Atypical Lymphocytes in Acute Infectious Mononucleosis

Abstract

Atypical lymphocytes from four patients with acute infectious mononucleosis were tested for the presence of five separate markers of thymic-derived (T) and bone-marrow-derived (B) lymphocytes. This test was done to rule out the possibility that the previously described sheep erythrocyte rosetting capacity (a normal T-cell marker) of atypical lymphocytes in infectious mononucleosis was due to passive adsorption or production of heterophil (anti-sheep erythrocyte) antibody on the surface of B lymphocytes and was therefore a false-positive reaction. The vast majority of atypical lymphocytes had sheep erythrocyte receptors as well as human T-lymphocyte specific antigens and lacked three reliable B-cell markers (complement receptors, surface immunoglobulin, and human B lymphocyte specific antigens). Since Epstein-Barr virus, the etiologic agent of infectious mononucleosis, has recently been shown to infect only B lymphocytes, the finding that the atypical lymphocytes are indeed T cells suggests that these uninfected T cells play a part in the immune response to the Epstein-Barr virus. (N Engl J Med 291:1145–1148, 1974)