Evaluation of the CCL17/CCL22-CCR4 axis in pediatrics with B-cell acute lymphoblastic leukemia before and after a chemotherapy course.

AIMS: Acute lymphoblastic leukemia (ALL) is the most common type of pediatrics cancer. Chemokines exert different roles in leukemia process through leukocyte recruitment and regulation of disease severity. Due to the prominent roles of chemokine/receptor axes, this study aimed to measure the blood expression levels of CCR4 and their ligands in pediatrics with B-cell ALL (B-ALL). We also evaluated the impact of cytotoxic chemotherapy on this axis. MATERIAL AND METHOD: Thirty children suffering from B-ALL were included in the study and followed up for 30 days after completion of a chemotherapy course. The blood sampling was performed before and after chemotherapy. 30 healthy donors have also entered the study as control subjects. The mRNA expression of CCL17, CCL22 and CCR4 genes was determined by quantitative real-time PCR. The frequency of the peripheral blood mononuclear cells expressing CCR4 (CCR4 + PBMCs) was also evaluated by the flow cytometry method. Moreover, we evaluated the association of the CCL17/CCL22-CCR4 axis with some diagnostic, prognostic and predictive biomarkers in ALL patients. RESULTS: There was overexpression of the CCL17/CCL22-CCR4 axis along with lactate dehydrogenase (LDH) in pediatrics with B-ALL compared to healthy controls. After induction of chemotherapy, the blood expression levels of the CCL17/CCL22-CCR4 axis have reached the levels of healthy controls. The findings for the blood expression levels of CCR4 were also confirmed using flow cytometry. CONCLUSION: The CCL17/CCL22-CCR4 axis can be used as a novel predictive and prognostic biomarker in B-ALL.

Plasma microbial cell-free DNA following chimeric antigen receptor T cell therapy in pediatric patients with relapsed/refractory leukemia.

Chimeric antigen receptor (CAR) T cell therapy is a promising treatment for pediatric patients with relapsed or refractory B cell acute lymphoblastic leukemia (R/R B ALL). Cytokine release syndrome (CRS) is a common toxicity after CAR T cell therapy and fever is often the first symptom. Differentiating CRS from infection after CAR T cell therapy can be challenging. Plasma microbial cell free DNA (mcfDNA) is a novel diagnostic tool which allows for qualitative and quantitative assessment of over 1000 organisms. This pilot study sought to characterize mcfDNA results in pediatric patients with R/R B ALL in the first 2 months after CAR T cell therapy.

Dysregulated arginine metabolism in precursor B-cell acute lymphoblastic leukemia in children: a metabolomic study.

BACKGROUND: Precursor B-cell acute lymphoblastic leukemia (B-ALL) is the most common cancers in children. Failure of induction chemotherapy is a major factor leading to relapse and death in children with B-ALL. Given the importance of altered metabolites in the carcinogenesis of pediatric B-ALL, studying the metabolic profile of children with B-ALL during induction chemotherapy and in different minimal residual disease (MRD) status may contribute to the management of pediatric B-ALL. METHODS: We collected paired peripheral blood plasma samples from children with B-ALL at pre- and post-induction chemotherapy and analyzed the metabolomic profiling of these samples by ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS). Healthy children were included as controls. We selected metabolites that were depleted in pediatric B-ALL and analyzed the concentrations in pediatric B-ALL samples. In vitro, we study the effects of the selected metabolites on the viability of ALL cell lines and the sensitivity to conventional chemotherapeutic agents in ALL cell lines. RESULTS: Forty-four metabolites were identified with different levels between groups. KEGG pathway enrichment analyses revealed that dysregulated linoleic acid (LA) metabolism and arginine (Arg) biosynthesis were closely associated with pediatric B-ALL. We confirmed that LA and Arg were decreased in pediatric B-ALL samples. The treatment of LA and Arg inhibited the viability of NALM-6 and RS4;11 cells in a dose-dependent manner, respectively. Moreover, Arg increased the sensitivity of B-ALL cells to L-asparaginase and daunorubicin. CONCLUSION: Arginine increases the sensitivity of B-ALL cells to the conventional chemotherapeutic drugs L-asparaginase and daunorubicin. This may represent a promising therapeutic approach.

Relative expansion of CD19-negative very-early normal B-cell precursors in children with acute lymphoblastic leukaemia after CD19 targeting by blinatumomab and CAR-T cell therapy: implications for flow cytometric detection of minimal residual disease.

CD19-directed treatment in B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) frequently leads to the downmodulation of targeted antigens. As multicolour flow cytometry (MFC) application for minimal/measurable residual disease (MRD) assessment in BCP-ALL is based on B-cell compartment study, CD19 loss could hamper MFC-MRD monitoring after blinatumomab or chimeric antigen receptor T-cell (CAR-T) therapy. The use of other antigens (CD22, CD10, CD79a, etc.) as B-lineage gating markers allows the identification of CD19-negative leukaemia, but it could also lead to misidentification of normal very-early CD19-negative BCPs as tumour blasts. In the current study, we summarized the results of the investigation of CD19-negative normal BCPs in 106 children with BCP-ALL who underwent CD19 targeting (blinatumomab, n = 64; CAR-T, n = 25; or both, n = 17). It was found that normal CD19-negative BCPs could be found in bone marrow after CD19-directed treatment more frequently than in healthy donors and children with BCP-ALL during chemotherapy or after stem cell transplantation. Analysis of the antigen expression profile revealed that normal CD19-negative BCPs could be mixed up with residual leukaemic blasts, even in bioinformatic analyses of MFC data. The results of our study should help to investigate MFC-MRD more accurately in patients who have undergone CD19-targeted therapy, even in cases with normal CD19-negative BCP expansion.

Loss of CD22 expression and expansion of a CD22dim subpopulation in adults with relapsed/refractory B-lymphoblastic leukaemia after treatment with Inotuzumab-Ozogamicin.

Treatment options for relapsed or refractory B-lymphoblastic leukaemia (r/r B-ALL) are limited and the prognosis of these patients remains dismal, but novel immunotherapeutic options such as the anti-CD22 antibody-drug-conjugate Inotuzumab-Ozogamicin (InO) have improved outcomes in these patients. Flow cytometry is essential to assess antigen-expression prior to treatment initiation of antigen-directed immunotherapies. Here, we present flow cytometric and clinical data of three adult patients with r/r B-ALL who failed treatment with InO associated with reduced or lost antigen-expression. In addition, we present comparative data on two different diagnostic CD22-specific antibody clones that exhibit significant differences in staining intensities.

Cytokine gene polymorphisms are associated with response to blinatumomab in B-cell acute lymphoblastic leukemia.

Blinatumomab is a bispecific T cell-engaging antibody approved for treatment of relapsed/refractory (r/r) ALL, with 40%-50% complete response (CR)/CR with incomplete count recovery (CRi). Cytokine release syndrome (CRS) as a major adverse effect after blinatumomab therapy. Here, we evaluated the possible association between single-nucleotide polymorphisms (SNPs) in cytokine genes, disease response, and CRS in r/r ALL patients who received blinatumomab between 2012 and 2017 at our center (n = 66), using patients' archived DNA samples. With a median duration of 9.5 months (range: 1-37), 37 patients (56.1%) achieved CR/CRi, 54 (81.8%) experienced CRS (G1: n = 35, G2: n = 14, G3: n = 5), and 9 (13.6%) developed neurotoxicity. By multivariable analysis, after adjusting for high disease burden, one SNP on IL2 (rs2069762), odds ratio (OR) = 0.074 (95% CI: NE-0.43, P = .01) and one SNP on IL17A (rs4711998), OR = 0.28 (95% CI: 0.078-0.92, P = .034) were independently associated with CR/CRi. None of the analyzed SNPs were associated with CRS. To our knowledge, this is the first study demonstrating a possible association between treatment response to blinatumomab and SNPs. Our hypothesis-generated data suggest a potential role for IL-17 and IL-2 in blinatumomab response and justify a larger confirmatory study, which may lead to personalized blinatumomab immunotherapy for B-ALL.

Hypercalcemia and Disseminated Osteolytic Lesions With Normal Blood Counts and Absence of Circulating Blasts: A Rare Presentation of Childhood B-Lymphoblastic Leukemia.

Hypercalcemia and disseminated osteolytic bone lesions are a rare presentation of pediatric acute lymphoblastic leukemia (ALL). The authors report a 3-year-old boy who presented with hypercalcemia and diffuse osteolytic lesions involving axial and appendicular bones. He had normal complete blood count and the absence of blasts in peripheral smear; however, bone marrow aspirate and trephine were consistent with B-cell ALL. A review of the literature highlights the variable clinical outcome of this rare presentation depending on the presence of hypercalcemia and osteolytic lesions with or without chromosomal translocation t(17;19) and coagulation abnormalities. The patient had no coagulopathy and normal karyotype, and showed excellent response to initial treatment in terms of complete remission and negative minimal residual disease after standard-risk induction chemotherapy. Hypercalcemia with diffuse osteolytic lesions warrants bone marrow examination to rule out leukemia even in the absence of any abnormality in complete blood count. The case was reported for awareness of this rare presentation of ALL so that delays can be avoided for this potentially curable but life-threatening disease.

A Preliminary Study of FTIR Spectroscopy as a Potential Non-Invasive Screening Tool for Pediatric Precursor B Lymphoblastic Leukemia.

Early detection of the most common pediatric neoplasm, B-cell precursor lymphoblastic leukemia (BCP-ALL), is challenging and requires invasive bone marrow biopsies. The purpose of this study was to establish new biomarkers for early screening to detect pediatric leukemia. In this small cohort study, Fourier transform infrared (FTIR) spectra were obtained from blood sera of 10 patients with BCP-ALL and were compared with the control samples from 10 children with some conditions other than neoplasm. Using various analytical approaches, including a new physical model, some significant differences were observable. The most important include: the different peak area ratio 2965/1645 cm-1 (p = 0.002); the lower average percentage of both ß-sheet and ß-turn protein structures in the sera of BCP-ALL patients (p = 0.03); an AdaBoost-based predictive model for classifying healthy vs. BCP-ALL patients with 85% accuracy; and the phase shift of the first derivative in the spectral range 1050-1042 cm-1 correlating with white blood cell (WBC) and blast cell count in BCP-ALL patients contrary to the samples obtained from healthy controls. Although verification in larger groups of patients will be necessary, these promising results suggest that FTIR spectroscopy may have future potential for the early screening of BCP-ALL.

Blinatumomab for minimal residual disease in adults with B-cell precursor acute lymphoblastic leukemia.

Approximately 30% to 50% of adults with acute lymphoblastic leukemia (ALL) in hematologic complete remission after multiagent therapy exhibit minimal residual disease (MRD) by reverse transcriptase-polymerase chain reaction or flow cytometry. MRD is the strongest predictor of relapse in ALL. In this open-label, single-arm study, adults with B-cell precursor ALL in hematologic complete remission with MRD (≥10-3) received blinatumomab 15 µg/m2 per day by continuous IV infusion for up to 4 cycles. Patients could undergo allogeneic hematopoietic stem-cell transplantation any time after cycle 1. The primary end point was complete MRD response status after 1 cycle of blinatumomab. One hundred sixteen patients received blinatumomab. Eighty-eight (78%) of 113 evaluable patients achieved a complete MRD response. In the subgroup of 110 patients with Ph-negative ALL in hematologic remission, the Kaplan-Meier estimate of relapse-free survival (RFS) at 18 months was 54%. Median overall survival (OS) was 36.5 months. In landmark analyses, complete MRD responders had longer RFS (23.6 vs 5.7 months; P = .002) and OS (38.9 vs 12.5 months; P = .002) compared with MRD nonresponders. Adverse events were consistent with previous studies of blinatumomab. Twelve (10%) and 3 patients (3%) had grade 3 or 4 neurologic events, respectively. Four patients (3%) had cytokine release syndrome grade 1, n = 2; grade 3, n = 2), all during cycle 1. After treatment with blinatumomab in a population of patients with MRD-positive B-cell precursor ALL, a majority achieved a complete MRD response, which was associated with significantly longer RFS and OS compared with MRD nonresponders. This study is registered at www.clinicaltrials.gov as #NCT01207388.

Measurable residual disease detection by high-throughput sequencing improves risk stratification for pediatric B-ALL.

Early response to induction chemotherapy is an important prognostic factor in B-lymphoblastic leukemia (B-ALL). Here, we compare high-throughput sequencing (HTS) of IGH and TRG genes vs flow cytometry (FC) for measurable residual disease (MRD) detection at the end of induction chemotherapy in pediatric patients with newly diagnosed B-ALL. Six hundred nineteen paired pretreatment and end-of-induction bone marrow samples from Children's Oncology Group studies AALL0331 (clinicaltrials.gov #NCT00103285) (standard risk [SR]; with MRD by FC at any level) and AALL0232 (clinicaltrials.gov #NCT00075725) (high risk; with day 29 MRD <0.1% by FC) were evaluated by HTS and FC for event-free (EFS) and overall survival (OS). HTS and FC showed similar 5-year EFS and OS for MRD-positive and -negative patients using an MRD threshold of 0.01%. However, there was a high discordant rate with HTS identifying 55 (38.7%) more patients MRD positive at this threshold. These discrepant patients have worse outcomes than FC MRD-negative patients. In addition, the increased analytic sensitivity of HTS permitted identification of 19.9% of SR patients without MRD at any detectable level who had excellent 5-year EFS (98.1%) and OS (100%). The higher analytic sensitivity and lower false-negative rate of HTS improves upon FC for MRD detection in pediatric B-ALL by identifying a novel subset of patients at end of induction who are essentially cured using current chemotherapy and identifying MRD at 0.01% in up to one-third of patients who are missed at the same threshold by FC.

The early achievement of measurable residual disease negativity in the treatment of adults with Philadelphia-negative B-cell acute lymphoblastic leukemia is a strong predictor for survival.

The minimal or measurable residual disease (MRD) status following induction/consolidation chemotherapy is an important prognostic endpoint in adult patients with newly diagnosed acute lymphoblastic leukemia (ALL). However, the optimal time-point (TP) of MRD assessment and its impact on outcome remains unclear. We analyzed 215 patients with newly diagnosed Philadelphia negative B-cell ALL who received intensive chemotherapy, and had available MRD assessment by multicolor flow cytometry at two separate TPs. The median time to first TP (1TP) and second TP (2TP) were 24 and 110 days, respectively. At 1TP, 148 patients (68%) were MRD negative and 67 (32%) were positive. Of the 148 patients with negative MRD at 1TP, 147 (99%) maintained it through 2TP. Patients who were MRD negative at both TPs, early MRD responders, had the 3-year event-free survival (EFS), and overall survival (OS) rates of 65% and 76%, respectively. Patients with improved MRD status from positive to negative, late MRD responders, had lower 3-year EFS and OS rates, 42% and 58%, respectively (P = .001). Multivariate analysis showed that KMT2A (MLL) rearrangement and MRD positivity at 1TP were the only factors correlated with worse OS. In conclusion, the earlier achievement of MRD negative remission is a stronger prognostic factor for survival.

Results from an international phase 2 study of the anti-CD22 immunotoxin moxetumomab pasudotox in relapsed or refractory childhood B-lineage acute lymphoblastic leukemia.

BACKGROUND: In a multicenter phase 1 study of children with relapsed/refractory acute lymphoblastic leukemia (ALL), moxetumomab pasudotox, an anti-CD22 immunotoxin, demonstrated a manageable safety profile and preliminary evidence of clinical activity. A phase 2 study further evaluated efficacy. PROCEDURE: This international, multicenter, phase 2 study enrolled children with relapsed/refractory B-cell precursor ALL who received moxetumomab pasudotox 40 µg/kg intravenously every other day, for six doses per 21-day cycle. The primary objective was to evaluate the complete response (CR) rate. Secondary objectives included safety, pharmacokinetics, and immunogenicity evaluations. RESULTS: Thirty-two patients (median age, 10 years) were enrolled at 16 sites; 30 received study drug and were evaluable for safety; 28 were evaluable for response. The objective response rate was 28.6%, with three patients (10.7%) achieving morphologic CR, and five patients (17.9%) achieving partial response. Disease progression occurred in 11 patients (39.3%). Ten patients (33.3%) experienced at least one treatment-related serious adverse event, including capillary leak syndrome (CLS; n = 6), hemolytic uremic syndrome (HUS; n = 4), and treatment-related death (n = 1) from pulmonary edema. No differences were observed in inflammatory markers in patients who did or did not develop CLS or HUS. CONCLUSIONS: Despite a signal for clinical activity, this phase 2 study was terminated at interim analysis for a CR rate that did not reach the stage 1 target. Preclinical data suggest enhanced efficacy of moxetumomab pasudotox via continuous infusion or in combination regimens; thus, further studies designed to optimize the efficacy and safety of moxetumomab pasudotox in pediatric ALL may be warranted.

Blinatumomab for Acute Lymphoblastic Leukemia Relapse after Allogeneic Hematopoietic Stem Cell Transplantation.

Patients with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL) following allogeneic hematopoietic stem cell transplantation (alloHSCT) have a poor prognosis, and alternative therapies are needed for this patient population. Blinatumomab, a bispecific T cell engager immunotherapy, was evaluated in an open-label, single-arm, phase II study of adults with R/R Philadelphia chromosome-negative B cell precursor ALL and resulted in a rate of complete remission (CR) or CR with partial hematologic recovery of peripheral blood counts (CRh) of 43% within 2 treatment cycles. We conducted an exploratory analysis to determine the efficacy and safety of blinatumomab in 64 patients who had relapsed following alloHSCT before enrollment in the phase II study. Forty-five percent of the patients (29 of 64) achieved a CR/CRh within the first 2 cycles of treatment, 22 of whom had a minimal residual disease (MRD) response (including 19 with a complete MRD response). After 1 year and 3 years of follow-up, the median relapse-free survival was 7.4 months for patients who achieved CR/CRh in the first 2 cycles, and the median overall survival was 8.5 months; overall survival rate (Kaplan-Meier estimate) was 36% at 1 year and 18% at 3 years. Grade 3 and 4 adverse events were reported in 20 patients (31%) and 28 patients (44%), respectively, with grade 3 and 4 neurologic events in 8 and 2 patients, respectively, and grade 3 cytokine release syndrome in 2 patients. Eight patients had fatal adverse events, including 5 due to infections. Seven patients had grade ≤ 3 graft-versus-host disease during the study, none of which resulted in the discontinuation of blinatumomab or hospitalization. Our data suggest that blinatumomab is an effective salvage therapy in this patient population.

The poor prognosis of low hypodiploidy in adults with B-cell precursor acute lymphoblastic leukaemia is restricted to older adults and elderly patients.

The prognostic significance of low-hypodiploidy has not been extensively evaluated in minimal residual disease (MRD)-oriented protocols for adult acute lymphoblastic leukaemia (ALL). We analysed the outcome of hypodiploid adult ALL patients treated within Programa Español de Tratamientos en Hematología (PETHEMA) protocols. The 5-year cumulative incidence of relapse (CIR) of low-hypodiploid B-cell precursor (BCP)-ALL was significantly higher than that of high-hypodiploids (52% vs. 12%, P = 0.013). Low-hypodiploid BCP-ALL patients aged ≤35 years showed superior survival (71% vs. 21%, P = 0.026) and lower 5-year CIR (17% vs. 66%, P = 0.090) than low-hypodiploids aged >35 years. Older adults and elderly low-hypodiploid BCP-ALL patients show dismal prognosis although achieving an end-induction good MRD response.

Isobaric Multiplex Labeling Reagents for Carbonyl-Containing Compound (SUGAR) Tags: A Probe for Quantitative Glycomic Analysis.

Glycans are highly complex entities with multiple building units and different degrees of branched polymerization. Intensive research efforts have been directed to mass spectrometry (MS)-based qualitative and quantitative glycomic analysis due to the important functions of glycans. Among various strategies, isobaric labeling has become popular because of its higher multiplexing capacity. Over the past few years, several isobaric chemical tags have been developed for quantitative glycomics. However, caveats also exist for these tags, such as relatively low reporter ion yield for aminoxyTMT-labeled complex glycans. To overcome the limitations of existing isobaric chemical tags, we designed a class of novel isobaric multiplex reagents for carbonyl-containing compound (SUGAR) tags that can be used to label glycans for quantitative glycomic analysis. The quantitative performance including labeling efficiency, quantification accuracy, and dynamic range of these SUGAR tags has been evaluated, showing promising results. Finally, the 4-plex SUGAR tags have been utilized to investigate N-glycan changes of B-cell acute lymphoblastic leukemia (ALL) pediatric patients before and after chemotherapy.

A systematic literature review and meta-analysis of minimal residual disease as a prognostic indicator in adult B-cell acute lymphoblastic leukemia.

Minimal (or 'measurable') residual disease in acute lymphoblastic leukemia appears to be a prognostic indicator, with potential value in informing individualized treatment decisions. Complete understanding of the strength of the association between minimal residual disease and long-term outcomes is, however, lacking. A systematic literature review and meta-analysis were performed to elucidate the clinical significance of minimal residual disease with respect to relapse-free survival and overall survival in precursor B-cell acute lymphoblastic leukemia. A total of 23 articles and abstracts, most published between 2012 and 2016, were identified for inclusion in the primary meta-analysis. Typically, patients were in their first complete remission at the time of minimal residual disease assessment; in two studies, all patients were in their second, or later, complete remission. The primary analysis revealed improved relapse-free survival across all studies for patients who achieved minimal residual disease negativity (random effects hazard ratio, 2.34; 95% confidence interval, 1.91-2.86). Improved overall survival for patients who achieved minimal residual disease negativity was also observed (hazard ratio, 2.19; 95% confidence interval, 1.63-2.94). There was no observed difference in the impact of minimal residual disease status in subgroups based on disease stage, minimal residual disease sensitivity threshold level, Philadelphia chromosome status, histological phenotype, risk group, minimal residual disease testing location, minimal residual disease timing after induction, or minimal residual disease detection method. Despite heterogeneity in study design and patient populations between the contributing studies, these data provide a compelling argument for minimal residual disease as a clinical tool for assessing prognosis and guiding treatment decisions in precursor B-cell acute lymphoblastic leukemia.

Teetering on a liver's edge: a case report highlighting clinical decision-making in thrombocytopenia.

BACKGROUND: This report illustrates the importance of a detailed history and physical exam and careful analysis of hematologic parameters when diagnosing ITP. This case demonstrates that even with subtle deviations from typical ITP findings one must promptly reevaluate the diagnosis. This case also highlights the importance of peripheral smear review by an expert in pediatric hematopathology. CASE PRESENTATION: A previously healthy 10 year-old Asian boy presented with 2 months of easy bruising. Review of systems was negative for any constitutional symptoms. On examination, he appeared well but had numerous large ecchymoses. He had no appreciable lymphadenopathy or splenomegaly. The liver was palpable 1.5 cm below the costal margin. A complete blood count (CBC) showed: platelets = 17 × 109/L, hemoglobin = 128 g/L, white blood cell count = 5.43 × 109/L, and neutrophils = 1.63 × 109/L. A blood smear was reported as normal. Urate was 370 umol/L and lactate dehydrogenase (LDH) was 803 U/L. The child was admitted with a presumptive diagnosis of immune thrombocytopenic purpura (ITP) and treated with intravenous immunoglobulin. The following day, the blood smear was reviewed by a hematopathologist who identified blasts. A bone marrow aspiration (BMA) confirmed the diagnosis of precursor B-cell acute lymphoblastic leukemia. CONCLUSION: In children presenting with suspected ITP, leukemia should always be considered. A BMA was historically performed on all patients with presumed ITP to rule out leukemia. In 2011, the American Society of Hematology (ASH) stopped recommending routine BMA in patients suspected of having ITP. ASH advises in cases with unusual findings on history, physical examination or CBC, it is reasonable to perform a BMA. Our patient had mild hepatomegaly, which may have qualified him for a BMA. He also had an elevated LDH and urate, which are not listed as criteria for BMA by ASH but were considered atypical for ITP by the clinical team. A literature search did not reveal any primary data assessing these markers. While corticosteroids are a first line treatment in ITP, they must be reserved for when clinicians are confident that the patient does not have leukemia. Steroid administration prior to diagnosing leukemia results in delayed diagnosis and may increase the risk of complications and decrease survival.

Improving the safety of CAR-T cell therapy by controlling CRS-related coagulopathy.

The CD19-targeted chimeric antigen receptor T cell (CAR-T) therapy has been widely proved effective on relapsed and refractory (r/r) B cell acute lymphoblastic leukemia (B-ALL). Meanwhile, CAR-T therapy-related toxicities, including cytokine release syndrome (CRS) and neurological toxicities, are drawing researchers' attention. In addition, our research team notices that coagulopathy and even disseminated intravascular coagulation (DIC) are common problems during CAR-T therapy. In our phase 1/2 clinical trial (NCT02965092), 53 r/r B-ALL patients underwent leukapheresis on day - 11 and received lymphodepleting chemotherapy on day - 7 to day - 5. Finally, they received split infusions of anti-CD19 CAR-T cells on day 0 to day 2. Plasma concentrations of tissue factor (TF) and platelet endothelial cell adhesion molecular-1 (PECAM-1) were also measured to identify the mechanism of coagulation disorders. The overall 1-month remission rate of the 53 patients was 88.7%. During the treatment course, 19 patients experienced grade 3-4 CRS, 8 patients developed grade 2-3 neurological toxicities. Beyond that, 30 patients (30/53, 56.6%) suffered from coagulation disorders, and half of them should be diagnosed as DIC. Benefiting from replacement and anticoagulant therapy, 14 patients successfully got out of the conditions of DIC. Remarkably, the severity of coagulopathy was positively correlated with CRS grade. What is more, plasma TF and PECAM-1 levels indicated that vascular endothelial factors played key roles in the process of CRS-related coagulopathy. To conclude, coagulation disorders frequently happen during CAR-T therapy. TF and PECAM-1 are of great importance in the etiology and pathogenesis of coagulation problems. Early and proper interventions targeted at CRS-related coagulopathy contribute a lot to the control of side effects in CAR-T therapy.

Flow-cytometric minimal residual disease monitoring in blood predicts relapse risk in pediatric B-cell precursor acute lymphoblastic leukemia in trial AIEOP-BFM-ALL 2000.

BACKGROUND: Flow-cytometric monitoring of minimal residual disease (MRD) in bone marrow (BM) during induction of pediatric patients with acute lymphoblastic leukemia (ALL) is widely used for outcome prognostication and treatment stratification. Utilizing peripheral blood (PB) instead of BM might be favorable, but data on its usefulness are scarce. PROCEDURE: We investigated 1303 PB samples (days 0, 8, 15, 33, and 52) and 285 BMs (day 15) from 288 pediatric ALL patients treated in trial AIEOP-BFM ALL 2000. MRD was assessed by four-color flow cytometry and evaluated as relative, absolute, and kinetic result. RESULTS: In B-ALL only, PB measures from early time points correlated with relapse incidence (CIR). Best separation occurred at threshold <1 blast/µL at day 8 (5-year CIR 0.02 ± 0.02 vs 0.12 ± 0.03; P = 0.044). Patients with highest relapse risk were not distinguishable, but PB-MRD at days 33 and 52 correlated with prednisone response and postinduction BM-MRD by PCR (P < 0.001). Kinetic assessment did not convey any advantage. In multivariate analysis including day 15 BM-MRD, PB-MRD measures lost statistical power. CONCLUSIONS: In summary, PB-MRD in pediatric B-ALL correlates with outcome and risk parameters, but its prognostic significance is not strong enough to substitute for BM assessment in AIEOP-BFM trials. It might, however, be valuable in treatment environments not using multifaceted risk stratification with other MRD measures.

Peripheral blood flow cytometry for the diagnosis of pediatric acute leukemia: Highly reliable with rare exceptions.

BACKGROUND: Recent data have demonstrated the high sensitivity and specificity of peripheral blood flow cytometry (PBFC) for the diagnosis of pediatric leukemia; however, diagnostically significant immunophenotypic discrepancies between PBFC and bone marrow (BM) evaluation, which result in different lineage assignment and treatment protocols, can rarely occur. Here, we sought to further characterize the performance of PBFC for pediatric leukemia and highlight the exceptions when PBFC can result in misdiagnosis. METHODS: An institutional database was searched between 2012 and 2016 for cases of acute leukemia with concurrent PBFC and BM evaluation. Immunophenotyping results from the peripheral blood and BM using four or eight color flow cytometry, as well as BM cytochemical staining and immunohistochemistry, were compared. RESULTS: Two hundred ninety PBFC samples with concurrent BM evaluation were identified. Based on the final immunophenotypic classification, the cases were distributed as follows: 108 B-lymphoblastic leukemia (B-ALL), 57 T-lymphoblastic leukemia (T-ALL), 116 acute myeloid leukemia (AML), and 9 mixed-phenotype acute leukemia (MPAL). Among all cases, five had a diagnostically significant discrepancy between PBFC and BM evaluation. In three cases, the immunophenotype by PBFC was consistent with early T-cell precursor ALL (ETP-ALL), whereas BM evaluation demonstrated MPAL. Two cases were suspicious for acute megakaryoblastic leukemia (AMKL) and MPAL, T/myeloid by PBFC but were diagnosed as B-ALL and T-ALL in the BM. CONCLUSION: Immunophenotypic classification by PBFC is accurate (>98%) in almost all cases of pediatric leukemia with the rare exceptions of suspected ETP-ALL, MPAL, and AMKL. These PBFC diagnoses should be confirmed with BM immunophenotyping.