Thrombotic thrombocytopenic purpura: treatment with plasmapheresis

Initial US tertiary health care system experience using caplacizumab in patients with immune thrombotic thrombocytopenic purpura

Several international registries have reported on the efficacy of caplacizumab for the treatment of immune thrombotic thrombocytopenic purpura (iTTP). Similar real-world data from the United States (US) are limited. In this single center retrospective study, we sought to describe caplacizumab prescribing patterns and review clinical outcomes for US patients with iTTP. Subjects were eligible for inclusion if they were diagnosed with acute iTTP and received care at University of Pittsburgh Medical Center-affiliated hospitals from 2012 to 2022. Subjects were divided into an historical cohort who received standard of care therapy alone, and early and late administration cohorts (EA and LA) who received caplacizumab within and greater than 72 h of admission, respectively, plus standard of care. Clinical data were collected from the electronic record. Thirty-two subjects were included: 16 historical, 12 EA, and 4 LA subjects. Refractoriness occurred more frequently in the LA and historical cohorts as compared to the EA cohort (4 (100%) vs. 6 (38%) vs. 3 (25%), p = 0.02). The LA cohort also experienced longer lengths of hospital stay, required more TPE procedures, and were exposed to the greatest amount of donor plasma (p < 0.05 for all) as compared to the other cohorts. Time to platelet count normalization was longest in the LA cohort (p = 0.013). There were no significant between-group differences in bleeding events. Because we are unable to predict which patients will develop refractoriness, we recommend frontline administration of caplacizumab to all patients with iTTP.

Epidemiology, treatment patterns, clinical outcomes, and disease burden among patients with immune-mediated thrombotic thrombocytopenic purpura in the United States

Background

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a life-threatening thrombotic microangiopathy. Due to its rarity, epidemiology and real-world outcomes data are scarce.

Objectives

The aim was to assess epidemiology, treatment patterns, clinical outcomes, and disease burden in patients with iTTP in the United States.

Methods

This longitudinal, retrospective observational study of the Optum-Humedica database included patients with an iTTP diagnosis (≥1 documented ADAMTS13 activity less than 10% or one or more iTTP episodes) from January 2007 to December 2019.

Results

Of 666 patients with an iTTP diagnosis between October 2015 and December 2019, 302 (45%) had one or more iTTP episodes. The pooled annual incidence of documented iTTP during this period was 3.43/million, and the annual incidence of one or more iTTP episodes was 1.81/million. Patients with one or more iTTP episodes received a median of six therapeutic plasma exchange (TPE) sessions per episode; 86% received corticosteroids, and 59% received rituximab. Exacerbations occurred in 17% (52/302) and relapse in 11% (34/302); 34% (103/302) had one or more thromboembolic events. Mortality rates during the study period were 25% (167/666) among all patients with iTTP diagnosis, and 14% (41/302) among patients with one or more iTTP episodes. In the assessment of disease burden (January 2007 to September 2019), patients in the iTTP cohort (n = 514) presented with a mean of 14 comorbidities, compared with 3 in a matched non-iTTP cohort (n = 2570). In a cluster analysis, duration of iTTP episode and mortality rate were greater in older versus younger patients.

Conclusions

Despite treatment with TPE and immunosuppressants, patients with iTTP have high risk of morbidity and mortality, demonstrating the need for more effective therapies.

Vincristine as an Adjunct to Therapeutic Plasma Exchange for Thrombotic Thrombocytopenic Purpura: A Single-Institution Experience

Background:

Thrombotic thrombocytopenic purpura is a potentially life-threatening condition. Although the introduction of therapeutic plasma exchange has reduced mortality rates from over 90% to 10%-20%, approximately 40% of patients relapse, and outcomes may be fatal in refractory patients. There is clearly a need for additional therapeutic approaches.

Aims:

To describe the outcomes of relapsed/refractory thrombotic thrombocytopenic purpura patients treated with vincristine as an adjunct to therapeutic plasma exchange.

Study Design:

Cross-sectional study.

Methods:

The medical records of all relapsed/refractory patients with thrombotic thrombocytopenic purpura treated with vincristine adjunct to therapeutic plasma exchange between October 2000 and December 2016 were retrospectively reviewed. Diagnosis of thrombotic thrombocytopenic purpura was based on clinical history, physical examination, and laboratory examinations. Patient demographics, laboratory findings, initial date and duration of therapeutic plasma exchange, dosage and time of administration of vincristine, and outcomes were recorded.

Results:

The study included 15 patients [median age: 37 years (range: 26-65); 7 women and 8 men] with either relapsed or refractory thrombotic thrombocytopenic purpura who were treated with vincristine as an adjunct to therapeutic plasma exchange for a total of 22 episodes. Eighty-seven percent of patients achieved remissions in 20 of 22 episodes, with a median duration of remission of 29.5 months (range: 3-105). After a median follow-up of 55 months, 11 patients were alive. Vincristine was well tolerated with no safety concerns.

Conclusion:

Vincristine offers a reasonable option for the treatment of patients with relapsed/refractory thrombotic thrombocytopenic purpura. Further studies evaluating vincristine in the front-line setting and in the relapsed/refractory setting are needed to validate the role of vincristine in thrombotic thrombocytopenic purpura patients.

Long-term outcomes of thrombotic microangiopathy treated with plasma exchange: A systematic review

With the adoption of plasma exchange as standard treatment for thrombotic microangiopathy (TMA), more patients are surviving and long-term outcomes have greater relevance. We conducted a systematic review to synthesize and evaluate the quality of evidence on long-term outcomes of TMA among adults treated with plasma exchange and to identify factors that may be associated with a worse long-term prognosis. We searched databases from 1980 to 2013 for eligible articles published in any language. We included studies that reported outcomes in at least ten adults with a history of TMA treated with plasma exchange and at least 6 months of follow-up. We abstracted data in duplicate and assessed the methodological quality of each study using an assessment tool developed based on recommended validity criteria. We screened 6672 articles, reviewed 213, and included 34 studies totaling 1182 patients (study median [range], 24 [10-118]). The mean (or median) follow-up ranged from 6 months to 13 years. The cumulative incidence of relapse and mortality was highly variable and ranged from 3 to 84 and 0 to 61%, respectively. The incidence of other outcomes across 10 studies also varied (outcomes included hypertension, kidney disease, preeclampsia, stroke, seizure, severe cognitive impairment, and depression); in three other studies, long-term neurocognitive function and health-related quality of life were significantly lower than in the general population. Patients who survive an episode of TMA may be susceptible to long-term vascular complications, but the magnitude of this risk and how to mitigate it remains unclear. Am. J. Hematol. 91:623-630, 2016. © 2016 Wiley Periodicals, Inc.

How I treat refractory thrombotic thrombocytopenic purpura

Acquired thrombotic thrombocytopenic purpura (TTP) is characterized by thrombocytopenia and microangiopathic hemolytic anemia (MAHA) without an obvious cause, and may include fever, mild renal failure, and neurologic deficits. It is characterized by a deficiency of the von Willebrand factor (VWF) cleaving enzyme, ADAMTS13 (a disintegrin and metalloproteinase, with a thrombospondin type 1 motif, member 13), resulting in formation of microthrombi in the high sheer environment of the microvasculature. This causes microvascular occlusion, MAHA, and organ ischemia. Diagnosis is based on the presence of clinical symptoms, laboratory aberrations consistent with MAHA, decreased ADAMTS13 activity, and possibly presence of anti-ADAMTS13 autoantibodies. Upfront treatment of acute TTP includes plasma exchange and corticosteroids. A significant number of patients are refractory to this treatment and will require further interventions. There are limited data and consensus on the management of the refractory TTP patient. Management involves simultaneously ruling out other causes of thrombocytopenia and MAHA, while also considering other treatments. In this article, we describe our management of the patient with refractory TTP, and discuss use of rituximab, increased plasma exchange, splenectomy, and immunosuppressive options, including cyclophosphamide, vincristine, and cyclosporine. We also review recent evidence for the potential roles of bortezomib and N-acetylcysteine, and explore new therapeutic approaches, including recombinant ADAMTS13 and anti-VWF therapy.

Thrombotic thrombocytopenic purpura in 166 pregnancies: 1955-2006

A review of pregnancy-associated thrombotic thrombocytopenic purpura (TTP) in 166 pregnancies was undertaken using 92 English-language publications from 1955 to 2006. Initial and recurrent TTP presents most often in the second trimester (55.5%) after 1-2 days of signs/symptoms; postpartum TTP usually occurs following term delivery. TTP with preeclampsia (n = 28) exhibits 2-4 times higher aspartate aminotransferase (AST) values and lower total lactate dehydrogenase (LDH) to AST ratios (LDH to AST ratio = 13:1), compared with TTP without preeclampsia (LDH to AST ratio = 29:1). Maternal mortality is higher with initial TTP (26% vs 10.7%), especially with concurrent preeclampsia (44.4% vs 21.8%, P < .02). Although maternal mortality with TTP has substantially declined when plasma therapy is utilized, delay of diagnosis and therapy for initial TTP confounded by preeclampsia/hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome remains a significant maternal-perinatal threat. Rapid and readily available laboratory testing to quickly diagnose TTP and HELLP syndrome/preeclampsia is desperately needed to improve care.

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.

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.

Current concepts in the diagnosis and management of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura is a multisystem disease characterized by thrombocytopenia, hemolytic anemia, renal failure, fever, and neurologic abnormalities. Plasma exchange has revolutionized the outcome of this entity from a once fatal disease to a disease that potentially is cured or has prolonged remission. The understanding of the pathophysiology of TTP continues to evolve. Recently, investigators showed that a deficiency in a specific plasma protease responsible for cleaving vWf plays a crucial role in the familial form of TTP. This explains in part why patients usually respond to plasma exchange therapy. The identification of a mutation in a specific gene that belongs to the metalloproteinase family located at chromosome 9q34 could have important therapeutic implications. TTP can be induced by certain drugs, especially immunosuppressants, in the setting of bone marrow and solid organ transplantation. This disease also has been described in association with HIV, pregnancy, cancer, and chemotherapy. TTP remains an ideal example of how knowledge about the etiology of a disease can improve therapeutic interventions.

Plasma from patients with thrombotic thrombocytopenic purpura induces activation of human monocytes and polymorphonuclear neutrophils

Thrombotic thrombocytopenic purpura (TTP) is a rare but severe disorder characterized by microangiopathic haemolytic anaemia, consumptive thrombocytopenia, neurological involvement and formation of platelet thrombi in the small vessels. The aetiopathology of TTP and the mechanism behind the beneficial effect of plasma exchange with plasma infusion have not yet been fully elucidated. We have studied the effect of plasma from four patients with TTP on human blood phagocyte activation, as measured by reactive oxygen species (ROS) production and CD11b expression. TTP plasma obtained in the acute phase of the disease induced ROS production by human monocytes and enhanced CD11b expression on neutrophils. This activation effect remained in the cryosupernatant but not in the cryoprecipitate made from TTP plasma, and disappeared when a complete response was achieved by plasma exchange. These findings suggest that activated blood phagocytes may be involved in the pathophysiology of TTP.

Staphylococcus aureus bacteremia as a cause of early relapse of thrombotic thrombocytopenic purpura

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a multisystem disease characterized by the sudden onset of hemolytic anemia, thrombocytopenia, fever, renal failure, and neurologic dysfunction, occurring in various combinations. The most effective treatment of TTP is plasma exchange and the administration of corticosteroids, which reduces mortality from the 90 percent seen in untreated patients to 10 percent.

CASE REPORTS

Two patients responded favorably to plasma exchange and corticosteroid therapy, but their TTP relapsed during treatment. In both cases, the early relapse of TTP was associated with Staphylococcus aureus bacteremia secondary to central line infection. Treatment of the infection and intensification of the plasma exchange regimen resulted in a sustained remission.

CONCLUSION

Infection should be actively sought and treated in TTP patients who are refractory to treatment or in whom an exacerbation of the disease occurs while they are undergoing plasma exchange.

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.

Current Clinical Practice: Current Management of Thrombotic Thrombocytopenic Purpura

Historically, the mortality rate of thrombotic thrombocytopenic purpura (TTP) approached 100%. However, by the 1980's, new therapy was instituted with a vast improvement in survival to 90%. The exact pathogenesis of TTP remains elusive. Yet, despite incomplete understanding of the pathophysiology, outcome has improved due to increased awareness of the symptomatology leading to earlier diagnosis and better supportive care, in addition to effective therapy with plasma exchange. TTP represents a disease in which prompt diagnosis and treatment can lead to a critical difference in clinical outcome.

Clinical outcome in three patients with postpartum hemolytic uremic syndrome treated with frequent plasma exchange

This study reviewed 3 cases of postpartum hemolytic uremic syndrome (HUS) at our hospital over a 3 year period. The 3 patients had clinical and laboratory abnormalities similar to those of 12 patients with other causes of thrombotic microangiopathy presenting during the same time span. Both groups were treated with 4-7 plasma exchange treatments/week and prednisone, 60 mg/day or its intravenous equivalent, until remission. The postpartum HUS patients had a more complicated, prolonged course; 3 of 3 required dialysis compared to 4 of 12 in the nonpostpartum group (p < 0.05), and they required more plasma exchange treatments (49 +/- 17 vs. 10 +/- 8, p = 0.0001) and a longer duration of therapy (70 +/- 31 vs. 19 +/- 17 days, p < 0.01) before remission. All postpartum HUS patients discontinued dialysis and survived whereas 4/12 nonpostpartum patients died before attaining remission. Compared to other variants of thrombotic microangiopathy, postpartum HUS requires a longer duration of therapy, but with aggressive therapy, renal and overall prognoses may be better.

Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome: a multivariate analysis of factors predicting the response to plasma exchange

The aim of this study was to investigate pretreatment prognostic factors that could be useful in predicting the response to plasma exchange in thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS). Thirty-two patients with TTP/HUS, treated with plasma exchange at our institution from 1980 to 1994, were studied. The main clinical and laboratory data at the beginning of plasma exchanges were analyzed by the Cox stepwise logistic regression, applied to either treatment failure or death. Seventeen (53%) patients attained a complete remission and 22 (69%) survived (five in advanced renal failure and long-term hemodialysis). Longer delay in initiating plasma exchanges, presence of stupor or coma, and higher creatinine levels at the beginning of plasma exchanges were independent predictors of treatment failure. Stupor or coma at the beginning of plasma exchanges was the only predictor of mortality from unremitted TTP/HUS. Hemoglobin levels, platelet count, and LDH activity, traditionally envisaged as markers of disease activity, neither correlated with previous duration of TTP/HUS nor had any prognostic value. Early diagnosis of TTP/HUS and prompt initiation of intensive plasma exchange emerged from this study as the most effective interventions for improving the prognosis of TTP/HUS patients.

Serum lactate dehydrogenase and platelet count predict survival in thrombotic thrombocytopenic purpura

A significant number (some 20%) of patients with thrombotic thrombocytopenic purpura do not respond to standard therapy and die. We reasoned that early identification of those who are likely to fail standard therapy would allow the rational introduction of other treatment modalities. To this end we prospectively evaluated 27 consecutive patients, examining serum LDH levels and platelet counts as markers of disease activity and as predictors of outcome. All patients were treated, according to a written protocol, with high volume plasma exchange (35 ml/kg), prednisone, aspirin, and persantine. Twenty-one of the 27 patients (78%) are alive following therapy. Initial LDH and platelet values did not distinguish between the survivors and nonsurvivors. However, by day 3 of therapy both LDH levels and platelet counts differed significantly between the two groups. Mean day 3 LDH level for survivors was 364 units/L, and for nonsurvivors, 891 units/L (P < 0.005). Mean day 3 platelet count for survivors was 119,000/microL, and for nonsurvivors, 46,000/microL (P < 0.005). Receiver Operator Characteristic curves were constructed and assessed by calculating the area under the curve. This analysis showed that LDH is able to discriminate survivorship one day earlier than platelet count. Both LDH level and platelet count are excellent predictors of survival, under standard therapy, after 3 days of treatment. Early identification of those at greatest risk will facilitate the early institution and evaluation of alternative methods of treatment, such as splenectomy, intravenous Ig, or Vincristine.

Transplant-associated thrombotic microangiopathy: the role of IgG administration as initial therapy

Two transplant patients, one a renal-pancreas and the other a liver allograft recipient, are reported. Both developed clinical and histologic evidence of cyclosporine-associated thrombotic microangiopathy and responded favorably to intravenous IgG therapy. An additional 20 cadaveric renal transplant recipients who developed cyclosporine-associated thrombotic microangiopathy are reviewed. The clinical and laboratory presentation of posttransplant thrombotic microangiopathy varied. Elevated serum creatinine and lactic dehydrogenase (LDH) levels were the most consistent, albeit nonspecific, findings at diagnosis. Fourteen of 22 patients (64%) presented with thrombocytopenia and 19 (86%) had a hemolytic anemia verified on diagnosis. Histologic evidence of thrombotic microangiopathy was present in renal biopsies from each of the renal allograft recipients and a skin biopsy from the liver allograft recipient. Treatment included withdrawal or reduction of the cyclosporine dose, plasmapheresis, or administration of intravenous IgG. There was an overall renal allograft loss of 57%, which included five deaths. Symptomatic cytomegalovirus infection was more common than expected in this patient group (P = 0.038) and may, in combination with cyclosporine therapy, have predisposed these patients to develop clinically significant thrombotic microangiopathy. Transplant-associated microangiopathy appears to be a relatively common disorder associated with a substantial increase in early graft loss (P = 0.005) and mortality (P = 0.001).

The changing course of thrombotic thrombocytopenic purpura and modern therapy

Thrombotic thrombocytopenic purpura (TTP) is a multisystem disorder of unknown etiology. Pathologically, there appears to be an abnormal interaction between the vascular endothelium and platelets, but the primary event remains uncertain. While historically, TTP was a fatal disease, dramatic improvement in its outcome has occurred over the past two decades with the development of effective therapy. Plasma infusion or exchange remains the cornerstone of the treatment of TTP, along with corticosteroids, platelet inhibitor drugs, vincristine and splenectomy. This review summarizes the clinical findings, what is known of the pathogenesis and the available therapeutic modalities for TTP. In most cases, remissions can be attained and cures are now common. However, approximately half the patients will relapse. The clinical course at relapse is usually milder than the disease at presentation and less aggressive therapy may be needed. However, relapsing TTP still carries a significant mortality and preventive therapies are not always effective. Further progress may have to await an understanding of the fundamental etiology of this disease.

Inefficacy of intravenous immunoglobulin in patients with low-risk thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome

OBJECTIVE

To assess the efficacy of intravenous immunoglobulin (IVIG), in comparison with plasma exchange (PE), in the treatment of patients with thrombotic thrombocytopenic purpura/hemolytic-uremic syndrome (TTP/HUS).

DESIGN

Prospective, nonrandomized comparative study.

SETTING

Hematology department in a general hospital.

PATIENTS

17 consecutive adult patients, six of them pregnant, with diagnosis of TTP/HUS. Three had a severity score at diagnosis less than or equal to 4 and were treated with IVIG and 14 had a severity score of greater than or equal to 5 and/or were pregnant and received PE. The response was evaluated after 5 days of therapy.

RESULTS

Complete remission was obtained in 0/3 cases treated with IVIG and 10/14 (71%) with PE (Fisher's exact test P = 0.05). Three patients died for widespread TTP-HUS, and four had persistent disease. In three of the four resistant patients, complete remission was obtained by further PE but not by further IVIG. The overall remission rate was 76% (13/17).

CONCLUSIONS

Our study does not confirm the utility of IVIG in the management of TTP-HUS, as suggested by earlier single case reports.

Vincristine therapy for thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a rare disorder characterized by microangiopathic haemolytic anemia, consumption thrombocytopenia, renal impairment, neurological dysfunction, and fever, but all these features are not present in every patient. Although the prognosis of TTP has improved since it was demonstrated that large volumes of fresh frozen plasma (FFP) lead to a remission in most patients, the disease remains fatal in many instances. Therefore, other therapies are often used in TTP, but there is skepticism about their value, since such treatments are often used in combination, making evaluation difficult. This report describes three patients with TTP and a consistent therapeutic response occurring 5 days after vincristine in each of four instances.

Should intravenous immunoglobulin G be first-line treatment for acute thrombotic thrombocytopenic purpura? Case report and review of the literature

Acute thrombotic thrombocytopenic purpura (TTP) is a rare and serious disease. Treatment with prednisone, anticoagulation, antiplatelet drugs, splenectomy, exchange transfusions, vincristine, and plasmapheresis may be effective in some patients, but the response to these therapies is inconsistent and all carry the potential for serious side effects. We, and others, have recently seen dramatic responses to intravenous (IV) immunoglobulin G (IgG) when other treatments have failed. Although IV IgG is expensive, its costs are low compared with those extended plasmapheresis regimens. Since the response to treatment can usually be evaluated within a few days and the side effects appear less than with other treatments, we believe a strong case can be made for the use of IV IgG as first-line therapy for acute TTP. Continued multicenter studies are necessary to finally solve the problem of competing and confusing treatment attempts and synergism of treatment in acute TTP.

Thrombotic thrombocytopenic purpura with terminal pancytopenia

A 27 year old housewife developed thrombotic thrombocytopenic purpura during the twelfth week of pregnancy. She had partial response to initial plasma infusion and subsequent plasmapheresis. However, her clinical course was complicated by the development of severe pancytopenia the consequence of a hypocellular marrow. She succumbed to septicaemic shock one month after diagnosis. The development of hypocellular marrow in thrombotic thrombocytopenic purpura has not been reported before.

Rapid improvement of thrombotic thrombocytopenic purpura with vincristine and plasmapheresis

Many patients with thrombotic thrombocytopenic purpura (TTP) fail to respond to daily plasmapheresis and the results of alternative treatments have been inconsistent. Vincristine was given weekly with continued plasmapheresis to eight patients who were refractory to plasmapheresis, antiplatelet agents, and/or corticosteroids. A rapid response to the vincristine occurred in all eight patients in 5 days with a marked rise in the platelet count and resolution of symptoms. The results in these patients suggest that early initiation of vincristine therapy in conjunction with plasmapheresis is useful in TTP.

Glomerular fibrin deposition and removal

Glomerular fibrin deposits may occur within vessels or in extracapillary crescents. Studies suggest that intravascular thrombosis is promoted by endothelial cell activation/injury, resulting in the release of endothelial-cell-derived tissue factor procoagulant, fibrinolytic inhibitors, platelet activating factor, and large multimers of von Willebrand factor. Fibrin in crescents may arise from coagulation of plasma in Bowman's space mediated by the release of tissue factor from infiltrating macrophages. Glomerular fibrin may be removed by fibrinolytic or phagocytic mechanisms or persist and lead to glomerular obsolescence. Suppression or elimination of factors that promote glomerular fibrin deposition and enhancement of mechanisms that remove glomerular fibrin may be important in the recovery from several forms of human kidney disease.

Successful pregnancies of two patients with relapsing thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura is a severe multisystemic disorder of unknown origin. The association of relapsing TTP with pregnancy is rare but well documented and high mortality rates of mothers and fetuses have been reported so far. Since the introduction of plasma therapy for treating the acute exacerbations of the disease, overall mortality rates have decreased significantly. It is now evident that the manifestations of the disease may reappear even after long disease-free intervals and as many as a third of the recovering patients may develop a relapse. Presented are two TTP patients with relapsing TTP complicating their pregnancies. Prophylactic treatment with aspirin and dipyridamole during their last three successful pregnancies prevented or minimized the severity of TTP relapses. The course of these pregnancies and the management of such patients is discussed.