[Myelodysplastic syndrome, acute leukemia and stem cell transplantation]

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematopoietic stem cell disorders. They are characterized by inefficient hematopoiesis leading to peripheral cytopenia of one or more lineages and a variable risk of transformation into acute myeloid leukemia. They may either arise de novo as well as following exposition to environmental toxins, previous radiotherapy or chemotherapy or in the context of autoinflammatory diseases and related therapy. Characteristic cytogenetic abnormalities, along with the numbers of hematopoietic lineages affected and bone marrow blasts, enable an assessment of the risk of leukemic transformation. Acute leukemias are characterized by an accumulation of immature myeloid or lymphatic progenitor cells with limited differentiation capacity in the bone marrow. Proliferation of blast cells leads to suppression of normal hematopoiesis resulting in peripheral pancytopenia or leukocytosis associated with anemia and thrombocytopenia. Acute leukemias following MDS are defined as high-risk diseases. Intensive induction therapy followed by allogeneic stem cell transplantation is currently regarded as the only potentially curative treatment strategy. In this article the basic aspects of current diagnostics and treatment strategies for MDS and acute leukemia are outlined. Because of similarities with rheumatic inflammatory diseases, manifestations and treatment of graft versus host disease (GvHD) are also included.