Morphological, physiological and pathological evidence demonstrates that ner- vous and immune systems interact not only in maintaining brain homeostasis, but also in causing neurological diseases. The studyofthese interactions repre- sents the basis on which neuroimmunologyhas grown during the years. At pre- sent, several neurological diseases are recognized to be caused by a derange- ment of the immune system in either its regulatory or effector functions. The main scope ofthis book, to discuss how an unbalanced immune system maylead to immune-mediated neurological diseases, is achieved in three parts. The first part provides an overview on how the immune system works. This is propaedeutical to understanding interactions between the immune and ner- vous systems, which are discussed in the second part. The third part of the book focuses on one particular area of neuroimmunology, the immune disor- ders leading to the damage of central and peripheral myelin. Given the opportunity to review first the immune system in itself and then how it operates during immune-mediated demyelinating disorders, we have tried to provide the reader with a basis for clearly understanding how interac- tions between the immune and nervous systems can be protective or pathoge- nic. This knowledge is a prerequisite for a rationale immune intervention tar- geting these disorders.
