[Differentiation, crossregulation and roles of Th1 and Th2 cells in multiple sclerosis]

Most of immunopathological knowledge on multiple sclerosis(MS) is from studies based on the hypothesis that MS is a Th1 disease. Understanding differentiation and crossregulation of Th1 and Th2 cells is pivotal to grasp the immunological theories of MS. However, one need be aware that Th1 disease hypothesis may not represent all of MS because effector cells as well as regulatory cells have not been firmly identified. In addition, a few EAE studies and clinical trials suggest that Th1 cytokine could be protective and that Th2 cells could be encephalitogenic although much more studies have supported the hypothesis. Here basic knowledge about helper T cells is first described. And then, the rationale of the Th1 disease hypothesis is discussed.