Its function is much like that of national defense, except that a national defense can tell whether an intruder is friendly or hostile, while the body's immune system cannot tell 'friend or foe' and has no mercy on the transplanted organs. "
可惜的是，國家安全系統可以區分來者是友邦使節抑或敵人，但是人體免疫系統卻是『敵友不分』，對侵入的病毒和細菌固然會發動猛攻，對移植的器官也毫不留情。」