scholarly journals rt-PCR method for diagnosis and follow-up of hematological malignancies: First approach in Bangladesh

2008 ◽  
Vol 34 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Tanvira Afroze Sultana ◽  
Md. Abdul Mottalib ◽  
Md. Sirazul Islam ◽  
Mohiuddin Ahmed Khan ◽  
Subhagata Choudhury
Keyword(s):  
Hematological Malignancies ◽  
Residual Disease ◽  
Strong Positive Correlation ◽  
Rt Pcr ◽  
Duration Of Treatment ◽  
All Trans Retinoic Acid ◽  
Pcr Method ◽  
First Time ◽  
Positive Results

Nested reverse-transcriptase polymerase chain reaction (rt-PCR) was performed on 58 leukemia patients at BIRDEM Laboratory, as a pioneering work in Bangladesh. Thirty of them were examined for the presence of BCR-ABL being clinically and morphologically diagnosed as chronic myeloid leukemia (CML) and 28 for PML-RARα fusion transcripts being clinically and morphologically diagnosed as acute promyelocytic leukemia (APL/ AML M3). The cases were selected for targeted therapy with imatinib mesylate and all-Trans retinoic acid (ATRA) to treat CML and APL respectively. Samples were received either before commencement or during therapy. In the positive cases, amplified DNA products were visible after gel electrophoresis and were reported accordingly. In case of BCR-ABL, positive results were found for five out of six (83.33%) untreated cases and 11 out of 24 (45.83%) treated cases. Positive results for PML-RARα were found for 12 out of 14 (85.70%) untreated cases and 11 out of 16 (68.75%) treated cases. A strong positive correlation was found between duration of treatment and negativity of PCR results in both the cases. In present times, the detection of minimal residual disease in patients undergoing treatment for hematological malignancies has become an important goal, not only to monitor the effectiveness of therapy but also to detect an impending relapse. This is the first time in Bangladesh that rt-PCR method is being employed to detect or monitor the presence of abnormal fusion genes in hematological malignancies. Keywords: Bangladesh; malignancy; rt-pcrDOI: 10.3329/bmrcb.v34i1.1162Bangladesh Med Res Counc Bull 2008; 34: 1-11

scholarly journals SARS-CoV-2 re-positivity within the first 3 months of COVID-19 recovery; probable re-infection

2021 ◽  
Author(s):  
sara sadr ◽  
Melika Arab Bafrani ◽  
Alireza Abdollahi ◽  
SeyedAhmad SeyedAlinaghi ◽  
Esmaeil Mohammadnejad ◽  
...  
Keyword(s):  
Herd Immunity ◽  
Rt Pcr ◽  
Complete Protection ◽  
Genetic Sequencing ◽  
Serum Igg ◽  
Follow Up Studies ◽  
Positive Results

Objectives Possibility of reinfection with SARS-CoV-2 changes our view on herd immunity and vaccination, and can impact worldwide quarantine policies. We performed RT-PCR follow-up studies on recovered patients to assess possible development of reinfections and re-positivity. Method During a 6-month period, 202 PCR-confirmed recovering COVID-19 patients entered this study. Follow-up RT-PCR tests and symptoms assessment were performed one month after the initial Positive results. patients who tested negative were tested again one and three months later. The Serum IgG and IgM levels were measured in the last follow-up session. Results In the first two follow-up sessions, 82 patients continued their participation, of which four patients tasted positive. In the second follow-up 44 patients participated, three of whom tested positive. None of the patients who tested positive in the first and second follow-up session were symptomatic. In the last session, 32 patients were tested and four patients were positive, three of them were mildly symptomatic and all of them were positive for IgG. Conclusion A positive RT-PCR in a recovering patient may represent reinfection. While we did not have the resources to prove reinfection by genetic sequencing of the infective viruses, we believe presence of mild symptoms in the three patients who tested positive over 100 days after becoming asymptomatic, can be diagnosed as reinfection. The IgG may have abated the symptoms of the reinfection, without providing complete protection.

First Complete Genome of Lake Sinai Virus Lineage 3 and Genetic Diversity of Lake Sinai Virus Strains From Honey Bees and Bumble Bees

2020 ◽  
Vol 113 (3) ◽  
pp. 1055-1061 ◽  
Author(s):  
Laura Šimenc ◽  
Urška Kuhar ◽  
Urška Jamnikar-Ciglenečki ◽  
Ivan Toplak
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Complete Genome ◽  
Bumble Bees ◽  
Bumble Bee ◽  
Rt Pcr ◽  
Genome Region ◽  
Pcr Method ◽  
Next Generation Sequencing Ngs ◽  
First Time

Abstract The complete genome of Lake Sinai virus 3 (LSV3) was sequenced by the Ion Torrent next-generation sequencing (NGS) technology from an archive sample of honey bees collected in 2010. This strain M92/2010 is the first complete genome sequence of LSV lineage 3. From October 2016 to December 2017, 56 honey bee samples from 32 different locations and 41 bumble bee samples from five different locations were collected. These samples were tested using a specific reverse transcriptase-polymerase chain reaction (RT-PCR) method; 75.92% of honey bee samples and 17.07% of bumble bee samples were LSV-positive with the RT-PCR method. Phylogenetic comparison of 557-base pair-long RNA-dependent RNA polymerase (RdRp) genome region of selected 23 positive samples of honey bees and three positive bumble bee samples identified three different LSV lineages: LSV1, LSV2, and LSV3. The LSV3 lineage was confirmed for the first time in Slovenia in 2010, and the same strain was later detected in several locations within the country. The LSV strains detected in bumble bees are from 98.6 to 99.4% identical to LSV strains detected among honey bees in the same territory.

Minimal Residual Disease (MRD) Analysis in Acute Myeloid Leukemia (AML) with Favorable Cytogenetics [t(8;21) and inv(16)] by Real Time PCR(RT-PCR) and Flow Cytometry (FC).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2989-2989
Author(s):  
Granada Perea ◽  
Adriana Lasa ◽  
Anna Aventin ◽  
Alicia Domingo ◽  
Neus Villamor ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Residual Disease ◽  
Fusion Transcript ◽  
Good Prognosis ◽  
Rt Pcr ◽  
Free Survival ◽  
End Of Treatment ◽  
The Mean ◽  
Minimal Residual

Abstract Objectives: To analyze MRD in 65 patients (pts) with good prognosis AML: 30 t(8;21) and 35 inv(16), using both FC and RT-PCR, and to investigate the prognostic value of MRD in the pts outcome. Methods: MRD was monitored in CR pts (n=55) by FC in 101 follow-up samples obtained after various cycles of treatment, as follows: 40 post-induction (ind), 30 post-intensification (int) and 31 at the end of treatment (ttm), and by RT-PCR in 76 samples: 31, 23 and 22, respectively. In 35 pts the two techniques were applied at the same time of the ttm. MRD by FC was assessed using fixed combinations of three monoclonal antibodies. AML1/ETO and CBFb/MYH11 were analyzed following the BIOMED protocol. Results: Twenty-seven percent (n=15) of CR pts relapsed: 6 with t(8;21) and 9 with inv(16). The mean MRD by FC was 1.1% after ind, 0.2% after int and 0.1% at the end of ttm. At the end of ttm, the MRD detected by FC in relapsed and not relapsed pts were significativaly different: 0.3% vs 0.08% (p=0.002). By RT-PCR, the mean of fusion transcript copies/ablx104 differed between relapsed and nonrelapsed pts: 2385 vs 122 (p=0.001) after ind, 56 vs 7.6 after int (p=0.0001) and 75 vs 3.3 (p=0.0001) at the end of ttm. Relapses were more commonly observed in those pts with FC MRD level >0.1% at the end of ttm than in pts with ≤0.1%: 50% vs 12% (p=ns); likewise, using RT-PCR, a cutoff level of >10 copies at the end of ttm correlated with high risk of relapse: 80% of pts with RT-PCR >10 relapsed compared to 12% of pts with levels <10 (p=0.009). The overall survival (OS) probability was 86% for pts with CF MRD ≤0.1 at the end of ttm and 0% for pts with MRD >0.1 (p=0.1) and the leukemia free survival (LFS) was 78% and 44%, respectively (p=0.05). For pts with RT-PCR ≤10 at the end of ttm, the OS was 100% and for pts with RT-PCR >10 it was 30% (p=0.007) and the LFS was 87% and 20%, respectively (p=0.001). MRD was identified after ind in 55% of relapsed pts and at the end of ttm in 83% of relapsed pts. Only 1 pt (1/13) with FC MRD <0.1 and RT-PCR <10 at the end of ttm relapsed. For patients in complete remission, the mean copy level of chimeric transcript was higher for pts with t(8;21) than for those with inv(16): 30.2 vs 17.4 (p=0.0001). Comments: In tandem analysis of MRD by FC and RT-PCR could improve MRD detection in AML pts.

Molecular Remission to Imatinib in Patients with Chronic Myeloid Leukaemia (CML) Is Less Durable Compared to Patients after Allografting.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 276-276
Author(s):  
Thoralf Lange ◽  
Thomas Bumm ◽  
Marc Mueller ◽  
Sandra Otto ◽  
Haifa K. Al-Ali ◽  
...  
Keyword(s):  
Nested Pcr ◽  
Bone Marrow Cells ◽  
Residual Disease ◽  
Standard Dose ◽  
Healthy Individuals ◽  
Rt Pcr ◽  
Molecular Remission ◽  
Conventional Cytogenetics ◽  
Risk Of Relapse

Abstract Objectives: Patients with CML who achieve molecular remission (MR, defined as a RT-PCR negativity for BCR-ABL transcripts) after myeloablative stem cell transplantation (SCT) have a low risk of relapse, and the majority may be cured. The frequency of MR on imatinib varies greatly and the durability of these responses has not been reported. To investigate if MR after SCT and on imatinib are equally stable, we directly compared two cohorts of patients treated with imatinib or SCT, respectively, from the time of their first negative RT-PCR result. Patients and Methods: One hundred and forty-four CML patients in chronic (n=104) or accelerated phase (n=40) treated with standard dose imatinib were routinely monitored by conventional cytogenetics, quantitative RT-PCR (qPCR) and conventional nested PCR in case of negative qPCR results. Nineteen patients (13.2%) had at least 1 negative nested PCR. To assess the level of residual disease in patients with a single negative RT-PCR result, 10 replicate reactions were performed, each corresponding to &gt; 106 white bone marrow cells. Thirty-six samples (median 3, range 1–4) from patients in MR on imatinib and 45 samples (median 2, range 1–3) from patients in MR after SCT were available. Twenty samples from healthy individuals were tested as controls. Results: The first negative result was noted after a median of 16.8 months (range 11.5–36.1) of imatinib therapy and 6.6 months (range 4.7–9.5) after SCT, respectively. The projected risk of molecular relapse at 12 months after the first negative RT-PCR result was 83% in patients on imatinib but only 20% in patients after SCT (P = 0.0001). Only two patients on imatinib remained in molecular remission at 13.8 and 16.6 months. While none of the patients with molecular relapse after allograft lost CCyR, one patient on imatinib progressed to cytogenetic relapse. The replicate assay was positive in 18/36 samples (50%) from patients on imatinib, 8/46 (17.4%) after allografting and 4/20 (20%) from healthy individuals. These differences were significant between patients on imatinib and after allografting (P = 0.003) and between patients on imatinib and healthy individuals (P = 0.005), but not between patients after allografting and healthy individuals (P = 0.9). Negativity by replicate testing was more stable in patients after allografting, although, even in these patients, positive replicate reactions continued to occur with longer follow-up. Conclusion: Imatinib-induced MR is usually not durable, in contrast to MR after transplant. Consistent with this, the level of residual disease in samples negative by single nested PCR is higher in patients on imatinib compared to patients after SCT. These results suggest that disease eradication with imatinib monotherapy may be rare. Patients on imatinib followed by PCR should be made aware of the fact that a single negative test does not have the same significance as in patients after SCT.

Molecular Response of CML Patients to INFα Based Treatment or to STI Based Therapy.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4872-4872
Author(s):  
Debora Luzi ◽  
Rosanna Capozzi ◽  
Annamaria Rauco ◽  
Roberta Pace ◽  
Emilio Donti ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Response Duration ◽  
Cytogenetic Response ◽  
The Other ◽  
Entire Group ◽  
Molecular Response ◽  
Rt Pcr ◽  
Molecular Remission ◽  
First Time

Abstract Introduction: Continous improving results have been obtained during last two decades in the control of Ph’positive chronic myeloid leukemia(CML). However the final goal of molecular remission remains difficult to obtain even in the STI age. Aims : Evaluation of the rate of molecular response to IFNα,IFNα based treatment,to STI or to STI-INFα combination was analized in 100 consecutive Ph+ CML patients observed in a single Institution over a period of 20 years. Patients, Methods and Results All patients were treated at the time of diagnosis (87) or late (13) during the course of their disease. Distribution according to treatment was: INFα,63pts (late or early:13,50);INFα-ARA-C combination,20pts;STI,14 pts;STI-INFα association, 3 pts. Two pts, both initially assigned to INFα-ARA-C combination, were crossed-over to STI, one because relapsing off-therapy after a long lasting continous (25 mths) molecular remission and the other in cytogenetic response because intolerant to the initial treatment. In addition, other 3 pts patients, with persistent complete cytogenetic, but not molecular remission to INFα or INFα-ARA-C combination were subsequentially trated with the STI-IFNα association. At present,99/100 pts are evaluable. The median times of follow-up for the entire group and form the different treatment subgroups are: late IFNα 154 months(42–263); early IFNα, 71 months(1–197); IFNα-ARA-C, 61 months(5–203); STI- IFNα,78 mths(11–47), STI,31 mths(3–41). A complete kariotypic remission(CKR) was observed in 15/63 IFNα treated pts, in 10/20 IFNα-ARA-C pts group, in 10/13 cases of STI group and in 3 /3 pts who received STI-IFNα. A molecular response(RT-nested PCR, JQ Guo, Leukemia: 2002,15,2447–53) was observed in 4/15,2/10,5/10 and in 2/3 CKR pts initially trated with the different modalities listed above. Response was confirmed from 2 to 7 consecutive or not consecutive times in the 2/4 cases responsive to INFα, in the 2 cases responsive to INFα-ARA-C combination,4/5cases responsive to STI and in 2/3 cases responsive to STI-IFNα association. The 2nd and the 3rd molecular remission to STI were obtained in the patient molecularly and cytogenetically relapsed off-therapy and, for the first time from the diagnosis, in the other patient in CKR to IFNα-ARA-C combination and crossed to STI treatment. Furthermore, all 3 cases, in CKR, but not molecular response to other treatments at the time of cross-over to STI-IFNα combination, achieved a persistent (in 2 to 3 tests over a period ranging from 6+ to 12+ mths) molecular remission. The first interval between the start of the treatment and the first molecular response varied from 12 to 52, from 3 to 22, from 11 to 24, from 5 to 11 mths in the groups initially treated with IFNα, IFNα-ARA-C, STI or STI-IFNα respectively. The 2 pts, crossed-over to STI alone, both, obtained a response after 29 mths of therapy. In addition in the 3 pts crossed-over to STI-IFNα therapy, the molecular response was obtained after 14,23 and 25 mths from the start of last treatment. Conclusion It is not possible to achieve any conclusion regarding the treatment effect on molecular response duration because of the different length of follow-up of various groups of patients. However in responsive patients to IFN alone or combined to ARA-C or STI, consecutive negative RT-PCR tests were observed more frequently than in patients receving STI alone.

Quantitative Monitoring of NPM1 Mutation A Minimal Residual Disease Identifies Patients At High Risk for Relapse within the ELN Favorable Risk Group

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1404-1404
Author(s):  
Max Hubmann ◽  
Marion Subklewe ◽  
Thomas Köhnke ◽  
Stephanie Schneider ◽  
Annika Dufour ◽  
...  
Keyword(s):  
High Risk ◽  
Induction Therapy ◽  
Residual Disease ◽  
Risk Group ◽  
Disease Recurrence ◽  
Consolidation Therapy ◽  
Rt Pcr ◽  
Npm1 Mutation ◽  
Minimal Residual

Abstract Abstract 1404 Introduction: Molecular analyses of leukemia-specific markers has led to an improvement of the prognosis evaluation in patients (pts) with acute myeloid leukemia (AML). The European Leukemia Net (ELN) has published a classification which separates different subgroups by cytogenetic and molecular genetic analyses. Nevertheless, there are still pts suffering from disease recurrence within the ELN favorable risk group. To identify these pts at high risk for relapse the monitoring of minimal residual disease (MRD) of leukemia-specific markers could become an important diagnostic tool. In this study the potential of MRD monitoring by quantitative real-time PCR (RT-PCR) of NPM1 A mutation (NPM1 A) at different checkpoints within the ELN favorable risk group of pts with NPM1 A and without FLT3-ITD was investigated. Methods: Pts participating in the AMLCG99, AMLCG2004, and AMLCG2008 trial were prospectively or retrospectively screened for NPM1 mutation and FLT3-ITD by melting curve analyses. 334 pts were screened positive for NPM1 mutation and 262 pts showed a NPM1 A, 78.4 % of all NPM1 mutations. For MRD monitoring a relative RT-PCR was performed in 538 samples of 178 NPM1 A positive pts with a sensitivity of 10-6. MRD was monitored at diagnosis, in aplasia, after induction therapy, after consolidation therapy, and during the follow-up. MRD levels were normalized to the housekeeping gene ABL1 and expressed as a ratio to an internal control of known concentration. Results: In the analysis of the NPM1 A positive and FLT3-ITD negative pts (ELN favorable risk group) 82.5% (n=85) achieved complete remission (CR) after induction therapy. With a median follow-up of 26 (range 1–118) months, 36 (42.9%) pts relapsed within this subgroup. In aplasia, and after induction therapy, pts with a long-lasting remission showed significantly lower NPM1 A ratios in contrast to pts who relapsed during the follow-up. Via Receiver-Operating Curves (ROC) we analyzed the diagnostic power to identify pts at high risk for relapse and determined clinical useable cut-offs at the different checkpoints. ROC were significantly associated with disease recurrence at the checkpoints in aplasia and after induction therapy, but not after consolidation therapy. After induction therapy, a cut-off with a ratio of 0.01 was determined. This cut-off separates the patient cohort into two prognostic groups. NPM1 A MRD levels above the cut-offs result in an increased risk of relapse compared to pts with MRD level below this cut-off. This is reflected in a significantly lower 2-year relapse free survival (RFS) of 18% versus 72% (Figure 1). In 25 pts of this favorable risk group follow-up samples in CR were available for analysis of an upcoming relapse within 100 days of sampling. Only 2 of these pts developed relapse within of the next 100 days, but both pts showed increasing MRD levels prior to relapse. 18 relapse samples were available in this subgroup and interestingly, one patient (5.5%) was NPM1 A negative at relapse. When we further enrolled the FLT3-ITD positive pts into our analyses, not surprisingly we found a negative impact on the RFS of MRD positive and MRD negative pts. Conclusions: Our results confirm the observations of other studies that showed the prognostic impact of NPM1 MRD monitoring by RT-PCR. With the MRD monitoring we could identify pts at high risk for relapse within the ELN favorable risk group. Particularly high MRD levels after the induction therapy were strongly associated with a worse RFS. This and previously published data of others demonstrate that in addition to pre-therapeutic factors, the individual MRD course should be used as prognostic factor for the guidance of treatment and pts with high or increasing levels of MRD should undergo allogeneic stem cell transplantation, if eligible. Disclosures: No relevant conflicts of interest to declare.

Minimal Residual Disease Monitored With Fluorescence In Situ Hybridization (FISH) In CD34+CD38- Population Predicts Clinical Outcome In Core Binding Factor Acute Myeloid Leukemia (CBF-AML)

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1356-1356
Author(s):  
Xiaoxia Hu ◽  
Libing Wang ◽  
Lei Gao ◽  
Sheng Xu ◽  
Shenglan Gong ◽  
...  
Keyword(s):  
Minimal Residual Disease ◽  
Myeloid Leukemia ◽  
De Novo ◽  
Residual Disease ◽  
Consolidation Therapy ◽  
Rt Pcr ◽  
Binding Factor ◽  
Minimal Residual

Abstract Acute myeloid leukemia (AML) is generally regarded as a stem cell disease, known as leukemic initiating cells (LIC), which initiate the disease and contribute to relapses. Although the phenotype of these cells remains unclear in most patients, they are enriched within CD34+CD38- compartment. In core binding factor (CBF) AML, the cytogenetic abnormablities are also existed in LIC. The aim of this study was to determine the prognostic power of minimal residual disease measured by fluorescence in situ hybridization (FISH) in flow sorted CD34+CD38- cells (FISH+CD34+CD38- population) at different period during the therapy. Thirty-six patients under 65 years of age with de novo CBF AML and treated with CHAML 2010 protocol were retrospectively included in this study. FISH efficiently identified the LICs (FISH+CD34+CD38-) in the CD34+CD38- population. The last follow-up was March 31, 2013, and the median follow-up was 336 days (range: 74-814 days). 33 patients with complete remission (CR) were eligible for the study, and 23 patients (23/33, 69.7%) with t (8;21) or AML1/ETO, and the remaining (10/33, 30.3%) with inv(16)/t(16;16) or CBFβ/MYH11. Flow-cytometry based FISH (F-FISH) procedure was performed at diagnosis, before every cycle of consolidation therapy, and every 3 months during follow-up. The FISH+ percentage at diagnosis constituting an average of 2.1% (range: 0.01%-27.5%) of the blast cells and 64.6% (range: 14%-87.8%) of the CD34+CD38- cells. Before the consolidation, FISH+CD34+CD38- population was detected in 13/33 (39.4%) patients. At this checkpoint, we have found the existence of FISH+CD34+CD38- population had prognostic value for the end points relapse free survival (RFS, 12% versus 68%, P=.008), and retained prognostic significance for RFS in multivariate analysis. Furthermore, the detection of FISH+CD34+CD38- before consolidation was found to be significantly associated with decreased OS. (11% versus 75%, P=.0005) Minimal residual disease (MRD) detected with F-FISH had a prognostic value at an earlier checkpoint when compared with flow cytometry and RT-PCR. Meanwhile, the concordance of flow cytomety, RT-PCR and F-FISH was investigated in the same patient cohort. 14 (70%) of 20 samples with detectable fusion transcripts by PCR did not have detectable leukemic cells by F-FISH. Therefore, the concordance for PCR and F-FISH was 63.7%. The concordance of FC and F-FISH was 64.3%: in 40 samples MRD was detected by both methods and in 61 samples MRD was ruled out by a negative result with the tests. With further analysis, the discrepancies among MRD detected with different MRD monitoring approaches before consolidation and after the first consolidation therapy contribute to 84% of the disconcordance. In summary, the detection of FISH+CD34+CD38- cells before consolidation therapy was significantly correlated with long-term survival in de novo CBF AML patients. F-FISH might be easily adopted as MRD monitor approach in clinical practice to identify patients at risk of treatment failure from the early stage during therapy. Disclosures: No relevant conflicts of interest to declare.

Prognostic significance of minimal residual disease detection and PML/RAR-α isoform type: long-term follow-up in acute promyelocytic leukemia

Blood ◽  
2001 ◽  
Vol 98 (9) ◽  
pp. 2651-2656 ◽  
Author(s):  
Joseph G. Jurcic ◽  
Stephen D. Nimer ◽  
David A. Scheinberg ◽  
Tony DeBlasio ◽  
Raymond P. Warrell ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Acute Promyelocytic Leukemia ◽  
Residual Disease ◽  
Prognostic Significance ◽  
Promyelocytic Leukemia ◽  
Newly Diagnosed ◽  
Rt Pcr ◽  
Pcr Assays

Abstract The t(15;17) translocation in acute promyelocytic leukemia (APL) yields a PML/RAR-α fusion messenger RNA species that can be detected by reverse transcription–polymerase chain reaction (RT-PCR) amplification. Breakpoints within intron 3 of PML produce a short PML/RAR-α isoform, whereas breakpoints within intron 6 result in a longer form. Using RT-PCR, serial evaluations were performed on the bone marrow of 82 patients with APL (median follow-up, > 63 months) who received retinoic acid (RA) induction followed by postremission treatment with chemotherapy, RA, and biologic agents. Sixty-four patients attained a clinical complete remission and had at least 2 RT-PCR assays performed after completing therapy. Forty of 47 patients (85%) with newly diagnosed APL who were induced using RA had residual disease detectable by RT-PCR before additional therapy. After 3 cycles of consolidation therapy, residual disease was found in only 4 of 40 evaluable patients (10%). Among newly diagnosed patients who had 2 or more negative RT-PCR assays, only 3 of 41 (7%) had a relapse, whereas all 4 patients (100%) who had 2 or more positive results had a relapse. Among 63 newly diagnosed patients, those who expressed the short isoform appeared to have shorter disease-free and overall survival durations than patients who expressed the long isoform. These data indicate that 2 or more negative RT-PCR assays on bone marrow, performed at least 1 month apart after completing therapy, are strongly associated with long-term remissions. Conversely, a confirmed positive test is highly predictive of relapse.

Comparison Between RT-PCR and RQ-PCR for Minimal Residual Disease Detection in Acute Promyelocytic Leukemia: The International Consortium on Acute Promyelocytic Leukemia (IC-APL) Experience,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3552-3552
Author(s):  
Ana Paula Alencar de Lima Lange ◽  
Ana Sílvia Gouvea Lima ◽  
Rafael Henriques Jacomo ◽  
Raul AM Melo ◽  
Rosane Bittencourt ◽  
...  
Keyword(s):  
Minimal Residual Disease ◽  
Acute Promyelocytic Leukemia ◽  
Residual Disease ◽  
Fusion Transcript ◽  
Promyelocytic Leukemia ◽  
Rt Pcr ◽  
International Consortium ◽  
The Third ◽  
Minimal Residual

Abstract Abstract 3552 The International Consortium on Acute Promyelocytic Leukemia (IC-APL) is an initiative of the International Members Committee of the ASH that aims to improve the treatment outcome of acute promyelocytic leukemia (APL) patients in developing countries, which was launched in Mexico, Brazil, Chile and Uruguay. The protocol is identical to the PETHEMA-LPA2005, except for the replacement of idarubicin by daunorubicin. In our interim analysis, estimated 2-year overall and disease-free survivals are 80% and 90%, respectively. The 2-year cumulative incidence of relapse was 5.6%. The median follow-up among survivors was 23 months (range: 1 – 56 months). A secondary aim of IC-APL was to establish molecular monitoring for minimal residual disease (MRD) as a standard practice for APL patients in these countries and to use the results obtained to guide therapy. According to the IC-APL protocol, testing for the PML-RARA fusion transcript was to be performed at diagnosis, end of induction (optional), after the third cycle of consolidation, and every 3 months during maintenance. Considering that real-time quantitative polymerase chain reaction (RQ-PCR) provides a number of advantages compared to conventional non-quantitative reverse transcriptase PCR (RT-PCR), we retrospectively compared the results obtained by both techniques. We analyzed 400 bone marrow (BM) samples from 97 patients with de novo APL enrolled in the IC-APL protocol in Brazil. Of the 97 patients, 78 were considered eligible. The mean age was of 35.8 years with 46 males. Among eligible patients, 49 corresponded to bcr1 ; one to bcr2 and 28 to bcr3 subtype of PML breakpoint. To quantify the fusion transcript PML-RARA we used standardized assays developed in the Europe Against Cancer (EAC) program, normalized to the expression of the ABL gene. The results were compared to plasmid standards (Ipsogen, Marseille) and expressed as Normalized Copy Numbers (NCN). Follow-up samples were considered PCR positive when PML-RARA transcripts amplified with Cycle Threshold (Ct) values of ≤40 in at least 2 out of 3 replicates, according to EAC criteria. A total of 71 samples at diagnosis, 50 at the end of induction, 47 after the third consolidation, 202 during maintenance phase and 30 samples after completion of treatment were analyzed. The median NCN of PML-RARA transcripts at diagnosis was 0.5151 and 0.5092 for the bcr1 and bcr3 subtypes, respectively. At the end of induction there was a reduction of about 3 logs (0.0004 for bcr1 and 0.0005 for bcr3). In this phase, six discrepant cases were observed, all presenting positivity by RQ-PCR. None of these cases relapsed and presented consecutive negative results. Considering samples obtained at the end of consolidation, we detected one case of molecular persistence detected by both methods, and two discrepant results, one positive by RT and another by RQ-PCR. Both cases did not relapse. Among samples collected during maintenance and after the end of treatment, two patients (2.5%) relapsed. Both of them were molecular relapses, defined as the detection (in the context of morphological remission) of the PML-RARA transcript by RT-PCR in two consecutive samples collected 15 days apart. RQ-PCR analysis provided much earlier warning of recurring disease, testing positive 5 and 6 months, respectively, before documentation of molecular relapse by conventional RT-PCR assay. Figure 1 show the kinetics of NCN in these two cases. Our results reinforce that the PML-RARA transcript may be detected after induction but this finding was not of prognostic value. However, our study underlines the importance of sequential monitoring to distinguish patients likely to be cured following front-line therapy from those destined to relapse. The RQ-PCR technique was shown to be more sensitive than RT-PCR, providing earlier warning of impending relapse, thereby allowing greater opportunity for successful delivery of pre-emptive therapy. Finally, our results demonstrate that the implementation of the IC-APL allowed the improvement of laboratory standards in parallel to advances in clinical management. Disclosures: Pasquini: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol Myers Squibb: Speakers Bureau. Pagnano:Novartis: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau.

Droplet Digital PCR Analysis for Diagnosis and Minimal Residual Disease Monitoring in Adult Ph+ Acute Lymphoblastic Leukemia

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4989-4989 ◽  
Author(s):  
Nicoletta Coccaro ◽  
Antonella Zagaria ◽  
Luisa Anelli ◽  
Giuseppina Tota ◽  
Paola Orsini ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Residual Disease ◽  
Lymphoblastic Leukemia ◽  
Fusion Transcript ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Pcr Analysis ◽  
Rt Pcr ◽  
Minimal Residual

Abstract Introduction. BCR-ABL1 tyrosine kinase inhibitors (TKIs) are considered an important component of treatment for adult patients affected by Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). In fact, recent studies reported that treating Ph+ ALL with the combination of imatinib and multi-agent chemotherapy improved the overall outcome. Currently, no data are available on the impact of TKIs on minimal residual disease (MRD) in Ph+ ALL. In fact, although the real-time quantitative PCR (RQ-PCR) method, usually employed for monitoring the BCR-ABL1 residual transcript, is sensitive and easy to perform, it lacks a full standardization and international quality validation. Here, we describe a highly sensitive and reproducible droplet digital PCR (ddPCR) test to monitor BCR-ABL1 transcript level in Ph+ ALL. Methods. BCR-ABL1 expression analysis by ddPCR was performed in twenty-two newly diagnosed adult Ph+ ALL patients.The diagnosis was confirmed by qualitative RT-PCR specific for the BCR-ABL1 p190 fusion gene detection. ddPCR experiments were successfully performed in all twenty-two patients at the onset; several follow-up points were evaluated in thirteen patients. ddPCR experiments were performed using primers and probes specific for BCR-ABL1 p190. GUSB was used as control gene. Fifty ng and 750 ng of cDNA templates were used for the onset and for the post-treatment samples, respectively. To increase the limit of detection (LOD), three replicates were run for the post-treatment samples. ddPCR experiments were performed by Bio-Rad's QX200 system and ddPCR data were analyzed with QuantaSoft analysis software (version 1.7.4). Target concentration was expressed as BCR-ABL1 copies/mg. Results. First, we defined the LOD of the BCR-ABL1 p190 ddPCR system, a 10-fold dilution series (100, 10-1, 10-2, 10-3, 10-4, and 10-5) of a pool of p190 positive patients using a diluent-pool of healthy volunteers. This analysis showed remarkable linearity, trueness, and precision down to 10-5. After converting to log-log scale, linear regression showed no concentration-dependent bias, and R2 equaled 0.996. Because the negative samples showed no background, even the detection of a single droplet per well was considered a positive result. The median concentration of the BCR-ABL1 transcript at the onset was 233.8 (min 3.24 - max 1744) x 103BCR-ABL1 copies/mg. Concerning the analysis of follow-up samples, among the thirty-four points that were negative to qualitative nested RT-PCR, twenty-three (68%) resulted to be positive by ddPCR analysis, with a median concentration of 44.95 (min 0.27 - max 573.3) BCR-ABL1 copies/mg. Follow-up points that were negative in ddPCR remained negative even when the experiments were repeated increasing the depth of the analysis, evaluating a total quantity of 4.5 mg of RNA. Conclusions. This study indicates that, as compared to RQ-PCR, ddPCR increases the depth of the quantitative analysis of BCR-ABL1 p190 fusion transcript by allowing the evaluation of larger amounts of RNA. Moreover, our preliminary data revealed that the amount of the BCR-ABL1 fusion transcript at diagnosis is heterogeneous and that the ddPCR is much more sensitive than nested qualitative RT-PCR analysis, as the 68% of samples negative to nested PCR during the follow-up resulted to be positive by ddPCR. Therefore, we suggest that ddPCR represents a precise, sensitive and rapid method for both diagnosis and MRD monitoring of Ph+ ALL patients. Disclosures No relevant conflicts of interest to declare.

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