[Clinical and experimental studies of childhood acute myeloid leukemia with 11q23/MLL rearrangements].

OBJECTIVE: To explore clinical and experimental features of 28 cases of childhood acute myeloid leukemia (AML) with 11q23/MLL gene rearrangements. METHODS: Karyotypes of 234 cases of de novo childhood AML were analyzed using short-term culture of bone marrow cells and R-banding. The fusion transcripts involving MLL gene and partial tandem duplication of MLL (MLL-PTD) were detected by multiple reverse transcription polymerase chain reaction (RT-PCR) assay. Two cases with 11q23 translocation by karyotypic analysis but with negative result of multiple RT-PCR were studied with MLL-dual-color fluorescence in situ hybridization (D-FISH). RESULTS: R-banding karyotypic analysis has revealed 20 cases with 11q23 translocation (14 cases with M5, 4 cases with M4, 2 cases with M2), including 12 cases with t(9;11)(p22;q23), 3 cases with t(1;11)(q21;q23), 2 cases with t(6;11)(q27;q23), 1 case with t(11;19)(q23;p13), 1 with t(5;11)(q31;q23), and 1 with t(X;11)(q24;q23). Eighteen cases with 11q23 translocation having fusion transcripts involving MLL genes were confirmed with multiple RT-PCR; 2 cases showed negative results, but they were confirmed to have MLL rearrangements by D-FISH. MLL-PTD was also detected in 8 cases (4 cases M5, 2 cases M4, M2 and M6, one case each) from the other childhood AML cases. The total incidence of 11q23/MLL gene rearrangements was 11.97% (28/234), and most of patients(85.7%, 24/28) were M4/M5. The complete remission (CR) rate after treatment for the 28 cases with MLL rearrangements was 53.8%, the difference was significant by statistics (P< 0.05) compared with 90.5% for the control group (M4/M5 childhood AML with other karyotypic abnormalities or normal karyotype). Of them, 2 cases receiving intensive chemotherapy survived for 81 and 66 months, respectively, 4 cases receiving allogeneic stem cell transplantation survived for 21, 20, 16 and 11 months, respectively, and are still alive with CR. The medium survival (MS) time for 28 cases with 11q23/MLL rearrangements was 11 months, whereas the MS for control group was 15 months. The difference was not statistically significant(P> 0.05). CONCLUSION: The 11q23/MLL rearrangements is highly correlated with the occurrence of monocytic leukemia (M4 and M5). The 11q23 translocation and MLL-PTD are mutually exclusive, though both are indicative of poor prognosis. Intensive chemotherapy and allogeneic stem cell transplantation may ameliorate the clinical outcome. Multiple RT-PCR combined with karyotypic analysis and D-FISH are useful for screening the 11q23/MLL rearrangements in childhood AML.

[Clinical and laboratory features of pediatric acute myeloid leukemia with inversion of chromosome 16].

OBJECTIVE: To evaluate the clinical and laboratory features of pediatric inv(16) acute myeloid leukemia (AML) retrospectively. METHOD: Dual color fluorescence in situ hybridization (D-FISH) using a LSI CBFß inv(16) break apart probe labeled by Spectrum red and Spectrum green was performed in 15 acute myeloid leukemia cases, including 13 cases with or without abnormal eosinophils but with positive core binding factor ß (CBFß)-MYH11 fusion transcript detected by RT-PCR, and 2 cases with trisomy 8 (+8). The results were compared with the morphology, immunophenotype, karyotype and RT-PCR. RESULT: Morphologically, 12 cases were diagnosed as M(4)EO, 2 as M(4), and 1 as M(2a). Immunophenotypically, all 13 AML cases with inv(16) showed positive expression of CD(13) and CD(33), but without the expression of any lymphoid lineage antigens. Karyotyping analysis with G-banding detected inv(16) in 10 AML cases, including 9 M(4)EO cases and 1 M(2a), but only 5 positive cases were detected using R-banding technique. Among them, 2 cases had simultaneous +8 and trisomy22 (+22), one had +22 only in addition to inv(16). D-FISH revealed a CBFß-MYH11 rearrangement in 13 cases of AML with positive RT-PCR results, and the mean positive rate of cell detection was 55.15% (range 37.0% - 86.0%). The complete remission rate (CR) and median survival period in this series of inv(16) AML were 81.5%and 11 months, respectively, of whom, 8 cases were still in CR. Relapse and karyotypic evolution were seen in case 5 with +8, +22 in addition to inv(16). CONCLUSION: AML with inv(16) is a special subtype. Most cases belong to M(4)EO. Its prognosis is good in general, but it seems to be an unfavorable feature for AML with inv(16) and +8, +22 simultaneously, especially with karyotypic evolution. For detection of inv(16), G-banding technique is evidently superior to R-banding technique. D-FISH combined with RT-PCR are more sensitive and reliable than chromosome banding analysis.

[Classical and molecular cytogenetic abnormalities in 124 pediatric patients with acute lymphoblastic leukemia].

OBJECTIVE: In childhood acute lymphoblastic leukemia (ALL), cytogenetics plays an important role in diagnosis, allocation of treatment and prognosis. On the basis of the conventional cytogenetic analysis, molecular methods have improved pediatric hematologists/oncologist's ability to accurately and rapidly perform risk-stratification on patients with childhood ALL during the last few years. The aim of the present study was to assess the demography of cytogenetic abnormalities in childhood ALL. METHOD: The study subjects consisted of 124 newly diagnosed ALL patients younger than 16 years of age, who were diagnosed at the Department of Pediatric Hematology/Oncology, Soochow University Children's Hospital. The diagnosis and FAB subtypes of ALL was determined by Wright-Giemsa-stained bone marrow smears and cytochemical staining. Immunophenotyping of the bone marrow samples was performed by flow cytometry. Multiplex polymerase chain reaction (Multiplex PCR) analysis was performed to detect the 29 most common leukemia translocations for routine molecular diagnostic hematopathology practice, and complement the information gained from conventional cytogenetic analysis. RESULTS: Cytogenetic analysis was successful in 112 of 124 children with ALL. Sixty-eight (60%) of them had clonal chromosomal abnormalities. Numerical imbalances consisted of hyperdiploid (> 47 chromosomes, 36 cases), hypodiploid (< 46 chromosomes, 14 cases), pseudodiploidy (18 cases). Chromosomal translocations were observed in 13 patients by conventional cytogenetic analysis. Three cases were found positive for 4; 11 translocation, 3 cases for 9; 22 translocation, 1 case for 1; 19 translocation and 6 cases for other rare translocations. Multiplex-PCR analysis detected 116 of the 124 ALL patients. Thirteen cases of TEL-AML1, 10 cases of rearrangement in the MLL gene, 4 cases of E2A-PBX1, 4 cases of E2A-HLF, 3 cases of BCR-ABL, 2 cases of TLS-ERG, 32 cases of HOX11 were detected by Multiplex PCR in B-lineage leukemias. SIL-TAL1 had been found in 4 of 7 of T-lineage leukemias. CONCLUSIONS: Sixty-eight cases of ALL showed chromosomal aberrations. Multiplex PCR positivity was detected in 59 (50%) of the 116 ALL patients studied. Multiplex PCR combined with chromosomal analysis uncovered chromosomal abnormalities in 95 of 124 (77%) of ALL patients and supplemented each other in detecting chromosomal abnormalities.

[Epidemiological study on respiratory syncytial virus and its bronchopneumonia among children in Suzhou].

OBJECTIVE: To probe the epidemiological trend of respiratory syncytial virus (RSV) and cellular immunological change of RSV bronchopneumonia among children in Suzhou in the past five years. METHODS: 10,205 children with acute respiratory tract infection from January 2001 to December 2005 were enrolled into the study. Nasopharyngeal aspirates were obtained from the respiratory tract by aseptic vacuum aspiration. Direct immuno-fluorescence assay was employed to detect seven kinds of virus antigens including RSV antigen. CD3, CD4, CD8, CD19, CD16 and CD56 in peripheral blood mononuclear cells of 30 patients with RSV bronchopneumonia (1.5-24.0 months old group) were analyzed by flow cytometry analysis, and 15 normal infants (1.5-24.0 months old group) were enrolled as control group. RESULTS: The annual positive rate of RSV was 24.94%, 25.83%, 24.05%, 25.39% and 27.30% respectively from 2001 to 2005. It also found that the peak season for RSV infection was spring or winter (January to March or November to December). The positive rate of RSV was significantly higher in 1-12 months old group than that in > 12 months old group (chi2 = 97.320, P < 0.01), as well as the groups between 1-12 months old (chi2 = 7.804, P < 0.05, the highest positive rate was occurred at 3-6 months old group). The positive rate of RSV was significantly higher in boys than that in girls (chi2 = 9.693, P < 0.01). The percentages of CD3+, CD4+, CD8+ and NK (CD16 + 56)+ cells were significantly lower in RSV bronchopneumonia than those in control group (t = 3.199, P < 0.01; t = 2.215, P < 0.05; t = 2.619, P < 0.05 and t = 5.240, P < 0.01, respectively). While the percentage of CD19+ cells was significantly elevated in RSV bronchopneumonia than that in control group (t = 2.875, P < 0.01). CONCLUSION: RSV infection is of obvious seasonal changes. The younger the patient, the higher positive rates of RSV infection is, while and the cellular immunity function is lower. The effective measures for preventing RSV infection are important, especially for the infants. Further investigation is necessary to understand the causes of the variations for RSV infections between boys and girls.

[Detection of fusion genes resulting from chromosome abnormalities in childhood acute lymphoblastic leukemia].

OBJECTIVE: To detect the expression of the fusion genes resulting from chromosome abnormalities in childhood acute lymphoblastic leukemia(ALL) and its conformity to WHO classification. METHODS: Sixty-two children with ALL were investigated. The expression of fusion genes was determined by multiplex reverse transcription-polymerase chain reaction (RT-PCR), karyotyping (R band) and immunophenotyping (by flow cytometry) were also performed. RESULTS: Of the 62 patients, 23(37.1%) were found to carry 13 different fusion genes. The patients with immunophenotype of Pre-B-ALL were found to carry: TEL/AML1(3 cases); E2A/PBX1, E2A/HLF, TLS/ERG, MLL/AF4, MLL/AF9, MLL/AF10, MLL/AFX-MLL/AF6-MLL/ELL, MLL/AF6-MLL/ELL, dupMLL (one case for each); and HOX11 (6 cases). The patients with immunophenotype of Pre-T-ALL were found to carry: TAL1D (4 cases, one is also found to have HOX11 expression); and HOX11 (2 cases). The multiplex RT-PCR in combination with chromosome analysis revealed genetic abnormalities in 69.4%(43/62) of childhood ALL. CONCLUSION: Multiplex RT-PCR combined with chromosome analysis and immunophenotyping can provide reliable and helpful information for the diagnosis, therapy evaluation and prognosis prediction in childhood ALL, which may also serve as a basis on which to implement the criteria of WHO classification.

[Therapeutic effectiveness of CCLG-97 protocol on standard-risk childhood acute lymphoblastic leukemia].

OBJECTIVE: With the improvement of the diagnosis and treatment, the complete remission (CR) rate and the survival rate of childhood acute lymphoblastic leukemia have been increased in the recent 10 years. The objective of this study was to analyze the outcomes of 119 standard-risk childhood acute lymphoblastic leukemia (SR-ALL) patients, and explore how to improve the survival rate in ALL. METHODS: A total of 119 patients aged 14 months to 15 years were diagnosed as SR-ALL according to the Suggestion of Diagnosis And Treatment for Childhood Acute Leukemia-1993. Among them, seventy-nine were boys and 40 were girls. All of the patients were treated with the CCLG-97 protocol and were followed up for a period of 20 approximately 78 months. RESULTS: The complete remission rate reached 97.4% in four-week induction. Twenty-one patients were out of follow-up, comprising 63%, 14%, 10%, 8% and 5% of all subjects in 1998, 1999, 2000, 2001 and 2002, respectively. The overall survival rates were 93.3%, 90.2%, 88.0%, 85.0%, 85.0% and 85.0% in 1 year, 2 years, 3 years, 4 years and 5 years, respectively. Relapses occurred in 13 patients (13.8%). Among 9 isolated hematologic relapses, 5 patients (56%) were given irregular therapy, 2 did not reach CR within 4 weeks and relapsed 2 years later, 2 accepted regular therapy, 1 was of hypodiploidy and 1 T-ALL. Isolated central nervous system (CNS) relapse occurred in 4 patients (4.3%). Fifteen patients (12.6%) died, 5 of whom (4.2%) died of complications. CONCLUSION: Reinforcing administration and regular therapy are important to improve the long-term survival rate in childhood ALL. The clinical classification should be adjusted with the improvement of diagnostic methods. CCLG-97 protocol decreased the rate of the relapses in SR-ALL and didn't increase the rate of therapy-related death. High-dose methotrexate should be used in therapy and its dosage, usage and individualized therapeutic regimen should be further studied.

[A combined assay of multiplex RT-PCR and karyotypic analysis in childhood acute lymphoblastic leukemia].

OBJECTIVE: To study the value of combination assay of multiplex RT-PCR and karyotypic analysis in the diagnosis and classification of childhood acute lymphoblastic leukemia (ALL). METHODS: Fifty cases of childhood ALL patients were studied by multiplex RT-PCR in combination with R or G banding karyotype analysis. RESULTS: Of the 50 childhood ALL patients, 18 (36.0%) carried 11 types of fusion genes including E2A/PBX1, TEL/AML1, TLS/ERG, MLL/AF4, MLL/AF9, MLL/AF10, MLL/AFX, MLL/AF6, MLL/ELL, TAL1D, and HOX11, revealed by multiplex RT-PCR, and in 48 cases, 24 (57.1%) had chromosome abnormalities. Among the latter, numeral chromosome abnormalities and chromosome deletions accounted for 75.0% (18/24), while translocations 25.0% (6/24). The multiplex RT-PCR in combination with chromosome analysis could detect genetic abnormalities in 70% (35/50) of childhood ALL. CONCLUSIONS: Multiplex RT-PCR combined with chromosome analysis can enhance the detection rate of genetic abnormalities in childhood ALL. It provides reliable evidence for the diagnosis, classification and prognosis.

[Clinical and laboratory studies on childhood acute leukemia with 11q23 abnormalities].

OBJECTIVE: To investigate the interrelations among morphology, immunology, cytogenetics and clinical outcome in childhood acute leukemia with 11q23 abnormalities. METHODS: Eighteen patients with 11q23 abnormalities, from 320 childhood acute leukemia patients, were retrospectively analysed for cell morphology, flow cytometry, immunophenotyping, R-banding karyotype as well as clinical features and prognosis. Twenty cases of childhood AL with normal karyotype during the same period were used as control. RESULTS: The incidence of 11q23 abnormalities in our childhood acute leukemia patients was 5.63% including 14 acute lymphoblastic leukemia (ALL) and 4 acute myeloid leukemia (AML). Of 16 cases immunophenotypically tested, 13 expressed lymphoid antigens and 3 CD(34) and other myeloid antigens. Karyotype analysis disclosed the following abnormalities: t(4; 11)(q21; q23) in 6 cases, t(10; 11)(p13; q23) in 3, t(11; 19)(q23; p13) in one and del(11)(q23) in 6. The complete remission rate for these patients with 11q23 abnormalities was comparable to that of the control (72.2% vs 80.0%, P > 0.05), while the mortality rate in the former was significantly higher than that in the latter (61.1% vs 25.0%, P < 0.05). CONCLUSIONS: 11q23 abnormalities were mainly seen in childhood ALL and acute monocytic leukemia with unique prognostic features.