A lymphocyte is a type of immune cell. Immune cells are responsible for protecting our body from infections and for helping us heal after an injury. There are several different types of lymphocytes including T-lymphocytes, B-lymphocytes, plasma cells, and natural killer cells. Each cell type has a different function in the body.
Pathologists commonly describe large groups of lymphocytes as chronic inflammatory cells because their activity in a tissue lasts longer than other types of inflammatory cells.
When examined under the microscope, it is normal to see lymphocytes in most types of tissue. Increased numbers of lymphocytes can be seen under the microscope after an injury or in medical conditions associated with long-term or chronic inflammation.
Although lymphocytes are designed to protect our body and help us heal, some medical conditions are caused by lymphocytes damaging our tissue. These types of medical conditions include inflammatory and autoimmune diseases.
Examples of medical conditions caused by lymphocytes: