Are all symptoms caused by the response of the immune system? Are there any virus that won't be recognized as an "enemy"? Then if one is infected by this kind of virus, does it means he will die without any symptoms?
Cytopathic viruses can cause symptoms directly by just killing cells, but this is due to loss of function of the cells. The Innate immune system does not discriminate one virus from another, so will respond to any virus. However, if the virus is cleared quickly, there may not be any symptoms at all. You would not die without some symptoms indicating a loss of body function.