Odczyny białaczkowe

The term leukemoid reaction is used to describe leukocytosis defined as white blood count exceeding 30,000/mm3 with a disorganized increase of precursors such as myelocytes and metamyelocytes in peripheral blood smear. Leukocytosis with “left shift”, may be caused by an increase in neutrophil (granolocytosis) and lymphocyte counts (lymphocytosis). Leukemoid reactions must be distinguished from leuko/erythroblastic reactions characterized by the presence of immature white blood cells and nucleated red cells in the peripheral blood. There are several mechanisms inducing leukemoid reactions - the most common is enhanced production of leucocytes and their increased output from the storage pool in the BM. Leukocytosis is mediated by multiple molecular growth factors (e.g. granulocyte colony stimulating factor, granulocyte-monocyte colony stimulating factor), adhesion molecules (CD11b/CD 18) and cytokines (IL-1, IL-3, IL-6, tumor necrosis factor). Disorders associated with leukemoid reactions are bacterial infections, if granulocytosis occurs, or bacterial and viral infections when lymhocytosis is present. Leukemoid reactions must be differentiated from acute and chronic leukaemias by the absence of other cell line depression, evidence of infection, and absence of blasts in the bone marrow, as well as lack of organomegaly. Leukocytosis may also be recognized in some physiological conditions as a response to stress, physical exercise, during pregnancy, and in newborns.