Lymphocytes are a type of white blood cell which fight bacterial and viral infections. They are the subset of white blood cells involved in the more specific response to infections, which can identify and differentiate between different foreign organisms that enter the body. As well as fighting infection, they produce antibodies and memory cells to help to prevent future infections from the same germ. Lymphocytes include T cells, B cells and natural killer cells.
What might a low result mean?
Low levels of lymphocytes can arise after an infection such as a common cold, because many of them have been used up when fighting the infection. Stress and intense exercise can also cause levels to drop.
Low levels of lymphocytes can also be seen in people with certain diseases which can cause lymphocyte levels to drop.
What might a high result mean?
Elevated levels of lymphocytes can arise for many reasons, but it is common for them to be raised after recent infection, particularly after the flu. Certain autoimmune conditions such as Grave's disease (an overactive thyroid) and lupus can also cause lymphocyte levels to spike.