Main Page | See live article | Alphabetical index A lymphocytosis is an increase in the number of lymphocytes in the blood. This is common in acute viral infections, including glandular fever. It may also be seen with intracellular bacterial infections, such as in tuberculosis. The malignant blood disease chronic lymphocytic leukaemia can cause a massive lymphocytosis, as can other leukaemias. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.