Equal frequency of TEL/AML1 rearrangements in children with acute lymphoblastic leukemia with and without Down syndrome

Constitutional trisomy 21 is the most prominent predisposing factor to childhood leukemia, whereas the t(12;21)(p13;q22) with its molecular genetic counterpart, the TEL/AML1 fusion gene, is the most common acquired chromosomal rearrangement in childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1⁺ BCP ALL is extremely low in patients with Down syndrome (DS). To further investigate this issue in a population-based fashion, the authors retrospectively assessed the number of DS patients with a TEL/AML1⁺ ALL in two consecutive Austrian ALL multicenter trials. Accordingly, they were able to analyze 8 of 10 individuals with DS and a BCP ALL, two of whom who suffered from a TEL/AML1⁺ leukemia. Based on this observation they concluded that individuals with BCP leukemia and a constitutional trisomy 21 may have similar likelihood to have a TEL/AML1 rearrangement as BCP ALL patients without this specific predisposing factor.     

Histiocytosis following T-acute lymphoblastic leukemia: a BFM study

The coincidence of T-cell acute lymphoblastic leukemia (T-ALL) and histiocytic disorders, including hemophagocytic lymphohistiocytosis (T-ALL/HLH) and Langerhans cell histiocytosis (T-ALL/LCH), is very seldom and is usually associated with a dismal prognosis. Retrospective statistical analysis of all T-ALL patients, who have been registered in the BFM-ALL trials from 1981 - 2001 and who have subsequently developed a LCH/HLH, in order to identify any common risk factors pre-disposing to the synchronous occurrence of both disorders. Six out of 971 T-ALL patients had either HLH or LCH ( approximately 0.03% of treated T-ALL/year). The mean age at diagnosis of T-ALL/HLH/LCH was significantly lower than in the remaining T-ALL group (4.05 +/- 0.59 vs 8.82 +/- 0.14 years; p = 0.000). The mean initial leukocyte count was higher than in the non-HLH/LCH group (270,700 +/- 60,677 microl(-1) vs 134,141 +/- 5,663 microl(-1); p = 0.074). No hemophagocytosis was seen in the initial bone marrow (BM) smears. Five of 6 patients obtained a good prednisone response (GPR) at day 8 in peripheral blood with <5% blasts at day 15 in BM and all cases were in complete remission (CR) at day 33. The mean time until development of the histiocytosis was 17.95 months (range 2.5 - 33 months). Four patients developed a HLH and 2 a LCH. All patients with HLH showed a multi-organ involvement, while the LCH patients had only local disease. Only the LCH patients survived, while all patients with HLH died. The authors recommend a close follow-up for at least 3 years after diagnosis in younger T-ALL patients with high initial leukocyte count.     

Outcome of children with primary resistant or relapsed non-Hodgkin lymphoma and mature B-cell leukemia after intensive first-line treatment: a population-based analysis of the Austrian Cooperative Study Group

BACKGROUND: Children and adolescents with Non-Hodgkin lymphoma (NHL) and mature B-cell leukemia (B-ALL) have an excellent prognosis with contemporary chemotherapy stratified according to the histologic subtype and clinical stage of disease. However, a small subset of patients does not respond to front-line therapy or suffers from an early relapse. PROCEDURE: A retrospective analysis was performed to assess the incidence, treatment, and outcome of all children with relapsed or progressed NHL and B-ALL diagnosed in Austria between 1986 and 2003 (n = 22/234). RESULTS: Nine of 140 (6.5%) patients with B-cell NHL/B-ALL (relapse, n = 6; progress, n = 3) failed initial treatment. Four of them underwent a hematopoietic stem cell transplantation (HSCT) as second-line therapy, two patients received intensive chemotherapy alone and in three patients treatment was palliative. Eight of the nine patients died of their disease. Four of 65 (6%) patients with lymphoblastic lymphoma (LBL) (relapse, n = 2; progress, n = 2) had a treatment failure. High-dose chemotherapy followed by HSCT was performed in two of the four patients; another two patients received chemotherapy alone. Three of the four patients died of resistant disease. Nine of 29 (31%) patients with anaplastic large cell lymphoma (ALCL) (relapse, n = 7; progress, n = 2) failed first-line therapy. Six underwent a HSCT (autologous, n = 3; allogeneic, n = 3) and are currently in second complete remission. Treatment of the other three patients consisted of chemotherapy alone-they all died of tumor progression. CONCLUSIONS: Conclusively, patients with early relapsed and progressive B-cell neoplasia or LBL have a very poor prognosis with current treatment approaches, while those with ALCL have a respectable chance to achieve a sustained complete second remission with high-dose chemotherapy and HSCT.     

CD20 up-regulation in pediatric B-cell precursor acute lymphoblastic leukemia during induction treatment: setting the stage for anti-CD20 directed immunotherapy

CD20 is expressed in approximately one- half of pediatric acute lymphoblastic leukemia (ALL) cases with B-cell precursor (BCP) origin. We observed that it is occasionally up-regulated during treatment. To understand the impact of this on the potential effectiveness of anti-CD20 immunotherapy, we studied 237 CD10(+) pediatric BCP-ALL patients with Berlin-Frankfurt-Munster (BFM)-type therapy. We analyzed CD20 expression changes from diagnosis to end-induction, focusing on sample pairs with more than or equal to 0.1% residual leukemic blasts, and assessed complement-induced cytotoxicity by CD20-targeting with rituximab in vitro. CD20-positivity significantly increased from 45% in initial samples to 81% at end-induction (day 15, 71%). The levels of expression also increased; 52% of cases at end-induction had at least 90% CD20(pos) leukemic cells, as opposed to 5% at diagnosis (day 15, 20%). CD20 up-regulation was frequent in high-risk patients, patients with high minimal residual disease at end-induction, and patients who suffered later from relapse, but not in TEL/AML1 cases. Notably, up-regulation occurred in viable cells sustaining chemotherapy. In vitro, CD20 up-regulation significantly enhanced rituximab cytotoxicity and could be elicited on prednisolone incubation. In conclusion, CD20 up-regulation is frequently induced in BCP-ALL during induction, and this translates into an acquired state of higher sensitivity to rituximab. This study was registered at http://www.clinicaltrials.gov as #NCT00430118.     

Die neue Serie “Hämato-Onkologie” stellt sich vor

Krebs im Kindes- und Jugendalter ist an und für sich eine ?u?erst seltene Erkrankung. Die Inzidenz b?sartiger Erkrankungen liegt im europ?ischen Raum bei 12 bis 16 Erkrankungen pro 100.000 Kinder unter einem Alter von 15 Jahren. In ?sterreich erkranken j?hrlich etwa 250 Kinder im Alter von bis 15 Jahren an einer malignen Tumorerkrankung. Bis zu 50 Prozent dieser Krankheiten treten in den ersten fünf Lebensjahren auf. Die relative H?ufigkeit der verschiedenen Krebserkrankungen variiert betr?chtlich, da zum Beispiel akute Leuk?mien und die typischen embryonalen Tumoren, wie das Nephroblastom, Neuroblastom oder Retinoblastom bevorzugt im Kleinkindesalter diagnostiziert werden, w?hrend das Hodgkin Lymphom oder Knochentumoren, wie das Osteosarkom und Ewing Sarkom bevorzugte Erkrankungen des zweiten Lebensjahrzehnts darstellen.     

qPET – a quantitative extension of the Deauville scale to assess response in interim FDG-PET scans in lymphoma

Background

Interim FDG-PET is used for treatment tailoring in lymphoma. Deauville response criteria consist of five ordinal categories based on visual comparison of residual tumor uptake to physiological reference uptakes. However, PET-response is a continuum and visual assessments can be distorted by optical illusions.

Objectives

With a novel semi-automatic quantification tool we eliminate optical illusions and extend the Deauville score to a continuous scale.

Patients and methods

SUV_peak of residual tumors and average uptake of the liver is measured with standardized volumes of interest. The qPET value is the quotient of these measurements. Deauville scores and qPET-values were determined in 898 pediatric Hodgkin’s lymphoma patients after two OEPA chemotherapy cycles.

Results

Deauville categories translate to thresholds on the qPET scale: Categories 3, 4, 5 correspond to qPET values of 0.95, 1.3 and 2.0, respectively. The distribution of qPET values is unimodal with a peak representing metabolically normal responses and a tail of clearly abnormal outliers. In our patients, the peak is at qPET = 0.95 coinciding with the border between Deauville 2 and 3. qPET cut values of 1.3 or 2 (determined by fitting mixture models) select abnormal metabolic responses with high sensitivity, respectively, specificity.

Conclusions

qPET methodology provides semi-automatic quantification for interim FDG-PET response in lymphoma extending ordinal Deauville scoring to a continuous scale. Deauville categories correspond to certain qPET cut values. Thresholds between normal and abnormal response can be derived from the qPET-distribution without need for follow-up data. In our patients, qPET < 1.3 excludes abnormal response with high sensitivity.     

Limited stage I disease is not necessarily indicative of an excellent prognosis in childhood anaplastic large cell lymphoma

Data on incidence, characteristics, and prognosis in stage I childhood anaplastic large cell lymphoma are scarce. Of 463 patients enrolled in the international ALCL99 trial, 36 (8%) had stage I disease and were treated with a prephase chemotherapy, followed by either 3 chemotherapy courses in case of initial complete resection (6 patients) or otherwise by 6 courses of chemotherapy (30 patients). Disease localization was to the peripheral lymph nodes in 26, soft tissue mass in 8, and solitary bone and bronchial disease in 1 patient each. Of the 6 patients with complete resection, none experienced relapse, whereas of the 30 remaining stage I patients, 9 (30%) relapsed, including in all cases a new site of disease involvement and including 3 of 5 anaplastic lymphoma kinase-negative patients. In summary, the failure rate for incompletely resected stage I disease was similar to that for patients with stage II and stage III/IV disease. Whether anaplastic lymphoma kinase negativity contributed to this moderate outcome has to be proven prospectively. This study was registered at www.clinicaltrials.gov as NCT00006455.     

Importance of allogeneic T-cells for disease control after stem cell transplantation for high-risk Langerhans cell histiocytosis

Reduced intensity conditioning followed by allogeneic SCT (RIC-SCT) has recently emerged as promising new salvage option for children suffering from Langerhans cell histiocytosis (LCH) with risk organ involvement and failure to conventional therapy. We report on the posttransplant course of female toddler with high-risk LCH, who achieved complete remission after RIC-SCT, despite a posttransplant chimerism constellation, in which only the T-cell subset proved to be of donor origin in the long-term. We therefore suggest that allogeneic T-cells have played a crucial role in controlling disease activity in this patient and may exert the major curative effect after RIC-SCT for LCH.     

Expression of the putatively regulatory T-cell marker FOXP3 by CD4(+)CD25+ T cells after pediatric hematopoietic stem cell transplantation

FOXP3 has been proposed to be critical for the regulatory function of CD4(+)CD25+ T cells and it has been reported that its expression correlates with protection from graft-versus-host-disease (GvHD) after allogeneic hematopoietic stem cell transplantation (HSCT). Here, by monitoring 28 pediatric HSCT recipients, we found that the levels of FOXP3-mRNA expression in highly enriched CD4(+)CD25+ cells were identical to those in healthy controls irrespective of GvHD status. Moreover, FOXP3-mRNA was abundant in recently in vitro stimulated CD4(+)CD25+ cells that lacked regulatory function. Together these findings suggest that FOXP3-mRNA expression primarily reflects CD4(+)CD25+ cell frequency rather than defining the regulatory potential of CD4(+)CD25+ T cells and GvHD risk after HSCT.