Serum CD95 of relapsing remitting multiple sclerosis patients protects from CD95-mediated apoptosis.

Failure of CD95-mediated apoptosis as a potential negative regulatory mechanism of T cell expansion may be involved in T cell-mediated autoimmune diseases such as multiple sclerosis (MS). Recently, soluble CD95 has been shown to be elevated in MS patients with active disease. Here, we report that the sera of MS patients inhibit CD95 ligand-induced apoptosis of susceptible target cells in a concentration-dependent manner and dependent on the amount of serum CD95 levels. Thus, MS sera contain biologically active inhibitors of T cell apoptosis that may allow for prolonged abnormal immune responses.