- [Show abstract] [Hide abstract] ABSTRACT: Hereditary thrombotic thrombocytopenic purpura, Upshaw-Schulman syndrome, ADAMTS13 Hereditary thrombotic thrombocytopenic purpura (TTP), also known as Upshaw-Schulman syndrome, is a rare recessively inherited disease. Underlying is a severe constitutional deficiency of the von Willebrand factor-cleaving protease, ADAMTS13, due to compound heterozygous or homozygous mutations in the ADAMTS13 gene. The clinical picture is variable and more and more patients with an adult-onset are diagnosed. In the majority of countries the only available treatment is plasma, which when administered regularly can efficiently prevent acute disease bouts. The decision to initiate regular prophylaxis is often not easy, as evidence based guidelines and long term outcome data are lacking. Through the hereditary TTP registry (www.ttpregistry.net, ClinicalTrials.gov identifier: NCT01257269), which was initiated in 2006 and is open to all patients diagnosed with Upshaw-Schulman syndrome and their family members, we aim to gain further information and insights into this rare disease, which eventually will help to improve clinical management of affected patients.
- [Show abstract] [Hide abstract] ABSTRACT: The Oklahoma Thrombotic Thrombocytopenic Purpura-Haemolytic Uraemic Syndrome (TTP-HUS) Registry has a 24 year record of success for collaborative clinical research, education, and patient care. This article tells the story of how the Registry began and it describes the Registry's structure and function. The Registry provides a model for using a cohort of consecutive patients to investigate a rare disorder. Collaboration between Oklahoma, United States and Bern, Switzerland has been the basis for successful interpretation of Registry data.Registry data have provided new insights into the evaluation and management of TTP. Because recovery from acute episodes of TTP has been assumed to be complete, the increased prevalence of hypertension, diabetes, depression, and death documented by long-term follow-up was unexpected. Registry data have provided opportunities for projects for students and trainees, education of physicians and nurses, and also for patients themselves. During our follow-up, patients have also educated Registry investigators about problems that persist after recovery from an acute episode of TTP. Most important, Registry data have resulted in important improvements for patient care.
- [Show abstract] [Hide abstract] ABSTRACT: Romiplostim is a peptibody protein that raises platelet counts during long-term treatment of patients with chronic immune thrombocytopenia (ITP). Clinical outcomes related to increased platelet counts include a reduced risk of bleeding and a potential risk of thrombosis. To evaluate bleeding and thrombotic events occurring in chronic ITP patients during two phase 3, randomized, placebo-controlled, 24-week studies of romiplostim and during subsequent treatment in an open-label extension study. In the phase 3 trials, 125 patients were randomized to romiplostim or placebo; romiplostim dose was adjusted to maintain platelet counts of 50-200 x 10(9) L(-1). Patients who completed the phase 3 trials could enroll in the extension study in which all patients received romiplostim. In the phase 3 trials, a significantly greater percentage of patients treated with placebo (34%) had bleeding adverse events of moderate or greater severity than did patients treated with romiplostim (15%, P = 0.018). In the extension study, the incidence of bleeding adverse events of moderate or greater severity decreased from 23% of patients in the first 24 weeks to 12% after 24-48 weeks, remaining < or = 6% thereafter. The exposure-adjusted incidence of thrombotic events was 0.1 per 100 patient-weeks in the phase 3 studies, and 0.08 per 100 patient-weeks in the extension study where patients received romiplostim for up to 144 additional weeks. The incidence and severity of bleeding was decreased in chronic ITP patients treated with romiplostim compared with placebo, and the incidence of thrombotic events was not different between the two groups.
- [Show abstract] [Hide abstract] ABSTRACT: In immune thrombocytopenic purpura (ITP), thrombocytopenia is a result of both increased platelet destruction and insufficient platelet production. In adults, the course is commonly chronic, but most patients never experience serious bleeding even with severe thrombocytopenia. In case series of consecutive adult patients identified at the time of diagnosis, the frequency of death from bleeding is low, < 1%. The goal of treatment is only to prevent bleeding, not to correct the platelet count to normal. All current treatments are designed to diminish the increased platelet destruction, either by immunosuppression or splenectomy. The frequency of death from complications of treatment is similar to the frequency of death from bleeding. Perhaps because of increasing recognition of both the infrequent occurrence of serious bleeding and the risks of immunosuppressive treatment and splenectomy, data from case series across the past 30 years suggest a trend toward less therapy and fewer splenectomies among patients with ITP. However treatment is necessary for patients with severe and symptomatic thrombocytopenia. Splenectomy remains the most effective treatment for ITP, with two-thirds of patients achieving durable complete remissions. Immunosuppressive agents, including rituximab and combinations of agents, may be less effective than splenectomy in achieving complete remissions and the remissions may also be less durable. New agents for patients with ITP are currently in development that enhance platelet production, rather than diminish platelet destruction. In preliminary reports, these agents have been effective in maintaining safe platelet counts in patients with chronic ITP that was refractory to splenectomy and other treatments.
- [Show abstract] [Hide abstract] ABSTRACT: The function of blood platelets to prevent blood loss at injured sites in the vasculature depends largely on their capacity to adhere, aggregate, promote coagulation and secrete factors that induce vasoconstriction and recruit inflammatory cells. Produced in large numbers from megakaryocytes, platelets enter the circulation for 7-10 days primed to fulfill their hemostatic function. By 1970, thoughts were becoming well formulated concerning the involvement of platelets not only in hemostasis, but also in the pathogenesis of arterial thrombosis. By this timeframe, pioneering studies had also established many of the basic concepts of platelet biology. Physiologic agonists of platelet aggregation such as ADP, collagen and thrombin had already been identified. Protein cofactors including von Willebrand factor (VWF) and fibrinogen were known to be involved in platelet aggregation (1). However, in the background of these basic studies, the elegant morpholo- gical characterizations of platelets by investigators such as Jim White and Dorothea Zucker-Franklin were teaching us that that the two primary activities of platelets in thrombosis and hemostasis, that is adhesion and aggregation, were dependent upon as yet undescribed elements on the platelet membrane surface. It was also clear that this surface had procoagulant activity. While important studies had been initiated to study platelet membrane proteins, for example, the work in Graham Jamieson's laboratory to characterize peptide fragments of membrane proteins released by proteases (2-5), and the contri- butions of Ralph Nachman's laboratory on platelet membrane protein content (6,7), further progress in our understanding of thrombosis and hemostasis required defining the protein content of the platelet membrane surface and identifying specific proteins that were involved in platelet function. What follows is a story of collaborative research that began 30 years ago and has lasted across our careers. The ability to label platelet surface glycoproteins with radioisotopes and to solubilize them in sodium dodecyl sulfate (SDS) and separate them by polyacrylamide gel electrophoresis (PAGE) was an important advance that provided the basis for each of our projects. Using these techniques, each of us began with different perspectives and different goals. Our ideas all came together in 1975 at the meeting of the International Society for Thrombosis and Haemostasis (ISTH) in Paris. By that time we appreciated the complexity of the platelet membrane glyco- proteins and understood that they had important roles in platelet function, documented by their abnormalities in the congenital disorders, Glanzmann thrombasthenia and Bernard-Soulier syndrome. Many of the other early investiga- tors in this field are to be found in Fig. 1, a group photograph taken at am eeting held in San Antonio, Texas in 1983 to develop our book, Platelet Membrane Glycoproteins (Fig. 2) (8). But to tell the story of how the three of us arrived at this point requires that we begin again, each of us on our own.
- [Show abstract] [Hide abstract] ABSTRACT: Accurate estimates of the incidence of thrombotic thrombocytopenic purpura (TTP) are important to assess the resources required for current treatments as well as to anticipate the need to develop new treatments. Previous estimates have been indirect and have not reported data on patients with ADAMTS-13 deficiency. To determine the incidence of patients with TTP-hemolytic uremic syndrome (HUS) in three categories: all patients with clinically suspected TTP-HUS, patients with idiopathic TTP-HUS, and patients with severe ADAMTS-13 deficiency. Incidence rates were estimated from the Oklahoma TTP-HUS Registry, analyzing all 206 consecutive patients from January 1, 1996 to June 30, 2004 who were treated with plasma exchange for their initial episode of clinically suspected TTP-HUS. ADAMTS-13 activity was measured in 186 (90%) of the 206 patients. The age-sex-race standardized annual incidence rates were 11.29 x 10(6) (95% CI: 9.70-12.88) for all patients with clinically suspected TTP-HUS; 4.46 x 10(6) (95% CI: 3.43-5.50) for patients with idiopathic TTP-HUS; and 1.74 x 10(6) (95% CI: 1.06-2.41) for patients with severe ADAMTS-13 deficiency (<5% activity). In all three categories, the incidence rates were greater for women and for blacks. For patients with severe ADAMTS-13 deficiency, the age-sex standardized incidence rate ratio of blacks to non-blacks was 9.29 (95% CI: 4.33-19.93). Accurate incidence rate estimates for all patients with clinically suspected TTP-HUS, idiopathic TTP-HUS, and TTP associated with severe ADAMTS-13 deficiency have been determined. The greater incidence among women and blacks is comparable with their increased risk for other autoimmune disorders.
- [Show abstract] [Hide abstract] ABSTRACT: BACKGROUND: With the increased frequency of diagnosis and improved survival of thrombotic thrombocytopenic purpura-hemolytic-uremic syndrome (TTP-HUS), the morbidity of plasma exchange (PE) treatment has become more important.STUDY DESIGN AND METHODS: Data were prospectively collected on 71 consecutive patients referred to the Oklahoma Blood Institute (OBI) for PE treatment for clinically suspected TTP-HUS from mid-1996 to mid-1999. Complications were defined as major or minor, and distinguished between those related to central venous catheter access or to the plasma.RESULTS: Twenty-one patients (30%) had 27 major complications, which caused two deaths. The major complications included 2 episodes of hemorrhage after subclavian line insertion (1 death), 1 pneumothorax requiring a chest tube, 12 systemic infections (1 death), 7 episodes of catheter thrombosis requiring removal of the central venous catheter, 2 episodes of venous thrombosis requiring anticoagulant treatment, 2 episodes of hypoxemia and hypotension, and 1 episode of serum sickness. Minor complications occurred in 22 additional patients (31%). Twenty-eight patients (39%) had no complications.CONCLUSIONS: The morbidity and mortality of catheter placement and PE are important considerations when PE treatment for clinically suspected TTP-HUS is anticipated.
- [Show abstract] [Hide abstract] ABSTRACT: Since idiopathic (immune) thrombocytopenic purpura (ITP) in adults is usually a chronic condition with few spontaneous remissions, the goal of treatment is not cure, but to maintain a hemostatically safe platelet level. The indication for treatment should be based not merely on platelet counts, but also clinical indices of bleeding. Although most patients show good initial response to prednisone, the side effects of steroids limit this treatment. Currently, long-term management usually involves splenectomy. Since splenectomy has surgical risks and may also predispose the patient to sepsis, a clinical trial using anti-D (WinRho-SDR) has been performed to determine whether this treatment can safely delay or avoid the need for surgery. The use of WinRho may also reveal the occurrence of spontaneous remissions, a previously unrecognized subgroup of adults with chronic ITP.
- [Show abstract] [Hide abstract] ABSTRACT: Quinine-associated thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is thought to be uncommon and to have a good prognosis. To describe the frequency, clinical features, and long-term outcomes of quinine-associated TTP-HUS. Case series. Hospitals in central-western Oklahoma. 225 consecutive patients with TTP-HUS, 1989-2000. Presenting features and clinical outcomes. Thrombotic thrombocytopenic purpura-hemolytic uremic syndrome was associated with quinine in 17 patients. Four patients died, and 7 survivors currently have chronic renal failure. Since 1 July 1995, 132 patients with clinically suspected TTP-HUS were explicitly asked about drug exposure. Fourteen (11%) had taken quinine, and 7 had taken other drugs associated with TTP-HUS. Neurologic abnormalities were as severe in patients with quinine-associated TTP-HUS as in the 118 patients who had not taken quinine. Quinine is a common cause of drug-associated TTP-HUS and can cause death and chronic renal failure. When the disorder is described as TTP-HUS rather than only as HUS, the severity of neurologic abnormalities and the occasional absence of renal failure are emphasized. If recurrent disease is to be prevented, clinicians must recognize quinine as a possible cause.
- [Show abstract] [Hide abstract] ABSTRACT: Prompt recognition of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) and initiation of plasma exchange treatment is critical as it substantially decreases mortality. Nevertheless, death and long-term complications remain common. The recent relaxation of diagnostic criteria has dramatically increased the number of patients treated for clinically suspected TTP-HUS.
- [Show abstract] [Hide abstract] ABSTRACT: The diagnosis and treatment of thrombotic thrombocytopenic purpura (TTP) in patients following BMT are often uncertain and unsuccessful. To better understand the evaluation and management of these patients, we describe 17 patients treated with plasma exchange for a presumptive diagnosis of TTP following BMT during a 10 year period, 1989-1998. Because of the uncertainty of the diagnosis, these patients are described as having a 'TTP-like syndrome'. All 17 patients had received an allogeneic BMT. Comparison with the other 245 patients who had an allogeneic BMT during the same period demonstrated that patients with a TTP-like syndrome more frequently had unrelated and/or HLA-mismatched donors, and had also experienced more serious complications: grade III-IV acute GVHD and systemic bacterial, fungal, and viral infections. Three months after the diagnosis of the TTP-like syndrome, only four of 17 patients (24%) were alive; currently only one patient survives. These data emphasize: (1) the diagnosis of TTP following BMT is uncertain because of the presence of multiple BMT-associated complications. (2) The outcome of patients with TTP-like syndromes following BMT is poor. (3) Urgent intervention with plasma exchange when TTP is suspected following BMT may not always be appropriate. Alternative explanations for the signs and symptoms should be considered and treated aggressively.
- [Show abstract] [Hide abstract] ABSTRACT: Therapeutic plasmapheresis may remove platelets as well as plasma. Unintentional platelet loss, if not recognized, may lead to inappropriate patient assessment and treatment. A patient with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome (TTP-HUS) is reported in whom persistent thrombocytopenia was interpreted as continuing active disease; thrombocytopenia resolved only after plasma exchange treatments were stopped. This observation prompted a systematic study of platelet loss with plasmapheresis. Data are reported on platelet loss during 432 apheresis procedures in 71 patients with six disease categories using three different instruments. Comparing the first procedure recorded for each patient, there was a significant difference among instrument types (P<0.001); platelet loss was greater with the Fresenius AS 104 (17.5%, N = 21) than with the COBE Spectra (1.6%, N = 26) or the Haemonetics LN9000 (2.6%, N = 24). With all procedures, platelet loss ranged from 0 to 71%. Among disease categories, platelet loss was greater in patients with dysproteinemias who were treated for hyperviscosity symptoms. Absolute platelet loss with the first recorded apheresis procedure, in the 34 patients who had a normal platelet count before the procedure, was also greater with the AS 104 (2.23 x 10(11) platelets) than with the Spectra (0.29 x 10(11) platelets) or the LN9000 (0.37 x 10(11) platelets). In 39 patients in whom data were collected on consecutive days, platelet removal by plasmapheresis correlated with a decreased patient platelet count (r = 0.40, P = 0.011). In these 39 patients, the platelet counts were significantly decreased at 24 hours (P = 0.002).
- [Show abstract] [Hide abstract] ABSTRACT: Quinine is universally used for the very common symptom of night leg cramps. Patients may not mention it among their medicines, since it is so commonly used and they regulate it themselves. A 68-year-old man suddenly developed extensive bleeding due to severe thrombocytopenia. The diagnosis was initially thought to be a recurrence of idiopathic thrombocytopenic purpura (ITP) that had initially occurred in 1992 and had required splenectomy. Drug-induced thrombocytopenia was also considered, and he was told to stop all of his medicines. Only after three subsequent episodes of severe, symptomatic thrombocytopenia over the next four weeks did he say, upon repeat questioning, that he had continued to take quinine for night leg cramps. Even after a strict warning, he took another quinine tablet that evening, which triggered his fifth episode of severe thrombocytopenia, and confirmed the etiology of quinine-induced thrombocytopenia. The diagnosis thrombocytopenia caused by common drugs can be difficult, requiring persistent, explicit questions.
- [Show abstract] [Hide abstract] ABSTRACT: With the increased frequency of diagnosis and improved survival of thrombotic thrombocytopenic purpura-hemolytic-uremic syndrome (TTP-HUS), the morbidity of plasma exchange (PE) treatment has become more important. Data were prospectively collected on 71 consecutive patients referred to the Oklahoma Blood Institute (OBI) for PE treatment for clinically suspected TTP-HUS from mid-1996 to mid-1999. Complications were defined as major or minor, and distinguished between those related to central venous catheter access or to the plasma. Twenty-one patients (30%) had 27 major complications, which caused two deaths. The major complications included 2 episodes of hemorrhage after subclavian line insertion (1 death), 1 pneumothorax requiring a chest tube, 12 systemic infections (1 death), 7 episodes of catheter thrombosis requiring removal of the central venous catheter, 2 episodes of venous thrombosis requiring anticoagulant treatment, 2 episodes of hypoxemia and hypotension, and 1 episode of serum sickness. Minor complications occurred in 22 additional patients (31%). Twenty-eight patients (39%) had no complications. The morbidity and mortality of catheter placement and PE are important considerations when PE treatment for clinically suspected TTP-HUS is anticipated.
- [Show abstract] [Hide abstract] ABSTRACT: Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are, in adults, clinically and pathologically indistinguishable except for the severity of renal failure. They are best described as a single disorder, TTP-HUS, because the diagnostic evaluation and initial management are the same. Treatment with plasma exchange, available for more than 20 years, has dramatically altered the course of disease in adults with TTP-HUS. Plasma exchange has improved survival rates from 10% to between 75% and 92%, creating urgency for the initiation of treatment. This has resulted in decreased stringency of diagnostic criteria, which in turn has resulted in a broader spectrum of disorders for which the diagnosis of TTP-HUS is considered. Long-term follow-up has revealed increasing frequencies of relapse and of chronic renal failure. Although the increased survival rate is dramatic and recent advances in understanding the pathogenesis of these syndromes are remarkable, clinical decisions remain empirical. Therefore, the management decisions for patients with suspected TTP-HUS rely on individual experience and opinion, resulting in many different practice patterns. Multipractice clinical trials are required to define optimal management. (Blood. 2000;96:1223-1229)
University of Oklahoma Health Sciences Center
Oklahoma City, Oklahoma, United States
- • Section of Hematology/Oncology
- • Department of Biostatistics and Epidemiology
Oklahoma City UniversityOklahoma City, Oklahoma, United States