Gaucher Disease and Myelofibrosis: A Combined Disease or a Misdiagnosis?

Background: Gaucher disease (GD) and primary myelofibrosis (PMF) share similar clinical and laboratory features, such as cytopenia, hepatosplenomegaly, and marrow fibrosis, often resulting in a misdiagnosis. Case Report: We report here the case of a young woman with hepatosplenomegaly, leukopenia, and thrombocytopenia. Based on bone marrow (BM) findings and on liver biopsy showing extramedullary hematopoiesis, an initial diagnosis of PMF was formulated. The patient refused stem cell transplantation from an HLA-identical sibling. Low-dose melphalan was given, without any improvement. Two years later, a BM evaluation showed Gaucher cells. Low glucocerebrosidase and high chitotriosidase levels were indicative for GD. Molecular analysis revealed N370S/complex I mutations. Enzyme replacement therapy with imiglucerase was commenced, resulting in clinical and hematological improvements. Due to an unexpected and persistent organomegaly, PMF combined with GD were suspected. JAK2V617F, JAK2 exon 12, MPL, calreticulin, and exon 9 mutations were negative, and BM examination showed no marrow fibrosis. PMF was excluded. Twenty years after starting treatment, the peripheral cell count and liver size were normal, whereas splenomegaly persisted. Conclusion: In order to avoid a misdiagnosis, a diagnostic algorithm for patients with hepatosplenomegaly combined with cytopenia is suggested

Body mass index does not impact on molecular response rate of chronic myeloid leukaemia patients treated frontline with second generation tyrosine kinase inhibitors.

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Impact of killer-immunoglobulin-like receptor and human leukocyte antigen genotypes on the efficacy of immunotherapy in acute myeloid leukemia

Interactions between killer-immunoglobulin-like receptors (KIRs) and their HLA class I ligands are instrumental in natural killer (NK) cell regulation and protect normal tissue from NK cell attack. Human KIR haplotypes comprise genes encoding mainly inhibitory receptors (KIR A) or activating and inhibitory receptors (KIR B). A substantial fraction of humans lack ligands for inhibitory KIRs (iKIRs), that is, a 'missing ligand' genotype. KIR B/x and missing ligand genotypes may thus give rise to potentially autoreactive, unlicensed NK cells. Little is known regarding the impact of such genotypes in untransplanted acute myeloid leukemia (AML). For this study, NK cell phenotypes and KIR/HLA genotypes were determined in 81 AML patients who received immunotherapy with histamine dihydrochloride and low-dose IL-2 for relapse prevention (NCT01347996). We observed that presence of unlicensed NK cells impacted favorably on clinical outcome, in particular among patients harboring functional NK cells reflected by high expression of the natural cytotoxicity receptor (NCR) NKp46. Genotype analyses suggested that the clinical benefit of high NCR expression was restricted to patients with a missing ligand genotype and/or a KIR B/x genotype. These data imply that functional NK cells are significant anti-leukemic effector cells in patients with KIR/HLA genotypes that favor NK cell autoreactivity

Clinical relevance and treatment of nonautoimmune anemia in chronic lymphocytic leukemia

Anemia has an unfavorable impact on quality of life in chronic lymphocytic leukemia (CLL), increases the likelihood of receiving blood transfusions, and eventually has a negative impact on overall survival. Although discrepancies in perception of health-related quality of life between doctors and patients lead to the undertreatment of anemia, CLL patients undergoing chemotherapy who have a hemoglobin level <10 g/dL should be considered for treatment with erythropoiesis-stimulating agents. For hemoglobin values of 10–12 g/dL, the role of performance status and comorbidities should not be underestimated. In this setting, the evaluation of physical fitness using the Cumulative Illness Rating Scale should help physicians to identify those patients with hemoglobin levels of 10–12 g/dL who are suitable for therapy with erythropoiesis-stimulating agents. Finally, the increasing use of aggressive approaches to therapy should encourage physicians towards appropriate management of chemotherapy-induced anemia in CLL patients

Clinical relevance of silent red blood cell autoantibodies.

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Correlation measurements in high-multiplicity events

Requirements for correlation measurements in high--multiplicity events are discussed. Attention is focussed on detection of so--called hot spots, two--particle rapidity correlations, two--particle momentum correlations (for quantum interferometry) and higher--order correlations. The signal--to--noise ratio may become large in the high--multiplicity limit, allowing meaningful single--event measurements, only if the correlations are due to collective behavior.Comment: MN 55455, 20 pages, KSUCNR-011-92 and TPI-MINN-92/47-T (revised). Revised to correct typo in equation (30), and to fill in a few steps in calculations. Now published as Phys. Rev. C 47 (1993) 232

Tailoring CD19xCD3-DART exposure enhances T-cells to eradication of B-cell neoplasms.

Many patients with B-cell malignancies can be successfully treated, although tumor eradication is rarely achieved. T-cell-directed killing of tumor cells using engineered T-cells or bispecific antibodies is a promising approach for the treatment of hematologic malignancies. We investigated the efficacy of CD19xCD3 DART bispecific antibody in a broad panel of human primary B-cell malignancies. The CD19xCD3 DART identified 2 distinct subsets of patients, in which the neoplastic lymphocytes were eliminated with rapid or slow kinetics. Delayed responses were always overcome by a prolonged or repeated DART exposure. Both CD4 and CD8 effector cytotoxic cells were generated, and DART-mediated killing of CD4+ cells into cytotoxic effectors required the presence of CD8+ cells. Serial exposures to DART led to the exponential expansion of CD4 + and CD8 + cells and to the sequential ablation of neoplastic cells in absence of a PD-L1-mediated exhaustion. Lastly, patient-derived neoplastic B-cells (B-Acute Lymphoblast Leukemia and Diffuse Large B Cell Lymphoma) could be proficiently eradicated in a xenograft mouse model by DART-armed cytokine induced killer (CIK) cells. Collectively, patient tailored DART exposures can result in the effective elimination of CD19 positive leukemia and B-cell lymphoma and the association of bispecific antibodies with unmatched CIK cells represents an effective modality for the treatment of CD19 positive leukemia/lymphoma

Rapid identification of BCR/ABL1-like acute lymphoblastic leukaemia patients using a predictive statistical model based on quantitative real time-polymerase chain reaction: clinical, prognostic and therapeutic implications.

BCR/ABL1-like acute lymphoblastic leukaemia (ALL) is a subgroup of B-lineage acute lymphoblastic leukaemia that occurs within cases without recurrent molecular rearrangements. Gene expression profiling (GEP) can identify these cases but it is expensive and not widely available. Using GEP, we identified 10 genes specifically overexpressed by BCR/ABL1-like ALL cases and used their expression values - assessed by quantitative real time-polymerase chain reaction (Q-RT-PCR) in 26 BCR/ABL1-like and 26 non-BCR/ABL1-like cases to build a statistical "BCR/ABL1-like predictor", for the identification of BCR/ABL1-like cases. By screening 142 B-lineage ALL patients with the "BCR/ABL1-like predictor", we identified 28/142 BCR/ABL1-like patients (19·7%). Overall, BCR/ABL1-like cases were enriched in JAK/STAT mutations (P < 0·001), IKZF1 deletions (P < 0·001) and rearrangements involving cytokine receptors and tyrosine kinases (P = 0·001), thus corroborating the validity of the prediction. Clinically, the BCR/ABL1-like cases identified by the BCR/ABL1-like predictor achieved a lower rate of complete remission (P = 0·014) and a worse event-free survival (P = 0·0009) compared to non-BCR/ABL1-like ALL. Consistently, primary cells from BCR/ABL1-like cases responded in vitro to ponatinib. We propose a simple tool based on Q-RT-PCR and a statistical model that is capable of easily, quickly and reliably identifying BCR/ABL1-like ALL cases at diagnosis

DYNAMICS OF EXPANSION OF TYROSINE KINASE INHIBITOR-RESISTANT MUTANTS AS ASSESSED BY DEEP SEQUENCING OF THE BCR-ABL KINASE DOMAIN: IMPLICATIONS FOR ROUTINE MUTATION TESTING

Background: In Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL) patients (pts), efficacy of tyrosine kinase inhibitor (TKI)-based therapies is often compromised by selection of resistant mutations in the BCR-ABL kinase domain (KD). Currently, the gold standard for BCR-ABL KD mutation screen- ing is conventional Sanger sequencing (SS). However, more sensitive approaches are desirable to allow more timely and rational therapeutic intervention. Aims: A Deep sequencing (DS) strategy based on the Roche 454 next-generation sequencing technology was set up in order to: study the dynamics of expansion of different types of BCR-ABL KD mutations in Ph+ ALL patients developing resistance to TKI-based therapies; test the ability of DS to highlight emerging clones harboring TKI-resistant mutations. Methods: 29 Ph+ ALL pts who had developed resistance to TKI-based (imatinib, dasatinib, nilotinib) therapies were selected for this retrospective analysis. All the pts were known to have developed TKI-resistant BCR-ABL mutations on treatment, as assessed by SS. To reconstruct the dynamics of mutation emergence, longitudinal re-analysis of samples from relapse backwards (n=97; 1-3 months sampling interval) was performed on a Roche GS Junior instru- ment. DS runs were designed so as to enable high sensitivity mutation calling (minimum target sequence coverage 4,000 reads). However, to minimize the likelihood of false positive results, data were analyzed filtering out all variants with &lt;1% abundance. Results: DS could successfully detect all the mutations (n=85) previously identified by SS (&gt;15% abundance). In addition, DS revealed that both those samples that had been scored as apparently wild-type by SS and those samples already known to harbor mutations as assessed by SS might be carrying one or more ‘lower level’ mutations (&lt;15% abundance). In the latter cases, clonal analysis showed complex textures with the same mutation alone and also in combination with other(s) (‘compound’ mutations) in distinct subclones. Some lower level mutations were silent or apparently irrelevant from a clinical standpoint (passenger mutations?). In more than half of the cases, however, known TKI-resistant variants could be recognized that corresponded either to ‘withdrawing’ mutants not (yet) entirely de-selected by the switch in TKI or to outgrowing mutations anticipating an imminent relapse. Lower level mutations were confirmed with independent methods (ASO-PCR, RFLP). Notably, in 16/29 (55%) pts with molecularly detectable disease but not yet evidence of cytogenetic or hematologic relapse, DS could identify emerging mutations 1 to 3 months before they became detectable by SS. In the remaining 13 pts, however, outgrowth of the TKI-resistant mutation (T315I=7, Y253H=2, E255K=2, E255V=1 and F317L=1) was so rapid that not even a strict monthly monitoring could have allowed to pick them up before they became dominant. Summary / Conclusion: Now that multiple options are available, BCR-ABL KD mutation monitoring is a precious tool to maximize the efficacy of TKI-based regimens as induction or salvage therapy of Ph+ ALL. DS proved as reliable as SS for the detection of mutations with &gt;15% abundance. As a key advantage, DS added precious quantitative and qualitative information on the full repertoire of mutated populations, that SS underestimated in more than half of the samples analyzed. TKI-resistant mutations leading to patient relapse were not necessarily preexisting at diagnosis or at the time of switchover to another TKI, underlining the importance of regular monitoring of pts. Although the majority of mutations were found to arise and take over very rapidly, a monthly monitoring by our DS approach would have allowed to identify them earlier than SS actually did - and well in advance of clinical relapse - in half of the pts. DS technologies would enable higher sensitivity mutation calling: further studies are warranted to determine the optimal lower detection limit to aim to in order to exclude both transient mutant subclones that will never take over and sequencing errors

Rituximab in B-Cell Hematologic Malignancies: A Review of 20 Years of Clinical Experience

Rituximab is a human/murine, chimeric anti-CD20 monoclonal antibody with established efficacy, and a favorable and well-defined safety profile in patients with various CD20-expressing lymphoid malignancies, including indolent and aggressive forms of B-cell non-Hodgkin lymphoma. Since its first approval 20 years ago, intravenously administered rituximab has revolutionized the treatment of B-cell malignancies and has become a standard component of care for follicular lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia, and mantle cell lymphoma. For all of these diseases, clinical trials have demonstrated that rituximab not only prolongs the time to disease progression but also extends overall survival. Efficacy benefits have also been shown in patients with marginal zone lymphoma and in more aggressive diseases such as Burkitt lymphoma. Although the proven clinical efficacy and success of rituximab has led to the development of other anti-CD20 monoclonal antibodies in recent years (e.g., obinutuzumab, ofatumumab, veltuzumab, and ocrelizumab), rituximab is likely to maintain a position within the therapeutic armamentarium because it is well established with a long history of successful clinical use. Furthermore, a subcutaneous formulation of the drug has been approved both in the EU and in the USA for the treatment of B-cell malignancies. Using the wealth of data published on rituximab during the last two decades, we review the preclinical development of rituximab and the clinical experience gained in the treatment of hematologic B-cell malignancies, with a focus on the well-established intravenous route of administration. This article is a companion paper to A. Davies, et al., which is also published in this issue