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Monthly Cell Challenge #1 / 2024

 

Child with reactive and necrotic lymphocytes on peripheral blood film

 

Cells from Monthly Cell Challenge 1

 

Description:

4-year-old girl with fever, stuffy nose, inflamed tonsils with white spots, and swollen lymph nodes was seen by her pediatrician. A Monospot test was negative.

Blood was sent for CBC:

Test Result Units
WBC 4.5     x109/L
HGB 13.3  g/dL
MCV 82 fL
PLT 185 x109/L

Atypical Lympho? flag triggered blood smear analysis on Cellavision DC-1

WBC Differential % x109/L
Neutrophils 30     1.35
Lymphocytes 40 1.8
Variant (Reactive) Lymphocytes 26 1.17
Monocytes 3 0.14
Eosinophils 1 0.05

Reactive lymphocyte:

Monthly cell challenge 1 - Reactive lymphocyte

Some of the lymphocytes appeared apoptotic (necrotic/degenerated) with cytoplasmic vacuolation:

Monthly cell challenge 1 - lymphocyte

 

Diagnosis

Infectious mononucleosis (IM)

Despite a negative monospot test, the pediatrician remained suspicious of infectious mononucleosis (IM). As a result, Epstein Barr Virus (EBV) testing was performed. The results were positive, confirming a diagnosis of IM.
 
IM is caused by acute infection with EBV. The Monospot heterophile test is falsely negative in 40% of children (< 5y) with IM.1 As a result The CDC does not recommend general use of the monospot test.2 EBV antigen and antibody testing has better sensitivity/specificity and should be done in heterophile negative patients with a high degree of clinical suspicion – as in this case.
 
Apoptotic lymphocytes can be found in blood films of up to 90% of IM cases.3 In this patient, both apoptotic and reactive lymphocytes were clearly visible with Cellavision which provided additional clues in the diagnostic workup of IM.

 

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1. Marionneaux SM. Nonmalignant leukocyte dirorders. In: Keohane EM, ed. Rodak's Hematology. 7th ed. Elsevier; 2024:chap 26.

2. CDC. Laboratory Testing for Epstein-Barr Virus (EBV). Centers for Disease Control and Prevention. August 27, 2024. Accessed August 27, 2024. https://www.cdc.gov/epstein-barr/php/laboratories/index.html

3. Fisher MS, Jr., Guerra CG, Hickman JR, et al. Peripheral blood lymphocyte apoptosis: a clue to the diagnosis of acute infectious mononucleosis. Archives of pathology & laboratory medicine. Oct 1996;120(10):951-5.