The changing course of thrombotic thrombocytopenic purpura and modern therapy

A Saudi multicenter experience on therapeutic plasma exchange for patients with thrombotic thrombocytopenic purpura: A call for national registry

BACKGROUND

The improvement in the clinical care for patients with thrombotic thrombocytopenic purpura (TTP) is evolving, and many efforts are being put to standardize it. Here, we aimed to assess the provided care at a national level and identify deficiencies.

METHODS

A national Saudi retrospective descriptive study was carried out at six tertiary referral centers and included all patients who underwent therapeutic plasma exchange (TPE) for the diagnosis of TTP between May 2005, and July 2022. Collected information included demographic data, clinical features on presentation, and the results of laboratory investigations at admission and discharge. In addition, the number of TPE sessions, days till the first session of TPE, usage of immunological agents, and clinical outcomes were all collected.

RESULTS

One hundred patients were enrolled, predominantly female (56%). The mean age was 36.8 years. At diagnosis, 53% of patients showed neurological involvement. The mean platelet count at presentation was 21 × 109 /L. All patients had anemia (mean hematocrit 24.2%). Schistocytes were present in the peripheral blood film of all patients. The mean number of TPE rounds was 13 ± 9.3, and the mean days to start TPE since admission for the first episode was 2.5 days. ADAMTS13 level was measured in 48% of patients and was significantly low in 77% of them. Assessing for clinical TTP scores, 83%, 1000%, 64% of eligible patients had an intermediate/high PLASMIC, FRENCH, and Bentley scores, respectively. Caplacizumab was used on only one patient, and rituximab was administered to 37% of patients. A complete response for the first episode was achieved in 78% of patients. The overall mortality rate was 25%. Neither time to TPE, the use of rituximab or steroid affected survival.

CONCLUSIONS

Our study shows an excellent response to TPE with a survival rate approximate to the reported international literature. We observed a deficiency in using validated scoring systems in addition to confirming the disease by ADAMTS13 testing. This emphasizes the need for a national registry to facilitate proper diagnosis and management of this rare disorder.

ADAMTS13 Autoantibodies and Burden of Care in Immune Thrombotic Thrombocytopenic purpura: New Evidence and Future Implications

The introduction Caplacizumab in the management of Immune thrombotic thrombocytopenic purpura (iTTP) has raised different questions, considering its cost-efficacy and the optimal immunosuppressive treatment (IST) to associate. A retrospective multicenter collection of 42 first iTTP cases was conducted to identify variables associated with a higher burden of care and necessity of an implemented IST with early Rituximab (RTX) rescue. A significant correlation resulted between ADAMTS13 inhibitors (ADAMTS13inh) at diagnosis with total plasma exchange (PEXtot) and PEX needed to achieve clinical response (PEXtoCR, r = 0.46; r = 0.48), along with age (r = - 0.31; r = -0.35), platelet count (r = -0.30; r = -0.30), LDH (r = 0.44; r = 0.41) and total bilirubin (r = 0.54; r = 0.35). ADAMTS13inh also correlated with number of days of hospitalization (DoH, r = 0.44). A significant difference was observed in terms of median ADAMTS13inh titer at diagnosis in patient treated with RTX rescue and those responding to only steroid treatment. Thus, ADAMTS13inh titer resulted a marker of iTTP burden of care, associated with higher number of PEXtot, PEXtoCR, DoH and higher probability of needing RTX rescue to achieve clinical response and could be a useful tool for management of new iTTP cases and an interesting variable to optimize iTTP cases stratification in future Caplacizumab cost-efficacy analysis.

The clinical and laboratory features of Chinese Han anti-factor H autoantibody-associated hemolytic uremic syndrome

BACKGROUND

Anti-complement factor H (CFH) autoantibody-associated hemolytic uremic syndrome (HUS) is a severe sub-type of HUS.

METHODS

We assessed the clinical and renal pathological features, circulating complement levels, and genetic background of Chinese pediatric patients with this sub-type of HUS. Thirty-three consecutive patients with acute kidney injury who tested positive for serum anti-CFH autoantibodies were enrolled in this study.

RESULTS

All of the eight patients who underwent renal biopsies presented with changes typical of thrombotic microangiopathy, especially changes in chronic characteristics. Compared to patients in remission and normal control subjects, patients with acute disease had significantly lower plasma CFH levels and significantly higher plasma complement 3a (C3a), C5a, and terminal complement complex (SC5b-9) levels. The CFH-anti-CFH immunoglobin G (IgG) circulating immunocomplex (CFH-CIC) titers were more closely correlated with CFH plasma levels than anti-CFH IgG levels. Of the 22 patients, four (18%) were homozygous for CFHR3-1Δ and ten were heterozygous for CFHR1 or CFHR3 deletions. Most patients responded well to a combination of plasma and immunosuppressive therapies, with a remission rate of 87%. At the end of the follow-up, nine patients reached the combined end-points, including two with end-stage renal disease and seven with relapses.

CONCLUSION

Plasma C3a, C5a, and SC5b-9 levels predicted disease activity in anti-CFH autoantibody-associated HUS patients enrolled in this study. These patients responded well to plasma therapy combined with immunosuppression.

Clopidogrel-Associated Thrombotic Thrombocytopenic Purpura following Endovascular Treatment of Spontaneous Carotid Artery Dissection

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening multisystem disease secondary to platelet aggregation. We present a patient who developed profound thrombocytopenia and anemia 8 days following initiation of therapy with clopidogrel after stent placement for carotid artery dissection. She did not have a disintegrin and metalloproteinase with thrombospondin domain 13 (ADAMTS 13) deficiency. Management included steroids and therapeutic plasma exchange. Clopidogrel has rarely been associated with TTP. Unlike other causes of acquired TTP, the diagnosis of early clopidogrel-associated TTP is largely clinical given the infrequent reduction in ADAMTS 13 activity.

Clinical and renal biopsy findings predicting outcome in renal thrombotic microangiopathy: a large cohort study from a single institute in China

Objective. The current study aimed to investigate the spectrum of etiologies and associated disorders of renal biopsy-proven thrombotic microangiopathy (TMA) patients. Methods. The clinical, laboratory, and renal histopathological data of patients with renal TMA from 2000 to 2012 in our institute were collected and reviewed. Results. One hundred and nine TMA patients were enrolled in this study. The mean age was 34.0 ± 11.1 years. Seventy patients (64.2%) were male and thirty-nine patients (35.8%) were female. There were eight patients (7.3%) with hemolytic uremic syndrome (HUS). Sixty-one patients (56.0%) were secondary to malignant hypertension. Fourteen patients (12.8%) were pregnancy-associated TMA. Other associated disorders included 17 patients with connective tissue disorders, 2 patients with hematopoietic stem cell transplantation, 4 patients with Castleman's disease, 1 patient with cryoglobulinemia, and 2 patients with glomerulopathy. During followup, 8 patients died due to severe infection, 17 patients had doubling of serum creatinine, and 44 had end-stage renal disease. In multivariate analysis, male, elevated serum creatinine, and decreased hemoglobin were independently associated with poor renal outcomes. Conclusions. Renal TMA changes consisted of different disorders with various etiologies. aHUS, pregnancy-associated TMA, and malignant hypertension accounted for the majority of patients in our cohort.

Tacrolimus-induced thrombotic microangiopathy in orthotopic liver transplant patients: case series of four patients

Thrombotic microangiopathy (TMA) is a potentially fatal complication in solid organ and bone marrow transplant patients, with reported incidence of 0.5-3% and mortality of about 75%. To emphasise the importance of early diagnosis and prompt commencement of therapy results in improved clinical outcomes. A retrospective study of all patients who underwent orthotopic liver transplantation (OLTX) at the Western Australian Liver Transplantation Service from May 1994 to December 2010 was conducted to identify patients who developed tacrolimus-induced TMA. We identified four patients with tacrolimus-induced TMA post-OLTX, derived from a cohort of 104 patients treated with tacrolimus in our institution. The mean age at diagnosis was 40 years, and the mean time of onset was 63 ± 7.5 weeks after OLTX. The indications for OLTX in the four patients were fulminant hepatic failure in three (Wilson disease, paracetamol overdose and post-partum thrombotic thrombocytopenic purpura) and hepatitis C virus-related cirrhosis. All patients had tacrolimus post-OLTX. At diagnosis, tacrolimus was discontinued in all patients, and three of the four patients underwent plasma exchange and all patients improved clinically. Mean duration of follow up was 15 ± 7.5 months. There was no mortality 6 months post-TMA. Early diagnosis with immediate discontinuation or conversion of calcineurin inhibitors and plasma exchange should be offered to OLTX patients with TMA as it results in good outcomes.

Thrombotic thrombocytopenic purpura: A single - Centre experience

We aimed to describe the characteristics, treatment regime, and 6-month all-cause mortality of thrombotic thrombocytopenic purpura (TTP) patients treated with total plasma exchange in the our clinic. Thirteen patients were included in the study. Mortality rates of TTP have improved over the last three decades but they are still too high according to modern therapy expectations. Etiology directed treatment should be added to total plasma exchange in secondary TTP cases. Based on TTPs' immunologic etiology, immune modulator and immune suppressor agents have been applied together with total plasma exchange, but mostly in anecdotal case reports or with questionable responses.

TTP/HUS: observational studies generate hypotheses that lead to randomized controlled trials

Thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) is a disease syndrome, and its history exemplifies how small observational studies lead to hypotheses that spawn randomized control trials (RCTs). Moschowitz's original case report coupled with the case findings of Bukowski and Byrne led to the RCT of Rock and the Canadian Apheresis Group that proved plasma exchange was superior to plasma infusion for the treatment of adults with TTP/HUS. Our single case report of continuous plasma exchange coupled with the observations about the pathogenic role of von Willebrand multimer protease of Tsai and Furlan strengthened by a 25-year observational study of plasma exchange treatment for TTP/HUS has led to a proposal to initiate a new RCT.

Treating TTP/HUS with plasma exchange: a single centre's 25-year experience

Thrombotic thrombocytopenic purpura/Haemolytic uremic syndrome (TTP/HUS) is a thrombotic microangiopathy with a 6-month mortality rate of 16-29%. The present study described the clinical features, treatment regime and 6-month all-cause mortality rate of TTP/HUS patients at the London Health Sciences Centre (LHSC), Canada. Data for this retrospective cohort study were obtained from inpatient and outpatient records for all patients referred for plasma exchange therapy at LHSC, Canada between 1981 and 2006. Patients (n = 110) were categorized as: idiopathic primary (38%) or relapsed (16%), and secondary responsive (30%) or non-responsive (16%). Mortality data were available for all but three patients. The all-cause 6-month mortality rate was 19% overall and was 12% and 26% among idiopathic and secondary TTP/HUS patients, respectively. No mortality events occurred among the 17 idiopathic patients who relapsed. Relapsed patients had the least severe presenting characteristics, the fastest response time, and experienced significant improvement in the severity of clinical features between the first and final presentation. These findings suggest an excellent outcome for relapsed TTP/HUS patients. Patient education, surveillance, and aggressive plasma exchange therapy are hypothesized to improve the likelihood of survival: these hypotheses should be tested in a randomized controlled trial.

[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.

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/haemolytic uraemic syndrome: a new index predicting response to plasma exchange

Despite the favourable response of thrombotic thrombocytopenic purpura/haemolytic uraemic syndrome (TTP/HUS) to plasma exchange, an early level of mortality persists. Non-response has been associated with a low frequency of exchange. The Rose index of TTP/HUS severity, occasionally used to predict the response of TTP/HUS to plasma exchange, remains unsatisfactory. The purpose of this study was to develop a new index predicting response of TTP/HUS to plasma exchange and to compare it with the Rose index. Retrospective analysis of 171 cases of TTP/HUS from 39 apheresis units across Canada between 1980 and 2001 was conducted. Logistic regression analysis was used to derive a model predicting 6-month mortality from presenting characteristics. The reduced model contained age >40 years, haemoglobin <9.0 g/dl and the presence of a fever at presentation. Gender, platelet count, creatinine and neurological signs were not part of the final model. This model predicted 13.4% of outcome variance. Predictive scores of 0, 2, 4 and 6 correlated with 6-month mortality rates of 12.5%, 14.0%, 31.3% and 61.5% respectively in our source population. This simple model may help identify those patients who would benefit from higher treatment intensity.

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.

A case study of thrombotic thrombocytopaenic purpura: a 'powerful poison'

This paper presents the case of a previously well 72 year old man who spent 86 days in the intensive care unit (ICU) following a remarkable and explosive presentation of the rare condition thrombotic thrombocytopaenic purpura (TTP). TTP is an intravascular platelet aggregation disorder that, without treatment, is associated with significantly high mortality rates. This paper discusses TTP in terms of its presentation, pathophysiology, diagnosis and management. In addition to TTP, the patient developed a number of comorbidities during his stay in ICU. Particular attention is given to two major problems: acute renal failure and prolonged encephalopathy. These issues, along with the initial diagnosis of TTP, resulted in the patient remaining in ICU for a longer period than otherwise might have been expected. Despite many obstacles, the patient recovered and was discharged from hospital 116 days after initial presentation.

Cryoprecipitate poor plasma does not improve early response in primary adult thrombotic thrombocytopenic purpura (TTP)

Thrombotic thrombocytopenic purpura (TTP) is a potentially fatal disease that is treated with plasma exchange and typically with replacement with fresh frozen plasma (FFP). This approach results in an approximate 50% response rate following 1 week of therapy and 80% survival. Cryoprecipitate poor plasma (CPP) is plasma from which the cryoprecipitate fraction is removed. CPP has been reported to be successful as salvage therapy in refractory TTP and has been suggested to be superior to FFP in retrospective studies. The present report compares initial therapy of TTP with exchange using replacement with either FFP or CPP in a multi-institutional prospective randomized study performed by the North American TTP Group (NATG Group) from 1993 to 1995. Initial therapy also included corticosteroids. Antiplatelet drugs or vinca alkaloids were not employed. A severity score index, response score, and individual clinical parameters (platelet count, LDH x upper limit of normal, hemoglobin level, and creatinine) were compared at their nadir or peak values, baseline, and days +6 and +13 of therapy. Thirteen patients were randomized to FFP exchange and 14 to CPP exchange. Results were equivalent for all parameters. Survival was equal with three deaths in each group. These data indicate that the efficacy of FFP and CPP are the same in the initial treatment of TTP in adults.

The management of idiopathic thrombotic microangiopathy. Changing trends

Thrombotic microangiopathy, including the two related syndromes thrombotic thrombocytopenic purpura and hemolytic-uremic syndrome, is a rare and severe multisystem disorder, due to widespread deposition of intravascular microthrombi consisting mainly of platelets, with subsequent consumption thrombocytopenia, microangiopathic hemolytic anemia, renal abnormalities, and neurologic disturbances. The epidemic, verotoxin-induced hemolytic-uremic syndrome, typically associated with prodromal diarrhea, mainly affects young children in small outbreaks. By contrast, idiopathic thrombotic microangiopathy generally affects adults in a sporadic form; it has a more devastating course and a less favourable outcome. Over 90% of the reported cases in the adult, when untreated, have progressed to death within three months of diagnosis. Since the introduction of plasma exchange, a dramatic change in the prognosis of the disease has taken place, although the mortality rate still remains considerable. Indeed, improved survival is the most striking feature of adult thrombotic microangiopathy compared to some decades ago. In the present article we will focus on the evolving concepts able to exert a considerable impact in the management of the adult idiopathic form of thrombotic microangiopathy.

[Idiopathic thrombotic thrombocytopenic purpura or Moschowitz syndrome: current physiopathologic and therapeutic perspectives]

INTRODUCTION

The objective of this work was to review current data about the physiopathology, clinical features, and treatment of thrombotic thrombocytopenic purpura (Moschowitz's syndrome).

CURRENT KNOWLEDGE AND KEY POINTS

Thrombotic thrombocytopenic purpura is a rare disorder characterized by widespread thrombotic injuries of platelets in the microcirculation. Its physiopathology has been elucidated recently. Evidence of a deficiency of Von Willebrand's factor-cleaving protease would be due to either IgG antibodies in the acute form of the disease or constitutional deficiency in the chronic form of the disease.

FUTURE PROSPECTS AND PROJECTS

Plasma exchange is the current reference treatment. However, in the light of recent publications, either infusions of concentrates of purified enzyme or more intensive immunosuppressive therapy would be more specific.

Serum concentrations of laminin-P1 in thrombotic microangiopathy: usefulness as an index of activity and prognostic value

Laminin is the main noncollagenous constituent of the basement membrane, and its serum levels could reflect the metabolic changes that occur in the basement membrane. Severe endothelial injury with thickening of basement membrane is a characteristic feature of thrombotic microangiopathy (TMA). With this background, the aim of the study was to investigate in a prospective way (1) the relationship among serum Lam-P1, the extent of renal histopathologic lesions, and the biochemical parameters commonly used as markers of TMA activity, and (2) the usefulness of serum Lam-P1 concentrations as a renal outcome prognostic index. To this end, 18 consecutive patients with active biopsy-proven TMA with renal involvement were studied. One hundred and twenty-one healthy control subjects, 20 patients with systemic scleroderma without renal involvement, and 35 patients with systemic lupus erythematosus (20 without nephropathy and 15 with diffuse proliferative type 4 lupus nephritis) were used as control groups. In addition, to analyze the influence of either renal failure or hemodialysis therapy on serum Lam-P1 levels, 91 patients on regular hemodialysis therapy and 81 patients with predialysis chronic renal failure of different etiologies were included in the study. Serum Lam-P1 was determined by RIA at admission, on days 10 and 30 of follow-up in all patients, and after 6 and 12 mo of follow-up in all surviving patients. Serum lactate dehydrogenase, haptoglobin, platelet count, hemoglobin, and serum creatinine were determined as markers of endothelial dysfunction and hemolysis. At admission, serum levels of Lam-P1 were significantly higher in patients with TMA than in healthy control subjects (3.39 +/- 0.56 U/ml versus 1.40 +/- 0.18 U/ml; P < 0.0001). In addition, patients with TMA had significantly higher serum Lam-P1 levels than the other groups included in the study. At the first control, Lam-P1 correlated with lactate dehydrogenase (P = 0.006) and hemoglobin (P = 0.002). During follow-up, platelet count and hemolysis indicators normalized in all patients, while serum Lam-P1 decreased only in patients with renal function recovery. In multivariate analysis, serum creatinine and Lam-P1 at day 10 were the only independent predictors of renal outcome (r2 = 0.94; P < 0.0001) and also correlated with indices of histopathologic damage (P < 0.001). Serum Lam-P1 normalized in all patients with chronic renal failure in the samples obtained at 6 and 12 mo of regular hemodialysis after solving active TMA, thus suggesting that histopathologic lesions, but not renal function itself, would be mainly responsible for the high Lam-P1 serum concentrations detected in TMA. In conclusion, serum Lam-P1 concentrations are increased in patients with active TMA. Furthermore, patients with poor renal outcome show a prolonged increase of serum Lam-P1 that is related to the extent of renal histologic lesions. Unlike the biochemical markers of hemolysis commonly used to assess TMA activity, the sequential determination of serum Lam-P1 provides valuable information about long-term renal prognosis in patients with TMA.

Close relationship between systemic lupus erythematosus and thrombotic thrombocytopenic purpura in childhood

OBJECTIVE

To determine the association between childhood-onset thrombotic thrombocytopenic purpura (TTP) and systemic lupus erythematosus (SLE).

METHODS

The charts of all 5 patients diagnosed with idiopathic TTP at the Hospital for Sick Children (HSC) in Toronto from 1975 to 1998, and all cases of childhood-onset TTP (ages 6-20 years) reported in the literature over the same period were reviewed. Fourteen of the 44 patients identified in the literature were excluded from the analysis for lack of clinical and laboratory information. The remaining 35 patients were grouped into either an SLE/TTP group or a TTP only group, according to the presence or absence of the American College of Rheumatology (ACR) classification criteria for SLE. The groups were compared for differences in clinical or laboratory features.

RESULTS

The clinical presentation and initial disease course of pediatric patients with TTP were similar to those observed in adults. Of the 35 patients with childhood-onset TTP included in this review, 9 (26%) fulfilled > or = 4 ACR criteria for SLE and 8 (23%) were found to have incipient SLE. Of the 5 patients initially diagnosed with idiopathic TTP at the HSC, 3 were diagnosed with SLE within 3 years, and the other 2 patients fulfilled 3 ACR classification criteria for SLE within 4 years of disease onset. The clinical syndrome of pediatric TTP presenting with proteinuria, especially with high-grade proteinuria, was significantly associated with the development or coexistence of childhood-onset SLE.

CONCLUSION

TTP in childhood is a rare, but life-threatening, disease. Unlike in adults, TTP in childhood is commonly associated with SLE. High-grade proteinuria at diagnosis of TTP is the best predictor for the presence or subsequent development of SLE.

Treatment of thrombotic thrombocytopenic purpura with the cryosupernatant fraction of plasma: a case report and review of the literature

We report a case of thrombotic thrombocytopenic purpura (TTP) that did not respond to extensive plasma exchange with fresh frozen plasma (FFP) but responded to plasma exchange with cryosupernatant. Several reports indicate that responses to cryosupernatant may be seen in patients refractory to FFP, and this approach may be appropriate in these patients before one recommends a splenectomy. The literature on refractory TTP treated with cryosupernatant exchange is reviewed.

Cancer chemotherapy-related thrombotic thrombocytopenic purpura: biological evidence of increased nitric oxide production

The occurrence of thrombotic thrombocytopenic purpura (TTP) in cancer patients receiving chemotherapy has been well established; although this entity is rare, its clinical importance seems to be growing. We describe 3 cases of TTP developing in cancer patients receiving different chemotherapeutic regimens. Using a sensitive high-performance liquid chromatographic method, we evaluated the stable nitric oxide end products, nitrite and nitrate, in the plasma of these patients. Nitric oxide is one of the key components involved in maintaining the normal nonthrombogenicity of the vascular endothelium. In our 3 patients, we found increased nitrate titers that were substantially higher than those observed in patients with de novo TTP. The observed increased release of nitrate could be interpreted as the consequence of massive disruption of endothelial integrity, with consequent passive nitric oxide release in vivo, or an adaptive mechanism of the endothelium to compensate for diffuse microvascular occlusion. The 2 mechanisms may both be involved, but the normal titers of nitric oxide end products in de novo TTP suggest that the former mechanism is more important, at least in cancer chemotherapy-related TTP.

Thrombotic thrombocytopenic purpura: diagnosis, pathogenesis and modern therapy

Thrombotic thrombocytopenic purpura (TTP) is an uncommon multisystem disorder, sometimes associated with predisposing conditions such as pregnancy, cancer, exposure to certain drugs, bone marrow transplantation and HIV-1 infection. An abnormal interaction between the vascular endothelium and platelets which occurs in certain organs leads to thrombosis, endothelial proliferation, minimal inflammation and micro-angiopathic haemolysis. Recent studies suggest that endothelial cell perturbation and apoptosis caused by an as yet unknown plasma factor(s) may lead to the release of abnormal von Willebrand factor which facilitates the deposition of platelet microthrombi. Exchange transfusions of plasma or plasma-cryosupernatant remain the cornerstone of the treatment of TTP along with corticosteroids, platelet inhibitor drugs, vincristine and splenectomy. In most cases remissions can be attained, and cures are now common-although approximately one-half of the patients will relapse. While relapses are usually milder, they still carry a significant mortality and preventive therapies are not always effective.

Thrombocytopenia in pregnancy

Thrombocytopenia is a common finding in normal pregnancy. The introduction of routine automated complete blood counting has clearly documented this. In the past, these patients would go undetected and be spared unnecessary testing, procedures, or medications. This article reviews the common causes of thrombocytopenia and offers criteria on which the diagnosis of clinically significant thrombocytopenia can be made. In addition, we will discuss therapeutic approaches to manage patients with pathologic thrombocytopenia.

Thrombotic thrombocytopenic purpura and relapses: why do case series differ? The Italian Cooperative Group for TTP

We examined the retrospective case series of the Italian Cooperative Group to determine the incidence of relapses in TTP patients. Of 60 patients who have crossed the 10-year threshold from the first episode, only 9 (15%) relapsed during that period, a figure far lower than that reported recently. Such difference is hardly explainable on the basis of our current knowledge of the biological behaviour of TTP. Furthermore, we unsuccessfully analyzed the treatment performed in each of our relapsed patients, in search of some element that could retrospectively predict the subsequent relapse.

Familial relapsing thrombotic micro-angiopathy in two siblings

Two siblings, a 12-year-old girl and a 7-year-old boy, had recurrent episodes of haemolytic-uraemic syndrome/thrombotic thrombocytopenic purpura, manifested mainly by thrombocytopenia and micro-angiopathic haemolytic anaemia. During 11 years of follow up the girl responded only to steroids, whereas many other therapeutic modalities were ineffective. Following treatment with low dose danazol relapses became fewer and of diminished severity and completely subsided after 6 months. The boy started his illness with signs of haemolytic uraemic syndrome and later developed neurological manifestations. During a 6 year follow up he responded only to plasma exchange. Although chronic thrombocytopenia persisted during the past 3 years, the boy's clinical condition improved.

CONCLUSION

A family with two children with recurrent episodes of thrombotic thrombocytopenic purpura is described. In one child danazol could have had a beneficial effect.

Therapy and prevention of thrombotic thrombocytopenic purpura during pregnancy: a clinical study of 16 pregnancies

Thrombotic thrombocytopenic purpura (TTP) is a severe multisystem disorder of unknown pathogenesis, with preference to women. The mortality rate of patients with TTP was 90% until the introduction of plasma therapy that increased the survival rate to 70-80%, with minimal or no sequelae. Of the survivors, 30-60% suffer from relapses, often in association with precipitating factors such as infections, surgery, and pregnancy. Women who are either pregnant or in the postpartum period make up 10-25% of TTP patients, and once the disease occurs during a pregnancy, it tends to recur in subsequent ones. We treated five women who suffered at least one TTP episode during pregnancy. They had a total of 16 pregnancies, eight of which were complicated by TTP. They suffered seven additional TTP episodes that were not associated with pregnancy. We assessed the severity of each TTP episode with a scoring system used in our previous studies. Presented is the course of their disease and their pregnancies, and guidelines for the management and prevention of TTP during pregnancy are provided.