Infections during induction therapy of protocol CCLG-2008 in childhood acute lymphoblastic leukemia: a single-center experience with 256 cases in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Infections remain a major cause of therapy-associated morbidity and mortality in children with acute lymphoblastic leukemia (ALL).</p><p><b>METHODS</b>We retrospectively analyzed the medical charts of 256 children treated for ALL under the CCLG-2008 protocol in Beijing Children's Hospital.</p><p><b>RESULTS</b>There were 65 infectious complications in 50 patients during vincristine, daunorubicin, L-asparaginase and dexamethasone induction therapy, including microbiologically documented infections (n = 12; 18.5%), clinically documented infections (n = 23; 35.3%) and fever of unknown origin (n = 30; 46.2%). Neutropenia was present in 83.1% of the infectious episodes. In all, most infections occurred around the 15 th day of induction treatment (n = 28), and no patients died of infection-associated complications.</p><p><b>CONCLUSIONS</b>The infections in this study was independent of treatment response, minimal residual diseases at the end of induction therapy, gender, immunophenotype, infection at first visit, risk stratification at diagnosis, unfavorable karyotypes at diagnosis and morphologic type. The infection rate of CCLG-2008 induction therapy is low, and the outcome of patients is favorable.</p>

Research Progress on Expression Regulation, Function and Clinical Significance of CASP8AP2 Gene / 中国实验血液学杂志

We systematically reviewed the results of the studies on expression regulation, biological functions, and clinical prognostic significance of CASP8AP2 gene. At present, the studies showed that the expression of CASP8AP2 gene was regulated by Homeobox proteins and DNA methylation, and could be silenced by miRNA-210. This protein was involved in apoptosis mediated by FAS and TNFα, NF-κB activation mediated by TNFα, regulation of gene expression induced by glucocorticoid and mineralocorticoid receptor, comprising Cajal body and histone locus body, transcription of replication-dependent histone, 3' end processing of histone, regulation of S phase progression, in addition to functioning as coactivator of transcription factors c-Myb and p73 to activating many genes' expression. On the other hand, low expression of CASP8AP2 gene was associated with relapse in childhood ALL. The deletion of this gene was related to the poor prognosis of children with T-ALL and T lymphoblastic lymphoma. Furthermore, 3 SNPs in this gene were possibly correlated with genesis of diffuse large B cell lymphoma and childhood leukemia. In conclusions, CASP8AP2 was a multifunctional protein. It could function to regulate cell proliferation, apoptosis, and gene expression. In childhood hematological malignancies, CASP8AP2 was a promising molecular marker with prognostic significance. Some SNPs were possibly correlated with leukemo- and lymphomogenesis.

Clinical significance of CASP8AP2 gene methylation in childhood acute lymphoblastic leukemia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To study the methylation level in the promoter of caspase 8 associated protein 2 (CASP8AP2) gene between samples at diagnosis and in complete remission, and to investigate its relationship with clinical features and prognosis in children with acute lymphoblastic leukemia (ALL).</p><p><b>METHODS</b>Diagnostic DNA samples from 109 newly diagnosed children with ALL admitted from August 2007 to March 2010, and 94 ALL children in CR (complete remission) among them were collected. Bisulfite modification and MethyLight method established by our research team were used to determine the methylation level of the two key CpG sites (at -1189 and -1176) of the promoter of CASP8AP2 gene.</p><p><b>RESULTS</b>The average methylation level of the two CpG sites in newly diagnosted samples was higher than that in CR samples (71.1% ± 1.7% vs 64.2% ± 21.2%) (P = 0.008). Analysis with receiver operating characteristic (ROC) curve showed that the area under curve was 0.687 (P = 0.024), indicating that the methylation level of the two CpG sites was able to predict relapse efficiently to some extent, 76.9% was chosed as a cutoff value to divide the patients into high methylation group (49 patients) and low methylation group (60 patients). The incidence of relapse in high methylation group was higher than that in low methylation group (20.4% vs 6.7%) (P = 0.044), five year relapse free survival in high methylation group was also lower than that in low methylation group (Log rank, P = 0.033). Furthermore, high methylation at new diagnosis were correlated with high level of minimal residual disease (MRD) before consolidation therapy (P = 0.011). In the 34 children with MRD ≥ 10(-4) at the end of induction remission, the relapse rate of high methylation patients was significantly higher than that of low methylation patients (8/16 vs 3/18)(P = 0.038).</p><p><b>CONCLUSION</b>The abnormal hypermethylation of the two CpG sites (at -1189 and -1176) of the promoter of the CASP8AP2 gene is possibly associated with leukemogenesis in childhood ALL. The treatment outcome is more poor in patients with hypermethylation than that in patients with low methylation. The combination of the methylation level of the two CpG sites and MRD level at the end induction remission is able to predict relapse more effectively.</p>

Correlation analysis of FPGS rs10760502G>a polymorphism with prognosis and MTX-related toxicity in pediatric B-cell acute lymphoblastic leukemia / 中国实验血液学杂志

This study was aimed to explore the relation between folylpolyglutamate synthetase (FPGS) rs10760502 polymorphism and prognosis and methotrexate (MTX)-related toxicities in pediatric B-cell acute lymphoblastic leukemia (B-ALL). Sequenom MassARRAY was used to genotype rs10760502. The χ(2) test, Kaplan-Meier method and Cox regression models were used to analyze the data. The results indicated that A allele carriers (GA+AA) had poor relapse free survival (RFS, log-rank: P = 0.004) and event free survival (EFS, log-rank: P = 0.022) compared with the GG genotype carriers. Multivariate Cox-regression analysis results showed that A allele is an independent prognosis factor for poor RFS [hazard ratio (HR), 20.173; 95% CI, 2.535-160.545; P = 0.005] and EFS (HR, 8.133; 95% CI, 1.718-38.512; P = 0.008). No relationship was found between any MTX toxicity and rs10760502 polymorphism. It is concluded that FPGS rs10760502G>A polymorphism may affect the treatment outcome of B-ALL patients.

Evaluation of early response to treatment and its prognostic value in childhood acute lymphoblastic leukemia / 中国实验血液学杂志

This study was purposed to investigate the prognostic value of early response to treatment in childhood acute lymphoblastic leukemia (ALL). Four indexes were used to assess early response to treatment including response to prednisone on day 8 (D8-PR), percentage of lymphoblast in bone marrow on day 22 (D22-BM) and day 33 (D33-BM), the level of minimal residual disease (MRD) on day 33 (D33-MRD) by morphological and molecular biological method in 426 children with ALL. Prognostic impact of early response to treatment was analyzed, and multivariate analysis of the predictive value was performed by Cox-regression analysis. All patients were followed up until October 31, 2013, with a median follow-up time of 80 months (0.5 to 106 months). The results showed that there were significant differences between event free survivals (EFS) of the sub-groups divided according to the four indexes. The 8 years-EFS in patients with prednisone good response (PGR) was significantly higher than that in patients with prednisone poor response (PPR);patients with M1 in bone marrow on day 22 or day 33 had the better outcomes than that of patients with M2/M3;patients with high level of MRD ( ≥ 10(-4)) had the worse outcomes as compared with patients with low level of MRD (<10(-4)) (P < 0.001). Cox proportional hazard model analysis showed that BCR/ABL fusion gene positive, D8-PR, D33-BM and D33-MRD were the independent prognostic factors for childhood ALL, and the hazard ratio of D33-MRD ≥ 10(-2) was highest (HR:11.886, P < 0.001). It is concluded that early response to treatment is an independent prognostic factor with important prognostic values, and it has important clinical guiding instructive significance for risk stratification in the treatment of children ALL.

Evaluation of the efficacy of two successive protocols on pediatric acute lymphoblastic leukemia with E2A-PBX1 fusion gene / 中华儿科杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy of BCH-03 and CCLG-08 protocols in treating E2A-PBX1 pediatric acute lymphoblastic leukemia (ALL).</p><p><b>METHOD</b>From January 2003 to January 2011, 59 ALL patients identified as E2A-PBX1 were analyzed in a retrospective study. There were 37 and 22 patients treated with Protocol BCH-03 and CCLG-08, respectively. The clinical characteristics at diagnosis, response to early treatment, the time of relapse, relapse-free survival (RFS) and event-free survival (EFS) in the two groups were analyzed.</p><p><b>RESULT</b>There were no significant differences in gender, age, initial white blood cell count, the central nervous system involvement, immunophenotype, prednisone response, the rate of complete remission, and the time of relapse between the two groups (P > 0.05). The only difference in induction therapy of the two protocols existed in the glucocorticoids used, that is, BCH-03 used 60 mg/m(2) prednisolone and CCLG-08 used 6 mg/m(2) dexamethasone. The doses of vincristine, daunorubicin and L-asparaginase were the same in the two groups. At the end of induction therapy, the MRD negativity rate in BCH-03 group was significantly higher than that in CCLG-08 group (84.2% vs. 47.1%, P = 0.018). The incidences of severe infection of the two groups during induction of remission were similar (P = 0.135). The EFS of BCH-03 group was significantly superior to that of CCLG-08 group (94.5% vs. 71.5%, P = 0.010), and the RFS of BCH-03 group tended to be better than that of CCLG-08 group (94.5% vs. 78.6%, P = 0.059).</p><p><b>CONCLUSION</b>Compared to Protocol CCLG-08, Protocol BCH-03 was more effective for pediatric E2A-PBX1 ALL, and 60 mg/m(2) prednisolone was more suitable for the induction therapy of this subtype of pediatric ALL.</p>

Treatment with combined all-trans retinoic acid and anthracycline of 37 children with acute promyelocytic leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>To study the clinical features of childhood acute promyelocytic leukemia (APL) and to analyze the survival and prognostic factors and efficacy and safety of combined treatment with all-trans retinoic acid (ATRA) and anthracycline.</p><p><b>METHOD</b>The clinical features of 37 children with newly diagnosed APL hospitalized in our center during January 2005 to February 2009 were retrospectively analyzed.</p><p><b>RESULT</b>Thirty percent of patients were at low risk, 43% patients were at intermediate risk, 27% patients were at high risk. Sixty percent of patients had DIC. Retinoic acid syndrome (RAS) was present in 2 patients (6%). Death during induction occurred in 3 patients (8%). Complete remission (CR) was achieved in 83.7% of patients. The patients in high risk group had higher risk than those in intermediate and low risk group (P = 0.029). The time to achieve CR was not significantly different (P = 0.612). Idarubicin had no advantage compared with daunorubicin in time to achieve CR (P = 0.628). Survival rates were calculated using Kaplan-Meier statistical method, and 2 years event-free survival (EFS) rate was 81%, the 2-year EFS rate was 100% for low-risk group, 81% for intermediate-risk group, and 60% for high-risk group.</p><p><b>CONCLUSION</b>Using combined chemotherapy with ATRA and anthracyclines had the following advantages: high CR rate, high long-time survival rate and low side effect. DIC remained the main complication among patients receiving induction treatment. Initial WBC count and platelet count are important prognostic factors which might be useful in prognostication and treatment planning.</p>

Allogeneic stem cell transplantation for 8 patients with malignant infantile osteopetrosis in China / 中华儿科杂志

<p><b>OBJECTIVE</b>Osteopetrosis is a rare genetic disorder and the malignant infantile osteopetrosis (MIOP) is the worst subtype of this disease. Seventy percent of patients die in six years of life without proper treatment. Hematopoietic stem cell transplantation (HSCT) offers the only chance of cure for MIOP.</p><p><b>METHOD</b>Retrospective analysis was performed on 8 patients with MIOP who underwent HSCT in Beijing Children's Hospital during the period from 2006 to 2011.</p><p><b>RESULT</b>Eight cases (4 male and 4 female, mean age at HSCT 13.5 months) were diagnosed as malignant infantile osteopetrosis. Conditioning regimen included fludarabine, busulfan and cyclophosphamide. All patients received cyclosporin for prophylaxis of graft vs. host disease (GvHD). A UMD recipient underwent CD34(+) cell selection. ATG/ALG, mycophenolate mofetil (MMF) and methotrexate (MTX) used for recipients with unrelated cord donor (2) and recipients with haplo-identical donors (5). Average time for neutrophil engraftment was 15.7 day (9 - 36), platelet engraftment was 43.3 day (10 - 68). The patients were followed up from 47 days to 5 years, 1 patient died of post-transplant complications. Seven cases presented better in clinical manifestation. Acute GvHD I°-II° was observed in 6 patients, III°-IV° in 2 patients. It was controlled by anti-GvHD therapy.</p><p><b>CONCLUSION</b>Non-allogenic stem cell transplantation treatment of infantile MIOP showed high survival rate and restoration of hematopoiesis in haploid transplant patients, therefore, non-allogenic HSCT may be an option to treat MIOP in children.</p>

Clinical research on clearance of leukemic cell during induction of remission therapy in children with precursor B cell acute lymphoblastic leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the clinical value of clearance of leukemic cell during induction of remission therapy in children with precursor B cell acute lymphoblastic leukemia (BCP-ALL), and to assess the applicative value of different indexes.</p><p><b>METHOD</b>From April 2005 to April 2008, 206 children with de novo BCP-ALL were admitted. We firstly analyzed the effect of clearance of leukemic cells during induction of remission therapy on relapse-free survival (RFS). Four indexes were used to assess the clearance of leukemic cells including prednisone response on day 8 (d8-PR), percentage of lymphoblast in bone marrow on day 22 (d22-BM) and day 33 (d33-BM), and bone marrow (BM) minimal residual disease (MRD) detection on day 33 (d33-MRD). Then the sensitivity, specificity, positive predictive value and negative predictive value of the four indexes to assess their ability to predict relapse were analyzed. Finally, the consistency between two of the four indexes to explore the relationships among them were analyzed.</p><p><b>RESULT</b>There were significant differences between RFS of the sub-groups divided according to d8-PR, d22-BM, d33-BM, d33-MRD (P < 0.01); Cox proportional hazard model analysis showed that d33-MRD ≥ 10(-3) and positive BCR/ABL fusion gene were the independent prognostic factors. Sensitivity of d33-MRD was higher than that of morphology detection (d22-BM, d33-BM and d8-PR) in prediction of relapse, and positive predictive value of morphology detection was higher than that of d33-MRD. Sensitivity could be greatly increased by combination with clinical and biological characteristics. Consistency could not be found between d8-PR and d22-BM, d33-BM, d33-MRD, as well as between d22-BM, d33-BM, and d33-MRD. However, all cases of d22-BM, d33-BM M2/M3 were d33-MRD ≥ 10(-3), while the same phenomenon could not be found for patients with poor d8-PR.</p><p><b>CONCLUSION</b>Clearance of leukemic cell during induction of remission therapy in children with BCP-ALL had important clinical value. Sensitivity of MRD detection after induction of remission therapy was higher than that of morphological analysis to predict relapse. Morphological analysis could only identify a few patients with very high risk of relapse and the sensitivity could be increased by combination with clinical biological characteristics. The simple prednisone response may contain some prognostic information that could not be covered by analysis of BM cells. It may be the best way to assess the clearance of leukemic cells to combine the prednisone response with MRD detection after induction of remission therapy.</p>

Gene rearrangement pattern of immunoglobulin and T-cell receptor (Ig/TR) and its clinical characteristics in children with SET-NUP214 fusion gene-positive leukemia/lymphoma / 中国实验血液学杂志

The purpose of this study was to analyze the gene rearrangement pattern of immunoglobulin and T-cell receptor (Ig/TR) and its clinical characteristics in three children with SET-NUP214 fusion gene positive leukemia/lymphoma. The transcript of SET-NUP214 fusion gene was detected by RT-nested PCR. The pattern of Ig/TR gene rearrangement was analyzed by using the BIOMED-2 multiplex PCR assays. Allelic-specific primers were designed for further monitoring the minimal residual disease (MRD). The results indicated that the fusion site located between exon 7 of SET and exon 18 of NUP214 at mRNA level in the three patients. The diagnoses were made as the mixed phenotype of acute leukemia (MPAL) for patients 1, acute T-lymphoblastic leukemia (T-ALL) for patients 2, and stage IV T-lymphoblastic lymphoma (T-LBL) for patients 3, respectively. Patient 1 responded to chemotherapy very poorly and relapsed at month 6 after hematopoietic stem cell transplantation. Patient 2 had high MRD (> 10(-2)) at the end of inducing remission therapy (day 33) which implied poor outcome, and died of toxic epidermal necrolysis and sequent serious infection. Patient 3 achieved hematological complete remission (CR) and MRD negative at day 15 and day 33 respectively. The duration of CR lasted for 30 months. Clonal TR gene rearrangements were detected in all the three patients. The rearrangements of TRD, TRG and TRB were found in patient 1 and 3. The rearrangements of TRD, TRB, IgH and IgK Kde were detected in patient 2. All the 6 TRB rearrangements detected were incomplete rearrangements, whereas 85.7% and 14.3% of the TRD, and TRG rearrangements were complete and incomplete, respectively. It is concluded that the transformation of SET-NUP214(+) leukemia/lymphoma cells may occur after the rearrangements of TRD and TRG and shortly after TRB rearrangement. The leukemia/lymphoma cells of patient 1 and 2 are more immature which may be related with poor outcome or response to chemotherapy.

Effect of RBC lysing solution on CD34(+) cell counting / 中国实验血液学杂志

To investigate whether the RBC lysing solution can affect the results of relative enumeration of CD34(+) cells, 37 mobile peripheral blood apheresis products were stained using CD34-PE and CD45-FITC monoclone antibodies and RBCs were then lysed by two lysing solution commercially available (one named FACS Lysing Solution, FACS; another IOTest 3 Lysing Solution, IOTest) and one lysing solution self-prepared. After being processed by lyse-and-then-washed method, samples were detected by FACSC anto flow cytometer. The percentages of CD34(+) cells were determined based on ISHAGE gating strategy, forward and side scatter (FSC and SSC) characteristics, percentage of CD45(+) cells were recorded simultaneously. The results showed that by lyse-and-then-wash method, the percentages of CD34(+) cells in FACS-treated samples were significantly lower compared with that in IOTest-treated samples (0.50 +/- 0.42 vs 0.92 +/- 0.59, p = 0.004), but no statistical difference was observed between IOTest-treated and ourselves-prepared-treated samples. The intensities of FSC and SSC in cells of IOTest-treated sample were significantly higher compared with that in cells of FACS-treated sample (p < 0.01). The proportion of CD45(+) cells in IOTest-treated samples was lower than that in FACS-treated samples. The WBC count of samples was not correlated to the amount of CD34(+) cells (r(s) = 0.192, p = 0.357). It is concluded that the red cell lysing solution shows unexpected effect on detecting and counting CD34(+) cells, prudence should be taken to select such reagents at FCM performance.

Tolerability of 6-mercaptopurine in children with acute lymphoblastic leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>6-Mercaptopurine (6-MP) has been the backbone of maintenance chemotherapy for acute lymphoblastic leukemia (ALL), the response to 6-MP is highly variable, adverse events leading to discontinuation or dose-reduction (children intolerant) of 6-MP occur in many children with ALL. The aim of this study was to investigate the tolerability of 6-MP and to optimize thiopurine use.</p><p><b>METHODS</b>The authors evaluated in a prospective manner the tolerance of 6-MP in ALL children from Oct. 1, 2004 to Sept. 30, 2007 who were newly diagnosed in Beijing Children's Hospital, using BCH-ALL-2003 protocols, during the maintenance therapy and followed up to Sept. 30, 2008. All children had a treatment period of at least 3 months for maintenance therapy.</p><p><b>RESULTS</b>Totally 133 children including 81 boys and 52 girls at median age of 67 months (18 - 188 months), 100% of the patients went into complete remission (CR) on day 33 of induction chemotherapy, and the median time to CR was 26 months (6 - 47 months). All the children had maintenance therapy from 3 to 25 months (mean 13.5 +/- 7.4) and 72(54%) received 6-MP standard doses continuously for total courses, the median daily dose of 6-MP was 46 mg/(m(2).d) 6-MP, their WBC was (3 - 4) x 10(9)/L, ANC (1.5 - 2) x 10(9)/L, they had no severe liver toxicity. In 4 children the dose of 6-MP was increased to 125% because WBC was higher than 6 x 10(9)/L, ANC higher than 3 x 10(9)/L. Sixty one children (46%) had poor tolerability to 6-MP, they experienced adverse events that led to discontinuation (n = 19) or dose reduction (n = 42) of 6-MP, the actual mean dose for the 42 cases was 25 - 30 mg/(m(2).d) and the time to occurrence of toxic effects was 2.5 weeks. Reasons for discontinuation or dose reduction were severe myelotoxicity occurred in 48 children, hepatotoxicity in 12, and skin rash in one.</p><p><b>CONCLUSIONS</b>In this cohort of ALL children, the difference of tolerance to oral 6-MP was obvious, 54% of the children well tolerated 6-MP during the whole course at oral standard dose, and severe granulocytopenia did not occur. However, 46% developed severe granulopenia or hepatotoxicity, the dosage had to be reduced in order to decrease the probability of severe toxicity. It is suggested that standard dose of 6-MP is not always the maximum tolerant dose in some children and inadequate dose may be the cause of therapy failure.</p>

Characteristics of fusion gene and immunophenotype in MLL gene rearrangement positive childhood acute lymphoblastic leukemia / 中国实验血液学杂志

The study was aimed to investigate the fusion gene transcript and immunophenotypic characteristics of the mixed linage leukemia (MLL)-rearranged positive childhood acute lymphoblastic leukemia (ALL). The incidence of MLL rearrangement in 601 cases of ALL patients was detected by the multiple-nested polymerase chain reaction (PCR); the subtypes and features of the fusion gene transcript were analyzed by PCR products sequencing; the immunophenotypic characteristics at diagnosis were compared between the 22 MLL rearrangement positive of ALL patient, 30 negative control which selected randomly from the patients whose fusion gene could not be detected in the same term and 43 pro-B-ALL patients. The results showed that the incidence of MLL positive ALL was 3.66%, constituted 29.9% of the pro-B-ALL. The MLL rearrangement positive 20 B-ALL patients were all CD10 negative; the number of patients who carried CD13, CD33 and CD34 was lower than that of pro-B-ALL who had no fusion gene, whereas the expression of CD20, CD22, CD2, CD5, CD7 showed no difference. 4 kind partner genes of MLL-AF4, AF9, AF10 and ENL were detected. The fusion loci of MLL gene were mainly located at the exon 6, 7, 8 and many kind of fusion loci of MLL may exist in one patient; whereas its partner gene fusion loci were relatively single. A transcript contains a random insert sequence existed in a transcript of one MLL-AF10+ patient. It is concluded that though incidence of MLL rearrangement is low, but it has a variety of fusion transcripts, the ALL patients has unique biological characteristics at immunophenotype and fusion transcript.

Correlation of E2a-pbx1 expression level with clinical characteristics and early response to treatment in children with acute lymphoblastic leukemia / 中国实验血液学杂志

This study purposed to investigate the correlation of expression level of e2a-pbx1 (immunoglobulin enhancer binding factor-Pre-B leukemia) with clinical characteristics and early response to treatment in children patients with acute lymphoblastic leukemia (ALL). The expression level of e2a-pbx1 at primary diagnosis in 45 children with ALL, and on day 33 after induction of remission in 23 children with ALL were detected by real-time quantitative polymerase chain reaction (RQ-PCR). The corelation of e2a-pbx1 expression level at primary diagnosis, MRD level with clinical characteristics and early response to treatment were all observed and explored. The expression level of e2a-pbx1 and clinical characteristics at primary diagnosis were compared between MRD negative and MRD positive patients. The results showed that the expression level of e2a-pbx1 was correlated with the blast percentage in peripheral blood at primary diagnosis. The MRD level at day 33 after induction of remission in 23 children were not related to the expression level of e2a-pbx1 at primary diagnosis and the clinical characteristics. The expression level of e2a-pbx1 at primary diagnosis in MRD positive patients was higher than that in MRD negative patients, while their age was significantly lower than that of patients with MRD negative. The blast percentage in peripheral blood at diagnosis of patients with presenting leukocyte count < 25 x 10(9)/L was significantly lower than that of patients with presenting leukocyte count >or= 25 x 10(9)/L, while the platelet count was higher. It is concluded that the expression level of e2a-pbx1 at primary diagnosis indicates the load of tumor in patients. In patients whose MRD were positive, the expression level of e2a-pbx1 at primary diagnosis is high and their age is young. The platelet count is low in the patients with high load of tumor at primary diagnosis.

Characteristics of T cell receptor beta gene rearrangements and its role in minimal residual disease detection in childhood T-cell acute lymphoblastic leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the characteristics of T cell receptor beta (TCRbeta) gene rearrangements in children with T-cell acute lymphoblastic leukemia (T-ALL) and establish a system of quantitative detection of MRD with real-time quantitative (RQ-PCR) targeted at TCRbeta gene rearrangement.</p><p><b>METHODS</b>Multiplex polymerase chain reaction (PCR) designed by BIOMED-2 was used to detect TCRbeta gene rearrangements in the bone marrow samples of 26 children with T-ALL. Sequence of junction region were then compared and analyzed in IMGT database. Allele specific oligonucleotide (ASO) upstream primers were designed complementary to the V-D-J or D-J junctional region of TCRbeta gene rearrangements. Samples at diagnosis were serially diluted in DNA obtained from mononuclear cells (MNC) from a pool of 20 healthy donors to generate the patient specific standard curves. Subsequently, a TCRbeta RQ-PCR assay to quantify MRD with germline Jbeta primer/probe combinations was applied in six patients. To check the quantity and quality of DNA, the investigators used RQ-PCR analysis for the N-ras gene.</p><p><b>RESULTS</b>Clonal rearrangements were identified in 92.3% childhood T-ALL (Vbeta-Dbeta-Jbeta rearrangements in 84.6%, Dbeta-Jbeta rearrangements in 50%). Comparative sequence analysis of 42 TCRbeta recombinations revealed two downstream Vbeta families (BV5, BV6) were preferentially used. The segment Jbeta2.7 in childhood T-ALL was preferentially used. Jbeta1.3, Jbeta2.4, and Jbeta2.6 were not found to be used. The slope of the standard curves was from -3.54 to -3.37 and the intercepts were from 19.35 to 20.51. The correlation coefficients of all 6 standard curves were excellent (> or = 0.98). All the RQ-PCR quantitative range reached 10(-4). MRD analysis of follow up samples showed that MRD increased before relapse.</p><p><b>CONCLUSION</b>RQ-PCR analysis of TCRbeta gene rearrangements was highly sensitive and specific, it will be of high value for future T-ALL MRD studies. And quantitative and serial study of MRD may be of prognostic importance.</p>

Relation between TEL-AML1 expression level and clinical characteristics as well as early response to treatment in children with acute lymphoblastic leukemia / 中国实验血液学杂志

The study was aimed to investigate the relation between the expression level of TEL-AML1 (translocation ETS leukemia-acute myeloid leukemia 1) fusion gene and clinical characteristics as well as early response to treatment in children with ALL (acute lymphoblastic leukemia). With real-time quantitative polymerase chain reaction (RQ-PCR), the expression level of TEL-AML1 at diagnosis and MRD (minimal residual disease) at the end of induction of remission were detected in 35 children with ALL, including 20 SR (standard risk) and 15 IR (intermediate risk) patients. The expression level of TEL-AML1 and clinical characteristics at diagnosis were compared between MRD negative and MRD positive patients. The relation between TEL-AML1 expression levels at diagnosis, MRD level and clinical characteristics as well as early response to treatment were also explored. The results indicated that the expression levels of TEL-AML1 at diagnosis were 1.63 x 10(4) copies/10(4) copies ABL (median). At the end of induction of remission, 16 patients (10 SR and 6 IR patients) did not achieve molecular remission, whose MRD levels were 0.84 - 282.93 copies/10(4) copies ABL. No relation was found between expression levels of TEL-AML1 at diagnosis and clinical characteristics as well as MRD level. There was a significant relation between MRD level and blast count in peripheral blood (PB) at day 8 after prednisone trial induction. Significant relations between MRD level and presenting leukocyte count, blast percentage in PB were also found in the patients with presenting leukocyte count < 25 x 10(9)/L. TEL-AML1 expression level at diagnosis of MRD negative patients was lower than that of MRD positive ones. It is concluded that therapy after induction of remission is of importance by the fact that 45.71% children with TEL-AML1(+) ALL did not achieve molecular remission at the end of induction of remission. The effectiveness of prednisone trial predicts the MRD level. In addition, presenting leukocyte count, blast percentage in PB and TEL-AML1 expression level at diagnosis may have an effect on MRD level to some extent.

Variant fusion transcript in ALL children with E2A-PBX1 fusion gene positive / 中国实验血液学杂志

The study was aimed to investigate the expression of E2A-PBX1 fusion gene in children with acute lymphoblastic leukemia (ALL). The primers located at different sites of E2A and PBX1 gene were used to screen for the fusion gene in 410 children with ALL, including 362 cases of B cell ALL and 48 cases of T cell ALL. The results showed that 17 children carried the fusion gene. The positive rate was 4.1%. Furthermore, all the positive cases expressed a variant type of fusion transcript. It resulted from different splicing of the 13th exon (159 bp) of E2A gene. Analyses with BLASTn indicated that the variant type of transcript retained the open reading frame. However, the loss of 53 amino acid residues which were located at the 2nd activation domain resulted in the partial deletion of the putative loop-helix (LH) structure as well as the complete deletion of the heptad leucine repeat. It is concluded that all the children with ALL positive for the E2A-PBX1 fusion gene express typical and variant fusion transcripts. The latter resulted from different splicing of the 13th exon (159 bp) of E2A gene. The loss of 53aa would lead to the partial deletion of the putative loop-helix (LH) structure as well as the complete deletion of the heptad leucine repeat.

Immunophenotypic characteristics of children with acute lymphoblastic leukemia carrying TEL-AML1 fusion gene / 中国实验血液学杂志

To investigate the immunological and other clinical characteristics in TEL/AML1+ childhood B-acute lymphoblastic leukemia (B-ALL), immunophenotyping was performed with three-color flow cytometry, and the expression of TEL-AML1 fusion gene was detected with nested RT-PCR. Diagnosis was made according to FAB and MIC criteria. The results showed that (1) among 119 children with B-ALL, 22 (18.5%) were TEL-AML1 positive and classified as L2 morphological subtype. In TEL-AML1+ group, positive rate and score of PAS, which were 65% and 121 respectively, were all higher than that of TEL-AML1- group (P < 0.05); (2) compared with TEL-AML1- group, no significant difference was found in age, gender, white cell count and blasts count in peripheral blood of TEL-AML1+; (3) in TEL-AML1+ group, 21 out of 22 (95.5%) were common ALL, as compared with TEL-AML1- group, the positive rate of CD13 was higher (59.1%, 13/22) and the positive rate of CD20 was lower (22.7%, 5/22) than that in TEL-AML1- group, respectively (P < 0.05), and the mean fluorescence index of CD10 and HLA-DR significantly increased to 92.80 and 53.61, respectively (P < 0.05). It is concluded that TEL-AML1 rearrangement is a frequent molecular abnormality in childhood ALL. Leukemic blasts with this anomaly have special immunophenotypic characteristics. These characteristics may be useful in detection of minimal residual leukemia.

Relationships between thiopurine methyltransferase gene polymorphisms and its enzymatic activity / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the thiopurine methytransferase (TPMT) gene polymorphisms and its enzymatic activity, and to clarify the significance of TPMT activity and gene polymorphisms on individualized therapy with thiopurines.</p><p><b>METHODS</b>The TPMT activity and gene polymorphisms were determined in an unrelated population of 250 Chinese healthy blood donors, 100 cords blood and 280 patients with acute leukemia. The TPMT genotyping assay was based on polymerase chain reaction (PCR), restriction digestion of PCR products, denaturing high-performance liquid chromatography (DHPLC) and SNaPshot sequencing and direct DNA sequencing in the TPMT exon 5 (G238C), TPMT exon7 (G460A) and TPMTexon10 (A719G). Erythrocyte TPMT activity was measured by high-performance liquid chromatography (HPLC).</p><p><b>RESULTS</b>The frequency of TPMT polymorphism in 250 Chinese healthy blood donors, 100 cords blood and 280 patients with acute leukemia was low (3.5%), and all the varied alleles were TPMT* 3C (exon 10A719G). All of them were TPMT* 1/TPMT* 3C heterozygote. The TPMT activity was between 6 and 12 U. The activity in 95.1% was more than 12 U (13 - 32 U), while the activity in others (4.9%) was 6 - 12 U. TPMT activity and genotype were concordant. Of 630 subjects evaluated, TPMT activity of heterozygous individuals in Chinese healthy blood donors, cords blood and acute leukemia patients were 9.1 U, 9.3 U and 9.07 U, respectively, significantly lower than that in general population (17.6 U, 17.67 U and 18.6 U, respectively). In the samples analyzed, ten subjects with heterozygous phenotypes (6/15 acute leukemia children and 4/16 healthy blood donors and cords blood) did not have TPMT* 2, TPMT* 3A or TPMT* 3C. Therefore, other factors may affect on TPMT activity.</p><p><b>CONCLUSION</b>TPMT gene polymorphisms and its activity were concordant. The heterozygotes had low TPMT activity. Therefore, detection of TPMT genotype and its activity is useful. These findings hold a promise of improving the safety and efficacy of thiopurines therapy.</p>

Analysis of T cell repertoire in children with acute B lymphoblastic leukemia / 中华儿科杂志

<p><b>OBJECTIVE</b>The complementarity determining region 3 (CDR3) of T cell receptor (TCR) is the place through which T cells connect to the antigen. The lengths and DNA sequences of CDR3s are different according to different T cell clones. This leads to a diverse TCR CDR3 repertoires which can reflects the functional status of T cells precisely. This study aimed at elucidating the abnormality of TCR beta chain variable region (BV) CDR3 repertoires of children with acute B lymphoblastic leukemia, the pathogenesis of leukemia associated with T cell dysfunction and the immuno-reconstruction of T cells after the chemotherapy.</p><p><b>METHODS</b>Twelve children aged from 3 to 13 years (average 4.50 +/- 3.78 years) with acute B lymphoblastic leukemia before chemotherapy and 8 healthy control donors aged from 6 to 16 years (average 10.30 +/- 3.00 years) were enrolled. Four of 12 patients were studied for the second time 3 months after complete remission (CR). Reverse transcription-polymerase chain reaction (RT-PCR) and polyacrylamide sequencing gel electrophoresis were used to detect the diversity of TCR BV CDR3 repertoires of these children.</p><p><b>RESULTS</b>(1) The expression of BV2 and BV3 in 12 children increased and BV17 and BV18 decreased before the chemotherapy as compared with controls (P < 0.05). There were 4 children with a lower level expression of BV21 before the chemotherapy, and much lower level expression was found after the remission. (2) Normally each lane contained eight to ten bands, which represented unique CDR3 sizes for a given TCR BV family. Bands differed in size by 3 nucleotides and generally form a Gaussian distribution. There were 14% TCR BV families with abnormal CDR3 length distribution in 12 patients before therapy, which was significantly higher than that of controls (5.5%, P < 0.05). Restricted CDR3 length distribution was observed in BV14, BV1, BV16, BV20, BV13.1, BV13.2 and BV6. Every abnormal BV family recovered to normal Gaussian distribution 3 months after CR.</p><p><b>CONCLUSION</b>T lymphocytes in children with acute B lymphoblastic leukemia revealed markedly skewed repertoires, which suggests the abnormality of T cell functions. Most abnormal T cell repertoires recovered to normal Gaussian distribution 3 months after the first CR, which suggests the immunological reconstitution of T cell repertoires.</p>