Hemophagocytic lymphohistiocytosis (HLH) is a lifethreatening disease characterized by unremittin... more Hemophagocytic lymphohistiocytosis (HLH) is a lifethreatening disease characterized by unremitting fever, hepatosplenomegaly, cytopenias, as well as changes in coagulation and lipids. The symptoms are due to high levels of cytokines secreted by immune effector cells which display functional defects.
Since 1962, desferrioxamine (deferoxamine, DFO) has been utilized for the treatment of secondary ... more Since 1962, desferrioxamine (deferoxamine, DFO) has been utilized for the treatment of secondary hemosiderosis. For about 30 years, DFO therapy has been performed as nightly continuous subcutaneous infusion. About 20 years ago, the first oral iron chelator (deferiprone, DFP) was presented. Concerns about potential side effects were responsible for the late acceptance and license of this drug which is limited to the use as second-line therapy for patients with thalassemia major. During recent years, chelation therapy and its evaluation started to progress rapidly. Clinical research and drug development as well as the introduction of new methods for the assessment of iron overload contributed to these advances. By using cardiac T2 (*) MRI it was possible to examine the specific effect of a chelator on myocardial siderosis. Clinical studies using this method indicated superiority of DFP compared to DFO with respect to the treatment of myocardial siderosis. Several retrospective and first prospective clinical trials seem to confirm this observation. In parallel, treatment strategies based on the combination of DFO and DFP have been developed. Using both drugs simultaneously or sequentially, additive and synergistic effects contribute to the fast elimination of iron from different organs at risk for siderotic damage. Deferasirox (DSX) is a recently developed oral chelator which shows good efficacy and tolerability in patients with transfusional hemosiderosis due to various underlying disorders. Long-term studies will define the future importance of DSX for iron chelation treatment. For the first time, there is a choice between three commercially available chelating agents for patients with transfusional iron overload. This will allow a highly effective, individually tailored treatment hopefully leading to a fundamental improvement of patients' life expectancy and quality.
Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program, 2013
Hemophagocytic lymphohistiocytosis (HLH) is not an independent disease but rather a life-threaten... more Hemophagocytic lymphohistiocytosis (HLH) is not an independent disease but rather a life-threatening clinical syndrome that occurs in many underlying conditions and in all age groups. HLH is the consequence of a severe, uncontrolled hyperinflammatory reaction that in most cases is triggered by an infectious agent. Persistent stimulation of lymphocytes and histiocytes results in hypercytokinemia, leading to the characteristic symptoms of HLH. Genetic defects in familial HLH and in immunodeficiency syndromes associated with albinism affect the transport, processing, and function of cytotoxic granules in natural killer cells and cytotoxic T lymphocytes. This leads to defective killing of target cells and a failure to contract the immune response. The defects are increasingly found also in adolescents and adults. Acquired HLH occurs in autoinflammatory and autoimmune diseases (macrophage activation syndrome) and in patients with iatrogenic immunosuppression or with malignancies, but als...
Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases i... more Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases including the rapidly fatal autosomal recessive disease of familial hemophagocytic lymphohistiocytosis (FHL). The onset is usually during the first years of life with fever, cytopenia, and hepatosplenomegaly. Neurologic symptoms may supervene. Similar symptoms may occur in the infection-(virus-)associated or malignancy-associated hemophagocytic syndromes (IAHS/MAHS). Triggering infections can be found in all these diseases and do not allow for reliable differentiation. An international treatment protocol (HLH-94) has been developed for FHL, but immunomodulatory treatment may be justified in IAHS and MAHS as well, since they also have a high fatality rate.
Rapid intracellular transport and secretion of cytotoxic granules through the immunological synap... more Rapid intracellular transport and secretion of cytotoxic granules through the immunological synapse requires a balanced interaction of several proteins. Disturbance of this highly regulated process underlies familial hemophagocytic lymphohistiocytosis (FHL), a genetically ...
TEL-AML the most common genetic alteration in childhood precursor B acute lymphoblastic leukemia ... more TEL-AML the most common genetic alteration in childhood precursor B acute lymphoblastic leukemia (BCP-ALL) is associated with a favorable prognosis. We studied the expression of nerve growth factor/tumor necrosis factor receptor (NGFR/TNFR)/ligand family members on 108 primary BCP-ALL samples by flow cytometry and compared both their baseline expression and CD40-induced modulation on TEL-AML positive and negative leukemia samples. Our findings demonstrate that TEL-AML positive patients exhibit a significantly higher percentage of CD40, CD27 and p75NTR positive blasts at diagnosis. This might well contribute to the improved relapse-free survival of these patients assessed in Kaplan Meier analysis as CD27 and p75NTR directly mediate apoptotic signals. Furthermore CD40 ligation enhances antigen presenting and T cell stimulatory capacity via significant up regulation of CD70 while adequate response to physiological maturation signals as indicated by concomitant down regulation of CD27 is retained in TEL-AML positive leukemia. These data provide novel insights in immunological control mechanisms preserved in this leukemia subtype and suggest that not only treatment with chemicals such as HDAC inhibitors but also retained in vivo response to CD40 ligation contributes to improved immune surveillance in these patients which may add to a superior relapse-free survival observed particularly in the presence of other risk factors.
Skeletal involvement is generally, but not universally, characteristic of Langerhans cell histioc... more Skeletal involvement is generally, but not universally, characteristic of Langerhans cell histiocytosis (LCH). We investigated whether the presence of bone lesions at diagnosis is a prognostic factor for survival in LCH. Nine hundred and thirty-eight children with multisystem (MS) LCH, both high (386 RO+) and low (ROÀ) risk, were evaluated for bone lesions at diagnosis. Risk organ (RO+) involvement was defined as: haematopoietic system (haemoglobin <100 g/l, and/or white blood cell count <4Á0 9 10 9 /l and/or platelet count <100 9 10 9 /l), spleen (>2 cm below the costal margin), liver (>3 cm and/or hypoproteinaemia, hypoalbuminaemia, hyperbilirubinaemia, and/or increased aspartate transaminase/alanine transaminase). Given the general view that prognosis in LCH worsens with increasing extent of disease, the surprising finding was that in MS+RO+ LCH the probability of survival with bone involvement 74 AE 3% (n = 230, 56 events) was reduced to 62 AE 4% (n = 156, 55 events) if this was absent (P = 0Á007). An even greater difference was seen in the subgroup of patients with both liver and either haematopoiesis or spleen involvement: 61 AE 5% survival (n = 105; 52 events) if patients had bony lesions, versus 47 AE 5% (n = 111; 39 events) if they did not (P = 0Á014). This difference was retained in multivariate analysis (P = 0Á048). Although as yet unexplained, we conclude that bone involvement at diagnosis is a previously unrecognized favourable prognostic factor in MS+RO+ LCH.
Hematology-oncology Clinics of North America, 1998
Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases i... more Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases in which a T-cell induced, uncontrolled activation of phagocytosing macrophages may lead to fever, organomegaly, and pancytopenia. The underlying immunologic disturbance can either be genetically transmitted, like in FHL, or acquired, as in IAHS or MAHS. Triggering infections can be found in all these diseases and do not allow a reliable differentiation. An international treatment protocol has been developed for FHL. IAHS and MAHS also have a high fatality rate, justifying immunomodulatory treatment if the disease is progressive.
Hematology-oncology Clinics of North America - HEMATOL ONCOL CLIN N AMER, 1998
Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases i... more Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases including the rapidly fatal autosomal recessive disease of familial hemophagocytic lymphohistiocytosis (FHL). The onset is usually during the first years of life with fever, cytopenia, and hepatosplenomegaly. Neurologic symptoms may supervene. Similar symptoms may occur in the infection-(virus-)associated or malignancy-associated hemophagocytic syndromes (IAHS/MAHS). Triggering infections can be found in all these diseases and do not allow for reliable differentiation. An international treatment protocol (HLH-94) has been developed for FHL, but immunomodulatory treatment may be justified in IAHS and MAHS as well, since they also have a high fatality rate.
A rare case of primary intestinal T-cell lymphoma (ITL) of an 8-year-old boy is reported. Medium-... more A rare case of primary intestinal T-cell lymphoma (ITL) of an 8-year-old boy is reported. Medium- to large-sized tumor cells were betaF1+, CD3+, CD8+. TIA-1+, but CD4-, CD5-, CD30-, CD56-, CD20-, CD79a-, TdT-, consistent with an intraepithelial lymphocyte (IEL) origin. They showed monoclonal rearrangement of the T-cell receptor gamma-chain and no evidence of EBV infection. No clinical, histologic, laboratory, or genetic evidence of celiac disease was detected. In adults, ITL is often associated with enteropathy and has a very poor outcome. Our patient remains in first remission 30 months after finishing the acute lymphoblastic leukemia protocol COALL-07-03 high risk standard.
Pathologists and pediatric hematologist/ oncologists of the World Health Organization&amp;amp... more Pathologists and pediatric hematologist/ oncologists of the World Health Organization&amp;amp;#39;s Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.
The prognosis of infant ALL, characterized by a high incidence of the immature CD10 negative B-li... more The prognosis of infant ALL, characterized by a high incidence of the immature CD10 negative B-lineage ALL (proB ALL) is poor. This study aimed to determine the resistance profile of infant ALL cells. In vitro drug resistance was determined by the MTT assay of 395 children with ALL at initial diagnosis: there were 21 infants Ͻ Ͻ Ͻ1.5 years of which nine Ͻ Ͻ Ͻ1 year, 284 children aged 1.5-10 years (intermediate age group) and 90 children Ͼ Ͼ Ͼ10 years. Immunophenotyping resulted in 310 cALL/preB ALL, 69 T-ALL, 15 proB ALL and one unknown cases. The following drugs were tested: daunorubicin, doxorubicin, mitoxantrone, idarubicin (Ida), prednisolone (Pred), dexamethasone (DXM), vincristine (VCR), Asparaginase (Asp), 6-MP, 6-TG, AraC, VM26 and 4-HOO-ifosfamide (Ifos). Infants Ͻ Ͻ Ͻ1.5 years were significantly more resistant to Pred (Ͼ Ͼ Ͼ500-fold), Asp (11fold) and VM26 (2.7-fold) but significantly more sensitive to Ara-C (2.3-fold) compared to the intermediate age group. When analyzing infants Ͻ Ͻ Ͻ1 year of age similar results were found. ProB ALL cells (seven infants Ͻ Ͻ Ͻ1.5 years; eight children Ͼ Ͼ Ͼ1.5 years) were significantly more resistant to glucocorticoids, Asp, thiopurines, anthracyclines and Ifos compared to cALL/preB ALL but more sensitive to Ara-C. Cells from children Ͼ Ͼ Ͼ10 years were significantly more resistant to Pred, DXM, Asp, Ida and 6-MP. T-ALL cells showed a strong resistance to Pred, Asp and VCR and a mild but significant resistance to all other drugs except thiopurines and VM26. We conclude that the poor prognosis of infant ALL is associated with a resistance to glucocorticoids and Asp. However, ALL cells from infants show a relatively high sensitivity to Ara-C which suggests that infants with ALL might benefit from treatment schedules that incorporate more Ara-C than the current treatment protocols.
Clinical heterogeneity within t(12;21) or TEL/AML1-positive ALL (25% of childhood common/preB ALL... more Clinical heterogeneity within t(12;21) or TEL/AML1-positive ALL (25% of childhood common/preB ALL) indicates that additional genetic changes might contribute to outcome. We studied the relation between additional genetic changes in TEL(ETV6) and AML1(RUNX1) (FISH), drug sensitivity (MTT assay) and clinical outcome in 143 DCOG and COALL-treated t(12;21)-positive ALL patients. Additional genetic changes in TEL and AML1 were present in 83% of the patients, and consisted of (partial) deletion of the second TEL gene (70%), an extra AML1 gene (23%) or an extra der(21)t(12;21) (10%). More than one additional change was observed in 20%. Disease-free survival (pDFS) of DCOG patients without additional genetic changes (4 years pDFS7s.e. 53717%) and of those with an extra der(21)t(12;21) (60722%) is poorer than that of compared to patients with other additional genetic changes in TEL or AML1 (7976%; P-trend ¼ 0.02). This was mainly due to the occurrence of early relapses within 2.5 years after the first diagnosis. Similar observations were found in the COALL cohort, albeit not significant owing to limited follow-up. Multivariate analysis including age, WBC and genetic abnormalities in TEL and/or AML1 showed that especially, in vitro resistance to prednisolone (hazard ratio 5.78, 95% CI 1.45-23.0; P ¼ 0.01) is an independent prognostic factor in DCOG-and COALL-treated t(12;21)-positive ALL.
Hemophagocytic lymphohistiocytosis (HLH) is a lifethreatening disease characterized by unremittin... more Hemophagocytic lymphohistiocytosis (HLH) is a lifethreatening disease characterized by unremitting fever, hepatosplenomegaly, cytopenias, as well as changes in coagulation and lipids. The symptoms are due to high levels of cytokines secreted by immune effector cells which display functional defects.
Since 1962, desferrioxamine (deferoxamine, DFO) has been utilized for the treatment of secondary ... more Since 1962, desferrioxamine (deferoxamine, DFO) has been utilized for the treatment of secondary hemosiderosis. For about 30 years, DFO therapy has been performed as nightly continuous subcutaneous infusion. About 20 years ago, the first oral iron chelator (deferiprone, DFP) was presented. Concerns about potential side effects were responsible for the late acceptance and license of this drug which is limited to the use as second-line therapy for patients with thalassemia major. During recent years, chelation therapy and its evaluation started to progress rapidly. Clinical research and drug development as well as the introduction of new methods for the assessment of iron overload contributed to these advances. By using cardiac T2 (*) MRI it was possible to examine the specific effect of a chelator on myocardial siderosis. Clinical studies using this method indicated superiority of DFP compared to DFO with respect to the treatment of myocardial siderosis. Several retrospective and first prospective clinical trials seem to confirm this observation. In parallel, treatment strategies based on the combination of DFO and DFP have been developed. Using both drugs simultaneously or sequentially, additive and synergistic effects contribute to the fast elimination of iron from different organs at risk for siderotic damage. Deferasirox (DSX) is a recently developed oral chelator which shows good efficacy and tolerability in patients with transfusional hemosiderosis due to various underlying disorders. Long-term studies will define the future importance of DSX for iron chelation treatment. For the first time, there is a choice between three commercially available chelating agents for patients with transfusional iron overload. This will allow a highly effective, individually tailored treatment hopefully leading to a fundamental improvement of patients&#39; life expectancy and quality.
Hematology / the Education Program of the American Society of Hematology. American Society of Hematology. Education Program, 2013
Hemophagocytic lymphohistiocytosis (HLH) is not an independent disease but rather a life-threaten... more Hemophagocytic lymphohistiocytosis (HLH) is not an independent disease but rather a life-threatening clinical syndrome that occurs in many underlying conditions and in all age groups. HLH is the consequence of a severe, uncontrolled hyperinflammatory reaction that in most cases is triggered by an infectious agent. Persistent stimulation of lymphocytes and histiocytes results in hypercytokinemia, leading to the characteristic symptoms of HLH. Genetic defects in familial HLH and in immunodeficiency syndromes associated with albinism affect the transport, processing, and function of cytotoxic granules in natural killer cells and cytotoxic T lymphocytes. This leads to defective killing of target cells and a failure to contract the immune response. The defects are increasingly found also in adolescents and adults. Acquired HLH occurs in autoinflammatory and autoimmune diseases (macrophage activation syndrome) and in patients with iatrogenic immunosuppression or with malignancies, but als...
Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases i... more Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases including the rapidly fatal autosomal recessive disease of familial hemophagocytic lymphohistiocytosis (FHL). The onset is usually during the first years of life with fever, cytopenia, and hepatosplenomegaly. Neurologic symptoms may supervene. Similar symptoms may occur in the infection-(virus-)associated or malignancy-associated hemophagocytic syndromes (IAHS/MAHS). Triggering infections can be found in all these diseases and do not allow for reliable differentiation. An international treatment protocol (HLH-94) has been developed for FHL, but immunomodulatory treatment may be justified in IAHS and MAHS as well, since they also have a high fatality rate.
Rapid intracellular transport and secretion of cytotoxic granules through the immunological synap... more Rapid intracellular transport and secretion of cytotoxic granules through the immunological synapse requires a balanced interaction of several proteins. Disturbance of this highly regulated process underlies familial hemophagocytic lymphohistiocytosis (FHL), a genetically ...
TEL-AML the most common genetic alteration in childhood precursor B acute lymphoblastic leukemia ... more TEL-AML the most common genetic alteration in childhood precursor B acute lymphoblastic leukemia (BCP-ALL) is associated with a favorable prognosis. We studied the expression of nerve growth factor/tumor necrosis factor receptor (NGFR/TNFR)/ligand family members on 108 primary BCP-ALL samples by flow cytometry and compared both their baseline expression and CD40-induced modulation on TEL-AML positive and negative leukemia samples. Our findings demonstrate that TEL-AML positive patients exhibit a significantly higher percentage of CD40, CD27 and p75NTR positive blasts at diagnosis. This might well contribute to the improved relapse-free survival of these patients assessed in Kaplan Meier analysis as CD27 and p75NTR directly mediate apoptotic signals. Furthermore CD40 ligation enhances antigen presenting and T cell stimulatory capacity via significant up regulation of CD70 while adequate response to physiological maturation signals as indicated by concomitant down regulation of CD27 is retained in TEL-AML positive leukemia. These data provide novel insights in immunological control mechanisms preserved in this leukemia subtype and suggest that not only treatment with chemicals such as HDAC inhibitors but also retained in vivo response to CD40 ligation contributes to improved immune surveillance in these patients which may add to a superior relapse-free survival observed particularly in the presence of other risk factors.
Skeletal involvement is generally, but not universally, characteristic of Langerhans cell histioc... more Skeletal involvement is generally, but not universally, characteristic of Langerhans cell histiocytosis (LCH). We investigated whether the presence of bone lesions at diagnosis is a prognostic factor for survival in LCH. Nine hundred and thirty-eight children with multisystem (MS) LCH, both high (386 RO+) and low (ROÀ) risk, were evaluated for bone lesions at diagnosis. Risk organ (RO+) involvement was defined as: haematopoietic system (haemoglobin <100 g/l, and/or white blood cell count <4Á0 9 10 9 /l and/or platelet count <100 9 10 9 /l), spleen (>2 cm below the costal margin), liver (>3 cm and/or hypoproteinaemia, hypoalbuminaemia, hyperbilirubinaemia, and/or increased aspartate transaminase/alanine transaminase). Given the general view that prognosis in LCH worsens with increasing extent of disease, the surprising finding was that in MS+RO+ LCH the probability of survival with bone involvement 74 AE 3% (n = 230, 56 events) was reduced to 62 AE 4% (n = 156, 55 events) if this was absent (P = 0Á007). An even greater difference was seen in the subgroup of patients with both liver and either haematopoiesis or spleen involvement: 61 AE 5% survival (n = 105; 52 events) if patients had bony lesions, versus 47 AE 5% (n = 111; 39 events) if they did not (P = 0Á014). This difference was retained in multivariate analysis (P = 0Á048). Although as yet unexplained, we conclude that bone involvement at diagnosis is a previously unrecognized favourable prognostic factor in MS+RO+ LCH.
Hematology-oncology Clinics of North America, 1998
Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases i... more Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases in which a T-cell induced, uncontrolled activation of phagocytosing macrophages may lead to fever, organomegaly, and pancytopenia. The underlying immunologic disturbance can either be genetically transmitted, like in FHL, or acquired, as in IAHS or MAHS. Triggering infections can be found in all these diseases and do not allow a reliable differentiation. An international treatment protocol has been developed for FHL. IAHS and MAHS also have a high fatality rate, justifying immunomodulatory treatment if the disease is progressive.
Hematology-oncology Clinics of North America - HEMATOL ONCOL CLIN N AMER, 1998
Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases i... more Hemophagocytic lymphohistiocytosis represents a spectrum of pathogenetically different diseases including the rapidly fatal autosomal recessive disease of familial hemophagocytic lymphohistiocytosis (FHL). The onset is usually during the first years of life with fever, cytopenia, and hepatosplenomegaly. Neurologic symptoms may supervene. Similar symptoms may occur in the infection-(virus-)associated or malignancy-associated hemophagocytic syndromes (IAHS/MAHS). Triggering infections can be found in all these diseases and do not allow for reliable differentiation. An international treatment protocol (HLH-94) has been developed for FHL, but immunomodulatory treatment may be justified in IAHS and MAHS as well, since they also have a high fatality rate.
A rare case of primary intestinal T-cell lymphoma (ITL) of an 8-year-old boy is reported. Medium-... more A rare case of primary intestinal T-cell lymphoma (ITL) of an 8-year-old boy is reported. Medium- to large-sized tumor cells were betaF1+, CD3+, CD8+. TIA-1+, but CD4-, CD5-, CD30-, CD56-, CD20-, CD79a-, TdT-, consistent with an intraepithelial lymphocyte (IEL) origin. They showed monoclonal rearrangement of the T-cell receptor gamma-chain and no evidence of EBV infection. No clinical, histologic, laboratory, or genetic evidence of celiac disease was detected. In adults, ITL is often associated with enteropathy and has a very poor outcome. Our patient remains in first remission 30 months after finishing the acute lymphoblastic leukemia protocol COALL-07-03 high risk standard.
Pathologists and pediatric hematologist/ oncologists of the World Health Organization&amp;amp... more Pathologists and pediatric hematologist/ oncologists of the World Health Organization&amp;amp;#39;s Committee on Histiocytic/Reticulum Cell Proliferations and the Reclassification Working Group of the Histiocyte Society present a classification of the histiocytic disorders that primarily affect children. Nosology, based on the lineage of lesional cells and biological behavior, is related to the ontogeny of histiocytes (macrophages and dendritic cells of the immune system). Dendritic cell-related disorders of varied biological behavior are dominated by Langerhans cell histiocytosis, but separate secondary proliferations of dendritic cells must be differentiated. Juvenile xanthogranuloma represents a disorder of dermal dendrocytes, another dendritic cell of skin. The hemophagocytic syndromes are the most common of the macrophage-related disorders of varied biological behavior. Guidelines for distinguishing the exceedingly rare malignant diseases of histiocytes from large cell lymphomas through the use of a battery of special studies are provided.
The prognosis of infant ALL, characterized by a high incidence of the immature CD10 negative B-li... more The prognosis of infant ALL, characterized by a high incidence of the immature CD10 negative B-lineage ALL (proB ALL) is poor. This study aimed to determine the resistance profile of infant ALL cells. In vitro drug resistance was determined by the MTT assay of 395 children with ALL at initial diagnosis: there were 21 infants Ͻ Ͻ Ͻ1.5 years of which nine Ͻ Ͻ Ͻ1 year, 284 children aged 1.5-10 years (intermediate age group) and 90 children Ͼ Ͼ Ͼ10 years. Immunophenotyping resulted in 310 cALL/preB ALL, 69 T-ALL, 15 proB ALL and one unknown cases. The following drugs were tested: daunorubicin, doxorubicin, mitoxantrone, idarubicin (Ida), prednisolone (Pred), dexamethasone (DXM), vincristine (VCR), Asparaginase (Asp), 6-MP, 6-TG, AraC, VM26 and 4-HOO-ifosfamide (Ifos). Infants Ͻ Ͻ Ͻ1.5 years were significantly more resistant to Pred (Ͼ Ͼ Ͼ500-fold), Asp (11fold) and VM26 (2.7-fold) but significantly more sensitive to Ara-C (2.3-fold) compared to the intermediate age group. When analyzing infants Ͻ Ͻ Ͻ1 year of age similar results were found. ProB ALL cells (seven infants Ͻ Ͻ Ͻ1.5 years; eight children Ͼ Ͼ Ͼ1.5 years) were significantly more resistant to glucocorticoids, Asp, thiopurines, anthracyclines and Ifos compared to cALL/preB ALL but more sensitive to Ara-C. Cells from children Ͼ Ͼ Ͼ10 years were significantly more resistant to Pred, DXM, Asp, Ida and 6-MP. T-ALL cells showed a strong resistance to Pred, Asp and VCR and a mild but significant resistance to all other drugs except thiopurines and VM26. We conclude that the poor prognosis of infant ALL is associated with a resistance to glucocorticoids and Asp. However, ALL cells from infants show a relatively high sensitivity to Ara-C which suggests that infants with ALL might benefit from treatment schedules that incorporate more Ara-C than the current treatment protocols.
Clinical heterogeneity within t(12;21) or TEL/AML1-positive ALL (25% of childhood common/preB ALL... more Clinical heterogeneity within t(12;21) or TEL/AML1-positive ALL (25% of childhood common/preB ALL) indicates that additional genetic changes might contribute to outcome. We studied the relation between additional genetic changes in TEL(ETV6) and AML1(RUNX1) (FISH), drug sensitivity (MTT assay) and clinical outcome in 143 DCOG and COALL-treated t(12;21)-positive ALL patients. Additional genetic changes in TEL and AML1 were present in 83% of the patients, and consisted of (partial) deletion of the second TEL gene (70%), an extra AML1 gene (23%) or an extra der(21)t(12;21) (10%). More than one additional change was observed in 20%. Disease-free survival (pDFS) of DCOG patients without additional genetic changes (4 years pDFS7s.e. 53717%) and of those with an extra der(21)t(12;21) (60722%) is poorer than that of compared to patients with other additional genetic changes in TEL or AML1 (7976%; P-trend ¼ 0.02). This was mainly due to the occurrence of early relapses within 2.5 years after the first diagnosis. Similar observations were found in the COALL cohort, albeit not significant owing to limited follow-up. Multivariate analysis including age, WBC and genetic abnormalities in TEL and/or AML1 showed that especially, in vitro resistance to prednisolone (hazard ratio 5.78, 95% CI 1.45-23.0; P ¼ 0.01) is an independent prognostic factor in DCOG-and COALL-treated t(12;21)-positive ALL.
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