White Blood Cell Disorders and Platelets:: 5. Miscellaneous Granulocytic Cells

Basophils

  • A basophil and a small lymphocyte are compared in the same field of the upper photograph, A single basophil is shown in the lower photograph.
  • The cytoplasmic granules of the basophil are larger than the granules of toxic granulation.They contain chemical mediators of immediate hypersensitivity, and are found in the cytoplasm and overlying the nucleus (better seen in the lower photograph).
  • Basophilic granules stain metachromatically with toluidine blue indicating the presence of acid mucopolysaccharide or proteoglycans, both thought to be heparin or heparin-like substances.
  • Basophils are related to tissue mast cells, each involved in hypersensitivity responses and following anaphylactic episodes.
  • Under the stimulation of complement components C3a and C5a, many mediators are released from the basophil granules, including histamine, heparin, and eosinophil chemotactic factors of anaphylaxis, or ECF-A.
  • Basophils are the least common neutrophils in the peripheral blood, comprising 2% or less of the differential count.
  • The presence of large granules of irregular size in basophils and the admixture of eosinophilic granules may indicate dysplastic changes associated with myelodysplastic disorders and leukemia.

Earn ASCLS P.A.C.E.® credits for your state clinical laboratory personnel license. Visit LabCE.com for medical laboratory technologist continuing education.

White Cell and Platelet Disorders: Peripheral Blood Clues to Nonneoplastic Conditions course details »

Learn more about medical technologist continuing education for MTs, MLTs, and other lab personnel »

Get information on laboratory safety training for clinical and medical laboratories »