Sample Question from White Cell and Platelet Disorders: Peripheral Blood Clues to Nonneoplastic Conditions, presented by MediaLab

White Blood Cell Disorders and Platelets:: 1. Leukemoid Reaction vs Toxic Changes

Leukemoid reaction revisited

The term leukemoid reaction is used to describe peripheral white blood cells that on the stained blood smear may have some resemblances to leukemia cells.
Quantatively in a leukemoid reaction, the neutrophil count is >50,000 cumm with more immature cells, particularly myelocytes, than are usually present in toxic left shift syndromes. The presence of immature cells in a leukemoid reaction awakens thoughts of leukemia. Great care must be taken to make a distinct differentiation between aberrant white blood cell proliferations and a benign but exaggerated granulocytic proliferative response.
Our material is from a 1-month-old girl with Down's syndrome. Her total white blood count was 37,000/mm3 interpreted as leukocytosis with left shift.
Leukocytosis with a left shift, and leukemoid reactions with high alkaline phosphatase are conditions to be mindful of in patients with Down's syndrome.
The alkaline phosphatase score is high in leukemoid reactions, low in granulocytic leukemia.

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