MLAB 1315 Hematology Keri BrophyMartinez

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MLAB 1315- HematologyKeri Brophy-Martinez

• Unit 19 Reactive Lymphocytosis and Infectious
  Mononucleosis

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Lymphocytosis

• Excess of lymphocytes in the blood.
• Absolute lymphocyte count (ALC) gt 4.0 x 109 /L
  in adults.

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Lymphocytosis

• Reactive lymphocyte - transformed or benign lymph
• Familiar terms are immunocytes, transformed
  lymph, immunoblast, plasmacytoid, Downey cell
• Size varies
• NC ratio varies
• May contain nucleoli
• May contain azurophilic granules

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Lymphocytosis

• Atypical lymphocyte - malignant-appearing lymph
• Seen in leukemias, lymphomas

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Causes of Reactive Lymphocytosis

• Infectious mononucleosis
• Typical lymphocyte is historically referred to as
  a Downey cell with irregular cytoplasmic border,
  increased cytoplasm and dark blue edge around the
  periphery of the cytoplasm.
• Diagnosed today by Monospot serology test
• Caused by the Epstein-Barr Virus (EBV) which
  enters the body orally (kissing disease)
• Clinical symptoms
• Sore throat
• Dysphagia
• General malaise
• Fatigue
• Spleen is enlarged and nodes are firm but not
  tender or warm
• Generally seen in children and young adults

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Causes of Reactive Lymphocytosis

• Cytomegalovirus (CMV) Infection
• Belongs to herpes family
• Endemic worldwide
• Acquired through transfusions (must give CMV
  negative blood to potential bone marrow
  transplant recipients).

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Causes of Reactive Lymphocytosis

• Other viruses

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Causes of Reactive Lymphocytosis

• Bacterial infections
• Brucella
• Mycobacterium tuberculosis
• Spirochetes
• Pertussis (whooping cough)

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Malignant conditions

• To be discussed in the leukemias