnosis of PCNSL.

Perls’ Stain Guidelines from the French-Speaking Cellular Hematology Group (GFHC)

In order to standardize cellular hematology practices, the French-speaking Cellular Hematology Group (Groupe Francophone d’Hématologie Cellulaire, GFHC) focused on Perls’ stain. A national survey was carried out, leading to the proposal of recommendations on insoluble iron detection and quantification in bone marrow. The criteria presented here met with a “strong professional agreement” and follow the suggestions of the World Health Organization’s classification of hematological malignancies.

Primary vitreoretinal lymphoma: short review of the literature, results of a European survey and French guidelines of the LOC network for diagnosis, treatment and follow-up

PURPOSE OF REVIEW

The aim of this study was to highlight the diagnostic and management challenges of primary vitreoretinal lymphoma (PVRL) through a review of the literature and a European survey on real-life practices for PVRL.

RECENT FINDINGS

The care of PVRL patients is heterogeneous between specialists and countries. Upfront systemic treatment based on high-dose methotrexate chemotherapy, with or without local treatment, might reduce or delay the risk of brain relapse.Ibrutinib, lenalidomide with or without rituximab, and temozolomide are effective for patients with relapsed/refractory PVRL and should be tested as first-line treatments.

SUMMARY

The prognosis of PVRL remains dismal. No firm conclusion regarding optimal treatment can yet be drawn. The risk of brain relapse remains high. Diagnostic procedures and assessment of therapeutic responses need to be homogenized. Collaboration between specialists involved in PVRL and multicentric prospective therapeutic studies are strongly needed. The recommendations of the French group for primary oculocerebral lymphoma (LOC network) are provided, as a basis for further European collaborative work.

Clinical and biological features of B-cell neoplasms with CDK6 translocations: an association with a subgroup of splenic marginal zone lymphomas displaying frequent CD5 expression, prolymphocytic cells, and TP53 abnormalities

A translocation involving the cyclin-dependent kinase 6 (CDK6) gene [t(CDK6)] is a rare but recurrent abnormality in B-cell neoplasms. To further characterise this aberration, we studied 57 cases; the largest series reported to date. Fluorescence in situ hybridisation analysis confirmed the involvement of CDK6 in all cases, including t(2;7)(p11;q21) immunoglobulin kappa locus (IGK)/CDK6 (n = 51), t(7;14)(q21;q32) CDK6/immunoglobulin heavy locus (IGH) (n = 2) and the previously undescribed t(7;14)(q21;q11) CDK6/T-cell receptor alpha locus (TRA)/T-cell receptor delta locus (TRD) (n = 4). In total, 10 patients were diagnosed with chronic lymphocytic leukaemia, monoclonal B-cell lymphocytosis or small lymphocytic lymphoma, and 47 had small B-cell lymphoma (SmBL) including 36 cases of marginal zone lymphoma (MZL; 34 splenic MZLs, one nodal MZL and one bronchus-associated lymphoid tissue lymphoma). In all, 18 of the 26 cytologically reviewed cases of MZL (69%) had an atypical aspect with prolymphocytic cells. Among the 47 patients with MZL/SmBL, CD5 expression was found in 26 (55%) and the tumour protein p53 (TP53) deletion in 22 (47%). The TP53 gene was mutated in 10/30 (33%); the 7q deletion was detected in only one case, and no Notch receptor 2 (NOTCH2) mutations were found. Immunoglobulin heavy-chain variable-region (IGHV) locus sequencing revealed that none harboured an IGHV1-02*04 gene. Overall survival was 82% at 10 years and not influenced by TP53 aberration. Our present findings suggest that most t(CDK6)+ neoplasms correspond to a particular subgroup of indolent marginal zone B-cell lymphomas with distinctive features.

Gain of the short arm of chromosome 2 (2p gain) has a significant role in drug-resistant chronic lymphocytic leukemia

The different types of drug resistance encountered in chronic lymphocytic leukemia (CLL) cannot be fully accounted for by the 17p deletion (and/or TP53 mutation), a complex karyotype (CK), immunoglobulin heavy‐chain variable region genes (IGHV) status and gene mutations. Hence, we sought to assess the associations between recurrent genomic abnormalities in CLL and the disease's development and outcome. To this end, we analyzed 64 samples from patients with CLL and gain of the short arm of chromosome 2 (2p+), which is frequent in late‐stage and relapsed/refractory CLL. We found that fludarabine/cyclophosphamide/rituximab (a common first‐line treatment in CLL) is not effective in removing the 2p+ clone ‐ even in samples lacking a CK, the 17p deletion or unmutated IGHV. Our results suggest strongly that patients with CLL should be screened for 2p+ (using karyotyping and fluorescence in situ hybridization) before a treatment option is chosen. Longer follow‐up is now required to evaluate bendamustine‐rituximab, ibrutinib, and idelalisib‐rituximab treatments.

Non syndromic childhood onset congenital sideroblastic anemia: A report of 13 patients identified with an ALAS2 or SLC25A38 mutation

The most frequent germline mutations responsible for non syndromic congenital sideroblastic anemia are identified in ALAS2 and SLC25A38 genes. Iron overload is a key issue and optimal chelation therapy should be used to limit its adverse effects on the development of children. Our multicentre retrospective descriptive study compared the strategies for diagnosis and management of congenital sideroblastic anemia during the follow-up of six patients with an ALAS2 mutation and seven patients with an SLC25A38 mutation. We described in depth the clinical, biological and radiological phenotype of these patients at diagnosis and during follow-up and highlighted our results with a review of available evidence and data on the management strategies for congenital sideroblastic anemia. This report confirms the considerable variability in manifestations among patients with ALAS2 or SLC25A38 mutations and draws attention to differences in the assessment and the monitoring of iron overload and its complications. The use of an international registry would certainly help defining recommendations for the management of these rare disorders to improve patient outcome.

Cerebrospinal fluid interleukin (IL)-10 and IL-10:IL-6 ratio as biomarkers for small B-cell lymphoproliferations with leptomeningeal dissemination

We here report for the first time that low levels of interleukin (IL)-10 do not exclude lymphomatous meningitis (LM) in B-cell lymphoproliferative disorders (CLPD). Unexpectedly, IL-10 levels and IL-10:IL-6 ratio in CLPD differed from the levels observed in diffuse large B-cell lymphoma (DLBCL). We report the usefulness of adding the IL-10:IL-6 ratio in order to potentially reveal more aggressive lymphomas: either a transformation or an association with another "hidden" lymphoma such as primary CNS lymphoma (PCNSL).

A new phosphorylated form of Ku70 identified in resistant leukemic cells confers fast but unfaithful DNA repair in cancer cell lines

Ku70-dependent canonical nonhomologous end-joining (c-NHEJ) DNA repair system is fundamental to the genome maintenance and B-cell lineage. c-NHEJ is upregulated and error-prone in incurable forms of chronic lymphocytic leukemia which also displays telomere dysfunction, multiple chromosomal aberrations and the resistance to DNA damage-induced apoptosis. We identify in these cells a novel DNA damage inducible form of phospho-Ku70. In vitro in different cancer cell lines, Ku70 phosphorylation occurs in a heterodimer Ku70/Ku80 complex within minutes of genotoxic stress, necessitating its interaction with DNA damage-induced kinase pS2056-DNA-PKcs and/or pS1981-ATM. The mutagenic effects of phospho-Ku70 are documented by a defective S/G2 checkpoint, accelerated disappearance of γ-H2AX foci and kinetics of DNA repair resulting in an increased level of genotoxic stress-induced chromosomal aberrations. Together, these data unveil an involvement of phospho-Ku70 in fast but inaccurate DNA repair; a new paradigm linked to both the deregulation of c-NHEJ and the resistance of malignant cells.

Renal thrombotic microangiopathy and FIP1L1/PDGFRα-associated myeloproliferative variant of hypereosinophilic syndrome

We report a case of renal thrombotic microangiopathy (TMA) in a myeloproliferative variant of hypereosinophilic syndrome (HES) in a 24-year-old man which resolved with imatinib therapy. This is one of a few cases in the literature to date describing TMA in HES, suggesting that the pathogenesis of thrombosis is at least in part related to damage from activated eosinophils.

Lenalidomide with or without erythropoietin in transfusion-dependent erythropoiesis-stimulating agent-refractory lower-risk MDS without 5q deletion

After failure of erythropoiesis-stimulating agents (ESAs), lenalidomide (LEN) yields red blood cell (RBC) transfusion independence (TI) in 20-30% of lower-risk non-del5q myelodysplastic syndrome (MDS). Several observations suggest an additive effect of ESA and LEN in this situation. We performed a randomized phase III study in 131 RBC transfusion-dependent (TD, median transfusion requirement six RBC units per 8 weeks) lower-risk ESA-refractory non-del5q MDS. Patients received LEN alone, 10 mg per day, 21 days per 4 weeks (L arm) or LEN (same schedule) + erythropoietin (EPO) beta, 60,000 U per week (LE arm). In an intent-to-treat (ITT) analysis, erythroid response (HI-E, IWG 2006 criteria) after four treatment cycles (primary end point) was 23.1% (95% CI 13.5-35.2) in the L arm and 39.4% (95% CI 27.6-52.2) in the LE arm (P=0.044), while RBC-TI was reached in 13.8 and 24.2% of the patients in the L and LE arms, respectively (P=0.13). Median response duration was 18.1 and 15.1 months in the L and LE arms, respectively (P=0.47). Side effects were moderate and similar in the two arms. Low baseline serum EPO level and a G polymorphism of CRBN gene predicted HI-E. Combining LEN and EPO significantly improves erythroid response over LEN alone in lower-risk non-del5q MDS patients with anemia resistant to ESA.

14q deletions are associated with trisomy 12, NOTCH1 mutations and unmutated IGHV genes in chronic lymphocytic leukemia and small lymphocytic lymphoma

Deletions of the long arm of chromosome 14 [del(14q)] are rare but recurrently observed in mature B-cell neoplasms, particularly in chronic lymphocytic leukemia (CLL). To further characterize this aberration, we studied 81 cases with del(14q): 54 of CLL and 27 of small lymphocytic lymphoma (SLL), the largest reported series to date. Using karyotype and fluorescence in situ hybridization (FISH), the most frequent additional abnormality was trisomy 12 (tri12), observed in 28/79 (35%) cases, followed by del13q14 (12/79, 15%), delTP53 (11/80, 14%) delATM (5/79, 6%), and del6q21 (3/76, 4%). IGHV genes were unmutated in 41/53 (77%) patients, with a high frequency of IGHV1-69 (21/52, 40%). NOTCH1 gene was mutated in 14/45 (31%) patients. There was no significant difference in cytogenetic and molecular abnormalities between CLL and SLL. Investigations using FISH and SNP-array demonstrated the heterogeneous size of the 14q deletions. However, a group with the same del(14)(q24.1q32.33) was identified in 48% of cases. In this group, tri12 (P = 0.004) and NOTCH1 mutations (P = 0.02) were significantly more frequent than in the other patients. In CLL patients with del(14q), median treatment-free survival (TFS) was 27 months. In conclusion, del(14q) is associated with tri12 and with pejorative prognostic factors: unmutated IGHV genes (with over-representation of the IGHV1-69 repertoire), NOTCH1 mutations, and a short TFS.

Sex chromosome loss may represent a disease-associated clonal population in chronic lymphocytic leukemia

Whether sex chromosome loss (SCL) is an age-related phenomenon or a cytogenetic marker of hematological disease is unclear. To address this issue in chronic lymphocytic leukemia (CLL), we investigated 20 cases with X or Y chromosome loss detected by conventional cytogenetics (CC). The frequency of SCL was low in CLL (2.3%). It was the sole abnormality, as detected by CC, in 10/20 (50%) patients. Fluorescence in situ hybridization (FISH) analyses confirmed SCL in all patients tested, present in 5-88% of cells (median: 68%). Deletions of 13q were observed by FISH in 16/20 (80%) patients. Compared with CLL without SCL, SCL was significantly associated with 13q deletion, especially when bi-allelic (P = 0.04). Co-hybridization analyses showed that SCL could be a concomitant, primary or secondary change, or be present in an independent clone. FISH analyses were performed on blood sub-populations isolated by Ficoll or flow cytometry. Comparing mononuclear cells (including CLL cells) and polynuclear cells separated by Ficoll, a maximum of 2% of polynuclear cells were found with SCL, whereas mononuclear cells exhibited a significantly higher loss frequency (range: 6-87%) (P = 0.03). Comparing B-cells (including CLL cells) and T-cells sorted by flow cytometry, the proportion of B-CD19+ cells with SCL was significantly higher (range: 88-96%) than that observed in T-CD3+ cells (range: 2-6%) (P = 0.008). We conclude that SCL has to be considered as a clonal aberration in CLL that may participate in the oncogenic process.

Specific chromosomal IG translocations have different prognoses in chronic lymphocytic leukemia

BACKGROUND

Chromosomal translocations are usually analyzed as a single entity, and are associated with a poor outcome in chronic lymphocytic leukemia. Translocations involving immunoglobulin genes are recurrent, but uncommon (<5%), and their individual prognosis is not clear. The two most frequent partners are BCL2 (18q21) and BCL3 (19q13).

DESIGNS AND METHODS

Herein, 75 cases are reported of chronic lymphocytic leukemia and t(14;18) (BCL2-CLLs). Our series benefits from morphological, immunological and cytogenetical reviews. The IGHV status analyses were performed by referring laboratories. Comparison was made with our previously published series of chronic lymphocytic leukemia patients with t(14;19) (BCL3-CLLs, n=29).

RESULTS

Compared with BCL3-CLLs, lymphocytosis was lower in BCL2-CLLs (p<0.008), and splenomegaly was less frequent (p<0.0001). There were more "typical" morphologies (p<0.005) and Matutes scores >4 (p<0.001) in the BCL2-CLLs group, and less CD38 expression (p<0.04). More variant BCL2-translocations were observed (t(18;22), n=11; 2t(2;18), n=2; p<0.02), and BCL2-translocation was frequently single (p<0.002). Complex karyotypes (p<0.02), trisomy 12 (p<0.03), 6q deletion (p<0.002) and TP53 deletion (p<0.02) were less frequent in BCL2-CLLs, whereas 13q deletion was more frequent (p<0.005). The IGHV gene was frequently mutated in BCL2-CLLs (p<0.0001). Treatment-free survival was longer in BCL2-CLLs (p<0.0001).

CONCLUSIONS

BCL2-CLL.S express CD5 and lack expression of CD38, and have a Matutes score ≥4, frequent trisomy 12, no ATM and 6q deletions, and a mutated IGHV status. Compared to BCL3-CLLs, BCL2-CLLs are much less aggressive; indicating that identifying individual translocations and cytogenetic partners would allow improved patient stratification.

Missense SLC25A38 variations play an important role in autosomal recessive inherited sideroblastic anemia

BACKGROUND

Congenital sideroblastic anemias are rare disorders with several genetic causes; they are characterized by erythroblast mitochondrial iron overload, differ greatly in severity and some occur within a syndrome. The most common cause of non-syndromic, microcytic sideroblastic anemia is a defect in the X-linked 5-aminolevulinate synthase 2 gene but this is not always present. Recently, variations in the gene for the mitochondrial carrier SLC25A38 were reported to cause a non-syndromic, severe type of autosomal-recessive sideroblastic anemia. Further evaluation of the importance of this gene was required to estimate the proportion of patients affected and to gain further insight into the range and types of variations involved.

DESIGN AND METHODS

In three European diagnostic laboratories sequence analysis of SLC25A38 was performed on DNA from patients affected by congenital sideroblastic anemia of a non-syndromic nature not caused by variations in the 5-aminolevulinate synthase 2 gene.

RESULTS

Eleven patients whose ancestral origins spread across several continents were homozygous or compound heterozygous for ten different SLC25A38 variations causing premature termination of translation (p.Arg117X, p.Tyr109LeufsX43), predicted splicing alteration (c.625G>C; p.Asp209His) or missense substitution (p.Gln56Lys, p.Arg134Cys, p.Ile147Asn, p.Arg187Gln, p.Pro190Arg, p.Gly228Val, p.Arg278Gly). Only three of these variations have been described previously (p.Arg117X, p.Tyr109LeufsX43 and p.Asp209His). All new variants reported here are missense and affect conserved amino acids. Structure modeling suggests that these variants may influence different aspects of transport as described for mutations in other mitochondrial carrier disorders.

CONCLUSIONS

Mutations in the SLC25A38 gene cause severe, non-syndromic, microcytic/hypochromic sideroblastic anemia in many populations. Missense mutations are shown to be of importance as are mutations that affect protein production. Further investigation of these mutations should shed light on structure-function relationships in this protein.

High efficacy with five days schedule of oral fludarabine phosphate and cyclophosphamide in patients with previously untreated chronic lymphocytic leukaemia

A multicentre single-arm study testing the efficacy and toxicity of the oral combination of fludarabine and cyclophosphamide (FC) over 5 d in 75 patients with untreated B cell-chronic lymphocytic leukaemia. Oral FC demonstrated high efficacy with overall (OR) and complete response (CR) rates of 80% and 53%, respectively. Out of the 30 CR patients studied for Minimal Residual Disease (MRD) using 4-colour flow-cytometry and the 22 using Clonospecific polymerase chain reaction, 22 (66%) and 16 (68%), respectively, were MRD negative. Median survival and median treatment-free interval had not been reached at 7 years of follow-up. Median progression-free survival (PFS) was 5 years. Toxicity was acceptable, with 52% and 16% of National Cancer Institute grade 3/4 neutropenia and infections, respectively. Gastrointestinal toxicity was mild. Oral FC demonstrated a high efficacy and an acceptable safety profile and may be considered as the standard first line treatment in chronic lymphocytic leukaemia.

Evidence for MPL W515L/K mutations in hematopoietic stem cells in primitive myelofibrosis

The MPL (W515L and W515K) mutations have been detected in granulocytes of patients suffering from certain types of primitive myelofibrosis (PMF). It is still unknown whether this molecular event is also present in lymphoid cells and therefore potentially at the hematopoietic stem cell (HSC) level. Toward this goal, we conducted MPL genotyping of mature myeloid and lymphoid cells and of lymphoid/myeloid progenitors isolated from PMF patients carrying the W515 mutations. We detected both MPL mutations in granulocytes, monocytes, and platelets as well as natural killer (NK) cells but not in T cells. B/NK/myeloid and/or NK/myeloid CD34(+)CD38(-)-derived clones were found to carry the mutations. Long-term reconstitution of MPL W515 CD34(+) cells in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice was successful for as long as 12 weeks after transplantation, indicating that MPL W515 mutations were present in HSCs. Moreover, the 2 MPL mutations induced a spontaneous megakaryocytic growth in culture with an overall normal response to thrombopoietin (TPO). In contrast, erythroid progenitors remained EPO dependent. These results demonstrate that in PMF, the MPL W515L or K mutation induces a spontaneous megakaryocyte (MK) differentiation and occurs in a multipotent HSCs.

Enumeration of nucleated red blood cells with the ADVIA 2120 Hematology System: an International Multicenter Clinical Trial

The accurate, reproducible, and timely reporting of nucleated red blood cells (NRBC) is an important function of the clinical hematology laboratory. We used 960 samples from 5 worldwide sites to evaluate a new NRBC enumeration method for the ADVIA 2120 Hematology System. The method showed excellent correlation with microscopy (r = 0.93). Sensitivity and specificity for the presence of NRBC for all samples analyzed was 77.3% and 74.6%, respectively. Almost all false negative samples were at NRBC counts <or=10/100 white blood cells (WBC). All false negative samples and the vast majority of the false positive specimens would be identified in clinical practice by routine slide review of flagged results, using existing review criteria. The coefficient of variation of the method was <10% for NRBC counts >10/100 WBC. The NRBC method automatically corrects WBC counts and differential results for the presence of NRBC; the uncorrected counts are available to the user on the run screen. This method allows the enumeration of NRBC with the ADVIA 2120 Hematology System in CBC/DIFF sample mode without need for additional hardware, sample preparation, or reagents.

A comparison of the sensitivity of flow cytometry and bone marrow biopsy in the detection of minimal residual disease in chronic lymphocytic leukemia

We compared the sensitivity of bone marrow biopsy to blood flow cytometry in detecting minimal residual disease (MRD) in 29 patients with chronic lymphocytic leukemia (CLL) in clinical remission after treatment. These results demonstrate that flow cytometry is more sensitive than bone marrow biopsy in detecting MRD and in predicting relapse in CLL.

Molecular characterization of the idiopathic hypereosinophilic syndrome (HES) in 35 French patients with normal conventional cytogenetics

Idiopathic hypereosinophilic syndrome (HES) characterized by unexplained and persistent hypereosinophilia is heterogeneous and comprises several entities: a myeloproliferative form where myeloid lineages are involved with the interstitial chromosome 4q12 deletion leading to fusion between FIP1L1 and PDGFRA genes, the latter acquiring increased tyrosine kinase activity. And a lymphocytic variant, where hypereosinophilia is secondary to a primitive T lymphoid disorder demonstrated by the presence of a circulating T-cell clone. We performed molecular characterization of HES in 35 patients with normal karyotype by conventional cytogenetic analysis. TCRgamma gene rearrangements suggesting T clonality were seen in 11 (31%) patients, and FIP1L1-PDGFRA by RT-PCR in six (17%) of 35 patients, who showed no evidence of T-cell clonality. An elevated serum tryptase level was observed in FIP1L1-PDGFRA-positive patients responding to imatinib, whereas serum IL-5 levels were not elevated in T-cell associated hypereosinophilia. Sequencing FIP1L1-PDGFRA revealed scattered breakpoints in FIP1L1-exons (10-13), whereas breakpoints were restricted to exon 12 of PDGFRA. In the 29 patients without FIP1L1-PDGFRA, no activating mutation of PDGFRA/PDGFRB was detected; however; one patient responded to imatinib. FISH analysis of the 4q12 deletion was concordant with FIP1L1-PDGFRA RT-PCR data. Further investigation of the nature of FIP1L1-PDGFRA affected cells will improve the classification of HES.

Burkitt-type acute leukemia in a patient with B-prolymphocytic leukemia: evidence for a common origin

Burkitt-type acute leukemia cells were present in the bone marrow of a patient with B-prolymphocytic leukemia diagnosed from peripheral blood cell morphology. Immunophenotype analysis confirmed morphological patterns. Cytogenetic and fluorescence in situ hybridization (FISH) analysis showed an identical t(8;22)(q24;q21) with MYC locus rearrangement in blood and bone marrow cells, with additional chromosome abnormalities in the bone marrow. In addition, the loss of one copy of the TP53 gene and identical IGH DNA clonal rearrangements were shown with FISH and polymerase chain reaction analysis respectively in the two types of leukemic cells. These data indicated the common origin of the two coexisting leukemias and are the first example of such occurrence in a leukemic patient.

HHV-8-Associated T-Cell Lymphoma in a Lymph Node With Concurrent Peritoneal Effusion in an HIV-Positive Man

Primary effusion lymphoma (PEL) is an uncommon large cell lymphoma, usually seen in human immunodeficiency virus (HIV)-infected patients. PEL is characterized by various clinical, histomorphologic, and immunophenotypical features, and is associated with the human herpes virus 8 (HHV-8). PEL may present as either a body cavity-based lymphomatous effusion or a solid tumor mass. Most so-called "solid PEL" usually have an extranodal location; exceptionally rarely, they occur in lymph nodes. The majority of PEL consist of malignant cells of B-cell genotype; seldom they are of T-cell origin. We report a rare case of HHV-8-associated "solid PEL" of T-cell type in a 41-year-old HIV-seropositive man with a concomitant peritoneal effusion. The T-cell lymphoma was diagnosed on the basis of morphologic, immunophenotypic, and molecular findings of a lymph node biopsy. The tumor cells strongly expressed CD45R0, CD7, CD43, MUM1/IRF4, CD30, HHV-8, and EBER, and demonstrated a clonal rearrangement of T-cell receptor-gamma chain gene. The following case provides another example of a lymph node-based "solid" PEL, demonstrating the variety within the spectrum of HHV-8-associated lymphoma.

Impact of frontline fludarabine and cyclophosphamide combined treatment on peripheral blood stem cell mobilization in B-cell chronic lymphocytic leukemia

Ongoing studies in B-cell chronic lymphocytic leukemia are evaluating autologous peripheral blood stem cell (PBSC) transplantation in first remission following fludarabine therapy. However, fludarabine could impair PBSC harvest. In 38 patients after frontline oral fludarabine and cyclophosphamide (FDR-CY) therapy, we prospectively evaluated steady state filgrastim- or lenograstim-primed PBSC mobilization to collect 2.0 x 106/kg or more CD34 cells. The first mobilization, performed a median of 178 days (range, 69-377 days) from the last FDR-CY course, was unsuccessful in 32 patients. This result was significantly associated with a low platelet count before mobilization but not with age, interval from last FDR-CY course, initial stage, remission status, or other blood parameters. Finally, after 1, 2, and 3 mobilizations in 27, 10, and 1 patients, 2.0 x 106/kg or more CD34 cells were collected in only 12. Explorations of the mechanism of poor mobilization and adaptation of PBSC harvest policies after fludarabine treatment are therefore warranted.

Binet's staging system and VH genes are independent but complementary prognostic indicators in chronic lymphocytic leukemia

PURPOSE

Rai's and Binet's staging systems have contributed significantly to the identification of major prognostic groups in chronic lymphocytic leukemia (CLL), though they fail to accurately predict disease progression at the individual level. Biologic factors, such as the mutational status of the immunoglobulin heavy-chain variable genes (VH, cytogenetics, CD38 expression, and some serum markers, have recently improved prognostic assessment in CLL. In this study, we analyzed the prognostic value of VH mutational status within the different stages of Binet's classification in 145 patients.

PATIENTS AND METHODS

Our series consisted of 83 VH mutated (MT) and 62 VH unmutated (UM) patients. MT cases predominated within Binet's stage A (70%), whereas UM cases predominated among stages B and C (62%).

RESULTS

Median overall survival (OS) was 84 months for UM patients and was not achieved for the MT group (70% 12-year survival, P <.0001). Concerning Binet's stage A, both median OS and progression-free survival were significantly shorter for UM patients when compared with those of MT patients (97 months v not achieved, P =.0017; and 42 v 156 months, P <.0001), which compared favorably with the classical A' and A" substaging. The VH mutational profile could also segregate stage B and C patients into two groups with different survival patterns (median OS, 78 v 120 months for UM and MT patients, respectively; P =.002).

CONCLUSION

The significant survival differences observed between the VH mutational groups, among stage A and stage B and C patients, indicate that Binet's classification and VH genes are independent prognostic variables and are most likely complementary.

Idiotype-pulsed dendritic cells are able to induce antitumoral cytotoxic CD8 cells in chronic lymphocytic leukaemia

Idiotypic structures of immunoglobulins from malignant B cells constitute tumour-specific antigens, though the function of immunoglobulin-specific CD8+ T cells in disease control and rejection remains unclear. We have studied five cases of B chronic lymphocytic leukaemia patients affected with indolent (three patients) or aggressive (two patients) disease. We showed that CD8+ T cells with major histocompatibility complex class I-restricted cytotoxicity against autologous tumour B cells could be generated following repeated stimulations with idiotype-pulsed dendritic cells in vitro. CD8+ T-cell lines were able to upregulate CD69 expression and to release interferon (IFN)-gamma upon contact with the autologous B cells, though cytolytic activity was only substantiated for patients with indolent disease. The failure of cytolytic activity in patients with aggressive disease may be explained by a skewed maturation of memory CD8 cells.

Novel flow-cytometric analysis based on BCD5+ subpopulations for the evaluation of minimal residual disease in chronic lymphocytic leukaemia

We describe a new flow-cytometric analysis using quadruple labelling with anti-CD19, CD20, CD5, CD79b monoclonal antibodies and sequential gating. We determined a novel criteria defined by BCD5+CD79b-/low/total BCD5+ cells ratio (BCD5+R), and compared it with the previous definition of phenotypic remission, based on CD19+CD5+ coexpression, and with complementarity-determining region 3 polymerase chain reaction (CDR3 PCR) and clonotypic PCR (cPCR). A series of 54 peripheral blood samples from 21 chronic lymphocytic leukaemia (CLL) patients in complete haematological remission and a series of 16 from normal volunteers were analysed. In normal controls, the BCD5+R was always < 0.2. The sensitivity of the BCD5+R was 1 x 10-4vs 5 x 10-2 for CDR3 PCR and 1 x 10-5 for cPCR. Among the 54 CLL samples, 35 had a BCD5+R < 0.2 and showed polyclonal CDR3 PCR, whereas the cPCR was positive in 12 out of 20 tested. In the remaining 19 samples, BCD5+R was > 0.2, CDR3 PCR was monoclonal in 16 out of 19 and cPCR positive in 14 out 14 tested, including one out of three samples with polyclonal CDR3 amplification. Even though cPCR remains the most sensitive method to evaluate MRD, this new, sensitive and specific flow cytometric parameter, the BCD5+R, is more suitable than CDR3 PCR for routine clinical MRD assessment in CLL.

Cleaved lymphocytes in chronic lymphocytic leukemia: a detailed retrospective analysis of diagnostic features

Through a global analysis of diagnostic features, the aim was to profile CLL patients with circulating cleaved lymphocytes at diagnosis, a controversial prognostic factor. Although some of them could have been considered today as having Non-Hodgkin's lymphoma, all 106 patients of our retrospective series have had CLL treatments. Slide review distinguished seven lymphocyte morphotypes. With minimal a priori assumptions, excluding in particular clinical staging systems, forty-five diagnostic features were analyzed in 37 patients. CORICO (Correlations Iconography), a purely geometric method, deciphered the multidimensional structure of the raw data. Probabilistic monoparametric tests were made on the 106 patients. In ten patients (Binet stages: 3A, 6B, 1C), at least 8% of the lymphocytes were cleaved. Unrelated to the prolymphocytes, this morphotype had neither links with the CD5+CD23+ (9/10 vs 80/86), FMC7+ (5/10 vs 22/62), CD38 (1/7 vs 7/64) markers nor with any major CLL laboratory values; only three links characterized it: no cases of mixed marrow infiltrate (nodular: 1, interstitial: 6, diffuse: 3; ns), a lower percentage of eosinophils (ns), and predominance of CD11c (7/10 vs 20/66, p < 0.02). In conclusion, in contrast to the PLL morphotype, or to the lactic dehydrogenase (LDH) activity, which was a strong prognostic factor in this series, an independent detrimental value of the cleaved morphotype has not yet been found. Our study shows that free of modeling constraints, this method makes possible a rapid and objective insight into variable interrelations. If further explored in a prospective study, this approach may contribute to the understanding of discrepancies in the literature.

Functional monocyte-derived dendritic cells can be generated in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) remains an incurable disease. Although modern available treatments are able to induce disease regression, relapse almost inexorably occurs. Therefore, novel therapeutic strategies aimed at reducing the disease relapse rate are very much needed. Among these, the induction of tumour-associated antigen-specific cytotoxic T lymphocytes (CTL), through either DNA vaccines or injection of idiotype pulsed dendritic cells (DCs), has been actively investigated with encouraging preliminary results in B-cell malignancies. As the CLL B lymphocyte characteristically expresses low amounts of surface immunoglobulin (Ig) and T cells from these patients have been reported to display impaired functional activity, there are concerns related to the possibility of generating specific cytotoxic antitumoral T cells in this disease. In addition, no information is presently available regarding the functional ability of CLL-derived DCs. In the present work, freshly purified monocytes from CLL patients and normal donors were induced to differentiate in granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4 serum-free medium and compared for their morphological, phenotypic and functional characteristics. Our results demonstrate that: (1) functional DCs can be generated from CLL patients with similar phenotype and function to those observed from normal donors; (2) in contrast to normal control subjects, monocyte-derived DCs from CLL patients spontaneously secrete endogenous IL-10; and (3) interferon (IFN)-gamma in combination with CD40L plays a major role in priming DCs from CLL patients for IL-12 and IL-15 production. Overall, these results indicate that it is possible to derive functionally competent DCs from circulating monocytes in CLL patients.

Randomized comparison of fludarabine, CAP, and ChOP in 938 previously untreated stage B and C chronic lymphocytic leukemia patients

To comparatively assess first-line treatment with fludarabine and 2 anthracycline-containing regimens, namely CAP (cyclophosphamide, doxorubicin plus prednisone) and ChOP (cyclophosphamide, vincristine, prednisone plus doxorubicin), in advanced stages of chronic lymphocytic leukemia (CLL), previously untreated patients with stage B or C CLL were randomly allocated to receive 6 monthly courses of either ChOP, CAP, or fludarabine (FAMP), stratified based on the Binet stages. End points were overall survival, treatment response, and tolerance. From June 1, 1990 to April 15, 1998, 938 patients (651 stage B and 287 stage C) were randomized in 73 centers. Compared to ChOP and FAMP, CAP induced lower overall remission rates (58.2%; ChOP, 71.5%; FAMP; 71.1%; P <.0001 for each), including lower clinical remission rates (CAP, 15.2%; ChOP, 29.6%; FAMP, 40.1%; P =.003). By contrast, median survival time did not differ significantly according to randomization (67, 70, and 69 months in the ChOP, CAP, and FAMP groups, respectively). Incidences of infections (< 5%) and autoimmune hemolytic anemia (< 2%) during the 6 courses were similar in the randomized groups, whereas fludarabine induced, compared to ChOP and CAP, more frequent protracted thrombocytopenia (P =.003) and less frequent nausea-vomiting (P =.003) and hair loss (P <.0001). For patients with stage B and C CLL first-line fludarabine and ChOP regimens both provided similar overall survival and close response rates, and better results than CAP. However, there was an increase in clinical remission rate and a trend toward a better tolerance of fludarabine over ChOP that may influence the choice between these regimens as front-line treatments in patients with CLL.

Deregulation of the ubiquitin system and p53 proteolysis modify the apoptotic response in B-CLL lymphocytes

We recently reported increased sensitivity of B-cell chronic lymphocytic leukemia (B-CLL) lymphocytes to apoptotic death activation by the proteasome-specific inhibitor lactacystin. Here, we show that only specific-not nonspecific-proteasomal inhibitors can discriminate between malignant and normal lymphocytes in inducing the apoptotic death response. Indeed, lactacystin and its active metabolite clasto-lactacystin beta-lactone induced apoptotic death in CLL but not in normal lymphocytes. This difference was completely abolished when tripeptide aldehydes such as MG132 or LLnL (which can also inhibit calpains) were used as less specific proteasomal inhibitors. Moreover, B-CLL cells exhibited a constitutive altered ubiquitin-proteasome system, including a threefold higher chymotrypsin-like proteasomal activity and high levels of nuclear ubiquitin-conjugated proteins compared with normal lymphocytes. Interestingly, B-CLL cells also displayed altered proteolytic regulation of wild-type p53, an apoptotic factor reported to be a substrate for the ubiquitin-proteasome system. Nuclear wild-type p53 accumulated after lactacystin treatment used at the discriminating concentration in malignant, but not in normal, lymphocytes. In contrast, p53 was stabilized by MG132 or LLnL in malignant and normal cells undergoing apoptosis, indicating that in normal lymphocytes p53 is regulated mainly by calpains and not by the ubiquitin-proteasome system. This work raises the possibility that two different proteolytic pathways controlling p53 stability may be pathologically imbalanced. This could result in modification of apoptosis control, since in CLL-lymphocytes a highly upregulated ubiquitin-proteasome system, which controls p53 stability among other apoptotic factors, was correlated with an increased propensity of these cells to apoptosis triggered by lactacystin.

Detection of minimal residual disease in B chronic lymphocytic leukemia (CLL)

In the absence of specific chromosomal translocations the best method for detecting minimal residual disease (MRD) in B cell malignancies is based on the uniqueness of immunoglobulin (Ig) genes rearrangement. We here report a very sensitive method for assessing MRD in complete hematological remission (CHR) chronic lymphocytic leukemia (CLL) patients as defined by the international workshop on CLL (IWCLL).

PATIENTS

Twelve CLL patients in CHR and complete phenotypic remission (CPR) were included in the study. Eight of them received Fludarabine (FDR), one was treated by Chop regimen, and the remaining 3 were rescued by polychemotherapy followed by autologous bone marrow transplantation (ABMT).

METHODS

DNA extracted from peripheral blood lymphocytes (PBL) of each patient was amplified with VH family specific and framework 3 primers in 5' and a consensus JH primer in 3', before treatment and sequentially after the CPR completion. When no clonal rearrangement could be detected by this assay, the CDR3 sequence specific probe of the clone was used as the 3' primer, associated to the VH family specific primer in 5'. PCR products were analyzed by classical procedures in agarose and/or acrylamide gels.

RESULTS

Mixtures of leukemic cells and normal PBL showed detection of a single leukemic cell among more than 10(5) normal cells. Four out of the 12 patients achieved molecular remission (MR) when employing CDR3 amplification. All 3 autografted patients were in MR, whereas only one out of the 9 patients treated by chemotherapy alone achieved MR. When using a clone specific probe, a clonal signal was observed in all cases but one (ABMT). Results presented here confirm that MR may be achieved in a few cases of B-CLL. Further studies are needed to determine the exact relationship between MRD and clinical outcome.

Autologous hematopoietic stem cell transplantation as salvage treatment for advanced B cell chronic lymphocytic leukemia

Given the generally poor outcome of advanced B cell chronic lymphocytic leukemia, experimental approaches are warranted, especially for younger patients in whom classical treatments have failed. We therefore conducted a prospective single-center study, using polychemotherapy (ESHAP) to prepare patients for hematopoietic stem cell collection and autologous stem cell transplantation as consolidation therapy. Twenty patients entered the study. An adequate response to ESHAP was obtained in 13 patients, and sufficient stem cells for grafting were obtained in eight of the 12 patients who underwent the collection procedure. Six of these grafted patients are alive in complete clinical remission a median of 30 months after transplantation. It should be noted that we were only able to graft 40% of the patients enrolled in this study, either because a new remission could not be obtained or because not enough hematopoietic stem cells could be collected. This argues for stem cell collection as soon as a first remission is obtained, even if the autograft is done later in the course of the disease.

Quantification of apoptosis by the Abbott CD4000 hematology analyzer

We propose a simple and fast method of detecting apoptosis using an automated hematology analyzer. Detection is based on cellular optical light scatter properties and demonstration of the membrane fragility which characterizes cells undergoing the process of apoptosis. As part of it's routine leucocyte differential analysis, the Abbott Cell-Dyn 4000 collects multi-angle cellular light scatter data. In addition red fluorescence (FL3) emitted by cells following propidium iodide labeling is collected. This provides quantitation of both the erythroblast count and a leukocyte viability index (WVF). Fresh or cryopreserved peripheral blood cells from 17 B-chronic lymphocytic leukemia (B-CLL) patients were incubated in presence of theophylline, fludarabine or in medium alone. After 36-hrs of culture the percentage of apoptotic cells of the sample was determined from the parameters of the CD 4000 described above and thereafter this was compared with reference methods for estimation of apoptosis. The reference methods used were in situ detection of cell death on slides (TUNEL test) and also flow cytometry (Annexin V). Results showed an excellent correlation between the 3 techniques. This rapid, easy and reliable method of quantifying apoptosis may be very useful means of routinely predicting the response to chemotherapy.