Accumulating evidence implicates a failure of myelin-reactive immune cells to undergo apoptosis in the pathological events contributing to multiple sclerosis (MS). We have recently demonstrated that members of the inhibitor of apoptosis (IAP) family of anti-apoptotic genes are elevated in peripheral blood immune cells (monocytes, T cells) of patients with aggressive forms of MS (secondary progressive) or those with relapsing-remitting MS suffering a disease replase. These findings suggest that the IAPs may be novel diagnostic markers for distinguishing subtypes of MS. Moreover, antisense-mediated knockdown of the IAP family member known as X-linked IAP (XIAP) reverses paralysis in an animal model of MS suggesting that treatments targeting XIAP, and perhaps other IAPs, may have utility in the treatment of MS.