Microangiopathic haemolytic anaemia resembling thrombotic thrombocytopenic purpura in systemic lupus erythematosus: the role of ADAMTS13

Thrombotic thrombocytopenic purpura (TTP) is a rare but frequently fatal complication of SLE. It occurs in the context of both active and inactive lupus and carries a worse overall prognosis than idiopathic acquired TTP. Recent advances in the knowledge and treatment of TTP do not seem to have brought similar improvements in the management and outcome of TTP in SLE. The illumination of the role of the von Willebrand factor multimer protease, ADAMTS13 in idiopathic TTP continues to enhance our comprehension of the pathogenesis of the disease and has contributed to improvements in diagnosis and management. We explore the overlap of TTP and SLE, and discuss the current understanding of the involvement of ADAMTS13 and its implications for patients with this uncommon form of microangiopathic haemolytic anaemia.     

Refractory thrombotic thrombocytopenic purpura in a lupus nephritis patient

Thrombotic thrombocytopenic purpura is an uncommon disease and is rare in systemic lupus erythematosus. Rarely, patients do not respond to plasma exchange therapy, and treatment options are limited and often disappointing, thus it is a therapeutic challenge to clinicians. We report a patient with lupus nephritis who developed refractory thrombotic thrombocytopenic purpura and was subsequently treated with cyclosporin A. An immediate and sustained response was demonstrated, and she remained well; eventually she was able to be cyclosporin free after the acute episode. Cyclosporin A can be a safe and effective therapeutic option in patients with refractory thrombotic thrombocytopenic purpura.     

Rituximab in recalcitrant thrombotic thrombocytopenic purpura secondary to systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a typical autoimmune disease with manifestations due to unopposed production of autoantibodies against the patient's own cells. The clinical features are diverse, ranging from musculoskeletal involvement, lupus nephritis to cerebral and even haematological involvement. We report a case of a young woman with known SLE who developed thrombotic thrombocytopenic purpura (TTP) secondary to SLE resistant to conventional treatment with plasma exchange. She was then treated with rituximab (MabThera®), a CD20 monoclonal antibody, and showed remarkable improvement. To our best knowledge this is the first case reporting the use of rituximab in acute resistant TTP secondary to SLE.     

Morphologic diagnosis of thrombotic thrombocytopenic purpura

The diagnosis of thrombotic thrombocytopenic purpura (TTP) rests on evidence of microangiopathic hemolytic anemia and thrombocytopenia in the absence of disseminated intravascular coagulation and other known causes of thrombotic microangiopathy. Highly specific diagnostic tools such as serum levels of ADAMTS13 are not routinely available for immediate clinical diagnosis. The presence of schistocytes on a blood smear is the morphologic hallmark of the disease, but no guidelines exist as to the number of schistocytes required to differentiate TTP from other thrombotic microangiopathies. We studied 6 patients with TTP and compared their schistocyte counts with those of 40 normal subjects, 28 patients with chronic renal disease, 5 with preeclampsia, and 5 with normal functioning mechanical heart valves. The mean schistocyte count for the TTP patients was 8.35% versus 0.05% for normal subjects, 0.2% for renal patients, 0.25% for preeclamptic patients, and 0.18% for patients with mechanical valves (P < 0.001). Schistocytes were found on 100% of blood films of TTP patients and ranged from 1.0% to 18.4% of red cells. Schistocytes are found on the smears of 58% of normal individuals and on 80-100% of the other patient groups studied, but always comprise less than 0.5% of the red cell population. An initial schistocyte count of greater than 1% strongly suggests a diagnosis of TTP in the absence of other known causes of thrombotic microangiopathy.     

Systemic lupus erythematosus presenting as thrombotic thrombocytopenic purpura

We describe a 10-year-old girl, who presented with thrombotic thrombocytopenic purpura (TTP) and shortly thereafter developed systemic lupus erythematosus (SLE). The association between TTP and SLE is known, but this is the first report of SLE presenting as TTP.     

How I treat thrombotic thrombocytopenic purpura and atypical haemolytic uraemic syndrome

Thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS) are acute, rare life‐threatening thrombotic microangiopathies that require rapid diagnosis and treatment. They are defined by microangiopathic haemolytic anaemia and thrombocytopenia, with renal involvement primarily in aHUS and neurological and cardiological sequelae in TTP. Prompt treatment for most cases of both conditions is with plasma exchange initially and monoclonal therapy (rituximab in TTP and eculizumab in aHUS) as the mainstay of therapy. Here we discuss the diagnosis and therapy for both disorders.     

血栓性血小板减少性紫癜临床诊断与治疗

血栓性血小板减少性紫癜(TTP)是一种以微血管病性溶血性贫血和血小板减少为主要特征,常伴有神经精神症状,肾脏损害,发热等症状和体征的血栓性微血管病.由于该病发病率相对较低,临床表现和实验室检查缺乏特异性,加之TIP典型"五联征"(血小板减少、微血管病溶血性贫血、发热、神经精神症状、肾功能损害)仅见于少数患者(<40%),故对血液科临床医生而言,TTP仍是较难诊断的一种疾病.     

Systemic lupus erythematosus presenting as fulminant thrombotic thrombocytopenic purpura]

A 20-year-old woman visited a nearby hospital because of sudden, severe, and unusual genital bleeding. She also exhibited severe anemia and thrombocytopenia. In transit to our hospital, the patient suddenly suffered cardiac arrest and died soon thereafter despite immediate blood transfusion and therapeutic intubation. Thrombotic thrombocytopenic purpura (TTP) was initially diagnosed at autopsy due to the observation of numerous fragmented erythrocytes in peripheral blood, evidence of hemolysis, and thrombotic microangiopathy in multiple organs. In addition, histopathologic and serologic findings disclosed an association with systemic lupus erythematosus (SLE). Test for anticardiolipin antibody was positive, and hemophagocytic findings were detected in lymph node specimens. Reports of TTP in association with SLE have been increasing in recent years. However, the mechanisms correlating these two illnesses have not been identified. We speculated that the rapid clinical course in this case was attributable to TTP that had been provoked by endothelial microangiopathy due to SLE, and moreover, the fact that the patient's general condition had been seriously complicated by excessive menstrual bleeding.     

Pathogenesis of thrombotic thrombocytopenic purpura

The recent discovery of important molecular and genetic mechanisms of thrombotic thrombocytopenic purpura and hemolytic uremic syndrome provide an opportunity to reconstruct scientific and clinical paradigms. Acquired and congenital defects of the metalloprotease ADAMTS13 are a central feature in the pathogenesis of a major type of thrombotic microangiopathy. This and other pathogenic mechanisms can redefine the terminology of thrombotic microangiopathy. Deficient activity of ADAMTS13 suggests several possible models of microvascular thrombosis. The sporadic relationship between thrombotic microangiopathy and ADAMTS13 deficiency draws attention to other critical pathologic factors that are still poorly understood. Investigation of vascular injury and mechanisms of microvascular thrombosis remain the frontiers of investigation in thrombotic microangiopathy.     

Treatment of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP), characterized by thrombocytopenia and microangiopathic haemolytic anaemia, was almost universally fatal until the introduction of plasma exchange (PE) therapy in the 1970s. Based on clinical studies, daily PE has become the first-choice therapy since 1991. Recent findings may explain its effectiveness, which may include, in particular, the removal of anti-ADAMTS13 autoantibodies and unusually large von Willebrand factor multimers and/or supply of ADAMTS13 in acquired idiopathic or congenital TTP. Based on currently available data, the favoured PE regimen is daily PE [involving replacement of 1-1.5 times the patient's plasma volume with fresh-frozen plasma (FFP)] until remission. Adverse events of treatment are mainly related to central venous catheters. The potential reduction of plasma related side-effects, such as transfusion-related acute lung injury (TRALI) or febrile transfusion reactions by use of solvent-detergent treated (S/D) plasma instead of FFP is not established by controlled clinical studies. Uncontrolled clinical observations and the hypothesis of an autoimmune process in a significant part of the patients with acquired idiopathic TTP suggest a beneficial effect of adjunctive therapy with corticosteroids. Other immunosuppressive treatments are not tested in controlled trials and should be reserved for refractory or relapsing disease. There is no convincing evidence for the use of antiplatelet agents. Supportive treatment with transfusion of red blood cells or platelets has to be evaluated on a clinical basis, but the transfusion trigger for platelets should be very restrictive. Further controlled, prospective studies should consider the different pathophysiological features of thrombotic microangiopathies, address the prognostic significance of ADAMTS13 and explore alternative exchange fluids to FFP, the role of immunosuppressive therapies and of new plasma saving approaches as recombinant ADAMTS13 and protein A immunoadsorption.     

Pathophysiology of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a disorder with characteristic von Willebrand factor (VWF)-rich microthrombi affecting the arterioles and capillaries of multiple organs. The disorder frequently leads to early death unless the patients are treated with plasma exchange or infusion. Studies in the last decade have provided ample evidence to support that TTP is caused by deficiency of a plasma metalloprotease, ADAMTS13. When exposed to high shear stress in the microcirculation, VWF and platelets are prone to form aggregates. This propensity of VWF and platelet to form microvascular thrombosis is mitigated by ADAMTS13, which cleaves VWF before it is activated by shear stress to cause platelet aggregation in the circulation. Deficiency of ADAMTS13, due to autoimmune inhibitors in patients with acquired TTP and mutations of the ADAMTS13 gene in hereditary cases, leads to VWF–platelet aggregation and microvascular thrombosis of TTP. In this review, we discuss the current knowledge on the pathogenesis, diagnosis and management of TTP, address the ongoing controversies, and indicate the directions of future investigations.     

Fatal thrombotic thrombocytopenic purpura in a patient with systemic lupus erythematosus

An immunologic mechanism, possibly immune complex mediated, has been suggested as the basis for the pathogenesis of thrombotic thrombocytopenic purpura (TTP). The evidence supporting this concept has been the association of TTP with systemic lupus erythematosus and the successful therapy of TTP by plasmapheresis. However, most investigators have failed to demonstrate elevated circulating immune complexes during the course of TTP. This report describes a young woman with systemic lupus who developed TTP as a terminal event. Elevated levels of immune complexes were associated with periods of active lupus but were not detectable at the time she developed TTP.     

Recurrent thrombotic thrombocytopenic purpura in a patient with systemic lupus erythematosus

Abstract

We encountered a 39-year-old female patient with systemic lupus erythematosus (SLE) in whom thrombotic thrombocytopenic purpura (TTP) recurred. The patient was successfully treated with corticosteroid in combination with immunosuppressive agents. Because TTP complicating SLE is more resistant to treatment than idiopathic TTP, prompt diagnosis and efficacious initial treatment are critical.