Outcomes of Human Leukocyte Antigen-Matched Related Donor and Haploidentical Allogeneic Hematopoietic Cell Transplantation Recipients by Immune Profiles of Recipients and Donors.

Haploidentical (Haplo) allogeneic HCTs (alloHCT) have been used more frequently over the last decade as survival is similar to HLA-matched related donor (MRD) alloHCTs. We aimed to identify donor and recipient immune signatures before alloHCT that are associated with clinically meaningful outcomes in MRD vs Haplo alloHCT recipients. This retrospective cohort study of 165 MRD (n = 132) and Haplo (n = 33) alloHCT recipients and their related donors between 2007-2019 with paired peripheral blood samples immunophenotyped for T-cell, B-cell, NK cell and dendritic cell (DC) subsets. Immune cells were quantified before alloHCT in donors and recipients; calculations of immune cell ratios were classified as high, intermediate, and low and analyzed with alloHCT outcomes. Haplo donors were younger than MRD donors (median: 35 vs 51 years), whereas Haplo recipients were older than MRD recipients (median: 68 vs 54 years), were more likely to have a Karnofsky Performance Score ≤ 70 (76% vs 57%), 3+ comorbidities (54% vs 47%), and were in complete remission prior to alloHCT (58% vs 42%). In MRD alloHCT, a lower ratio of CD4+ to CD8+ effector memory cells in the donor was associated with lower 4-yr overall survival (OS; 25% vs 61%; P = .009), lower 4-yr progression free survival (PFS; 25% vs 58%; P = .014) and higher incidence of 1-yr transplant-related mortality (TRM; 39% vs 7%; P = .009) in recipients. A higher ratio of CD8+ effector memory to total NK cells measured in MRD recipients was associated with a higher incidence of grade II-IV aGvHD (63% vs 37%; P = .004) but was not statistically significant for III-IV aGvHD (23% vs 12%). In Haplo alloHCT, a lower ratio of total T-regulatory to CD4+ central memory cells in the donor was associated with lower 4-yr PFS (22% vs 60%; P = .0091). A higher ratio of CD4+ effector memory to CD8+ effector memory cells measured in Haplo recipients pre-alloHCT was associated with lower 4-yr OS (25% vs 88%; P = .0039). In both MRD and Haplo recipients, a higher ratio of CD4+ naïve to CD4+ central memory cells was associated with a higher incidence of grade II-IV aGvHD (64% vs 38%; P = .04). Evaluation of pre-alloHCT immune signatures of the donor and recipient may influence clinically meaningful patient outcomes in both MRD and Haplo transplants.

Immune reconstitution, vaccine responses, and rituximab use after ex-vivo CD34-selected myeloablative allogenic hematopoietic cell transplantation.

Myeloablative T cell depleted (CD34-selected) hematopoietic cell transplantation (HCT) is associated with less acute and chronic graft versus host disease (GVHD). We aimed to examine vaccine responses in relation to immune reconstitution and post HCT rituximab administration in this population. This single center retrospective study included 251 patients with hematological malignancies who received a first CD34-selected HCT between 2012 and 2015. Of 251 patients, 190 were alive 1 year after HCT. Among the entire population, 77 (30.7%) patients were vaccinated. After vaccine administration, 35/44 (80%), 30/75 (40%), 27/36 (75%), 33/65 (51%), 34/51 (51%), 22/28 (79%) and 20/34 (59%) of evaluable patients had protective antibody titers for haemophilus influenzae type B (Hib), Pneumococcus, Tetanus, Diphtheria, Pertussis, hepatitis A (HAV), and hepatitis B (HBV) respectively. Responders to the pneumococcal vaccine had a higher CD45RA T cell count than non responders, with 12/18 patients (66.7%) vs 11/32 (34.4%) p = 0.04. For pneumococcal vaccine, there was also a trend to higher total lymphocyte B cell count in responders vs non responders p = 0.06. Rituximab post HCT was given to 59/251 (23.5%) patients. No difference was found in immune reconstitution patterns for rituximab use between vaccine responders and not. Recipients of CD34-selected HCT may respond to vaccination, and T and B cell subsets could be useful to predict vaccine response.

Treatment of Patients with Acute Myeloid Leukemia with the Targeted Alpha-Particle Nanogenerator Actinium-225-Lintuzumab.

PURPOSE: The anti-CD33 antibody lintuzumab has modest activity against acute myeloid leukemia (AML). To increase its potency, lintuzumab was conjugated to actinium-225 (225Ac), a radionuclide yielding 4 α-particles. This first-in-human, phase I trial was conducted to determine the safety, pharmacology, and biological activity of 225Ac-lintuzumab. PATIENTS AND METHODS: Eighteen patients (median age, 64 years; range, 45-80) with relapsed or refractory AML received a single infusion of 225Ac-lintuzumab at activities of 18.5 to 148 kBq/kg. RESULTS: The maximum tolerated dose was 111 kBq/kg. Dose-limiting toxicities included myelosuppression lasting > 35 days in one patient receiving 148 kBq/kg and death from sepsis in two patients treated with 111 and 148 kBq/kg. Myelosuppression was the most common toxicity. Significant extramedullary toxicities were limited to transient grade 3 liver function abnormalities. Pharmacokinetics were determined by gamma counting serial whole blood, plasma, and urine samples at energy windows for the 225Ac daughters, francium-221 and bismuth-213. Two-phase elimination kinetics were seen with mean plasma t1/2 - α and t1/2 - ß of 1.9 and 38 hours, respectively. Peripheral blood blasts were eliminated in 10 of 16 evaluable patients (63%) but only at doses of ≥ 37 kBq/kg. Bone marrow blasts were reduced in 10 of 15 evaluable patients (67%), including 3 patients with marrow blasts ≤ 5% and one patient with a morphologic leukemia-free state. CONCLUSIONS: Therapy for AML with the targeted α-particle generator 225Ac-lintuzumab was feasible with an acceptable safety profile. Elimination of circulating blasts or reductions in marrow blasts were observed across all dose levels.

Early intestinal microbial features are associated with CD4 T-cell recovery after allogeneic hematopoietic transplant.

Low intestinal microbial diversity is associated with poor outcomes after allogeneic hematopoietic cell transplantation (HCT). Using 16S rRNA sequencing of 2067 stool samples and flow cytometry data from 2370 peripheral blood samples drawn from 894 patients who underwent allogeneic HCT, we have linked features of the early post-HCT microbiome with subsequent immune cell recovery. We examined lymphocyte recovery and microbiota features in recipients of both unmodified and CD34-selected allografts. We observed that fecal microbial diversity was an independent predictor of CD4 T-cell count 3 months after HCT in recipients of a CD34-selected allograft, who are dependent on de novo lymphopoiesis for their immune recovery. In multivariate models using clinical factors and microbiota features, we consistently observed that increased fecal relative abundance of genus Staphylococcus during the early posttransplant period was associated with worse CD4 T-cell recovery. Our observations suggest that the intestinal bacteria, or the factors they produce, can affect early lymphopoiesis and the homeostasis of allograft-derived T cells after transplantation.

Prolonged SARS-CoV-2 Infection in Patients with Lymphoid Malignancies.

Coronavirus disease 2019 (COVID-19) infection results in both acute mortality and persistent and/or recurrent disease in patients with hematologic malignancies, but the drivers of persistent infection in this population are unknown. We found that B-cell lymphomas were at particularly high risk for persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity. Further analysis of these patients identified discrete risk factors for initial disease severity compared with disease chronicity. Active therapy and diminished T-cell counts were drivers of acute mortality in COVID-19-infected patients with lymphoma. Conversely, B cell-depleting therapy was the primary driver of rehospitalization for COVID-19. In patients with persistent SARS-CoV-2 positivity, we observed high levels of viral entropy consistent with intrahost viral evolution, particularly in patients with impaired CD8+ T-cell immunity. These results suggest that persistent COVID-19 infection is likely to remain a risk in patients with impaired adaptive immunity and that additional therapeutic strategies are needed to enable viral clearance in this high-risk population. SIGNIFICANCE: We describe the largest cohort of persistent symptomatic COVID-19 infection in patients with lymphoid malignancies and identify B-cell depletion as the key immunologic driver of persistent infection. Furthermore, we demonstrate ongoing intrahost viral evolution in patients with persistent COVID-19 infection, particularly in patients with impaired CD8+ T-cell immunity.This article is highlighted in the In This Issue feature, p. 1.

Universal Engraftment after Allogeneic Hematopoietic Cell Transplantation Using Cryopreserved CD34-Selected Grafts.

As a result of the COVID-19 pandemic, most centers performing allogeneic hematopoietic cell transplantation (allo-HCT) have switched to the use of cryopreserved grafts. Previous investigators have suggested that cryopreserved allografts may heighten risk of nonengraftment. To date, no study has investigated the effect of cryopreservation of CD34-selected hematopoietic progenitor cells (CD34+ HPCs) used as the sole graft source. In this study, we sought to evaluate outcomes after unrelated donor or matched sibling allo-HCT with cryopreserved CD34+ HPCs. This was a single-center analysis of adult patients with hematologic malignancies who underwent allo-HCT with cryopreserved CD34-selected allo-HCT grafts between January 2010 and June 2017. All patients received ablative conditioning and antirejection prophylaxis with rabbit antithymocyte globulin. G-CSF-mobilized leukapheresis products underwent CD34 selection using the CliniMACS Reagent System. Cells were then cryopreserved in DMSO (final concentration 7.5%) to -90 °C using a controlled-rate freezing system before being transferred to vapor-phase liquid nitrogen storage. In internal validation, this method has shown 92% mean CD34+ cell viability and 99.7% mean CD34+ cell recovery. Engraftment was defined as the first of 3 consecutive days of an absolute neutrophil count of ≥0.5. Platelet recovery was recorded as the first of 7 consecutive days with a platelet count ≥20 K/µL without transfusion. Kaplan-Meier methodology was used to estimate overall survival (OS) and relapse-free survival (RFS), and cumulative incidence functions were used to estimate rates of relapse, nonrelapse mortality (NRM), and acute graft-versus-host disease (GVHD). A total of 64 patients received a cryopreserved CD34-selected graft. The median CD34+ cell count before cryopreservation was 6.6 × 106/kg (range, 1.4 to 16.1 × 106/kg), and the median CD3+ cell count was 2.0 × 103/kg (range, 0 to 21.1 × 106/kg). All patients were engrafted, at a median of 11 days post-HCT (range, 8 to 14 days). One patient had poor graft function in the setting of cytomegalovirus viremia, necessitating a CD34-selected boost on day +57. The median time to platelet recovery was 16 days (range, 13 to 99 days). The estimated 2-year OS was 70% (95% confidence interval [CI], 58% to 83%) with cryopreserved grafts versus 62% (95% CI, 57% to 67%) with fresh grafts (hazard ratio [HR], 0.86; 95% CI, 0.54 to 1.35; P = .5). The estimated 2-year RFS in the 2 groups was 59% (95% CI, 48% to 74%) versus 56% (95% CI, 51% to 61%; HR, 1.01; 95% CI, 0.68 to 1.51; P > .9). The cumulative incidence of relapse at 2 years was 29% (95% CI, 17% to 41%) versus 23% (95% CI, 19% to 27%; P = .16), and the cumulative incidence of NRM at 2 years was 17% (95% CI, 9% to 28%) versus 23% (95% CI, 19% to 28%; P = .24). The cumulative incidence of grade II-IV acute GVHD by day +100 was 16% with cryopreserved grafts (95% CI, 8% to 26%) and 16% (95% CI, 13% to 20%; P = .97) with fresh grafts. Moderate to severe chronic GVHD by day +365 occurred in only 1 recipient of a cryopreserved graft (2%). Our data show that in patients with hematologic malignancies who received cryopreserved allogeneic CD34+ HPCs, engraftment, GVHD, and survival outcomes were consistent with those seen in recipients of fresh allogeneic CD34+ HPC grafts at our center. Our laboratory validation and clinical experience demonstrate the safety of our cryopreservation procedure for CD34-selected allografts.

Interventions and outcomes of adult patients with B-ALL progressing after CD19 chimeric antigen receptor T-cell therapy.

CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has become a breakthrough treatment of patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, despite the high initial response rate, the majority of adult patients with B-ALL progress after CD19 CAR T-cell therapy. Data on the natural history, management, and outcome of adult B-ALL progressing after CD19 CAR T cells have not been described in detail. Herein, we report comprehensive data of 38 adult patients with B-ALL who progressed after CD19 CAR T therapy at our institution. The median time to progression after CAR T-cell therapy was 5.5 months. Median survival after post-CAR T progression was 7.5 months. A high disease burden at the time of CAR T-cell infusion was significantly associated with risk of post-CAR T progression. Thirty patients (79%) received salvage treatment of post-CAR T disease progression, and 13 patients (43%) achieved complete remission (CR), but remission duration was short. Notably, 7 (58.3%) of 12 patients achieved CR after blinatumomab and/or inotuzumab administered following post-CAR T failure. Multivariate analysis revealed that a longer remission duration from CAR T cells was associated with superior survival after progression following CAR T-cell therapy. In summary, overall prognosis of adult B-ALL patients progressing after CD19 CAR T cells was poor, although a subset of patients achieved sustained remissions to salvage treatments, including blinatumomab, inotuzumab, and reinfusion of CAR T cells. Novel therapeutic strategies are needed to reduce risk of progression after CAR T-cell therapy and improve outcomes of these patients.

A simplified CD34+ based preharvest prediction tool for HPC(A) collection.

BACKGROUND: Hematopoietic stem cell transplantation is an important treatment that is dependent on the collection of sufficient CD34+ hematopoietic progenitor cells. The peripheral blood CD34 count (PB CD34+ counts) measured by flow cytometry can be used in predicting CD34+ stem cell yields hours before the completion of collection. Previously described formulas to predict the yield have used many different variables. As such, there is currently no consensus on an industry-standard algorithm or formula. STUDY DESIGN AND METHODS: Retrospective reviews of same-day PB CD34+ counts and the ensuing absolute CD34+ yields of mobilized donors (allogeneic and autologous) were used to develop and validate a formula using regression analysis to predict the CD34+ stem cell yield. A metric of prediction correlation, using root mean square error (RMSE), was used to assess the robustness of our prediction formula in addition to comparisons with two other published formulas, as well as subset analysis. RESULTS: A formula in the form of y = mxb with r = 0.95 and 95% confidence intervals was generated and validated. The ratio of actual to predicted yield demonstrated a high correlation coefficient (r = 0.96) with linear regression and overall RMSE of 228.4, which was lower than the two prior studies (calculated RMSE = 330.8 and 405.2). Subset analyses indicated male patients, lymphoma patients, and patients >60 years of age demonstrated lower RMSEs. CONCLUSION: We have demonstrated a simple yet robust formula that can be used prospectively to accurately predict the CD34+ stem cell yield in both autologous and allogeneic donors, which also accounts for recipient weight.

CD8 T cells compensate for impaired humoral immunity in COVID-19 patients with hematologic cancer.

Cancer patients have increased morbidity and mortality from Coronavirus Disease 2019 (COVID-19), but the underlying immune mechanisms are unknown. In a cohort of 100 cancer patients hospitalized for COVID-19 at the University of Pennsylvania Health System, we found that patients with hematologic cancers had a significantly higher mortality relative to patients with solid cancers after accounting for confounders including ECOG performance status and active cancer status. We performed flow cytometric and serologic analyses of 106 cancer patients and 113 non-cancer controls from two additional cohorts at Penn and Memorial Sloan Kettering Cancer Center. Patients with solid cancers exhibited an immune phenotype similar to non-cancer patients during acute COVID-19 whereas patients with hematologic cancers had significant impairment of B cells and SARS-CoV-2-specific antibody responses. High dimensional analysis of flow cytometric data revealed 5 distinct immune phenotypes. An immune phenotype characterized by CD8 T cell depletion was associated with a high viral load and the highest mortality of 71%, among all cancer patients. In contrast, despite impaired B cell responses, patients with hematologic cancers and preserved CD8 T cells had a lower viral load and mortality. These data highlight the importance of CD8 T cells in acute COVID-19, particularly in the setting of impaired humoral immunity. Further, depletion of B cells with anti-CD20 therapy resulted in almost complete abrogation of SARS-CoV-2-specific IgG and IgM antibodies, but was not associated with increased mortality compared to other hematologic cancers, when adequate CD8 T cells were present. Finally, higher CD8 T cell counts were associated with improved overall survival in patients with hematologic cancers. Thus, CD8 T cells likely compensate for deficient humoral immunity and influence clinical recovery of COVID-19. These observations have important implications for cancer and COVID-19-directed treatments, immunosuppressive therapies, and for understanding the role of B and T cells in acute COVID-19.

Pediatric-inspired chemotherapy incorporating pegaspargase is safe and results in high rates of minimal residual disease negativity in adults up to age 60 with Philadelphia chromosome-negative acute lymphoblastic leukemia.

Administration of pediatric-inspired chemotherapy to adults up to age 60 with acute lymphoblastic leukemia (ALL) is challenging in part due to toxicities of asparaginase as well as myelosuppression. We conducted a multicenter phase II clinical trial (NCT01920737) investigating a pediatric-inspired regimen, based on the augmented arm of the Children's Cancer Group 1882 protocol, incorporating 6 doses of pegaspargase 2000 IU/m2, rationally synchronized to avoid overlapping toxicity with other agents. We treated 39 adults ages 20-60 years (median, 38 years) with newly-diagnosed ALL (n=31) or lymphoblastic lymphoma (n=8). Grade 3-4 hyperbilirubinemia occurred frequently and at higher rates in patients 40-60 (n=18) vs 18-39 (n=21) years (44 vs 10%, p=0.025). However, 8/9 patients re-challenged with pegaspargase did not experience recurrent grade 3-4 hyperbilirubinemia. Grade 3-4 hypertriglyceridemia and hypofibrinogenemia were common (each 59%). Asparaginase activity at 7-days post-infusion reflected levels associated with adequate asparagine depletion, even among those with antibodies to pegaspargase. Complete response (CR)/CR with incomplete hematologic recovery was observed post-induction in 38/39 (97%) patients. Among patients with ALL, rates of MRD negativity by multiparameter flow cytometry were 33% and 83% following Induction Phase I and Phase II, respectively. Event-free and overall survival at 3 years (67.8 and 76.4%) compare favorably to outcomes observed in other series. These results demonstrate pegaspargase can be administered in the context of intensive multi-agent chemotherapy to adults age ≤60 with manageable toxicity. This regimen may serve as an effective backbone into which novel agents may be incorporated in future frontline studies.

Favorable outcomes of COVID-19 in recipients of hematopoietic cell transplantation.

BACKGROUNDUnderstanding outcomes and immunologic characteristics of cellular therapy recipients with SARS-CoV-2 is critical to performing these potentially life-saving therapies in the COVID-19 era. In this study of recipients of allogeneic (Allo) and autologous (Auto) hematopoietic cell transplant and CD19-directed chimeric antigen receptor T cell (CAR T) therapy at Memorial Sloan Kettering Cancer Center, we aimed to identify clinical variables associated with COVID-19 severity and assess lymphocyte populations.METHODSWe retrospectively investigated patients diagnosed between March 15, 2020, and May 7, 2020. In a subset of patients, lymphocyte immunophenotyping, quantitative real-time PCR from nasopharyngeal swabs, and SARS-CoV-2 antibody status were available.RESULTSWe identified 77 patients with SARS-CoV-2 who were recipients of cellular therapy (Allo, 35; Auto, 37; CAR T, 5; median time from cellular therapy, 782 days; IQR, 354-1611 days). Overall survival at 30 days was 78%. Clinical variables significantly associated with the composite endpoint of nonrebreather or higher oxygen requirement and death (n events = 25 of 77) included number of comorbidities (HR 5.41, P = 0.004), infiltrates (HR 3.08, P = 0.032), and neutropenia (HR 1.15, P = 0.04). Worsening graft-versus-host disease was not identified among Allo recipients. Immune profiling revealed reductions and rapid recovery in lymphocyte populations across lymphocyte subsets. Antibody responses were seen in a subset of patients.CONCLUSIONIn this series of Allo, Auto, and CAR T recipients, we report overall favorable clinical outcomes for patients with COVID-19 without active malignancy and provide preliminary insights into the lymphocyte populations that are key for the antiviral response and immune reconstitution.FUNDINGNIH grant P01 CA23766 and NIH/National Cancer Institute grant P30 CA008748.

Evaluation of peripheral blood mononuclear cell collection by leukapheresis.

BACKGROUND: Adoptive immunotherapy using engineered lymphocytes has shown promising results in treating cancers even in patients who have failed other treatments. As the first essential step, the number of peripheral mononuclear cell (MNC) collection procedures is rapidly increasing. In this retrospective study, we reviewed the collection results to determine factors that affect MNC collection. STUDY DESIGN AND METHODS: We reviewed 184 collections that were performed on 169 adult allogenic donors and patients with acute lymphoid leukemia, chronic lymphoid leukemia, lymphoma, multiple myeloma, or solid-organ tumors. All the leukapheresis procedures were performed after a complete cell count with differential was obtained. Total blood volume (TBV) was defined as processed blood volume divided by patient blood volume. RESULTS: There was a significant association between the precollection MNC count (pre-MNC) and the MNC yields normalized by TBV (r = 0.926; p < 0.001) and a regression formula was created to predict MNC yields. Multiple regression analyses showed that pre-MNC, TBV, and precollection hemoglobin were strongly associated with MNC yield (R 2 = 0.866; F (3180) = 388.472; p < 0.001), and pre-MNC had the greatest influence on MNC yield (ß = 0.960; p < 0.001) followed by TBV (ß = 0.302; p < 0.001), and Hgb (ß = 0.136; p < 0.001). CONCLUSION: Our results suggest that the optimal time for MNC collection can be determined based on pre-MNC and that processing volume should be determined based on collection goal and pre-MNC to optimize and personalize the harvesting procedure.

Long-Term Follow-up of CD19 CAR Therapy in Acute Lymphoblastic Leukemia.

BACKGROUND: CD19-specific chimeric antigen receptor (CAR) T cells induce high rates of initial response among patients with relapsed B-cell acute lymphoblastic leukemia (ALL) and long-term remissions in a subgroup of patients. METHODS: We conducted a phase 1 trial involving adults with relapsed B-cell ALL who received an infusion of autologous T cells expressing the 19-28z CAR at the Memorial Sloan Kettering Cancer Center (MSKCC). Safety and long-term outcomes were assessed, as were their associations with demographic, clinical, and disease characteristics. RESULTS: A total of 53 adults received 19-28z CAR T cells that were manufactured at MSKCC. After infusion, severe cytokine release syndrome occurred in 14 of 53 patients (26%; 95% confidence interval [CI], 15 to 40); 1 patient died. Complete remission was observed in 83% of the patients. At a median follow-up of 29 months (range, 1 to 65), the median event-free survival was 6.1 months (95% CI, 5.0 to 11.5), and the median overall survival was 12.9 months (95% CI, 8.7 to 23.4). Patients with a low disease burden (<5% bone marrow blasts) before treatment had markedly enhanced remission duration and survival, with a median event-free survival of 10.6 months (95% CI, 5.9 to not reached) and a median overall survival of 20.1 months (95% CI, 8.7 to not reached). Patients with a higher burden of disease (≥5% bone marrow blasts or extramedullary disease) had a greater incidence of the cytokine release syndrome and neurotoxic events and shorter long-term survival than did patients with a low disease burden. CONCLUSIONS: In the entire cohort, the median overall survival was 12.9 months. Among patients with a low disease burden, the median overall survival was 20.1 months and was accompanied by a markedly lower incidence of the cytokine release syndrome and neurotoxic events after 19-28z CAR T-cell infusion than was observed among patients with a higher disease burden. (Funded by the Commonwealth Foundation for Cancer Research and others; ClinicalTrials.gov number, NCT01044069 .).

Phase 2 trial of a multivalent WT1 peptide vaccine (galinpepimut-S) in acute myeloid leukemia.

A National Cancer Institute consensus study on prioritization of cancer antigens ranked the Wilms tumor 1 (WT1) protein as the top immunotherapy target in cancer. We previously reported a pilot study of a multivalent WT1 peptide vaccine (galinpepimut-S) in acute myeloid leukemia (AML) patients. We have now conducted a phase 2 study investigating this vaccine in adults with AML in first complete remission (CR1). Patients received 6 vaccinations administered over 10 weeks with the potential to receive 6 additional monthly doses if they remained in CR1. Immune responses (IRs) were evaluated after the 6th and 12th vaccinations by CD4+ T-cell proliferation, CD8+ T-cell interferon-γ secretion (enzyme-linked immunospot), or the CD8-relevant WT1 peptide major histocompatibility complex tetramer assay (HLA-A*02 patients only). Twenty-two patients (7 males; median age, 64 years) were treated. Fourteen patients (64%) completed ≥6 vaccinations, and 9 (41%) received all 12 vaccine doses. Fifteen patients (68%) relapsed, and 10 (46%) died. The vaccine was well tolerated, with the most common toxicities being grade 1/2 injection site reactions (46%), fatigue (32%), and skin induration (32%). Median disease-free survival from CR1 was 16.9 months, whereas the overall survival from diagnosis has not yet been reached but is estimated to be ≥67.6 months. Nine of 14 tested patients (64%) had an IR in ≥1 assay (CD4 or CD8). These results indicated that the WT1 vaccine was well tolerated, stimulated a specific IR, and was associated with survival in excess of 5 years in this cohort of patients. This trial was registered at www.clinicaltrials.gov as #NCT01266083.

Method comparison study of peripheral blood CD34+ count performed on an Abbott CELL-DYN Sapphire hematology analyzer versus flow cytometry reference procedure (modified ISHAGE).

INTRODUCTION: CD34+ cell enumeration is a critical parameter used to determine the timing of apheresis collections of hematopoietic progenitor cell products (HPC(A)). Automated hematology analyzers equipped with flow cytometry capabilities may be a solution to the problem of limited access to standard flow cytometry testing. METHODS: We compared CD34+ cell enumeration using a reference flow cytometry procedure employing modified International Society of Hematotherapy and Graft Engineering (ISHAGE) analysis with a hematology analyzer /flow cytometer hybrid (CELL DYN (CD)Sapphire) using a sequential gating analysis designed to emulate the ISHAGE gating strategy. RESULTS: CD34+ cell values obtained from the ISHAGE and CD Sapphire analysis were plotted and compared in a linear regression analysis which showed a high degree of correlation (R2=0.96). No statistically significant (p=0.53) differences in CD34+ cell enumeration values were observed between the flow cytometer and automated hematology analyzer using manual analysis schema. CONCLUSIONS: We have demonstrated that an automated hematology analyzer equipped with a flow module can provide CD34+ cell enumeration results in the peripheral blood for clinical decision algorithms without the need for a dedicated flow cytometry laboratory.

Single-Tube 10-Fluorochrome Analysis for Efficient Flow Cytometric Evaluation of Minimal Residual Disease in Plasma Cell Myeloma.

OBJECTIVES: Widespread adoption of recent recommendations for minimal residual disease (MRD) detection in myeloma has partly been impeded by a paucity of studies detailing multiparameter flow cytometry (MPF) assay validation. In response, we have validated a novel and efficient single-tube 10-color assay for MRD detection that incorporates the recently recommended plasma cell markers. METHODS: Aspirate samples from 53 patients with plasma cell disorder were analyzed using a novel single-tube 10-color method. The limit of detection, precision of measurement, and linearity of measurement of our new assay were determined using serial dilution experiments. The stability of the new antibody cocktail and the viability/specificity of stained samples were evaluated using serial time course measurements. RESULTS: There was a high degree of quantitative agreement between our new 10-color method and an established eight-color method. Four positive samples detected by the 10-color assay were below or at the limit of detection of the eight-color assay, confirming its high sensitivity. In two cases, subsequent revision of the International Myeloma Working Group Uniform Response Criteria was necessary. CONCLUSION: Adoption of our validated 10-color assay would enable clinical laboratories to satisfy current MRD recommendations without significantly increasing the demands on current workflow practices.

Comparison of manual hematocrit determinations versus automated methods for hematopoietic progenitor cell apheresis products.

BACKGROUND: Allogeneic hematopoietic stem cell donor selection is based primarily on human leukocyte antigen degree of match and it often occurs without regard to the red blood cell (RBC) compatibility between donor and recipient. When major ABO-mismatched grafts are infused, it is imperative that an accurate determination of the incompatible RBC content is made to ensure that the product is safe for infusion. RBC content determination requires the hematocrit (Hct) parameter which can be obtained via manual (directly measured) or automated (calculated) methods. STUDY DESIGN AND METHODS: Ninety-seven apheresis hematopoietic progenitor grafts were assessed for Hct by manual testing and by four commercially available automated hematology analyzer instruments. A clinical model was developed to assess the frequency of unnecessary RBC reductions or alteration in standard infusion practice. RESULTS: Significant (p < 0.001) differences were observed where the manual Hct value was markedly lower than automated Hct values. At stringent incompatible RBC threshold of 10 mL, the number of preventable RBC reduction procedures ranged from 18% to 69%. CONCLUSION: Accurate determination of RBC content of hematopoietic progenitor grafts is essential for patient safety. Despite the rapidity and convenience offered by automated Hct methods, they significantly overestimate the incompatible RBC content of grafts, which may trigger unnecessary RBC reduction procedures or split infusions. In products where automated Hct methods indicate excessive amounts of incompatible RBCs are present, we advise the performance of confirmatory testing with a manual Hct method to ensure that the automated Hct value is not a false positive.

Evaluation of new automated hematopoietic progenitor cell analysis in the clinical management of peripheral blood stem cell collections.

BACKGROUND: Successful peripheral blood stem cell transplantation (PBSCT) depends on the collection and infusion of adequate numbers of peripheral blood progenitor cells (PBPCs). Several predictors of PBPC yield are used currently, including white blood cell (WBC) count and CD34 analysis. This study evaluated the utility of the new automated hematopoietic progenitor cell count available on Sysmex XN hematology analyzers (XN-HPCs) in PBSCT. STUDY DESIGN AND METHODS: The performance characteristics of XN-HPC, CD34+, and WBC analysis were compared using 107 matched peripheral blood and apheresis samples. RESULTS: Good correlation was observed between XN-HPC and CD34+ cell counts in peripheral blood (r = 0.88; slope, 0.81) and apheresis collections (r = 0.91; slope, 0.89). Moreover, peripheral blood XN-HPC and CD34 analysis showed comparable ability to predict successful PBPC harvests (≥2 × 10(6) CD34+ cells/kg). At a cutoff of 20 × 10(6) progenitor cells/L, peripheral blood XN- HPC and CD34 analysis both showed negative predictive values (NPVs) of 100% and positive predictive values (PPVs) of 55.4 and 63%, respectively. Using an optimized cutoff of 38 × 10(6) progenitor cells/L, derived from receiver operating characteristic analysis, the PPV for XN-HPC and CD34 analysis increased to 71.4 and 78.9%, respectively, with relatively unchanged NPVs (XN-HPC 97.7%, CD34+ 98.0%). In contrast, the correlation between peripheral blood WBC and CD34 analysis was poor (r = 0.48; slope, 669.85), and the peripheral blood WBC count (cutoff, 10 × 10(9) /L) was a poor predictor of PBPC harvest (NPV 60%, PPV 43.1%). CONCLUSION: XN-HPC compares favorably with CD34 analysis and may be a surrogate for CD34 analysis to predict optimal timing of PBPC collections.

Using the hemoglobin content of reticulocytes (RET-He) to evaluate anemia in patients with cancer.

OBJECTIVES: Evaluation of anemia, particularly iron deficiency, in patients with cancer is difficult. This study examined using the hemoglobin content of reticulocytes (RET-He) to rule out iron deficiency, as defined by serum iron studies (transferrin saturation <20%, serum iron <40 µg/dL, and ferritin <100 ng/mL), in an unselected cancer patient population. METHODS: Patients were entered into the study based on the existence of concurrent laboratory test requests for CBC and serum iron studies. RESULTS: Using a threshold of 32 pg/cell, RET-He ruled out iron deficiency with a negative predictive value (NPV) of 98.5% and 100%, respectively, in the study population (n = 209) and in a subpopulation of patients with low reticulocyte counts (n = 19). In comparison, the NPV of traditional CBC parameters (hemoglobin, <11 g/dL; mean corpuscular volume, <80 fL) was only 88.5%. CONCLUSIONS: These results support the use of RET-He in the evaluation of iron deficiency in a cancer care setting.

Efficacy and toxicity management of 19-28z CAR T cell therapy in B cell acute lymphoblastic leukemia.

We report on 16 patients with relapsed or refractory B cell acute lymphoblastic leukemia (B-ALL) that we treated with autologous T cells expressing the 19-28z chimeric antigen receptor (CAR) specific to the CD19 antigen. The overall complete response rate was 88%, which allowed us to transition most of these patients to a standard-of-care allogeneic hematopoietic stem cell transplant (allo-SCT). This therapy was as effective in high-risk patients with Philadelphia chromosome-positive (Ph(+)) disease as in those with relapsed disease after previous allo-SCT. Through systematic analysis of clinical data and serum cytokine levels over the first 21 days after T cell infusion, we have defined diagnostic criteria for a severe cytokine release syndrome (sCRS), with the goal of better identifying the subset of patients who will likely require therapeutic intervention with corticosteroids or interleukin-6 receptor blockade to curb the sCRS. Additionally, we found that serum C-reactive protein, a readily available laboratory study, can serve as a reliable indicator for the severity of the CRS. Together, our data provide strong support for conducting a multicenter phase 2 study to further evaluate 19-28z CAR T cells in B-ALL and a road map for patient management at centers now contemplating the use of CAR T cell therapy.