Thrombotic complications associated with stem cell transplantation

Von Willebrand Factor and Platelet Levels before Conditioning Chemotherapy Indicate Bone Marrow Regeneration following Autologous Hematopoietic Stem Cell Transplantation

Autologous hematopoietic stem cell transplantation (HSCT) is often complicated by hemostatic and thrombotic events associated with endothelial cell injury. Thrombotic complications are affected by a disturbed balance between platelets, circulating von Willebrand factor (VWF), and its specific protease, ADAMTS13. HSCT-associated endothelial dysfunction, impaired hemostasis, and inflammation are interrelated processes, and research on the complex interplay of conditioning regimens from engraftment to bone marrow regeneration remains intensive. This prospective observational study comparing lymphoma and multiple myeloma (MM) patients who underwent autologous HSCT explored how platelet count, VWF level, ADAMTS13 activity, and C-reactive protein (CRP) level as potential markers (1) vary in response to therapy, (2) differ between the 2 groups, and (3) correlate with the remission state at 100 days after HSCT. We correlated the quantitative changes in platelet count and levels of VWF, ADAMTS13, and CRP with one another during HSCT and in the remission state in 45 patients with lymphoma and 59 patients with MM who underwent autologous HSCT between 2010 and 2013 at the University of Debrecen. Samples were collected at the start of conditioning chemotherapy, on the day of stem cell transplantation, and at 5, 11, and 100 days following HSCT. CRP levels peaked when platelet counts dropped to a minimum, and these changes were much more pronounced in the lymphoma group. VWF level was the highest, with lower ADAMTS13 activity, at platelet engraftment in both patient groups equally. Diagnostic evidence indicative of thrombotic complications was not found. In the lymphoma group, VWF level prior to conditioning had statistically significant correlations with platelet count, CRP level, and hemoglobin concentration at the time of bone marrow regeneration (P < .001) and during the remission state (P = .034). In the MM group, platelet count before conditioning was correlated with platelet count (P < .001) and white blood cell count (P = .012) at the time of bone marrow regeneration. The statistically significant correlation of the markers at the time of bone marrow regeneration with the preconditioning VWF levels in lymphoma and with the preconditioning platelet counts in MM might indicate the clinical significance of the bone marrow niches of arterioles and megakaryocytes, respectively, where the stem cells are located and regulated. Because preconditioning VWF levels are associated with remission after HSCT in lymphoma patients, VWF should be screened before conditioning, along with the markers used in HSCT protocols, to optimize personalized treatment and reduce therapeutic risks.

Case Report: Successful Treatment With Anti-C5 Monoclonal Antibody in a Japanese Adolescent Who Developed Thrombotic Microangiopathy After Autologous Bone Marrow Transplantation for Malignant Lymphoma

BACKGROUND

Transplant-associated thrombotic microangiopathy (TA-TMA) is a serious complication of bone marrow transplantation (BMT). Recently, abnormalities in the complement system have been identified in the pathogenesis of TA-TMA, and there are series of reports stating that anti-C5 monoclonal antibody (eculizumab) is effective in patients with high levels of the membrane attack complex (C5b-9).

CASE PRESENTATION

A 12-year-old boy underwent autologous BMT after receiving high-dose chemotherapy for malignant lymphoma. The patient was engrafted on day 19 after transplantation; however, hemolytic anemia and non-immune thrombocytopenia persisted, and haptoglobin decreased on day 46. Moreover, on day 83, the patient developed pulmonary hemorrhage, hypertension, severe proteinuria, hematuria, and acute kidney injury (AKI). Pulmonary bleeding stopped with daily platelet transfusion and hemostatic agents, but reappeared on day 100. Based on the presence of destruction of red blood cells, elevated lactate dehydrogenase levels, negative direct and indirect Coombs tests, normal ADAMTS13 levels, hemolytic anemia, non-immune thrombocytopenia, and AKI, the patient was diagnosed with systemic TA-TMA and we initiated plasma exchange (PE) and continuous hemodialysis for AKI. High C5b-9 levels were identified at the start of the series of PE, therefore we decided to administer eculizumab. After three courses of eculizumab, no pulmonary hemorrhage was observed, and anemia, thrombocytopenia, renal dysfunction, hematuria, and proteinuria all tended to improve. Three years after transplantation, the patient is alive and does not require eculizumab.

DISCUSSION

Eculizumab is a humanized monoclonal antibody that binds complement protein C5, preventing cleavage C5 and the formation of C5b-9. In this case, TA-TMA could not be controlled with PE alone. We therefore decided to use eculizumab relatively early based on the high C5b-9 level and could resolve the momentum of TA-TMA.

CONCLUSION

In previous reports, TA-TMA typically occurred in early post-allogeneic BMT of patients with lymphoma or in post-autologous BMT of patients with neuroblastoma and was treated with eculizumab. We here reported that eculizumab could be successful treatment for TA-TMA in post-autologous BMT of patient with lymphoma.

Thrombotic and hemorrhagic complications in children and young adult recipients of Hematopoietic Stem Cell Transplant (HSCT)

BACKGROUND

Overall incidence of hemostatic complications in pediatric recipients of Hematopoietic Stem Cell Transplant (HSCT) is scarcely studied. This retrospective review explored the incidence and underlying risk factors of bleeding and thrombotic complications in children.

PROCEDURE

Clinical characteristics, hemorrhagic events (HE), thrombotic events (TE) and follow up data were abstracted from medical records on patients aged <21 years undergoing HSCT during January 2000-June 2015.

RESULTS

From start of conditioning until last follow up, 238 pediatric patients were reviewed during this study. There were 16 symptomatic thrombotic complications in 15 patients, along with 13 major bleeding events. Incidence of HE or TE was higher in allogeneic HSCT compared to autologous HSCT (p = 0.02). Severe thrombocytopenia could not be identified as a major contributor to bleeding. All patients with HE had platelets between 20,000-50,000 × 10⁹/L, except one patient, who had platelets <20,000 × 10⁹/L. All patients with hemorrhagic cystitis (n = 7) had received cyclophosphamide (Cy). For patients with sinusoidal obstruction syndrome, conditioning included either busulfan (Bu)/Cy (n = 5), Cy with total body irradiation (n = 4), or thiotepa (n = 2). Among allogeneic HSCT recipients, 60% of HE and 92% with TE had underlying myeloid neoplasms. Graft versus Host disease contributed to both types of complications (p = 0.07), although not reaching statistical significance.

CONCLUSIONS

Allogeneic pediatric HSCT patients had higher overall risk of hemorrhagic or thrombotic complications compared to autologous recipients in this study. HSCT for myeloid malignancies was a risk factor for higher complications.

Phosphodiesterase III inhibitor attenuates rat sinusoidal obstruction syndrome through inhibition of platelet aggregation in Disse's space

BACKGROUND AND AIM

Sinusoidal obstruction syndrome (SOS) is a serious drug-induced liver injury. However, the pathophysiology of the disease remains unclear. This study investigated the effects of cilostazol (CZ), a phosphodiesterase III inhibitor, in a monocrotaline (MCT)-induced rat model of SOS.

METHODS

Male Wistar rats were administrated MCT to induce SOS. Rats were divided into control, MCT, and MCT + CZ groups. In the MCT + CZ group, CZ was administered at 48 h, 24 h, and 30 min prior to and 8 h and 24 h after MCT administration. The MCT group was treated with water instead of CZ. At 48 h after MCT administration, blood and liver samples were collected to assess biochemistry and liver histology. Expression of rat endothelial cell antigen, CD34, CD41, P-selectin, and caspase-3 in the liver were analyzed. Plasminogen activator inhibitor-1 (PAI-1) in hepatocytes was analyzed using western blotting and polymerase chain reaction.

RESULTS

In the MCT group, macroscopic findings showed a dark-red liver surface. Histological findings showed sinusoidal dilatation, coagulative necrosis of hepatocytes, and endothelial damage of the central vein. These changes were attenuated in the MCT + CZ group. Elevated serum transaminase and decreased platelet counts were observed in the MCT + CZ group compared with those in the MCT group. Treatment with CZ reduced MCT-induced damage to the liver sinusoidal endothelial cells, inhibited extravasated platelet aggregation, and suppressed hepatocyte apoptosis around the central vein. CZ attenuated hepatic PAI-1 protein and mRNA levels.

CONCLUSIONS

Cilostazol attenuated MCT-induced SOS by preventing damage to liver sinusoidal endothelial cells and extravasated platelet aggregation. Hepatic PAI-1 levels were suppressed with CZ treatment.

Successful Treatment of Transplantation-associated Atypical Hemolytic Uremic Syndrome With Eculizumab

We herein reported a 4-month-old boy with transplantation-associated atypical hemolytic uremic syndrome (TA-aHUS) who was successfully treated with eculizumab. The patient diagnosed with type 3 of familial hemophagocytic lymphohistiocytosis underwent cord blood transplantation. After transplantation, he developed TA-aHUS, but plasma exchanges were unsuccessful. We identified deletions in CFH-related gene 1 (del-CFHR1) by the multiplex ligation-dependent probe amplification testing procedure and CFH autoantibodies. Eculizumab has been administered to the patient, with a marked improvement being achieved in thrombocytopenia. He has been well except for the persistent microhematuria for a year after transplantation. Uncontrolled complement activation might be involved in the pathophysiology of TA-aHUS.

Graft Product for Autologous Peripheral Blood Stem Cell Transplantation Enhances Thrombin Generation and Expresses Procoagulant Microparticles and Tissue Factor

The beneficial effect of autologous peripheral blood stem cell transplantation (APBSCT) may be compromised by acute vascular complications related to hypercoagulability. We studied the impact of graft product on thrombin generation of normal plasma and the expression of tissue factor (TF) and procoagulant platelet-derived procoagulant microparticles (Pd-MPs) in samples of graft products. Graft products from 10 patients eligible for APBSCT were mixed with platelet-poor plasma (PPP) or platelet-rich plasma (PRP) from healthy volunteers and assessed for in vitro thrombin generation. In control experiments, thrombin generation was assessed in (1) PPP and PRP without any exogenous TF and/or procoagulant phospholipids, (2) PPP with the addition of TF (5 pM) and procoagulant phospholipids (4 μM), (3) in PRP with the addition of TF (5 pM). Graft products were assessed with Western blot assay for TF expression, with a specific clotting assay for TF activity and with flow cytometry assay for Pd-MPs. The graft product enhanced thrombin generation and its procoagulant activity was related to the presence of Pd-MPs and TF. The concentration of Pd-MPs in the graft product was characterized by a significant interindividual variability. The present study reveals the need for a thorough quality control of the graft products regarding their procoagulant potential.

A review of radiation countermeasures focusing on injury-specific medicinals and regulatory approval status: part III. Countermeasures under early stages of development along with 'standard of care' medicinal and procedures not requiring regulatory approval for use

PURPOSE

Terrorist attacks, with their intent to maximize psychological and economic damage as well as inflicting sickness and death on given targeted populations, are an ever-growing worldwide concern in government and public sectors as they become more frequent, violent, and sensational. If given the chance, it is likely that terrorists will use radiological or nuclear weapons. To thwart these sinister efforts, both physical and medical countermeasures against these weapons are currently being researched and developed so that they can be utilized by the first responders, military, and medical providers alike. This is the third article of a three-part series in which we have reviewed additional radiation countermeasures that are currently under early preclinical phases of development using largely animal models and have listed and discussed clinical support measures, including agents used for radiation-induced emesis, as well as countermeasures not requiring Food and Drug Administration approval.

CONCLUSIONS

Despite the significant progress that has been made in this area during the last several years, additional effort is needed in order to push promising new agents, currently under development, through the regulatory pipeline. This pipeline for new promising drugs appears to be unreasonably slow and cumbersome; possible reasons for this inefficiency are briefly discussed. Significant and continued effort needs to be afforded to this research and development area, as to date, there is no approved radioprotector that can be administered prior to high dose radiation exposure. This represents a very significant, unmet medical need and a significant security issue. A large number of agents with potential to interact with different biological targets are under development. In the next few years, several additional radiation countermeasures will likely receive Food and Drug Administration approval, increasing treatment options for victims exposed to unwanted ionizing irradiation.

Diagnostic Utility of Complement Immunohistochemical Studies in Post-Stem Cell Transplant Intestinal Thrombotic Microangiopathy: Case Report

Thrombotic complications are a significant source of morbidity and mortality following hematopoietic stem cell transplants. Among them, transplant-associated thrombotic microangiopathy (TA-TMA) is a well-recognized syndrome that can affect various organ systems. Its etiology is related to endothelial injury accompanied by complement activation. As many of the signs and symptoms of the disease are also encountered in other complications following hematopoietic stem cell transplant, it can often be difficult to establish the diagnosis based on clinical data alone. Histopathologic examination of various tissues may be performed in difficult cases. However, the microscopic features of TA-TMA also overlap with those seen in other posttransplant complications, suggesting a need for additional tests to help in diagnosis. Here we describe a patient who presented with hemolytic anemia, thrombocytopenia, renal and neurological impairment, who also developed significant bloody diarrhea. Flexible sigmoidoscopy with biopsies was performed to determine the exact etiology of his gastrointestinal bleed. A diagnosis of intestinal TA-TMA was established with the use of immunohistochemical stains for complement components C5b-9 and C4d. This is the first report that highlights the utility of complement staining on histologic sections from digestive samples to render a definitive diagnosis of intestinal TA-TMA.

High-dose corticosteroid associated with catheter-related thrombosis after allogeneic hematopoietic stem cell transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are at an increased risk of thrombotic complications, most of which are catheter-related and present a substantial challenge. The incidence of CRT varies considerably depending on clinical factors. However, the underlying pathogenesis and risk factors remain unclear.

METHODS

We performed a retrospective nested case-control study in patients following allo-HSCT. Thrombotic episodes were diagnosed based on the clinical suspicion of the physician (pain, swelling, etc.) with subsequent CVC or PICC thrombosis confirmed via duplex ultrasound. Cases with CRT and controls were matched for time of HSCT, age at HSCT, donor source and type of insertion (CVCs or PICC).

RESULTS

During the 8-year period, catheters were placed in 2896 patients, with a total of 40 patients (1.38%) developed CRT, among which 11 were associated with CVCs and 29 were associated with PICCs. The median duration from catheter insertion to thrombosis was 97days. Despite reports of an association between thrombosis and infection, central line-associated bloodstream infection was comparable between groups. No significant differences were noted in terms of primary disease, donor type, conditioning regimen or catheter type between the cases and controls. A multivariate regression analysis identified high-dose corticosteroids as independent risk factors for the development of CRT. CRT seems to negatively affect prognosis in allo-HSCT patients.

CONCLUSION

In conclusion, we demonstrate that the use of high-dose corticosteroids is correlated with the onset of CRT. However, the efficacy and safety of thromboprophylaxis in this population require further investigation.

Renal complications in chronic lymphocytic leukemia and monoclonal B-cell lymphocytosis: the Mayo Clinic experience

While the renal complications of plasma cell dyscrasia have been well-described, most information in patients with chronic lymphocytic leukemia and monoclonal B-cell lymphocytosis is derived from case reports. This is a retrospective analysis of patients with chronic lymphocytic leukemia or monoclonal B-cell lymphocytosis who underwent kidney biopsy for renal insufficiency and/or nephrotic syndrome. Between January 1995 and June 2014, 49 of 4,024 (1.2%) patients with chronic lymphocytic leukemia (n=44) or monoclonal B-cell lymphocytosis (n=5) had a renal biopsy: 34 (69%) for renal insufficiency and 15 (31%) for nephrotic syndrome. The most common findings on biopsy were: membranoproliferative glomerulonephritis (n=10, 20%), chronic lymphocytic leukemia interstitial infiltration as primary etiology (n=6, 12%), thrombotic microangiopathy (n=6, 12%), and minimal change disease (n=5, 10%). All five membranoproliferative glomerulonephritis patients treated with rituximab, cyclophosphamide and prednisone-based regimens had recovery of renal function compared to 0/3 patients treated with rituximab with or without steroids. Chronic lymphocytic leukemia infiltration as the primary cause of renal abnormalities was typically observed in relapsed/refractory patients (4/6). Thrombotic microangiopathy primarily occurred as a treatment-related toxicity of pentostatin (4/6 cases), and resolved with drug discontinuation. All cases of minimal change disease resolved with immunosuppressive agents only. Renal biopsy plays an important role in the management of patients with chronic lymphocytic leukemia or monoclonal B-cell lymphocytosis who develop renal failure and/or nephrotic syndrome.

Non-infectious respiratory disease in non-HIV immunocompromised patients

This review summarizes current knowledge regarding frequently encountered non-infectious respiratory complications in adult immunocompromised hosts (excluding those with human immunodeficiency virus (HIV) infection). In particular it will discuss complications of transplantation and of primary immunodeficiencies.

New approaches to radiation protection

Radioprotectors are compounds that protect against radiation injury when given prior to radiation exposure. Mitigators can protect against radiation injury when given after exposure but before symptoms appear. Radioprotectors and mitigators can potentially improve the outcomes of radiotherapy for cancer treatment by allowing higher doses of radiation and/or reduced damage to normal tissues. Such compounds can also potentially counteract the effects of accidental exposure to radiation or deliberate exposure (e.g., nuclear reactor meltdown, dirty bomb, or nuclear bomb explosion); hence they are called radiation countermeasures. Here, we will review the general principles of radiation injury and protection and describe selected examples of radioprotectors/mitigators ranging from small-molecules to proteins to cell-based treatments. We will emphasize agents that are in more advanced stages of development.

Cryopreserved stem cell products containing dimethyl sulfoxide lead to activation of the coagulation system without any impact on engraftment

BACKGROUND

Dimethyl sulfoxide (DMSO) is extensively used as a cryoprotectant in stem cell preservation. Little is known on direct hemostatic changes in recipients of hematopoietic stem cell transplantation (HSCT), immediately after DMSO administration. The objectives of the current study were to measure hemostatic changes during HSCT.

STUDY DESIGN AND METHODS

In this prospective analysis, changes in plasma biomarkers, platelets (PLTs), or endothelial cells (D-dimers, thrombin-antithrombin complex [TAT], microparticle activity as thrombin-generation potential [MPA], whole blood aggregation, von Willebrand factor) were measured before and immediately after HSCT. Furthermore, associations with clinical complications were recorded.

RESULTS

A total of 54 patients were included in the study. Mean MPA and TAT increased significantly immediately after HSCT, returning to baseline the day after the procedure (p<0.01). No significant differences in engraftment for neutrophils and PLTs were found in patients presenting a high increase of TAT or MPA compared with those presenting with a smaller increase. Patients with a high increase in TAT and MPA had received a greater number of total mononucleated cells (p<0.001) and higher transplant volumes (p=0.002).

CONCLUSIONS

Infusion of stem cells containing DMSO reversibly activated coagulation, measured as thrombin generation. This finding was not associated with acute adverse events and did not influence engraftment. Further studies are needed to compare variable DMSO concentrations as well as DMSO-free products, to better address the influence of DMSO on hemostasis.

Liver abnormalities in the immunosuppressed

The immunosuppressed state may arise due to medical illness or drug therapy, which can result in a diverse array of liver derangements. This article discusses the commonly-encountered immunosuppressed conditions and the associated specific liver diseases. Due to the frequency of blood-borne viral disease globally, viral hepatitis (hepatitis B and C) during chemotherapy, transplantation and the increasingly utilised biological therapies for autoimmune disorders is discussed. An overview of human immunodeficiency virus co-infection with hepatitis B and C is provided. This article aims to highlight the variety of liver diseases which can occur in clinically relevant, particularly iatrogenic, immunosuppressed conditions, and summarise learning and practice points for clinicians. Recognition and prevention of viral liver disease is crucial and early involvement of experts prior to administration of immunosuppressive therapy is advised.