Just as the causes of some diseases have been known for years, the causes of others are still unclear. This is the case with Parkinson's disease, for example. Scientists are still searching for what actually leads to this serious neurological disease - one recent study argues that immune dysfunction may be linked to Parkinson's disease. Such a discovery not only brings new knowledge as to the aetiology of this condition, but may also be a prelude to developing new treatments for it.