Interleukin-2 and gene therapy in the management of acute lymphoblastic leukaemia

Molecular pathway activation features of pediatric acute myeloid leukemia (AML) and acute lymphoblast leukemia (ALL) cells

Acute lymphoblast leukemia (ALL) is characterized by overproduction of immature white blood cells in the bone marrow. ALL is most common in the childhood and has high (>80%) cure rate. In contrast, acute myeloid leukemia (AML) has far greater mortality rate than the ALL and is most commonly affecting older adults. However, AML is a leading cause of childhood cancer mortality. In this study, we compare gene expression and molecular pathway activation patterns in three normal blood, seven pediatric ALL and seven pediatric AML bone marrow samples. We identified 172/94 and 148/31 characteristic gene expression/pathway activation signatures, clearly distinguishing pediatric ALL and AML cells, respectively, from the normal blood. The pediatric AML and ALL cells differed by 139/34 gene expression/pathway activation biomarkers. For the adult 30 AML and 17 normal blood samples, we found 132/33 gene expression/pathway AML-specific features, of which only 7/2 were common for the adult and pediatric AML and, therefore, age-independent. At the pathway level, we found more differences than similarities between the adult and pediatric forms. These findings suggest that the adult and pediatric AMLs may require different treatment strategies.

T cells remaining after intensive chemotherapy for acute myelogenous leukemia show a broad cytokine release profile including high levels of interferon-gamma that can be further increased by a novel protein kinase C agonist PEP005

Cytokines are released during T cell activation, including the potentially anti-leukemic interferon-gamma (IFNgamma), but also the hematopoietic growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF) that enhance proliferation and inhibit apoptosis of acute myelogenous leukemia (AML) cells. In the present study we investigated the release of IFNgamma and GM-CSF by circulating T cells in AML patients with chemotherapy-induced cytopenia. T cells were activated with anti-CD3 plus anti-CD28 in a whole-blood assay in the presence of their natural cytokine network. We examined 63 samples derived from 16 AML patients during 28 chemotherapy cycles. Activated T cells showed a broad cytokine release profile, but IFNgamma and GM-CSF levels showed a significant correlation and were generally higher than the other cytokine levels. Higher IFNgamma and GM-CSF responses were associated with a low CD4:CD8 ratio, older patient age and no ongoing chemotherapy indicating potential utility of T cell activation regimes for the older AML patient. The cytokine levels could be further increased by the novel protein kinase C agonist PEP005, which also induced significant production of IL2 and TNFalpha which could contribute to anti-tumor effects in AML patients. We conclude that remaining T cells after intensive AML therapy show a broad cytokine release profile including high and significantly correlated levels of potentially anti-leukemic IFNgamma and the AML growth factor GM-CSF. The final outcome of an AML-initiated T cell cytokine response will thus depend on the functional characteristics of the AML cells, in particular the relative expression of IFNgamma and GM-CSF receptors which differs between AML patients.