(lim'fōsītō'sis)
n
An absolute or relative increase in the normal number of lymphocytes in the circulating blood. Various limits are given; for example, absolute lymphocytosis is said to be present if the total number of cells exceeds 4500/mm3, whereas relative lymphocytosis is said to be present if the percentage of lymphocytes is greater than 45% and the total number of cells is less than 4500/mm3. Lymphocytosis may be associated with infancy, exophthalmic goiter, mumps, rubella, infectious mononucleosis, sunburn, lymphatic leukemia, pertussis, and pyogenic infections in childhood.