350 research outputs found
Severe transplantâ associated thrombotic microangiopathy in patients with hemoglobinopathies
Incidence and severity of transplantâ associated thrombotic microangiopathy (TAâ TMA) in patients with hemoglobinopathies receiving hematopoietic cell transplant is unknown. We report the outcomes for two patients with TAâ TMA who received eculizumab. A 2.5â yearâ old male with sickle cell disease developed TAâ TMAâ associated pericardial tamponade, severe hypertension, and acute kidney injury 2 months after transplant. A 7â yearâ old female with βâ thalassemia major developed TAâ TMAâ related acute kidney injury, severe hypertension, and seizures at 6 months after transplant. Both patients progressed to chronic kidney disease (CKD). In patients with hemoglobinopathies, preexisting endothelial dysfunction may place them at a greater risk for TAâ TMA and subsequent CKD.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137747/1/pbc26503.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137747/2/pbc26503_am.pd
The Role of Complement in HSCT-TMA : Basic Science to Clinical Practice
Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a common complication occurring post-HSCT and is associated with substantial morbidity and mortality if not promptly identified and treated. Emerging evidence suggests a central role for the complement system in the pathogenesis of HSCT-TMA. The complement system has also been shown to interact with other pathways and processes including coagulation and inflammation, all of which are activated following HSCT. Three endothelial cell-damaging "hits" are required for HSCT-TMA genesis: a genetic predisposition or existing damage, an endothelial cell-damaging conditioning regimen, and additional damaging insults. Numerous risk factors for the development of HSCT-TMA have been identified (including primary diagnosis, graft type, and conditioning regimen) and validated lists of relatively simple diagnostic signs and symptoms exist, many utilizing routine clinical and laboratory assessments. Despite the relative ease with which HSCT-TMA can be screened for, it is often overlooked or masked by other common post-transplant conditions. Recent evidence that patients with HSCT-TMA may also concurrently present with these differential diagnoses only serve to further confound its identification and treatment. HSCT-TMA may be treated, or even prevented, by removing or ameliorating triggering "hits", and recent studies have also shown substantial utility of complement-targeted therapies in this patient population. Further investigation into optimal management and treatment strategies is needed. Greater awareness of TMA post-HSCT is urgently needed to improve patient outcomes; the objective of this article is to clarify current understanding, explain underlying complement biology and provide simple tools to aid the early recognition, management, and monitoring of HSCT-TMA.Peer reviewe
Role of the lectin pathway of complement in hematopoietic stem cell transplantation-associated endothelial injury and thrombotic microangiopathy.
Hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA) is a life-threatening syndrome that occurs in adult and pediatric patients after hematopoietic stem cell transplantation. Nonspecific symptoms, heterogeneity within study populations, and variability among current diagnostic criteria contribute to misdiagnosis and underdiagnosis of this syndrome. Hematopoietic stem cell transplantation and associated risk factors precipitate endothelial injury, leading to HSCT-TMA and other endothelial injury syndromes such as hepatic veno-occlusive disease/sinusoidal obstruction syndrome, idiopathic pneumonia syndrome, diffuse alveolar hemorrhage, capillary leak syndrome, and graft-versus-host disease. Endothelial injury can trigger activation of the complement system, promoting inflammation and the development of endothelial injury syndromes, ultimately leading to organ damage and failure. In particular, the lectin pathway of complement is activated by damage-associated molecular patterns (DAMPs) on the surface of injured endothelial cells. Pattern-recognition molecules such as mannose-binding lectin (MBL), collectins, and ficolins-collectively termed lectins-bind to DAMPs on injured host cells, forming activation complexes with MBL-associated serine proteases 1, 2, and 3 (MASP-1, MASP-2, and MASP-3). Activation of the lectin pathway may also trigger the coagulation cascade via MASP-2 cleavage of prothrombin to thrombin. Together, activation of complement and the coagulation cascade lead to a procoagulant state that may result in development of HSCT-TMA. Several complement inhibitors targeting various complement pathways are in clinical trials for the treatment of HSCT-TMA. In this article, we review the role of the complement system in HSCT-TMA pathogenesis, with a focus on the lectin pathway
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Outcomes following autologous hematopoietic stem cell transplant for patients with relapsed Wilms' tumor: a CIBMTR retrospective analysis.
Despite the marked improvement in the overall survival (OS) for patients diagnosed with Wilms' tumor (WT), the outcomes for those who experience relapse have remained disappointing. We describe the outcomes of 253 patients with relapsed WT who received high-dose chemotherapy (HDT) followed by autologous hematopoietic stem cell transplant (HCT) between 1990 and 2013, and were reported to the Center for International Blood and Marrow Transplantation Research. The 5-year estimates for event-free survival (EFS) and OS were 36% (95% confidence interval (CI); 29-43%) and 45% (95 CI; 38-51%), respectively. Relapse of primary disease was the cause of death in 81% of the population. EFS, OS, relapse and transplant-related mortality showed no significant differences when broken down by disease status at transplant, time from diagnosis to transplant, year of transplant or conditioning regimen. Our data suggest that HDT followed by autologous HCT for relapsed WT is well tolerated and outcomes are similar to those reported in the literature. As attempts to conduct a randomized trial comparing maintenance chemotherapy with consolidation versus HDT followed by stem cell transplant have failed, one should balance the potential benefits with the yet unknown long-term risks. As disease recurrence continues to be the most common cause of death, future research should focus on the development of consolidation therapies for those patients achieving complete response to therapy
High Dose Methylprednisolone for Veno-Occlusive Disease of the Liver in Pediatric Bone Marrow Transplant Recipients
Outcomes following autologous hematopoietic stem cell transplant for patients with relapsed Wilms’ tumor: a CIBMTR retrospective analysis
Despite the dramatic improvement in the overall survival for patients diagnosed with Wilms’ tumor (WT), the outcomes for those that experience relapse have remained disappointing. We describe the outcomes of 253 patients with relapsed WT who received high-dose chemotherapy (HDT) followed by autologous hematopoietic stem cell transplant (HCT) between 1990 and 2013, and reported to the Center for International Blood and Marrow Transplantation Research (CIBMTR). The 5-year estimates for event free survival (EFS) and overall survival (OS) were 36% (95% CI; 29 – 43%) and 45% (95% CI; 38 – 51%) respectively. Relapse of primary disease was the cause of death in 81% of the population. EFS, OS, relapse and transplant-related mortality (TRM) showed no significant differences when broken down by disease status at transplant, time from diagnosis to transplant, year of transplant or conditioning regimen. Our data suggest that HDT followed by autologous HCT for relapsed WT is well tolerated and outcomes are similar to those reported in the literature. Since attempts to conduct a randomized trial comparing maintenance chemotherapy with consolidation versus high-dose chemotherapy followed by stem cell transplant have failed, one should balance the potential benefits with the yet unknown long-term risks. Since disease recurrence continues to be the most common cause of death, future research should focus on the development of consolidation therapies for those patients achieving complete response to therapy
The Noninvasive Urinary Polyomavirus Haufen Test Predicts BK Virus Nephropathy in Children After Hematopoietic Cell Transplantation: A Pilot Study
After hematopoietic cell transplantation (HCT), polyoma-BK virus is associated with hemorrhagic cystitis and also with polyomavirus nephropathy (PVN). However, the true burden of post-HCT PVN is unknown because kidney biopsies are avoided due to their bleeding risk. The novel, non-invasive urinary PV-Haufen test detects PVN in kidney transplant recipients with >95% positive/negative predictive values. We hypothesized that the detection of PV-Haufen in voided urine samples–a positive PV-Haufen test–was also clinically significant after HCT
Alternate-Day Micafungin Antifungal Prophylaxis in Pediatric Patients Undergoing Hematopoietic Stem Cell Transplantation: A Pharmacokinetic Study
Disseminated fungal infection is a major cause of morbidity and mortality in children undergoing hematopoietic stem cell transplantation (HSCT). Prophylaxis with amphotericin B can be limited by renal toxicity. Oral triazoles can be limited by poor absorption, large interindividual pharmacokinetic (PK) variability, and hepatic toxicity, leading to interruptions in therapy and breakthrough infections. Intravenous (i.v.) micafungin has potential advantages, because of its better safety profile, specifically in terms of hepatic and renal toxicity, and lack of drug-drug interactions with common medications used in the HSCT setting. We hypothesized that higher dose micafungin (3 mg/kg) every other day will provide drug exposure similar to standard dosing (1 mg/kg) given daily, and improve patient compliance in very young children in whom oral medications can be challenging, at reduced administration costs. Both animal and adult patient data support the use of this approach. Fifteen children (M/F = 11/4, aged ≤10 years; mean: 3.9 years, range: 0.6-10 years) with various hematologic, metabolic, and immune deficiency disorders undergoing HSCT received a single dose of micafungin (3 mg/kg) i.v. over 1 hour. Dose selection was based on published PK data in pediatric patients, and exploration of different dosing regimens using Monte Carlo PK/PD simulation. Blood samples were drawn around this dose and PK analysis was conducted using standard noncompartmental methods. Micafungin at 3 mg/kg dose was well tolerated in all patients. Measurable plasma concentrations were present in all cases at 48 hours. Half-life and clearance observed were comparable to previous pediatric PK data, with clearance being higher than adults as expected. Volume of distribution was higher in our patients compared to published pediatric data, likely because of a larger proportion of very young children in our study cohort. After correction for protein binding, concentrations at the end of the dosing interval during maintenance treatment remain above the minimum inhibitory concentration (MIC) of highly susceptible fungal pathogens. These data suggest that alternate day micafungin dosing, as described here, may provide an attractive alternative for antifungal prophylaxis in HSCT patients and merits further evaluation
A Novel Intermediate Alemtuzumab Schedule Optimizes the Incidences of Mixed Chimerism and Acute GVHD in Patients with HLH and XLP Undergoing Allogeneic HCT
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