Benign disorders of white cells I: granulocytes, monocytes, macrophages


The common benign disorders of white cells arise as a response to a systemic process, e.g. infection, inflammation or malignancy.




Granulocytes and monocytes


An increased number of neutrophils in peripheral blood (neutrophil leucocytosis or neutrophilia) is most commonly due to bacterial infection or other causes of inflammation (Box 18.1).






Box 18.1 Causes of neutrophilia (neutrophils >7.5 × 109/L)


Reactive


  • Bacterial infections
  • Inflammation, e.g. collagen diseases, Crohn’s disease
  • Trauma and/or surgery
  • Tissue necrosis/infarction
  • Neoplasia
  • Haemorrhage and haemolysis
  • Metabolic, e.g. diabetic ketoacidosis
  • Pregnancy


Malignant


  • Myeloproliferative disorders
  • Myeloid leukaemias


Drugs


  • Steroids
  • Granulocyte colony-stimulating factor (GCSF)




In bacterial infection, neutrophil granules may stain intensely (toxic granulation) and Döhle bodies (cytoplasmic RNA) may be present. Corticosteroid therapy is also a common cause of neutrophilia. A leukaemoid reaction is a profound reactive neutrophilia in which granulocyte precursors (e.g. myelocytes) appear in the blood.


Neutropenia (reduced number of circulating neutrophils; Box 18.2) is usually due to decreased marrow production. Neutropenia can occur rarely in overwhelming bacterial infection, e.g. septicaemia, bacterial endocarditis. It increases susceptibility to infection, particularly bacterial. Viral infections are a common cause of neutropenia. Chemotherapy or radiotherapy are other frequent causes of neutropenia, which may be severe and life-threatening. The normal neutrophil count is lower in Afro-Caribbean and Middle Eastern subjects than in white people; this has no clinical consequences.





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Jun 12, 2016 | Posted by in HEMATOLOGY | Comments Off on Benign disorders of white cells I: granulocytes, monocytes, macrophages

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