The bone marrow has three myeloid cell lines: granulocytic, erythroid, and megakaryocytic. The MDS may affect one or more myeloid cell lines, resulting in anemia, neutropenia, and/or thrombocytopenia.
MDS causes normocytic or macrocytic (non-megaloblastic) anemia. The hemoglobin is typically less than 10 g/dL. The reticulocyte count is normal to low, and patients are usually transfusion-dependent. The anemia in MDS is refractory to any replacement therapy (iron, B12, or folate).
