Electron Microscopic Study of Leukocytes in Infectious Motionucleosis

I N THIS study the circulating leukocytes, especially the atypical lympho-cytes, of patients with infectious mononucleosis were examined with the electron microscope with emphasis on morphologic deviations from the nor-mal and on the presence or absence of inclusions which might he suggestive of an infectious agent. An attempt was made to determine whether any cells could definitely he labeled atypical on the basis of their appearance in the electron micrographs, and whether they belonged to the lymphocytic or mono-cytic series. The possibility of correlating lymphocytes in electron micrographs with the several Downey types of atypical lymphocytes ’ in Wright stained smears was considered. Differences of opinion exist concerning the criteria for labeling a cell an atypical lymphocyte. Some investigators2’3 regar(l these cells as atypical mcno-cytes. Most workers regard! them as belonging to the lymphocytic series.4 The most extensive description is that by Downey. who placed! the atypical lympho-cytes in three categories according to their appearance in \Vright stained bloo