Rationale and efficacy for the use of rituximab in paraneoplastic pemphigus.

Paraneoplastic pemphigus (PNP) is a life-threatening, autoimmune, blistering-skin disease, associated with various neoplasms, particularly lymphoproliferative disorders. It is characterized by polymorphic cutaneous manifestations, severe mucosal erosions and internal organ involvement, and marked by unique histopathological features and a complex autoantigenic profile. To define this condition, the encompassing term 'paraneoplastic autoimmune multiorgan syndrome' has also been suggested. Although a number of immunosuppressive treatments have been used in PNP, its mortality rate remains high. The anti-CD20 monoclonal antibody, rituximab, was successfully administered to two patients with PNP and CD20(+) follicular lymphoma in 2001. Since then, good responses to rituximab by different refractory autoimmune disorders have been reported, but further controlled trials are warranted to evaluate the effectiveness and safety of this agent as a second-line treatment for PNP.