Peripheral blood lymphocyte apoptosis: a clue to the diagnosis of acute infectious mononucleosis

Arch Pathol Lab Med. 1996 Oct;120(10):951-5.


Objective: To describe the morphology and significance of apoptotic lymphocytes in peripheral blood smears of patients with acute infectious mononucleosis. To our knowledge this has not been previously reported.

Design: Peripheral blood smears from 27 patients with a positive heterophile antibody test were collected and reviewed for the presence of apoptotic lymphocytes. Flow cytometry was performed on three cases to document the previously described low expression of bcl-2 in lymphocytes in infectious mononucleosis. Four control patient populations comprising 80 cases were similarly screened for the presence of apoptotic lymphocytes.

Setting: The specimens were collected over a 3-month period in two laboratories at our tertiary care hospital; all specimens were processed according to a standard protocol.

Patients: Young adult military recruits and their spouses, military dependent adolescents, and retired military personnel.

Results: Twenty-four (88.9%) of 27 peripheral blood smears of patients with acute infectious mononucleosis contained readily identifiable apoptotic lymphocytes. Three (3.75%) of 80 control peripheral blood smears were identified with rare apoptotic lymphocytes, all occurring in patients with viral upper respiratory infections.

Conclusions: The finding of apoptotic lymphocytes in a peripheral blood smear is useful in the differential diagnosis of infectious mononucleosis and neoplastic hematolymphoid processes.

Publication types

  • Case Reports
  • Comparative Study

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Apoptosis*
  • Case-Control Studies
  • Diagnosis, Differential
  • Female
  • Flow Cytometry
  • Hematologic Neoplasms / blood
  • Hematologic Neoplasms / diagnosis
  • Humans
  • Infectious Mononucleosis / blood*
  • Infectious Mononucleosis / diagnosis*
  • Lymphocytes / pathology*
  • Male