title: Hand-mirror lymphocytes in infectious mononucleosis.
abstract: The identification of a morphologically unique lymphocyte in the peripheral blood of patients with infectious mononucleosis (IM) led to additional studies. Examination of Wright-stained smears of EDTA anticoagulated blood obtained from 25 patients with IM at presentation revealed significantly increased (p less than 0.0001) percentages of hand-mirror lymphocytes (HML) (mean 9.2%) compared with normal controls (mean 2.7%) or controls with nonspecific viral syndromes (mean 2.2%). Follow-up blood samples obtained on 10 of these patients demonstrated a marked increase in the HML count (mean 12.1%) that coincided with the onset of recovery. E-rosette separation of Ficoll-Hypaque-derived peripheral blood lymphocytes from 5 patients with early recovery IM showed the HML to be present almost exclusively in the T-cell population, representing about 25% of the T cells. Identical procedures on 5 controls showed less than 5% HML in the T-cell sample. Cytochemistries supported a T-cell derivation for HML. Electron microscopic examination of HML in IM demonstrated that these cells have unique ultrastructural features that may be related to functions of cellular attachment and cytotoxicity.
mesh_terms: D006801:Humans; D007244:Infectious Mononucleosis / Q000097:blood*; D007958:Leukocyte Count; D008214:Lymphocytes / Q000201:enzymology / Q000473:pathology* / Q000648:ultrastructure; D012397:Rosette Formation; D013997:Time Factors