(Medical Immunology, p. 122)

Lymphocytes have a number of alarming properties such as the ability to wander around the body and take up lodging almost anywhere, and while on the way issue commands in the form of cytokines and chemokines and lymphokines, commands that affect many cell types in the body and which may also recursively induce further lymphopoiesis.One strong behavior pattern that captivates researchers and the public alike is the ability of lymphocytes to act as police, judge and executioner to kill other cells or demand that they suicide, a command that is usually obeyed.