Most patients have few, if any, symptoms of lymphocytosis, according to Mayo Clinic. Some patients may experience symptoms of conditions linked to lymphocytosis, which include inflammatory autoimmune diseases, lymphatic and blood cancers, and viral and bacterial infections. Lymphocytosis also may be a temporary response following an illness.
Lymphocytosis refers to an above-normal amount of white blood cells, Mayo Clinic explains. White blood cells, also called lymphocytes, help the body fight disease, so it is common to have a higher count during and after contracting a viral or bacterial infection.
In a healthy adult, lymphocytes usually number around 3,000 in a microliter of blood, Mayo Clinic states. If significantly more than 3,000 white blood cells are found during a blood test, the patient may be diagnosed with lymphocytosis. In children, a normal white blood cell count varies with age.
Common infections that cause lymphocytosis include mononucleosis, cytomegalovirus, whooping cough, HIV/AIDS and tuberculosis, Mayo Clinic reports. Lymphocytosis is also linked to inflammatory conditions such as vasculitis.
Cancers associated with lymphocytosis include multiple myeloma, as well as both chronic and acute lymphocytic leukemia, Mayo Clinic says. Most doctors will order additional tests to confirm a cancer diagnosis.
Often lymphocytosis isn't a health concern, Mayo Clinic states. A high white blood cell count can indicate that the patient recently fought off a common viral or bacterial infection. The doctor usually determines if lymphocytosis is a symptom of a more serious illness.