Thrombotic microangiopathy and indications for therapeutic plasma exchange

Investigation of the Effect of Therapeutic Plasma Exchange for TAFRO Syndrome: A Pilot Study

TAFRO syndrome is a rare systemic inflammatory disorder with a fatal course. Nevertheless, a definitive treatment strategy has not yet been established. Anti-inflammatory therapies, including glucocorticoid treatment and immunosuppressants, have not been satisfactory. Therefore, new treatment options are needed for patients with TAFRO syndrome. The effectiveness of therapeutic plasma exchange (TPE) has mainly been reported in several case reports. In this case series study, we investigated the effect of TPE on TAFRO syndrome. We reviewed six consecutive cases with TAFRO syndrome treated at Shinshu University Hospital. All of them underwent TPE. A significant improvement in mean blood pressure, albumin, total bilirubin, and C-reactive protein was observed after TPE. Furthermore, early TPE treatment was suggested to have an impact on the prognosis. More intensive studies are needed to emphasize the overall conclusion obtained that TPE can be an effective/acceptable treatment option for TAFRO syndrome.

Reversible skin microvascular hyporeactivity in patients with immune-mediated thrombocytopenic thrombotic purpura

BACKGROUND

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare disease characterized by arteriolar and capillary microthrombosis precipitating organ failure. However, the contribution of endothelial dysfunction on impaired microvascular blood flow in iTTP patients has been poorly explored. This pilot observational study aimed to explore endothelial-mediated vasoreactivity in iTTP patients at admission and its changes after plasma exchange therapy (PE).

METHODS

We conducted a prospective observational study in patients (> 18-year old) admitted in ICU for iTTP. Using laser Doppler flowmetry and acetylcholine (Ach) iontophoresis in the forearm, we recorded the skin microvascular blood flow and the endothelium-mediated vasoreactivity at admission and after PE. Demographics, biological, clinical courses, and outcomes were also collected. As a control group, we used a previously published cohort of young diabetic patients after correction of ketoacidosis.

RESULTS

Eighteen confirmed iTTP patients and 34 controls were included in the study, mainly female (72%) aged 43 ± 16-year-old. At admission, 55% had neurological abnormalities, 50% cardiac issues and 27.8% an acute kidney injury. Median platelet count was 19 G/mL [10-37]. Baseline microvascular blood flow was decreased in iTTP patients when compared to controls (5.97 ± 4.5 vs. 10.1 ± 6.3 PU, P = 0.03), associated with markedly impaired endothelial-mediated skin microvascular reactivity (AUC: 9627 ± 8122 vs. 16,475 ± 11,738, P = 0.03). Microvascular reactivity improved after the first PE session (AUC: 9627 ± 8122 vs 16,558 ± 10,699, P = 0.007, respectively, baseline and post-PE1) and much more after the second session (26,431 ± 23,181, P = 0.04 post-PE1 vs post-PE2). Hemolysis biomarkers (LDH and bilirubin) negatively correlated with skin microvascular flow and vasoreactivity.

CONCLUSION

We highlighted a marked yet reversible skin endothelium-mediated microvascular hyporeactivity in iTTP patients that could participate in organ injury pathophysiology.

Coronavirus Disease 2019-Associated Thrombotic Microangiopathy: Literature Review

Coronavirus disease 2019 (COVID-19) can lead to clinically significant multisystem disorders that also affect the kidney. According to recent data, renal injury in the form of thrombotic microangiopathy (TMA) in native kidneys ranks third in frequency. Our review of global literature revealed 46 cases of TMA in association with COVID-19. Among identified cases, 18 patients presented as thrombotic thrombocytopenic purpura (TTP) and 28 cases presented as atypical hemolytic uremic syndrome (aHUS). Altogether, seven patients with aHUS had previously proven pathogenic or likely pathogenic genetic complement abnormalities. TMA occurred at the time of viremia or even after viral clearance. Infection with COVID-19 resulted in almost no or only mild respiratory symptoms in the majority of patients, while digestive symptoms occurred in almost one-third of patients. Regarding the clinical presentation of COVID-19-associated TMA, the cases showed no major deviations from the known presentation. Patients with TTP were treated with plasma exchange (88.9%) or fresh frozen plasma (11.1%), corticosteroids (88.9%), rituximab (38.9%), and caplacizumab (11.1%). Furthermore, 53.6% of patients with aHUS underwent plasma exchange with or without steroid as initial therapy, and 57.1% of patients received a C5 complement inhibitor. Mortality in the studied cohort was 16.7% for patients with TTP and 10.7% for patients with aHUS. The exact role of COVID-19 in the setting of COVID-19-associated TMA remains unclear. COVID-19 likely represents a second hit of aHUS or TTP that manifests in genetically predisposed individuals. Early identification of the TMA subtype and appropriate prompt and specific treatment could lead to good outcomes comparable to survival and recovery statistics for TMA of all causes.

Targeting the innate repair receptor axis via erythropoietin or pyroglutamate helix B surface peptide attenuates hemolytic-uremic syndrome in mice

Hemolytic-uremic syndrome (HUS) can occur as a systemic complication of infections with Shiga toxin (Stx)-producing Escherichia coli and is characterized by microangiopathic hemolytic anemia and acute kidney injury. Hitherto, therapy has been limited to organ-supportive strategies. Erythropoietin (EPO) stimulates erythropoiesis and is approved for the treatment of certain forms of anemia, but not for HUS-associated hemolytic anemia. EPO and its non-hematopoietic analog pyroglutamate helix B surface peptide (pHBSP) have been shown to mediate tissue protection via an innate repair receptor (IRR) that is pharmacologically distinct from the erythropoiesis-mediating receptor (EPO-R). Here, we investigated the changes in endogenous EPO levels in patients with HUS and in piglets and mice subjected to preclinical HUS models. We found that endogenous EPO was elevated in plasma of humans, piglets, and mice with HUS, regardless of species and degree of anemia, suggesting that EPO signaling plays a role in HUS pathology. Therefore, we aimed to examine the therapeutic potential of EPO and pHBSP in mice with Stx-induced HUS. Administration of EPO or pHBSP improved 7-day survival and attenuated renal oxidative stress but did not significantly reduce renal dysfunction and injury in the employed model. pHBSP, but not EPO, attenuated renal nitrosative stress and reduced tubular dedifferentiation. In conclusion, targeting the EPO-R/IRR axis reduced mortality and renal oxidative stress in murine HUS without occurrence of thromboembolic complications or other adverse side effects. We therefore suggest that repurposing EPO for the treatment of patients with hemolytic anemia in HUS should be systematically investigated in future clinical trials.

Diagnosis of thrombotic microangiopathy in preeclampsia in the common marmoset (Callithrix jacchus) and treatment by cesarean section

A pregnant common marmoset (Callithrix jacchus) showed tachypnea, hypothermia, and anorexia at close to the expected delivery date. Severe anemia and thrombocytopenia, schistocytes, and high levels of LDH and D-dimer were observed. Three days after the onset of clinical signs, a cesarean section was conducted due to stillbirth. Marmoset immediately recovered after surgery, and the abnormal CBC and blood chemistry parameters before surgery returned to the normal ranges. Diagnosis of pregnancy-associated thrombotic microangiopathy was made because removal of infant and placenta is curative. To the best of our knowledge, this is the first case report of thrombotic microangiopathy in a marmoset with preeclampsia.

Treatment of Shiga-Toxin Hus with Severe Neurologic Features with Eculizumab

Hemolytic Uremic Syndrome (HUS) is a constellation of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Shiga toxin-producing Escherichia coli- (STEC-) mediated HUS is a common cause of acute renal failure in children and can rarely result in severe neurological complications such as encephalopathy, seizures, cerebrovascular accidents, and coma. Current literature supports use of eculizumab, a monoclonal antibody that blocks complement activation, in atypical HUS (aHUS). However, those with neurologic complications from STEC-HUS have complement activation and deposition of aggregates in microvasculature and may be treated with eculizumab. In this case report, we describe a 3-year-old boy with diarrhea-positive STEC-HUS who developed severe neurologic involvement in addition to acute renal failure requiring renal replacement therapy. He was initiated on eculizumab therapy, with clinical improvement and organ recovery. This case highlights systemic complications of STEC-HUS in a pediatric patient. The current literature is limited but has suggested a role for complement mediation in cases with severe complications. We review the importance of early recognition of complications, use of eculizumab, and current data available.

Severe Vitamin B12 Deficiency Mimicking Microangiopathic Hemolytic Anemia

Most individuals with vitamin B12 deficiency present with anemia, fatigue, and neurologic disturbances such as paresthesia and loss of sensory function if chronic. However, in severe states, it may manifest as hemolytic anemia, thrombocytopenia, schistocytosis, elevated lactate dehydrogenase, and low reticulocyte production. This phenomenon is known as pseudo-thrombotic microangiopathy (TMA), and is most commonly due to pernicious anemia. The overlap in clinical presentation with primary TMA creates a challenge in the diagnosis and management of pseudo-TMA. Primary TMA, particularly thrombotic thrombocytopenic purpura, is emergently managed with plasma exchange and may require admission to an intensive care unit due to high risk of mortality. In contrast, pseudo-TMA does not respond to plasma exchange and instead is treated with vitamin B12 supplementation. Patients with this atypical presentation of B12 deficiency may receive unnecessary, costly, and potentially harmful therapy. We present the case of a patient with pseudo-TMA in the setting of pernicious anemia.

Streptococcus Pneumoniae-Associated Hemolytic Uremic Syndrome in the Era of Pneumococcal Vaccine

Streptococcus pneumoniae-associated hemolytic uremic syndrome (Sp-HUS) is a serious complication of invasive pneumococcal disease that is associated with increased mortality in the acute phase and morbidity in the long term. Recently, Sp-HUS definition has undergone revision and cases are categorized as definite, probable, and possible, based on less invasive serological investigations that evaluate Thomsen-Friedenreich crypt antigen (T-antigen) activation. In comparison to the pre-vaccine era, Sp-HUS incidence seems to be decreasing after the introduction of 7-serotype valence and 13-serotype valence pneumococcal vaccines in 2000 and 2010, respectively. However, Sp-HUS cases continue to occur secondary to vaccine failure and emergence of non-vaccine/replacement serotypes. No single hypothesis elucidates the molecular basis for Sp-HUS occurrence, although pneumococcal neuraminidase production and formation of T-antigen antibody complexes on susceptible endothelial and red blood cells continues to remain the most acceptable explanation. Management of Sp-HUS patients remains supportive in nature and better outcomes are being reported secondary to earlier recognition, better diagnostic tools and improved medical care. Recently, the addition of eculizumab therapy in the management of Sp-HUS for control of dysregulated complement activity has demonstrated good outcomes, although randomized clinical trials are awaited. A sustained pneumococcal vaccination program and vigilance for replacement serotypes will be the key for persistent reduction in Sp-HUS cases worldwide.

Kidney transplant in patients with atypical hemolytic uremic syndrome in the anti-C5 era: single-center experience with tailored Eculizumab

RATIONALE AND OBJECTIVE

Patients with atypical hemolytic uremic syndrome (aHUS) have long been considered ineligible for kidney transplantation (KTx) in several centers due to the high risk of disease recurrence, graft loss and life-threatening complications. The availability of Eculizumab (ECU) has now overcome this problem. However, the best approach towards timing, maintenance schedule, the possibility of discontinuation and patient monitoring has not yet been clearly established.

STUDY DESIGN

This is a single center case series presenting our experience with KTx in aHUS.

SETTING AND PARTICIPANTS

This study included 26 patients (16 females) with a diagnosis of aHUS, who spent a median of 5.5 years on kidney replacement therapy before undergoing KTx. We compared the aHUS relapse rate in three groups of patients who underwent KTx: patients who received no prophylaxis, patients who underwent plasma exchange, those who received Eculizumab prophylaxis. Complement factor H-related disease was by far the most frequent etiology (n = 19 patients).

RESULTS

Untreated patients and patients undergoing pre-KTx plasma exchange prophylaxis had a relapse rate of 0.81 (CI 0.30-1.76) and 3.1 (CI 0.64-9.16) events per 10 years cumulative observation, respectively, as opposed to 0 events among patients receiving Eculizumab prophylaxis. The time between Eculizumab doses was tailored based on classic complement pathway activity (target to < 30%). Using this strategy, 12 patients are currently receiving  Eculizumab every 28 days, 5 every 24-25 days, and 3 every 21 days.

CONCLUSION

Our experience supports the prophylactic use of Eculizumab in patients with a previous history of aHUS undergoing KTx, especially when complement dysregulation is well documented by molecular biology.

Therapeutic Plasma Exchange in the Critically Ill Patient: Technology and Indications

Therapeutic plasma exchange (TPE) is frequently the most common Apheresis Medicine technique used for extracorporeal therapy of a wide variety of renal, neurological, hematological, and other clinical indications. Many of these clinical indications require intensive care during critical illness. Conventional TPE uses one of two main technical methods to achieve the goal of removing known disease mediators from the plasma: using centrifugal forces to separate and remove components of blood, or a membrane filtration method that separates plasma from the cellular components of blood. The following review discusses the basic principles of TPE, the technological aspects, and relevant clinical scenarios encountered in the intensive care unit, including relevant guidelines and recommendations from the American Society for Apheresis.

Why thromboembolism occurs in some patients with thrombocytopenia and treatment strategies

Platelets play such an important role in the process of thrombosis that patients with thrombocytopenia generally have an increased risk of bleeding. However, abnormal thrombotic events can sometimes occur in patients with thrombocytopenia, which is unusual and inexplicable. The treatments for thrombocytopenia and thromboembolism are usually contradictory. This review introduces the mechanisms of thromboembolism in patients with different types of thrombocytopenia and outlines treatment recommendations for the prevention and treatment of thrombosis. According to the cause of thrombocytopenia, this article addresses four etiologies, including inherited thrombocytopenia (Myh9-related disease, ANKRD26-associated thrombocytopenia, Glanzmann thrombasthenia, Bernard-Soulier syndrome), thrombotic microangiopathy (thrombotic thrombocytopenic purpura, atypical hemolytic uremic syndrome, hemolytic uremic syndrome, Hemolysis Elevated Liver enzymes and Low Platelets syndrome, disseminated intravascular coagulation), autoimmune-related thrombocytopenia (immune thrombocytopenic purpura, antiphospholipid syndrome, systemic lupus erythematosus), and acquired thrombocytopenia (Infection-induced thrombocytopenia and drug-induced thrombocytopenia, heparin-induced thrombocytopenia). We hope to provide more evidence for clinical applications and future research.

Predictors of In-Hospital Mortality in Thrombotic Thrombocytopenic Purpura in Children in the United States: A Population Analysis

BACKGROUND

Despite proven efficacy and increased availability of therapeutic plasma exchange, thrombotic thrombocytopenic purpura (TTP) is associated with significant morbidity and mortality.

STUDY DESIGN AND METHODS

This study utilized the Kids' Inpatient Database and National Inpatient Sample (2003 to 2016) to study predictors of in-hospital mortality in hospitalized TTP patients. Adjusted odds ratios of death with various putative risk factors were calculated using multiple regression analysis.

RESULTS

Among 1568 hospitalizations with TTP as primary admission diagnosis who underwent therapeutic plasma exchange, 69 deaths were identified (all-cause mortality, 0.04%; median time-to-death, 6 wk). Overall, hospitalizations rates were fairly similar across the study period. The overall incidence of TTP related hospitalizations is 1.51 per 100,000 hospitalizations. A total of 69 deaths were reported with an all-cause in-hospital mortality rate of 0.04% (69/1568). The median time-to-death was 6 weeks. The majority of deaths occurred in age 16 to 20 years (58%), females (56.5%), and African American (42.9%) as shown in Table 2. Mean age for nonsurvivors was 14 years and the mean age of 15 years for survivors (P=0.01). Younger age, male sex, African-American ethnicity, malignancy, sepsis, acute kidney injury, platelet transfusion was significantly associated with mortality in patients with TTP.

CONCLUSIONS

Early and targeted therapy for high risk individuals should be used to guide management of TTP patients for improved survival outcomes.

Expert consensus on the diagnosis and treatment of thrombocytopenia in adult critical care patients in China

Thrombocytopenia is a common complication of critical care patients. The rates of bleeding events and mortality are also significantly increased in critical care patients with thrombocytopenia. Therefore, the Critical Care Medicine Committee of Chinese People's Liberation Army (PLA) worked with Chinese Society of Laboratory Medicine, Chinese Medical Association to develop this consensus to provide guidance for clinical practice. The consensus includes five sections and 27 items: the definition of thrombocytopenia, etiology and pathophysiology, diagnosis and differential diagnosis, treatment and prevention.

HEMOLYTIC UREMIC SYNDROME ASSOCIATED WITH STREPTOCOCCUS PNEUMONIAE IN PEDIATRICS: A CASE SERIES

Objective:

To describe a case series of four (4) patients with hemolytic uremic syndrome due to Streptococcus pneumoniae in a level four complexity institution in the city of Bogotá, D.C., Colombia.

Cases description:

We describe cases of four patients who presented respiratory symptoms and fever. All four patients were in regular conditions on hospital admission, after which they required intensive care and ventilatory support. Upon admission, three cases showed evidence of pleuropulmonary complication. Penicillin-sensitive Streptococcus pneumoniae was isolated in all cases. All patients presented anemia, severe thrombocytopenia, schistocytes on peripheral blood smear, and hyperazotemia. They required blood transfusion and renal replacement therapy during their hospitalization. The patients were diagnosed with hemolytic uremic syndrome due to S. pneumoniae. Three of the four patients had a progressive recovery of the renal function and were discharged after an average of 36 days of hospital stay. The remaining patient had two amputations in the extremities due to thrombotic vascular complications and was discharged after 99 days of hospital stay, requiring hemodialysis every other day.

Comments:

Hemolytic uremic syndrome due to Streptococcus pneumoniae is a rare but severe complication of invasive pneumococcal disease. Complicated pneumonia is the main condition associated with this entity. It is noteworthy the short period in which these cases were presented, considering the low annual incidence of the disease.

Sepsis and septic shock: endothelial molecular pathogenesis associated with vascular microthrombotic disease

In addition to protective “immune response”, sepsis is characterized by destructive “endothelial response” of the host, leading to endotheliopathy and its molecular dysfunction. Complement activation generates membrane attack complex (MAC). MAC causes channel formation to the cell membrane of pathogen, leading to death of microorganisms. In the host, MAC also may induce channel formation to innocent bystander endothelial cells (ECs) and ECs cannot be protected. This provokes endotheliopathy, which activates two independent molecular pathways: inflammatory and microthrombotic. Activated inflammatory pathway promotes the release of inflammatory cytokines and triggers inflammation. Activated microthrombotic pathway mediates platelet activation and exocytosis of unusually large von Willebrand factor multimers (ULVWF) from ECs and initiates microthrombogenesis. Excessively released ULVWF become anchored to ECs as long elongated strings and recruit activated platelets to assemble platelet-ULVWF complexes and form “microthrombi”. These microthrombi strings trigger disseminated intravascular microthrombosis (DIT), which is the underlying pathology of endotheliopathy-associated vascular microthrombotic disease (EA-VMTD). Sepsis-induced endotheliopathy promotes inflammation and DIT. Inflammation produces inflammatory response and DIT orchestrates consumptive thrombocytopenia, microangiopathic hemolytic anemia, and multiorgan dysfunction syndrome (MODS). Systemic inflammatory response syndrome (SIRS) is a combined phenotype of inflammation and endotheliopathy-associated (EA)-VMTD. Successful therapeutic design for sepsis can be achieved by counteracting the pathologic microthrombogenesis.

Eculizumab in STEC-HUS: need for a proper randomized controlled trial

Hemolytic uremic syndrome caused by Shiga toxin-producing E. coli (STEC-HUS) is often associated with a severe morbidity including neurological involvement and a mortality of 1-5%. Although STEC-HUS is often self-limited, improvement of treatment strategies is needed for cases with complications and, among others, plasma exchange/plasmapheresis and use of antibiotics have been advocated. With the availability of the complement blocker eculizumab, now a standard treatment of atypical HUS, several series have addressed its use in STEC-HUS, with variable response; randomized controlled trials are lacking.In this issue of Pediatric Nephrology, Pecheron et al. present a cohort of 33 pediatric patients with severe HUS treated with eculizumab. Neurological involvement was observed in 85% of the patients and 94% required dialysis. Most patients (55%) did not benefit from eculizumab and renal dysfunction as well as neurological sequelae did not resolve. In a subgroup of patients, however, rapid neurological improvement was described. In the post-hoc-defined group of patients with favorable outcome, there was a trend towards more sustained complement inhibition, although this finding was not significant compared to patients with an unfavorable outcome.Because multiple interventions were used and the study did not include any control group, future controlled studies are urgently needed to resolve the debate as to whether eculizumab can be an effective treatment for both prevention and treatment of complications in STEC-HUS.

What is the evidence for the role of therapeutic apheresis in the management of complement-associated thrombotic microangiopathies?

Thrombotic microangiopathies (TMAs) are disorders characterized by endothelial cell activation, microangiopathic hemolytic anemia, thrombocytopenia and organ failure of variable intensity. The pathophysiology of various types of TMAs have become an interesting field of study. Alternative complement system activation plays an important role in several pathophysiological conditions. Complement activation is also described in an increasing number of TMAs. Inherited defects in complement regulatory genes and acquired autoantibodies against complement regulatory proteins have been described. Atypical hemolytic uremic synrome (HUS) is caused by uncontrolled activation of the alternative complement system, now called complement-mediated TMAs. Recently, application of a monoclonal antibody that specifically binds to C5 became available to treat patients with complement-mediated TMAs. Eculizumab is a humanized monoclonal antibody that blocks complement C5 activation. Empiric therapeutic apheresis is also recommended in all forms of complement-mediated TMAs. The justification for therapeutic apheresis use in all forms of complement-mediated TMAs is that it can effectively remove the autoantibodies or mutated circulating complement regulators while replacing absent or defective complement regulators. Currently, therapeutic apheresis and eculizumab are the available treatment options for complement-mediated TMAs. In this paper, we review the evidence for the role of therapeutic apheresis in the management of complement-associated TMAs.

New-onset acute thrombocytopenia in hospitalized patients: pathophysiology and diagnostic approach

Thrombocytopenia is a hematological finding commonly encountered in daily clinical practice from asymptomatic clinic patients to critically ill intensive care unit patients. A broad spectrum of etiologies and variation in clinical presentation often present a diagnostic challenge. Furthermore, concomitant presence of thrombosis and thrombocytopenia, as in cases of thrombotic thrombocytopenia, complicates the management. In hospitalized patients, new-onset thrombocytopenia is an important reason for hematology consultation. Therefore, it is of utmost importance that the etiology is diagnosed accurately. In addition, a basic understanding of the pathophysiology and the differential diagnosis avoids delay in the diagnosis and leads to rapid initiation of treatment. This review will address causes of thrombocytopenia that arises in hospitalized patients with an emphasis on the pathophysiological basis of each disorder.

A rare case of thrombotic microangiopathy triggered by acute pancreatitis

Thrombotic microangiopathy (TMA) occurring after acute pancreatitis is rarely described. Without prompt intervention, TMA can be, and often is, lethal, so prompt recognition is important. Here, we present a case of a 61-year-old woman with a history of alcohol misuse who presented with epigastric pain, nausea and vomiting after binge drinking. Elevated serum lipase and imaging were suggestive of acute-on-chronic pancreatitis. Although the patient's symptoms of acute pancreatitis subsided, her anaemia, thrombocytopenia and acute kidney injury worsened. A peripheral blood smear revealed schistocytes, prompting suspicion for TMA. Therapeutic plasma exchange (TPE) was promptly initiated and she completed 10 TPE sessions that improved her anaemia and serum creatinine and resolved the thrombocytopenia. Since TPE was effective and the ADAMTS13 assay revealed 55% activity in the absence of anti-ADAMTS13 IgG prior to initiation of therapy, a confident diagnosis of TMA caused by acute pancreatitis was made. There was no evidence of relapse 2 years later.

A single-center prospective study on the safety of plasma exchange procedures using a double-viral-inactivated and prion-reduced solvent/detergent fresh-frozen plasma as the replacement fluid in the treatment of thrombotic microangiopathy

BACKGROUND

Patients presenting with acute episodes of thrombotic microangiopathies (TMAs) require urgent access to plasma exchange (PEX). OctaplasLG, a solvent/detergent fresh-frozen plasma product that has undergone viral inactivation and prion reduction step, has been used in our institution since 2013, replacing Octaplas.

STUDY DESIGN AND METHODS

We prospectively reviewed 981 PEX procedures where OctaplasLG was the replacement fluid in 90 patients admitted acutely with a TMA presentation within our institution from January 1, 2013, to December 31, 2015. We recorded citrate toxicities, plasma reactions, viral transfer, complications related to central venous catheter, and venous thrombotic events (VTEs).

RESULTS

Citrate toxicities were 5.4%, plasma reactions were 2%, and all were classified as Grade 1 or 2. VTE had an incidence of 12.2%, although 50% of the episodes occurred in early remission when patients were not receiving PEX. No line insertions complications were recorded. Line-associated infections were 2.2%. Hepatitis B and C serology and human immunodeficiency virus (HIV) were checked on admission. There were four patients who may have had passive transient transfer of hepatitis B antibodies from pooled plasma. No hepatitis C or HIV viral transfer was documented after treatment and no seroconversion was detected after treatment.

CONCLUSION

Our data have demonstrated that the incidence of complications during PEX is low and using OctaplasLG is comparable to the low incidence of reactions. No cases of anaphylaxis, transfusion-related acute lung injury, or fatal plasma reactions were seen. There was no evidence of viral transmission or seroconversion after treatment.

[Hemolytic anemia]

Hemolytic anemia can be caused by various hereditary or acquired diseases. Classification is usually based on corpuscular or extracorpuscular defects. Beside the anemia, laboratory testing indicates increased lactate dehydrogenase, unconjugated bilirubin and reticulocytes as well as reduced or absent plasma haptoglobin. Knowledge of further diagnostic procedures (e.g., Coombs test, schistocytes, hemoglobin electrophoresis or flow cytometric analysis) leads in many cases to an underlying disease with differentiated therapeutic options. Autoimmune hemolytic anemia (AIHA) is often associated with diseases as HIV, connective tissue disease, lymphomas or malignant tumors and the hemolytic process is preexisting in many cases. Thrombotic microvascular diseases (e.g., thrombotic thrombocytopenic purpura or hemolytic-uremic syndrome) are further important causes of hemolytic anemia which need immediate diagnosis and treatment.

Prognostic risk-stratified score for predicting mortality in hospitalized patients with thrombotic thrombocytopenic purpura: nationally representative data from 2007 to 2012

BACKGROUND

Despite proven efficacy and increased availability of therapeutic plasma exchange (TPE), mortality for patients with thrombotic thrombocytopenic purpura (TTP) remains high with a limited understanding of those at highest risk of death.

STUDY DESIGN AND METHODS

This study utilized the Nationwide Inpatient Sample (2007-2012) to derive a prognostic score for mortality in hospitalized TTP patients. Odds ratios of death with various putative risk factors adjusted for age, sex, and race were calculated (adjOR). Weighted mean of adjOR estimates were incorporated in a risk-stratified score.

RESULTS

Among 8203 hospitalizations with TTP as primary admission diagnosis who underwent TPE, 613 deaths were identified (all-cause mortality, 7.5%; median time-to-death, 9 days; interquartile range, 4-14 days). In multivariable logistic regression, arterial thrombosis (adjOR 6.7, 95% confidence interval [CI], 1.1-40.9), intracranial hemorrhage (adjOR, 6.1; 95% CI, 1.6-23.2), age at least 60 years (adjOR, 3.5; 95% CI, 2.1-5.6), renal failure (adjOR, 2.6; 95% CI, 1.5-4.5), ischemic stroke (adjOR, 2.4; 95% CI, 1.2-5.0), platelet (PLT) transfusions (adjOR, 2.2; 95% CI, 1.2-4.1), and myocardial infarction (adjOR, 2.3; 95% CI, 1.2-4.6) were significant independent predictors of mortality in TTP patients who underwent TPE. A prognostic weighted mortality prediction scoring system incorporating arterial thrombosis, intracranial hemorrhage, age, renal failure, ischemic stroke, PLT transfusion, and myocardial infarction showed very good discrimination and was predictive of 78.6% deaths.

CONCLUSIONS

Early and targeted therapy for high-risk individuals should be used to guide management of TTP patients for improved survival outcomes.

Modified Ham test for atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy (TMA) characterized by excessive activation of the alternative pathway of complement (APC). Atypical HUS is frequently a diagnosis of exclusion. Differentiating aHUS from other TMAs, especially thrombotic thrombocytopenic purpura (TTP), is difficult due to overlapping clinical manifestations. We sought to develop a novel assay to distinguish aHUS from other TMAs based on the hypothesis that paroxysmal nocturnal hemoglobinuria cells are more sensitive to APC-activated serum due to deficiency of glycosylphosphatidylinositol- anchored complement regulatory proteins (GPI-AP). Here, we demonstrate that phosphatidylinositol-specific phospholipase C-treated EA.hy926 cells and PIGA-mutant TF-1 cells are more susceptible to serum from aHUS patients than parental EA.hy926 and TF-1 cells. We next studied 31 samples from 25 patients with TMAs, including 9 with aHUS and 12 with TTP. Increased C5b-9 deposition was evident by confocal microscopy and flow cytometry on GPI-AP-deficient cells incubated with aHUS serum compared with heat-inactivated control, TTP, and normal serum. Differences in cell viability were observed in biochemically GPI-AP-deficient cells and were further increased in PIGA-deficient cells. Serum from patients with aHUS resulted in a significant increase of nonviable PIGA-deficient TF-1 cells compared with serum from healthy controls (P < .001) and other TMAs (P < .001). The cell viability assay showed high reproducibility, sensitivity, and specificity in detecting aHUS. In conclusion, we developed a simple, rapid, and serum-based assay that helps to differentiate aHUS from other TMAs.