Reactive lymphocyte

In general, those cells may vary in morphologic detail as well as surface marker characteristics since this is the result of a polyclonal immune response to antigenic stimulation.

[7][5] Reactive lymphocytes have been found to accumulate in areas of inflammation like the liver and pharynx of individuals with infectious mononucleosis and skin window preparations.

In infectious mononucleosis, the atypical lymphocytes are one component of a normal immune system that helps to control potentially fatal Epstein-Barr virus-induced B-cell lymphoma in human.

Reactive lymphocytes are usually associated with viral illnesses, but they can also be present as a result of drug reactions (such as phenytoin), immunizations, radiation, and hormonal causes (such as stress and Addison's disease), as well as some autoimmune disorders (such as rheumatoid arthritis).

[9][10] Some observations even suggest that the presence of particular reactive lymphocytes in some of the infected patients could be an indicator of a better prognosis of the disease.