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Recipients of allogeneic hematopoietic stem cell transplantation (allo‐HSCT) are an immunocompromised group who are likely to develop severe complications and mortality because of coronavirus disease 2019 (COVID‐19). We report here a 61‐year‐old male patient of primary myelofibrosis who underwent an allo‐HSCT 6 years earlier, had chronic graft‐versus‐host disease (cGVHD) involving the liver, lung, eyes, and skin, (with recurrent episodes of pulmonary infections) who developed severe COVID‐19. The patient was treated with tocilizumab, and a combination of lopinavir/ritonavir, ribavirin, interferon‐β1b. He was discharged after 31 days with full recovery. Tocilizumab, a humanized monoclonal antibody against IL6, has been shown to benefit respiratory manifestations in severe COVID19. However, this is first report, to our knowledge, of its use and benefit in a post HSCT recipient.

AML is a highly heterogeneous disease with t(8;21)(q22;q22) as a frequently occurring aberration. While most studies show these patients to demonstrate a good response to standard chemotherapy, a lot of Indian and Western studies suggest otherwise. Trisomy 4 is a rare but a specific chromosomal abnormality in certain subtypes of AML. Although the significance of t(8;21) with trisomy 4 in AML remains uncertain, patients with this abnormality are typically associated with poor prognosis. Similarly, KIT mutations are also common with t(8;21) AML suggesting poorer outcomes. We report a case of AML with duplicated derivative 21 due to t(8;21), trisomy 4 and KIT mutation at baseline and an additional t(2;12) and ASXL2 mutation at relapse.

Acute Myeloid Leukemia (AML) is a heterogeneous disease with respect to morphology, immunophenotype, chromosomal abnormalities and genetic lesions. While a majority of AML cases harbour recurrent chromosomal abnormalities, several rare, apparently unique or novel aberrations may be identified by conventional cytogenetics. In fact, with the prognostic relevance of chromosomal abnormalities, and with the advent of new-age, target-specific therapy, identifying such aberrations becomes vital. In this study, we present a case of pediatric AML with ins(19;X)(q13.1;p11.2q28) and t(1;11)(q10;p10), both, novel, previously unreported chromosomal abnormalities in AML. Post induction, both these clonal cytogenetic abnormalities persisted. The documentation of this case will help determine the significance of these cytogenetic abnormalities. Also, this case exemplifies the importance of cytogenetics in the complete characterization and risk stratification of AML patients.

Accurate knowledge of expression patterns/levels of commonly used MRD markers in regenerative normal-B-cell-precursors (BCP) is highly desirable to distinguish leukemic-blasts from regenerative-BCP for multicolor flow cytometry (MFC)-based measurable residual disease (MRD) assessment in B-lymphoblastic leukemia (B-ALL). However, the data highlighting therapy-related immunophenotypic-shift in regenerative-BCPs is scarce and limited to small cohort. Herein, we report the in-depth evaluation of immunophenotypic shift in regenerative-BCPs from a large cohort of BALL-MRD samples. Ten-color MFC-MRD analysis was performed in pediatric-BALL at the end-of-induction (EOI), end-of-consolidation (EOC), and subsequent-follow-up (SFU) time-points. We studied normalized-mean fluorescent intensity (nMFI) and coefficient-of-variation of immunofluorescence (CVIF) of CD10, CD19, CD20, CD34, CD38, and CD45 expression in regenerative-BCP (early, BCP1 and late, BCP2) from 200 BALL-MRD samples, and compared them with BCP from 15 regenerating control (RC) TALL-MRD samples and 20 treatment-naive bone-marrow control (TNSC) samples. Regenerative-BCP1 showed downregulation in CD10 and CD34 expression with increased CVIF and reduced nMFI (p < 0.001), upregulation of CD20 with increased nMFI (p = 0.014) and heterogeneous CD45 expression with increased CVIF (p < 0.001). Immunophenotypic shift was less pronounced in the BCP2 compared to BCP1 compartment with increased CVIF in all but CD45 (p < 0.05) and reduced nMFI only in CD45 expression (p = 0.005). Downregulation of CD10/CD34 and upregulation of CD20 was higher at EOI than EOC and SFU time-points (p < 0.001). Regenerative-BCPs are characterized by the significant immunophenotypic shift in commonly used B-ALL-MRD markers, especially CD10 and CD34 expression, as compared to treatment-naive BCPs. Therefore, the templates/database for BMRD analysis must be developed using regenerative-BCP.

We accrued 201 patients of adult AML treated with conventional therapy, in morphological remission and evaluated MRD using sensitive error corrected next generation sequencing (NGS-MRD) and multiparameter flow cytometry (FCM-MRD) at the end of induction (PI) and consolidation (PC). Nearly 71% of patients harbored PI NGS-MRD and 40.9% harbored PC NGS-MRD (median VAF 0.76%). Patients harboring NGS-MRD had a significantly higher cumulative incidence of relapse (p=0.003), inferior overall survival (p=0.001) and relapse free survival (p

Measurable/minimal residual disease (MRD) status has been suggested as a powerful indicator of clinical-outcome in T-cell lymphoblastic leukemia/lymphoma (T-ALL). Multicolor flow cytometric (MFC)-based T-ALL MRD reports are limited and traditionally based on the utilization of markers-of-immaturity like TdT and CD99. Moreover, studies demonstrating the multicolor flow cytometric (MFC) approach for the assessment of T-ALL MRD are sparse. Herein, we describe an 11-marker, 10-color MFC-based T-ALL MRD method using an "approach of exclusion." Methods The study included 269 childhood T-ALL patients treated with a modified-MCP841 protocol. An 11-marker, 10-color MFC-based MRD was performed in bone marrow (BM) samples at the end-of-induction (EOI) and end-of-consolidation (EOC) time-points using Kaluza-version-1.3 software. Results We studied EOI-MRD in 269 and EOC-MRD in 105 childhood T-ALL patients. EOI-MRD was detectable in 125 (46.5%) samples (median, 0.3%; range, 0.0007-66.3%), and EOC-MRD was detectable in 34/105 (32.4%) samples (median, 0.055%; range, 0.0008-27.6%). Leukemia-associated immunophenotypes (LAIPs) found useful for MRD assessment were dual-negative CD4/CD8 (40.9%), dual-positive CD4/CD8 (23.3%) and only CD4 or CD8 expression (35.8%); dim/subset/dim-negative surface-CD3 (39%), dim/subset/dim-negative/negative CD5 (28.3%), dim/dim-negative/negative/heterogeneous CD45 (44.7%) and co-expression of CD5/CD56 (7.5%). EOI-MRD-positive status was found to be the most-relevant independent factor in the prediction of inferior relapse-free and overall survival. Conclusion We described an 11-marker 10-color MFC-based highly sensitive MRD assay in T-ALL using an approach of exclusion. The addition of CD4 and CD8 to the pan-T-cell markers in a 10-color assay is highly useful in T-ALL MRD assessment and extends its applicability to almost all T-ALL patients.

Panel based next generation sequencing was performed on a discovery cohort of AML with RUNX1-RUNX1T1. Supervised machine learning identified NRAS mutation and absence of mutations in ASXL2, RAD21, KIT and FLT3 genes as well as a low mutation to be associated with favorable outcome. Based on this data patients were classified into favorable and poor genetic risk classes. Patients classified as poor genetic risk had a significantly lower overall survival (OS) and relapse free survival (RFS). We could validate these findings independently on a validation cohort (n=61). Patients in the poor genetic risk group were more likely to harbor measurable residual disease. Poor genetic risk emerged as an independent risk factor predictive of inferior outcome. Using an unbiased computational approach based we provide evidence for gene panel-based testing in AML with RUNX1-RUNX1T1 and a framework for integration of genomic markers toward clinical decision making in this heterogeneous disease entity.

Background: Inconclusive knowledge persists regarding the course of chronic myeloid leukemia-chronic phase (CML-CP) patients with detectable abnormal blasts by flowcytometry at diagnosis. The 2016 WHO classification is not specific regarding subclassification of CML with

BackgroundRecently, anti-CD38 monoclonal antibody (Mab) therapy has become a focus of attention as an additional/alternative option for many hematological neoplasms including T-cell acute lymphoblastic leukemia (T-ALL). It has been shown that antitumor efficacy of anti-CD38-Mab depends on the level of CD38 expression on tumor cells. Reports on CD38 expression in T-ALL are scarce, and data on the effect of cytotoxic chemotherapy on CD38 expression are limited to very few samples. Moreover, it lacks entirely in refractory disease and in adult T-ALL. We report the flow cytometric evaluation of CD38 expression in T-ALL blasts at diagnosis and the effect of cytotoxic chemotherapy on its expression in measurable residual disease (MRD), refractory disease (MRD≥5%), and relapsed disease in a large cohort of T-ALL.MethodsThe study included 347 samples (188 diagnostic, 100 MRD, 24 refractory and 35 relapse samples) from 196 (children: 85; adolescents/adults: 111) patients with T-ALL. CD38-positive blasts percentages (CD38-PBPs) and expression-intensity (mean fluorescent intensity, CD38-MFI) were studied using multicolor flow cytometry (MFC). MFC-based MRD was performed at the end-of-induction (EOI-MRD, day 30–35) and end-of-consolidation (EOC-MRD, day 78–85) subsequent follow-up (SFU-MRD) points.ResultsPatients were classified into early thymic precursor subtype of T-ALL (ETPALL, 54/188, 28.7%), and non-ETPALL (134/188, 71.3%). Of 188, EOI-MRD assessment was available in 152, EOC-MRD was available in 96 and SFU-MRD was available in 14 patients. CD38 was found positive in 97.9% (184/188) of diagnostic, 88.7% (110/124) MRD (including 24-refractory) and 82.9% (29/35) relapsed samples. Median (95% CI) of CD38-PBPs/MFI in diagnostic, MRD, refractory, and relapsed T-ALL samples were, respectively, 85.9% (82.10%–89.91%)/4.2 (3.88–4.47), 74.0% (58.87%–83.88%)/4.6 (3.67–6.81), 79.6% (65.25%–96.11%)/4.6 (3.33–8.47) and 85.2% (74.48%–93.01%)/5.6 (4.14–8.99). No significant difference was noted in CD38 expression between pediatric versus adult and patients with ETPALL versus non-ETPALL. No change was observed in CD38-MFI between diagnostic versus MRD and diagnostic versus relapsed paired samples. However, we noticed a mild drop in the CD38-PBPs in MRD samples compared with the diagnostic samples (p=0.016).ConclusionWe report an in-depth analysis of CD38 expression in a large cohort of T-ALL at diagnosis, during chemotherapy, and at relapse. Our data demonstrated that CD38 is robustly expressed in T-ALL blasts with a little effect of cytotoxic chemotherapy making it a potentially effective target for antiCD38-Mab therapy.

Background: Measurable/minimal residual disease (MRD) status is suggested as a powerful indicator of clinical-outcome in T-cell lymphoblastic leukemia/lymphoma (T-ALL). Contrary to B-cell ALL, reports on T-ALL MRD are limited and mostly based on molecular methods, mainly from developed countries. Multicolor flow cytometry (MFC)-based T-ALL studies are very few. Clinically relevant cut-off levels and ideal time-point for MRD assessment are still inconclusive. In view of lack of T-ALL MRD data from the developing world, we evaluated the prognostic value of MFC-based post-induction (PI)-MRD assessment in T-ALL in the context of standard practice.Methods: We included 256 childhood-T-ALL patients (age < 15 years) treated with a modified-MCP841 protocol, which uses high-dose cytarabine during consolidation, as a part of standard hospital practice. MRD was studied using 10-color 11-antibody MFC with any level of detectable disease being considered positive. Post-induction (PI)-MRD was available in all patients, and post-consolidation (PC) MRD was available mostly in PI-MRD-positive patients (n = 88).Results: Three years cumulative-incidence-of-relapse (3years-CIR) in PI-MRD-positive patients was inferior to negative patients (46.3% vs. 18.4%). The median relapse-free-survival (RFS), event-free-survival (EFS) and overall-survival (OS) with hazard ratio (HR) of PI-MRD-positive patients were 21.4 months vs not reached (p < 0.0001, HR-4.7), 21.6 months vs. not-reached (p = 0.0003, HR-2.01) and 37.3 months vs. not reached (p = 0.026, HR-1.64) respectively. RFS, EFS and OS of patients with PI-MRD

The high expression of brain and acute leukemia, cytoplasmic (BAALC) and ETS-related gene (ERG) has been reported to influence the outcome in acute myeloid leukemia (AML), but due to limited prospective studies, their role as prognostic factors is unclear. At diagnosis, the prognostic value of BAALC and ERG expression with respect to other cytogenetic and molecular markers was analyzed in 149 AML patients. Patients were divided into quartiles which resulted in the formation of four groups (G1-G4) based on expression values of BAALC and ERG and clinical response defined across groups. Groups with similar survival probabilities were merged together and categorized subsequently as high versus low expressers. Patients with high BAALC and ERG expression had significantly lower overall survival (OS; BAALC: p = 0.001 at 5 years 29.4% vs. 69.8%; ERG: p < 0.0001 at 5 years 4% vs. 50.4%) and disease-free survival (BAALC: p = 0.001 at 5 years 19.5% vs. 69.8%; ERG: p < 0.0001 at 5 years 4.2% vs. 47%). Patients were further stratified combining BAALC and ERG expression in an integrative prognostic risk score (IPRS). After a median follow-up of 54 months (95% CI 45-63 months) among survivors, IPRS for high versus low expressers was a significant predictor for OS (BAALC + ERG: 4% vs. 71.6%, p < 0.0001) and DFS (BAALC + ERG: 4.5% vs. 74.1%, p < 0.0001). In a multivariate model, IPRS of BAALC + ERG expression retained prognostic significance for OS (hazard ratio [HR] 2.96, 95%CI 1.91-4.59, p < 0.001) and DFS (HR 3.61, 95%CI 2.26-5.76, p < 0.001).

// Nikhil Patkar 1, * , Rohan Kodgule 1, 5, * , Chinmayee Kakirde 1 , Goutham Raval 1 , Prasanna Bhanshe 1 , Swapnali Joshi 1 , Shruti Chaudhary 1 , Y. Badrinath 1 , Sitaram Ghoghale 1 , Shraddha Kadechkar 1 , Syed Hasan Khizer 2 , Sadhana Kannan 3 , Dhanalaxmi Shetty 4 , Anant Gokarn 2 , Sachin Punatkar 2 , Hasmukh Jain 2 , Bhausaheb Bagal 2 , Hari Menon 6 , Manju Sengar 2 , Navin Khattry 2 , Prashant Tembhare 1 , Papagudi Subramanian 1 and Sumeet Gujral 1 1 Haematopathology Laboratory, ACTREC, Tata Memorial Centre, Navi Mumbai, India 2 Adult Haematolymphoid Disease Management Group, Tata Memorial Centre, Mumbai, India 3 Biostatistics, ACTREC, Tata Memorial Centre, Navi Mumbai, India 4 Dept of Cytogenetics, ACTREC, Tata Memorial Centre, Navi Mumbai, India 5 Homi Bhabha National Institute, Training School Complex, Mumbai, India 6 Haemato-Oncology, CyteCare Cancer Hospital, Bangalore, India * These authors contributed equally to this work Correspondence to: Nikhil Patkar, email: nvpatkar@gmail.com Keywords: acute myeloid leukemia; NPM1; measurable residual disease; next-generation sequencing; multiparameter flow cytometry Received: April 16, 2018 Accepted: November 16, 2018 Published: November 27, 2018 ABSTRACT Detection of measurable residual disease (MRD) by mutation specific techniques has prognostic relevance in NPM1 mutated AML ( NPM1 mut AML). However, the clinical utility of next generation sequencing (NGS) to detect MRD in AML remains unproven. We analysed the clinical significance of monitoring MRD using ultradeep NGS (NGS-MRD) and flow cytometry (FCM-MRD) in 137 samples obtained from 83 patients of NPM1 mut AML at the end of induction (PI) and consolidation (PC). We could monitor 12 different types of NPM1 mutations at a sensitivity of 0.001% using NGS-MRD. We demonstrated a significant correlation between NGS-MRD and real time quantitative PCR (RQ-PCR). Based upon a one log reduction between PI and PC time points we could classify patients as NGS-MRD positive ( 1log reduction). NGS-MRD, FCM-MRD as well as DNMT3A mutations were predictive of inferior overall survival (OS) and relapse free survival (RFS). On a multivariate analysis NGS-MRD emerged as an independent, most important prognostic factor predictive of inferior OS (hazard ratio, 3.64; 95% confidence interval [CI] 1.58 to 8.37) and RFS (hazard ratio, 4.8; 95% CI:2.24 to 10.28). We establish that DNA based NPM1 NGS MRD is a highly useful test for prediction of relapse and survival in NPM1 mut AML.

Background: 2008 World Health Organization (WHO) classification of hematolymphoid neoplasms (HLN) has classified them based on morphology, results of various ancillary techniques, and clinical features.[1] There are no studies looking at the applicability of WHO classification. Aims: The aim of the study was to calculate proportions of all HLN subtypes seen during 1-year period based on 2008 WHO classification of HLN and study applicability and also shortcomings of practices in a tertiary care center in India. Materials and Methods: This was a 1-year retrospective study (January 1st, to December 31st, 2010) where cases were identified using hospital/laboratory electronic records. Old follow-up and referral cases were excluded from the study. Only newly diagnosed cases classified into categories laid down by 2008 WHO classification of HLN included. Results: Out of 2118 newly diagnosed classifiable cases, 1602 (75.6%) cases were of lymphoid neoplasms, 489 (23.1%) cases of myeloid neoplasms, 16 (0.8%) cases of histiocytic and dendritic cell neoplasms, and 11 (0.5%) cases of acute leukemias of ambiguous lineage. Overall, most common HLN subtype was diffuse large B-cell lymphoma (n = 361, 17.0%). Precursor B-lymphoblastic leukaemia/lymphoma (n = 177, 48.2%) was the most common subtype within pediatric age group. Conclusions: All major subtypes of HLN were seen at our center and showed trends almost similar to those seen in other Indian studies. Molecular/cytogenetic studies could not be performed on a significant number of cases owing to logistic reasons (unavailability of complete panels and also cost-related issues) and such cases could not be classified as per the WHO classification system.

Introduction: Copy number alterations (CNA) have been described in childhood precursor B-lineage acute lymphoblastic leukemia (B-ALL) which in conjunction with chromosomal abnormalities drive leukemogenesis. There is no consensus on the clinical incorporation of CNA in B-ALL. An integrated genomic classification (IGC) has been proposed which includes CNA and cytogenetics. Methods: We correlated this IGC with immunophenotypic minimal residual disease (MRD) as well as other standard criteria for 245 patients of B-ALL such as National Cancer Institute (NCI) risk, D+8 prednisolone response, cytogenetics, and ploidy status. Results: MRD was detectable in 81 patients (33.1%). The most common abnormalities were seen in CDKN2A/B (25.7%) followed by PAX5(20%), ETV6(16.7%), IKZF1(15.5%), Rb1(5.3%), BTG (3.3%), EBF1(2.0%), and PAR1(0.8%). On integrating CNA into the IGC, 170 patients (69.4%) were classified into good genomic risk (GEN-GR) whereas 75 (30.6%) belonged to the poor genomic risk (GEN-PR) category. The IGC showed a significant correlation with MRD and NCI risk. The presence of CNA predicted MRD clearance in intermediate cytogenetics group. Conclusion: These data seem to indicate that in addition to cytogenetics, CNA should be incorporated into routine clinical testing and risk algorithms for B-ALL. The IGC is of prognostic relevance and offers an additional avenue for prognostication and risk-adapted therapy.

Introduction The monitoring of a patient's response to chemotherapy, called, measurable residual disease (MRD) is one of the most important predictors of outcome in Acute Myeloid Leukemia (AML). Although universally applicable, FCM-MRD for AML suffers from low sensitivity as compared to precursor B lineage acute lymphoblastic leukemia. Here, we evaluated the clinical utility of error corrected next generation sequencing (NGS) to detect MRD (NGS-MRD) in AML using single molecule molecular inversion probes (smMIPS). We compare NGS-MRD and FCM-MRD and determine their impact on patient outcome. We demonstrate that error corrected NGS-MRD at early timepoints in therapy is an independent and significant predictor of outcome in patients of AML treated with conventional therapies. Methods We created a 35 gene "hotspot" panel comprising of a pool of 302 smMIPS. In brief, this panel covers regions of 35 commonly mutated genes in AML.FLT3-ITD were detected using a novel one-step PCR based NGS assay. Post mapping, singleton reads (originating from one UMI) were discarded and consensus family based variant calling was performed. We then created a site and mutation specific error model to ascertain the relevance of an observed variant at each site. A limit of detection (LOD) experiment demonstrated a lower detection limit of 0.05%. For FLT3-ITD the LOD was 0.002%. A total of 393 adult patients of AMLwere accrued over a period of six years.Patients were treated with standard 3+7 induction followed by 3 doses of HiDAC. Allogeneic bone marrow transplantation was offered where feasible. Somatic mutations at diagnosis were evaluated using a smMIPS based 50 gene myeloid panel which was applicable to 327 patients [83.2% of AMLs, median 2 mutations per case (range 1 - 6 trackable mutations)].MRD assessment could be performed in 201 adult patients of AML in morphological remission (not performed in the rest because of suboptimal quality DNA at MRD time points or missing sample).Samples were sequenced on multiple S4 flow cells of a NovaSeq 6000 using 150PE chemistry.FCM-MRD was obtained from the bone marrow at end of induction (PI, n=200) and end of first consolidation cycle (PC, n=98). NGS-MRD sample also obtained at the same time points (PI, n=196& PC, n=127) from the bone marrow (n=266) or peripheral blood (n=45). Results The interaction of mutations that were trackable at diagnosis can be seen in Figure 1A. A total of 345 mutations could be detected in 196 patients (Figure 1B) with a median VAF of 1.01% [0.82% after exclusion of mutations in DNMT3A, TET2, ASXL1 (DTA) genes; (median of 2 mutations for PI and one for PC timepoint)]. The median consensus read coverage was 11,127 for the smMIPS assay, whereas for the FLT3-ITD assay it was 13,96,366.The median follow-up of the cohort was 42.3 months. The presence of NGS-MRD (70.9%) was associated with inferior overall survival (OS; p=0.001) [hazard ratio(HR)- 2.24; 95% confidence interval (CI)- 1.47 to 3.43] and relapse free survival (RFS; p=0.0002) [HR- 2.28; 95% CI- 1.58 to 3.31] at PI time point as well as PC time points [40.94% positive; OS (p=0.008)(HR- 1.92; 95% CI- 1.14 to 3.22) and RFS (p=0.004)(HR- 1.90; 95% CI- 1.18 to 3.05)].Similarly, FCM-MRD (44%) was predictive of inferior OS (p=0.0002)(HR- 2.08; 95% CI- 1.38 to 3.13)and RFS (p=0.0008)(HR- 1.81; 95% CI- 1.26 to 2.60) at PI as well as PC time points [21.4% positive, OS (p=0.04)(HR- 1.87; 95% CI- 0.89 to 3.91) and RFS (p=0.001)(HR- 2.38; 95% CI- 1.17 to 4.81)]. On multivariate analysis post induction NGS MRD emerged as the most important independent prognostic factor predictive of inferior outcome for OS [HR- 1.94; 95% CI-1.15 to 3.27; (p Conclusion In conclusion, we demonstrate that error corrected panel-based sequencing is feasible for MRD monitoring in AML and may offer an advantage over existing techniques. Maximum clinical utility may be leveraged by combining FCM and NGS modalities. Figure Disclosures No relevant conflicts of interest to declare.

BACKGROUND Measurable residual disease (MRD) assessment using multicolor flow cytometry (MFC) has become the center point of pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL) risk stratification and therapeutic management. The addition of new markers can improve the accuracy and applicability of MFC-based MRD assay further. Herein, we evaluated the utility of a new marker, CD304/neuropilin-1, in the assessment of MFC-based MRD. METHODS Expression patterns of CD304 were studied in leukemic blasts from BCP-ALL patients and in normal precursor B cells (NPBC) from uninvolved non-BCP-ALL bone marrow samples using 10-color MFC. MRD was monitored at end-of-induction (EOI; Days 35-40) and end-of-consolidation (Day 78-80) time points. RESULTS We studied CD304 expression in 300 pediatric BCP-ALL patients and found it positive in BCP-ALL blasts in 41.7% of diagnostic samples. It was significantly associated with ETV6-RUNX1 (p

Immune dysfunction is critical in pathogenesis of cutaneous T-cell lymphoma (CTCL). Few studies have reported abnormal cytokine profile and dysregulated T-cell functions during the onset and progression of certain types of lymphoma. However, the presence of IL9-producing Th9 cells and their role in tumor cell metabolism and survival remain unexplored. With this clinical study, we performed multidimensional blood endotyping of CTCL patients before and after standard photo/chemotherapy and revealed distinct immune hallmarks of the disease. Importantly, there was a higher frequency of “skin homing” Th9 cells in CTCL patients with early (T1 and T2) and advanced-stage disease (T3 and T4). However, advanced-stage CTCL patients had severely impaired frequency of skin-homing Th1 and Th17 cells, indicating attenuated immunity. Treatment of CTCL patients with standard photo/chemotherapy decreased the skin-homing Th9 cells and increased the Th1 and Th17 cells. Interestingly, T cells of CTCL patients express IL9 receptor (IL9R), and there was negligible IL9R expression on T cells of healthy donors. Mechanistically, IL9/IL9R interaction on CD3+ T cells of CTCL patients and Jurkat cells reduced oxidative stress, lactic acidosis, and apoptosis and ultimately increased their survival. In conclusion, coexpression of IL9 and IL9R on T cells in CTCL patients indicates the autocrine-positive feedback loop of Th9 axis in promoting the survival of malignant T cells by reducing the oxidative stress. Implications: The critical role of Th9 axis in CTCL pathogenesis indicates that strategies targeting Th9 cells might harbor significant potential in developing robust CTCL therapy.

Introduction: One of the mainstays of chemotherapy in acute myeloid leukemia (AML) is induction with a goal to achieve morphological complete remission (CR). However, not all patients by this remission criterion achieve long-term remission and a subset relapse. This relapse is explained by the presence of measurable residual disease (MRD). Methods: We accrued 451 consecutive patients of adult AML (from March 2012 to December 2017) after informed consent. All patients received standard chemotherapy. MRD testing was done at post-induction and, if feasible, post-consolidation using 8- and later 10-color FCM. Analysis of MRD was done using a combination of difference from normal and leukemia-associated immunophenotype approaches. Conventional karyotyping and FISH were done as per standard recommendations, and patients were classified into favorable, intermediate, and poor cytogenetic risk groups. The presence of FLT3-ITD, NPM1, and CEBPA mutations was detected by a fragment length analysis-based assay. Results: As compared to Western data, our cohort of patients was younger with a median age of 35 years. There were 62 induction deaths in this cohort (13.7%), and 77 patients (17.1%) were not in morphological remission. The median follow-up was 26.0 months. Poor-risk cytogenetics and the presence of FLT3-ITD were significantly associated with inferior outcome. The presence of post-induction MRD assessment was significantly associated with adverse outcome with respect to OS (p = 0.01) as well as RFS (p = 0.004). Among established genetic subgroups, detection of MRD in intermediate cytogenetic and NPM1 mutated groups was also highly predictive of inferior outcome. On multivariate analysis, immunophenotypic MRD at the end of induction and FLT3-ITD emerged as independent prognostic factors predictive for outcome. Conclusion: This is the first data from a resource-constrained real-world setting demonstrating the utility of AML MRD as well as long-term outcome of AML. Our data is in agreement with other studies that determination of MRD is extremely important in predicting outcome. AML MRD is a very useful guide for guiding post-remission strategies in AML and should be incorporated into routine treatment algorithms.

Background Multiparametric flow cytometry (MFC) is a popular technique for minimal residual disease (MRD) analysis. However, its applicability is still limited to 90% of B-cell precursor acute lymphoblastic leukemia (BCPALL) due to two major issues, i.e. a proportion of cases do not express adequate leukemia associated immunophenotype (LAIPs) with currently used markers and drug-induced antigen modulation. Hence, the incorporation of additional reliable markers is required for the further improvement of MFC-based MRD evaluation. We studied the utility of new markers in improvising MFC-based MRD detection in BCPALL. Methods Expression-patterns of six new markers, i.e. CD24, CD44, CD72, CD73, CD86, and CD200 were studied in leukemic-blasts from ninety childhood BCPALL patients and in hematogones from 20 uninvolved staging bone marrow (BM) and ten postinduction non-BCPALL BM samples using eight-color MFC. The utility of these new markers in the day 35 postinduction MRD evaluation was determined. Results Frequencies of LAIPs of CD73, CD86, CD72, CD44, CD200, and CD24 in diagnostic samples were 76.7, 56.7, 55.6, 50, 28.9, and 20%, respectively. Differential expression of all new markers was highly significant (P

Background CD19 is a B-cell specific marker, expressed on all stages of B-lymphocytes including plasma cells. It is widely used in the flow cytometric immunophenotyping (FCI) of B-cell and plasma cell malignancies. The analysis approach of FCI for the diagnosis and monitoring of B-cell acute lymphoblastic leukemia (B-ALL) is totally based on the CD19-based primary gating strategy and it would be challenging to study B-ALL without CD19 expression. Since CD19 negative B-ALL are extremely rare, we report three cases of B-ALL with negative expression of CD19 and discussed its implication in the diagnosis, residual disease monitoring and future targeted therapy. Methods Peripheral blood (PB) and bone marrow (BM) samples from three cases suspicious of acute leukemia were studied for morphology, cytochemistry, immunophenotyping and cytogenetics. FCI was performed using a comprehensive six to eight-color multiparametric assay. The cytogenetic studies for standard recurrent genetic translocations were performed by FISH & Karyotyping. Results The three cases studied were diagnosed as B-ALL based on the expression of CD10, CD20, CD22, CD34, and CD79a by leukemic blasts. CD19 was studied using two different clones (i.e. J3-119 & HIB-19) and found to be severely down regulated in all three cases. There were no significant differentiating features in morphology. Cytogenetic studies were negative for recurrent translocations. Conclusion We report three cases of extremely rare CD19 negative B-ALL. Lack of awareness of negative CD19 expression in B-ALL can leads to incorrect immunophenotypic diagnosis and monitoring of B-ALL, especially in laboratories using limited markers. © 2016 International Clinical Cytometry Society

We document the characteristics of BCR-ABL kinase domain mutations (KDM) in the largest study from India comprising of 385 patients and demonstrate that more than half (51.9%) of these patients have detectable abnormalities in the KD both in adult and in pediatric chronic myelogenous leukemia (CML). These comprise singly occurring missense mutations (25.5%), polyclonal/compound point mutations (4.9%), and insertions/deletions (29.6%). Missense mutations were most commonly seen in the imatinib-binding region followed by the P-loop. The commonest mutation in our dataset was T315I. Other common missense mutations were Y253H, M244V, and F317L. A high prevalence of BCR-ABL exon7 deletion (p.R362fs*) was also seen (25.5% of the entire cohort), whereas the 35bpintron-derived insertion/truncation mutation detected in 12 patients. In the pediatric age group, 58.8% of patients harbored missense mutations, polyclonal/compound mutations as well as insertions and deletions. We detected 11 novel mutations (seven missense mutations and four insertions/deletions).

Background: The expression of CD20 in precursor B-cell ALL has been associated with poor outcomes. The addition of rituximab with intensive chemotherapy in this subset of ALL has led to improvement in the event-free survival. Further increment in outcomes require novel approaches. Bortezomib is an active drug in relapsed ALL as well as has synergistic activity with rituximab in B-cell lymphomas; thus the addition of bortezomib to rituximab and chemotherapy may improve the outcomes in CD20-positive precursor B-cell ALL. Methods: We conducted a phase II study to test the activity of bortezomib and rituximab in combination with a paediatric inspired regimen during induction therapy in newly diagnosed adolescent and adults (>14 years of age) with CD20-positive, Philadelphia (Ph)-negative precursor B-ALL, with bone marrow measurable residual disease (MRD) negativity at the end of induction (EOI) as the primary endpoint. Results: From December 2017 through August 2019, a total of 35 patients were enrolled. A total of 70.99% patients achieved EOI MRD negative status. MRD negative rates improved to 88% post consolidation. There was no significant increase in toxicity with addition of bortezomib and rituximab to standard chemotherapy. The incidence of neuropathy was 26% ( Conclusion: The combination of bortezomib, rituximab and paediatric-inspired ALL regimen is active and well tolerated in in de-novo CD20 positive Ph-negative precursor B-ALL. Disclosures No relevant conflicts of interest to declare.

Ploidy, besides known translocations in lymphoblasts, is a strong predictor of prognosis in B- cell progenitor acute lymphoblastic leukemia (BCP-ALL). While hyperdiploidy with >50 chromosomes shows a favourable outcome, hypodiploidy with

Modern biology depends heavily on optics-based instruments to understand the underlying structural and functional details of cells and biomolecules. Flow cytometry is one such technique where the biomarkers identified by imaging techniques can be quantified with great speed. The capacity to resolve, quantify, and sort the distinct population of cells or organelles based on their expression of markers with rapid pace is characteristic of flow cytometry. Laser flow cytometry is commonly used in basic and clinical research as well as diagnostics and disease monitoring. Some of the key applications of flow cytometry are immunophenotyping of surface and intracellular markers, cell cycle analysis, genome estimation, ploidy analysis, chromosome analysis, calcium influx, pH, membrane potential, fluorescent reporter proteins, antigen quantitation, etc.

Introduction: There is paucity of data from India about the outcomes of patients with various hematological malignancies. Since its formation in 2009, the adult hematolymphoid disease management group of the Tata Memorial Centre is dedicated to the treatment of hematological malignancies alone. In this report, we present the outcomes of patients treated at our centre over a 5 year period for various haematological malignancies in both transplant and non-transplant setting. Methods: This is a retrospective analysis of all patients registered in adult hematolymphoid disease management group between 1st January 2010 to 31st December 2014. Patients not treated at our centre were excluded from survival analysis. The cut off date for survival analysis was 31st January 2016. Results: Overall, 1869, 3633 and 544 patients with acute leukemias, various lymphomas and myeloma respectively were registered at our centre from 1st January 2010 to 31st December 2014. Of these, 1178 (63%), 3091 (85%) and 454 (83%) respectively received treatment at our centre. The cumulative probability of 5 year overall survival for patients with acute leukemias, Hodgkin's lymphoma, non-Hodgkin lymphoma and myeloma treated at our centre is 40%, 85%, 78% and 40% respectively. Four hundred and fifteen stem cell transplants were done between 14th November 2007 to 31st December 2014 with 46% being allogeneic and 54% being autologous. The 5 year overall survival of patients with allogenic and autologous transplant was 52% and 63% respectively. Conclusions: This is the largest single centre data on outcomes of various haematological malignancies from India. This real world data identifies areas which need further attention to improve outcomes.

INTRODUCTION: The Pediatric Hematolymphoid Disease Management Group (PHL-DMG) at a tertiary cancer care hospital developed extensive patient support programs to improve retention and outcomes while focusing on protocols adapted to meet patient needs. An audit of measures and outcomes was done for a 7-year period from January 2010 to December 2016. MATERIALS AND METHODS: DMG protocols and patient support activities over the study period were documented and audited. Data was retrieved from internal databases and records. Measures taken and their impact were assessed by descriptive analytical tools. Survival outcomes were calculated using Kaplan–Meier method on SPSS v. 24™ software. RESULTS: Holistic patient support measures were undertaken through a charitable foundation entirely under pediatric oncology. Activities included infrastructure growth, socioeconomic support, provision of accommodation, nutrition, education, and multiple blood component donation drives. Patient registrations increased from 502 in 2009 to 874 in 2016, with the steepest rise in acute lymphoblastic leukemia (ALL) – 330 (2009) to 547 (2016). Treatment refusal and abandonment rates decreased from 32% to 3.4% over the same period, and male to female ratio decreased from 2.56 to 2.28:1. Early mortality in acute myeloid leukemia (AML) fell within 2 years from 26.7% in 2009 to 7%. Five-year overall survival (OS) was 69.5% for all patients registered in 2010, whereas disease-specific 5-year OS was ALL 67.1%, AML 49.3%, chronic myeloid leukemia 100%, Hodgkin lymphoma 90.4%, and non-Hodgkin lymphoma 74.2%. CONCLUSIONS: Holistic patient support-specific activities and adapted protocols made a measurable impact on patient outcomes. High survival outcomes of patients have been achieved despite relatively few receiving salvage therapies or stem cell transplant.

Background Minimal/measurable residual disease (MRD) testing by flow cytometry (FC) has been proposed as a potential surrogate clinical endpoint in plasma cell myeloma (PCM) clinical trials. As a result, effort has gone into standardizing this approach on PCM patients. Aims To assess inter-laboratory variation in FC MRD testing of PCM patients in an independent inter-laboratory study. Methods A dilution series of five stabilized bone marrow samples manufactured to contain 0%, 0.1%, 0.01%, 0.001%, and 0.0001% neoplastic plasma cells (PCs) were tested blind, using standardized FC PCM MRD assays by 10 international laboratories. Results Laboratories' assays broadly adhered to the consensus guidelines; however, some deviations were identified in panel design, fluorochrome conjugates, and lysis reagents. Despite this, all laboratories that returned results detected neoplastic PCs down to 0.001% of leucocytes. 6/8 laboratories detected neoplastic PCs at a level of 0.0001%. Quantitative data returned by laboratories showed good consensus and linearity with increasing variation at lower levels of MRD. However, examples of analytical and post analytical error were identified. Summary/conclusion Broadly standardized PCM MRD FC assays can attain the lower limit of detection (LOD) required by current and future clinical trials, an important consideration in establishing PCM MRD testing as a surrogate clinical marker in PCM clinical trials. Laboratories' assays showed good linearity, encouraging the prediction of survival based on log reduction in neoplastic PC populations in future clinical trials. However, the deviations from consensus guidelines identified in this study would suggest that if PCM MRD assays are further standardized interlaboratory variation could be reduced. © 2018 International Clinical Cytometry Society.

Introduction: Over the past decade, we have moved on from a predominantly morphological and clinical classification of myeloproliferative neoplasms (MPN) to a more evolved classification that accounts for the molecular heterogeneity that is unique to this subgroup of hematological malignancies. This usually incorporates mutations in Janus kinase 2 (JAK2), MPL, and calreticulin (CALR) genes. In this manuscript, we report the frequency of these mutations in a cohort of Indian patients at a tertiary cancer center. Materials and Methods: One hundred and thirty cases of MPN were included in this study. These cases were diagnosed and classified based on the World Health Organization 2008 criteria. JAK2 and MPL mutations were detected using high sensitivity allele-specific polymerase chain reaction using fluorescent labeled primers followed by capillary electrophoresis. A subset of JAK2 and CALR mutations were assessed using a fragment length assay. Results: Among the MPN, we had 20 cases of polycythemia vera (PV), 34 cases of essential thrombocythemia (ET), and 59 of myelofibrosis (MF). JAK2, MPL, and CALR mutations were mutually exclusive of each other. Seventeen cases were categorized as MPN unclassifiable (MPN-U). JAK2p.V617F and MPL mutations were present in 60% (78 of 130) and 5.3% (7 of 130) of all MPN. All the PV cases harbored the JAK2 p.V617F mutation. A total of 23.8% (31 of 130) of patients harbored CALR mutations. CALR exon 9 mutations were detected in 60.8% (14 of 23) and 50% (5 of 10) of JAK2 and MPL negative MF and ET cases, respectively. MPN-U cases included three JAK2 p.V617F positive, two MPL p.W515 L, and 12 CALR positive cases. Ten different types of CALR indels (8 deletions and 2 insertions) were detected of which Type I and Type II mutations were the most common, occurring at a frequency of 45.1% (14 of 31) and 22.5% (7 of 31), respectively. Discussion and Conclusion: We report frequencies of JAK2 p. V617F, MPL exon 10 and CALR mutations in 130 patients similar to those reported in western literature. These mutations carry not only diagnostic but also prognostic relevance.

Abnormal DNA ploidy is a valuable prognostic factor in many neoplasms, especially in hematological neoplasms like B-cell acute lymphoblastic leukemia (B-ALL) and multiple myeloma (MM). Current methods of flow-cytometric (FC) DNA-ploidy evaluation are either technically difficult or limited to three- to four-color immunophenotyping and hence, challenging to evaluate DNA-ploidy in minute tumor population with background rich of its normal counterpart cells and other hematopoietic cells. We standardized a novel sensitive and easy method of simultaneous evaluation of six- to seven-color immunophenotyping and DNA-ploidy using a dye-FxCycle Violet (FCV). Linearity, resolution, and coefficient of variation (CV) for FCV were studied using chicken erythrocyte nuclei. Ploidy results of FCV were compared with Propidium iodide (PI) in 20 samples and intra-assay variation for FCV was studied. Using this six-color immunophenotyping & FCV-protocol DNA-ploidy was determined in bone-marrow samples from 124 B-ALL & 50 MM patients. Dilution experiment was also conducted to determine the sensitivity in detection of aneuploidy in minute tumor population. FCV revealed high linearity and resolution in 450/50 channel. On comparison with PI, CV of Go/G1-peak with FCV (mean-CV 4.1%) was slightly higher than PI (mean-CV 2.9%) but had complete agreement in ploidy results. Dilution experiment showed that aneuploidy could be accurately detected up to the limit of 0.01% tumor cells. Intra-assay variation was very low with CV of 0.005%. In B-ALL, hypodiploidy was noted in 4%, hyperdiploidy in 24%, near-hyperdiploidy in 13% and remaining 59% were diploid. In MM, hypodiploidy was in 2%, hyperdiploidy in 58%, near-hyperdiploidy in 8% and remaining 30% were diploid. FCV-based DNA-ploidy method is a sensitive and easy method for simultaneous evaluation of six-color immunophenotyping and DNA analysis. It is useful in DNA-ploidy evaluation of minute tumor population in cases like minimal residual disease and MM precursor conditions.

Atypical breakpoints and variant APL cases involving alternative chromosomal aberrations are seen in a small subset of acute promyelocytic leukemia (APL) patients. Over 7 different partner genes for RARA have been described. Although rare, these variants prove to be a diagnostic challenge and require combination of advanced cytogenetic and molecular techniques for accurate characterization. Heterogeneity occurs not only at the molecular level but also at clinico-pathological level influencing treatment response and outcome. In this case series we describe the molecular heterogeneity of APL seen in a single tertiary referral centre with a focus on seven variant APL cases from a single tertiary cancer center in India over a period of two and a half years. We discuss five cases with PLZF-RARA fusion and two novel PML-RARA variants, including a Bcr3 variant involving fusion of PML exon4 and RARA exon3 with an additional 40 nucleotides originating from RARA intron2, another involving exon 6 of PML and exon 3 of RARA with addition of 126 nucleotides, which mapped to the central portion of RARA intron 2 To the best of our knowledge this is the first of kind case series from India

IL-6 activity in normal plasma cells (nPCs) and abnormal plasma cells (aPCs) is CD126 (subunit of IL-6 receptor) dependent. We quantified CD126 expression on nPCs and aPCs in monoclonal gammopathy of undetermined significance (MGUS), smoldering myeloma (SMM), and multiple myeloma (MM). CD126 was detected on all nPCs and aPCs indicating that CD126 does not have diagnostic utility. CD126 expression was higher in aPCs than in nPCs in 85% SMM but only 41% MGUS and there was evidence that CD126 was higher in aPCs than nPCs in the SMM (p = .048) but not MGUS (p = .96) patients. There is also a greater association between nPC and aPC CD126 expression in low risk MGUS than observed in high risk MGUS and SMM, suggesting normal regulation of CD126 decreases with disease progression. Future studies need to elucidate the role of bone marrow milieu versus escape from normal CD126 regulation in malignant transformation of clonal plasma cells.

The clinical use of flow cytometric DNA ploidy assay has been extended towards stratifying the risk of diseases, such as monoclonal gammopathies or B cell acute lymphoblastic leukemia, and to detect circulating tumor cells, both of which require detection of minute cell populations. This unit describes a protocol for determining DNA ploidy in fixed samples with simultaneous surface immunophenotyping. It is an easy method for simultaneous 6- to 8-color immunophenotyping and DNA content analysis using FxCycle Violet (FCV; DAPI) dye. This protocol is a one-step modification of routine multicolor immunophenotyping that includes surface staining followed by fixation and then DNA staining with FCV. It utilizes mature lymphocytes from the sample as an internal control for determination of DNA index. It is a sensitive method that allows DNA-ploidy determination and cell cycle analysis in a rare tumor population as low as 100 events, as well as DNA ploidy determination in various subsets of hematopoietic cells in the same sample based on their immunophenotype. © 2017 by John Wiley & Sons, Inc.

Introduction: Juvenile myelomonocytic leukaemia (JMML) is a clonal haematopoietic disorder occurring in pediatric age group usually characterized by uncontrolled granulocytic and monocytic lineage proliferation and a poor outcome. JMML is characterised by aberrant signal transduction of the RAS signalling pathways, usually manifesting in molecular alteration of one of the five cardinal genes: NF1, NRAS, KRAS, PTPN11 and CBL. Recent high-throughput studies have started to push the horizon of JMML associated mutations wider and have proposed molecular-based risk algorithms. We comprehensively evaluated the genomic profile of JMML that were referred to our hospital for diagnosis and treatment. Methods: We developed a 51 gene (103 kB) low-cost targeted sequencing myeloid panel based on single molecule molecular inversion probes. This focussed panel interrogated sets of genes implicated in pathogenesis of myeloid malignancies. A total of 50 children with clinical and pathological features of JMML were sequenced at high coverage using this assay on an Illumina MiSeq. Results:The median age of our cohort was 2 years, with a male preponderance. Among the 50 patients, 43 (86%) harboured mutations in one of the RAS/MAPK pathway genes. The most frequently mutated gene in our cohort was PTPN11 (14, 28%), and NRAS (14, 28%), followed by NF1 mutation in 22% (11) cases (Figure 1). Interestingly, 20% (10) of children had more than one mutation, with 5 cases harbouring two RAS pathway mutations. Of these 5 patients, one patient harboured two coexistent mutations in the NF1 gene, three patients had coexistent PTPN11 and NF1 mutations and one patient had a coexistent NF1 and NRAS mutations. Additionally, two patients also had an ASXL1 mutation, coexistent with NF1 and NRAS mutations respectively. Other non-RAS pathway mutations involved ABL1, ATRX, SETBP1, SH2B3 and ZRSR2 genes. The median variant allele frequency of RAS pathway mutations detected was 40.75%. Monosomy 7 was detected in 32% (16) patients, and five of these did not harbour any RAS pathway mutations. The follow up data revealed that 37 (74%) of these patients have succumbed to the disease. In our cohort, only five patients received an allogenic stem cell transplant, owing to economic constraints; two of these patients have succumbed to the disease. The median time period from diagnosis to death was 7.2 months in the cohort. On survival analysis, patients with PTPN11 mutations showed a trend to shorter overall survival, compared to their wildtype counterparts (p=0.7, median OS 10.6 months vs 38.1 months). Additionally, patients harbouring more than one mutation also showed a trend to shorter OS (p=0.64, median OS 10.3 months vs 38.1 months). Among the thirteen patients who are still on regular follow-up, two patients have relapsed with disease progression to acute myeloid leukemia and T/myeloid mixed phenotypic acute leukemia respectively. Conclusion: Our study represents the largest cohort of JMML from a single centre in the Indian subcontinent. This study depicted that almost 90% cases of JMML harbor at least one mutation with 86% harbouring at least one RAS pathway mutation. Presence of PTPN11 mutations and co-existence of more than one mutation may be the major determinants of outcome in JMML. Figure 1 Disclosures No relevant conflicts of interest to declare.

Background: Minimal Residual Disease (MRD) is a powerful predictor of event-free survival in acute lymphoblastic leukemia (ALL). However, as T-ALL is less common, MRD studies are limited, often with small cohorts, and even fewer have been done by flowcytometry-based MRD (FC-MRD). There have also been different time-points such as Post-Induction (PI-MRD), and late or Post-Consolidation (PC-MRD) that have shown significant correlation with overall, event, and relapse-free survival (OS, EFS & RFS). As the available literature is still not conclusive, we investigated the impact of FC-MRD on survival in childhood T-ALL at a large tertiary cancer care centre in India. Methods: Children less than 15-years age diagnosed with T-ALL from Jan-2014 to May 2018 were treated uniformly on a modified MCP-841 protocol that included a 4-drug induction (vincristine, prednisolone, l-asparaginase, daunomycin), and consolidation with high-dose cytarabine (24gm/m2 in 3 equal legs for children below 3-years, and 16gm/m2 in two equal legs, for 3 or more years age). Post-consolidation therapy followed the pattern of Interim Maintenance, two Delayed Intensification cycles, and 18 months of Maintenance. Central Nervous System (CNS)-directed therapy consisted of intrathecal methotrexate in all cycles, and those with CNS involvement received additional Cranial Radiation of 18Gy. In early-thymic-precursor (ETP-ALL) immunophenotype patients, dexamethasone replaced prednisolone in Induction. The protocol did not include High-Dose Methotrexate. FC-MRD was estimated by 10-color FC-MRD assay on Navios flow-cytometer (Beckman Coulter, Inc.) at Post-Induction(day-35), and Post-Consolidation(day-78) for those PI-MRD positive(+ve). FC-MRD was analyzed on Kaluza® software v-1.3. Any detectable value was taken as positive. Statistical analysis was performed using MedCalc Statistical Software®. Results: Of 368 eligible patients diagnosed at our centre in the study period, 81 did not undergo PI-MRD (14- Induction deaths, 13- treatment abandonment, 54- referral to other institute/ time-point missed/ did not consent/ other reasons). Another 18 abandoned treatment within 100 days of diagnosis and were also excluded. In the remaining 269, median age was 10-years (range:1-15), M:F-3.8:1. Median presenting WBC was 96.7 x 103/cmm (range:1.14-849), and thirteen patients had ETP. PI-MRD was positive in 125(46%) patients (median MRD -0.3%, range:0.0007-43.6%) of which 58(46.4%) developed medullary relapse, compared to 17 of 144(11.6%) for PI-MRD negative(-ve) patients, with Hazard Ratio (HR) for risk of medullary-relapse for PI-MRD+ve being 5.02(95% CI:3.16-7.96; p Conclusion: We conclude that 10-color FC-MRD done Post-Induction and Post-Consolidation detecting any residual disease reliably identifies those at highest risk of relapse and any other event. PI-MRD+ is an independent, and also the most important risk-factor for any event, and if PC-MRD is also positive, relapse occurs early. Figure 1 Disclosures No relevant conflicts of interest to declare.

Introduction: Core binding factor acute myeloid leukemia (CBF-AML) is one of the commonest subtypes of AML characterized presence of t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22). It is characterised by a high frequency of somatic mutations especially in RAS and tyrosine kinase signalling pathways. Here we investigated the feasibility of improving risk prediction of CBF-AML using machine learning algorithms. Methods: We developed a next generation sequencing panel that targeted 50 genes implicated in the pathogenesis of myeloid malignancies using single molecule molecular inversion probes. This panel was used to sequence 106 patients of CBF-AML accrued over a six year period (March 2012 - December 2018) treated with conventional "3 + 7" chemotherapy. Post data analysis, we devised a supervised machine learning (ML) approach for identification of mutations most likely to predict for favorable outcome in CBF-AML. We included somatic mutations in genes occurring in CBF-AML at a frequency of >5%. A total of 11 variables were included for feature selection to predict for favorable outcome (including mutations in ASXL2, CSF3R,FLT3, KIT, NF1, NRAS, RAD21, TET2 and WT1 genes as well as mutation burden). Approaches for supervised ML were naïve bayes, generalized linear model, logistic regression, deep learning and random forest methods. Based on the ML results top 6 selected variables were allotted an individual score. A final score for that case was devised as a sum total of the individual scores. These sum were used to generate a genetic risk for a patient. Overall survival (OS) was calculated from date of diagnosis to time of last follow up or death. Relapse free survival (RFS) was calculated from date of CR till time to relapse or death or last follow up if in CR. Results of the genetic risk were analyzed for their impact on OS and RFS using log rank test. Multivariate analysis was performed using cox proportional hazards regression model. Results: The median follow up of the cohort was 27.6 months. A total of 181 somatic mutations were identified in this subset of AML with 86.7% harbouring at least one somatic mutation (median = 2). Based on ML data, a genetic score was formulated that incorporated mutations in RAD21, FLT3, KIT D816, ASXL2, NRAS genes as well as high mutation burden (≥2) into two genetic risk classes (favorable risk and poor ML derived genetic genetic risk). Patients classified as poor genetic risk had a significantly lower OS [median OS: 34.8 months; 95% confidence interval (CI) (14.2-34.8); p=0.0086] and RFS [median RFS: 17.9 months; 95%CI (12.7-33.6); p=0.0043] as compared to patients with favorable genetic risk (median OS and RFS not reached). These results can be seen in Figure 1. On multivariate analysis poor genetic risk was the most important independent risk factor that predicted for inferior OS [hazard ratio(HR), 2.7; 95% CI 1.3 to 5.7] and RFS (HR, 2.6; 95% CI:1.3 to 5.1). Conclusions In a proof of concept, we describe a novel ML derived genomics scoring model that provides a mechanism to risk stratify CBF-AML, a seemingly homogeneous disease entity. This study, to the best of our knowledge represents a novel application of ML to CBF mutated AML. Our data indicates that this scoring system will be useful in identifying CBF mutated AML patients who are at higher risk of relapse and distinguishes them from patients who are truly good risk. Figure 1 Disclosures No relevant conflicts of interest to declare.

Detection of measurable residual disease (MRD) by mutation specific techniques has prognostic relevance in NPM1 mutated AML (NPM1mut AML). However, the clinical utility of next generation sequencing (NGS) to detect MRD in AML remains unproven. We analysed the clinical significance of monitoring MRD using ultradeep NGS (NGS-MRD) and flow cytometry (FCM-MRD) in 137 samples obtained from 83 patients of NPM1mut AML at the end of induction (PI) and consolidation (PC). We could monitor 12 different types of NPM1 mutations at a sensitivity of 0.001% using NGS-MRD. We demonstrated a significant correlation between NGS-MRD and real time quantitative PCR (RQ-PCR). Based upon a one log reduction between PI and PC time points we could classify patients as NGS-MRD positive (1log reduction). NGS-MRD, FCM-MRD as well as DNMT3A mutations were predictive of inferior overall survival (OS) and relapse free survival (RFS). On a multivariate analysis NGS-MRD emerged as an independent, most important prognostic factor predictive of inferior OS (hazard ratio, 3.64; 95% confidence interval [CI] 1.58 to 8.37) and RFS (hazard ratio, 4.8; 95% CI:2.24 to 10.28). We establish that DNA based NPM1 NGS MRD is a highly useful test for prediction of relapse and survival in NPM1mut AML.

Objectives: Anti-CD20 (rituximab), anti-CD52 (alemtuzumab), anti-CD22 (BL22, HA22), and anti-CD25 (Oncotac) are therapeutic options that are the mainstay or in preclinical development for the treatment of chronic lymphocytic leukemia (CLL). Studies suggest that levels of surface antigen expression may affect response to monoclonal antibody–based therapy. Methods: Using the flow cytometric Quantibrite method (BD Biosciences, San Jose, CA) to determine antibodies bound per cell, we quantified the levels of surface expression of CD20, CD22, CD25, and CD52 in CLL cells from 28 untreated patients. Results: The CLL cells in all cases expressed CD20, CD22, and CD52 but 4 (14%) cases were negative for CD25. Although the ranking of levels of expression from highest to lowest was CD52, CD20, CD22, and CD25, the level of antigen expression on any specific case could not be accurately predicted. Conclusions: Quantification of antigens might be useful in evaluating new antigens to target for therapy and may provide a systematic approach to selecting individualized therapy in CLL.