Armored Personal Carrier. I think the APC is located where you find the Warden Crossbow.
Autoimmune diseases arise from an overactive immune response of the body against substances and tissues normally present in the body. In other words, the body actually attacks its own cells. An immune disorder is when the body cannot defend itself. [ Source: http://www.chacha ....n immune disorder is when the body cannot defend itself. [ Source: http://www.chacha.com/question/what-is-the-difference-between-immune-disorders-and-autoimmune-diseases ]. More Answers to  What is the difference between immune disorders and autoimmune diseases .
Unlike some diseases, autoimmune diseases do not generally have a simple, single cause. There are usually two major categories of factors that are involved in causing autoimmune diseases: genetics and environment. Virtually every autoimmune disease combines these two.