Leukemoid reaction

Profound leukocytosis > 50

characterized by a significant increase in early neutrophil precursors in the peripheral blood

it is the response of normal bone marrow to cytokine release by lymphocytes, macrophages and other cells in response to infection or trauma

marked "left shift", increased numbers of band forms and sometimes even myelocytes and metamyelocytes in peripheral film.

Proliferation of all NORMAL myeloid elements is observed in bone marrow, whereas immature elements predominate in acute leukemia

low or absent CD 16 --> reduce expresion of Fc receptors --> cannot function as well as mature ones

high Leukocyte alkaline phosphatase (whereas Leukemia has low LAP)



Cytogenetic abnormalities in hematologic malignancy