Since I became ill I have a flu-like feeling in my body and head all the time. I could not make sense of this, because there is no coughing or sneezing along with it. I was also confused when I read articles about having an immune deficiency, and articles about an over-active immune system. It seemed contradictory. Well, I just read that T Helper cells (which are part of the immune system) switch on and off. And when they are on, they are in one of two active modes. Each mode fights a different kind of attack on the body's cells. And in the case of many people with CFS, the cells are constantly turned on to fight one type of invader, while ignoring others. And the problem is the body can't switch back and forth and on and off anymore. It is also my understanding that another part of our immune system (the Natural Killer Cells) become deficient in this state. (My tests actually show this.) I think this might also explain why I feel like I have the flu all the time. That feeling comes from the body be revved up to fight certain types of infections, even though it is ignoring others. Anyway, I'm no expert. But this is what came to me recently.