Inherited and Acquired Thrombotic Thrombocytopenic Purpura (TTP) in Adults

Thrombotic thrombocytopenic purpura (TTP) is a clearly defined entity of thrombotic microangiopathies (TMAs), a heterogeneous group of disorders characterized by microangiopathic hemolytic anemia with red cell fragmentation, thrombocytopenia, and organ dysfunction due to disturbed microcirculation. TTP is characterized by a severe deficiency of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), an enzyme responsible for physiological cleavage of vonWillebrand factor (VWF). Organ dysfunction can be severe and life threatening, and immediate start of appropriate therapy is necessary to avoid permanent damage or death. The therapeutic options, however, are often limited to symptomatic measures, and are not standardized or based on high scientific evidence. During the last years, not only considerable progress has been made in better diagnosis of TTP, but also new therapeutic strategies have been established. Initial treatment still is based on plasma exchange and symptomatic measures to protect organ function, but new concepts (immunosuppression, targeted anti-VWF or anticomplement therapy, and replacement with recombinant enzymes) are currently under development.