THE RECOGNITION of acute infectious lymphocytosis as an entity separate from infectious mononucleosis dates from Smith's1 report in 1941. Since that time the number of reported cases of this condition has increased, until at this writing 38 have been published. The series of Reyersbach and Lenert2 undoubtedly must be of this nature, and Smith, in his recognition of the entity, made reference to the report of these investigators.
Smith designated infectious lymphocytosis as being acute or chronic and established definite criteria for the diagnosis as differentiated from lymphatic leukemia and infectious mononucleosis.
The disease is termed infectious because it has occurred in small epidemics.3 Recently, Lorenz, Hardy and Alt4 reported the disease in 2 brothers.
Most reports have been of young children under the age of 6 years, although Duncan5 and Yuskis6 recorded cases of the condition in young adults. The symptoms are remarkably