title: Atypical clonal T-cell proliferation in infectious mononucleosis.
abstract: An atypical case of infectious mononucleosis characterized by fever, acute tonsillitis, and bilateral cervical adenopathy is reported in a previously healthy young man. Although serology was positive for the Epstein-Barr virus, the patient did not display peripheral blood lymphocytosis or atypical, reactive lymphocytes. The patient's tonsilar tissue revealed an expanded T-zone of diffuse, monomorphous lymphocytes suggestive of lymphoma. Immunophenotypic analysis of the tonsilar tissue demonstrated more than 90% expression of pan-T markers, while pan-B markers were positive in 5-10% of the interfollicular T-zone cells and in 90% of germinal centre cells. In situ hybridization with a probe specific for EBER1 demonstrated positive staining in approximately 1% of the interfollicular tonsilar lymphocytes. Finally, Southern blot analysis of tonsilar tissue demonstrated a clonal rearrangement of the T-cell receptor gene. The patient recovered from his infection and remains in good health years after presenting with his illness. This case illustrates that T-cell clonality must be evaluated with caution in the setting of a viral infection and can occur in association with benign, self-limited infectious mononucleosis.
authors.affiliation: Department of Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10467, USA.
authors.forename: U R
authors.initials: UR
authors.lastname: Malik
authors.forename: L
authors.initials: L
authors.lastname: Oleksowicz
authors.forename: J P
authors.initials: JP
authors.lastname: Dutcher
authors.forename: H
authors.initials: H
authors.lastname: Ratech
authors.forename: M J
authors.initials: MJ
authors.lastname: Borowitz
authors.forename: P H
authors.initials: PH
authors.lastname: Wiernik
mesh_terms: D000328:Adult; D015139:Blotting, Southern; D003937:Diagnosis, Differential; D015329:Gene Rearrangement, T-Lymphocyte / Q000235:genetics; D004854:Herpesvirus 4, Human / Q000302:isolation & purification; D006801:Humans; D007244:Infectious Mononucleosis / Q000175:diagnosis / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D008232:Lymphoproliferative Disorders / Q000235:genetics / Q000473:pathology / Q000821:virology; D008297:Male; D009693:Nucleic Acid Hybridization; D014066:Palatine Tonsil / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology*