Marrie C. A. Bruin

Dexamethasone-based therapy for childhood acute lymphoblastic leukaemia : results of the prospective Dutch Childhood Oncology Group (DCOG) protocol ALL-9 (1997-2004)

BACKGROUND A population-based cohort of children aged 1-18 years with acute lymphoblastic leukaemia (ALL) was treated with a dexamethasone-based protocol (Dutch Childhood Oncology Group [DCOG] ALL-9). We aimed to confirm the results of the most effective DCOG ALL protocol for non-high-risk (NHR) patients to date (ALL-6), compare results with ALL-7 and ALL-8, and study prognostic factors in a non-randomised setting. METHODS From Jan 1, 1997, until Nov 1, 2004, patients with ALL were treated according to the ALL-9 protocol in eight Dutch academic centres with their affiliated peripheral hospitals. Patients were stratified into NHR and high risk (HR) groups. HR criteria were white-blood-cell count of 50,000 cells per microL or more, T-cell phenotype, mediastinal mass, CNS or testicular involvement, and Philadelphia chromosome or MLL rearrangement; patients who did not fulfil these criteria were deemed to be NHR. The NHR group was treated with a three-drug induction (dexamethasone, vincristine, and asparaginase) for 6 weeks, medium-dose methotrexate for 3 weeks, then maintenance therapy. HR patients received a four-drug induction (as for the NHR patients plus daunorubicin) for 6 weeks, high-dose methotrexate for 8 weeks, and two intensification courses before receiving maintenance therapy. Triple intrathecal medication was given 13 times in NHR patients, 15 times in HR patients (17 times for patients with initial CNS involvement). No patient received cranial irradiation. Maintenance therapy was given until 109 weeks for all patients and consisted of mercaptopurine and methotrexate for 5 weeks, alternated with dexamethasone and vincristine for 2 weeks. Kaplan-Meier analysis was done on an intention-to-treat basis with event-free survival as the primary endpoint. This trial is registered at trialregister.nl, number NTR460/SNWLK-ALL-9. FINDINGS 859 patients were recruited to the study. Complete remission was achieved in 592 (98.5%) of the 601 patients in the NHR group and 250 (96.9%) of the 258 in the HR group. Five patients in the NHR group and four in the HR group died during induction. Median follow-up for patients alive was 72.2 (range 4.8-132.7) months as of August, 2008. 5-year event-free survival was 81% (SE 1%) in all patients: 84% (2%) in NHR patients, and 72% (3%) in HR patients. Isolated CNS relapses occurred in 22 (2.6%) of 842 patients. In a multivariate analysis, DNA index was the strongest predictor of outcome (<1.16 vs >or=1.16; relative risk 0.42, 95% CI 0.22-0.78), followed by age (1-9 vs >or=10 years; 2.23, 1.60-3.11) and white-blood-cell count (<50,000 vs >or=50,000 cells per microL; 1.60, 1.13-2.26). INTERPRETATION The overall results of the dexamethasone-based DCOG ALL-9 protocol are better than those of our previous Berlin-Frankfurt-Münster-based protocols ALL-7 and ALL-8. The results for NHR patients were achieved with high cumulative doses of dexamethasone and vincristine, but without the use of anthracyclines, etoposide, cyclophosphamide, or cranial irradiation, therefore minimising the risk of side-effects. FUNDING Dutch Health Insurers.

Linkage of Familial Hemophagocytic Lymphohistiocytosis to 10q21-22 and Evidence for Heterogeneity

Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal recessive disorder characterized by the early onset of overwhelming activation of T lymphocytes and macrophages, invariably leading to death, in the absence of allogeneic bone marrow transplantation. Using genomewide genetic linkage analysis, we analyzed a group of 17 families with FHL and mapped a locus for FHL to the proximal region of the long arm of chromosome 10. Ten families showed no recombination with three tightly linked markers, D10S1650 (LOD score [Z]=6.99), D10S556 (Z=5.40), and D10S206 (Z=3.24), with a maximum multipoint LOD score of 11.22 at the D10S1650 locus. Haplotype analysis of these 10 families allowed us to establish D10S206 and D10S1665 as the telomeric and the centromeric flanking markers, respectively. Heterogeneity analysis and haplotype inspection of the remaining families confirmed that in seven families FHL was not linked to the 10q21-22 region, thus providing evidence for genetic heterogeneity of this condition.

Mutations in the thrombopoietin receptor, Mpl, in children with congenital amegakaryocytic thrombocytopenia

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare disorder of undefined aetiology. The disease presents with severe thrombocytopenia and absence of megakaryocytes in the bone marrow. Furthermore, CAMT patients may develop bone marrow aplasia. To obtain more insight into the mechanism underlying CAMT, five children were analysed. All patients had increased plasma thrombopoietin (Tpo) levels, indicating a platelet production defect. Bone marrow‐derived CD34+ stem cells from three patients were cultured in an in vitro liquid culture system to study megakaryocytopoiesis. CD34+ cells from two of the three patients failed to differentiate into megakaryocytes. The lack of megakaryocyte formation could imply that a defect in the c‐mpl gene, encoding the Tpo receptor, exists. Sequencing of c‐mpl revealed mutations in four of five patients. Three patients had point mutations and/or a deletion in the coding regions of c‐mpl. All point mutations led to an amino acid substitution or to a premature stop codon. In one patient, a homozygous mutation in the last base of intron 10 was found that resulted in loss of a splice site. This study showed that mutations in c‐mpl could be the cause of thrombocytopenia in CAMT in the majority of patients. Furthermore, Tpo has been shown to have an anti‐apoptotic effect on stem cells. Therefore, mutations in c‐mpl might not only affect megakaryocyte formation but may also impair stem cell survival, which could explain the occurrence of bone marrow failure as final outcome in patients with CAMT.

Prospective Study on Incidence, Risk Factors, and Long-Term Outcome of Osteonecrosis in Pediatric Acute Lymphoblastic Leukemia

PURPOSE We studied cumulative incidence, risk factors, therapeutic strategies, and outcome of symptomatic osteonecrosis in pediatric patients with acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS Cumulative incidence of osteonecrosis was assessed prospectively in 694 patients treated with the dexamethasone-based Dutch Child Oncology Group-ALL9 protocol. Osteonecrosis was defined by development of symptoms (National Cancer Institute grade 2 to 4) during treatment or within 1 year after treatment discontinuation, confirmed by magnetic resonance imaging. We evaluated risk factors for osteonecrosis using logistic multivariate regression. To describe outcome, we reviewed clinical and radiologic information after antileukemic treatment 1 year or more after osteonecrosis diagnosis. RESULTS Cumulative incidence of osteonecrosis at 3 years was 6.1%. After adjustment for treatment center, logistic multivariate regression identified age (odds ratio [OR], 1.47; P < .01) and female sex (OR, 2.23; P = .04) as independent risk factors. Median age at diagnosis of ALL in patients with osteonecrosis was 13.5 years, compared with 4.7 years in those without. In 21 (55%) of 38 patients with osteonecrosis, chemotherapy was adjusted. Seven patients (18%) underwent surgery: five joint-preserving procedures and two total-hip arthroplasties. Clinical follow-up of 35 patients was evaluated; median follow-up was 4.9 years. In 14 patients (40%), symptoms completely resolved; 14 (40%) had symptoms interfering with function but not with activities of daily living (ADLs; grade 2); seven (20%) had symptoms interfering with ADLs (grade 3). In 24 patients, radiologic follow-up was available; in six (25%), lesions improved/disappeared; in 13 (54%), lesions remained stable; five (21%) had progressive lesions. CONCLUSION Six percent of pediatric patients with ALL developed symptomatic osteonecrosis during or shortly after treatment. Older age and female sex were risk factors. After a median follow-up of 5 years, 60% of patients had persistent symptoms.

Platelet count, previous infection and FCGR2B genotype predict development of chronic disease in newly diagnosed idiopathic thrombocytopenia in childhood: results of a prospective study

About 25–30% of children with acute idiopathic thrombocytopenia (ITP) develop chronic disease. It is not well known which patient characteristics influence the course of the ITP. A prospective study in 60 children with newly diagnosed ITP was performed. The aim of the study was to identify patient characteristics at the onset of thrombocytopenia that predicts the progression to chronic ITP. Clinical data and blood samples were collected at several time points during the first 6 months of the disease. Variables predicting chronic disease, as calculated in a multivariate logistic regression analysis, were a platelet count >10 × 109/l at the onset [odds ratio (OR) 1·1, 95% confidence interval (CI) 1·01–1·14], the absence of infection shortly before the onset of the disease (OR 4·8, CI 1·16–19·57) and FGR2B‐232I/T genotype (OR 7·9, CI 0·96–65·27). The latter may point at an immune‐modulating role of FcγRIIb in ITP. Although only three patients had serious bleeds, 35 patients received immune‐modulating treatment for low platelet counts only. Seventeen patients were treated with intravenous immunoglobulin (IVIG) and 18 patients received corticosteroids. Patient variables did not differ between these treatment groups. However, patients receiving IVIG had significantly lower risk for chronic disease.

Clinical and laboratory predictors of chronic immune thrombocytopenia in children: a systematic review and meta-analysis

Childhood immune thrombocytopenia (ITP) is a rare autoimmune bleeding disorder. Most children recover within 6 to 12 months, but individual course is difficult to predict. We performed a systematic review and meta-analysis to identify predictors of chronic ITP. We found 1399 articles; after critical appraisal, 54 studies were included. The following predictors of chronic ITP in children, assessed in at least 3 studies, have been identified: female gender (odds ratio [OR] 1.17, 95% confidence interval [CI] 1.04-1.31), older age at presentation (age ≥11 years; OR 2.47, 95% CI 1.94-3.15), no preceding infection or vaccination (OR 3.08, 95 CI 2.19-4.32), insidious onset (OR 11.27, 95% CI 6.27-20.27), higher platelet counts at presentation (≥20 × 10(9)/L: OR 2.15, 95% CI 1.63-2.83), presence of antinuclear antibodies (OR 2.87, 95% 1.57-5.24), and treatment with a combination of methylprednisolone and intravenous immunoglobulin (OR 2.67, 95% CI 1.44-4.96). Children with mucosal bleeding at diagnosis or treatment with intravenous immunoglobulin alone developed chronic ITP less often (OR 0.39, 95% CI 0.28-0.54 and OR 0.71, 95% CI 0.52-0.97, respectively). The protective effect of intravenous immunoglobulin is remarkable and needs confirmation in prospective randomized trials as well as future laboratory studies to elucidate the mechanism of this effect.

Possible lower rate of chronic ITP after IVIG for acute childhood ITP an analysis from registry I of the Intercontinental Cooperative ITP Study Group (ICIS)

In children, one‐third of immune thrombocytopenic purpura (ITP) patients follow a chronic course. The present study investigated whether treatment with intravenous immunoglobulin (IVIG) at the time of diagnosis of ITP is of prognostic significance, using data from 1984 children entered in Registry I of the Intercontinental Cooperative ITP Study Group. A matched pairs analysis compared children with thrombocytopenia (platelet count <150 × 109/l) 6 months following diagnosis with children whose platelet count was normal 6 months after diagnosis. It was found that children initially treated with IVIG were more likely to have a normal platelet count 6 months after diagnosis than children not receiving IVIG (odds ratio 1·81; 95% confidence interval: 1·25–2·64). This result was independent of age, gender, country of origin, platelet count at diagnosis or infection preceding the diagnosis of ITP. In a similar analysis, comparing children with a platelet count <50 × 109/l 6 months after diagnosis with children whose platelet count was ≥50 × 109/l at that time point, the former group was less often treated with IVIG than with steroids (P = 0·02). Prospective studies are required to further explore this potential effect of IVIG.

Whole-body MRI, including diffusion-weighted imaging, for staging lymphoma: Comparison with CT in a prospective multicenter study

To compare whole‐body magnetic resonance imaging (MRI), including diffusion‐weighted imaging (DWI), to computed tomography (CT) for staging newly diagnosed lymphoma.

Childhood paroxysmal nocturnal haemoglobinuria (PNH), a report of 11 cases in the Netherlands

Paroxysmal nocturnal haemoglobinuria (PNH) is characterized by intravascular haemolysis, nocturnal haemoglobinuria, thrombotic events, serious infections and bone marrow failure. This acquired disease, caused by a deficiency of glycosylphosphatidylinositol (GPI) anchored proteins on the haematopoietic cells, is rare in children. We describe 11 Dutch paediatric PNH patients (median age: 12 years, range 9–17 years) diagnosed since 1983, seven cases associated with aplastic anaemia (AA), four with myelodysplastic syndrome (MDS). Presenting symptoms were haemorrhagic diathesis (n = 10), palor/tiredness (n = 8), dark urine (n = 1), fever (n = 1) and serious weight loss (n = 1). Treatment consisted of prednisolone (n = 7), anti‐thymocyte globulin (n = 3) and/or androgens (n = 5). Eventually, five patients received a bone marrow transplantation (BMT) (three matched unrelated donors/two matched family donors), of whom four are still alive. PNH, diagnosed by immunophenotypic GPI‐linked anchor protein analysis, should be considered in all children with AA or MDS. BMT should be considered as a therapeutic option in every paediatric PNH patient with BM failure.

Three parameters, plasma thrombopoietin levels, plasma glycocalicin levels and megakaryocyte culture, distinguish between different causes of congenital thrombocytopenia

Summary.  Fourteen children with congenital thrombocytopenia were analysed in order to unravel the mechanisms underlying their thrombocytopenia and to evaluate the value of new laboratory tests, namely measurement of plasma thrombopoietin (Tpo) and glycocalicin (GC) levels and analysis of megakaryocytopoiesis in vitro. Three groups of patients were included. The first group (n = 6) was diagnosed with congenital amegakaryocytic thrombocytopenia. They had no megakaryocytes in the bone marrow, three out of four patients showed no megakaryocyte formation in vitro, and all had high Tpo and low GC levels. Mutations in the thrombopoietin receptor gene, c‐mpl, were the cause. The second group of patients (n = 3) had normal Tpo and severely decreased GC levels. In bone marrow, normal to increased numbers of atypical, dysmature megakaryocytes were present. In vitro megakaryocyte formation was quantitatively normal. A defect in final megakaryocyte maturation and subsequent (pro‐)platelets may be the cause of the thrombocytopenia. The patients in the third group (n = 5) had Wiskott–Aldrich syndrome (WAS). They had normal Tpo and GC levels and normal megakaryocyte formation both in vivo and in vitro. This corresponded with the generally accepted hypothesis that thrombocytopenia in WAS is due to increased platelet turnover. In conclusion, different causes of congenital thrombocytopenia can be distinguished using three parameters: Tpo and GC plasma levels and in vitro analysis of megakaryocytopoiesis. Therefore, these parameters may be helpful in early diagnosis of different forms of congenital thrombocytopenia.