Comparative analysis between cytomorphology and flow cytometry methods in central nervous system infiltration assessment in oncohematological patients.

INTRODUCTION: Oncohematological patients require the evaluation for possible infiltration of the central nervous system (CNS) by neoplastic cells at diagnosis and/or during the monitoring of the chemotherapeutic treatment. Morphological analysis using conventional microscopy is considered the method of choice to evaluate the cerebrospinal fluid (CSF) samples, despite technical limitations. OBJECTIVE: This study aimed to compare the performance of the cytomorphology and flow cytometric immunophenotyping (FC) in the detection of CNS infiltration. METHOD: We evaluated 520 CSF samples collected from 287 oncohematological patients for whom the detection of neoplastic cells was simultaneously requested by cytomorphology and FC. RESULTS: Laboratory analyses revealed 435/520 (83.7%) conclusive results by the two methods evaluated, among which 385 (88.5%) were concordant. Discordance between the methods was observed in 50/435 (11.5%) samples, 45 (90%) being positive by FC. Furthermore, the FC defined the results in 69/72 (95.8%) inconclusive samples by cytomorphology. The positivity of FC was particularly higher among hypocellular samples. Among 431 samples with a cell count of < 5/µL, the FC identified neoplastic cells in 75 (17.4%), while the cytomorphology reported positive results in 26 (6%). Among the samples that presented adequate cell recovery for evaluation by both methods (506/520), the comparative analysis between FC and cytomorphology revealed a Kappa coefficient of 0.45 (CI: 0.37-0.52), interpreted as a moderate agreement. CONCLUSION: The data showed that the CSF analysis by FC helps in the definition of CNS infiltration by neoplastic cells, particularly in the cases with dubious morphological analysis or in the evaluation of samples with low cellularity.

Comparative analysis between cytomorphology and flow cytometry methods in central nervous system infiltration assessment in oncohematological patients

ABSTRACT Introduction Oncohematological patients require the evaluation for possible infiltration of the central nervous system (CNS) by neoplastic cells at diagnosis and/or during the monitoring of the chemotherapeutic treatment. Morphological analysis using conventional microscopy is considered the method of choice to evaluate the cerebrospinal fluid (CSF) samples, despite technical limitations. Objective This study aimed to compare the performance of the cytomorphology and flow cytometric immunophenotyping (FC) in the detection of CNS infiltration. Method We evaluated 520 CSF samples collected from 287 oncohematological patients for whom the detection of neoplastic cells was simultaneously requested by cytomorphology and FC. Results Laboratory analyses revealed 435/520 (83.7%) conclusive results by the two methods evaluated, among which 385 (88.5%) were concordant. Discordance between the methods was observed in 50/435 (11.5%) samples, 45 (90%) being positive by FC. Furthermore, the FC defined the results in 69/72 (95.8%) inconclusive samples by cytomorphology. The positivity of FC was particularly higher among hypocellular samples. Among 431 samples with a cell count of < 5/μL, the FC identified neoplastic cells in 75 (17.4%), while the cytomorphology reported positive results in 26 (6%). Among the samples that presented adequate cell recovery for evaluation by both methods (506/520), the comparative analysis between FC and cytomorphology revealed a Kappa coefficient of 0.45 (CI: 0.37-0.52), interpreted as a moderate agreement. Conclusion The data showed that the CSF analysis by FC helps in the definition of CNS infiltration by neoplastic cells, particularly in the cases with dubious morphological analysis or in the evaluation of samples with low cellularity.

30 Years of Experience with Non-Hodgkin Lymphoma in Children and Adolescents: a retrospective cohort study.

OBJECTIVE: Describe the clinical and demographic characteristics of pediatric patients with non-Hodgkin's lymphoma (NHL) enrolled in a tertiary unit of Pediatric Hematology between 1982-2015. PATIENTS AND METHODS: A retrospective cohort study of 140 patients aged 16 years or less with NHL. Demographic characteristics, data on diagnosis, and outcomes were analyzed. The overall survival (OS) analysis and stratification by the most frequent histological subtypes were performed using the Kaplan-Meier method. RESULTS: One hundred and thirty-six patients with de novo NHL and four with NHL as a second malignancy were analyzed. The median age at diagnosis was 6.4 years (interquartile range, 4.2 to 11.1 years); 101 patients were males. Four patients had primary immunodeficiency, four had human immunodeficiency virus, two post-liver transplantation, and one had autoimmune lymphoproliferative syndrome. The most frequent histological type was NHL of mature B- cell (B-NHL-B; 67.1%), with Burkitt's lymphoma being the most frequent subtype, and lymphoblastic lymphoma (LBL, 21.4%). The main clinical manifestation at the diagnosis was abdominal tumors (41.4%). During the follow-up time, 13 patients relapsed, but five of them reached a second remission. Thirty-five patients died, and 103 remained alive in clinical remission. No contact was possible for two patients. The OS at 5 years was 74.5% (± 3.8%). The OS estimated for patients with LBL, NHL-B, and the remaining was 80.4%±7.9%, 72.8%±4.7%, and 74.5%±11%, respectively (P = 0.58). CONCLUSION: Our results are comparable with cohorts from other middle-income countries.

30 Years of Experience with Non-Hodgkin Lymphoma in Children and Adolescents: a retrospective cohort study

SUMMARY OBJECTIVE Describe the clinical and demographic characteristics of pediatric patients with non-Hodgkin's lymphoma (NHL) enrolled in a tertiary unit of Pediatric Hematology between 1982-2015. PATIENTS AND METHODS A retrospective cohort study of 140 patients aged 16 years or less with NHL. Demographic characteristics, data on diagnosis, and outcomes were analyzed. The overall survival (OS) analysis and stratification by the most frequent histological subtypes were performed using the Kaplan-Meier method. RESULTS One hundred and thirty-six patients with de novo NHL and four with NHL as a second malignancy were analyzed. The median age at diagnosis was 6.4 years (interquartile range, 4.2 to 11.1 years); 101 patients were males. Four patients had primary immunodeficiency, four had human immunodeficiency virus, two post-liver transplantation, and one had autoimmune lymphoproliferative syndrome. The most frequent histological type was NHL of mature B- cell (B-NHL-B; 67.1%), with Burkitt's lymphoma being the most frequent subtype, and lymphoblastic lymphoma (LBL, 21.4%). The main clinical manifestation at the diagnosis was abdominal tumors (41.4%). During the follow-up time, 13 patients relapsed, but five of them reached a second remission. Thirty-five patients died, and 103 remained alive in clinical remission. No contact was possible for two patients. The OS at 5 years was 74.5% (± 3.8%). The OS estimated for patients with LBL, NHL-B, and the remaining was 80.4%±7.9%, 72.8%±4.7%, and 74.5%±11%, respectively (P = 0.58). CONCLUSION Our results are comparable with cohorts from other middle-income countries.

RESUMO OBJETIVO Descrever as características clínicas e demográficas de pacientes pediátricos com linfoma não Hodgkin (LNH) em uma unidade terciária de Hematologia Pediátrica entre 1982-2015. PACIENTES E MÉTODOS Estudo de coorte retrospectivo de dados de prontuários de 140 pacientes com idade até 16 anos com LNH. Características demográficas e dados relativos ao diagnóstico e evolução foram analisados. A sobrevida global (SG) e estratificada pelos subtipos histológicos mais frequentes foi analisada pelo método de Kaplan-Meier. RESULTADOS Dados de 136 pacientes com LNH de novo e quatro com LNH como segunda neoplasia foram analisados. A mediana de idade ao diagnóstico foi 6,4 anos (intervalo interquartil: 4,2 a 11,1 anos); 101 pacientes eram meninos. Onze pacientes apresentavam imunodeficiência (quatro primária, quatro secundária ao vírus da imunodeficiência humana adquirida, dois pós-transplante hepático e um com síndrome linfoproliferativa autoimune). Os tipos histológicos mais frequentes foram o LNH de células B madura (LNH-B, 67,1% dos pacientes), sendo o linfoma de Burkitt o subtipo mais frequente, e o linfoma linfoblástico (LL, 21,4%). A principal manifestação clínica ao diagnóstico foi massa abdominal (41,4%). A mediana de seguimento dos sobreviventes foi 7,7 anos (intervalo interquartil: 3,3 a 10,9 anos). Treze pacientes recidivaram (cinco alcançaram segunda remissão clínica), 35 faleceram, 103 permanecem vivos em remissão completa e dois perderam o seguimento. A probabilidade de SG em cinco anos foi 74,5%±3,8%. Para os pacientes com LL, LNH-B e os demais, a SG foi 80,4%±7,9%, 72,8%±4,7% e 74,5%±11%, respectivamente (P=0,58). CONCLUSÃO Nossos resultados são comparáveis aos de outros países de renda média.

Cytogenetic abnormalities, WHO classification, and evolution of children and adolescents with acute myeloid leukemia

ABSTRACT Objectives: To describe cytogenetic and molecular abnormalities observed in children and adolescents with acute myeloid leukemia (AML), classify AML according to the World Health Organization (WHO) classifications from 2008 and 2016, and evaluate the prognosis according to clinical characteristics and cytogenetic abnormalities. Methods: A retrospective longitudinal study was performed on a population of 98 patients with AML, aged up to 16 years, seen in a single hospital from 2004 to 2015. Results: Among the 80 patients for whom it was possible to analyze the karyotype, 78.7% had chromosomal changes, the most frequent being t(15;17)(q22;q21). Of the 86 patients for whom we had cytogenetic or molecular data, making it possible to classify their AML according to the WHO classification, 52.3% belonged to the group with recurrent genetic abnormalities, 22% to the "AML not otherwise specified" group, 18.6% to the group with myelodysplasia-related cytogenetic changes, and 7% to the group with Down syndrome-related leukemia. Five-year overall survival (OS) for the whole group was 49.7% ± 5.2%. In the univariate and multivariate analyses, patients with myelodysplasia-related cytogenetic changes (OS 28.1% ± 12.2%) and those with "AML not otherwise specified" (OS 36.1% ± 11.2%) had an unfavorable prognosis when compared to patients with AML with recurrent genetic abnormalities (OS 71% ± 5.8%) and patients with Down syndrome-related AML (OS 83% ± 15.2%, p = 0.011). Conclusions: The results corroborate the importance of cytogenetic abnormalities as a prognostic factor and indicate the need for cooperative and prospective studies to evaluate the applicability of the WHO classification in the pediatric population.

Comparison between flow cytometry and standard PCR in the evaluation of MRD in children with acute lymphoblastic leukemia treated with the GBTLI LLA - 2009 protocol.

Minimal residual disease (MRD) monitoring is of prognostic importance in childhood acute lymphoblastic leukemia (ALL). The detection of immunoglobulin and T-cell receptor gene rearrangements by real-time quantitative PCR (RT-PCR) is considered the gold standard for this evaluation. However, more accessible methods also show satisfactory performance. This study aimed to compare MRD analysis by four-color flow cytometry (FC) and qualitative standard PCR on days 35 and 78 of chemotherapy and to correlate these data with patients' clinical characteristics. Forty-two children with a recent diagnosis of ALL, admitted to a public hospital in Brazil for treatment in accordance with the Brazilian Childhood Cooperative Group for ALL Treatment (GBTLI LLA-2009), were included. Bone marrow samples collected at diagnosis and on days 35 and 78 of treatment were analyzed for the immunophenotypic characterization of blasts by FC and for the detection of clonal rearrangements by standard PCR. Paired analyses were performed in 61/68 (89.7%) follow-up samples, with a general agreement of 88.5%. Disagreements were resolved by RT-PCR, which evidenced one false-negative and four false-positive results in FC, as well as two false-negative results in PCR. Among the prognostic factors, a significant association was found only between T-cell lineage and MRD by standard PCR. These results show that FC and standard PCR produce similar results in MRD detection of childhood ALL and that both methodologies may be useful in the monitoring of disease treatment, especially in regions with limited financial resources.

Cytogenetic abnormalities, WHO classification, and evolution of children and adolescents with acute myeloid leukemia.

OBJECTIVES: To describe cytogenetic and molecular abnormalities observed in children and adolescents with acute myeloid leukemia (AML), classify AML according to the World Health Organization (WHO) classifications from 2008 and 2016, and evaluate the prognosis according to clinical characteristics and cytogenetic abnormalities. METHODS: A retrospective longitudinal study was performed on a population of 98 patients with AML, aged up to 16 years, seen in a single hospital from 2004 to 2015. RESULTS: Among the 80 patients for whom it was possible to analyze the karyotype, 78.7% had chromosomal changes, the most frequent being t(15;17)(q22;q21). Of the 86 patients for whom we had cytogenetic or molecular data, making it possible to classify their AML according to the WHO classification, 52.3% belonged to the group with recurrent genetic abnormalities, 22% to the "AML not otherwise specified" group, 18.6% to the group with myelodysplasia-related cytogenetic changes, and 7% to the group with Down syndrome-related leukemia. Five-year overall survival (OS) for the whole group was 49.7%±5.2%. In the univariate and multivariate analyses, patients with myelodysplasia-related cytogenetic changes (OS 28.1%±12.2%) and those with "AML not otherwise specified" (OS 36.1%±11.2%) had an unfavorable prognosis when compared to patients with AML with recurrent genetic abnormalities (OS 71%±5.8%) and patients with Down syndrome-related AML (OS 83%±15.2%, p=0.011). CONCLUSIONS: The results corroborate the importance of cytogenetic abnormalities as a prognostic factor and indicate the need for cooperative and prospective studies to evaluate the applicability of the WHO classification in the pediatric population.

Use of the Polymerase Chain Reaction as a Complementary Method for the Detection of Central Nervous System Involvement in Children and Adolescents with Acute Lymphoblastic Leukemia.

BACKGROUND: Cytological analysis of the cerebrospinal fluid (CSF) remains the most widely used method for diagnosing central nervous system (CNS) involvement in acute lymphoblastic leukemia (ALL). This study aimed at evaluating the use of polymerase chain reaction (PCR), in comparison to other methods, for the assessment of the presence of blast cells in the CSF at the time of diagnosis of ALL. METHODS: This was a prospective, single-centre, study enrolling all patients up to the age of 18 years who were admitted to a university hospital between November 2011 and November 2014 with a diagnosis of ALL and from whom it was possible to draw a sufficient amount of CSF for analysis by conventional cytology (CT), immunophenotyping (IMP), and PCR. RESULTS: A total of 46 CSF samples from 44 ALL pediatric patients were included. CT was performed in all samples, IMP in 44, and PCR in 34. Thirteen (28.2%) samples showed positive results: two by CT, four by IMP, four by PCR, and three by both IMP and PCR. CONCLUSIONS: The results of this study showed that PCR should be considered a complementary method for the evaluation of the CSF in ALL patients at diagnosis.

Immunophenotyping of the cerebrospinal fluid as a prognostic factor at diagnosis of acute lymphoblastic leukemia in children and adolescents.

This study aimed at evaluating the use of immunophenotyping (IMP) in the identification of blast cells in the cerebrospinal fluid (CSF) of children and adolescents with acute lymphoblastic leukemia (ALL). Sixty-seven patients aged 18 years or younger were included. Fifty-five CSF samples were analyzed at initial diagnosis and 17 at the time of relapse. A cytological analysis (CA) was performed in all 72 samples, while IMP was done in 63. Blasts were identified in only three samples by CA, whereas all three samples were found negative by IMP, one of which had no isolation of nucleated cells after centrifugation. Among the samples analyzed by IMP, 11 showed a positive blast count, two of which had been inconclusive using CA. No equivalence was found between CA and IMP results (p = 0.55). CSF IMP positivity was not associated with other risk factors for ALL relapse. Among the 55 patients included at the time of diagnosis of ALL, eight relapsed during follow-up. Considering the cases of central nervous system (CNS) relapse, one of the patients belonged to the CSF IMP-positive group (11%) at diagnosis, and the other two cases, to the IMP-negative (5%) group. Detection of CSF blast cells using IMP was associated with a worse overall (p < 0.0001) and event-free survival (p < 0.0001). These results show that CSF IMP may be a useful additional method to conventional CA in the diagnosis of CNS involvement in ALL, and for the identification of high-risk subgroups that would benefit from an intensified therapy.

Current Strategies for the Detection of Minimal Residual Disease in Childhood Acute Lymphoblastic Leukemia.

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Current treatment strategies for childhood ALL result in long-term remission for approximately 90% of patients. However, the therapeutic response is worse among those who relapse. Several risk stratification approaches based on clinical and biological aspects have been proposed to intensify treatment in patients with high risk of relapse and reduce toxicity on those with a greater probability of cure. The detection of residual leukemic cells (minimal residual disease, MRD) is the most important prognostic factor to identify high-risk patients, allowing redefinition of chemotherapy. In the last decades, several standardized research protocols evaluated MRD using immunophenotyping by flow cytometry and/or real-time quantitative polymerase chain reaction at different time points during treatment. Both methods are highly sensitive (10(-3) a 10(-5)), but expensive, complex, and, because of that, require qualified staff and frequently are restricted to reference centers. The aim of this article was to review technical aspects of immunophenotyping by flow cytometry and real-time quantitative polymerase chain reaction to evaluate MRD in ALL.

Hemophagocytic lymphohistiocytosis: a case series of a Brazilian institution.

OBJECTIVE: To describe the clinical and laboratory presentation of hemophagocytic lymphohistiocytosis in children treated at a referral institution. METHODS: A retrospective descriptive study was carried out of seven children diagnosed with hemophagocytic lymphohistiocytosis between 2010 and 2012. The criteria for diagnosis were those proposed by the Histiocyte Society. When indicated, immunochemotherapy was prescribed according to the HLH94 and HLH2004 protocols of the Histiocyte Society. RESULTS: The patients' ages at diagnosis ranged from one month to nine years. All patients had splenomegaly, fever, anemia, thrombocytopenia, hyperferritinemia and hypertriglyceridemia. Bone marrow hemophagocytosis was detected in six patients. In six cases, infectious diseases triggered the syndrome. In two cases, associated with visceral leishmaniasis, remission was achieved after treatment of the underlying infection. Three patients, who had Epstein-Barr-related hemophagocytic lymphohistiocytosis, required treatment with immunochemotherapy. They are alive and in remission; one patient had symptoms of juvenile rheumatoid arthritis and another, who was suspected of having primary hemophagocytic lymphohistiocytosis, entered into remission after bone marrow transplantation. Two deaths (28.6%) occurred in patients with suspected primary hemophagocytic lymphohistiocytosis; one whose clinical picture was triggered by cytomegalovirus infection did not respond to immunochemotherapy and the other died before any specific treatment was provided. CONCLUSION: As reported before, hemophagocytic lymphohistiocytosis has a multifaceted presentation with nonspecific signs and symptoms. In secondary forms, remission may be achieved by treating the underlying disease. In the primary forms, remission may be achieved with immunochemotherapy, but bone marrow transplantation is required for cure.

Hemophagocytic lymphohistiocytosis: a case series of a Brazilian institution

Objective: To describe the clinical and laboratory presentation of hemophagocytic lymphohistiocytosis in children treated at a referral institution. Methods: A retrospective descriptive study was carried out of seven children diagnosed with hemophagocytic lymphohistiocytosis between 2010 and 2012. The criteria for diagnosis were those proposed by the Histiocyte Society. When indicated, immunochemotherapy was prescribed according to the HLH94 and HLH2004 protocols of the Histiocyte Society. Results: The patients' ages at diagnosis ranged from one month to nine years. All patients had splenomegaly, fever, anemia, thrombocytopenia, hyperferritinemia and hypertriglyceridemia. Bone marrow hemophagocytosis was detected in six patients. In six cases, infectious diseases triggered the syndrome. In two cases, associated with visceral leishmaniasis, remission was achieved after treatment of the underlying infection. Three patients, who had Epstein–Barr-related hemophagocytic lymphohistiocytosis, required treatment with immunochemotherapy. They are alive and in remission; one patient had symptoms of juvenile rheumatoid arthritis and another, who was suspected of having primary hemophagocytic lymphohistiocytosis, entered into remission after bone marrow transplantation. Two deaths (28.6%) occurred in patients with suspected primary hemophagocytic lymphohistiocytosis; one whose clinical picture was triggered by cytomegalovirus infection did not respond to immunochemotherapy and the other died before any specific treatment was provided. Conclusion: As reported before, hemophagocytic lymphohistiocytosis has a multifaceted presentation with nonspecific signs and symptoms. In secondary forms, remission may be achieved by treating the underlying disease. In the primary forms, remission may be achieved with immunochemotherapy, but bone marrow transplantation is required for cure...

Detecção de células com fenótipo HPN por citometria de fluxo, utilizando análise multiparamétrica / Detection of PNH cells by flow cytometry, using multiparameter analysis

Introduction: The laboratory diagnosis of paroxysmal nocturnal hemoglobinuria (PNH), disease that is categorized by reduced synthesis of glycosylphosphatidylinositol (GPI) anchor, is based on the detection of blood cells deficient in GPI-anchored proteins by flow cytometry. PNH clones have been detected in patients with aplastic anaemia (AA) and myelodysplastic syndrome (MDS), with therapeutic implications. Objectives: To validate a sensitive assay for detection of GPI-anchored protein-deficient cells, by flow cytometry, and to analyze the clone frequency in AA and MDS patients. Methods: Samples from 20 AA patients, 30 MDS patients and 20 adult volunteers (control group) were analyzed using monoclonal antibodies to CD16, CD24, CD55 and CD59 (neutrophils); CD14 and CD55 (monocytes); CD55 and CD59 (erythrocytes); besides fluorescent aerolysin reagent (FLAER) (neutrophils and monocytes) and lineage markers. The proportions of PNH cells detected in neutrophils and monocytes, using different reagent combinations, were compared by analysis of variance (ANOVA) and Pearson's correlation. Results: PNH cells were detected in five (25%) AA patients, and the proportions of PNH cells varied from 0.14% to 94.84% of the analyzed events. PNH cells were not detected in the MDS patients. However, by the analysis of these samples, it was possible to identify the technical challenges caused by the presence of immature and dysplastic circulating cells. FLAER showed clear distinction of GPI-deficient cells. Conclusion: Multiparameter flow cytometry analysis offers high sensitivity and accuracy in the detection of subclinical PNH clones. FLAER shows excellent performance in detection of PNH neutrophils and monocytes...

Introdução: O diagnóstico laboratorial da hemoglobinúria paroxística noturna (HPN), doença caracterizada por deficiência de síntese da molécula de ancoragem glicosilfosfatidilinositol (GPI), baseia-se na detecção de células sanguíneas deficientes em proteínas ancoradas ao GPI, por citometria de fluxo. Clones de células com fenótipo HPN podem ser detectados em pacientes com anemia aplásica (AA) e síndrome mielodisplásica (SMD), com implicações terapêuticas. Objetivos: Validar técnica sensível para detecção de células HPN, por citometria de fluxo, e avaliar a frequência dos clones em pacientes com AA e SMD. Métodos: Amostras de 20 pacientes com AA, 30 pacientes com SMD e 20 voluntários (controles) foram analisadas, utilizando anticorpos monoclonais anti-CD16, CD24, CD55 e CD59 (neutrófilos); CD14 e CD55 (monócitos); e CD55 e CD59 (hemácias); além do reagente de aerolisina fluorescente (FLAER) (neutrófilos e monócitos) e marcadores de linhagem celular. A comparação do tamanho dos clones HPN detectados em neutrófilos e monócitos, pelas diferentes combinações de reagentes, foi realizada por análise de variância (ANOVA) e correlação de Pearson. Resultados: Em cinco (25%) pacientes com AA foram identificadas células HPN, em proporções entre 0,14% e 94,84% dos eventos analisados. O clone não foi detectado nos pacientes com SMD. Contudo, a análise dessas amostras permitiu evidenciar as dificuldades técnicas secundárias à presença de células imaturas e displásicas circulantes. O reagente FLAER propiciou separação precisa das células alteradas. Conclusão: A análise multiparamétrica por citometria de fluxo apresenta sensibilidade...

Gene rearrangement study for minimal residual disease monitoring in children with acute lymphocytic leukemia.

OBJECTIVE: To detect markers for minimal residual disease monitoring based on conventional polymerase chain reaction for immunoglobulin, T-cell receptor rearrangements and the Sil-Tal1 deletion in patients with acute lymphocytic leukemia. METHODS: Fifty-nine children with acute lymphocytic leukemia from three institutions in Minas Gerais, Brazil, were prospectively studied. Clonal rearrangements were detected by polymerase chain reaction followed by homo/heteroduplex clonality analysis in DNA samples from diagnostic bone marrow. Follow-up samples were collected on Days 14 and 28-35 of the induction phase. The Kaplan-Meier and multivariate Cox methods were used for survival analysis. RESULTS: Immunoglobulin/T-cell receptor rearrangements were not detected in 5/55 children screened (9.0%). For precursor-B acute lymphocytic leukemia, the most frequent rearrangement was IgH (72.7%), then TCRG (61.4%), and TCRD and IgK (47.7%); for T-acute lymphocytic leukemia, TCRG (80.0%), and TCRD and Sil-Tal deletion (20.0%) were the most common. Minimal residual disease was detected in 35% of the cases on Day 14 and in 22.5% on Day 28-35. Minimal residual disease on Day 28-35, T-acute lymphocytic leukemia, and leukocyte count above 50 x 10(9)/L at diagnosis were bad prognostic factors for leukemia-free survival in univariate analysis. Relapse risk for minimal residual disease positive relative to minimal residual disease negative children was 8.5 times higher (95% confidence interval: 1.02-70.7). CONCLUSION: Immunoglobulin/T-cell receptor rearrangement frequencies were similar to those reported before. Minimal residual disease is an independent prognostic factor for leukemia-free survival, even when based on a non-quantitative technique, but longer follow-ups are needed.

Gene rearrangement study for minimal residual disease monitoring in children with acute lymphocytic leukemia

OBJECTIVE To detect markers for minimal residual disease monitoring based on conventional polymerase chain reaction for immunoglobulin, T-cell receptor rearrangements and the Sil-Tal1 deletion in patients with acute lymphocytic leukemia. METHODS Fifty-nine children with acute lymphocytic leukemia from three institutions in Minas Gerais, Brazil, were prospectively studied. Clonal rearrangements were detected by polymerase chain reaction followed by homo/heteroduplex clonality analysis in DNA samples from diagnostic bone marrow. Follow-up samples were collected on Days 14 and 28-35 of the induction phase. The Kaplan-Meier and multivariate Cox methods were used for survival analysis. RESULTS Immunoglobulin/T-cell receptor rearrangements were not detected in 5/55 children screened (9.0%). For precursor-B acute lymphocytic leukemia, the most frequent rearrangement was IgH (72.7%), then TCRG (61.4%), and TCRD and IgK (47.7%); for T-acute lymphocytic leukemia, TCRG (80.0%), and TCRD and Sil-Tal deletion (20.0%) were the most common. Minimal residual disease was detected in 35% of the cases on Day 14 and in 22.5% on Day 28-35. Minimal residual disease on Day 28-35, T-acute lymphocytic leukemia, and leukocyte count above 50 x 109/L at diagnosis were bad prognostic factors for leukemia-free survival in univariate analysis. Relapse risk for minimal residual disease positive relative to minimal residual disease negative children was 8.5 times higher (95% confidence interval: 1.02-70.7). CONCLUSION Immunoglobulin/T-cell receptor rearrangement frequencies were similar to those reported before. Minimal residual disease is an independent prognostic factor for leukemia-free survival, even when based on a non-quantitative technique, but longer follow-ups are needed.

Incidence and risk factors for central nervous system relapse in children and adolescents with acute lymphoblastic leukemia.

BACKGROUND: Despite all the advances in the treatment of childhood acute lymphoblastic leukemia, central nervous system relapse remains an important obstacle to curing these patients. This study analyzed the incidence of central nervous system relapse and the risk factors for its occurrence in children and adolescents with acute lymphoblastic leukemia. METHODS: This study has a retrospective cohort design. The studied population comprised 199 children and adolescents with a diagnosis of acute lymphoblastic leukemia followed up at Hospital das Clinicas, Universidade Federal de Minas Gerais (HC-UFMG) between March 2001 and August 2009 and submitted to the Grupo Brasileiro de Tratamento de Leucemia da Infância - acute lymphoblastic leukemia (GBTLI-LLA-99) treatment protocol. RESULTS: The estimated probabilities of overall survival and event free survival at 5 years were 69.5% (± 3.6%) and 58.8% (± 4.0%), respectively. The cumulative incidence of central nervous system (isolated or combined) relapse was 11.0% at 8 years. The estimated rate of isolated central nervous system relapse at 8 years was 6.8%. In patients with a blood leukocyte count at diagnosis ≥ 50 x 10(9)/L, the estimated rate of isolated or combined central nervous system relapse was higher than in the group with a count < 50 x 10(9)/L (p-value = 0.0008). There was no difference in cumulative central nervous system relapse (isolated or combined) for the other analyzed variables: immunophenotype, traumatic lumbar puncture, interval between diagnosis and first lumbar puncture and place where the procedure was performed. CONCLUSIONS: These results suggest that a leukocyte count > 50 x 10(9)/L at diagnosis seems to be a significant prognostic factor for a higher incidence of central nervous system relapse in childhood acute lymphoblastic leukemia.