A high percentage of lymphocytes as shown on a complete blood count can indicate chronic bacterial infection, infectious hepatitis, infectious mononucleosis, lymphocytic leukemia, multiple myeloma, or a viral infection from diseases such as mumps or measles, according to MedlinePlus. A normal range for lymphocytes is 20 to 40 percent. An abnormal increase of a particular white blood cell can cause a decrease in others.
Lymphocytopenia, or lymphopenia, is a disorder caused by a shortage of lymphocytes, which are cells generated in bone marrow that help protect the body from infection. Lymphocytes include three types of infection fighters: B lymphocytes, T lymphocytes and natural killer cells. Lymphocytopenia is usually characterized by a low number of T lymphocytes. Certain factors can lead to a low lymphocyte count, including the body's inability to make enough lymphocytes or the destruction of lymphocytes; lymphocytes being trapped in the spleen or lymph nodes, or a combination of factors, according to the National Heart, Lung, and Blood Institute.
Conditions or diseases that cause problems involving lymphocytes can be either acquired or inherited. One example of an acquired lymphocyte deficiency is AIDS, according to the National Heart, Lung, and Blood Institute. Hereditary lymphocyte deficiencies are rare, and include diseases such as DiGeorge anomoly, Wiskott-Aldrich syndrome, severe combined immunodeficiency syndrome and ataxia-telangiectasia.