血栓性血小板減少性紫斑病(TTP)(<特集>血小板減少症とアフェレシス)

概要

論文の詳細を見る
Thrombotic thrombocytopenic purpura (TTP) is a life-threatening generalized disease featured by a 'classic pentad' consisting of hemolytic anemia, thrombocytopenia, renal dysfunction, fever, and fluctuating neurological signs. On the other hand, hemolytic-uremic syndrome (HUS) with prominent nephrological signs is often indistinguishable from TTP, because both the diseases have common pathological conditions termed thrombotic microangiopathies. Since the discovery of ADAMTS13, a von Willebrand factor-cleaving protease, it has been well established that TTP lacks the ADAMTS13 activity due to its gene mutations (termed Upshaw-Schulman syndrome, USS) or acquired auto-antibodies. USS is efficiently treated with simple plasma infusions, whereas the acquired TTP can be treated with plasma exchange (PE), usually together with steroid pulse therapy. Recent studies have further indicated that approximately 20% of patients with acquired TTP have resistance to PE therapy, for whom a diagnosis of 'relapsing or intractable' TTP was made. Our most recent studies have clearly demonstrated that a rapid increase of ADAMTS13 inhibitor titers (boosting) after PE is found in these patients, and therefore an adjunctive strong immunosuppressive therapy is prerequisite to eliminate the antibody-producing B-lymphocytes. Our observations have in part justified the use of rituximab for TTP patients with the inhibitor boosting.
2012-02-29