The role of rituximab in the management of patients with acquired thrombotic thrombocytopenic purpura

ADAMTS13 Testing During Clinical Remission of Immune Thrombotic Thrombocytopenic Purpura: A Critical Review

Immune thrombotic thrombocytopenic purpura (iTTP), an autoimmune disorder characterised by thrombocytopenia and microangiopathic haemolytic anaemia, is associated with significant morbidity. The diagnosis is made when ADAMTS13 activity is <10% in conjunction with supporting clinical features. Treatment includes plasma exchange with immunosuppressive and anti-von Willebrand factor therapies. While diagnosis and management of acute iTTP are well established, our understanding of optimal monitoring during clinical remission remains incomplete. Clinical relapse of iTTP occurs most commonly within the first year of remission, however, there is little consensus as to the frequency of ADAMTS13 monitoring during clinical remission and when to intervene when there is ongoing deficiency. Through selecting studies that performed ADAMTS13 activity testing during clinical remission of iTTP we critically analyse the current research of ADAMTS13 monitoring during clinical remission and suggest areas for further research with a focus on clinically important outcomes.

A Descriptive 5-Year Analysis of the Demographics and Therapies for Patients With Immune Thrombotic Thrombocytopenic Purpura in the USA: A Multicenter Study of 390 Disease Episodes From 2017 to 2021

Immune thrombotic thrombocytopenic purpura (iTTP) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and microvascular occlusion secondary to acquired ADAMTS13 deficiency. Contemporary data regarding iTTP treatment practices in the US, including the use of caplacizumab, are lacking. We aimed to characterize the demographics and therapies, including medications and apheresis practices, in patients with iTTP in the US. We retrospectively analyzed iTTP cases at 15 sites in the US that provide comprehensive care for patients with iTTP. The time-period assessed was from January 1, 2017 to December 31, 2021. Our primary objective was to analyze data by iTTP episode, inclusive of initial episodes and relapses. A total of 390 iTTP episodes were reported for 280 unique individuals (187 females, 93 males). Thirty-day mortality was 3.7% (14/374), and 6-month mortality was 7.4% (27/367). TPE details were reported for 343 episodes, among which 261 underwent at least one procedure (median 6, IQR 3-11). Among the 261 episodes with at least one therapeutic plasma exchange (TPE) performed, 82.0% (214/261) used only plasma. Caplacizumab was used either alone or in combination with other agents in 43 (11.0%) episodes. Management strategies for iTTP remain varied across centers in the US, with a variety of combinations for TPE replacement fluids and therapeutic agents, as well as limited use of caplacizumab. Further research and standardization of treatment regimens may further reduce mortality in this condition.

Therapeutic Plasma Exchange Management for a Pediatric Patient Presenting With Immune Thrombotic Thrombocytopenic Purpura in a Setting of Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is a disorder characterized by hypogammaglobulinemia resulting in recurrent infections. While autoimmune disorders are common in patients with CVID, no association has been reported between CVID and immune thrombotic thrombocytopenic purpura (iTTP), a disorder most often caused by autoantibodies that compromise the activity of the enzyme ADAMTS13. Reduced ADAMTS13 activity results in the accumulation of large von Willebrand factor multimers that can consume platelets and cause microvascular thrombosis and organ injury, ultimately resulting in mortality in most cases of untreated iTTP. Here, we report a 12-year-old male with CVID who developed iTTP, underwent therapeutic plasma exchange (TPE), and subsequently recovered. We conducted a systematic review for other cases of CVID co-occurring with iTTP and present additional cases of this rare presentation. We highlight the importance of prompt recognition of iTTP in a patient with CVID and timely initiation of TPE.

Real-World Data on Effectiveness and Safety of First-Line Use of Caplacizumab in Italian Centers for the Treatment of Thrombotic Thrombocytopenic Purpura: The Roscapli Study

Background/Objectives: Immune thrombotic thrombocytopenic purpura (iTTP) is a thrombotic microangiopathy caused by the formation of anti-ADAMTS13 antibodies. Caplacizumab is approved for the treatment of acute episodes of iTTP in conjunction with plasma exchange (PEX) and immunosuppression. Real-world data for the use of caplacizumab in Italy have been recently published by a limited number of centers located in the northern and middle regions of the country only. Methods: A total of 38 patients with iTTP were enrolled in the study in six Italian centers spread over the entire territory of the country. The patients' data were registered in eCRF. Results: All patients achieved normalization of platelet count (median 2.0 days, IQR: 2-4), within a time significantly shorter than in the absence of caplacizumab, as previously reported in other studies. As to the secondary aims, patients treated with caplacizumab had a few exacerbations (4/38 (10.5%)) and relapses (2/38, 5.3%). No deaths or refractoriness were observed in these patients. The total length of hospitalization was 12 days (IQR: 9-18) and only one patient required 2 days of stay in the intensive care unit. Interestingly, when caplacizumab was initiated within the first 3 days, the plasma exchange (PEX) duration was 9 days (IQR: 8-10), which was significantly lower than those reported in previous studies conducted in the absence of caplacizumab. No severe adverse event was described in the caplacizumab-treated patients. Conclusions: Caplacizumab reduced exacerbations and refractoriness compared with previously reported standard-of-care regimens. When administered in association with PEX and immunosuppressive therapy, caplacizumab provided rapid normalization of platelet count, which was responsible for lower overall hospitalization time, ICU stay, lower exacerbations and relapses compared to previously reported outcomes of studies carried out without caplacizumab.

How Should Complicated Cases of Thrombotic Thrombocytopenic Purpura With Positive Coombs Test Be Treated?

Thrombocytopenia with concomitant anemia is a serious condition with a high mortality risk. Destruction of platelets, i.e., thrombocytopenia, can be secondary to either auto-antibodies (immune-mediated) or mechanical destruction (non-immune-mediated). The Coombs test is a widespread tool to differentiate between the two categories, resulting in different specific treatment approaches for each diagnosis. A peripheral blood smear can also help make the diagnosis; for instance, in cases of mechanical destruction such as thrombotic thrombocytopenic purpura (TTP), the red blood cell (RBC) shape looks fragmented, forming schistocytes. In rare instances, TTP can present with both schistocytes and a positive Coombs test, challenging the diagnosis of TTP. TTP is a hematological emergency requiring appropriate anticipation and the initiation of treatment prior to the confirmatory ADAMTS-13 test results. Mild forms of TTP can be managed with glucocorticoids and therapeutic plasma exchange. Refractory cases need more aggressive additional treatment with caplacizumab and rituximab. Caplacizumab is an expensive medication that is usually reserved for use after confirmation of a TTP diagnosis. The advantage of caplacizumab lies in its targeted mechanism of action against the A1 domain of the von Willebrand multimers that are normally destructed by the ADAMTS-13 enzyme. Here, we present a young female patient with confirmed TTP, and the initial diagnosis was challenged by the presence of antibodies with the Coombs test. Very little research has studied this rare instance and the appropriate treatment. Our case will save many future lives, as clinicians should be more aggressive in treating refractory TTP with a positive Coombs test.

A safe and effective use of caplacizumab in pregnancy-related acquired thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is not uncommonly seen in pregnancy, either with the first episode or with the exacerbation of known disease. The management of TTP in pregnancy can be challenging if there is refractoriness to the use of therapeutic plasma exchange (TPE) and high-dose corticosteroids. Caplacizumab, a vWF-directed humanized antibody fragment, is approved for the treatment of acquired TTP but there is sparse data on its use in pregnant patients. Antenatal and peripartum haemorrhage is a theoretical concern with the use of the medication in the obstetric population. However, as options for treatment of TTP in the patients who have refractory disease are significantly limited, off-label use of caplacizumab to achieve disease control and prevent maternofetal morbidity and mortality is a reasonable consideration. This article described the successful use of caplacizumab in a pregnant patient with acquired TTP and the associated favourable outcome. The patient suffered an exacerbation following initial TPE and became refractory to both plasma exchange and high-dose corticosteroids. Off-label use of caplacizumab resulted in hematologic recovery and successful delivery of a healthy neonate. This case represents a contribution to the sparse literature on the use of this effective medication in an often-challenging clinical situation.

Clinical Features and Risk Factors of Relapse and Mortality in Thrombotic Thrombocytopenic Purpura Patients: A Seven-Year Experience

Background: Thrombotic thrombocytopenic purpura (TTP) is associated with microangiopathic hemolytic anemia, thrombocytopenia, and microvascular thrombosis. No comprehensive report exists on clinical characteristics and risk factors of relapse and mortality in Iranian TTP patients. In this study, we aimed to report clinical features of Iranian TTP patients, to evaluate disease relapse and mortality rate and their associated risk factors. Materials and Methods: This study was a cohort study of patients diagnosed with microangiopathic hemolytic anemia admitted to the Shariati Hospital, Tehran, a referral center for TTP patients, from 2010 to 2017. Demographic, clinical, and laboratory data were recorded and patients were followed for 3 years regarding disease relapse and mortality. Results:  114 patients (80 females, 34 males) with a mean age of 39.3 ± 14.99 years were included.  Hematologic and neurologic symptoms were the most common manifestations. Abnormal laboratory findings at the presentation included thrombocytopenia, anemia, and elevated LDH. All patients were treated with plasma exchange, and 75.5% of them had a response to treatment, while the 3-year relapse and mortality rate was 23.6 and 26.3%.  Lower platelet count was a predictor of disease relapse. Age, hematological, or neurological initial presentation were associated with TTP mortality. Conclusion: Based on the largest study of TTP patients ever in Iran, the demographic and clinical characteristics of Iranian TTP patients are similar to other existing reports. Knowledge of the risk factors for TTP relapse and mortality could be useful to alert hematologists for prompt therapeutic actions when necessary.

Successful Treatment of Refractory Thrombotic Thrombocytopenic Purpura (TTP) With Caplacizumab: A Case Report

We report a female patient who presented with generalized weakness, episodes of altered mental status and slurred speech, and a history of systemic lupus erythematosus. Initial investigations showed profound thrombocytopenia and schistocytosis on peripheral blood smear. PLASMIC score was promptly calculated, and plasma exchange with steroids was initiated based on the initial high PLASMIC score. Bone marrow examination showed hypocellular marrow without any other obvious abnormalities. The patient's platelet counts initially improved but had a quick decline, on which, rituximab and subsequently caplacizumab were introduced. The patient was discharged after stabilization with plasma exchange (PLEX) therapy as needed on an outpatient basis.

Immune thrombotic thrombocytopenic purpura: Spotlight on long-term outcomes and survivorship

Advances in diagnosis and treatment have dramatically improved survival of acute immune thrombotic thrombocytopenic purpura (iTTP) and iTTP has evolved from an acute fatal condition to a chronic relapsing disorder. In addition to the risk of iTTP relapse, iTTP survivors are at risk of multiple adverse health outcomes including higher than expected rates of all-cause mortality, increased rates of stroke and other cardiovascular disease, and higher rates of morbidities such as obesity, hypertension, and autoimmune disorders. iTTP survivors also report neurocognitive impairment, depression, and reduced quality of life. Women with iTTP are at risk for recurrent iTTP, preeclampsia, and other maternal and fetal complications in subsequent pregnancies. ADAMTS13 activity during clinical remission has emerged as an important targetable risk factor for iTTP relapse and other outcomes including stroke and all-cause mortality. This review summarizes current literature regarding the epidemiology and potential mechanisms for adverse long-term sequelae of iTTP, outlines current best practices in iTTP survivorship care, and highlights a research agenda to improve long-term iTTP outcomes.

How I treat thrombotic microangiopathy in the era of rapid genomics

Thrombotic microangiopathy (TMA) encompasses various genetically-driven diseases. The emergence of ultrafast genomic sequencing has recently opened up new avenues of research for genetic investigations in the setting of intensive care units. TMA is likely to be a suitable focus for fast-track genomic sequencing. By establishing an expeditious molecular diagnosis of patients with the complement-dependent hemolytic uremic syndrome, fast-track genomic sequencing allows for the timely implementation or withdrawal of anti-C5 treatment while averting unnecessary, costly, and potentially harmful therapy in patients testing negative for the syndrome. Furthermore, genomics has the potential to reshape the taxonomic classification of TMA owing to comprehensive genomic analysis. The most significant results from such analysis can be categorized as (1) new descriptions of genetic diseases previously not recognized as associated with TMA and (2) an enrichment of the phenotypic spectrum of diseases traditionally related to TMA. The latter draws on the concept of retrophenotyping, wherein genomic investigation precedes full clinical description. By taking precedence over a phenotypic approach, an unbiased genomic-focused analysis maximizes the chances of discovering new descriptions of a given variant. Presented here are 4 cases of TMA which highlight these issues and substantiate the promise of fast-track genomic sequencing.

Thrombotic Thrombocytopenic Purpura: From 1972 to 2022 and Beyond

This review tells the story of my personal experience with thrombotic thrombocytopenic purpura (TTP). It begins with my first encounter with TTP 50 years ago when 2 sisters presented 2 years apart, both pregnant and both died. At that time, I knew nothing about hereditary TTP (hTTP), the risks of pregnancy, or effective treatments. In 1991, a year after I moved to Oklahoma, therapeutic plasma exchange (TPE) was established as an effective treatment. With the availability of effective treatment, the number of patients presenting with suspected TTP soared. The diagnosis of TTP was imprecise. I worked with the Oklahoma Blood Institute (OBI) to understand the management of TTP. Because the OBI provided all TPE procedures for most of Oklahoma, we saw all consecutive patients within a defined geographic area who were identified at a uniform time early in the course of their TTP, without selection or referral bias. It was an inception cohort; this became the Oklahoma TTP Registry. In 2001, we began a very successful collaboration with the University of Bern, Switzerland, to measure ADAMTS13 activity in all of our patients. From our patients, we learned that acquired, autoimmune TTP (iTTP) is a chronic disease with risks for cognitive impairment and depression. Recognition in 2012 of three sisters with hTTP was reminiscent of the beginning of my story. hTTP has risks for multiple severe morbidities, beginning at birth and especially during pregnancy. Future management of both iTTP and hTTP will be more effective and more convenient.

Refractory Thrombotic Thrombocytopenic Purpura to Therapeutic Plasma Exchange

Thrombotic thrombocytopenic purpura (TTP) is a rare, potentially fatal hematologic disorder characterized by microangiopathic hemolytic anemia, thrombocytopenia, and varying signs of visceral ischemia secondary to microvascular thrombosis. TTP is caused by a severe deficiency of ADAMTS13, a protease enzyme responsible for cleaving von Willebrand-factor (vWF) multimers. First-line therapy with plasmapheresis has increased survival rates immensely; however, there are few reported cases that are refractory to standardized treatment. We describe two cases of refractory TTP successfully managed with the addition of caplacizumab, an anti-von Willebrand factor immunoglobulin fragment that inhibits the interaction of vWF multimers with platelets.

TTP: From empiricism for an enigmatic disease to targeted molecular therapies

The 100th anniversary of the first description of Thrombotic Thrombocytopenic Purpura (TTP) as a disease by Dr. Eli Moschcowitz approaches. For many decades, TTP remained mostly a mysterious fatal condition, where diagnosis was often post-mortem. Initially a pentad of symptoms was identified, a pattern that later revealed to be fallible. Sporadic observations led to empiric interventions that allowed for the first impactful breakthrough in TTP treatment, almost 70 years after its first description: the introduction of plasma exchange and infusions as treatments. The main body of knowledge within the field was gathered in the latest three decades: patient registries were set and proved crucial for advancements; the general mechanisms of disease have been described; the diagnosis was refined; new treatments and biomarkers with improvements on prognosis and management were introduced. Further changes and improvements are expected in the upcoming decades. In this review, we provide a brief historic overview of TTP, as an illustrative example of the success of translational medicine enabling to rapidly shift from a management largely based on empiricism to targeted therapies and personalized medicine, for the benefit of patients. Current management options and present and future perspectives in this still evolving field are summarized.

Evaluation and Management of Thrombotic Thrombocytopenic Purpura in the Emergency Department

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is a dangerous condition that can be misdiagnosed in the emergency department.

OBJECTIVE

The purpose of this narrative review article is to provide a summary of the background, pathophysiology, diagnosis, and management of TTP, with a focus on emergency clinicians.

DISCUSSION

TTP is a disorder with microangiopathic hemolytic anemia, severe thrombocytopenia, and multiorgan ischemic injury. It may be acquired or hereditary, and is caused by a reduced amount or function of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13), which is an enzyme involved in cleaving von Willebrand factor. The classic presentation of TTP includes fever, neurologic abnormalities, thrombocytopenia with purpura, microangiopathic hemolytic anemia, and acute renal injury. However, < 7% of cases have all of these findings present. Testing should include a complete blood count, complete metabolic panel, blood smear, coagulation panel, fibrinogen, D-dimer, lactate dehydrogenase, ADAMTS13 level, troponin, human immunodeficiency virus assessment, urinalysis, pregnancy test as appropriate, and electrocardiogram. Management includes hematology consultation if available, plasma exchange and corticosteroids, and treatment of end-organ complications. All patients require admission for treatment and close monitoring.

CONCLUSION

TTP is a potentially dangerous medical condition requiring rapid diagnosis and management. It is essential for emergency clinicians to know how to diagnose and treat this disorder.

An Update on COVID-19 Vaccine Induced Thrombotic Thrombocytopenia Syndrome and Some Management Recommendations

The thrombotic thrombocytopenia syndrome (TTS), a complication of COVID-19 vaccines, involves thrombosis (often cerebral venous sinus thrombosis) and thrombocytopenia with occasional pulmonary embolism and arterial ischemia. TTS appears to mostly affect females aged between 20 and 50 years old, with no predisposing risk factors conclusively identified so far. Cases are characterized by thrombocytopenia, higher levels of D-dimers than commonly observed in venous thromboembolic events, inexplicably low fibrinogen levels and worsening thrombosis. Hyper fibrinolysis associated with bleeding can also occur. Antibodies that bind platelet factor 4, similar to those associated with heparin-induced thrombocytopenia, have also been identified but in the absence of patient exposure to heparin treatment. A number of countries have now suspended the use of adenovirus-vectored vaccines for younger individuals. The prevailing opinion of most experts is that the risk of developing COVID-19 disease, including thrombosis, far exceeds the extremely low risk of TTS associated with highly efficacious vaccines. Mass vaccination should continue but with caution. Vaccines that are more likely to cause TTS (e.g., Vaxzevria manufactured by AstraZeneca) should be avoided in younger patients for whom an alternative vaccine is available.

On the road to eliminating long-lived plasma cells-"are we there yet?"

Central to protective humoral immunity is the activation of B cells and their terminal differentiation into antibody-secreting plasma cells. Long-lived plasma cells (LLPC) may survive for years to decades. Such long-lived plasma cells are also responsible for producing pathogenic antibodies that cause a variety of challenges such as autoimmunity, allograft rejection, and drug neutralization. Up to now, various therapeutic strategies aimed at durably eliminating pathogenic antibodies have failed, in large part due to their inability to efficiently target LLPCs. Several antibody-based therapies have recently gained regulatory approval or are in clinical phases of development for the treatment of multiple myeloma, a malignancy of plasma cells. We discuss the exciting potential of using these emerging cancer immunotherapies to solve the antibody problem.

Unresponsive Thrombotic Thrombocytopenic Purpura (TTP): Challenges and Solutions

Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathy secondary to a severely decreased A Disintegrin And Metalloprotease with ThromboSpondin type 1 repeats 13 (ADAMTS13) activity, resulting in the formation of widespread von Willebrand factor - and platelet-rich microthrombi. ADAMTS13 deficiency is mainly acquired through anti-ADAMTS13 autoantibodies in adults. With modern standards of care, unresponsive TTP has become rarer with a frequency of refractory/relapsing forms dropping from >40% to <10%. As patients with unresponsive TTP are at increased risk of mortality, prompt recognition and early therapeutic intensification are mandatory. Therapeutic options at the disposal of clinicians caring for patients with refractory TTP consist of increased ADAMTS13 supplementation, increased immunosuppression, and inhibition of von Willebrand factor adhesion to platelets. In this work, we focus on possible therapies for the management of patients with unresponsive TTP, and propose an algorithm for the management of these difficult cases.

Recognizing and managing hereditary and acquired thrombotic thrombocytopenic purpura in infants and children

We describe how infants and children with hereditary and acquired autoimmune thrombotic thrombocytopenic purpura (TTP) initially present and how they can be promptly diagnosed and effectively managed. These are uncommon disorders that are commonly misdiagnosed and can be rapidly fatal. TTP is caused by a severe deficiency of the plasma protease, A disintegrin and Metalloprotease with a ThromboSpondin type 1 motif, member 13 (ADAMTS13). Measurement of ADAMTS13 activity is becoming easily accessible. A common presentation of hereditary TTP is neonatal severe hemolysis and hyperbilirubinemia. However, the median age of diagnosis is not until 5.5 years. Plasma is effective treatment for exacerbations and for prophylaxis. Plasma may be replaced by recombinant ADAMTS13 when it becomes available. Acquired TTP is more frequent in older children, in whom it is more common in girls and is commonly associated with systemic lupus erythematosus. For acquired TTP, plasma exchange and immunosuppression are the current treatment for acute episodes; caplacizumab is now commonly used in adults and may replace plasma exchange.

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.

Silent Thrombotic Thrombocytopenic Purpura: PLASMIC, Lessons Learned, and Current Management Overview

Thrombotic thrombocytopenic purpura (TTP) is a rare, life-threatening autoimmune or hereditary thrombotic microangiopathy (TMA) that may be difficult to recognize given the wide spectrum of presenting symptoms. The clinical diagnosis of TTP is based on thrombocytopenia, microangiopathic hemolytic anemia and is confirmed by a disintegrin-like and metalloproteinase with thrombospondin type one motif, member 13 (ADAMTS13) <10%. However, the latter confirmation is not rapidly available, and treatment is typically initiated based on the degree of clinical suspicion. The PLASMIC score was recently developed to distinguish between TMA patients with and without severe ADAMTS13 deficiency and used as an adjunct in the diagnosis of TTP when the clinical picture is not clear. 

Here we present the case of a completely asymptomatic female with no past medical history diagnosed with TTP after evaluation for thrombocytopenia found on a routine wellness visit. A high PLASMIC score was crucial in the decision to initiate treatment given an unusual asymptomatic presentation. 

Clínica neurológica fluctuante: ¿Llamo al neurólogo o al hematólogo?

Objetivos

Resaltar el papel del laboratorio clínico y la pronta comunicación con el servicio de Hematología en el diagnóstico y la rapidez en la instauración del tratamiento de una patología hematológica tan urgente como la Púrpura Trombótica Trombocitopénica (PTT).

Caso clínico

Varón de edad avanzada derivado a Urgencias hospitalarias por su médico de Atención Primaria por trastorno de emisión del lenguaje, asimetría facial y disminución de fuerza en extremidad superior, por lo que se activa el código ictus. Sin embargo, los hallazgos de laboratorio (anemia y trombocitopenia, creatinina, bilirrubina total y LDH elevadas, test de Coombs directo negativo) y presencia de esquistocitos en el frotis de sangre periférica, acaban derivando en un diagnóstico completamente diferente: microangiopatía trombótica tipo PTT.

Conclusiones

La primera orientación diagnóstica de ictus hemisférico izquierdo fue rechazada ante los signos de anemia hemolítica no autoinmune, trombocitopenia sin causa aparente y presencia de esquistocitos. No debemos olvidar que esta patología puede cursar con afectación multiorgánica y características clínicas muy variables. Aunque su diagnóstico definitivo se basa en la determinación de actividad de ADAMTS-13, debido a la elevada mortalidad es necesario instaurar tratamiento de forma inmediata tras su sospecha.

Fluctuating neurological symptoms: should I call the neurologist or the hematologist?

Objectives

The objective of this study was to highlight the role of the clinical laboratory and the relevance of reporting the case immediately to the unit of hematology for the diagnosis and early administration of treatment in the presence of such an urgent hematologic disease as thrombotic thrombocytopenic purpura (TTP).

Case presentation

An elderly patient was referred to the emergency department of our hospital by his general practitioner for speech difficulty, facial asymmetry and weakness in the upper limb. Stroke code was activated. However, laboratory findings (anemia, thrombocytopenia, elevated creatinine, total bilirubin and LDH, negative direct Coombs test) and presence of schistocytes in the peripheral blood smear test were consistent with a completely different diagnosis: TTP thrombotic microangiopathy.

Conclusions

The first diagnostic approach of left hemispheric stroke was not confirmed in the laboratory, with findings of nonautoimmune hemolytic anemia, thrombocytopenia without apparent cause and presence of schistocytes. We should not forget that the clinical manifestations of this condition are widely variable and may include multiorganic dysfunction. Although confirmation of diagnosis is based on ADAMTS-13, its associated high mortalitiy requires immediate treatment on mere suspicion.

Treating thrombotic thrombocytopenic purpura without plasma exchange during the COVID-19 pandemic. A case report and a brief literature review

We report the case of a patient diagnosed with a clinical relapse of acquired immune-mediated thrombotic thrombocytopenic purpura (TTP) who was successfully treated with low-dose rituximab plus corticosteroids without the use of plasma exchange (PEx), which was unavailable at the time due to the COVID-19 pandemic. Rituximab 100 mg weekly for 4 weeks was administered, combined with 1 mg/kg of prednisone, obtaining a complete hematological response in 6 weeks. This case suggests that PEx may be unnecessary for a subset of patients with relapsed TTP who are clinically stable without significant end-organ damage. A brief literature review regarding TTP patients treated without plasma exchange is also included.

Application of the French TMA Reference Center Score and the mortality in TTP Score in de novo and relapsed episodes of acquired thrombotic thrombocytopenic purpura at a tertiary care facility in Spain

Acquired thrombotic thrombocytopenic purpura (aTTP) is still associated with a 10% to 20% death rate and its clinical course is characterized by recurrent episodes in up to 50% of cases. Over the last decade, mortality predicting models like the French TMA Reference Center Score and the Mortality In TTP Score (MITS) have been developed in an attempt to personalize treatment. The objective of the present study was to compare the results in both scores of de novo and relapsed aTTP episodes. For such purpose, a total of 29 episodes of aTTP (16 de novo and 13 relapses) were analyzed. All patients were homogeneously diagnosed and treated. First episodes had a higher score in both models in comparison with relapsed aTTP, (MITS median, 1 r: 1-4 vs 0 r: 1-2, P = .038 and French TMA Reference Center Score median, 2 r: 1-3 vs 1 r: 0-1, P = .006). The prevalence of neurological symptoms was significantly higher in the first episodes (P = .001) and patients >60 years old were more common in this group (P = .013), which may have been related to the results. Platelet count at presentation was higher in recurrences than in the first disease episode (P = .016) and ADAMTS13 activity <5% was more frequent in the last group (P = .016). There was no significant difference in the rate of refractoriness or exacerbations. In conclusion, first aTTP episodes had a higher probability of short-term mortality compared to relapsed aTTP episodes according to the MITS and French TMA Reference Center Score.

Successful use of caplacizumab in a case of refractory acquired thrombotic thrombocytopenic purpura following subacute thyroiditis

Acquired thrombotic thrombocytopenic purpura (aTTP) is a rare condition mainly characterized by microangiopathic hemolytic anemia, thrombocytopenia, reported in approximately three cases per one million adults per year. Some reports describing co-occurrence of aTTP and other autoimmune disorders, as Graves' thyroiditis, are reported. To the best of our knowledge this is the first report describing co-occurrence of subacute thyroiditis and aTTP. The patient was refractory to conventional therapy with plasma exchange, steroids and rituximab but was successfully treated with the addition of caplacizumab, an anti-VWF bivalent variable-domain-only immunoglobulin fragment that inhibits interaction between VWF multimers and platelets.

Outcomes of Immune Thrombotic Thrombocytopenic Purpura (iTTP) With Upfront Cyclophosphamide vs. Rituximab

Background: Immune thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening disorder managed with plasma exchange (PLEX) and steroids. Addition of rituximab (RTX) to initial disease treatment has been shown to lower future relapse rates. Information as to whether upfront cyclophosphamide (CTX) treatment is helpful in reducing relapse is not known.

Methods: In a retrospective cohort study, we identified all patients at our institution diagnosed with iTTP between 2010 and 2019. We analyzed outcomes of cumulative incidence of relapse (CIR) and duration of remission.

Results: Thirty Nine patients were studied. Group A (n = 10) included patients who received upfront PLEX and steroids alone, and Group B (n = 28) included those who received either upfront RTX (n = 23) or CTX (n = 5) in addition to PLEX and steroids. The 2-year CIR was 50% in Group A and 27.7% in Group B, with a median duration of remission of 43.6 months vs. 108.3 months, respectively (p = 0.04). Group A was associated with a HR=8.7 (95% CI: 1.27, 59.45), p = 0.027 for duration of remission. There was no significant difference between CTX and RTX in both outcomes of CIR and duration of remission. We observed a potential impact on remission duration based on the presenting absolute neutrophil count (HR = 0.74, 95% CI: 0.58, 0.96) and serum creatinine (HR = 1.42, 95% CI: 1.03, 1.94).

Conclusion: There was no significant difference in iTTP relapse outcomes between upfront RTX and CTX. Absolute neutrophil count and serum creatinine may have a role in predicting relapse. Larger, prospective studies are needed to evaluate these findings.

Successful management of three patients with autoimmune thrombotic thrombocytopenic purpura with paradigm-changing therapy: Caplacizumab, steroids, plasma exchange, rituximab, and intravenous immunoglobulins (CASPERI)

Autoimmune thrombotic thrombocytopenic purpura (aTTP) is a severe disease caused by the production of autoantibodies against von Willebrand factor (vWF)-cleaving ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin-1 motifs; 13th member of the family). In 2018, caplacizumab was approved for the treatment of patients with acute aTTP in conjunction with plasma exchange (PE) and immunosuppressive therapy. Immunosuppressive standard of care includes mainly steroids whereas rituximab is usually reserved for refractory cases. We report three patients with a first acute episode of aTTP who were successfully treated with a paradigm-changing scheme including standard of care (caplacizumab, steroids and PE) plus upfront therapy with rituximab and intravenous immunoglobulins (CASPERI). Rituximab was added 1-4 days after diagnosis, when ADAMTS13 autoantibodies were detected and intravenous immunoglobulins were administered after performing PE using albumin as replacement solution. Successful outcome was observed in all three patients: platelet recovery (>150 × 10⁹/L) was observed after 3, 4, and 5 days from diagnosis; ADAMTS13 activity >5% and ADAMTS13 autoantibodies were negative after 14, 15, and 21 days from diagnosis. In conclusion, caplacizumab, steroids, PE (using fresh frozen plasma or albumin as replacement solution and adding intravenous immunoglobulins) plus upfront rituximab therapy was a safe and efficient combination to induce remission in case of acute aTTP.

Humanized anti CD-20 as an alternative in chronic management of relapsing thrombotic thrombocytopenic microangiopathy resistant to rituximab due to anti chimeric antibody

Acquired Immune thrombotic thrombocytopenic purpura (iTTP) is considered among clinical situations that needs not only urgent treatment in acute setting but also long term management to prevent relapses. Important progresses have been made in management of these patients that are definitely associated with reduced mortality and relapse rate. However, there are still noticeable percentage of patients that may relapse despite application of modern treatment strategies including preemptive rituximab infusions. Hereby, we share our experience concerning a frequently relapsing iTTP due to development of anti-rituximab antibody. In our case administration of obinutuzumab, a humanized type II anti CD-20 antibody was associated with complete peripheral blood B cell depletion and increasing plasma ADAMTS-13 activity.

A critical evaluation of caplacizumab for the treatment of acquired thrombotic thrombocytopenic purpura

Introduction: Acquired thrombotic thrombocytopenic purpura (aTTP) is a thrombotic microangiopathy caused by inhibitory autoantibodies against ADAMTS13 protein. Until recently, the combination of plasma exchange (PEX) and immunosuppression has been the standard front-line treatment in this disorder. However, aTTP-related mortality, refractoriness, and relapse are still a matter of concern. Areas covered: The better understanding of the pathophysiological mechanisms of aTTP has allowed substantial improvements in the diagnosis and treatment of this disease. Recently, the novel anti-VWF nanobody caplacizumab has been approved for acute episodes of aTTP. Caplacizumab is capable to block the adhesion of platelets to VWF, therefore inhibiting microthrombi formation in the ADAMTS13-deficient circulation. In this review, the characteristics of caplacizumab together with the available data of its efficacy and safety in the clinical setting will be analyzed. Besides, the current scenario of aTTP treatment will be provided, including the role of other innovative drugs. Expert opinion: With no doubt, caplacizumab is going to change the way we treat aTTP. In combination with standard treatment, caplacizumab can help to significantly reduce aTTP-related mortality and morbidity and could spare potential long-term consequences by minimizing the risk of exacerbation.

Assessment and Monitoring of Patients with Immune-Mediated Thrombotic Thrombocytopenic Purpura (iTTP): Strategies to Improve Outcomes

Background

Acquired or immune-mediated TTP (iTTP) is a life-threatening thrombotic microangiopathy, characterized by the presence of microangiopathic hemolytic anemia and severe thrombocytopenia, and a variable degree of ischemic organ damage, related to a severe deficiency of ADAMTS13, which is a serine metalloprotease necessary for cleavage of large vWF multimers. There has been a dramatic decrease in mortality rates with the recognition of the pathophysiology of iTTP over the years. Although therapeutic plasma exchange (TPE) together with corticosteroids are the backbone of the upfront treatment of patients with iTTP with successful outcomes, patients may remain refractory and/or relapse following an initial response to this treatment.

Methods

We performed a review regarding the pathogenesis, diagnosis, treatment strategies, monitoring, and prognosis of iTTP.

Results

There are several new treatment strategies, which can be used among these patients, helping in improving outcomes of iTTP. Rituximab has been shown to be a safe and effective adjunct to TPE, especially in patients with refractory and/or relapse as well as it is increasingly used preemptively to prevent exacerbation or recurrence. Recently, caplacizumab, a nanobody targeting vWF, was approved as an addition to the current regimen of TPE and immunomodulation for patients of iTTP.

Conclusion

Specific predictors of relapse in patients in remission can be relevant for an optimal patient management. Different models including ADAMTS13 biomarkers can provide a new screening strategy to identify patients who may predict outcomes and the risk of relapse, benefit from preemptive therapy prior to relapse.

Thrombotic thrombocytopenic purpura and defective apoptosis due to CASP8/10 mutations: the role of mycophenolate mofetil

Immunological dysregulation may underlie unusual autoimmune diseases, which also deserve to be investigated from a genetic point of view.

Rituximab prolongs the time to relapse in patients with immune thrombotic thrombocytopenic purpura: analysis of off-label use in Japan

Immune thrombotic thrombocytopenic purpura (iTTP) is caused by ADAMTS13 deficiency due to anti-ADAMTS13 autoantibodies. Rituximab, an anti-CD20 monoclonal antibody, is often used to suppress these autoantibodies. This retrospective study, conducted in an iTTP cohort in Japan, evaluated the long-term efficacy of rituximab as off-label treatment for refractory or relapsed cases. A total of 252 iTTP patients with severe ADAMTS13 deficiency (< 10%) and its inhibitor were enrolled, and 169 episodes in 156 patients were analyzed. Sixty-five episodes with relapse or resistance to conventional treatment were treated with rituximab, while 104 episodes received conventional treatment only. The rituximab group had a significantly higher inhibitor titer than the rituximab-untreated group. During the median follow-up period of 3.9 years, there were 8 relapses in the rituximab group and 17 relapses in the rituximab-untreated group. The median time to relapse in the rituximab group (2.9 years) was significantly longer than that in the rituximab-untreated group (1.2 years). Relapse-free survival at 2 years was significantly higher in the rituximab group than in the rituximab-untreated group. The incidence of relapse at 5 years did not differ between the 2 groups. Rituximab reduced the risk of relapse in refractory or relapsed iTTP patients for 2 years.

Atypical Presentation of Thrombotic Thrombocytopenic Purpura without Hematological Features

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disease, usually diagnosed with high index of suspicion. The pathophysiology of TTP is due to severe deficiency of von Willebrand factor cleaving protease, known as ADAMTS 13. Early diagnosis is crucial as without treatment TTP is associated with high mortality rate. Plasma exchange is currently the mainstay of treatment. Nonetheless, the classical pentad of microangiopathic hemolytic anemia (MAHA), thrombocytopenia, neurological dysfunction, kidney dysfunction and fever are seen only in 40 percent of the patients. MAHA and thrombocytopenia are the common presenting features. Presentation with thrombotic complication without hematological features (MAHA and thrombocytopenia) is rare and makes the diagnosis difficult. Herein, we report an unusual presentation of a 53-year-old male, who was initially presented in 2014 with classical features of TTP, however had an atypical presentation of TTP in 2016 with only neurological features without hematological features.

Role of caplacizumab in the treatment of acquired thrombotic thrombocytopenic purpura

Acquired thrombotic thrombocytopenic purpura is a rare blood disorder with a high early mortality rate, if untreated. Standard of care plasma exchange and glucocorticoids have dramatically improved survival. However, additional advancements are necessary to further decrease mortality. Caplacizumab-yhdp (Cablivi®) is the first Food and Drug Administration-approved treatment indicated for adult patients with acquired thrombotic thrombocytopenic purpura, in combination with plasma exchange and immunosuppressive therapy. However, there are considerable risks associated with the use of caplacizumab and they must be weighed against the benefits of the medication.

Thrombotic microangiopathy following heart transplant in pediatric Danon disease

This case describes an uncommon acute complication of diffuse thrombotic angiopathy and associated aHUS/TTP in an 11-year-old girl with Danon disease who underwent orthotopic heart transplant. Shortly after transplant, despite an uncomplicated operative course, the patient developed severe kidney injury and progressive altered mental status, culminating in cerebral edema, brain herniation, and death. She had received a single dose of tacrolimus (FK506) and a single dose of antithymocyte globulin. Sources of progressive somnolence, including oversedation from impaired renal clearance of opiates, and severe myopathy as has been previously described in Danon disease, were ruled out, and the patient continued to decline. Initial brain CT scan early after transplant showed no signs of cerebral edema, but repeat CT indicated severe cerebral edema. Based on autopsy, diffuse thrombotic angiopathy, with signs of hemolytic anemia with schistocytes, was likely responsible for her deterioration in the broader condition of aHUS/TTP.

Predictors of relapse and efficacy of rituximab in immune thrombotic thrombocytopenic purpura

Patients with immune-mediated thrombotic thrombocytopenic purpura (iTTP) often experience life-threatening relapses of the disease, and rituximab (RTX) can be used to mitigate relapse risk. However, the predictors of relapse in iTTP and the magnitude and duration of effect of RTX remain key unanswered questions. Using a multi-institutional cohort of consecutive adult patients with iTTP, we used survival analysis to compare relapse rates between patients who received RTX during the index presentation with acute iTTP and those who did not. Of 124 patients, 60 (48%) received RTX and 34 (27%) experienced relapse. Median time to relapse was 3.71 (interquartile range, 1.75-4.9) and 1.33 (interquartile range, 0.43-2.35) years for RTX-treated and untreated patients, respectively. RTX conferred protection from relapse at 1 year of follow-up (P = .01) but not at 5 years of follow-up. Extended Cox regression was then used to identify predictors of relapse and to estimate the protective effect of RTX. The following parameters were independently associated with increased risk for subsequent relapse: presenting in iTTP relapse (hazard ratio [HR], 2.97; 95% confidence interval [CI], 1.4-6.4), age younger than 25 years (HR, 2.94; 95% CI, 1.2-7.2), and non-O blood group (HR, 2.15; 95% CI, 1.06-4.39). RTX initially provided protection from relapse (HR, 0.16; 95% CI, 0.04-0.70), but this effect gradually diminished, returning to the baseline risk for untreated patients at approximately 2.6 years. Patients who are young, have non-O blood group, or present with relapsed iTTP are at increased risk for subsequent relapse. RTX appears to confer short-term protection from relapse.

Clinical presentation and management of acquired thrombotic thrombocytopenic purpura: A case series of 55 patients

The aim of this study was to explore the clinical characteristics and treatment of acquired thrombotic thrombocytopenic purpura (TTP). The clinical manifestations, laboratory findings, differential diagnoses, therapeutic methods, and prognosis of 55 patients with acquired TTP were retrospectively analyzed. Among the 55 TTP patients, 17 were males and 38 were females, with a mean age of 40 ± 15 years. Twenty-one patients had the Triad syndrome, which included neurological syndromes, microangiopathic hemolytic anemia, and thrombocytopenia. Twenty-three patients had the Quinary syndrome, which included fever, microangiopathic hemolytic anemia, thrombocytopenia, renal insufficiency, and neurological symptoms. Twenty-eight patients received the measurement for a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity and 23 patients had <10% of the normal range. ADAMTS13 inhibitor was tested in 20 patients and was positive in 18 patients. Both ADAMTS13 activity and ADAMTS13 inhibitor were examined in 20 patients and 90% of the patients showed double positive results. The treatment methods included plasma exchange, glucocorticoids, rituximab, immunosuppressants, and intravenous immunoglobulin. Thirty-three patients survived, and 22 patients died. Plasma exchange improved the remission rate from 16.7% to 65.3% (P = .022). The combined immunosuppressive therapy based on plasma exchange and glucocorticoids raised the remission rate from 43.8% to 75.8%. Most of acquired TTP patients had the Triad syndrome or the Quinary syndrome. A high proportion of TTP patients had ADAMTS13 activity reduction and ADAMTS13 inhibitor positivity. Plasma exchange and immunosuppressive therapy may improve the prognosis of this disease.

Thrombotic Thrombocytopenic Purpura, Heparin-Induced Thrombocytopenia, and Disseminated Intravascular Coagulation

Hemostatic abnormalities are common among critically ill patients and are associated with a high risk of bleeding. The abnormalities range from isolated thrombocytopenia or prolongation of global coagulation assays to complex disease states, such as thrombotic microangiopathic syndromes, and can be associated with a wide range of conditions, including trauma, surgery, acute disease processes, cardiopulmonary bypass, and exposure to drugs and blood products. Prompt identification of underlying causes is important because treatment strategies vary. Moreover, prompt initiation of both supportive and specific treatments is vital to decrease the morbidity and mortality in the intensive care unit.

Management of Select Thrombocytopenias

Evaluating, diagnosing, and managing patients with consumptive thrombocytopenia is challenging because of the overlapping nature of many of the diseases that reduce platelet counts. Immune thrombocytopenia (and its variations), drug-induced immune thrombocytopenia, and heparin-induced thrombocytopenia result from autoimmune antibody-mediated destruction of platelets. Thrombotic thrombocytopenia (both congenital and acquired) and the hemolytic uremic syndromes (both typical and atypical) are thrombotic microangiopathies associated with platelet aggregation and consumption along with anemia and renal dysfunction. Rapid history taking, physical assessment, and laboratory evaluation are crucial to accurately managing patients with these disorders. Platelet-associated coagulopathies are infrequently encountered by most providers, and limited exposure to these types of patients, combined with the wide variety of treatment options for reversing bleeding or thrombotic sequelae, makes management difficult. This article reviews the pathophysiology, patient presentation, diagnostic testing, and specific management strategies and challenges of these thrombocytopenias.

Caplacizumab as an emerging treatment option for acquired thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) is a rare disease with a mortality rate of over 90% if left untreated. Therapeutic plasma exchange (PEX) is the mainstay of treatment of acquired TTP (aTTP), and with the introduction of PEX, the mortality rate declined dramatically below 20%. Although PEX together with corticosteroids are the backbone of the upfront management of patients with aTTP with successful outcomes, patients may remain refractory and/or relapse following an initial response to this treatment. There are some therapeutic options, which can be used among these patients, helping in improving outcomes of aTTP. Caplacizumab (formerly ALX-0081 or ALX-0681) is a humanized single-variable domain immunoglobulin that recognizes the human von Willebrand factor (vWF) A1 domain and inhibits the vWF-platelet glycoprotein 1b-alpha (GP1b-α) interaction. The drug was first developed for the prevention of thrombosis in high-risk patients with acute coronary syndrome undergoing percutaneous coronary intervention; however, drug development for this indication has been discontinued. Recently, caplacizumab received its first approval following Phase II TITAN and Phase III HERCULES trials in the European Union (EU) for the treatment of acute episode of aTTP in adult patients, in addition to PEX and immunosuppression. This review focuses on the use of caplacizumab as an emerging treatment option in patients with aTTP.

The remarkable diversity of thrombotic thrombocytopenic purpura: a perspective

Understanding the autoimmune etiology of acquired thrombotic thrombocytopenic purpura (TTP) has provided precision for the diagnosis and a rationale for immunosuppressive treatment. These advances have also allowed recognition of the remarkable clinical diversities of patients' initial presentations and their long-term outcomes. These diversities are illustrated by the stories of patients from the Oklahoma TTP Registry. The initial presentation of TTP may be the discovery of unexpected severe thrombocytopenia in a patient with minimal or no symptoms. The patient may remain asymptomatic throughout treatment or may die suddenly before treatment can be started. ADAMTS13 activity may be reported as normal in a patient with characteristic clinical features of TTP, or the unexpected report of ADAMTS13 deficiency in a patient with another established disorder may lead to the discovery of TTP. ADAMTS13 activity during clinical remission is unpredictable. ADAMTS13 activity may recover and remain normal, it may remain severely deficient for many years, or it may become normal only many years after recovery. Our treatment of initial episodes and management of patients after recovery and during remission continue to change. The addition of rituximab to the treatment of acute episodes and preemptive rituximab for patients with severe ADAMTS13 deficiency during remission are reported to prevent relapse. Because TTP is uncommon, there are few data to guide these changes. Therefore our patients' stories are profoundly influential. Their stories are the foundation of our experience, and our experience is the guide for our decisions.