70 Infectious Mononucleosis/Reactive Lymphocytes
Michelle To and Valentin Villatoro
Images of peripheral blood smears with heterogeneous reactive lymphocytes with prominent basophilic skirting of the cytoplasm. From MLS Collection, University of Alberta.
Image 1: 50x oil immersion. https://doi.org/10.7939/R3G44J57B
Image 2: 50x oil immersion. https://doi.org/10.7939/R34M91R9B
Image 3: 60 x oil immersion. https://doi.org/10.7939/R3GQ6RH6F
Large reactive (atypical) lymphocytes that represent activated T cells. The cytoplasm shows characteristic basophilic skirting in areas where there is contact with red blood cells. Red blood cells look as if they are creating indents in the cytoplasm. The population of reactive lymphocytes is heterogeneous with diverse shapes and sizes in cytoplasm and nuclear shapes.
Epstein-Barr Virus (EBV) infection that is usually acute, benign, and self-limiting.
Age group affected:1,3,5
Young adults (approx. 15-25 years of age)
Common Clinical Symptoms:1,4
Classic Triad: Pharyngitis, fever, lymphadenopathy.
Positive heterophile antibody*
Positive EBV specific antigen and antibody (ELISA)*
Elevated C-reactive protein (CRP)
Flow cytometry (to rule out malignancies with similar cell morphologies)
*Positivity for antigen or antibody varies depending on the date of testing. Some antigen or antibodies may appear only after a few weeks of infection.
CD3, CD4 or CD8
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