Clinical features and treatment outcome of childhood T-lineage acute lymphoblastic leukemia according to the apparent maturational stage of T-lineage leukemic blasts: a Children's Cancer Group study

PURPOSE: Leukemic cells from T-lineage acute lymphoblastic leukemia (ALL) patients are thought to originate from T-lymphocyte precursors corresponding to discrete stages of T-cell ontogeny. Here we sought to determine the influence of leukemic cell apparent maturational stage on treatment outcomes in pediatric T-lineage ALL. PATIENTS AND METHODS: From 1983 through 1993, 407 pediatric T-lineage ALL patients were enrolled onto two sequential series of risk-adjusted treatment protocols of the Children's Cancer Group. In the current analysis, T-lineage ALL patients were immunophenotypically classified as follows: CD7+ CD2- CD5- pro-thymocyte leukemia (pro-TL), CD7+ (CD2 or CD5)+ CD3- immature TL, and CD7+ CD2+ CD5+ CD3+ mature TL. RESULTS: Similar induction outcomes of 91.4%, 97.1%, and 98.3% were obtained by the pro-, immature, and mature TL groups, respectively. Four-year event-free survival (EFS) was lower for pro-TL patients (57.1%; SD = 8.4%,) compared with immature and mature TL patients (68.5%; SD = 3.5%; and 77.1%; SD = 4.0%, respectively) with an overall significance of .05 (log-rank test) or .04 (log-rank trend test). Relative hazards rates (RHR) were 2.11 and 1.22 for pro-TL and immature TL versus mature TL, respectively. Highly significant differences were found for overall survival (P = .005, log-rank test; P = .009, log-rank trend test). Multivariate analysis confirmed that the prognostic influence of ontogeny grouping was independent of that of other prognostic factors. CONCLUSION: Leukemic cells of the pro-TL maturation stage identify a small subgroup of T-lineage ALL patients who have a significantly worse EFS outcome than patients whose cells are of a more mature stage of development.     

Response of children with high-risk acute lymphoblastic leukemia treated with and without cranial irradiation: a report from the Children's Cancer Group

PURPOSE: Intensified intrathecal (i.t.) chemotherapy without cranial radiation therapy (CRT) prevents CNS relapse in children with low-risk and intermediate-risk acute lymphoblastic leukemia (ALL). In the current study, high-risk ALL patients who achieved a rapid early response (RER) to induction chemotherapy were randomized to receive intensive systemic chemotherapy and presymptomatic CNS therapy that consisted of either i.t. methotrexate (MTX) and CRT or intensified i.t. MTX alone. PATIENTS AND METHODS: Children (n = 636) with high-risk ALL (aged 1 to 9 years and WBC count > or = 50,000/microL or age > or = 10 years, excluding those with lymphomatous features) who achieved an RER (< or = 25% marrow blasts on day 7) to induction therapy and lacked CNS disease at diagnosis were randomized to receive systemic therapy with either i.t. MTX and CRT (regimen A, n = 317) or intensified i.t. MTX alone (regimen B, n = 319). RESULTS: Interim analysis in July 1993 revealed 3-year event-free survival (EFS) estimates of 82.1% +/- 4.0% (SD)and 70.4% +/- 4.2% for patients treated on regimens A and B, respectively (P = .004). As of January 1996, outcome had changed: 5-year EFS estimates were 69.1% +/- 3.4% and 75.0% +/- 2.7% for regimens A and B, respectively (P = 0.50). Marrow relapses comprised 57 events on regimen A and 43 events on regimen B. Fewer late events occurred on regimen B. CONCLUSION: For high-risk pediatric ALL patients who show an RER to induction therapy and are treated with systemic Children's Cancer Group (CCG)-modified Berlin-Frankfurt-Munster (BFM) chemotherapy, presymptomatic CNS therapy that consists of either i.t. MTX plus CRT or intensified i.t. MTX alone results in a similar 5-year EFS outcome. Furthermore, intensified i.t. MTX may protect against late bone marrow relapse.     

Augmented Berlin-Frankfurt-Munster therapy abrogates the adverse prognostic significance of slow early response to induction chemotherapy for children and adolescents with acute lymphoblastic leukemia and unfavorable presenting features: a report from the Children's Cancer Group

PURPOSE: Compared with previous Children's Cancer Group (CCG) acute lymphoblastic leukemia (ALL) trials, therapy based on the Berlin-Frankfurt-Munster (BFM) 76 trial has effected an improvement in event-free survival (EFS). In an attempt to improve EFS further, CCG investigators formulated an augmented BFM (A-BFM) regimen that provides prolonged, intensified postinduction chemotherapy relative to the CCG-modified BFM regimen. PATIENTS AND METHODS: We tested A-BFM in 101 patients with ALL and unfavorable presenting features that showed slow early response (SER) to induction therapy who attained remission on day 28. Their outcome was compared with that of 251 concurrent patients with unfavorable presenting features, a rapid early response to therapy (RER), and remission by day 28, treated with CCG-BFM with or without cranial radiation (CRT). RESULTS: The 4-year EFS rate from the end of induction for SER patients treated with A-BFM was 70.8% +/- 4.6%. Seventeen patients remain in continuous remission beyond 5 years. Vincristine (VCR) neurotoxicity developed in 50% of patients, but was rarely debilitating. Allergies to Escherichia coli L-asparaginase (L-ASP) occurred in 35% of patients. Avascular necrosis of bone (AVN) developed in 9% of patients. In comparison, a concurrent RER group treated with standard BFM +/- CRT had a 4-year EFS rate of 73.1% +/- 4.6%. CONCLUSION: The toxicity of A-BFM is significant, but acceptable. Compared with historical control SER patients treated with CCG-modified BFM, A-BFM therapy appears to produce a significant improvement in EFS. This is the first study to show that intensive chemotherapy, as given in the A-BFM regimen, can abrogate the adverse prognostic significance of SER.     

Results of the CCLSG high risk ALL 874 protocol in childhood acute lymphoblastic leukemia. Children's Cancer and Leukemia Study Group

One hundred and eighty eight children with acute lymphoblastic leukemia (ALL) were treated in a Children's Cancer and Leukemia Study Group high-risk ALL 874 study from April, 1987 to September, 1991. These patients received a four-drug induction regimen followed by the early consolidation regimen, cranial irradiation at 6 months of remission and three years of continuation therapy with rotational administration of four drugs. The patients were randomized into two regimens. In regimen A, the consolidation chemotherapy consisted of the intermediate dose cytosine arabinoside (Ara-C), cyclophosphamide (CPM) plus 6MP, and in regimen B, it consisted of high-dose Ara-C plus CPM. Regimen A was given to 106 patients and 82 patients received regimen B. The complete remission induction rate for regimen A and B was 89.4% (93/104) and 98.7% (78/79), respectively. The 3-year event-free-survival (EFS) rate was 70.6% for regimen A, which was higher than the 56.7% for regimen B. The 3-year EFS rate was 44.4% for the 53 patients with an initial leukocyte count > or = 10 x 10(4)/microliters and 72.2% for 132 patients with a leukocyte count < 10 x 10(4)/microliter. We considered that Ara-C plus L-asp, added to the conventional high-risk ALL 811 protocol, improved the prognosis of the high risk ALL patients. However, further intensive chemotherapy was required for improvement of the outcome of the patients with hyperleukocytosis (> or = 10 x 10(4)/microliters).     

Immunophenotypic and clinical features of T-cell receptor gammadelta+ T-lineage acute lymphoblastic leukaemia

The immunophenotypic and clinical features of TCR-gammadelta+ T-lineage acute lymphoblastic leukaemia (T-ALL) were prospectively analysed in 52 children with membrane CD3+ T-ALL. We observed a relatively high incidence of TCR-gammadelta+ T-ALL (26/52 patients). Leukaemic blasts from 22 children demonstrated TCR-alphabeta positivity, and simultaneous expression of the TCR-beta and -delta chain was found in four children. Clinical and haematological features of TCR-alphabeta and gammadelta+ T-ALL did not differ significantly, except that haemoglobin levels were significantly lower in TCR-gammadelta+ cases. Event-free survival at 4 years was significantly better in TCR-gammadelta+ compared with TCR-alphabeta+ T-ALL, but expression of TCR molecules did not emerge as an independent prognostic factor in multivariate analysis.     

Treatment of patients with acute lymphoblastic leukemia with bulky extramedullary disease and T-cell phenotype or other poor prognostic features: randomized controlled trial from the Children's Cancer Group

BACKGROUND: Children with acute lymphoblastic leukemia with multiple poor prognostic factors and who have a lymphomatous mass at diagnosis, whether of T- or non-T-immunophenotype, are at increased risk of short term remission and extramedullary recurrence, and are in need of better therapies. METHODS: Six hundred and ninety-four eligible patients ranging in age from 1-20 years were entered on the study. Sixty-five percent of the patients had T-cell immunophenotype. Of these, 678 were randomized to one of four regimens: Regimen A: Berlin-Frankfurt-Munster (BFM) 76/79; Regimen B: LSA2-L2 with cranial irradiation; Regimen C: LSA2-L2 without cranial irradiation; and Regimen D: the New York (NY) regimen. RESULTS: Complete remission was induced in 97% of patients. The overall event free survival (EFS) +/- the standard deviation was 60 +/- 4% 6 years after diagnosis, in contrast to 36 +/- 6% in a comparable historic group. The EFS of the 371 T-cell patients was 62 +/- 7%. EFS was best on the NY (67 +/- 7%) and the BFM (67 +/- 6%) arms. These were significantly better than the EFS on the 2 LSA-L2 regimens, with an EFS of 53 +/- 8% (Regimen B) and 42 +/- 11% (Regimen C) (P = 0.03 and 0.0003 for NY vs. Regimen B and NY vs. Regimen C; P = 0.01 and 0.0001 for BFM vs. Regimen B and BFM vs. Regimen C). Regimen C had a 3-fold greater central nervous system (CNS) recurrence rate than the identical chemotherapy Regimen B (16 +/- 5% vs. 6 +/- 4%; P = 0.02), although the difference in overall EFS did not reach the required level for significance. Testicular recurrence varied from 2-8% in comparison with 20% in the historic group. EFS was not influenced by age, gender, CNS disease at diagnosis, morphology, or immunophenotype. In addition to treatment regimen and early response rate, initial leukocyte count, hemoglobin level, liver, spleen, and lymph node enlargement, and the presence of a mediastinal mass had univariate prognostic influence on EFS. In multivariate analysis, only the kinetics of response, leukocyte count (unfavorably, P < 0.0001), and mediastinal mass status (favorably, P = 0.01) were prognostic. CONCLUSIONS: The adverse prognostic implications of lymphomatous ALL can be minimized by the NY and BFM regimens. Cranial irradiation resulted in better CNS disease control when added to the LSA2-L2 regimen, but did not improve the overall disease free survival. With improved systemic chemotherapy, there was no excess of lymph node, testicular, or other local recurrence without prophylactic irradiation to sites of initial bulk disease or to the testes.     

CD20在成年人急性B淋巴细胞白血病中的表达及其临床意义

目的 检测CD20在成年人急性B淋巴细胞白血病(B-ALL)的表达,探讨其与临床特点的相关性.方法 回顾性总结分析96例成年B-ALL患者CD20表达情况,结合其临床特性和治疗转归进行分析.结果 96例成年B-ALL患者中,CD20阳性29例(30.20%),CD20阴性67例(69.79%).CD20阳性组与阴性组男女比分别为1.42∶1和1.79∶1(x2=0.27,P＞0.05),中位年龄分别为28岁与23岁,肝脾及淋巴结浸润比例分别为44.83%和41.38%、40.30%和35.82%,髓系抗原表达比例分别为51.72%与56.72%,Ph染色体和bcr-abl融合基因阳性比例分别为24.14%与28.36%,4周内完全缓解率分别为73.08%与68.85%,差异均无统计学意义(P值均＞0.05).在复发率和3年总体生存率上,CD20阳性组分别为54.55%与14.80%,CD20阴性组分别为29.63%与37.30%,两组间差异有统计学意义(x2=0.42,x2=5.31;P值均＜0.05).结论 CD20在成年人B-ALL表达与临床特点无相关性,但对判断患者的预后有一定的指导意义.     

Prevention of CNS disease in intermediate-risk acute lymphoblastic leukemia: comparison of cranial radiation and intrathecal methotrexate and the importance of systemic therapy: a Childrens Cancer Group report

PURPOSE: This study (Childrens Cancer Group [CCG]-105) was designed in part to determine in a prospective randomized trial whether intrathecal methotrexate (IT MTX) administered during induction, consolidation, and maintenance could provide protection from CNS relapse equivalent to that provided by cranial radiation (CXRT) in children with acute lymphoblastic leukemia (ALL) and intermediate-risk features. PATIENTS AND METHODS: We randomized 1,388 children with intermediate-risk ALL to the two CNS regimens. They received either IT MTX at intervals throughout their course of therapy or CXRT (18 Gy) during consolidation with IT MTX during induction, consolidation, and delayed intensification. Systemic therapy was randomized to one of four treatment regimens derived from a regimen used by CCG in recent studies for this patient population and three more intensive regimens based on the Berlin-Frankfurt-Munster trials. RESULTS: Life-table estimates at 7 years show a 93% and 91% CNS relapse-free survival rate for the CXRT and IT MTX groups, respectively. The corresponding event-free survival (EFS) rates are 68% and 64%. The differences are not significant. Patients who received more intensive systemic therapy had a 94% CNS relapse-free survival rate on either CXRT or IT MTX, while patients who received standard systemic therapy had 90% and 80% rates for CXRT and IT MTX, respectively (P < .0001). Patients less than 10 years of age who received CXRT or IT MTX had 72% and 71% EFS rates if they received more intensive systemic therapy. Patients 10 years or older who received CXRT had an improved EFS (61% v 53%) with a more intensive systemic program. This was primarily due to fewer bone marrow relapses (P = .04). CONCLUSIONS: IT MTX during induction, consolidation, and maintenance provides protection from CNS relapse in patients with intermediate-risk ALL equivalent to that provided by CXRT if more intensive systemic therapy is given. The CNS relapse rate with either CXRT or IT MTX is in part dependent on the associated systemic therapy. For intermediate-risk patients less than 10 years of age, IT MTX with an intensified systemic regimen provided CNS prophylaxis comparable to that provided by CXRT, whereas older patients had fewer systemic relapses if they received CXRT.     

Mutational analysis of the N-ras gene in acute lymphoblastic leukemia: a study of 125 Japanese pediatric cases

Many antibiotic resistance mutations arise in pathogenic bacteria that harbor plasmids (R-plasmids). Resistance to third generation cephalosporins, for instance, largely occurs by one or more point mutations in plasmid bla genes that expand the resistance spectrum of beta-lactamases. Here I review relevant evidence underlying the worldwide emergence of extended spectrum beta-lactamases (ESBLs). The conclusion reached is that the origin of these resistance-conferring mutations cannot be explained by a series of single point mutation and selection events. Instead, highly advantageous stochastic processes might exist that generate alterations in the sequence or the conformation of particular regions in chromosomal or plasmid genomes such as bla, i.e., recombination or mutation. Several explanations for the origin of ESBLs are reviewed but direct experimental evidence to support or to invalidate them is still lacking. The cellular conditions under which ESBLs arise are unknown; however, involvement of nutritional stresses inside natural animal hosts and of plasmid conjugal functions appear likely.     

Cancer in human immunodeficiency virus-infected children: a case series from the Children's Cancer Group and the National Cancer Institute

PURPOSE: To describe the spectrum of malignancies in human immunodeficiency virus (HIV)-infected children and the clinical outcome of patients with these tumors. METHODS: We retrospectively surveyed the Children's Cancer Group (CCG) and the National Cancer Institute (NCI) for cases of cancer that occurred between July 1982 and February 1997 in children who were HIV seropositive before or at the time of cancer diagnosis. We used Kaplan-Meier survivorship curves, hazard function estimates, and Cox proportional hazards models to evaluate survival. RESULTS: Sixty-four children (39 boys, 25 girls) with 65 tumors were reported. Thirty-seven children (58%) acquired HIV infection vertically (median age at cancer diagnosis, 4.3 years); 22 children (34%) acquired HIV through transfusion of blood or blood products (median age at cancer diagnosis, 13.4 years). Forty-two children (65%) had non-Hodgkin's lymphoma (NHL). Eleven children (17%) had leiomyosarcomas (or leiomyomas), which are otherwise exceptionally rare in children. Other malignancies included acute leukemia (five children), Kaposi's sarcoma (KS; three children), Hodgkin's disease (two children), vaginal carcinoma in situ (one child), and tracheal neuroendocrine carcinoma (one child). Median survival after NHL diagnosis was 6 months (range, 1 day to 89 months) and after leiomyosarcoma was 12 months (range, 10 days to 19 months). The average monthly death rate after NHL diagnosis was 12% in the first 6 months, which decreased to about 2% thereafter. In contrast, the monthly death rate after leiomyosarcoma diagnosis increased from 5% in the first 6 months to about 20% thereafter. CONCLUSION: After NHL, leiomyosarcoma is the second leading cancer in children with HIV infection. Both cancers have high mortality rates; improved outcome for NHL, in particular, may depend on earlier diagnosis and therapy.     

Characteristics of children with acute nonlymphocytic leukemia in long-term continuous remission: a report for Childrens Cancer Study Group

Children and young adults less than 18 years of age with acute nonlymphocytic leukemia who remained in long term bone marrow and extramedullary remission for two years or longer since starting maintenance were compared to the remaining responders for the following characteristics: cell type, sex, age at diagnosis, race, pretreatment, white blood count, length of time from start to induction therapy to achievement of an M1 marrow, marrow rating at day 56 of therapy, marrow rating at the start of maintenance therapy, and specific study. Forty-eight patients of a group of 333 qualified as having long term remission (14.4%). Multivariant analysis indicated that patients between the ages of 3 and 10 years (p = 0.003) as well as the length of time to achieve an M1 marrow from the start of treatment (p = 0.03) were the only characteristics associated with achievement of a long term remission. Maintenance therapy was discontinued in 15 patients from 2.5 to 4.8 years after start of maintenance and all patients remained in bone marrow remission of periods from 0+ to 3.0+ years after stopping treatment. Of the 33 who have remained on a continuous maintenance therapy 12 have had bone marrow relapses. These data confirm the prognostic value of age and length of time to achieve remission during induction in acute nonlymphocytic leukemia and suggest that there may be no significant benefit from maintenance therapy continued beyond 2 years for patients in their initial remission.     

Prognostic significance of B-lineage leukemic cell growth in SCID mice: a Children's Cancer Group Study

Primary leukemic cells isolated from children (N = 681 ) with newly diagnosed B-lineage ALL enrolled on risk-adjusted treatment protocols of the Children's Cancer Group (CCG) were injected via the tail vein into 7-10 week old SCID mice. Leukemic cells from 104 of 681 patients (15.3%) were able to engraft and proliferate in one or more SCID mouse organs. These SCID+ patients were somewhat more likely than SCID patients to be older than 10 years of age (p = 0.03) and have WBC counts >20,000/microL (p = 0.04), but the groups were similar with respect to all other presenting features. Event-free survival (EFS) outcome at 3 years of follow-up was similar for SCID+ patients compared with SCID- patients (79.2%, SD = 5. 1% vs. 84.8%, SD = 2.8%; p = 0.20). Overall survival also was similar between the two groups (p = 0.93). This result was maintained within the subgroups of lower risk (N = 448) and higher risk (N = 233) patients. However, there were trends for poorer outcome among patients whose cells caused overt leukemia in SCID mice and infiltrated either 6 or more organs (p = 0.03), skeletal muscle (p = 0.0003), kidney (p = 0.05), or spleen (p = 0.06). Thus, engraftment of primary leukemic cells in SCID mice was not a significant predictor of outcome for the aggregate population of B-lineage ALL patients, the majority of whom were low risk, treated according to contemporary intensive chemotherapy programs of the CCG. However, development of disseminated overt leukemia and infiltration of SCID mouse skeletal muscle by primary leukemic cells from adjacent bone marrow may reflect a biologically more aggressive disease and identify patients at higher risk for treatment failure.     

Trisomy 21 in childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study (8602)

Of 1,036 children with newly diagnosed non-T, non-B acute lymphoblastic leukemia (ALL) and a demonstrated cytogenetic abnormality treated on the frontline Pediatric Oncology Group (POG) therapeutic trial 8602, there were 33 patients with trisomy 21 as the sole abnormality. Of these 33, 14 had Down syndrome (DS). Although the non-DS (NDS) trisomy 21 cases tended to be older than the DS cases, there were no other significant differences in clinicobiologic features nor in treatment outcomes between the DS and NDS groups, nor between the entire trisomy 21 group and the other chromosome abnormality group. Among NDS patients with +21 and one additional abnormality, +X, +16, -20, and structural abnormalities involving 6q or 12p were common findings. Kaplan-Meier event-free survival (EFS) curves showed a 4-year EFS of 80% (SE, 12%) in NDS trisomy 21 cases, 71% (SE, 22%) in DS cases with trisomy 21 as the sole abnormality, and 69% (SE, 2%) in cases with other chromosome abnormalities. Trisomy 21 as a sole acquired abnormality in NDS patients suggests a good prognosis.     

Survival after relapse in childhood acute lymphoblastic leukemia: impact of site and time to first relapse--the Children''s Cancer Group Experience

After cardioversion from atrial fibrillation (AF) many patients develop early recurrence of the arrhythmia. While these patients may be appropriate for immediate prophylaxis against AF recurrence their identification at the time of cardioversion is not possible. Since the signal-averaged P wave (SAPW) is abnormal in individuals with atrial arrhythmia, we assessed its utility for predicting early AF recurrence after cardioversion. Seventy-five cardioversions in 31 patients were evaluated. The mean age was 59 (range 28-79) years; 26 were male. Fifty-eight cardioversions were internal using low energy biphasic DC shocks delivered via electrodes placed in the right atrial appendage and coronary sinus. P wave specific signal averaging was performed at 3 and 24 hours after each cardioversion to estimate filtered P wave duration and energy from 20, 40, and 60 to 150 Hz. Follow-up was by regular clinic visits and transtelephonic ECG monitoring. Early recurrence of AF (prospectively defined as sinus rhythm duration < 1 week) occurred after 30 cardioversions. No differences were found in any P wave variable measured at 3 hours between these cardioversions and those that resulted in a longer duration of sinus rhythm. Paired 3- and 24-hour signal-averaged data were available in 47 cardioversions. There were significant falls in P wave energy from 3 to 24 hours after 31 cardioversions that resulted in sinus rhythm for > 1 week, (P40: 3 hours 11.2 [+/- 1.5] micro V2.s, 24 hours 8.6 [+/- 1.2] micro V2.s, P < 0.001), but not following the 16 after which AF returned within 1 week (P40: 3 hours 9.0 [+/- 1.2] micro V2.s, 24 hours 8.5 [+/- 1.2 micro V2.s, P = NS). A fall in P40 of > 25% had a positive predictive accuracy for maintenance of sinus rhythm of 87%; negative predictive accuracy was only 37%. Similar falls in P wave energy occurred after cardioversions that resulted in longer term (> 4 weeks) sinus rhythm, but not in those that did not. However, the predictive accuracy of a fall in P40 was less (positive predictive accuracy 38%, negative predictive accuracy 62%). Patients with relapsing permanent AF who remain in sinus rhythm for at least 1 week after cardioversion show a fall in P wave energy within the first 24 hours. However, in these patients the technique does not predict recurrent AF within 1 week nor sinus rhythm > 4 weeks. These observations suggest persistent disordered atrial activation as a mechanism for early recurrence of AF after cardioversion.     

Clinical characteristics and treatment results of acute promyelocytic leukemia in children (Children's Cancer and Leukemia Study Group)

The clinical characteristics and treatment outcome in 40 children with acute promyelocytic leukemia (APL) treated at institutions participating in the Children's Cancer and Leukemia Study Group (CCLSG) were studied retrospectively. The median age at diagnosis was 8 years old. Bleeding diathesis was the predominant presenting symptom (90%), associated with laboratory findings of disseminated intravascular coagulation. Hepatomegaly, splenomegaly and lymphadenopathy were observed in 35%, 10%, and 15% of the cases, respectively. The median WBC count was 4.25 x 10(9)/l. Anemia (hemoglobin < 8 g/dl) and thrombocytopenia (< 30 x 10(9)/l) were present in more than half of the patients. Cytogenetic studies demonstrated the characteristic 15; 17 translocation in about 90% of the patients analyzed. Induction therapy consisted of cytosine arabinoside and an anthracycline, with or without other agents. Twenty-nine patients (73%) achieved complete remission (CR) while early fatal hemorrhage was the predominant cause of induction failure. The survival rates continued to decrease (28% at 3 years, 24% at 5 years, and 7.9% at 10 years) due to late marrow relapses. Anthracycline cardiotoxicity was fatal in three patients in remission. These clinical features of childhood APL should be taken into account in the development of new protocols.