High Progenitor Cell Frequency at Diagnosis Predicts High Minimal residual Disease Level in Childhood ALL.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4705-4705
Author(s):  
Martin Ebinger ◽  
Kai Witte ◽  
Peter J. Lang ◽  
Rupert Handgretinger

Abstract Abstract 4705 Acute lymphoblastic leukemia (ALL) as the most frequent childhood malignancy exhibits a favorable prognosis, yet a significant proportion of patients suffer a relapse. Comparable to acute myeloblastic leukemia, immature leukemic cells may be resistant to therapy and initiate a new population of leukemic cells. 42 patients with childhood ALL treated according to the ALL-BFM 2000 protocol were included in the present study. We determined an aberrant immunophenotype of the leukemic population at diagnosis and investigated the expression of CD34, CD38 and CD45 in leukemic blasts. The fraction of immature leukemic cells defined by CD34+/CD38-/CD45low at time of diagnosis as well as level of minimal residual disease (MRD) at day 33 and day 80 was determined. This is the first study to show a significant correlation of the initial fraction of immature leukemic cells with minimal residual disease levels at day 33 and day 80 in childhood ALL. Thus the initial level of this CD34+/CD38-/CD45low population may serve as marker for adverse prognosis in pediatric ALL. Disclosures: No relevant conflicts of interest to declare.

2003 ◽  
Vol 21 (4) ◽  
pp. 704-709 ◽  
Author(s):  
Glenn M. Marshall ◽  
Michelle Haber ◽  
Edward Kwan ◽  
Ling Zhu ◽  
Daniella Ferrara ◽  
...  

Purpose: A high level of minimal residual disease (MRD) after induction chemotherapy in children with acute lymphoblastic leukemia (ALL) is an indicator of relative chemotherapy resistance and a risk factor for relapse. However, the significance of MRD in the second year of therapy is unclear. Moreover, it is unknown whether treatment intervention can alter outcome in patients with detectable MRD. Patients and Methods: We assessed the prognostic value of MRD testing in bone marrow samples from 85 children at 1, 12, and 24 months from diagnosis using clone-specific polymerase chain reaction primers designed to detect clonal antigen receptor gene rearrangements. These children were part of a multicenter, randomized clinical trial, which, in the second year of treatment, compared a 2-month reinduction-reintensification followed by maintenance chemotherapy with standard maintenance chemotherapy alone. Results: MRD was detected in 69% of patients at 1 month, 25% at 12 months, and 28% at 24 months from diagnosis. By univariate analysis, high levels of MRD at 1 month, or the presence of any detectable MRD at 12 or 24 months from diagnosis, were highly predictive of relapse. Multivariate analysis showed that MRD testing at 1 and 24 months each had independent prognostic significance. Intensified therapy at 12 months from diagnosis did not improve prognosis in those patients who were MRD positive at 12 months from diagnosis. Conclusion: Clinical outcome in childhood ALL can be predicted with high accuracy by combining the results of MRD testing at 1 and 24 months from diagnosis.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4439-4439
Author(s):  
Beata M. Stella-Holowiecka ◽  
Krystyna Jagoda ◽  
Aleksandra M. Holowiecka-Goral ◽  
Tomasz Czerw ◽  
Sebastian Giebel ◽  
...  

Abstract For high-risk adult ALL patients alloHCT is a preferable option. However, a significant proportion of those not having a suitable donor may be successfully treated with autotransplantation (autoHCT). Based on our experience this treatment ensures low transplant related mortality below 3% and a reasonable overall survival and disease free survival of 60% and 45% respectively. The status of the disease before transplantation is an important factor for long term results. In childhood ALL most studies suggest that the level of minimal residual disease (MRD) after induction evaluated immunophenotypically or with bio-molecular methods is predictive for outcome after different treatments including chemotherapy, alloHCT and autoHCT. The results in adult ALL are more controversial. Patients selection. Among 1205 haematopoetic cell transplantations performed in our institution 224 (147 autologous, 77 allogeneic) were performed in 205 adults with ALL. For this study we selected an uniform group of 81 patients fulfilling following criteria’s: Ph (-) ALL, status CR1, evaluable MRD, strictly defined autoBMT procedure performed until the end of 2003. Methods. MRD was tested before autoBMT (median interval 10 days) using 2 ore 3-color flow-cytometry, as appropriate. The atypical immunophenotypes were evaluated using the “quadrans” analysis in all cases and since 2002 also the “empty spaces” technique. The sensitivity equals at least 0.0001. For all autoHSCT bone marrow was used as a source of stem cells. The CAV conditioning regimen consisted of cyclophosphamide 60mg/kg on d. -3, -2, cytarabine 2 g/m2 d. -3, -2, -1, etoposide 800 mg/m2 d. -3, -2. Bone marrow was not cryo-preserved after collection but stored in 40 C and re-transplanted after 72h. Results. In 41 patients; age med. 26 y (15–53), F/M=12/29, the MRD level was <0,001: the MRD (−) group. In 40 patients; age med. 29 y (16–53), F/M=18/22, the MRD was detected at the level =/> 0,001; MRD+ group. The ALL-immunophenotypes of MRD−/MRD+ groups were as follows; proB 4/7, preB 2/6, Common 18/19, B 0/1, preT 5/2, T 12/1). The interval from DGN to BMT was similar in both groups. The probability of LFS and OS at 10y calculated with median follow up time of 5y equaled; in the MRD(−) group 47% and 62% and in the MRD+ one 48% and 57% respectively (p=ns). The main reason of failure in both groups was a relapse which occurred after a median time of 277 days in the MRD(−) group and 134 days in MRD+ one (p=0.19). Conclusion and comment. Based on this observation we conclude that a single evaluation stratifying patients before autoBMT according to MRD level below or above 0.001 is not predictive for DFS and OS, because it informs only about the current amount of the disease but not about its opportunistic nature. In this respect a repeatedly confirmed MRD positivity should be more significant. Taking into consideration that the main reason of failures were relapses, this finding suggests also that in patients with chemotherapy-responsive ALL confirmed by stabile CR, the myeloablative CAV regimen is sufficiently strong to eliminate the residual disease at the level ranging 0.01–0.001. It may be speculated only that the 72h lasting incubation of bone marrow product before re-transplantation has also some kind of purging effect for leukemic blasts.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1521-1521 ◽  
Author(s):  
Mikhail Roshal ◽  
Jonathan Fromm ◽  
Stuart Winter ◽  
Kimberly Dunsmore ◽  
Brent Wood

Abstract Immunophenotyping has become a primary modality in detection of minimal residual disease (MRD) in acute leukemia. Detection and enumeration of leukemic blasts relies on the recognition of the aberrancies in the immunophenotype of the abnormal population. Antigens associated with immature phenotype are thought to represent particularly good markers for identification of leukemic cells. In particular the expression of terminal deoxynucleotide transferase (TdT) on the T-lineage blasts outside the thymus and aberrantly high expression CD99 have been shown to be present in virtually all cases of T-ALL at diagnosis. CD34 and CD10 have also been used as markers of immaturity and aberrancy in MRD. Upon therapy precursor B cell ALL blasts have been shown to lose markers associated with immaturity complicating the detection of MRD. Immunophenotypic changes in T-ALL have not been well characterized. We studied the utility of these markers in the detection of MRD in pediatric patients undergoing chemotherapy under the Children’s Oncology Group (COG) research protocol for treatment of T-ALL. Per protocol (COG-AALL0434) patients received cytarabine intrathecally (IT) on day 1; vincristine IV and daunorubicin hydrochloride IV on days 1, 8, 15, and 22; prednisone IV or orally twice daily on days 1–28; pegaspargase intramuscularly (IM) on day 4, 5, or 6; and methotrexate (MTX) IT on days 8 and 29. Blood and bone marrow samples from 74 consecutive patients enrolled in the protocol between 05/2007 and 04/2008 and who had at least one positive sample (>0.1% blasts of total white cells) at days 8, 15 or 29 post first day of induction were analyzed at diagnosis and in the setting of MRD detection for abnormal expression of TdT, CD99, CD34 and CD10 by multiparameter flow cytometry. Expression of individual antigens was assessed both by percentage of the leukemic blasts with levels of expression above those of normal mature T cells in the samples and by mean fluorescence quotient relative to normal T cells. Consistent with prior reports, nearly all patient samples demonstrated expression of TdT (96%, MFQ=1.35(central 95%=1.01–1.74)) and high expression of CD99 (96%, MFQ=1.34(1.01–1.59)) on at least 20% of abnormal cells at diagnosis. Moreover, TdT and CD99 could be used for blast enumeration with 88% of cases showing greater than 50% positivity for each marker. Expression of these markers began to decline by day 8 and continued to decrease through day 29. Thus only a minority of positive cases showed expression of TdT (24%, MFQ=1.08(0.9–1.62), p<0.001, by Wilcoxon signed-rank test) or CD99 (44%, MFQ=1.14 (0.88–1.51) p<0.001) and in yet smaller proportion of cases could these markers be used for blast enumeration (11% and 26% respectively) by day 29. Median decline for CD99 positivity on the abnormal blasts was 24%, 26% and 62% at day 8, 15 and 29 respectively. Similarly, the differences for TdT were 30%, 44% and 60% respectively. CD34 and CD10 were expressed on a minority of pre-treatment cases (41% and 28% respectively) and expressed similar but less dramatic decline. At day 29, 25.9% of cases expressed CD34 and 16.2% of cases expressed CD10. Median change was 16% for CD34 and 17% for CD10 for cases that expressed those antigens before treatment. Figure 1 demonstrates the declines in both “high positive” with abnormal blasts showing greater than 50% positivity for a marker and of “low positive” cases showing between 20–50% positivity. We conclude that expression of common T-ALL markers of immaturity dramatically declines in the setting of chemotherapy, reducing their value for immunophenotypic detection of MRD. We speculate that this change is due to either chemotherapy induced partial maturation or selective survival of more mature aberrant cells. These results suggest the need for expansion of immunophenotyping panels to decrease reliance on individual markers of immaturity for T-ALL detection in order to achieve a more accurate evaluation of MRD. Figure 1: Loss of markers of immaturity in T-ALL Figure 1:. Loss of markers of immaturity in T-ALL


Hematology ◽  
2012 ◽  
Vol 2012 (1) ◽  
pp. 137-142 ◽  
Author(s):  
Martin Schrappe

Abstract After approximately 20 years of development and after several prospective clinical trials, the detection of minimal residual disease (MRD) has emerged as part of state-of-the-art diagnostics to guide the majority of contemporary treatment programs both in pediatric and adult acute lymphoblastic leukemia (ALL). For ALL, several methods of MRD analysis are available, but 2 are widely applicable. One is based on the detection of aberrant expression of leukemia specific antigens by flow cytometry and the other one uses the specific rearrangements of the TCR or Ig genes, which can be detected by quantitative PCR in the DNA of leukemic cells. In some cases with known fusion genes such as BCR/ABL, RT-PCR can be used as a third method of identifying leukemic cells by analyzing RNA in patient samples. Clinical application of such sophisticated tools in the stratification and treatment of ALL requires reliable, reproducible, and quality-assured methods to ensure patient safety.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2280-2280
Author(s):  
Ulrika Norén-Nyström ◽  
Goran Roos ◽  
Anders Bergh ◽  
Ingrid Thörn ◽  
Gudmar Lonnerholm ◽  
...  

Abstract Fibrosis may complicate bone marrow (BM) disease and in its advanced stage negatively affect the outcome of the patients due to BM failure, particularly in myeloproliferative disorders. Studies of the potential importance of BM fibrosis are rare in childhood acute lymphoblastic leukemia (ALL). We have previously shown a prognostic impact of BM fibrosis measured as reticulin fibre density (RFD) at diagnosis in childhood ALL. To further investigate the consequence of BM fibrosis in childhood ALL in relation to immunophenotype, cytogenetic findings and minimal residual disease (MRD) we retrospectively evaluated the RFD in 139 diagnostic BM biopsies from patients with a total mean follow up time of five years and eight months from two childhood oncology centers in Sweden. Patients with pre-B-ALL showed a higher mean RFD (19.1%) compared to patients with T-ALL (11.4%, p < 0.001). This was true also when comparing high-risk (HR) pre-B-ALL patients (18.1%) with the T-ALL patients (p = 0.002). RFD correlated inversely with the white blood cell count in the HR group (r = −0.41, p = 0.009), probably reflecting our finding of low degree of fibrosis in T-ALL. The cytogenetic analysis revealed that for patients with a hyperdiploid ALL (modal chromosome number: 51–61, n: 41) in the low-risk (LR) group, mean RFD was higher for relapsed patients (22.6%) compared to patients in continuous complete remission (17.2%, p = 0.019). The probability of disease free survival for the same group using RFD cutoff of 21.1%, representing the upper third of the material, was 85%±8% for patients with hyperdiploid ALL and low RFD compared to 51%±14% for patients with hyperdiploid ALL and high RFD (p = 0.01, Figure 1). Data for 32 of the patients demonstrated an association between high RFD at diagnosis and high minimal residual disease (MRD) on day 29 after start of treatment. Patients with FACS-MRD > 10−3 day 29 displayed higher mean RFD at diagnosis (21.2%) compared to patients with FACS-MRD < 10−3 (16.7%, p = 0.027, Figure 2). When analyzing the PCR-MRD data day 29 the findings were similar. We conclude that RFD is higher in pre-B-ALL compared to T-ALL, that RFD has prognostic impact in LR patients with hyperdiploid ALL and that high RFD at diagnosis is associated to high MRD on treatment day 29. All these findings are to our knowledge novel, suggesting that evaluation of BM fibrosis at diagnosis is a potentially new therapy stratifying factor and support the need of further research on BM fibrosis in childhood ALL and expanded use of BM biopsy at diagnosis. Figure 1 Figure 1. Figure 2 Figure 2.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 544-544 ◽  
Author(s):  
Valentino Conter ◽  
André Schrauder ◽  
Helmut Gadner ◽  
Maria Grazia Valsecchi ◽  
Martin Zimmermann ◽  
...  

Abstract Minimal residual disease (MRD), the most sensitive method to evaluate treatment response, has been adopted to stratify patients in study AIEOP-BFM ALL 2000. To assess whether PCR-MRD levels discriminate outcome in patients classified by WBC count, age at diagnosis, NCI criteria (Standard Risk, SR: WBC < 50,000/cmm and age 1–9 years; High Risk, HR: all others) and TEL/AML1 status. Between 07–2000 and 07–2006, 4,730 Ph-negative patients were enrolled in AIEOP-BFM ALL 2000 study. They were treated with BFM Induction (protocol IA) consolidation (protocol IB), extra-compartment/intensified consolidation (HD-MTX in non-HR patients, blocks in HR patients), reinduction therapy (one or more Protocols II or III), followed by maintainance. BM samples obtained at weeks 5 (Time Point 1, TP1) and 12 (TP2) of induction/consolidation therapy were used for PCR-based MRD analysis of patient specific gene targets. At least 2 sensitive markers (≥ 1 x 10−4) could be determined in 3,707 (78.4%) patients. SR was defined by MRD− at both TP1 and TP2; HR by MRD ≥1x10−3 at TP2; Intermediate Risk (IR): all others. Median follow-up was 3 years; 5-year percent EFS (SE) estimates are given.Patients at MRD-SR, IR or HR had, respectively, an EFS of 93.0 (1.0), 80.5 (1.5) and 43.4 (6.0) in patients with WBC <50,000/cmm vs 90.4 (2.6), 72.4 (3.0) and 47.0 (5.1) in patients with WBC ≥50,000/cmm. Patients at MRD SR, IR or HR had, respectively, EFS of 93.6 (1.0), 80.3 (1.5) and 44.1 (5.4) if aged 1–9 years vs 87.2 (3.4), 73.9 (3.0) and 49.3 (5.2) if aged ≥10 years. Patients at SR by NCI criteria [N= 2,355, EFS of 85.3 (1.0)] were stratified by PCR-MRD as SR (N=1046; 44.4%), IR (N=1198; 50.9%), or HR (N=111; 4.7%). EFS in these subgroups was 93.9 (1.0), 81.3 (1.6) and 43.9 (7.2), respectively (p<0.001). In patients at HR by NCI criteria [N=1,352, EFS of 75.6 (1.6)], 403 (29.8%), 774 (57.3%) and 175 (12.9%) respectively were at SR IR and HR by MRD. EFS was 89.4 (2.2) in MRD SR, 74.7 (2.3) in MRD IR and 47.9 (4.2) in MRD HR patients (p<0.001). Of 3,707 study patients, 3,410 were investigated for TEL/AML1 status: 771 (22.6%) were positive and 2,639 were negative. TEL/AML1+ patients were at SR (N=444; 57.6%) or IR (N=317; 41.1%) or HR (N=10; 1.3%) by PCR-MRD; EFS in this subgroup was 94.4% (1.5), 80% (3.7) and 60% (18.4), respectively (p<0.001). TEL/AML1− patients at SR (N=887; 33.6%) or IR (N=1497; 56.7%) or HR (N=255; 9.7%) had an EFS of 91.6% (1.3), 78.5% (1.4) and 45.7% (4.5), respectively (p<0.001). PCR-MRD in patients treated with BFM-oriented therapy overcomes the prognostic value of “historical” factors such as WBC count, age, NCI criteria or TEL/AML1 status, as it markedly discriminates prognosis within each subgroup defined by these variables. Study design for contemporary risk-directed therapy of childhood ALL should incorporate a technique for MRD determination.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2625-2625
Author(s):  
Martin Stanulla ◽  
Elke Schäffeler ◽  
Silke Pohlschmidt ◽  
Martin Zimmermann ◽  
Anja Möricke ◽  
...  

Abstract Abstract 2625 Poster Board II-601 The thiopurines 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) play an essential role in treatment protocols for acute lymphoblastic leukemia (ALL). Thiopurine methyltransferase (TPMT) is a key enzyme in the metabolism of thiopurines and underlies phenotypically relevant genetic variation. Heterozygotes or homozygotes for TPMT genotypes conferring lower enzyme activity demonstrate thiopurine drug metabolic patterns distinct from those of TPMT wild-type individuals. Underlining its clinical importance, several studies have demonstrated a relationship between low TPMT enzyme activity and thiopurine-associated toxicity as well as decreased relapse risk. Here we report on a prospective evaluation of the role of TPMT genetics for survival and treatment-related toxicity in a cohort of 814 pediatric ALL patients. These 814 patients were initially selected based on availability of DNA and represent 85.1% of the entire patient population (n=956) enrolled in the German-Austrian-Swiss multi-center trial ALL-BFM 2000 from October 1999 to September 2002. Genotyping for TPMT was performed by a denaturing HPLC method and subsequent sequencing of variant alleles using DNA prepared from either leukemic or remission bone marrows. This analysis revealed 755 (92.8%) patients with TPMT wild-type, 55 (6.8%) with a heterozygous, and 4 (0.5%) with a homozygous variant genotype (*2/*3A, *3A/*3A [n=2], *3A/*11), respectively. Genotype frequencies were in Hardy-Weinberg equilibrium. Allele frequencies were as follows: TPMT*1 = 96.12%, TPMT*2 = 0.25%, TPMT*3A = 2.95%, TPMT*3C = 0.56%, TPMT*9 = 0.06%, and TPMT*11 = 0.06%. Patients (n=55) heterozygous for allelic variants of TPMT conferring lower enzyme activity demonstrated significantly better event-free survival (EFS) and a lower relapse rate compared to homozygous wild-type patients (n=755) (six-years pEFS; heterozygotes vs. wild-type, 95% (SE 3%) vs. 84% (SE 1%), p(log-rank) = 0.04; p(point estimate difference) = <0.001, relapse incidence at six years, 4% (SE 3%) vs. 12% (SE 3%), p = 0.07). In a Cox regression analysis, adjusting for sex, age, presenting leukocyte count, immunophenotype and minimal residual disease the effect of TPMT genotype was still detectable, but lost statistical significance (hazard ratio for TPMT heterozygosity = 0.38, p = 0.10). An analysis stratified by minimal residual disease-defined risk groups will be presented. While TPMT heterozygotes did not demonstrate statistically significant differences when their toxicity data collected according to the National Cancer Institute's Common Toxicity Criteria were compared with wild-type patients for 6-MP-containing treatment phases, they had an increased risk of developing hepatic veno-occlusive disease associated with a two-week exposure towards 6-TG given during re-intensification. In conclusion, TPMT genotyping may contribute important information for clinical decision making in childhood ALL that goes beyond the prevention of toxicity in TPMT deficient patients. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2506-2506
Author(s):  
Jean-Pierre Bourquin ◽  
Paulina Mirkowska ◽  
Ester Mejstrikova ◽  
Lucie Slamova ◽  
Tomasz Szczepanski ◽  
...  

Abstract Abstract 2506 Comprehensive identification of leukemia-associated cell surface molecules is required to improve the specificity and sensitivity of flow cytometric analysis of minimal residual disease. A more comprehensive map of leukemia-associated cell surface features could facilitate the selection and subsequent evaluation of new minimal residual disease (MRD) markers as a resource and provide direct cues for new therapeutic targets. Here, we used the chemoproteomic Cell Surface Capturing technology (CSC) to establish a surfaceome map consisting of 807 cell surface detectable proteins detected in an xenograft model derived from diagnostic samples from 19 pediatric patients with acute lymphoblastic leukemia (ALL). Because CSC is based on direct chemical tagging of protein and glycoprotein residues on the surface of living cells, highly viable samples are required to avoid intracellular contaminants. Direct processing of xenograft samples provided optimal conditions for CSC. We included 8 cases with resistant disease based on persistence of minimal residual disease (MRD) during chemotherapy, which represents a group of patients at need for innovative approaches. Comparative analysis of this proteomic dataset showed that CSC recapitulated and expanded the diagnostic immunophenotype of each patient. To select and test for new proteins with potential value for MRD detection within the large set of identified leukemia proteins, the dataset was filtered against gene expression data from sorted populations of the normal human hematopoietic tree according to their relative RNA expression levels in normal hematopoiesis (DMAP, Novershtern et al, 2011, Cell, 144, 296–309). Based on expected low levels of mRNA expression in normal early and late B-cell precursors in the bone marrow, a subset of markers was identified. These included cell surface features that were previously implicated in leukemogenesis, such as IL7R or FLT3, or shown to serve as diagnostic markers for flow cytometry such as CD58, CD99 and CD300A. For a first clinical validation phase, we selected 38 markers based on their frequency in the CSC dataset to evaluate whether they could contribute to a better distinction of leukemic blasts from their normal counterparts. We tested monoclonal antibodies that were available for 15 candidate markers on diagnostic and remission samples from ALL patients for relevant expression on leukemia cells. Data is currently available for 9 markers that were evaluated prospectively on 51 patients enrolled in current clinical treatment protocols. All markers detected leukemia-associated features in at least a subset of the patients. As anticipated, differences in antigen abundance and antigenic shifts under treatment varied from case to case, underscoring the advantage of increasing the number of available markers for MRD detection. Taken together, our surfaceome data provides an unprecedented view at the cell surface landscape of ALL cells including new prequalified candidate MRD markers, which will accelerate the introduction and subsequent evaluation of multiple parameters for leukemia diagnostics. This also constitutes a valuable resource for functional studies and evaluation of new options for therapeutic targeting. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2003 ◽  
Vol 102 (13) ◽  
pp. 4520-4526 ◽  
Author(s):  
Aihong Li ◽  
Jianbiao Zhou ◽  
David Zuckerman ◽  
Montse Rue ◽  
Virginia Dalton ◽  
...  

AbstractImmunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements provide clonal markers useful for diagnosis and measurement of minimal residual disease (MRD) in acute lymphoblastic leukemia (ALL). We analyzed the sequences of Ig and TCR gene rearrangements obtained at presentation and relapse in 41 children with ALL to study clonal stability, which has important implications for monitoring MRD, during the course of the disease. In 42%, all original Ig and/or TCR sequences were conserved. In 24%, one original sequence was preserved but the other lost, and in 14% the original sequences were conserved with new sequences identified at relapse. In 20% only new sequences were found at relapse. Using primers designed from the novel relapse sequences, the relapse clone could be identified as subdominant clones in the diagnostic sample in 8 of 14 patients. Alteration of these clonal gene rearrangements is a common feature in childhood ALL. MRD detection should include multiple gene targets to minimize false-negative samples or include also multicolor flow cytometry. In some cases the leukemic progenitor cell might arise earlier in lineage before DHJH recombination but retain the capacity to further differentiate into cells capable of altering the pattern of Ig and/or TCR rearrangements. (Blood. 2003;102:4520-4526)


2021 ◽  
Vol 10 ◽  
Author(s):  
Yu Wang ◽  
Yu-Juan Xue ◽  
Yue-Ping Jia ◽  
Ying-Xi Zuo ◽  
Ai-Dong Lu ◽  
...  

PurposeWhile the role of minimal residual disease (MRD) assessment and the significance of achieving an MRD-negative status during treatment have been evaluated in previous studies, there is limited evidence on the significance of MRD re-emergence without morphological relapse in acute lymphoblastic leukemia (ALL). We sought to determine the clinical significance of MRD re-emergence in pediatric ALL patients.MethodsBetween 2005 and 2017, this study recruited 1126 consecutive patients newly diagnosed with ALL. Flow cytometry was performed to monitor MRD occurrence during treatment.ResultsOf 1030 patients with MRD-negative results, 150 (14.6%) showed MRD re-emergence while still on morphological complete remission (CR). Patients with white blood cell counts of ≥50 × 109/L (p = 0.033) and MRD levels of ≥0.1% on day 33 (p = 0.012) tended to experience MRD re-emergence. The median re-emergent MRD level was 0.12% (range, 0.01–10.00%), and the median time to MRD re-emergence was 11 months (range, &lt;1–52 months). Eighty-five (56.6%) patients subsequently developed relapse after a median of 4.1 months from detection of MRD re-emergence. The median re-emergent MRD level was significantly higher in the relapsed cohort than in the cohort with persistent CR (1.05% vs. 0.48%, p = 0.005). Of the 150 patients, 113 continued to receive chemotherapy and 37 underwent transplantation. The transplantation group demonstrated a significantly higher 2-year overall survival (88.7 ± 5.3% vs. 46.3 ± 4.8%, p &lt; 0.001) and cumulative incidence of relapse (23.3 ± 7.4% vs. 64.0 ± 4.6%, p &lt; 0.001) than the chemotherapy group.ConclusionsMRD re-emergence during treatment was associated with an adverse outcome in pediatric ALL patients. Transplantation could result in a significant survival advantage for these patients.


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