Role of CD81 and CD58 in minimal residual disease detection in pediatric B lymphoblastic leukemia.

INTRODUCTION: Minimal residual disease (MRD) in B lymphoblastic leukemia has been demonstrated to be a powerful predictor of clinical outcome in numerous studies in both children and adults. In this study, we evaluated 86 pediatric patients with both diagnostic and remission flow cytometry studies and compared expression of CD81, CD58, CD19, CD34, CD20, and CD38 in the detection of MRD. METHODS: We evaluated 86 patients with B lymphoblastic leukemia who had both diagnostic studies and remission studies for the presence of MRD using multicolor flow cytometry. We established our detection limit for identifying abnormal lymphoblasts using serial dilutions. We also compared flow cytometry findings with molecular MRD detection in a subset of patients. RESULTS: We found that we can resolve differences between hematogones and lymphoblasts in 85 of 86 cases using a combination of CD45, CD19, CD34, CD10, CD20, CD38, CD58, and CD81. Our detection limit using flow cytometry is 0.002% for detecting a population of abnormal B lymphoblasts. Comparison with MRD assessment by molecular methods showed a high concordance rate with flow cytometry findings. CONCLUSIONS: Our study highlights importance of using multiple markers to detect MRD in B lymphoblastic leukemia. Our findings indicate that including both CD58 and CD81 markers in addition to CD19, CD34, CD20, CD38, and CD10 are helpful in MRD detection by flow cytometry.

Effectiveness of antibacterial prophylaxis during induction chemotherapy in children with acute lymphoblastic leukemia.

BACKGROUND: Pediatric patients receiving induction chemotherapy for newly diagnosed acute lymphoblastic leukemia (ALL) are at high risk of developing life-threatening infections. We investigated whether uniform antibacterial guidelines, including mandatory antibacterial prophylaxis in afebrile patients during induction, decreases the incidence of microbiologically documented bacteremia. METHODS: Between 2012 and 2015, 230 patients with newly diagnosed ALL (aged 1-21) were enrolled on Dana-Farber Cancer Institute ALL Consortium Protocol 11-001 (DFCI 11-001). Induction therapy, regardless of risk group, included vincristine, prednisone, doxorubicin, methotrexate, and PEG-asparaginase. Afebrile patients received fluoroquinolone prophylaxis at the initiation of induction and those presenting with fever received broad-spectrum antibiotics; antibiotics were continued until blood count recovery. Rates of documented bacteremias and fungal infections on DFCI 11-001 were compared to those on the predecessor protocol (DFCI 05-001), which included the same induction phase without antibiotic prophylaxis guidelines. RESULTS: Sixty-six (28.7%) patients received fluoroquinolone prophylaxis, the remaining patients received broad-spectrum antibiotics. Twenty-four (36.4%) patients on prophylaxis developed fever and seven (10.6%) developed bacteremia. The overall rate of infection during induction on DFCI 11-001 was lower than on DFCl 05-001 (14.3% vs. 26.3%, P < 0.0001) due to a decreased rate of bacteremia (10.9% vs. 24.4%, P < 0.0001). The rate of fungal infections (4.8% vs. 3.6%) and induction death (0.9% vs. 2%) was not significantly different. CONCLUSION: For children with newly diagnosed ALL, uniform antibiotic administration until blood count recovery, including fluoroquinolone prophylaxis for afebrile patients, reduced the incidence of bacteremia during the induction phase. Larger, randomized studies should be performed to confirm these findings.

Polymorphisms of ABCC5 and NOS3 genes influence doxorubicin cardiotoxicity in survivors of childhood acute lymphoblastic leukemia.

Anthracyclines are efficient chemotherapy agents. However, their use is limited by anthracycline-induced cardiotoxicity (CT). We investigated the influence of polymorphisms in doxorubicin metabolic and functional pathways on late-onset CT as estimated by echocardiography in 251 childhood acute lymphoblastic leukemia (cALL) patients. Association analyses revealed a modulating effect of two variants: A-1629 T in ABCC5, an ATP-binding cassette transporter, and G894T in the NOS3 endothelial nitric oxide synthase gene. Individuals with the ABCC5 TT-1629 genotype had an average of 8-12% reduction of ejection (EF) and shortening fractions (SF; EF: P<0.0001, and SF: P=0.001, respectively). A protective effect of the NOS3 TT894 genotype on EF was seen in high-risk patients (P=0.02), especially in those who did not receive dexrazoxane (P=0.002). Analysis of an additional cohort of 44 cALL patients replicated the ABCC5 association but was underpowered for NOS3. In summary, we identified two biomarkers that may contribute to cALL anthracycline CT risk stratification.

Long-term outcome of a pediatric-inspired regimen used for adults aged 18-50 years with newly diagnosed acute lymphoblastic leukemia.

On the basis of the data suggesting that adolescents and young adult patients with acute lymphoblastic leukemia (ALL) have improved outcomes when treated on pediatric protocols, we assessed the feasibility of treating adult patients aged 18-50 years with ALL with the DFCI Pediatric ALL Consortium regimen utilizing a 30-week course of pharmacokinetically dose-adjusted E. coli L-asparaginase during consolidation. Between 2002 and 2008, 92 eligible patients aged 18-50 years were enrolled at 13 participating centers. Seventy-eight patients (85%) achieved a complete remission (CR) after 1 month of intensive induction therapy. With a median follow-up of 4.5 years, the 4-year disease-free survival (DFS) for the patients achieving a CR was 69% (95% confidence interval (CI) 56-78%) and the 4-year overall survival (OS) for all eligible patients was 67% (95% CI 56-76%). The 4-year DFS for the 64 patients who achieved a CR and were Philadelphia chromosome negative (Ph-) was 71% (95% CI 58-81%), and for all 74 Ph- patients the 4-year OS was 70% (95% CI 58-79%). We conclude that a pediatric-like treatment strategy for young adults with de novo ALL is feasible, associated with tolerable toxicity, and results in improved outcomes compared with historical regimens in young adult patients with ALL.

Repression of BIM mediates survival signaling by MYC and AKT in high-risk T-cell acute lymphoblastic leukemia.

Treatment resistance in T-cell acute lymphoblastic leukemia (T-ALL) is associated with phosphatase and tensin homolog (PTEN) deletions and resultant phosphatidylinositol 3'-kinase (PI3K)-AKT pathway activation, as well as MYC overexpression, and these pathways repress mitochondrial apoptosis in established T-lymphoblasts through poorly defined mechanisms. Normal T-cell progenitors are hypersensitive to mitochondrial apoptosis, a phenotype that is dependent on the expression of proapoptotic BIM. In a conditional zebrafish model, MYC downregulation induced BIM expression in T-lymphoblasts, an effect that was blunted by expression of constitutively active AKT. In human T-ALL cell lines and treatment-resistant patient samples, treatment with MYC or PI3K-AKT pathway inhibitors each induced BIM upregulation and apoptosis, indicating that BIM is repressed downstream of MYC and PI3K-AKT in high-risk T-ALL. Restoring BIM function in human T-ALL cells using a stapled peptide mimetic of the BIM BH3 domain had therapeutic activity, indicating that BIM repression is required for T-ALL viability. In the zebrafish model, where MYC downregulation induces T-ALL regression via mitochondrial apoptosis, T-ALL persisted despite MYC downregulation in 10% of bim wild-type zebrafish, 18% of bim heterozygotes and in 33% of bim homozygous mutants (P=0.017). We conclude that downregulation of BIM represents a key survival signal downstream of oncogenic MYC and PI3K-AKT signaling in treatment-resistant T-ALL.

Long-term results of Dana-Farber Cancer Institute ALL Consortium protocols for children with newly diagnosed acute lymphoblastic leukemia (1985-2000).

The Dana-Farber Cancer Institute (DFCI) acute lymphoblastic leukemia (ALL) Consortium has been conducting multi-institutional clinical trials in childhood ALL since 1981. The treatment backbone has included 20-30 consecutive weeks of asparaginase during intensification and frequent vincristine/corticosteroid pulses during the continuation phase. Between 1985 and 2000, 1457 children aged 0-18 years were treated on four consecutive protocols: 85-01 (1985-1987), 87-01 (1987-1991), 91-01 (1991-1955) and 95-01 (1996-2000). The 10-year event-free survival (EFS)+/-s.e. by protocol was 77.9+/-2.8% (85-01), 74.2+/-2.3% (87-01), 80.8+/-2.1% (91-01) and 80.5+/-1.8% (95-01). Approximately 82% of patients treated in the 1980s and 88% treated in the 1990s were long-term survivors. Both EFS and overall survival (OS) rates were significantly higher for patients treated in the 1990s compared with the 1980s (P=0.05 and 0.01, respectively). On the two protocols conducted in the 1990s, EFS was 79-85% for T-cell ALL patients and 75-78% for adolescents (age 10-18 years). Results of randomized studies revealed that dexrazoxane prevented acute cardiac injury without adversely affecting EFS or OS in high-risk (HR) patients, and frequently dosed intrathecal chemotherapy was an effective substitute for cranial radiation in standard-risk (SR) patients. Current studies continue to focus on improving efficacy while minimizing acute and late toxicities.

Silencing of the tumor suppressor gene FHIT is highly characteristic for MLL gene rearranged infant acute lymphoblastic leukemia.

MLL rearranged acute lymphoblastic leukemia (MLL) is an aggressive type of acute lymphoblastic leukemia (ALL), diagnosed predominantly in infants (<1 years of age). Since current chemotherapy fails in >50% of patients with MLL, new therapeutic strategies are desperately needed. For this, understanding the biological features characterizing MLL is necessary. Analysis of gene expression profiles revealed that the expression of the tumor suppressor gene FHIT is reduced in children with MLL rearranged ALL as compared to ALL patients carrying germ line MLL. This finding was confirmed by quantitative real-time PCR. In 100% of the infant MLL cases tested, methylation of the FHIT 5'CpG region was observed, resulting in strongly reduced mRNA and protein expression. In contrast, FHIT methylation in infant and non-infant ALL patients carrying germ line MLL was found in only approximately 60% (P< or =0.004). FHIT expression was restored upon exposing leukemic cells to the demethylating agent decitabine, which induced apoptosis. Likewise and more specifically, leukemic cell death was induced by transfecting MLL rearranged leukemic cells with expression vectors encoding wild-type FHIT, confirming tumor suppressor activity of this gene. These observations imply that suppression of FHIT may be required for the development of MLL, and provide new insights into leukemogenesis and therapeutic possibilities for MLL.

Excellent therapeutic efficacy and minimal late neurotoxicity in children treated with 18 grays of cranial radiation therapy for high-risk acute lymphoblastic leukemia: a 7-year follow-up study of the Dana-Farber Cancer Institute Consortium Protocol 87-01.

BACKGROUND: In the current study, the authors evaluated late neuropsychologic effects 7 years after diagnosis and the long-term survival in a cohort of patients treated for high-risk childhood acute lymphoblastic leukemia (ALL) with cranial radiation therapy. Efficacy and toxicity were evaluated in relation to patient age at diagnosis (age < or > or = 36 months). METHODS: Two hundred and one patients treated for high-risk ALL on the Dana-Farber Cancer Institute Consortium Protocol 87-01 were included, 147 of whom were in continuous complete disease remission and were eligible for cognitive testing. Sixty-one patients consented to undergo testing. All patients received 18 grays (Gy) of cranial radiation as a component of central nervous system treatment. RESULTS: For all 201 patients, the 5-year overall survival (% +/- the standard error) was 82% +/- 2 and the 5-year event-free survival (% +/- the standard error) was 75% +/- 3. Only two patients developed a central nervous system recurrence. Intelligence quotient (IQ) and memory were at the expected mean for age, but performance on a complex figure drawing task was found to be reduced. Children who were age < 36 months at the time of diagnosis were found to have an IQ in the average range, but showed verbal deficits. CONCLUSIONS: The results of the current study demonstrate excellent efficacy of therapy and relatively limited late neurotoxicity on a childhood ALL therapy protocol in which all evaluated patients had received 18 Gy of cranial radiation. Efficacious therapy that includes cranial radiation does not appear to necessarily incur a heightened risk for significant cognitive impairment.

Chemoattractants MDC and TARC are secreted by malignant B-cell precursors following CD40 ligation and support the migration of leukemia-specific T cells.

The use of tumor cells as vaccines in cancer immunotherapy is critically dependent on their capacity to initiate and amplify tumor-specific immunity. Optimal responses may require the modification of the tumor cells not only to increase their immunogenicity but also to improve their ability to recruit effector cells to the tumor sites or sites of tumor antigen exposure. It has been reported that CD40 cross-linking of acute lymphoblastic leukemia (ALL) cells significantly increases their immunogenicity and allows the generation and expansion of autologous antileukemia cytotoxic T lymphocytes. This study demonstrates that the CD40 ligation of these tumor cells also induces the secretion of the CC-chemokines MDC and TARC. Supernatants from malignant cells cultured in the presence of sCD40L promote the migration of activated T cells that express CCR4, the common specific receptor for MDC and TARC. More importantly, the supernatants from CD40-stimulated tumor cells also support the transendothelial migration of autologous CCR4(+) antileukemia T cells. Therefore, the results demonstrate that the delivery to leukemia cells of a single physiologic signal, that is, CD40 cross-linking, simultaneously improves tumor cell immunogenicity and induces potent chemoattraction for T cells. (Blood. 2001;98:533-540)

Bony morbidity in children treated for acute lymphoblastic leukemia.

PURPOSE: Corticosteroids are widely used in the treatment of acute lymphoblastic leukemia (ALL). To determine the frequency of corticosteroid-associated bony morbidity in children with ALL, we retrospectively evaluated the incidence of fractures and osteonecrosis (ON) on two consecutive pediatric ALL protocols. PATIENTS AND METHODS: One hundred seventy-six consecutive children were treated for ALL between 1987 and 1995 at the Dana-Farber Cancer Institute and Children's Hospital. Prednisone was used as the corticosteroid during postremission therapy from 1987 to 1991, and dexamethasone was used from 1991 to 1995. Medical records for all patients were reviewed to assess the occurrence of fractures and ON. RESULTS: With a median follow-up of 7.6 years, the 5-year cumulative incidence (CI) +/- SE of any bony morbidity for the 176 patients was 30% +/- 4%, with a 5-year CI of fractures of 28% +/- 3% and of ON of 7% +/- 2%. With multivariate analysis, independent predictors of bony morbidity included age 9 to 18 years at diagnosis (P <.01), male sex (P <.01), and treatment with dexamethasone (P =.01). Dexamethasone was associated with a higher risk of fractures (5-year CI, 36% +/- 5% v 20% +/- 4% with prednisone; P =.04), but not ON (P =.40). The 5-year event-free survival for the 176 patients was 79% +/- 3%. CONCLUSION: Children treated for ALL had a high incidence of fractures and ON. Older children, boys, and patients receiving dexamethasone were at increased risk for the development of bony morbidity. Future studies should attempt to minimize corticosteroid-associated bony morbidity without compromising clinical efficacy.

Improved response with higher corticosteroid dose in children with acute lymphoblastic leukemia.

PURPOSE: We investigated whether there was a dose-response relationship for the use of corticosteroids in childhood acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Three hundred sixty-nine patients, ages 1 to 18 years with ALL, were randomly assigned to receive one of four different doses of corticosteroid (prednisolone 40 mg/m(2)/d or dexamethasone 6, 18, or 150 mg/m(2)/d) administered as a 3-day, single-drug window before initiation of standard, multidrug induction chemotherapy. Corticosteroid drug response was measured by reduction in bone marrow blast counts and absolute peripheral blast counts after 3 days. Glucocorticoid receptor (GCR) number and the effective concentration of dexamethasone resulting in a 50% reduction of leukemic cell viability in vitro (EC-50) were evaluated at days 0 and 3. RESULTS: Increasing dexamethasone doses resulted in greater marrow blast response (P =.007), with a similar trend in peripheral-blood blast response. High-dose corticosteroid regimens (dexamethasone 18 or 150 mg/m(2)/d) elicited better responses than standard doses of dexamethasone or prednisone (bone marrow, P =.002; peripheral blasts, P =.05). Among patients treated with standard-dose corticosteroids, 38% with resistant (EC-50 > 10(-7)) peripheral blasts had a good response compared with 92% with sensitive (EC-50 < 10(-7)) peripheral blasts (P =.01). In contrast, there was no differential response according to EC-50 group after high-dose corticosteroids. Similarly, an association between response and GCR on peripheral-blood blasts was noted after standard-dose corticosteroid regimens but not after high-dose corticosteroid regimens. CONCLUSION: Response of ALL to glucocorticoid therapy increased with dose. Higher-dose corticosteroid treatment abrogated the effect of relative drug insensitivity and of low GCR on peripheral blasts.

Improved outcome for children with acute lymphoblastic leukemia: results of Dana-Farber Consortium Protocol 91-01.

The Dana-Farber Cancer Institute (DFCI) acute lymphoblastic leukemia (ALL) Consortium Protocol 91-01 was designed to improve the outcome of children with newly diagnosed ALL while minimizing toxicity. Compared with prior protocols, post-remission therapy was intensified by substituting dexamethasone for prednisone and prolonging the asparaginase intensification from 20 to 30 weeks. Between 1991 and 1995, 377 patients (age, 0-18 years) were enrolled; 137 patients were considered standard risk (SR), and 240 patients were high risk (HR). Following a 5.0-year median follow-up, the estimated 5-year event-free survival (EFS) +/- SE for all patients was 83% +/- 2%, which is superior to prior DFCI ALL Consortium protocols conducted between 1981 and 1991 (P =.03). There was no significant difference in 5-year EFS based upon risk group (87% +/- 3% for SR and 81% +/- 3% for HR, P =.24). Age at diagnosis was a statistically significant prognostic factor (P =.03), with inferior outcomes observed in infants and children 9 years or older. Patients who tolerated 25 or fewer weeks of asparaginase had a significantly worse outcome than those who received at least 26 weeks of asparaginase (P <.01, both univariate and multivariate). Older children (at least 9 years of age) were significantly more likely to have tolerated 25 or fewer weeks of asparaginase (P <.01). Treatment on Protocol 91-01 significantly improved the outcome of children with ALL, perhaps due to the prolonged asparaginase intensification and/or the use of dexamethasone. The inferior outcome of older children may be due, in part, to increased intolerance of intensive therapy.

Translocation (2;8)(p12;q24) associated with a cryptic t(12;21)(p13;q22) TEL/AML1 gene rearrangement in a child with acute lymphoblastic leukemia.

We report a case of childhood acute lymphoblastic leukemia with the simultaneous occurrence of a t(2;8)(p12;q24) typically associated with mature B cell or Burkitt leukemia, and a t(12;21)(p13;q22) exclusively associated with pre-B cell ALL. The lymphoblasts were characterized as L2 morphology by the French-American-British classification. However, there were atypical morphologic findings for L2 ALL, including vacuolization in some cells. The lymphoblasts were periodic acid-Schiff positive and myeloperoxidase negative. Immunophenotypic analysis revealed that the majority of lymphoblasts were TdT+, CD10+, CD19+, CD20-, and cytoplasmic mu+. These features were consistent with an immature pre-B cell leukemia phenotype with some characteristics of a mature B-cell leukemia. A t(2;8)(p12;q24)(p12;q24), characteristic of mature B-cell leukemia or Burkitt type leukemia, was detected by conventional cytogenetics with no other cytogenetic abnormalities. However, diagnostic peripheral blood and bone marrow specimens demonstrated simultaneous occurrence of a cryptic t(12;21)(p13;q22) by both FISH and RT-PCR. The simultaneous occurrence of these translocations in a pediatric patient have implications for the pathogenesis of leukemias with t(2;8)(p12;q24) as well as t(12;21)(p12;q22). Analysis of additional cases of leukemia with translocations involving the MYC locus on 8q24 will be required to determine the frequency of association with the cryptic t(12;21)(p13;22), and the prognostic significance of the simultaneous occurrence of the translocations.

Cognitive sequelae in children treated for acute lymphoblastic leukemia with dexamethasone or prednisone.

PURPOSE: The cognitive sequelae of treatment for childhood acute lymphoblastic leukemia (ALL) were compared in a group of patients who received dexamethasone during the intensification and maintenance phases of therapy with those in a historical control group for whom antileukemia therapy was similar, except that the corticosteroid component of therapy was prednisone. METHODS: Patients treated for ALL on Dana-Farber Cancer Institute protocols 87-01 (n = 44) and 91-01 (n = 23) were evaluated by standard cognitive and achievement tests. Corticosteroid therapy was delivered in 5-day pulses given every 3 weeks during intensification and continuation phases of therapy for a total of 2 years. RESULTS: Children treated on protocol 87-01 received prednisone at a dose of 40 mg/m2/d (standard risk, SR) or 120 mg/ m2/d (high risk, HR); those treated on protocol 91-01 received dexamethasone at a dose of 6 mg/m2 per day (SR) or 18 mg/m2 per day (HR). Children treated on protocol 91-01 performed less well on cognitive testing. Subsample analysis indicated that cranial radiation therapy and methotrexate dose did not account for differences in cognitive outcomes. CONCLUSIONS: The findings of this preliminary study are consistent with the hypothesis that dexamethasone therapy can increase risk for neurocognitive late effects in children treated for ALL and indicate that further investigation of this question is warranted.

Substituting dexamethasone for prednisone complicates remission induction in children with acute lymphoblastic leukemia.

BACKGROUND: The authors report the occurrence of fatal or near-fatal sepsis in 16 of 38 children with newly diagnosed acute lymphoblastic leukemia (ALL) treated with a new induction regimen that differed from its predecessor by the substitution of dexamethasone for prednisone. METHODS: The frequency of septic deaths among 38 children who received multiagent remission induction therapy, including dexamethasone (6 mg/m(2)) daily for 28 days (pilot protocol 91-01P), was compared with the frequency of septic deaths among children previously treated (protocol 87-01) and subsequently treated (protocol 91-01) in consecutive Dana-Farber Cancer Institute (DFCI) ALL trials with induction therapy that included 21 and 28 days of prednisone (40 mg/m(2)), respectively. Except for dexamethasone in protocol 91-01P, the remission induction agents used were identical in substance to those used in protocol 87-01. Protocol 91-01, the successor 91-01P, was also similar, with the exception of the deletion of a single dose of L-asparaginase. RESULTS: Sixteen of the 38 children (42%) treated on the DFCI 91-01P had documented gram positive or gram negative sepsis (17 episodes) during remission induction, including 4 toxic deaths (11%). In contrast, there were 4 induction deaths among 369 children (1%) treated on protocol 87-01 (P = 0.0035) and 1 induction death among 377 children (<1%) treated on protocol 91-01 (P = 0.0003). CONCLUSIONS: Substitution of dexamethasone for prednisone or methylprednisolone in an otherwise intensive conventional induction regimen for previously untreated children with ALL resulted in an alarmingly high incidence of septic episodes and toxic deaths. Awareness of this complication, considering that the substitution has no apparent benefit in the efficacy of remission induction, argues against its routine use in intensive induction regimens for children with ALL.

Results of Dana-Farber Cancer Institute Consortium protocols for children with newly diagnosed acute lymphoblastic leukemia (1981-1995).

The Dana-Farber Cancer Institute (DFCI) ALL consortium has been conducting clinical trials in childhood acute lymphoblastic leukemia (ALL) since 1981. The treatment backbone has included intensive, multi-agent remission induction, early intensification with weekly, high-dose asparaginase, cranial radiation for the majority of patients, frequent vincristine/ corticosteroid pulses during post-remission therapy, and for high-risk patients, doxorubicin during intensification. Between 1981 and 1995, 1,255 children with newly diagnosed ALL were evaluated on four consecutive protocols: 81-01 (1981-1985), 85-01 (1985-1987), 87-01 (1987-1991) and 91-01 (1991-1995). The 5-year event-free survival (EFS) rates (+/- standard error) for all patients by protocol were as follows: 74 +/- 3% (81-01), 78 +/- 3% (85-01), 77 +/- 2% (87-01) and 83 +/- 2% (91-01). The 5-year EFS rates ranged from 78 to 85% for patients with B-progenitor phenotype retrospectively classified as NCI standard-risk, 63-82% for NCI high-risk B-progenitor patients, and 70-79% for patients with T cell phenotype. Results of randomized studies revealed that neither high-dose methotrexate during induction (protocol 87-01) nor high-dose 6-mercaptopurine during intensification (protocol 91-01) were associated with improvement in EFS compared with standard doses. Current studies continue to focus on improving efficacy while minimizing acute and late toxicities.

Adoptive T-cell therapy for B-cell acute lymphoblastic leukemia: preclinical studies.

We have previously shown that leukemia-specific cytotoxic T cells (CTL) can be generated from the bone marrow of most patients with B-cell precursor acute leukemias. If these antileukemia CTL are to be used for adoptive immunotherapy, they must have the capability to circulate, migrate through endothelium, home to the bone marrow, and, most importantly, lyse the leukemic cells in a leukemia-permissive bone marrow microenvironment. We demonstrate here that such antileukemia T-cell lines are overwhelmingly CD8(+) and exhibit an activated phenotype. Using a transendothelial chemotaxis assay with human endothelial cells, we observed that these T cells can be recruited and transmigrate through vascular and bone marrow endothelium and that these transmigrated cells preserve their capacity to lyse leukemic cells. Additionally, these antileukemia T-cell lines are capable of adhering to autologous stromal cell layers. Finally, autologous antileukemia CTL specifically lyse leukemic cells even in the presence of autologous marrow stroma. Importantly, these antileukemia T-cell lines do not lyse autologous stromal cells. Thus, the capacity to generate anti-leukemia-specific T-cell lines coupled with the present findings that such cells can migrate, adhere, and function in the presence of the marrow microenvironment enable the development of clinical studies of adoptive transfer of antileukemia CTL for the treatment of ALL.

Induction failure in acute lymphoblastic leukemia of childhood.

BACKGROUND: Although it is widely accepted that failure to achieve complete remission (CR) portends a poor prognosis in childhood acute lymphoblastic leukemia (ALL), there is variability in the precise definition of induction failure and, to the authors' knowledge, few published data exist regarding the outcome of patients who are slow to achieve CR. METHODS: Between 1987-1995, 774 children with ALL were treated on 2 consecutive protocols and were evaluable to assess the time required to attain CR. The authors compared presenting characteristics and outcomes of patients based on their remission status after 1 month of induction chemotherapy: CR (n = 656), protracted hypoplasia (low peripheral blood counts and/or hypocellular marrow) (n = 95), and persistent leukemia (M2 or M3 bone marrow and/or evidence of extramedullary leukemia) (n = 23). The median follow-up was 5.2 years. RESULTS: Presenting features that predicted persistent leukemia included a leukocyte count > 100,000/mm3 and T-cell phenotype. Approximately 91% of patients with persistent leukemia and 100% with protracted hypoplasia eventually achieved CR. The 5-year event free survival (EFS) (95% confidence intervals [95% CI] in parentheses) for patients with persistent leukemia after 1 month was 16% (95% CI, 0%, 31%), which was significantly worse (P < 0.001) than that for those who achieved CR within 1 month (5-year EFS, 82%; 95% CI, 79%, 86%) and that for those with protracted hypoplasia (5-year EFS, 79%; 95% CI, 70%, 87%). For patients with persistent leukemia, there was no significant difference in survival based on bone marrow status (M2 or M3) after 1 month or on the number of induction cycles received before achieving CR. CONCLUSIONS: Patients with persistent leukemia at the end of 1 month of therapy have a dismal prognosis, regardless of when they subsequently achieve CR. More intensive and/or novel therapies should be considered for this subset of patients.

Prognostic significance of early response to a single dose of asparaginase in childhood acute lymphoblastic leukemia.

PURPOSE: The in vitro and in vivo efficacy of a single dose of asparaginase in children with newly diagnosed acute lymphoblastic leukemia and the correlation between in vitro and in vivo antileukemic response and long-term outcome were prospectively evaluated. PATIENTS AND METHODS: Two hundred fifty-one patients were randomized to receive 1 of 3 asparaginase preparations (Escherichia coli, Erwinia chrysanthemi [Erwinia], or pegaspargase). In vitro assessment of efficacy was expressed as the percent total cell kill (TCK), based on the number of viable cells found after 5 days of culture in the presence of asparaginase. In vivo leukemia cell kill (LCK) was calculated by comparing bone marrow cellularity and percent leukemic blasts in marrow obtained before and 5 days after treatment with a single dose of asparaginase. Acute toxicity was determined by clinical and laboratory assessment. RESULTS: There was equivalent cell kill with all three types of asparaginase. The mean in vitro TCKs for E. coli, Erwinia, and pegaspargase were 31%, 39%, and 36%, respectively (P = 0.63). The mean LCKs in marrow of patients exposed to E. coli, Erwinia, and pegaspargase were 69%, 74%, and 65%, respectively (P = 0.88). The lack of response to asparaginase in vitro predicted a higher risk for clinical relapse regardless of risk assignment (12 leukemic events among 21 in vitro nonresponders; 57%, P < 0.001). There was no difference in acute toxicity among the three asparaginase preparations. CONCLUSIONS: All three asparaginase preparations produced equivalent LCKs in in vitro and in vivo analyses. In vitro response to asparaginase provided a risk group-independent prognostic factor.