From a medical perspective, autoimmunity reflects the abnormal behaviour of a human being. This state is shaped when the defense of an organism betrays its own tissues. Allegedly, the immune system should protect the body against attacking cells. When an autoimmune disease attacks, it results in perilous actions like self-destruction. However, from a psychological perspective, the French philosopher Jacques Derrida (1930-2004) explains that autoimmunity harms both the self and the other. As a result, the organ disarms the betraying cells, as the immune system cannot provide necessary protection. From a literary perspective, Derrida has termed autoimmunity as deconstruction for almost forty years. Autoimmunity starts with the stage of a normal human feeling of doubt, in which a person can be cured through evidences. In this phase, the doubter is looking for answers and may be convinced when proof is shown. However, when doubt develops further it transforms into skepticism. Here, it is harder to convince a skeptic with proof because the feelings of pride, jealousy and bad temper are involved. Therefore, skepticism is more difficult to cure than doubt. When skepticism is left untreated, the sufferer becomes selfish and chooses violence. This leads to autoimmune diseases in which the person is ready to harm the self and others to obtain her/his goal. So autoimmunity revolutionizes the common human behaviour turning it into an animalistic one. The aim of this paper is to examine Dan Brown's novel The Da Vinci Code (2003), to mirror how people should always expect autoimmune attacks in the future. The novel bears two autoimmune followers who should be a part of the autoimmune body. The follower is thus a cell that is a part of the body (the leader), but the body decides to get rid of what should be part of him. Keywords: Autoimmunity, animalistic behaviour, the self and the other, political terrorism.