What Are Reactive Lymphocytes?

Reactive lymphocytes are a type of lymphocyte that increases in size due to exposure to antigens in the body. Lymphocytes are a type of white blood cell produced by the immune system, and their presence is often due to a viral-based illness. They can also occur in response to certain medications, immunizations, or changes in hormones.

The immune system produces several kinds of white blood cells. Each type has a specific role in protecting the body against antigens. Natural killer cells, T cells, and B cells all work to help protect the body. When stimulated by antigens, any of these cells can grow up to three times their normal size. This growth deems the cells as reactive.

Viral illnesses are one of the most common causes for an increase in reactive lymphocytes. There are many different types of viruses that can make people sick. When a virus invades, such as hepatitis C or cytomegalovirus, the immune system reacts and sends lymphocytes to prevent the virus from taking over and causing damage. In response to the stimulation, the lymphocytes grow in size, almost like swelling.

There are certain prescription medications that can trigger this increase as well. Medications, such as some anti-epileptic prescriptions, are known to cause the body to produce more lymphocytes and stimulate abnormal growth. Although the trigger can be different for each individual person, the body sees the molecules within the medications as an invading antigen.

Similar to a reaction from certain prescription medications, reactive lymphocytes can also be caused by immunizations. Most immunizations are created using inactive versions of the viruses they are supposed to be teaching the body to become immune to. If the body is exposed following an immunization, the immune system automatically begins its seek-and-destroy mission with minimal symptom presentation. Some people have an abnormal reaction to the immunizations, and lymphocytes grow instead of working to defend the body.

Hormonal fluctuations, such as those that occur with Addison’s disease and excessive stress, can also lead to an increase in this type of reaction. Changes in hormone levels can cause many different chemical reactions as the body tries to adjust to large increases or decreases of certain hormones. The immune system can sometimes confuse bodily reactions as an antigen invasion, which in turn causes stimulation of lymphocytes.