Acute promyelocytic leukemia with torque teno mini virus (TTMV)::RARA fusion: an approach to screening and diagnosis

Acute promyelocytic leukemia (APL) with variant RARA translocation is linked to over 15 partner genes. Recent publications encompassing six cases have expanded the spectrum of RARA partners to torque teno mini virus (TTMV). This entity is likely under-recognized due to lack of clinician and pathologist familiarity, inability to detect the fusion using routine testing modalities, and informatic challenges in its recognition within next-generation sequencing (NGS) data. We describe a clinicopathologic approach and provide necessary tools to screen and diagnose APL with TTMV::RARA using existing clinical DNA or RNA-based NGS assays, which led to identification of four cases, all without other known cytogenetic/molecular drivers. One was identified prospectively and three retrospectively, including two from custom automated screening of multiple data sets (50 257 cases of hematopoietic malignancy, including 4809 acute myeloid leukemia (AML)/myeloid sarcoma/APL cases). Two cases presented as myeloid sarcoma, including one with multiple relapses after AML-type chemotherapy and hematopoietic stem cell transplant (HSCT). Two cases presented as leukemia, had a poor response to induction chemotherapy, but achieved remission upon re-induction (including all-trans retinoic acid (ATRA) in one case) and subsequent HSCT. Neoplastic cells demonstrated features of APL including frequent azurophilic granules and dim/absent CD34 and HLA-DR expression. RARA rearrangement was not detected by karyotype or FISH. Custom analysis of NGS fusion panel data identified TTMV::RARA rearrangements, and in the prospectively identified case, facilitated monitoring in sequential bone marrow samples. APL with TTMV::RARA is a rare leukemia with a high rate of treatment failure in described cases. The diagnosis should be considered in leukemias with features of APL that lack detectable RARA fusions and other drivers, and may be confirmed by appropriate NGS tests with custom informatics. Incorporation of ATRA may have a role in treatment but requires accurate recognition of the fusion for appropriate classification as APL.

Recommendations for using artificial intelligence in clinical flow cytometry

Flow cytometry is a key clinical tool in the diagnosis of many hematologic malignancies and traditionally requires close inspection of digital data by hematopathologists with expert domain knowledge. Advances in artificial intelligence (AI) are transferable to flow cytometry and have the potential to improve efficiency and prioritization of cases, reduce errors, and highlight fundamental, previously unrecognized associations with underlying biological processes. As a multidisciplinary group of stakeholders, we review a range of critical considerations for appropriately applying AI to clinical flow cytometry, including use case identification, low and high risk use cases, validation, revalidation, computational considerations, and the present regulatory frameworks surrounding AI in clinical medicine. In particular, we provide practical guidance for the development, implementation, and suggestions for potential regulation of AI-based methods in the clinical flow cytometry laboratory. We expect these recommendations to be a helpful initial framework of reference, which will also require additional updates as the field matures.

Translating the regulatory landscape of medical devices to create fit-for-purpose artificial intelligence (AI) cytometry solutions

The implementation of medical software and artificial intelligence (AI) algorithms into routine clinical cytometry diagnostic practice requires a thorough understanding of regulatory requirements and challenges throughout the cytometry software product lifecycle. To provide cytometry software developers, computational scientists, researchers, industry professionals, and diagnostic physicians/pathologists with an introduction to European Union (EU) and United States (US) regulatory frameworks. Informed by community feedback and needs assessment established during two international cytometry workshops, this article provides an overview of regulatory landscapes as they pertain to the application of AI, AI-enabled medical devices, and Software as a Medical Device in diagnostic flow cytometry. Evolving regulatory frameworks are discussed, and specific examples regarding cytometry instruments, analysis software and clinical flow cytometry in-vitro diagnostic assays are provided. An important consideration for cytometry software development is the modular approach. As such, modules can be segregated and treated as independent components based on the medical purpose and risk and become subjected to a range of context-dependent compliance and regulatory requirements throughout their life cycle. Knowledge of regulatory and compliance requirements enhances the communication and collaboration between developers, researchers, end-users and regulators. This connection is essential to translate scientific innovation into diagnostic practice and to continue to shape the development and revision of new policies, standards, and approaches.

Cutaneous Manifestations of Myeloid Neoplasms Exhibit Broad and Divergent Morphologic and Immunophenotypic Features but Share Ancestral Clonal Mutations With Bone Marrow

In this study, we performed a comprehensive molecular analysis of paired skin and peripheral blood/bone marrow (BM) samples from 17 patients with cutaneous myeloid or cutaneous histiocytic-dendritic neoplasms. The cutaneous manifestations included 10 patients with cutaneous acute myeloid leukemia (c-AML), 2 patients with full or partial Langerhans cell differentiation, 2 patients with blastic plasmacytoid dendritic cell neoplasms (BPDCN), 1 patient with both Langerhans cell differentiation and BPDCN, and 2 patients with full or partial indeterminate dendritic cell differentiation. Seven of the 10 c-AML patients (70%) exhibited concurrent or subsequent marrow involvement by acute myeloid leukemia, with all 7 cases (100%) demonstrating shared clonal mutations in both the skin and BM. However, clonal relatedness was documented in one additional case that never had any BM involvement. Nevertheless, NPM1 mutations were identified in 7 of the 10 (70%) of these c-AML cases while one had KMT2A rearrangement and one showed inv(16). All 3 patients (100%) with Langerhans cell neoplasms, 2 patients with BPDCN (100%), and one of the 2 patients (50%) with other cutaneous dendritic cell neoplasms also demonstrated shared mutations between the skin and concurrent or subsequent myeloid neoplasms. Both BM and c-AML shared identical founding drivers, with a predominance of NPM1, DNMT3A, and translocations associated with monocytic differentiation, with common cutaneous-only mutations involving genes in the signal transduction and epigenetic pathways. Cutaneous histiocytic-dendritic neoplasms shared founding drivers in ASXL1, TET2, and/or SRSF2. However, in the Langerhans cell histiocytosis or histiocytic sarcoma cases, there exist recurrent secondary RAS pathway hits, whereas cutaneous BPDCN cases exhibit copy number or structural variants. These results enrich and broaden our understanding of clonally related cutaneous manifestations of myeloid neoplasms and further illuminate the highly diverse spectrum of morphologic and immunophenotypic features they exhibit.

One-year retrospective analysis of anti-FXa apixaban and rivaroxaban levels demonstrates utility for management decisions in various urgent and nonurgent clinical situations

OBJECTIVES

Quantification of direct oral anticoagulant (DOAC) plasma levels can guide clinical management, but insight into clinical scenarios surrounding DOAC-calibrated anti-FXa assays is limited.

METHODS

Apixaban- and rivaroxaban-calibrated chromogenic anti-Xa assays performed over a 1-year period were retrospectively analyzed. Patient demographics, DOAC history, concomitant medications, and renal/liver comorbidities were obtained. Indications for testing and associated clinical actions were reviewed. Machine learning (ML) models predicting clinical actions were evaluated.

RESULTS

In total, 371 anti-FXa apixaban and 89 anti-FXa rivaroxaban tests were performed for 259 and 67 patients in recurring urgent (acute bleeding, unplanned procedures) and nonurgent situations, including several scenarios not captured by existing testing recommendations (eg, drug monitoring, recurrent thromboembolic events, bleeding tendency). In urgent settings, andexanet reversal was guided by radiologic and clinical findings over DOAC levels in 14 of 32 instances, while 51% of apixaban patients qualified for nonreversal strategies through the availability of levels. Levels also informed procedure/intervention timing and supported management decisions when DOAC clearance or DOAC target levels were in question. The importance of clinical context was emphasized by exploratory ML models predicting particular clinical actions.

CONCLUSIONS

Although clinical situations are complex, DOAC testing facilitates clinical decision-making, including reversal, justifying more widespread implementation of these assays.

Advances in Acute Myeloid Leukemia Classification, Prognostication and Monitoring by Flow Cytometry

Although final classification of acute myeloid leukemia (AML) integrates morphologic, cytogenetic, and molecular data, flow cytometry remains an essential component of modern AML diagnostics. Here, we review the current role of flow cytometry in the classification, prognostication, and monitoring of AML. We cover immunophenotypic features of key genetically defined AML subtypes and their effects on biological and clinical behaviors, review clinically tractable strategies to differentiate leukemias with ambiguous immunophenotypes more accurately and discuss key principles of standardization for measurable residual disease monitoring. These advances underscore flow cytometry's continued growth as a powerful diagnostic, management, and discovery tool.

In Vivo Modeling of CLL Transformation to Richter Syndrome Reveals Convergent Evolutionary Paths and Therapeutic Vulnerabilities

Transformation to aggressive disease histologies generates formidable clinical challenges across cancers, but biological insights remain few. We modeled the genetic heterogeneity of chronic lymphocytic leukemia (CLL) through multiplexed in vivo CRISPR-Cas9 B-cell editing of recurrent CLL loss-of-function drivers in mice and recapitulated the process of transformation from indolent CLL into large cell lymphoma [i.e., Richter syndrome (RS)]. Evolutionary trajectories of 64 mice carrying diverse combinatorial gene assortments revealed coselection of mutations in Trp53, Mga, and Chd2 and the dual impact of clonal Mga/Chd2 mutations on E2F/MYC and interferon signaling dysregulation. Comparative human and murine RS analyses demonstrated tonic PI3K signaling as a key feature of transformed disease, with constitutive activation of the AKT and S6 kinases, downmodulation of the PTEN phosphatase, and convergent activation of MYC/PI3K transcriptional programs underlying enhanced sensitivity to MYC/mTOR/PI3K inhibition. This robust experimental system presents a unique framework to study lymphoid biology and therapy.

SIGNIFICANCE

Mouse models reflective of the genetic complexity and heterogeneity of human tumors remain few, including those able to recapitulate transformation to aggressive disease histologies. Herein, we model CLL transformation into RS through multiplexed in vivo gene editing, providing key insight into the pathophysiology and therapeutic vulnerabilities of transformed disease. This article is highlighted in the In This Issue feature, p. 101.

DeepHeme: A generalizable, bone marrow classifier with hematopathologist-level performance

Morphology-based classification of cells in the bone marrow aspirate (BMA) is a key step in the diagnosis and management of hematologic malignancies. However, it is time-intensive and must be performed by expert hematopathologists and laboratory professionals. We curated a large, high-quality dataset of 41,595 hematopathologist consensus-annotated single-cell images extracted from BMA whole slide images (WSIs) containing 23 morphologic classes from the clinical archives of the University of California, San Francisco. We trained a convolutional neural network, DeepHeme, to classify images in this dataset, achieving a mean area under the curve (AUC) of 0.99. DeepHeme was then externally validated on WSIs from Memorial Sloan Kettering Cancer Center, with a similar AUC of 0.98, demonstrating robust generalization. When compared to individual hematopathologists from three different top academic medical centers, the algorithm outperformed all three. Finally, DeepHeme reliably identified cell states such as mitosis, paving the way for image-based quantification of mitotic index in a cell-specific manner, which may have important clinical applications.

Hematopathology of SARS-CoV-2 infection and COVID-19 disease

Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 and is associated with pronounced hematopathologic findings. Peripheral blood features are heterogeneous and very often include neutrophilia, lymphopenia, myeloid left shift, abnormally segmented neutrophils, atypical lymphocytes/plasmacytoid lymphocytes, and atypical monocytes. Bone marrow biopsies and aspirates are often notable for histiocytosis and hemophagocytosis, whereas secondary lymphoid organs may exhibit lymphocyte depletion, pronounced plasmacytoid infiltrates, and hemophagocytosis. These changes are reflective of profound innate and adaptive immune dysregulation, and ongoing research efforts continue to identify clinically applicable biomarkers of disease severity and outcome.

Correctly Establishing and Interpreting Oxygenation Status in Sickle Cell Disease

BACKGROUND

As hypoxemia and hypoxia are central elements of disease pathophysiology and disease-related morbidity and mortality in individuals affected by sickle cell disease (SCD), clinical management aims to optimize oxygenation.

CONTENT

Hypoxemia is primarily screened for with pulse oximetry. However, in SCD pulse oximetry can inaccurately reflect arterial saturation, posing the risk of undetected (occult) hypoxemia. Solely relying on pulse oximetry might therefore lead to misdiagnosis or mismanagement, with devastating effects on tissue oxygenation. The interpretation of oxygenation status is multifaceted, and "oxygen saturation" is often used as an umbrella term to refer to distinctly different measured quantities-estimated oxygen saturation (O2Sat), hemoglobin oxygen saturation (SO2) by either pulse oximetry or co-oximetry, and fractional oxyhemoglobin (FO2Hb). While in many clinical situations this ambiguous use is of little consequence, O2Sat, SO2, and FO2Hb cannot be used interchangeably in the setting of SCD, as dyshemoglobins, anemia, cardiopulmonary comorbidities, concomitant medications, and frequent transfusions need to be accounted for. This article describes the parameters that determine blood and tissue oxygen concentration, discusses laboratory method performance characteristics and the correct interpretation of currently available clinical laboratory testing, and reviews the literature on noninvasive vs invasive oxygenation measurements in SCD.

SUMMARY

By correctly establishing and interpreting oxygenation parameters, clinical and laboratory teams can ensure high-quality, equitable healthcare, counteracting systemic exacerbations of health disparities frequently experienced by individuals with SCD.

Factors influencing complications after 3-columns spinal osteotomies for fixed sagittal imbalance from multiple etiologies: a multicentric cohort study about 286 cases in 273 patients

PURPOSE

Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies.

METHODS

The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicenter cohort of patients who underwent 3-columns (3C) spinal osteotomy, between January 2010 and January 2017. Clinical and radiological data were compared pre- and post-operatively. Complications and their risk factors were analyzed.

RESULTS

Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1 year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p < 0.001). A total of 164 patients (59.2%) experienced at least 1 complication (277 complications). Complications-free survival rates were only 30% at 5 years. Most of those were mechanical (35.2%), followed by general (17.6%), surgical site infection (17.2%) and neurological (10.9%). Pre-operative neurological status [RR = 2.3 (1.32-4.00)], operative time (+ 19% of risk each additional hour) and combined surgery [RR = 1.76 (1.08-2.04)] were assessed as risk factors for overall complication (p < 0.05). The use of patient-specific rods appeared to be significantly associated with less overall complications [RR = 0.5 (0.29-0.89)] (p = 0.02).

CONCLUSION

Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

A Potassium-Based Quality-of-Service Metric Reduces Phlebotomy Errors, Resulting in Improved Patient Safety and Decreased Cost

OBJECTIVES

Poor phlebotomy technique can introduce pseudohyperkalemia without hemolysis, requiring additional workup and placing a significant burden on patients, clinical teams, and laboratories. Such preanalytical biases can be detected through systematic evaluation of potassium concentrations on a per-phlebotomist basis. We report our long-term experience with a potassium-based quality-of-service phlebotomy metric and its effects on resource utilization.

METHODS

Potassium monitoring and retraining of 26 full-time phlebotomists were piloted as a quality-of-service intervention. Changes in potassium concentrations and impact on resource utilization were assessed. An algorithm for data monitoring and phlebotomist feedback was developed, followed by institution-wide implementation.

RESULTS

Systematic intervention and retraining normalized K+ concentrations and lowered the percentage of venipunctures with K+ above 5.2 mmol/L, leading to a marked increase in phlebotomist compliance. This change resulted in resources savings of 13% to 100% for individual phlebotomists, reducing the total extra laboratory time required for repeat phlebotomies to determine hyperkalemia, mostly in the high-volume phlebotomist group.

CONCLUSIONS

A quality-of-service algorithm that involved monitoring potassium concentrations on a per-phlebotomist basis with feedback and retraining contributed to a concrete, data-based quality improvement plan. The institution-wide implementation of this metric allowed for significant cost savings and a reduction in critical value alerts, directly affecting the quality of patient care.

Adding venetoclax to fludarabine/busulfan RIC transplant for high-risk MDS and AML is feasible, safe, and active

Adding the selective BCL-2 inhibitor venetoclax to reduced-intensity conditioning chemotherapy (fludarabine and busulfan [FluBu2]) may enhance antileukemic cytotoxicity and thereby reduce the risk of posttransplant relapse. This phase 1 study investigated the recommended phase 2 dose (RP2D) of venetoclax, a BCL-2 selective inhibitor, when added to FluBu2 in adult patients with high-risk acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), and MDS/myeloproliferative neoplasms (MPN) undergoing transplant. Patients received dose-escalated venetoclax (200-400 mg daily starting day -8 for 6-7 doses) in combination with fludarabine 30 mg/m2 per day for 4 doses and busulfan 0.8 mg/kg twice daily for 8 doses on day -5 to day -2 (FluBu2). Transplant related-toxicity was evaluated from the first venetoclax dose on day -8 to day 28. Twenty-two patients were treated. At study entry, 5 patients with MDS and MDS/MPN had 5% to 10% marrow blasts, and 18 (82%) of 22 had a persistent detectable mutation. Grade 3 adverse events included mucositis, diarrhea, and liver transaminitis (n = 3 each). Neutrophil/platelet recovery and acute/chronic graft-versus-host-disease rates were similar to those of standard FluBu2. No dose-limiting toxicities were observed. The RP2D of venetoclax was 400 mg daily for 7 doses. With a median follow-up of 14.7 months (range, 8.6-24.8 months), median overall survival was not reached, and progression-free survival was 12.2 months (95% confidence interval, 6.0-not estimable). In patients with high-risk AML, MDS, and MDS/MPN, adding venetoclax to FluBu2 was feasible and safe. To further address relapse risk, assessment of maintenance therapy after venetoclax plus FluBu2 transplant is ongoing. This study was registered at clinicaltrials.gov as #NCT03613532.

Activation of Notch and Myc Signaling via B-cell-Restricted Depletion of Dnmt3a Generates a Consistent Murine Model of Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is characterized by disordered DNA methylation, suggesting these epigenetic changes might play a critical role in disease onset and progression. The methyltransferase DNMT3A is a key regulator of DNA methylation. Although DNMT3A somatic mutations in CLL are rare, we found that low DNMT3A expression is associated with more aggressive disease. A conditional knockout mouse model showed that homozygous depletion of Dnmt3a from B cells results in the development of CLL with 100% penetrance at a median age of onset of 5.3 months, and heterozygous Dnmt3a depletion yields a disease penetrance of 89% with a median onset at 18.5 months, confirming its role as a haploinsufficient tumor suppressor. B1a cells were confirmed as the cell of origin of disease in this model, and Dnmt3a depletion resulted in focal hypomethylation and activation of Notch and Myc signaling. Amplification of chromosome 15 containing the Myc gene was detected in all CLL mice tested, and infiltration of high-Myc-expressing CLL cells in the spleen was observed. Notably, hyperactivation of Notch and Myc signaling was exclusively observed in the Dnmt3a CLL mice, but not in three other CLL mouse models tested (Sf3b1-Atm, Ikzf3, and MDR), and Dnmt3a-depleted CLL were sensitive to pharmacologic inhibition of Notch signaling in vitro and in vivo. Consistent with these findings, human CLL samples with lower DNMT3A expression were more sensitive to Notch inhibition than those with higher DNMT3A expression. Altogether, these results suggest that Dnmt3a depletion induces CLL that is highly dependent on activation of Notch and Myc signaling. SIGNIFICANCE: Loss of DNMT3A expression is a driving event in CLL and is associated with aggressive disease, activation of Notch and Myc signaling, and enhanced sensitivity to Notch inhibition.

Rivaroxaban-calibrated chromogenic anti-Xa assay in cirrhosis: Use to rule out disseminated intravascular coagulation

Peritoneovenous shunts (PVSs) are used to relieve ascites in cirrhosis. Disseminated intervascular coagulation (DIC) is a complication of PVSs requiring immediate PVS removal. We report a patient who developed new elevations of prothrombin time (PT) and activated partial thromboplastin time (aPTT) 6 hours after PVS placement, concerning for new-onset DIC. We address the key clinical question of distinguishing DIC from rivaroxaban effect on labs. The patient took rivaroxaban 3 hours after PVS placement, suggesting rivaroxaban effect. Rivaroxaban-calibrated anti-Xa level was in the expected treatment range. Over 12 hours, coagulation labs and rivaroxaban levels declined, with no evidence of DIC. The sudden PT/aPTT increase was attributed to rivaroxaban, however, the distinction between DIC and rivaroxaban effect was possible only with the rapid availability of rivaroxaban levels. While there are no US Food and Drug Administration-approved tests for rivaroxaban levels in the United States, this case demonstrates they can have significant clinical impact, encouraging more widespread adaptation of these assays.

Novel BCL2 mutations in venetoclax-resistant, ibrutinib-resistant CLL patients with BTK/PLCG2 mutations

Lucas et al explored the clonal dynamics of chronic lymphocytic leukemia (CLL) patients following treatment and subsequent acquired resistance to ibrutinib and then venetoclax. They report different patterns of resistance mutations from previously reported changes following venetoclax treatment in the absence of prior BTK inhibitor therapy.

Inhibiting Bruton's Tyrosine Kinase in CLL and Other B-Cell Malignancies

Inhibitors of Bruton's tyrosine kinase (BTK), a major kinase in the B-cell receptor (BCR) signaling pathway, mediating B-cell proliferation and apoptosis, have substantially altered the management, clinical course, and outcome of patients with B-cell malignancies. This is especially true for patients with previously limited treatment options due to disease characteristics or coexisting diseases. Ibrutinib was the first orally available, nonselective and irreversible inhibitor of BTK approved for the treatment of patients with various B-cell malignancies. Newer and more selective BTK inhibitors are currently in clinical development, including acalabrutinib, which is currently US FDA approved for previously treated mantle cell lymphoma. Significant efforts are underway to investigate the optimal combinations, timing, and sequencing of BTK inhibitors with other regimens and targeted agents, and to capitalize on the immunomodulatory modes of action of BTK inhibitors to correct tumor-induced immune defects and to achieve long-lasting tumor control. This review describes the major milestones in the clinical development of BTK inhibitors in chronic lymphocytic leukemia and other B-cell malignancies, highlights the most recent long-term follow-up results, and evaluates the role of BTK inhibitors and their combination with other agents in B-cell malignancies and other indications.

MiSet RFC Standards: Defining a Universal Minimum Set of Standards Required for Reproducibility and Rigor in Research Flow Cytometry Experiments

Poor adherence to best practices, insufficient training, and pressure to produce data quickly may lead to publications of suboptimal biomedical research flow cytometry data, which contributes to the body of irreproducible research findings. In addition, documentation of compliance with best flow cytometry practices for submission, visualization, and publication of flow cytometry data is currently endorsed by very few scientific journals, which is particularly concerning as numerous peer-reviewed flow cytometry publications emphasize instrumentation, experimental design, and data analysis as important sources of variability. Guidelines and resources for adequate reporting, annotation and deposition of flow cytometry experiments are provided by MIFlowCyt and the FlowRepository database, and comprehensive expert recommendations covering principles and techniques of field-specific flow cytometry applications have been published. To facilitate the integration of quality-defining parameters into manuscript and grant submission and publication requirements across biomedical fields that rely on the use of flow-cytometry-based techniques, a single comprehensive yet easily and universally applicable document is needed. To produce such a list of gold-standard parameters that assess whether a research flow cytometry experiment has been planned, conducted, interpreted, and reported at the highest standard, a new initiative defining the minimum set of standards a robust and rigorous research flow experiment must fulfill (MiSet RFC Standards) was proposed at CYTO 2019. MiSet RFC Standards will integrate and simplify existing resources to provide a universal benchmark a flow cytometry experiment can easily be measured against. The goal of MiSET RFC Standards is its integration into peer-review and publication procedures through partnership with stakeholders, journals and publishers in biomedical and translational research. This article introduces the aims and anticipated timeline and discusses strategies for interdisciplinary consensus and implementation. A single-resource broadly applicable guideline will harmonize standards across different fields of biomedical research and lead to publication of more robust research findings. © 2019 International Society for Advancement of Cytometry.

Eμ-TCL1xMyc: A Novel Mouse Model for Concurrent CLL and B-Cell Lymphoma

PURPOSE

Aberrant Myc expression is a major factor in the pathogenesis of aggressive lymphoma, and these lymphomas, while clinically heterogeneous, often are resistant to currently available treatments and have poor survival. Myc expression can also be seen in aggressive lymphomas that are observed in the context of CLL, and we sought to develop a mouse model that could be used to study therapeutic strategies for aggressive lymphoma in the context of CLL.

EXPERIMENTAL DESIGN

We crossed the Eμ-TCL1 mouse model with the Eμ-Myc mouse model to investigate the clinical phenotype associated with B-cell-restricted expression of these oncogenes. The resulting malignancy was then extensively characterized, from both a clinical and biologic perspective.

RESULTS

Eμ-TCL1xMyc mice uniformly developed highly aggressive lymphoid disease with histologically, immunophenotypically, and molecularly distinct concurrent CLL and B-cell lymphoma, leading to a significantly reduced lifespan. Injection of cells from diseased Eμ-TCL1xMyc into WT mice established a disease similar to that in the double-transgenic mice. Both Eμ-TCL1xMyc mice and mice with disease after adoptive transfer failed to respond to ibrutinib. Effective and durable disease control was, however, observed by selective inhibition of nuclear export protein exportin-1 (XPO1) using a compound currently in clinical development for relapsed/refractory malignancies, including CLL and lymphoma.

CONCLUSIONS

The Eμ-TCL1xMyc mouse is a new preclinical tool for testing experimental drugs for aggressive B-cell lymphoma, including in the context of CLL.

T Cell Transcriptional Profiling and Immunophenotyping Uncover LAG3 as a Potential Significant Target of Immune Modulation in Multiple Myeloma

Autologous stem cell transplant (ASCT) is the standard of care for patients with multiple myeloma (MM). The clinical significance of peripheral blood T lymphocyte (PBTL) immunologic changes associated with ASCT is poorly understood. Here we evaluated T cell transcriptional messenger RNA profiles and immunophenotypes to correlate immunologic senescence, exhaustion, and anergy with clinical endpoints in a cohort of patients with MM undergoing ASCT. ASCT induced global transcriptional T cell changes and altered molecular levels of markers of T cell subtypes, T cell activation, and exhaustion. These included reduced CD4/CD8 ratio, skewing toward the Th1 subset, reduced expression of costimulatory receptors CD27 and CD28, heightened T cell activation, and increased expression of immune modulatory molecules LAG3 and PD1. Multicolor flow cytometry experiments confirmed altered circulating CD4 and CD8 subsets and skewing toward differentiated effector cells. Moreover, ASCT promoted an exhausted immunophenotype in CD3⁺CD4⁺ subsets and a senescent immunophenotype in CD3⁺CD8⁺ subsets. Subset-specific altered expression was also seen for surface molecules with immunomodulatory function. ASCT affected soluble levels of molecules with immunomodulatory function by increasing plasma HVEM and TIM3. High molecular LAG3 level was associated with inferior event-free survival post-ASCT (hazard ratio = 5.44; confidence interval, 1.92 to 15.46; P = .001; adjusted P [controlling for false discovery rate] = .038). Using a comprehensive evaluation of PBTLs on a molecular and phenotypic level, we have identified that ASCT induces global T cell alterations with CD4 and CD8 subset-specific changes. Moreover, LAG3 emerged as an early biomarker of adverse events post-ASCT. These findings will support the development of treatment strategies targeting immune defects in MM to augment or restore T cell responses.

Tumor necrosis factor receptor signaling is a driver of chronic lymphocytic leukemia that can be therapeutically targeted by the flavonoid wogonin

Chronic lymphocytic leukemia is a malignancy of mature B cells that strongly depend on microenvironmental factors, and their deprivation has been identified as a promising treatment approach for this incurable disease. Cytokine array screening of 247 chronic lymphocytic leukemia serum samples revealed elevated levels of tumor necrosis factor (TNF) receptor-1 which were associated with poor clinical outcome. We detected a microenvironment-induced expression of TNF receptor-1 in chronic lymphocytic leukemia cells in vitro, and an aberrantly high expression of this receptor in the proliferation centers of patients’ lymph nodes. Stimulation of TNF receptor-1 with TNF-α enhanced nuclear factor κ-light-chain-enhancer of activated B cells (NFκB) activity and viability of chronic lymphocytic leukemia cells, which was inhibited by wogonin. The therapeutic effects of wogonin were analyzed in mice after adoptive transfer of Eμ-T-cell leukemia 1 (TCL1) leukemic cells. Wogonin treatment prevented leukemia development when given early after transplantation. The treatment of full-blown leukemia resulted in the loss of the TNF receptor-1 on chronic lymphocytic leukemia cells and their mobilization to blood. Targeting TNF receptor-1 signaling is therefore proposed for the treatment of chronic lymphocytic leukemia.

Descompresión endoscópica del túnel cubital, técnica y experiencia

Objetivo: Presentar la técnica de liberación endoscópica del nervio cubital en el codo así como los resultados obtenidos en nuestra experiencia.

Material y métodos: Se recogieron prospectivamente datos de 16 pacientes a los que se realizó una descompresión endoscópica del nervio cubital en el codo en un período de tres años. Se empleó la clasificación de McGowan modificada y la electromiografía para el estadiaje preoperatorio. Los resultados postoperatorios fueron evaluados mediante la clasificación de Wilson & Krout y la escala de valoración de la Clínica Mayo. En la clasificación preoperatoria un paciente (6,25%) correspondía al grado 1, 9 (56,2%) al grado 2A, 4 (25%) al grado 2B y 2 (12,5%) al grado 3.

Resultados: 6 pacientes (37,5%) presentaban resultados excelentes, 8 (50%) buen resultado y 2 (12,5%) resultados regulares o aceptables según la clasificación de Wilson & Krout. Según la escala de valoración de la Clínica Mayo,12 pacientes (75%) presentaban resultados excelentes, 3 (18,75%) buenos resultados y 1 (6,25%) resultado regular. El tiempo medio desde la cirugía hasta la reincorporación laboral fue de 36 días (rango de 17 a 52).

Conclusión: La descompresión endoscópica del nervio cubital es una técnica poco invasiva, segura, fiable y con buenos resultados.

Cervical pedicular agenesis: Case report and a review of the literature

Cervical pedicular agenesis, an unusual disorder, is a rare clinical and radiological finding, which can lead to misdiagnosis, moreover in a traumatic situation. The authors report the case of a young woman with a C3 right congenital absence of the cervical pedicle. A systematic review of literature found more than 70 reported cases. In patients with congenital agenesis of the cervical pedicle, the two most common levels of this congenital absence are C6 and C5. The three radiological findings were: the false appearance of an enlarged ipsilateral neural foramen due to the absent pedicle; a dysplastic, dorsally displaced ipsilateral articular pillar and lamina; and a dysplastic ipsilateral transverse process. These pedicle ageneses are a stable congenital anomaly.

Abstract 1029: MAPK-mediated immunomodulation in disseminated murine Emu-TCL1 chronic lymphocytic leukemia

Work in melanoma and other solid tumors shows mutations activating MAPK pathway not only promote malignancy by promoting survival and proliferation but also are immunosuppressive than wild-type (WT) counterparts. However, relevance of MAPK-activating mutations to immune modulation in disseminated cancers such as leukemia is uncertain, and the mechanisms by which this occurs are likely to differ. BRAF activating mutation is found in nearly all hairy cell leukemia cases, 4% of chronic lymphocytic leukemia (CLL) and 9% CLL cases when including other MAPK-activating mutations such as KRAS and NRAS. To assess immunomodulatory effects of BRAF-mutant CLL cells, we co-cultured dox-inducible OSU-CLL cells transfected with WT or BRAFV600E constructs with healthy donor T cells incubated with anti-CD3/anti-CD28 antibodies, and T cell proliferation, cytokine production and expression of surface proteins were assessed by flow cytometry. We also employed a transgenic mouse model of BRAF B cell leukemia. CD19-Cre x BRAFV600E or CD19-Cre only mice were crossed with the well-characterized Emu-TCL1 model of CLL to obtain mice with spontaneous B cell leukemia expressing either WT BRAF (CD19-Cre xTCL1) or mutant BRAF (BRAFV600E xCD19-Cre xTCL1) under the native BRAF promoter. For adoptive transfer (AT) experiments, leukemia cells (2e7) from transgenic mice were engrafted intravenously into syngeneic healthy adult animals. Blood and spleen cells were examined by flow cytometry. OSU-CLL cells expressing BRAFV600E more strongly inhibited anti-CD3/CD28-induced proliferation of normal donor T cells. Transwell assays showed this effect was due both to soluble and contact-dependent factors. TNF levels were higher in BRAFV600E-expressing cells and reduced by vemurafenib, but a TNF neutralizing antibody did not alter the inhibitory effect of BRAFV600E-expressing cells on T cell proliferation. Proliferation was rescued by the BRAFV600E inhibitor dabrafenib, further supporting the contribution of mutant BRAF to this effect. Impact of BRAFV600E mutation on myeloid compartment was also evaluated using AT model. Mice were engrafted with BRAFWT or BRAFV600E leukemia cells, and upon achieving similar disease loads, BRAFV600E leukemic B cells caused 2.2-fold increase in PD-L1 expressing-peripheral myeloid cells (p&lt;0.001; n=25 WT; 11 mutant). Additionally, there was an increase in F4/80+ macrophages (11%; p=0.002), CD11b+Ly6CintLy6Ghi MDSCs (8.5%, p=0.014) and decrease in CD11b+Ly6CloLy6Glo patrolling monocytes (11%; p=0.031; n=33 WT; 40 mutant) in spleens of mice with BRAFV600E leukemia, indicating that this mutation influences the myeloid cell compartment as well. Ongoing studies are investigating the mechanism of these effects and the potential for pharmacologic reversal. Together, these results demonstrate immunosuppressive impact of BRAF in B-cell leukemia.

Citation Format: Aparna Lakshmanan, Yo-Ting Tsai, Amy Lehman, Ellen J. Sass, Minh Tran, Fabienne Lucas, Meixiao Long, Bonnie K. Harrington, Krista La Perle, Vincenzo Coppola, Gerard Lozanski, Natarajan Muthusamy, John C. Byrd, Michael R. Grever, David M. Lucas. MAPK-mediated immunomodulation in disseminated murine Emu-TCL1 chronic lymphocytic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1029. doi:10.1158/1538-7445.AM2017-1029

Ruptured intracranial aneurysm in patients with osteogenesis imperfecta: 2 familial cases and a systematic review of the literature

OBJECTIVE

Osteogenesis imperfecta is an inherited connective tissue disorder that causes bone fragility. Vascular complications have been described, but only few cases of ruptured intracranial aneurysm have been reported.

MATERIALS AND METHODS

We first described 2 familial cases of ruptured intracranial aneurysm and then conducted a systematic review of the literature.

RESULTS

A mother and her daughter with a typical history of osteogenesis imperfecta presented with subarachnoid hemorrhage, which was related to a posterior communicating artery aneurysm in both cases. The mother had early rebleeding and died. The aneurysm was excluded by coiling in the daughter. Despite occurrence of hydrocephalus and delayed cerebral ischemia, she had an excellent functional outcome. A systematic review of the literature identified seven additional cases. None of the cases were in fact familial. All patients had a previous medical history of multiple fractures. Seven aneurysms were resolved, three by surgical clipping and four by endovascular procedure. No periprocedural complication was reported. One patient died prematurely and 6 experienced good functional outcome.

CONCLUSIONS

We report the first familial cases of aneurysmal subarachnoid hemorrhage in osteogenesis imperfecta patients. Intracranial aneurysms are probably linked to a collagen pathology, which is at the origin of osteogenesis imperfecta. In cases of aneurysmal subarachnoid hemorrhage in an osteogenesis imperfecta family, intracranial aneurysm screenings in the relatives showing osteogenesis imperfecta should be considered.

Re-designing the substrate binding pocket of laccase for enhanced oxidation of sinapic acid

Iterative saturation mutagenesis was performed over six residues delimiting the substrate binding pocket of a high redox potential chimeric laccase with the aim of enhancing its activity over sinapic acid, a lignin-related phenol of industrial interest.

C1-C2 stabilization by Harms arthrodesis: indications, technique, complications and outcomes in a prospective 26-case series

INTRODUCTION

C1-C2 arthrodesis is a surgical challenge due to the proximity of neurovascular structures (vertebral arteries and spinal cord) and the wide range of motion of the joint, hampering bone fusion. A variety of techniques have been successively recommended to reduce anatomic risk and improve results in terms of biomechanical stability and fusion rates. Recently, Harms described a new technique using polyaxial screws in the C1 lateral masses and C2 pedicles.

MATERIAL AND METHOD

The present study reports our experience in a consecutive series of 26 patients operated on by C1-C2 arthrodesis using the Goel and Harms technique, and details technical aspects step by step. Routine systematic immediate postoperative CT and 6-month CT controlled screw positioning and assessed fusion. Follow-up was at least 1 year, except in 2 cases (10 months).

RESULTS

Twenty-six patients with a mean age of 57 years were included. Indications comprised: C2 non-union (n=11), C1-C2 fracture and/or dislocation (n=11), inflammatory pathology (n=2) and tumoral pathology (n=2). The results showed the technique to be reliable (no neurovascular complications and 85% of screws with perfect positioning) and an excellent rate of fusion (100% at 6 months).

CONCLUSION

Anatomic and biomechanical considerations, combined with the present clinical and radiological outcomes, indicate that Goel and Harms fusion is to be considered the first-line attitude of choice for posterior C1-C2 arthrodesis.

LEVEL OF EVIDENCE

Level IV prospective study.

A methodological strategy to analyze and improve the French rainwater harvesting regulation in relation to quality

In 2008, France implemented a regulation framework for rainwater harvesting (RWH). This framework implicitly defines several categories of rainwater quality for different uses through specific technical requirements to be implemented. This paper presents a detailed analysis of these requirements. Then, results concerning the bacteriological and physicochemical water quality from past on-site studies undertaken in France are compared in order to develop a methodological strategy aiming to validate, clarify or invalidate them through future experiments.

Progression of the renal graft: treatment of acute rejection based on a biopsy against a presumptive diagnosis

The aim of this study was to compare the progression of renal grafts following treatment of an acute rejection event based on the histological diagnosis of a graft biopsy compared to a presumptive (clinical and laboratory) diagnosis. A historical cohort was used to study 44 patients undergoing a living haploidentical related donor renal transplant, using a similar immunosuppressive treatment: cyclosporine, azathioprine, and prednisone. Acute rejection events were treated with methylprednisolone (250 mg for 3 to 5 days) based on a histological diagnosis (biopsy group = 14) or on a clinical and laboratory diagnosis (presumptive group = 30), which consisted of an elevation over 20% in plasma creatinine in 24 hours and renal ultrasound or scintigraphy findings. The study demonstrated no significant difference in renal function (plasma creatinine) and other outcomes 2 years following transplantation in both groups. The results show that treatment of acute rejection based on a presumptive diagnosis is not a risk factor for unfavorable outcomes following 2 years of renal transplantation monitoring.

A therapeutic area review of oncology products and players

This article reviews the dynamics of the oncology market and treatment trends and provides strategic guidance to those concerned with new product discovery and development. Cancer is the therapeutic area of highest potential, with an annual market value expected to be in excess of US 40 billion dollars in 2020. The global incidence of cancer cases is forecast to more than double over the next 20 years. Investments in research and development will keep pace with the growing demand for effective treatments, aiming to fulfil the many and often discrete unmet medical needs. Recent breakthroughs promise more successful outcomes, particularly with the advent of more selective chemotherapy and novel therapeutic approaches. Among the latter, a number of angiogenesis inhibitors and monoclonal antibodies (mAbs) should show encouraging levels of efficacy by 2004. Oncology is a complex and high-risk therapeutic area that offers high rewards. It is appropriate for only the stronger or more focused serious players within the pharmaceutical industry. The winners will be the companies with a long-term strategic intent, a credible portfolio and engagement in appropriate alliances, particularly in discovery. The future presents ethical, clinical and commercial challenges, given the wide disparity of therapeutic outcomes among cancer patients around the world. The real success will thus be to treat cancer in innovative ways that benefit everyone and are, in volume and across the life cycle, commercially attractive to the treatment provider.

[Palisading granuloma of the penis: a variant of subcutaneous granuloma annulare]

INTRODUCTION

Subcutaneous granuloma annulare on the penis has only been reported exceptionally.

OBSERVATION

A 41 year-old man presented with four small, asymptomatic nodules on the glans penis. Histological examination of a biopsy revealed a deep palisading granuloma progressing not only around the alcian-blue necrobiosis areas but also around the smooth muscle fibers. The lesion regressed spontaneously after two years of progression.

DISCUSSION

Palisading granuloma of the penis appears to be a most particular clinical form of subcutaneous granuloma annulare. It is characterized by small single or multiple nodules localized on the penis. On histological examination, the granuloma is deep and concentrates around the network of smooth muscle fibers of dartoic origin.

Effects of ammonia and amino acids on the growth and proteolytic activity of three species of rumen bacteria: Prevotella albensis, Butyrivibrio fibrisolvens, and Streptococcus bovis

The addition of increasing physiological concentrations of ammonia or amino acids had distinct effects on the growth and proteolytic activity of Streptococcus bovis JB1, Prevotella albensis, and Butyrivibrio fibrisolvens DSM3071. The growth of S. bovis and B. fibrisolvens was enhanced by NH(3) and AA, and that of P. albensis was reduced compared with a control with protein as the sole source of nitrogen. The proteolytic activity of S. bovis and P. albensis was reduced, but that of B. fibrisolvens was improved. NH(3) seemed to act mainly on the cell-associated fraction of the proteolytic activity, while the action of AA was not specific. In the rumen the proteolytic activity of S. bovis and P. albensis would be optimal at low concentrations of NH(3) or AA (<0.05 and <0.27 g/L respectively). In contrast, B. fibrisolvens would need higher concentrations (0.5 g/L of NH(3) or 2.7 g/L of AA). It can be assumed that these bacteria will grow in different ecological niches.

[Multiple cutaneous reticulohistiocytosis]

BACKGROUND

Multicentric reticulohistiocytosis is a non Langerhans cell histiocytosis. This rare disease is characterized by cutaneous papules and nodules and a destructive polyarthritis; multisystem involvement may occur. Multiple and diffuse cutaneous reticulohistiocytosis have been more rarely reported. We present a case which was distinctive by the existence of multiple cutaneous plaques.

CASE REPORT

A 65-year-old woman presented cutaneous papules and nodules associated with a destructive arthritis affecting the hands. Histological examination of a cutaneous biopsy associated with immunophenotyping and electronic microscopy permitted us to make the diagnosis of multicentric reticulohistiocytosis. The search for visceral involvement or underlying neoplasia was negative. Rapidly, cutaneous aggravation occurred with multiple and diffuse infiltrated plaques on the back, the face, the ears, the thighs and the forearms. The same histological aspect was found for these lesions. Treatment with corticosteroids and cyclophosphamide was successful.

DISCUSSION

This case report is the first one with diffuse cutaneous lesions of multicentric reticulohistiocytosis with aspect of infiltrated plaques. Diffuse cutaneous lesions in multicentric reticulohistiocytosis have been rarely reported with diffuse papules or nodules pattern. A visceral involvement seems to be more frequent for diffuse cutaneous involvement. In all cases, the association of multicentric reticulohistiocytosis with neoplasia in up to 25 p. 100 is of interest. Treatment of multicentric reticulohistiocytosis consists in corticosteroids at the initial phase associated with alkylants agents or methotrexate.

Combination of biomolecular and stable isotope techniques to determine the origin of organic matter used by bacterial communities: application to sediment

Natural isotopic composition is a good tool to trace organic matter in ecosystems. Recent studies used a combination of molecular and stable isotope techniques to determine the origin of the organic carbon used by bacteria in the water column. In our study, we show that this procedure can be used for analysis of sediment bacterial communities with few modifications. In the water column, bacterial recovery is done before DNA extraction. In the sediment, we tested qualitatively and quantitatively a direct and indirect extraction of DNA. The direct extraction was the most efficient. It recovered between 3.1 and 15.8 microg DNA g(-1) dry sediment and the contamination of field samples by eucaryotic DNA was less than 13%. In this preliminary study of the salt marsh ecosystem, the delta(13)C values of DNA (-26 to - 24%) recovered from the sediment were close to the delta(13)C values of halophytic plants (-26.4 and - 25.3%) showing a relationship between plants and microorganisms. Thus, this procedure can be used to trace the flow of carbon through the sediment microbial biomass and to understand the variation of bacterial activity according to the inputs of allocthonous and autochtonous organic matter.

Flavor preferences conditioned by high-fat versus high-carbohydrate diets vary as a function of session length

Intragastric (i.g.) infusions of fat and carbohydrate condition flavor preferences in rats, but different results have been obtained in studies using pure and mixed nutrient infusions. This experiment compared the preference conditioning effects of mixed high-carbohydrate (HC) and high-fat (HF) diet infusions during short-term and long-term sessions. In Experiment 1 food-deprived rats were given one flavored saccharin solution (CS+HC) paired with i.g. infusions of an HC liquid diet, a second flavor (CS+HF) paired with HF diet infusions, and a third flavor (CS-) paired with i.g. water infusions during 30-min one-bottle training sessions. In subsequent two-bottle tests (30 min/day), the rats preferred both CS+s to the CS- and preferred the CS+HC to the CS+HF. In Experiment 2, the same rats were trained and tested with the CSs and paired infusions during 22 h/day sessions with chow available ad lib. Both CS+s were again preferred to the CS-, but now the CS+HF was preferred to the CS+HC. When given additional 30-min choice sessions in Experiment 3 the rats showed no reliable preference for the CS+HC versus CS+HF under food-deprived or ad lib conditions. In Experiment 4, the rats were given 22-h CS+HC versus CS+HF choice sessions every other day. They showed no reliable CS preference during the first 30 min of each session, but reliably preferred the CS+HF during the remaining 21.5 h. These findings indicate that previously reported differences in preferences conditioned by pure versus mixed nutrient infusions are due to training procedures (session length, deprivation state) rather than to the type of nutrient infusions per se. The rats displayed different CS+HF versus CS+HC preferences as a function of test duration even after being given both short- and long-term training. Thus, short-term choice tests do not always predict the long-term intakes and preferences for high-fat and high-carbohydrate foods.