ALBERT

Description: : Skyline is a Windows client application for targeted proteomics method creation and quantitative data analysis. The Skyline document model contains extensive mass spectrometry data from targeted proteomics experiments performed using selected reaction monitoring, parallel reaction monitoring and data-independent and data-dependent acquisition methods. Researchers have developed software tools that perform statistical analysis of the experimental data contained within Skyline documents. The new external tools framework allows researchers to integrate their tools into Skyline without modifying the Skyline codebase. Installed tools provide point-and-click access to downstream statistical analysis of data processed in Skyline. The framework also specifies a uniform interface to format tools for installation into Skyline. Tool developers can now easily share their tools with proteomics researchers using Skyline. Availability and implementation: Skyline is available as a single-click self-updating web installation at http://skyline.maccosslab.org . This Web site also provides access to installable external tools and documentation. Contact: brendanx@u.washington.edu Supplementary information: Supplementary data are available at Bioinformatics online.

Description: The class II transactivator (CIITA) is essential for the expression of major histocompatibility complex class II (MHC-II) genes; however, the role of CIITA in gene regulation outside of MHC-II biology is not fully understood. To comprehensively map CIITA-bound loci, ChIP-seq was performed in the human B lymphoblastoma cell line Raji. CIITA bound 480 sites, and was significantly enriched at active promoters and enhancers. The complexity of CIITA transcriptional regulation of target genes was analyzed using a combination of CIITA -null cells, including a novel cell line created using CRISPR/Cas9 tools. MHC-II genes and a few novel genes were regulated by CIITA; however, most other genes demonstrated either diminished or no changes in the absence of CIITA. Nearly all CIITA-bound sites were within regions containing accessible chromatin, and CIITA's presence at these sites was associated with increased histone H3K27 acetylation, suggesting that CIITA's role at these non-regulated loci may be to poise the region for subsequent regulation. Computational genome-wide modeling of the CIITA bound XY box motifs provided constraints for sequences associated with CIITA-mediated gene regulation versus binding. These data therefore define the CIITA regulome in B cells and establish sequence specificities that predict activity for an essential regulator of the adaptive immune response.

Description: Introduction: BCMA is a tumor necrosis factor (TNF) receptor superfamily transmembrane glycoprotein essential for the maturation and survival of plasma cells. CC-93269 is an asymmetric 2-arm humanized IgG TCE that binds bivalently to BCMA and monovalently to CD3ε in a 2+1 format (Seckinger A, et al. Cancer Cell. 2017;31:396-410). The CC-93269-mediated interaction between T cells and BCMA-expressing myeloma cells induces T cell receptor/CD3 crosslinking leading to T cell activation, and release of proinflammatory cytokines and cytolytic enzymes, resulting in myeloma cell death. In preclinical studies with CC-93269 and related molecules, 2+1 BCMA TCEs induced tumor regression in animal models and promoted myeloma cell death in primary pt myeloma cells. Here we report interim results from a phase 1 dose-finding study (CC-93269-MM-001; NCT03486067) evaluating CC-93269 in pts with RRMM. Methods: Eligible pts had RRMM and had received ≥ 3 prior regimens without prior BCMA-directed therapy. In dose escalation, CC-93269 was administered intravenously over 2 hours on Days 1, 8, 15, and 22 for Cycles 1-3; Days 1 and 15 for Cycles 4-6; and on Day 1 for Cycle 7 and beyond, all in 28-day cycles. Dose escalation involved 2 stages: in stage 1, CC-93269 was given in fixed doses; in stage 2, pts received a fixed first dose on Cycle 1 Day 1, followed by intrapatient dose escalation on Cycle 1 Day 8. Primary objectives were to assess the safety and tolerability of CC-93269 and define the maximum tolerated dose (MTD), non-tolerated dose (NTD), and/or recommended phase 2 dose (RP2D). Minimal residual disease (MRD) was assessed after clinical response in pt bone marrow aspirate samples by Next Generation Flow using the EuroFlow panel. MRD negativity was reported only if a minimum sensitivity of 〈 1 tumor cell in 105 nucleated cells was achieved. Results: As of May 24, 2019, 19 pts had received CC-93269. Median age was 64 years (range 51-78), with a median of 6.2 years (range 1.4-13.9) since initial diagnosis. The median number of prior regimens was 6 (range 3-12) and included treatment with autologous stem cell transplantation (73.7%), allogenic stem cell transplantation (10.5%), lenalidomide (100%), pomalidomide (84.2%), bortezomib (100%), carfilzomib (84.2%), and daratumumab (DARA; 94.7%). All pts had MM refractory to their last line of therapy, with 16 (88.9%) refractory to DARA, 17 (89.5%) to their last proteasome inhibitor, and 16 (84.2%) to their last immunomodulatory agent. CC-93269 doses ranged from 0.15 to 10 mg; median duration of treatment was 14.6 weeks (range 1.6-32.0) with pts receiving a median of 4 cycles (range 1-8). Grade 3-4 treatment-emergent adverse events were reported in 15 (78.9%) pts and included 10 (52.6%) pts with neutropenia, 8 (42.1%) with anemia, 5 (26.3%) with infections, and 4 (21.1%) with thrombocytopenia. No pt required dose modifications. Cytokine release syndrome (CRS) was reported in 17 (89.5%) pts, the majority of whom reported a maximum grade 1 (n = 11 [57.9%]) or grade 2 (n = 5 [26.3%]), and occurred most frequently with the first or second dose (n = 22 of 27 events [81.5%]). CRS prophylaxis was implemented with dexamethasone for first dose and dose increases in pts receiving ≥ 6 mg. Of 27 CRS events, 8 (29.6%) were managed with dexamethasone and 10 (37.0%) with tocilizumab. One pt receiving 6 mg CC-93269 as first dose and 10 mg on Cycle 1 Day 8 died on study in the setting of CRS, with a potential infection as a contributing factor. Dose-related pharmacodynamic activity, including peripheral blood immune cell redistribution and transient release of pro- and anti-inflammatory cytokines, was observed in pts. Of the 12 pts treated with ≥ 6 mg CC-93269 in Cycle 1, 10 pts achieved a partial response (PR) or better (overall response rate; 83.3%), including 7 (58.3%) with a very good partial response (VGPR) or better and 4 (33.3%) with a stringent complete response (sCR) (Table); 9 (75.0%) pts achieved MRD negativity. The median time to response was 4.2 weeks (range 4.0-13.1), and 10 of 10 responses were ongoing with follow-up ranging from 2.1 to 4.7 months. The NTD, MTD, and RP2D have not yet been reached. Conclusions: CC-93269, a 2+1 BCMA TCE, shows a manageable safety profile and promising efficacy, including MRD-negative sCRs, in pts with heavily pretreated RRMM. The study continues to enroll in the dose escalation phase. Updated safety and efficacy data will be presented at the meeting. Disclosures Costa: Fujimoto Pharmaceutical Corporation Japan: Other: Advisor; Karyopharm: Consultancy; Abbvie: Consultancy; Sanofi: Consultancy, Honoraria, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau. Wong:Genentech: Research Funding; Janssen: Research Funding; Celgene Corporation: Research Funding; Fortis: Research Funding; Juno: Research Funding. Bermúdez:MSD: Consultancy, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Fresenius: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. de la Rubia:AMGEN: Consultancy; Celgene Corporation: Consultancy; AbbVie: Consultancy; Takeda: Consultancy; Janssen: Consultancy. Mateos:Pharmamar: Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria; EDO: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Ocio:BMS: Honoraria; Sanofi: Research Funding; Mundipharma: Research Funding; Takeda: Consultancy, Honoraria; Seattle Genetics: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; Array Pharmaceuticals: Research Funding; Pharmamar: Consultancy; Novartis: Consultancy, Honoraria; AbbVie: Consultancy; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria. Rodríguez-Otero:Celgene Corporation: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria; Takeda: Consultancy; BMS: Honoraria; Kite Pharma: Consultancy. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria. Li:Celgene Corporation: Employment, Equity Ownership. Sarmiento:Celgene Corporation: Employment. Lardelli:Celgene Corporation: Employment, Equity Ownership. Gaudy:Celgene Corporation: Employment, Equity Ownership. Boss:Celgene Corporation: Employment, Equity Ownership. Kelly:Celgene Corporation: Employment. Burgess:University of California: Other: Volunteer clinical faculty, without salary, Patents & Royalties: Patent - T315A and F317I mutations of BCR-ABL kinase domain; Celgene Corporation: Employment, Equity Ownership, Patents & Royalties: Patent - CD47 antibodies and methods of use thereof. Hege:Celgene Corporation: Employment, Equity Ownership, Patents & Royalties; Arcus Biosciences: Membership on an entity's Board of Directors or advisory committees; Society for Immunotherapy of Cancer: Membership on an entity's Board of Directors or advisory committees; Mersana Therapuetics: Membership on an entity's Board of Directors or advisory committees. Bensinger:Amgen, Celgene: Other: Personal Fees, Research Funding, Speakers Bureau; Takeda, Janssen: Speakers Bureau; Sanofi, Seattle Genetics, Merck, Karyopharm: Other: Grant.

Description: Background: Loss of immune surveillance, mediated through immune checkpoint (ICP) interactions, is thought to be a key step in the development of cancers including AML and HR-MDS. AZA is a standard therapy for pts with AML who are unfit for IC and for pts with HR-MDS. AZA can promote immune recognition of tumor cells and potentially increase expression of ICP molecules, which can mediate resistance to AZA. As myeloid cell lines and samples from pts treated with hypomethylating agents demonstrated up-regulation of PD-L1 expression, blockade of the PD-L1 ICP with durva in combination with AZA may enhance antitumor activity and improve clinical outcomes. Here, we report the final results from a large phase 2 study evaluating the efficacy and safety of AZA+durva vs. AZA alone in pts with HR-MDS or AML (NCT02775903). Methods: This randomized, open-label, international, multicenter study enrolled untreated pts in 2 cohorts: 1) MDS (aged ≥18 years; IPSS-R intermediate, high, and very high) and 2) older AML pts (aged ≥65 years) who were ineligible for IC. All pts had ECOG performance status 0-2 and were separately randomized (1:1) to receive SC AZA 75 mg/m2 Days 1-7 and durva 1500 mg IV on Day 1 Q4W (Arm A) or AZA alone (Arm B) and stratified according to cytogenetic risk (MDS, very good/good/intermediate vs. poor/very poor; AML, intermediate vs. poor). Treatment was planned to continue until progression or unacceptable toxicity. Disease status was evaluated every third treatment cycle. Primary MDS endpoints included overall response rate (ORR, defined as complete remission [CR], marrow [m]CR, partial response [PR], or hematologic improvement [HI]) based on IWG 2006 response criteria, while for AML ORR was defined as CR or CR with incomplete blood recovery (CRi) based on modified IWG 2003 response criteria. Secondary endpoints included PFS, OS, and safety. Peripheral blood samples were collected to assess changes in DNA methylation using the EPIC methylation array (Illumina). Bone marrow (BM) aspirates were obtained for quantitation of PD-L1 surface expression by flow cytometry and values are reported as molecules of equivalent soluble fluorochrome. Results: A total of 213 pts, 84 with MDS (each arm, n=42) and 129 with AML (Arm A, n=64; Arm B, n=65) were randomized. As of October 31, 2018, 32 pts (MDS, n=14; AML, n=18) continued to receive trial treatment while 181 (MDS, n=70; AML, n=111) had discontinued. Baseline demographics and disease characteristics were generally balanced across treatment groups in both cohorts. Median number of treatment cycles for AML Arm A vs. B, 6.5 vs. 6.7; for MDS Arm A vs. B, 7.9 vs. 7.0. No statistically significant differences in ORR between treatment arms were observed in either cohort (Tables 1 and 2). In MDS Arm A vs. B, median OS was 11.6 vs. 16.7 months (mo) and PFS was 8.7 vs. 8.6 mo. In the AML cohort, median OS was 13.0 vs. 14.4 mo and PFS was 8.1 vs. 7.2 mo. Caution should be used when interpreting results because 〉50% of patients were censored. The most frequent TEAEs (≥15%) were hematologic and GI toxicity. In the MDS and AML cohorts, 7 and 17, respectively, immune-mediated AEs were observed; all were treated and resolved. AZA induced similar trends in global hypomethylation, along with focal hypomethylation of PD-L1 and PD-L2 gene loci, at the end of treatment cycle 1 in all treatment groups and cohorts. Mean PD-L1 surface expression in BM immune cells at baseline was highest in monocytes (MDS=1,425; AML=1,536), followed by granulocytes (MDS=550; AML=758) and myeloid blasts (MDS=532; AML=735). Increased surface expression of PD-L1, but not PD-L2, was observed at the end of treatment cycle 3 on BM granulocytes and monocytes from MDS pts and on BM monocytes from AML pts, but no increase was detected on myeloid blasts. Conclusions: To our knowledge, this is the first large randomized trial of AZA with or without ICP blockade in older unfit AML and HR-MDS pts reported to date. No clinically meaningful difference in efficacy was observed between treatments for either cohort. No new safety signals or potential overlapping risks were identified with the combination. While the hypomethylating activity of AZA on PD-L1 gene was confirmed, no treatment-mediated induction of PD-L1 surface expression was observed on myeloid blasts. Disclosures Zeidan: Acceleron Pharma: Consultancy, Honoraria, Research Funding; Celgene Corporation: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Otsuka: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Medimmune/AstraZeneca: Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Research Funding; Trovagene: Consultancy, Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Research Funding; Jazz: Honoraria; Ariad: Honoraria; Agios: Honoraria; Novartis: Honoraria; Astellas: Honoraria; Daiichi Sankyo: Honoraria; Cardinal Health: Honoraria; Seattle Genetics: Honoraria; BeyondSpring: Honoraria. Voso:Novartis: Speakers Bureau; Celgene: Research Funding, Speakers Bureau. Taussig:Celgene: Research Funding. Boss:Celgene Corporation: Employment, Equity Ownership. Copeland:Celgene Corporation: Employment, Equity Ownership. Gray:Celgene Corporation: Employment, Equity Ownership. Previtali:Celgene Corporation: Employment, Equity Ownership. O'Connor:Celgene Corporation: Employment, Equity Ownership. Rose:Celgene Corporation: Employment, Equity Ownership. Beach:Celgene Corporation: Employment, Equity Ownership. OffLabel Disclosure: Durvalumab is a PD-L1 blocking antibody indicated for the treatment of patients with 1) locally advanced or metastatic urothelial carcinoma who have disease progression during or following platinum-containing chemotherapy, or who have disease progression within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy, or 2) unresectable, stage 3 NSCLC whose disease has not progressed following concurrent platinum-based chemotherapy and radiation therapy.

Description: Adenosine dialdehyde and nitrous oxide, specific S-adeno- sylhomocysteine hydrolase and methionine synthetase inhibitors, respectively, induced differentiation of the human promyelocytic cell line HL-60. Their effect did not appear to be mediated through changes in transmethylation or decreased S-adenosylmethionine synthesis because (1) there was little correlation between the concentrations of adenosine dialdehyde that induced differentiation and those that changed the ratio of the intracellular concentrations of S- adenosylmethionine to S-adenosylhomocysteine, and (2) inhibition of methionine adenosyltransferase by cycloleucine did not induce differentiation. The differentiation induced by adenosine dialdehyde was prevented by homocysteine and that by nitrous oxide was inversely related to the medium methionine concentration. This suggested that differentiation was secondary to decreased methionine synthesis.

Description: Identification of tumor-associated antigens (TAA) has resulted in the development of therapeutic vaccines for the treatment of cancer. We applied an integrated functional genomics approach to identify TAA in malignant tissues of patients with renal cell carcinoma (RCC). A comparative DNA chip analysis of tumor and the corresponding non-malignant tissue from patients with RCC followed by sequencing of peptides bound to the HLA-class I molecules by mass spectrometry was applied to identify novel TAA in RCC. To confirm the immunogenicity of identified epitopes cytotoxic T lymphocytes (CTL) were generated using dendritic cells (DC). Utilizing this approach, two peptides derived from RGS5 binding to either HLA-A*02 or 03 were identified. The key function of regulators of G protein-signalling (RGS) is to bind to G protein α subunits and to stimulate their intrinsic GTPase activity. The hydrolysis of guanosine triphosphate (GTP) to guanosine diphosphate (GDP) thereby is accelerated and the inactive heterotrimer more rapidly restored. Thus, RGS proteins inhibit the biological activity of G proteins. Interestingly, it was recently shown that RGS5 is overexpressed in pericytes of newly developing tumor vessels, indicating that RGS5 plays an important role during tumor angiogenesis. Using RT-PCR analysis we found that RGS5 is expressed on a broad variety of tumor cells including RCC, colorectal, breast and ovarian cancer, malignant melanoma and multiple myeloma as well as in acute and chronic leukemias making this protein an interesting candidate for the development of vaccination strategies to target the tumor cells and the tumor vessels. CTL that were induced using the RGS5 peptides lysed autologous DC pulsed with the cognate peptide or transfected with in vitro transcribed RGS5 RNA as well as HLA-matched tumor cell lines. The specificity and HLA restriction was confirmed using blocking monoclonal antibodies and in cold-target inhibition assays. We next utilized DC transfected with RGS5 RNA to generate specific CTL. Using this approach we confirmed the processing and presentation of the identified peptides by malignant cells. These CTL lysed tumor cells in an antigen specific manner while sparing non-malignant cells. To analyze the induction of RGS5 specific CTL in an autologous setting in patients with malignant diseases, we used blood samples from a patient with acute myeloid leukemia (AML) in complete remission after chemotherapy and were able to generate specific CTL capable of recognizing autologous AML blasts while sparing non-malignant cells. Our results demonstrate that RGS5 is a novel tumor rejection antigen expressed in a wide range of malignancies that can be applied to target malignant cells and tumor angiogenesis.

Description: Recent retrospective studies demonstrated similar overall survival (OS) and relapse rate after allogeneic HCT using matched unrelated or haplo-identical donors. However, differences in graft versus host disease (GVHD) prevention protocols using ATG or PTCY may have influenced the results. In addition, there is little knowledge about immune reconstitution after PTCY compared to ATG. We examined the outcomes of 73 consecutive patients who received allogeneic HCT from 5/2015 to 4/2019 (39 Haplo, 34 MUD). Patient's Characteristics shown in table-1. The two groups matched except for donor age, CD34 dose infused and race. Conditioning regimens shown in table-1. MUD recipients received GVHD prophylaxis with Tacrolimus/ Mycophenolate (Tacro/MMF) in addition to ATG (24 Patients) or PTCY (10 Patients) while Haploidentical patient received Tacro/MMF with PTCY. A panel of immune reconstitution markers collected at day 100 post- transplant for CD3, CD4, CD8, Activated T cell ( HLA- DR3+ CD3+)and NK cells ( CD56+) was obtained for 29 MUD and 28 Haploidentical recipients. We observed pronounced proliferation and recovery in all T cell subsets in Haploidentical patients compared to MUD patients at day 100 as shown in Fig-1. This robust T cell recovery in Haploidentical transplant patients with PTCY was statistically significant for CD3, CD4 and CD8. When Immune reconstitution for Haploidentical patients compared to MUD patients who received PTCY, it maintained its robust effect on T cell proliferation (Fig-2) although it did not reach statistical significance. The overall survival at one-year with median duration of follow up of 22.6 months was 61.5% and 82.3% for Haploidentical and MUD recipients respectively; P=0.14. There were 15 deaths during the first year in the Haploidentical patients (3 = relapse, 5 = severe cytokine release syndrome (CRS), 1=Veno-occlusive disease, 3= infection, 2=GVHD and 1 = primary graft failure). In contrast there were only six deaths in MUD patients (2= relapse, 3= GVHD and 1= infection). There was no deaths in MUD PTCY patients in the first year. There was no primary graft failure in either arm, however secondary graft failure occurred in 2 Haploidentical and 1 MUD patients. Median time to engraftment was 18 days for Haploidentical (range, 12-57) and 11.6 days for MUD (range, 10-18). Acute GVHD grade 2-4 developed in 35% in MUD and 23% in Haploidentical patients. Conclusions: We found robust early immune recovery after Haploidentical HCT compared to MUD HCT. The degree of HLA mismatch with Haploidentical HCT and antigen presentation may have contributed to pronounced T cell proliferation as the same effects was not observed in MUD HCT with PTCY. Despite the early recovery of T cells after Haploidentical HCT the overall survival did not exceed the overall survival with MUD HCT. Severe CRS contributed to the increased mortality seen in Haploidentical HCT patients. Further strategies are needed to decrease treatment related mortality with Haploidentical HCT. Disclosures No relevant conflicts of interest to declare.

Description: Multiple studies have examined the impact of the intensity of conditioning regimens on myeloablation and the risk of relapse after HCT. In contrast to adoptive cell transfer and Chimeric-Antigen Receptor (CAR) T-Cell therapy, there is limited, if any knowledge that has addressed the impact of intensity of lymphodepletion on relapse after HID HCT. We hypothesize that enhanced lympho-depletion would create an enhanced host immunogenic microenvironment that would foster potent donor T cell expansion and alloreactivity after T-cell replete peripheral blood HID HCT.1,2 We utilized an intensified lympho-depleting conditioning regimen with Fludarabine (Flu) 150 mg/m2, Melphalan (Mel) 140 mg/m2 and Cyclophosphamide (CY) 29 mg/m2 prior to T-cell replete peripheral blood HID HCT to treat 15 consecutive patients with high risk hematological malignancies between July 2015 and June 2017. The intensity of lymphodepletion was confirmed in 12 evaluable patients at day (0) by complete absence of lymphocytes in peripheral smear. In contrast, myeloid elements were detected in 7/12 patients suggesting more intense lympho-depletion than myeloablation. All Patients received graft versus host disease prophylaxis with Tacrolimus/Mycophenolate starting at day +5 and Cyclophosphamide 50 mg/Kg on day +3 & +4. Mycophenolate continued for 30 days and Tacrolimus stopped at Day 180 without taper. Patient characteristics are shown in Table 1. More than half the patients (n=8 Pts) had relapsed/refractory or progressive disease at time of transplant. The median duration of follow up for survivors is 29 months (range 13-37). Chimerism studies were performed at day +30 and +100 post-transplant by variable number tandem repeat PCR analysis of peripheral blood (PB) and bone marrow (BM). All patients engrafted and achieved 100% Chimerism in BM and PB ( CD3, CD33 & CD56) by day 100 except for 1 patient who died at day +25 prior to engraftment. Median time to neutrophil engraftment was 21 days (range 12-57). All patients with refractory/relapsed disease achieved complete remission post-transplant except for 1 patient who died from transplant complications prior to engraftment. The day 100, 1 year & 2 year overall survival was 93%, 73% & 66% respectively. We observed very low cumulative incidence of relapse of 7% at day 100, 1 and 2 years post-HCT (only 1/15 patients). Treatment related mortality (TRM) was 6%, 20% and 27% at day 100, 1 and 2 years respectively (4/15 patients). Severe Cytokine Release Syndrome (CRS), grade 4 by Lee Criteria occurred in 4 patients, all of them have died at day 25, 258, 288 and 540 post HCT. Three of the four patients with severe CRS had refractory relapsed disease at time of HCT. Grade II-IV acute GVHD developed in 4/15 patients (27%), 2 of whom had grade III-IV by day +180. Chronic extensive GVHD developed in 7 patients (46%), which required definitive therapy (Prednisone/Rituximab/Extracorporeal Photopheresis). At 2 years post HCT, only 1/7 patients remain with extensive chronic GVHD requiring active treatment, 3 patients have quiescent disease and 3 patients have died. Post -transplant immune reconstitution panels were obtained at day 60, 120, 180 and 1 year in 14, 13, 13 and 10 evaluable patients respectively as shown in Fig 1. We observed early recovery in all T-cell subsets at day 60 with activated T cells (CD3+, HLA-Dr+) being most pronounced. While the early proliferation in activated T cells declined through the first-year post transplant, NK cells and CD4 maintained their early recovery through the first year. There was initial decline in the number of B cells at day 120 which gradually recovered by 1 year. Conclusion: Enhanced lymphodepletion prior to peripheral blood HID HCT may enhance early T cell proliferation alloreactivity and immune reconstitution. There was low relapse rate at the expense of high TRM in patients who developed grade IV CRS. Future strategies directed at decreasing disease burden prior to lympho-depletion and improved management of severe CRS in high risk patients are needed to harness the benefits of the observed low relapse rate. 1. Beavis et al, Reprogramming the tumor microenvironment to enhance adoptive cellular therapy. Semin Immunol. 2016 Feb;28(1):64-72. 2. Lu X, Ding ZC, Cao Y, Liu C, Habtetsion T, Yu M, Lemos H, Mellor AL, et al. Alkylating agent melphalan augments the efficacy of adoptive immunotherapy using tumor-specific CD4+ T cells.J Immunol. 2015 Feb 15;194(4):2011-21. Disclosures No relevant conflicts of interest to declare.

Description: Key Points BCL6 and BACH2 cooperatively regulate GC B-cell development. The cooperative action of BCL6 and BACH2 is through both transcriptional and biochemical mechanisms.

Description: Adenosine dialdehyde and nitrous oxide, specific S-adeno- sylhomocysteine hydrolase and methionine synthetase inhibitors, respectively, induced differentiation of the human promyelocytic cell line HL-60. Their effect did not appear to be mediated through changes in transmethylation or decreased S-adenosylmethionine synthesis because (1) there was little correlation between the concentrations of adenosine dialdehyde that induced differentiation and those that changed the ratio of the intracellular concentrations of S- adenosylmethionine to S-adenosylhomocysteine, and (2) inhibition of methionine adenosyltransferase by cycloleucine did not induce differentiation. The differentiation induced by adenosine dialdehyde was prevented by homocysteine and that by nitrous oxide was inversely related to the medium methionine concentration. This suggested that differentiation was secondary to decreased methionine synthesis.