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Sandeep Dave and colleagues report exome sequencing of 59 Burkitt lymphomas. They report recurrent mutations in many genes, including ID3 , MYC , GNA13 , RET , PIK3R1 , NOTCH1 and the SWI/SNF genes ARID1A and SMARCA4 . Burkitt lymphoma is characterized by deregulation of MYC , but the contribution of other genetic mutations to the disease is largely unknown. Here, we describe the first completely sequenced genome from a Burkitt lymphoma tumor and germline DNA from the same affected individual. We further sequenced the exomes of 59 Burkitt lymphoma tumors and compared them to sequenced exomes from 94 diffuse large B-cell lymphoma (DLBCL) tumors. We identified 70 genes that were recurrently mutated in Burkitt lymphomas, including ID3 , GNA13 , RET , PIK3R1 and the SWI/SNF genes ARID1A and SMARCA4 . Our data implicate a number of genes in cancer for the first time, including CCT6B , SALL3 , FTCD and PC . ID3 mutations occurred in 34% of Burkitt lymphomas and not in DLBCLs. We show experimentally that ID3 mutations promote cell cycle progression and proliferation. Our work thus elucidates commonly occurring gene-coding mutations in Burkitt lymphoma and implicates ID3 as a new tumor suppressor gene.

Diffuse large B-cell lymphoma (DLBCL) is the most common form of lymphoma in adults. The disease exhibits a striking heterogeneity in gene expression profiles and clinical outcomes, but its genetic causes remain to be fully defined. Through whole genome and exome sequencing, we characterized the genetic diversity of DLBCL. In all, we sequenced 73 DLBCL primary tumors (34 with matched normal DNA). Separately, we sequenced the exomes of 21 DLBCL cell lines. We identified 322 DLBCL cancer genes that were recurrently mutated in primary DLBCLs. We identified recurrent mutations implicating a number of known and not previously identified genes and pathways in DLBCL including those related to chromatin modification (ARID1A and MEF2B), NF-κB (CARD11 and TNFAIP3), PI3 kinase (PIK3CD , PIK3R1 , and MTOR), B-cell lineage (IRF8 , POU2F2 , and GNA13), and WNT signaling (WIF1). We also experimentally validated a mutation in PIK3CD , a gene not previously implicated in lymphomas. The patterns of mutation demonstrated a classic long tail distribution with substantial variation of mutated genes from patient to patient and also between published studies. Thus, our study reveals the tremendous genetic heterogeneity that underlies lymphomas and highlights the need for personalized medicine approaches to treating these patients.

BackgroundTCM are aggressive diseases with poor outcomes. Translating the CAR T-cell therapy success from B-cell diseases to TCM has proven challenging. CD4 is an attractive therapeutic target, owing to its restricted expression on normal tissues. In this first-in-human phase I study, we investigate the autologous third generation CD4-redirected CAR T-cell safety, tolerability, manufacturing feasibility, trafficking and preliminary efficacy in patients with R/R CD4+ TCM who failed standard therapies.MethodsThe investigational construct is engineered with a single-chain variable fragment (ScFV) and dual co-stimulators (CD28; 4–1BB), fused to CD3zeta and CD8 leader sequence, packaged in lentivirus and transducer into T-cells. Patients received conditioning therapy with fludarabine and cyclophosphamide. CD4CAR product is administered in a 3+3 dose-escalation scheme. Dose-limiting toxicities (DLT) were monitored during the initial 42-days post-treatment. Treatment-emergent adverse events (AE) were graded by CTCAE v5.0ResultsThree patients with median age of 63 years (range, 18–68) were enrolled and treated at DL1 (2.0x10^5/kg), including 2 (66%) women and 2 (66%) African-American. Median number of prior therapies was 3 (range, 2–4) (figure 1). AEs included grade 3–4 hematologic toxicity in 3 (100%) patients, all present before enrollment. There was no protocol defined DLTs. All grade ≥3 lymphopenia reverted to grade 2 by day 30 and no related infections occurred between CAR infusion and hematopoietic stem cell transplantation (HSCT). Since infusion, the CAR T-cells percentage in peripheral blood had continued to expand. CD4CAR T-cells were detectable in all patients for at least 28 days post-infusion, meeting the primary endpoint, and on D111 in one patient. CD4CAR expansion was reflected on by a decrease in CD4/CD8 ratio and flow cytometry using ScFV Fab2 specific antibodies (figure 2). Cytokine response analysis CD4CAR was associated with variable but significant production that seems to correlate with clinical responses (figure 3 of responders; More data at meeting). No cytokine-mediated organ toxicities were observed. Bone marrow and peripheral blood flow cytometry confirmed complete remission (CR) in 2 patients at day 30 (PTCL and T-ALL). Patient 3 (mycosis fungoides) achieved hematological CR with stable skin lesions. Post-treatment day 30 skin biopsy demonstrated persistent disease with marked loss of CD4.ConclusionsCD4CAR T-cell therapy is feasible in patients with R/R CD4+ TCM. 2/3 patients achieved CR and the third achieved hematological CR with stable skin disease. Toxicities were manageable without DLT upon completion of cohort 1. The cytokine response suggests immune activation and tumor recognition by CD4CAR T-cells. Dose escalation will proceed. NCT03829540Ethics ApprovalIRB approved at IU, Stony Brook University and University of Louisville.Protocol number CTO-IUSCCC-ICG122–101DSMC approved latest reportAll participants provided a signed informed consent before enrollment; the study and its procedures are conducted abiding by all ethical principles according to the declaration of HelsinkiAbstract 683 Figure 1Abstract 683 Figure 2Abstract 683 Figure 3

Cold agglutinin-mediated autoimmune haemolytic anaemia is associated with the development of autoantibodies that can agglutinate red blood cells at cold temperatures. While primary cold agglutinin disease is an idiopathic lymphoproliferative disorder, secondary cold agglutinin syndrome (CAS) complicates other diseases such as infections, autoimmune diseases and cancers, mostly low-grade lymphomas. Early recognition, treatment of CAS and treatment of its associated underlying diseases are crucial to a successful outcome. We report a case of CAS in a setting of diffuse large B cell lymphoma, in which the treatment course was complicated by worsened anaemia due to chemotherapy-induced myelosuppression. We reviewed previously reported cases and discussed diagnosis and treatment strategies, including novel complement inhibitors, as potential future therapy.

Primary central nervous system lymphomas are rare neoplasms characterized by a dismal prognosis relative to other extranodal lymphomas. Approximately 98% of primary central nervous system lymphomas are of B-cell origin, and most belong to the diffuse large B-cell type. Recently, diffuse large B-cell lymphomas have been subcategorized into germinal center and nongerminal center types based on gene expression profiles and immunohistochemical expression of CD10, Bcl-6, and MUM1. Studies have shown that the overall survival rate of the germinal center group is better than that of the nongerminal center lymphomas. In this study, 31 cases of primary central nervous system lymphomas of the diffuse large B-cell type were retrieved, reviewed, and immunostained for CD10, Bcl-6, MUM1, and Ki-67. Subclassification was carried out as described earlier, where CD10 and/or Bcl-6 positivity and negativity for MUM1 were considered characteristic of germinal center subtype and the opposite expression of nongerminal center subtype. Furthermore, the proliferative activity was semiquantitatively assessed using percent positive cells staining with Ki-67. Of the 31 cases examined, 26 (84%) were found to belong to the nongerminal center type. The Ki-67 index in these 26 cases ranged from 30 to 90% (mean, 69%). Five cases were categorized as the germinal center subtype. They had an Ki-67 index between 70 and 90% (mean, 78%). Interestingly, none of our patients were known to be HIV positive. One patient had a 10-year history of orthotopic liver transplant. We also performed fluorescence in situ hybridization analysis on formalin-fixed material and found that 38% of the cases where tissue was available had abnormalities of MYC/IGH and/or IGH/BCL2 . We conclude that most primary central nervous system diffuse large B-cell lymphomas are of the nongerminal center origin. Regardless of the germinal center status, all cases showed a high proliferative rate. A statistically significant difference in the overall survival between the two groups was not seen.

The World Health Organization criteria for diagnosing chronic myelomonocytic leukemia (CMML) are largely based on findings observed in the peripheral blood and bone marrow aspirate. A specific diagnostic role for the bone marrow biopsy has not been adequately explored. We examined whether bone marrow biopsy supplemented by immunohistochemistry may be helpful in distinguishing CMML from cases of chronic myelogenous leukemia and atypical chronic myeloid leukemia (aCML). We immunostained 25 cases of CMML with paraffin reactive antibodies which included CD68 (KP1), CD68R (PG-M1), and CD163, and compared the results with those observed in six cases of chronic myelogenous leukemia and in three cases of atypical CML. In addition, we examined whether CD34 immunohistochemistry could be useful in separating cases of CMML with less than 10% blasts (type-1) from cases of CMML with blasts accounting for 10–19% (type-2), and cases of CMML in acute transformation to acute myeloid leukemia (blasts≥20%). The presence of nodules of plasmacytoid monocytes was investigated by CD123 staining. CD42b was used to highlight abnormal megakaryocytes. Our results demonstrate significant differences between the groups. CD34 analysis allowed separating CMML type-1 from type-2 and the former from CMML in acute transformation. CD123-positive plasmacytoid monocyte nodules were found only in CMML and not in the other two disease groups. Overlap between CMML and the other two groups were observed with CD68 immunostaining. CD68R was more restricted to bone marrow macrophages and monocytes than CD68, but the differences between CMML and chronic myelogenous leukemia or atypical CML were still not significant. Although CD42b immunostaining facilitated the detection of dwarf megakaryocytes often present in CMML, the distinction between those and the small forms seen in chronic myelogenous leukemia was still problematic.

Objectives: This session of the Society for Hematopathology/European Association for Haematopathology workshop focused on disease progression in myeloproliferative neoplasms (MPNs). Methods: The session included typical and unusual presentations of chronic myelogenous leukemia (CML), BCR-ABL1 positive; Philadelphia chromosome–negative (Ph-neg) MPNs; and mastocytosis. Results: Cases of CML illustrated various manifestations of progression, with emphasis on criteria defining stages of the disease. Issues were discussed related to the patterns of recurrence in patients receiving tyrosine kinase inhibitor therapy, including leukemic transformation occurring in a Ph-neg clone. Ph-neg MPN cases highlighted diagnostic approaches used to establish accelerated and blast phases, including cases with significant myelofibrosis and when an adequate bone marrow aspirate smear is not available. The session also included rare cases of aggressive mastocytosis. Conclusions: There was agreement that a definitive diagnosis can be challenging in the absence of documented review of prior diagnostic material and clinical history.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, hyperinflammatory syndrome characterized by clinical signs and symptoms of extreme inflammation. In adults, HLH is typically a complication of infections, autoimmune diseases, and malignancies. While the disease is often fatal, classic management of HLH revolves around early diagnosis and initiation of protocolized therapy. We present a case of a previously healthy 56-year-old female who developed distributive shock requiring intubation, vasopressors, and continuous venovenous hemofiltration. In the setting of multiple infectious syndromes, severe cytopenias, and rising direct hyperbilirubinemia, her diagnosis of HLH was confirmed. Therapy was initiated with dexamethasone and two doses of reduced-intensity etoposide based on the patient’s clinical course. Over the next few weeks, she continued to improve on dexamethasone monotherapy and has maintained remission up to the present with complete resolution of her cytopenias and return of baseline renal function. Our case highlights the variability in the management of probable infection-associated HLH (IHLH) with a good patient outcome. We demonstrate the potential to treat IHLH with partial protocols and minimal chemotherapeutics.