Therapeutic modality of 11 patients with TTP in a single institution in Miyazaki from 2000 to 2011

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening generalized disease with pathological features that are termed thrombotic microangiopathies. Since the discovery of the von Willebrand factor-cleaving protease [a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13)], it is widely known that approximately two-thirds of TTP patients have a severe deficiency of ADAMTS13 activity due to gene mutations or acquired autoantibodies to this enzyme. However, the remaining one-third of TTP patients have only moderately reduced or almost normal ADAMTS13 activity. To elucidate the clinical characteristics and outcomes of these two types of TTP, we have retrospectively analyzed the cases of acquired TTP patients treated in a single institution from 2000 to 2011.

Our case studies include 11 TTP patients, of which 5 were considered idiopathic and 6 had cases of TTP associated with underlying diseases such as non-Hodgkin lymphoma or connective tissue diseases.

These patients were treated with a combination therapy of plasma exchange and steroids and with several adjunctive therapeutic regimens including the on-label use of cyclophosphamide and cyclosporine and the off-label use of high-dose steroid or immunoglobulin with rituximab. Splenectomies were not performed. As a result of these treatments, 6 out of the 7 patients with ADAMTS13 activity deficient TTP achieved a complete remission without relapse, but the remaining 4 patients with non-ADAMTS13 activity deficient TTP all died without complete remission.

We present herein the detailed clinical courses of 11 patients with TTP and address our experiences with the efficacy of various therapeutic regimens. This case-oriented study should be helpful to the physicians who directly care for TTP patients, and may provide a future direction for developing a more efficient treatment modality.