Management of thrombotic thrombocytopenic purpura

Pattern of Brain Injury in Patients With Thrombotic Thrombocytopenic Purpura in the Precaplacizumab Era

OBJECTIVES

To describe short- and long-term neurologic prognosis of patients with thrombotic thrombocytopenic purpura and to identify clusters associated with evolution.

DESIGN

Prospective French cohort.

SETTING

ICU in a reference center.

PATIENTS

All consecutive patients with newly diagnosed thrombocytopenic purpura.

INTERVENTION

Comprehensive clinical, biological, and radiological evaluation at admission. Neurocognitive recovery was assessed using Glasgow Outcome Scale (range 1-5, with 1 representing death and 5 representing no or minimal neurologic deficit).

MEASUREMENTS AND MAIN RESULTS

Among the 130 newly diagnosed patients with thrombocytopenic purpura, 108 (83%; age 43 [30-52]; 73% women) presented with neurologic signs, including headaches (51%), limb weakness, paresthesia, and/or aphasia (49%), pyramidal syndrome (30%), decreased consciousness (20%), seizure (19%), cognitive impairment (34%), cerebellar syndrome (18%), and visual symptoms (20%). A hierarchical cluster analysis identified three distinct groups of patients. Cluster 1 included younger patients (37 [27-48], 41 [32-52], and 48 [35-54], in clusters 1, 2 and 3, respectively; p = 0.045), with a predominance of headaches (75%, 27%, and 36%; p < 0.0001). Cluster 2 patients had ataxic gait and cerebellar syndrome (77%, 0%, and 0%; p < 0.0001) and dizziness (50%, 0%, and 0%; p < 0.0001). Cluster 3 included patients with delirium (36%, 0%, and 9%; p < 0.0001), obtundation (58%, 0%, and 24%; p < 0.0001), and seizure (36%, 0%, and 14%; p < 0.0001). Acute kidney injury was 32%, 68%, and 77%, in clusters 1, 2, and 3, respectively (p < 0.0001). The three clusters did not differ for other biological or brain imaging. After a median follow-up of 34 months (12-71 mo), 100 patients (93%) were alive with full neurocognitive recovery (i.e., Glasgow Outcome Scale score 5) in 89 patients (89%). Patients from cluster 1 more frequently exhibited full recovery (Glasgow Outcome Scale score of 5) compared with clusters 2 and 3, (44 [98%], 13 [65%], and 21 [60%] at 3 mo; p < 0.0001), (44 [100%], 15 [68%], and 23 [69%] at 6 mo; p < 0.0001), and (40 [100%], 15 [79%], and 20 [57%] at 1 yr; p < 0.0001).

CONCLUSIONS

Initial clinical neurologic evaluation in thrombocytopenic purpura patients distinguishes three groups of patients with different clinical and functional outcomes.

Successful Treatment With Bortezomib for Refractory and Complicated Acquired Thrombotic Thrombocytopenic Purpura in an Adolescent Girl

Thrombotic thrombocytopenic purpura (TTP) is a rare, dangerous, life-threatening disease characterized by microangiopathic hemolytic anemia and thrombocytopenia, along with organ dysfunction due to microangiopathy-related ischemia. Plasma exchange and steroids are used for initial treatment, and rituximab is often used in refractive patients. Caplacizumab, cyclophosphamide, and splenectomy are among other treatment options. It has been reported that bortezomib, a proteasome inhibitor, can be used in the management of refractory acquired TTP. Herein, we present a 16-year-old female patient who was monitored for acquired TTP and treated with high-dose steroids, plasma exchange, rituximab, cyclophosphamide, and N-acetylcysteine but developed renal, cardiac, gastrointestinal, and neurologic complications. The girl was then successfully treated with bortezomib, and she has been monitored in remission for 6 months. We consider that bortezomib is a beneficial treatment, especially in patients with refractory TTP.

Plasmic score applicability for the diagnosis of thrombotic microangiopathy associated with ADAMTS13-acquired deficiency in a developing country

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal disease that requires early diagnosis and treatment that can be made possible by applying the PLASMIC score. This study aims to evaluate this score applicability for patients with suspected TTP in a developing country.

METHODS

This was a retrospective study performed at a tertiary hospital in the northeastern region of Brazil. Patients were analyzed in two groups: ADAMTS13 activity <10% and activity >10%. Patients were stratified according to the PLASMIC score, and the level of agreement between the PLASMIC score and the ADAMTS13 activity was evaluated.

RESULTS

Eight patients with thrombotic microangiopathy were included. Four patients had ADAMTS13 activity <10%, all with a PLASMIC score =6. The other four had ADAMTS13 activity >10%, all with a score <6. Based on a score =6 for presumptive diagnosis of TTP, we attained a 100% diagnostic accuracy in our sample. The PLASMIC score was also able to accurately predict response to plasma exchange and the risk of long-term unfavorable outcomes.

CONCLUSIONS

The reproducibility of the PLASMIC score was quite satisfactory in our sample. It accurately discriminates between patients who had ADAMTS13 deficiency and those with normal enzyme activity, precluding the need for specific laboratory evaluation, which is not always available. This score can be useful for an early diagnosis and indicates which patients will benefit from the treatment in developing countries.

Pregnancy shortly after an acute episode of severe acquired thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal condition. In women with a previous history of TTP there is increased risk of recurrence during pregnancy and the puerperium. There is some evidence that the risk of relapse during pregnancy is increased if the interval between the event and conception is short. We present a case in which pregnancy was achieved a few days after full recovery from an acute episode of severe acquired TTP (ADAMTS13 activity <0.1%) which was successfully treated with four courses of plasma exchange. There was no relapse of TTP during pregnancy and a healthy baby was delivered at term; the puerperium was uneventful.

Thrombotic thrombocytopenic purpura (TPP) successfully rescued by plasma exchange in the ICU: A report of two cases

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening disorder, which is characterized by thrombus formation in small blood vessels. The present study retrospectively analyzed the clinical data from two patients with severe TTP, who were treated successfully in the intensive care unit (ICU) at the Liaocheng People's Hospital in 2013. Comprehensive therapies were administered to the patients, including plasma exchange (PE), mechanical ventilation (case 1 only), steroid therapy, blood transfusion and anti-inflammatory treatment (case 2 only). The two patients returned to a stable state and were transferred back to the hematology department following PE. The positive outcome achieved for these patients suggests that early intervention involving bedside PE in the ICU may reduce the mortality rate of patients with severe TTP who have concurrent respiratory or circulatory failure and cannot be treated in the dialysis unit.

Clinical utility of ADAMTS-13 testing in suspected thrombotic microangiopathy: an audit of ADAMTS-13 activity assay requests in routine practice from a tertiary hospital

AIMS

Differentiation between thrombotic thrombocytopenic purpura (TTP) and other microangiopathic haemolytic anaemia (MAHA) processes can be difficult. Since the documentation of ADAMTS-13 deficiency in TTP, several ADAMTS-13 activity assays have been developed for use in the diagnosis of TTP and/or other microangiopathic disorders. We reviewed the clinical utility of ADAMTS-13 activity testing in suspected TTP, as used in routine clinical practice in a tertiary referral hospital.

METHODS

All requests for ADAMTS-13 activity levels performed at our institution after introduction of the assay were retrospectively audited with respect to clinical diagnosis and results.

RESULTS

In total 57 individual patients were tested, of whom only 46% had a MAHA process. Severe ADAMTS-13 deficiency was present in five TTP patients and in one patient with fulminant hepatic failure.

CONCLUSIONS

Our experience suggests that severely reduced levels are relatively specific for TTP, but may also occur in fulminant hepatic failure. Patients without MAHA may have reduced ADAMTS-13 activity and there is significant overlap in the range of ADAMTS-13 activity seen in non-TTP MAHA diagnoses. This supports the observation that outside the diagnosis and (possible) follow-up of suspected idiopathic TTP, the ADAMTS-13 activity assay has limited clinical utility. Further education about the role of ADAMTS-13 activity testing is needed.

ADAMTS-13 in the Diagnosis and Management of Thrombotic Microangiopathies

Thrombotic microangiopathies (TMAs) comprise a group of distinct disorders characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular thrombosis. For many years distinction between these TMAs, especially between thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS), remained purely clinical and hard to make. Recent discoveries shed light on different pathogenesis of TTP and HUS. Ultra-large von Willebrand factor (UL-VWF) platelet thrombi, resulting from the deficiency of cleavage protease which is now known as ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), were found to cause TTP pathology, while Shiga toxins or abnormalities in regulation of the complement system cause microangiopathy and thrombosis in HUS. TMAs may appear in various conditions such as pregnancy, inflammation, malignancy, or exposure to drugs. These conditions might cause acquired TTP, HUS, or other TMAs, or might be a trigger in individuals with genetic predisposition to ADAMTS-13 or complement factor H deficiency. Differentiation between these TMAs is highly important for urgent initiation of appropriate therapy. Measurement of ADAMTS-13 activity and anti-ADAMTS-13 antibody levels may advance this differentiation resulting in accurate diagnosis. Additionally, assessment of ADAMTS-13 levels can be a tool for monitoring treatment efficacy and relapse risk, allowing consideration of therapy addition or change. In the past few years, great improvements in ADAMTS-13 assays have been made, and tests with increased sensitivity, specificity, reproducibility, and shorter turnaround time are now available. These new assays enable ADAMTS-13 measurement in routine clinical diagnostic laboratories, which may ultimately result in improvement of TMA management.

Risk factors and clinical profile of thrombotic thrombocytopenic purpura in systemic lupus erythematosus patients. Is this a distinctive clinical entity in the thrombotic microangiopathy spectrum?: a case control study

INTRODUCTION

The association of thrombotic thrombocytopenic purpura (TTP) with systemic lupus erythematosus (SLE) is rare. It is associated with high morbidity and mortality. Information about risk factors and clinical outcomes is scant.

MATERIAL AND METHODS

A retrospective case-control study was performed in a referral center in Mexico City between 1994 and 2013. Patients were diagnosed with TTP if they fulfilled the following criteria: microangiopathic haemolytic anaemia, thrombocytopenia, high LDH levels, normal fibrinogen and negative Coombs' test. Patients with SLE were diagnosed with ≥ 4 ACR criteria. We included three study groups: group A included patients with SLE-associated TTP (TTP/SLE; cases n = 22, TTP events n = 24); patients with non-autoimmune TTP (NA-TTP; cases n = 19, TTP events n = 22) were included in group B and patients with SLE without TTP (n = 48) in group C.

RESULTS

After multivariate analysis, lymphopenia < 1000/mm3 [OR 19.84, p = 0.037], high SLEDAI score three months prior to hospitalisation [OR 1.54, p = 0.028], Hg <7g/dL [OR 6.81, p = 0.026], low levels of indirect bilirubin [OR 0.51, p = 0.007], and less severe thrombocytopenia [OR 0.98, p = 0.009] were associated with TTP in SLE patients. Patients with TTP/SLE received increased cumulative steroid dose vs. NA-TTP (p = 0.006) and a higher number of immunosuppressive drugs (p = 0.015). Patients with TTP/SLE had higher survival than NA-TTP (p=0.033); however, patients hospitalised for TTP/SLE had a higher risk of death than lupus patients hospitalised for other causes

CONCLUSIONS

Lymphopenia is an independent risk factor for TTP/SLE. It is likely that patients with TTP/SLE present with less evident clinical features, so the level of suspicion must be higher to avoid delay in treatment.

Gallbladder cancer-associated thrombotic microangiopathy

Cancer-associated thrombotic microangiopathy (TMA) is a rare but serious condition seen in patients diagnosed with malignancy. Certain tumor characteristics highlight this entity, such as large tumor burden, adenocarcinoma histology with mucinous features and bone marrow infiltration. Although these tumors may originate from any site, the majority are of stomach, breast or prostate origin. The optimal therapy is unknown but there is evidence that immediate initiation of an effective antineoplastic regimen is important. However, it is difficult to differentiate cancer-associated TMA from primary thrombotic thrombocytopenic purpura in a timely manner. We present the first case of cancer-associated TMA in a patient secondary to a locally advanced gallbladder adenocarcinoma that lacked mucinous features and bone marrow involvement. The clinical presentation closely mimicked primary thrombocytopenic purpura and led to the ineffective use of plasma exchange. Nonetheless, the patient eventually received systemic chemotherapy and had a remarkable response by the resolution of her TMA.

Inverse probability weighted estimating equations for randomized trials in transfusion medicine

Thrombocytopenia is a condition characterized by extremely low platelet counts, which puts patients at elevated risk of morbidity and mortality because of bleeding. Trials in transfusion medicine are routinely designed to assess the effect of experimental platelet products on patients' platelet counts. In such trials, patients may receive multiple platelet transfusions over a predefined period of treatment, and a response is available from each such administration. The resulting data comprised multiple responses per patient, and although it is natural to want to use this data in testing for treatment effects, naive analyses of the multiple responses can yield biased estimates of the probability of response and associated treatment effects. These biases arise because only subsets of the patients randomized contribute response data on the second and subsequent administrations of therapy and the balance between treatment groups with respect to potential confounding factors is lost. We discuss the design and analysis issues involved in this setting and make recommendations for the design of future platelet transfusion trials.

Unresponsive thrombotic thrombocytopenic purpura in critically ill adults

INTRODUCTION

The prognosis of thrombotic thrombocytopenic purpura (TTP) has considerably improved since the introduction of plasma exchange (PEX) therapy. However, unresponsive thrombotic thrombocytopenic purpura (Un-TTP) still carries high morbidity and mortality rates, indicating a need for early specific treatments.

PATIENTS AND METHODS

In a retrospective study including consecutive adults with TTP admitted between January 1997 and January 2011 in a teaching hospital intensive care unit (ICU), our objective here is to identify early clinical and laboratory features predicting Un-TTP. Patients who responded to plasma exchange and steroids (N = 49) were compared with patients with unresponsive TTP defined as requirement for other treatments, protracted course, or death (N = 37, 43 %).

RESULTS

Hospital mortality was 24.3 % in the Un-TTP group. Variables associated with Un-TTP on univariate logistic regression were older age, cardiac involvement, neurological involvement, higher anti-a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS13) immunoglobulin G (IgG) titer, lower platelet counts starting on day 2, higher Sequential Organ Failure Assessment (SOFA) scores starting on day 3, need for higher plasma volumes to obtain remission, and greater use of adjuvant treatments and life-sustaining interventions. Multivariate logistic regression identified four factors independently associated with Un-TTP: age over 60 years [odds ratio (OR) 7.90; 95 % confidence interval (95 % CI) 1.06-78.34], cardiac (OR 5.17; 95 % CI 1.63-16.39) or neurological (OR 8.04; 95 % CI 1.27-51.03) manifestations at diagnosis, and day 2 platelet count less than 15 G/l (OR 3.88; 95 % CI 1.30-11.62).

CONCLUSION

Therapeutic intensification starting on day 3 or even earlier in patients with the independent risk factors for unresponsive TTP identified in our study deserves evaluation in a multicenter prospective study.

Cyclosporin A therapy on idiopathic thrombotic thrombocytopenic purpura in the relapse setting: two case reports and a review of the literature

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease, characterized by microangiopathic hemolytic anemia, thrombocytopenia, fever, neurologic disturbances, and renal failure. Plasma therapy has dramatically improved prognosis of TTP, whereas recurrent acute episodes still occur in approximately 40% of patients. Moreover, patients with acquired ADAMTS13 deficiency, which is a significant factor for relapse, may require additional immunosuppressive treatment to get a durable remission.

STUDY DESIGN AND METHODS

We hereby report two patients with a history of relapsed idiopathic TTP, who both received cyclosporin A (CSA) as a prophylactic manner after the remission was achieved. We also discuss the efficacy of CSA in patients with relapsed idiopathic TTP with a review of the published literature.

RESULTS

Under CSA therapy, both patients maintained their clinical remission state, and the ADAMTS13 levels were normalized.

CONCLUSION

To conclude, CSA therapy may be useful for the prevention of relapsed idiopathic TTP in patients with a history of frequent relapses.

Acute kidney injury in patients with systemic sclerosis participating in hematopoietic cell transplantation trials in the United States

Recipients of hematopoietic cell transplantation may be at risk for developing acute kidney injury (AKI), and this risk may be increased in patients who undergo transplantation for severe systemic sclerosis (SSc) due to underlying scleroderma renal disease. AKI after transplantation can increase treatment-related mortality. To better define these risks, we analyzed 91 patients with SSc who were enrolled in 3 clinical trials in the United States of autologous or allogeneic hematopoietic cell transplantation (HCT). Eleven (12%) of the 91 patients with SSc in these studies (8 undergoing autologous HCT, 1 undergoing allogeneic HCT, 1 pretransplantation, 1 given i.v. cyclophosphamide on a transplantation trial) experienced AKI, of whom 8 required dialysis and/or therapeutic plasma exchange. AKI injury in the 9 HCT recipients developed a median of 35 days (range, 0-90 days) after transplantation. Ten of 11 patients with AKI received angiotensin-converting enzyme inhibitor (ACE-I) therapy. The etiology of AKI was attributed to scleroderma renal crisis in 6 patients (including 2 with normotensive renal crisis), to AKI of uncertain etiology in 2 patients, and to AKI superimposed on scleroderma kidney disease in 3 patients. Eight of the 11 patients died, one each because of progression of SSc, multiorgan failure, gastrointestinal and pulmonary bleeding, pericardial tamponade and pulmonary complications, diffuse alveolar hemorrhage, pulmonary embolism, graft-versus-host disease, and malignancy. Limiting nephrotoxins, cautious use of corticosteroids, renal shielding during total body irradiation, strict control of blood pressure, and aggressive use of ACE-Is may be of importance in preventing renal complications after HCT for SSc.

Komplexe Gerinnungsstörungen

Die thrombotisch-thrombozytopenische Purpura (TTP) und das hämolytischurämische Syndrom (HUS) sind thrombotische Mikroangiopathien, gekennzeichnet durch eine Endothelzellschädigung mit nachfolgender Bildung von Thromben in der Mikrozirkulation mit intravasaler Hämolyse und Thrombozytopenie. Ischämische Organdysfunktionen im Gehirn, den Nieren und anderen Organen Prägen das klinische Bild. Während bei Erwachsenen das Auftreten einer neurologischen Symptomatik zur Diagnose TTP führt, wird bei Kindern mit dem Leitsymptom Nierenversagen die Diagnose HUS gestellt.

A Canadian phase II study evaluating the efficacy of rituximab in the management of patients with relapsed/refractory thrombotic thrombocytopenic purpura

Rituximab is a chimeric monoclonal antibody that targets the human CD-20 antigen present on malignant and normal B lymphocytes. Recent clinical studies have shown a significant response rate when this drug is given to selected patients with thrombotic thrombocytopenic purpura (TTP). Given that the clinical manifestations of TTP may be the direct result of an auto-antibody against a regulatory Von Willebrand factor enzyme (ADAMTS13), it makes biological sense to consider a therapy that has the ability to diminish or eradicate antibody-producing B cells. Despite initial positive results, there is a need to identify which patients derive durable benefit from this agent. As in other conditions that utilize therapeutic immunosuppression, there is a risk that the addition of rituximab may also lead to serious opportunistic infections.

Thrombotic thrombocytopenic purpura related to severe ADAMTS13 deficiency in children

Thrombotic thrombocytopenic purpura (TTP) related to a severely deficient activity of the von Willebrand factor cleaving protease, ADAMTS (A Disintegrin And Metalloprotease with ThromboSpondin type 1 repeats) 13, is a life-threatening event, the onset of which may occur as early as childhood. TTP is either inherited (Upshaw-Schulman syndrome) via ADAMTS13 gene mutations (neonatal onset) or acquired via anti-ADAMTS13 autoantibodies (childhood onset). TTP is due to platelet- and von-Willebrand-factor-rich thrombi of the microvasculature, inducing mechanical hemolytic anemia, consumption thrombocytopenia, and multivisceral ischemia. Clinical course consists of relapsing acute events triggered mostly by infections, associated icterus and hyperbilirubinemia, severe hemolytic anemia with schistocytosis and a negative Coombs test, severe thrombocytopenia, and sometimes symptoms related to visceral ischemia (renal failure, central nervous system vascular events, other organ failure). The recently available ADAMTS13 laboratory investigation combining measurement of ADAMTS13 activity in plasma, search for an ADAMTS13 circulating inhibitor, and anti-ADAMTS13 IgG and ADAMTS13 gene sequencing is a crucial addition to TTP diagnosis. Plasma exchanges are first-line treatment of acquired TTP, combined with steroids and immunosuppressive drugs. Curative treatment of acute events in Upshaw-Schulman syndrome relies on plasma infusions (provider of active ADAMTS13). Guidelines for preventive treatment of relapses are not clearly established but should associate plasmatherapy and caution to triggers of relapses. Therapeutic perspectives are focused on the development of concentrated plasma-derived ADAMTS13 or recombinant ADAMTS13.

The Role Of von Willebrand Factor In Hemorrhagic And Thrombotic Disorders

von Willebrand factor (VWF) is a multimeric plasma protein that mediates platelet adhesion as well as platelet aggregation at sites of vascular injury and acts as a carrier of factor VIII. Although acquired or inherited VWF deficiency is associated with a bleeding tendency, there is increasing evidence that VWF has a pivotal role in thrombogenesis. In fact, while the presence in the plasma of unusually large VWF multimers, due to a congenital or acquired deficiency of a VWF-cleaving metalloprotease, has been implicated in the pathogenesis of thrombotic thrombocytopenic purpura, high plasma levels of VWF have been associated with an increased risk of both arterial and venous thrombosis. The role of VWF in normal and pathological hemostasis is discussed in this review, and important advances in the pathophysiology, diagnosis, and treatment of VWF-associated disorders are also described.

Thrombotic Thrombocytopenic Purpura in Humans and Mice

Thrombotic thrombocytopenic purpura (TTP) is a disorder of blood coagulation that presents classically with the pentad of fever, thrombocytopenia, microangiopathic hemolytic anemia, renal dysfunction and mental status changes. However, the clinical presentation can be quite variable making the diagnosis difficult in many cases. “Hyaline” microthrombi composed primarily of platelets and Von Willebrand Factor (VWF) are found in the small vessels of affected organs and represent the pathological hallmark of the disease. The accompanying tissue ischemia is thought to explain the clinical TTP signs and symptoms. Pathogenesis of TTP has been linked to dysfunction of ADAMTS13, a metalloprotease whose only known substrate is VWF. Interestingly, further investigation into the natural history of TTP has demonstrated that ADAMTS13 deficiency likely is necessary, but not sufficient for the development of this disease, suggesting that additional genetic and/or environmental factors are required for TTP pathogenesis. Recently, a mouse model of TTP was established that recapitulates many of the key clinical features of this disease, including the requirement for further genetic and environmental factors in addition to ADAMTS13 deficiency. Therefore, in addition to being useful for the direct study of disease pathophysiology in vivo , this mouse model may also play a key role in elucidating some of the important environmental and genetic contributors to disease pathogenesis. Here we will review TTP in humans, and then discuss recent information gained from the analysis of ADAMTS13-deficient mice.

Prognostic value of anti-ADAMTS 13 antibody features (Ig isotype, titer, and inhibitory effect) in a cohort of 35 adult French patients undergoing a first episode of thrombotic microangiopathy with undetectable ADAMTS 13 activity

To study both the pathophysiologic and the prognostic value of ADAMTS13 in thrombotic microangiopathies (TMAs), we enrolled a cohort of 35 adult patients combining a first acute episode of TMA, an undetectable (below 5%) ADAMTS13 activity in plasma, and no clinical background such as sepsis, cancer, HIV, and transplantation. All patients were treated by steroids and plasma exchange, and an 18-month follow-up was scheduled. Remission was obtained in 32 patients (91.4%), and 3 patients died (8.6%) after the first attack. At presentation, ADAMTS13 antigen was decreased in 32 patients (91.4%), an ADAMTS13 inhibitor was detectable in 31 patients (89%), and an anti-ADAMTS13 IgG/IgM/IgA was present in 33 patients (94%). The 3 decedent patients were characterized by the association of several anti-ADAMTS13 Ig isotypes, including very high IgA titers, while mortality was independent of the ADAMTS13 inhibitor titer. In survivors, ADAMTS13 activity in remission increased to levels above 15% in 19 patients (59%) but remained undetectable in 13 patients (41%). Six patients relapsed either once or twice (19%) during the follow-up. High levels of inhibitory anti-ADAMTS13 IgG at presentation were associated with the persistence of an undetectable ADAMTS13 activity in remission, the latter being predictive for relapses within an 18-month delay.

[Thrombotic microangiopathies. Incidence, pathogenesis, diagnosis, treatment and prognosis]

INTRODUCTION

The objective of this work was to review current data about the pathophysiology, clinical features, and treatment of thrombotic microangiopathies.

CURRENT KNOWLEDGE

Thrombotic microangiopathies are microvascular occlusive disorders characterized by systemic or intrarenal aggregation of platelets, thrombocytopenia, and mechanical injury to erythrocytes. In thrombotic thrombocytopenic purpura, systemic microvascular aggregation of platelets causes ischemia in the brain and other organs. In the hemolytic-uremic syndrome, platelet-fibrin thrombi occlude predominantly the renal circulation. Thrombotic microangiopathy is a rare disorder whose varied clinical manifestations result from the formation of platelet-rich thrombi within the microvasculature and consequent tissue ischemia. The clinical features are acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. This diagnosis is of considerable importance because of the possible fulminant clinical course. Some atypical forms may be unrecognized. Plasma exchange is the current reference treatment of thrombotic thrombocytopenic purpura. However, in the light of recent publications, either infusions of concentrates of purified enzyme or more intensive immunosuppressive therapy would be more specific.

Mycophenolate mofetil in a case of relapsed, refractory thrombotic thrombocytopenic purpura

A case of relapsing and refractory thrombotic thrombocytopenic purpura received mycophenolate mofetil (MMF) to attempt to maintain remission. The possible use of MMF in thrombotic thrombocytopenic purpura is discussed.

Management of cancer-associated thrombotic microangiopathy: what is the right approach?

A 49-year-old Caucasian woman presented with features suggestive of thrombotic microangiopathy (TMA). She did not respond to treatment with repeated plasma exchange and corticosteroids. A bone marrow biopsy revealed presence of metastatic carcinoma. A limited autopsy revealed presence of breast cancer with rib metastases. Though severe deficiency of von Willebrand factor-cleaving protease was initially proposed as a key pathogenetic factor for thrombotic thrombocytopenic purpura, subsequent studies involving patients with cancer-associated TMA did not find as severe a deficiency of von Willebrand factor-cleaving protease as is seen in idiopathic cases of thrombotic thrombocytopenic purpura. Here we address one approach of management of these patients with cancer-associated TMA.

Transplant-associated microangiopathy in patients receiving tacrolimus following allogeneic stem cell transplantation: risk factors and response to treatment

Transplant-associated microangiopathy (TAM) is a life-threatening complication after allogeneic HSCT, particularly with the use of calcineurin inhibitors as post-transplantation immunosuppressive therapy. We report our experience with TAM after HSCT with tacrolimus-based GVHD prophylaxis in a single-center study. Sixty-six of 1219 transplant recipients developed TAM with a cumulative incidence of 5.9%. Risk factors for TAM were female gender, lymphoid malignancy, receipt of a matched unrelated donor, and grade II-IV aGVHD. Most patients had infection and/or active GVHD at the diagnosis of TAM (82%). In the absence of renal dysfunction or encephalopathy, tacrolimus was generally continued, maintaining blood levels within the lower therapeutic range. Sixty-three patients were treated with plasma exchange. The cumulative incidence of response of TAM was 60%. Only 1 patient had a response of TAM without resolution of concomitant infections or GVHD. Six-month survivals were 0% and 50% for TAM nonresponders and responders, respectively. In conclusion, TAM is a common, life-threatening complication of allogeneic hematopoietic transplantation using tacrolimus prophylaxis. Control of TAM generally requires response of associated infections and GVHD. TMA response may occur despite continuation of tacrolimus treatment.

Therapeutic plasma exchange plus corticosteroid for the treatment of the thrombotic thrombocytopenic purpura: a single institutional experience in the southern Marmara region of Turkey

Thrombotic thrombocytopenic purpura (TTP) is a classic, but not a common disorder of hematology. Plasma exchange (PE) was shown to nearly reverse its 90% mortality rate. However, there are still some fatal outcomes in this dramatic disease. We present our experience of plasma exchange plus corticosteroids for the treatment of TTP in our hospital. Patients with TTP diagnosed between January 1996 and January 2005 were identified by a retrospective review of records of the Uludag University Hospital, Bursa (the largest referral center for adults with this disorder in this region with an estimated 2.2 million residents), which performs all therapeutic PE in the southern Marmara region in Turkey. A total of 11 (6 male, 5 female) patients were treated for TTP during this period. The median age was 39 years (range 18-49). One plasma volume exchange daily plus steroid was the principle treatment in all patients. A total of 295 PE sessions were performed. We have obtained six complete responses (CR) and three partial responses (PR) with daily PE and steroid (response rate 9/11). One of our primary refractory patients was saved with pulse steroid+cyclosporine+vincristine. Now, he is disease free for over one year. The other refractory patient did not develop any response to salvage therapy and expired on day 15 with status epilepticus and ventilator related pneumonia (mortality rate 1/11). A CR was obtained with adjuvant treatments in all three PR patients. Only one CR patient developed an early relapse (early relapse rate in CR patients 1/6). She was treated successfully with daily PE plus vincristine. Our median follow up period was 25 months (range 9-108). Considering our local population, our annual incidence is only about 0.63 new cases per one million people. This figure is considerably less than the data from US, which indicated an incidence of 3.7 cases per 1,000,000. To our knowledge, there is no high variability in the incidence of TTP in the different geographical regions of the world. It suggests that considerable number of patients escaped notice. We hope that, demonstrating the successful outcome, this article serves to urge primary physicians to keep in mind the diagnosis of TTP and refer suspected cases quickly.

Identification of plasma antifibrin/fibrinogen antibodies in a patient with hemolytic uremic syndrome

We investigated a patient with atypical hemolytic uremic syndrome without diarrhea to determine the presence of antibodies and the specificity of the related antigens. The patient experienced repeated episodes of hemolytic uremic syndrome. She is dialysis dependent. von Willebrand factor (vWF), vWF multimers, platelet aggregation, ADAMTS-13 activity and platelet immunoblots were determined. During acute episodes vWF increased threefold, with unusually large vWF multimers on two occasions. Platelet aggregation was normal but the plasma caused spontaneous aggregation of normal platelets. Reactivity was removed after absorption with protein A. Protein blotting against platelet and microvascular endothelial cells showed strong and persistent reactivity against antigens of 200 and 55 kDa. Two-dimensional immunoblots of the whole platelet proteome and incubation with plasma identified strong immunoreactivity with two target spots in the 55-kDa area. Mass spectroscopy confirmed the target as beta-fibrin, molecular weight 50.73 kDa, isoelectric point 7.95, with MASCOT scores of 859 and 750, Two years after presentation another band was detected at 66 kDa and identified as the alpha subunit of fibrin. This patient's plasma contained a platelet-aggregating factor that was removed by immunoglobulin absorption. She developed antibodies against the alpha and beta subunits of fibrin/fibrinogen.

Les microangiopathies thrombotiques en réanimation

OBJECTIVES

To analyze the clinico-biological manifestations, identify the causes and evaluate the outcome of patients with severe thrombotic microangiopathies admitted in a Tunisian intensive care unit.

METHODS

Retrospective study over a period of 10 years (1995-2004) in an intensive care unit.

RESULTS

Were included in this study 9 cases with a mean age of 29.2+/-9 years (range 15-44 years). Fever was observed in 5 patients, neurological impairment in 5 and digestive manifestations in 6. Haemolytic anaemia, thrombocytopenia and acute renal failure were observed in 100% of the cases. In our study, the aetiologies of thrombotic microangiopathies were: complicated pregnancy in 6 cases, systemic lupus erythematosus in 1 case. In contrast, no aetiology was found in 2 patients. Plasma exchange was performed in 5 patients, while 4 patients received only plasma infusion. After an average stay of 18+/-12.5 days, evolution was marked by the death 3 patients.

CONCLUSION

The incidence of severe thrombotic microangiopathies is rare in Tunisian ICU. The clinical manifestations are not specific. Despite the improvement in the outcome by exogenous plasma supply, thrombotic microangiopathies with severe organ dysfunctions leading to hospitalization in the intensive care unit are associated with a high mortality rate.

Thrombotic Thrombocytopenic Purpura: aetiology, pathophysiology and treatment

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder whose varied clinical manifestations result from the formation of platelet-rich thrombi within the microvasculature and consequent tissue ischaemia. This review will outline how, in the eighty years since its initial description, scientific discoveries have not only led to a deeper understanding of the fundamental pathophysiology of TTP, but have also contributed to advances in the clinical management of this condition. Current research in this field will hopefully provide the basis for the design and development of novel therapeutic strategies.

Thrombotic thrombocytopenic purpura

This overview summarizes the history of thrombotic thrombocytopenic purpura (TTP) from its initial recognition in 1924 as a most often fatal disease to the discovery in 1997 of ADAMTS-13 deficiency as a major risk factor for acute disease manifestation. The cloning of the metalloprotease, ADAMTS-13, an essential regulator of the extremely adhesive unusually large von Willebrand factor (VWF) multimers secreted by endothelial cells, as well as ADAMTS-13 structure and function are reviewed. The complex, initially devised assays for ADAMTS-13 activity and the possible limitations of static in vitro assays are described. A new, simple assay using a recombinant 73-amino acid VWF peptide as substrate will hopefully be useful. Hereditary TTP caused by homozygous or double heterozygous ADAMTS-13 mutations and the nature of the mutations so far identified are discussed. Recognition of this condition by clinicians is of utmost importance, because it can be easily treated and--if untreated--frequently results in death. Acquired TTP is often but not always associated with severe, autoantibody-mediated ADAMTS-13 deficiency. The pathogenesis of cases without severe deficiency of the VWF-cleaving protease remains unknown, affected patients cannot be distinguished clinically from those with severely decreased ADAMTS-13 activity. Survivors of acute TTP, especially those with autoantibody-induced ADAMTS-13 deficiency, are at a high risk for relapse, as are patients with hereditary TTP. Patients with thrombotic microangiopathies (TMA) associated with hematopoietic stem cell transplantation, neo-plasia and several drugs, usually have normal or only moderately reduced ADAMTS-13 activity, with the exception of ticlopidine-induced TMA. Diarrhea-positive-hemolytic uremic syndrome (D+ HUS), mainly occurring in children is due to enterohemorrhagic Escherichia coli infection, and cases with atypical, D- HUS may be associated with factor H abnormalities. Treatment of acquired idiopathic TTP involves plasma exchange with fresh frozen plasma (FFP), and probably immunosuppression with corticosteroids is indicated. We believe that, at present, patients without severe acquired ADAMTS-13 deficiency should be treated with plasma exchange as well, until better strategies become available. Constitutional TTP can be treated by simple FFP infusion that rapidly reverses acute disease and--given prophylactically every 2-3 weeks--prevents relapses. There remains a large research agenda to improve diagnosis of TMA, gain further insight into the pathophysiology of the various TMA and to improve and possibly tailor the management of affected patients.

The quality of fresh-frozen plasma produced from whole blood stored at 4°C overnight

BACKGROUND

The aim of this study was to assess whether the quality of FFP produced from whole blood stored at 4 degrees C overnight is adequate for its intended purpose.

STUDY DESIGN AND METHODS

Fresh-frozen plasma (FFP) separated from whole blood (n = 60) leukodepleted (LD) after storage at 4 degrees C overnight (18-24 hr from donation, Day 1 FFP) was compared with that LD within 8 hours of donation (Day 0 FFP, the current standard method).

RESULTS

In more than 95 percent of Day 1 FFP units, levels of factor (F) II, FV, FVII, FVIII, F IX, FX, FXI, and FXII were greater than 0.50 U per mL except for von Willebrand factor (VWF) antigen and FVIII, where 92 and 87 percent of units, respectively, contained greater than 0.50 IU per mL. Compared with historical data on FFP stored for 8 hours, fibrinogen, FV, FVIII, and FXI were reduced by 12, 15, 23, and 7 percent, respectively, but other factors were not significantly reduced. Levels of VWF-cleaving protease activity were not different between FFP prepared from paired units of blood (n = 3) held for 8 or 24 hours, but were below the reference range in an additional 2 of 6 units held for 24 hours. The activities of protein S, protein C, antithrombin III, and alpha(2)-antiplasmin were reduced by less than 10 percent in Day 1 FFP (n = 20), but with final levels above the lower limit of the normal range in greater than 95 percent of units. Activated FXII antigen was not significantly raised in plasma stored for 18 to 24 hours, but levels of prothrombin fragment 1 + 2 were slightly increased (0.88 ng/mL, 18-24 hr; 0.65 ng/mL, < 8 hr).

CONCLUSION

These data suggest that there is good retention of relevant coagulation factor activity in plasma produced from whole blood stored at 4 degrees C for 18 to 24 hours and that this would be an acceptable product for most patients requiring FFP.

ADAMTS13 turns 3

It has now been 3 years since the von Willebrand factor (VWF)–cleaving protease implicated in thrombocytopenic purpura (TTP) pathogenesis was identified as ADAMTS13 (adisintegrin-like and metalloprotease with thrombospondin type 1 motif 13). More than 50 ADAMTS13 mutations resulting in familial TTP have been reported. Considerable progress has also been realized toward understanding the role of ADAMTS13 in normal hemostasis, as well as the mechanisms by which ADAMTS13 deficiency contributes to TTP pathogenesis. Measurement of ADAMTS13 activity in TTP and other pathologic conditions also remains a focus of a substantial clinical research effort. Building on these studies, continued investigation of ADAMTS13 and VWF holds considerable promise for advancing the understanding of TTP pathogenesis and should lead to improved diagnosis and treatment for this important hematologic disease.

Thrombotic thrombocytopenic purpura in the setting of systemic sclerosis

OBJECTIVES

To describe the association between thrombotic thrombocytopenic purpura (TTP) and systemic sclerosis (SSc) and the methods to distinguish TTP from scleroderma renal crisis (SRC).

METHODS

A case of TTP that developed in a patient with preexisting SSc is described. Medline/PubMed was searched for literature pertaining to an association between TTP and SSc, with special attention given to distinguishing TTP from SRC. In addition, the role of von Willebrand cleaving protease in the pathogenesis of TTP is reviewed.

RESULTS

Including the present case, there have been 9 reports of TTP in association with SSc in the literature. In the majority of these cases TTP presented with features compatible with SRC such as renal dysfunction, thrombocytopenia, hypertension, and microangiopathic hemolytic anemia. Von Willebrand cleaving protease activity is depressed in patients with acute TTP.

CONCLUSIONS

TTP in association with SSc has been reported rarely. The diagnosis of TTP, and the distinction from SRC, may be challenging, as these cases may resemble SRC. However, the correct diagnosis is critical because treatment differs substantially for each of these life-threatening conditions. Currently, the assessment of von Willebrand factor cleaving protease activity may assist in making this distinction.

Thrombotic thrombocytopenic purpura without schistocytes on the peripheral blood smear

A hallmark of the clinical syndrome of thrombotic thrombocytopenic purpura (TTP) is evidence of microangiopathic hemolytic anemia. The presence of schistocytes on the peripheral blood smear, elevated plasma lactic dehydrogenase, and decreased haptoglobin concentration are used as evidence of microangiopathic hemolytic anemia to make a diagnosis of TTP. This report describes a case of recurrence of TTP in the absence of schistocytes in the peripheral blood smear during the recurrent episode. Although careful attention should be paid to microscopic examination of a blood smear in any patient presenting with acute renal failure and thrombocytopenia, this case emphasizes the need to consider TTP-hemolytic uremic syndrome in the differential diagnosis, even in the absence of peripheral schistocytosis.

Combination vincristine and plasma exchange as initial therapy in patients with thrombotic thrombocytopenic purpura: one institution's experience and review of the literature

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) was once a highly fatal disease with mortality reaching nearly 95 percent; however, application of therapeutic plasma exchange (TPE) has dramatically increased survival. Nevertheless, mortality remains substantial (10%-30% in many published reports), requiring the search for more efficacious treatments. Vincristine (VCR) has been generally reserved for refractory TTP. Despite its effectiveness in a salvage mode, VCR has not been widely advocated as first-line therapy in conjunction with TPE. We previously reported improved survival when VCR and TPE were administered at presentation in patients treated from 1979 to 1994. Utilizing this standardized approach, outcomes of an additional group of patients and the results of a literature review of VCR therapy for TTP are reported.

STUDY DESIGN AND METHODS

Medical records of all patients with a diagnosis of TTP treated between 1995 and 2002 at Cedars-Sinai Medical Center were reviewed. TPE was performed daily, exchanging 1.25 plasma volumes, until the platelet count normalized. Patients received VCR 1.4 mg/m2, (up to 2.0 mg total dose) after the first TPE. A literature review of all publications utilizing VCR in the management of TTP was performed with MEDLINE.

RESULTS

Twelve consecutive patients meeting the diagnostic criteria received treatment with VCR and TPE. All patients achieved durable remission. Patients tolerated VCR without significant complications.

CONCLUSION

Our 100 percent survival rate, as well as evidence garnered from the literature review, suggests that combination therapy with VCR and TPE at presentation might be more effective than TPE alone and therefore warrants consideration as first-line therapy for TTP patients.

Thrombotic thrombocytopenic purpura in patients with retroviral infection is highly responsive to plasma infusion therapy

We prospectively studied presentation biological differences and the response to therapy in patients with thrombotic thrombocytopenic purpura (TTP) associated with, or unrelated to human immunodeficiency virus (HIV) infection. TTP patients underwent standard evaluations and were treated with prednisone 1 mg/kg in addition to infusions of fresh frozen plasma (FFP; 30 ml/kg/d) until normalization of the platelet count. Unresponsive patients were referred for plasma exchange. Compared with HIV- TTP patients (n=23), in HIV+ subjects (n=21) microangiopathy was dominant among Black females, who had lower presentation Hb (median 5.8 g/dl; P=0.03), platelet count (13 x 10(9)/l; P=0.05) and a CD4 count of 0.096 x 10(9)/l. HIV+ individuals responded to FFP faster than HIV- patients and none of them required apheresis. Ten HIV- TTP patients required apheresis (P=0.03) and four died. Responses in the HIV+ and HIV- groups occurred after treatment with a median of 33 and 55 units (one unit=320 ml) of FFP (P=0.004) respectively. Response to this protocol was seen in 84% (95% response in HIV+ patients). Regression analysis showed that survival was associated with younger age (P=0.001), rapid platelet (P=0.001) and Hb (P=0.0009) recovery, and fewer FFP units to normal lactate dehydrogenase levels (P=0.006). We conclude that in HIV+ individuals, microangiopathy is highly responsive to plasma infusions. This observation is important particularly when apheresis is not available.