1 Department of Pediatrics, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06511
Lymphocytosis has long been associated with several disease entities. In children, Pertusis, infectious mononucleosis, and leukemia are examples. More recently, certain adenovirus infections have been implicated. In view of the normal preponderance of lymphocytes over granulocytes during the first few years of life, lymphocytosis in young children must be interpreted with caution.
Over 25 years ago, Carl H. Smith1 described a syndrome which he called acute infectious lymphocytosis. The majority these patients have been without signs or symptoms of illness, an important feature of the disorder. Institutional outbreaks have supported the infectious nature of the disorder. Leukocytosis has been extreme, occasionally in excess of 100,000 white cells per milliliter.