Human mesenchymal stromal cells inhibit platelet activation and aggregation involving CD73-converted adenosine.

BACKGROUND: Mesenchymal stromal cells (MSCs) are promising cell therapy candidates. Clinical application is considered safe. However, minor side effects have included thromboembolism and instant blood-mediated inflammatory reactions suggesting an effect of MSC infusion on hemostasis. Previous studies focusing on plasmatic coagulation as a secondary hemostasis step detected both procoagulatory and anticoagulatory activities of MSCs. We now focus on primary hemostasis and analyzed whether MSCs can promote or inhibit platelet activation. METHODS: Effects of MSCs and MSC supernatant on platelet activation and function were studied using flow cytometry and further platelet function analyses. MSCs from bone marrow (BM), lipoaspirate (LA) and cord blood (CB) were compared to human umbilical vein endothelial cells or HeLa tumor cells as inhibitory or activating cells, respectively. RESULTS: BM-MSCs and LA-MSCs inhibited activation and aggregation of stimulated platelets independent of the agonist used. This inhibitory effect was confirmed in diagnostic point-of-care platelet function analyses in platelet-rich plasma and whole blood. Using inhibitors of the CD39-CD73-adenosine axis, we showed that adenosine produced by CD73 ectonucleotidase activity was largely responsible for the LA-MSC and BM-MSC platelet inhibitory action. With CB-MSCs, batch-dependent responses were obvious, with some batches exerting inhibition and others lacking this effect. CONCLUSIONS: Studies focusing on plasmatic coagulation suggested both procoagulatory and anticoagulatory activities of MSCs. We now show that MSCs can, dependent on their tissue origin, inhibit platelet activation involving adenosine converted from adenosine monophosphate by CD73 ectonucleotidase activity. These data may have strong implications for safety and risk/benefit assessment regarding MSCs from different tissue sources and may help to explain the tissue protective mode of action of MSCs. The adenosinergic pathway emerges as a key mechanism by which MSCs exert hemostatic and immunomodulatory functions.

Performance assessment and benchmarking of autologous peripheral blood stem cell collection with two different apheresis devices.

BACKGROUND: Collection of peripheral blood stem cells (PBSCs) for autologous transplantation is a well-established process. As a new generation of leukapheresis (LP) machines has been launched, measures of benchmarking and quality control need to be defined in order to ensure consistent collection performance. OBJECTIVES: The goal of this project was to establish and evaluate a benchmarking system for autologous PBSC collection. METHODS: This retrospective study evaluated PBSC collection data of 198 patients with symptomatic multiple myeloma in first-line therapy who underwent LP in 2013 and 2014 at our institution. Half the patients in 2014 were assigned randomly to undergo LP with the new Terumo BCT Spectra Optia (Terumo BCT, Garching, Germany), while the COBE Spectra (Terumo BCT) was used in all other cases. In 2014, we implemented a previously described formula for predicting daily CD34+ cell collection. As a benchmark, we developed the performance ratio: collected/predicted CD34+ cells. RESULTS: There was no significant difference in the number of collected CD34+ cells, the collection efficiency (collected/processed CD34+ cells) and performance ratio between the two collection devices and between LP procedures in 2013 and 2014. CONCLUSIONS: We present a comprehensive benchmarking tool that is easy to implement, requires minimal expense and allows specific adjustment of LP parameters for optimisation of LP performance. With this approach, we could confirm the equal efficiency of the two compared apheresis systems.

Prognostic impact of progression to induction chemotherapy and prior paclitaxel therapy in patients with germ cell tumors receiving salvage high-dose chemotherapy in the last 10 years: a study of the European Society for Blood and Marrow Transplantation Solid Tumors Working Party.

Little is known about the prognostic impact of prior paclitaxel therapy and response to induction chemotherapy defined as the regimen preceding high-dose chemotherapy (HDCT) for the salvage therapy of advanced germ cell tumors. Twenty European Society for Blood and Marrow Transplantation centers contributed data on patients treated between 2002 and 2012. Paclitaxel used in either prior lines of therapy or in induction-mobilization regimens was considered. Multivariable Cox analyses of prespecified factors were undertaken on PFS and overall survival (OS). As of October 2013, data for 324 patients had been contributed to this study. One hundred and ninety-two patients (59.3%) had received paclitaxel. Sixty-one patients (19%) had a progression to induction chemotherapy, 234 (72%) a response (29 (9%) missing or granulocyte colony-stimulating factor without chemotherapy). Both progression to induction chemotherapy and prior paclitaxel were significantly associated with shorter OS univariably (P<0.001 and P=0.032). On multivariable analysis from the model with fully available data (N=216) progression to induction was significantly prognostic for PFS and OS (P=0.003), but prior paclitaxel was not (P=0.674 and P=0.739). These results were confirmed after multiple imputation of missing data. Progression to induction chemotherapy could be demonstrated as an independent prognostic factor, in contrast to prior paclitaxel.

The influence of rituximab, high-dose therapy followed by autologous stem cell transplantation, and age in patients with primary CNS lymphoma.

For patients with diffuse large B cell lymphoma without the involvement of the CNS, the addition of rituximab to standard chemotherapy has significantly improved survival. In this single-center, retrospective analysis, a total of 81 primary CNS lymphoma (PCNSL) patients treated in our institution between 2000 and 2011 were included. Beside first-line chemotherapy with or without rituximab, we evaluated the impact of age (≤/>60 years), autologous stem cell transplantation (ASCT +/-), and other factors upon overall survival (OS) and progression-free survival (PFS). In patients treated with rituximab (n = 27), 3-year OS was 77.8 % (95 % confidence interval (CI) 62-93 %). In contrast, in patients treated without rituximab (n = 52), 3-year OS was only 39.9 % (CI 27-53 %, Fig. 1). The difference in OS was significant in the univariate (p = 0.002) as well as in the multivariate analysis (p = 0.049, hazard ratio (HR) = 0.248). Patients ≤60 years of age (n = 28) had a 3-year OS of 78.2 % (CI 63-94 %); in patients >60 years (n = 51), 3-year OS was 38.7 % (CI 25-52 %). Patients who received high-dose therapy and ASCT had a 3-year OS of 85.2 % (CI 72-99 %), and 65.1 % were alive up to the time of analysis (range 9-131 months). Without ASCT, median OS was only 16 months (CI 11-21) and 3-year OS was 35.2 % (CI 22-48 %). Age and ASCT were significantly associated with better OS in univariate (p = 0.002 and p < 0.001) as well in multivariate analysis (p = 0.004, HR = 0.023 and p = 0.001, HR = 0.014). Rituximab treatment, ASCT, and age are independent prognostic factors for OS in the first-line treatment of PCNSL.

Mesenchymal stromal cells inhibit proliferation of virus-specific CD8(+) T cells.

Mesenchymal stromal cells (MSCs) possess broad immunomodulatory capacities that are currently investigated for potential clinical application in treating autoimmune disorders. Third-party MSCs suppress alloantigen-induced proliferation of peripheral blood mononuclear cells providing the rationale for clinical use in graft-versus-host disease (GvHD). We confirmed that MSCs strongly inhibited proliferation of CD8(+) T cells in a mixed lymphocyte reaction. However, MSCs also suppressed proliferation of T cells specifically recognizing cytomegalovirus (CMV) and influenza virus. Inhibition was dose dependent, but independent of the culture medium. MSCs inhibited proliferation of specific CD8(+) T cells and the release of IFN-γ by specific CD8(+) T cells for immunodominant HLA-A2- and HLA-B7- restricted antigen epitopes derived from CMV phosphoprotein 65 and influenza matrix protein. This is in contrast to a recently reported scenario where MSCs exert differential effects on alloantigen and virus-specific T cells potentially having an impact on surveillance and prophylaxis of patients treated by MSCs.

Autologous haematopoietic stem cell mobilisation in multiple myeloma and lymphoma patients: a position statement from the European Group for Blood and Marrow Transplantation.

Autologous haematopoietic SCT with PBSCs is regularly used to restore BM function in patients with multiple myeloma or lymphoma after myeloablative chemotherapy. Twenty-eight experts from the European Group for Blood and Marrow Transplantation developed a position statement on the best approaches to mobilising PBSCs and on possibilities of optimising graft yields in patients who mobilise poorly. Choosing the appropriate mobilisation regimen, based on patients' disease stage and condition, and optimising the apheresis protocol can improve mobilisation outcomes. Several factors may influence mobilisation outcomes, including older age, a more advanced disease stage, the type of prior chemotherapy (e.g., fludarabine or melphalan), prior irradiation or a higher number of prior treatment lines. The most robust predictive factor for poor PBSC collection is the CD34(+) cell count in PB before apheresis. Determination of the CD34(+) cell count in PB before apheresis helps to identify patients at risk of poor PBSC collection and allows pre-emptive intervention to rescue mobilisation in these patients. Such a proactive approach might help to overcome deficiencies in stem cell mobilisation and offers a rationale for the use of novel mobilisation agents.

Consolidation with high-dose chemotherapy and stem cell support for responding patients with metastatic soft tissue sarcomas: prospective, single-institutional phase II study.

Prognosis of patients with metastatic soft tissue sarcoma remains poor. Whether high-dose chemotherapy with stem cell support improves the long-term outcome for these patients is debatable. We present a prospective, single-institutional phase II study that enrolled 34 soft tissue sarcoma patients with advanced and/or metastatic disease. After four courses of chemotherapy consisting of doxorubicin and ifosfamide, responding patients in at least partial response (PR) were treated with high-dose chemotherapy (n=9); all other patients continued chemotherapy for two more cycles. After standard chemotherapy, PR (n=10), stable disease (SD, n=6) and progressive disease (PD, n=14) were attained for the evaluable patients. Twenty-nine patients died and five are alive with the disease. Median PFS was 11.6 months (range 8-15) for patients treated with high-dose chemotherapy (n=9) vs 5.6 months (range 0-19) for patients treated with standard chemotherapy. Median OS was 23.7 months (range 12-34) vs 10.8 months (range 0-39), respectively. The subgroup of patients treated with high-dose chemotherapy gained significant survival benefit. Nevertheless, high-dose chemotherapy as a possible consolidation strategy remains highly investigational.

[Positron emission tomography as a tool for early prediction of therapy outcome in soft tissue sarcoma]. / Positronen-Emissions-Tomographie zur Vorhersage des Therapieansprechens bei Weichteilsarkomen.

BACKGROUND AND OBJECTIVE: We used 2-deoxy-2-[(18)F] fluoro-D-glucose (FDG) positron emission tomography (PET) to evaluate the FDG uptake in patients with soft tissue sarcoma (STS). Treatment effect was assessed with regard to prediction of therapy outcome. PATIENTS AND METHODS: This evaluation includes 35 patients with high risk STS receiving chemotherapy consisting of doxorubicin and ifosfamide (AI-G regimen) or etoposide, ifosfamide and doxorubicin (EIA regimen). Patients were examined using PET prior to onset of therapy and after completion of the first cycle of AI-G and after two cycles of EIA chemotherapy, respectively. Restaging according to RECIST was performed after six cycles of AI-G or four cycles of EIA chemotherapy and served as reference. RESULTS: Clinical outcome of 35 evaluable patients was as follows: two patients with no evidence of disease (NED), eleven with partial remission (PR), 17 with stable disease (SD), and five patients with progressive disease (PD). A difference regarding progression-free survival for patients with a decrease in SUV (responders) in comparison to patients with an increase or stable SUV (non-responders) could be demonstrated (p = 0.0943). CONCLUSION: On the basis of these data, prediction of chemo-sensitivity of the tumour and moreover of the therapy outcome might be possible.

Evaluation of the Murex CMV DNA Hybrid Capture assay (version 2.0) for early diagnosis of cytomegalovirus infection in recipients of an allogeneic stem cell transplant.

Early diagnosis of CMV infection based on sensitive diagnostic assays has helped to reduce CMV-related mortality after allogeneic stem cell transplantation (SCT). In this study, the commercialized Murex CMV DNA Hybrid Capture assay (version 2.0) (HCS) was prospectively compared to an in-house CMV-DNA PCR assay from whole blood in patients after allogeneic stem cell transplantation. Overall, a high concordance between HCS and PCR was documented (kappa = 0.686; n = 385). The HCS assay was found to be as sensitive as the PCR indicating active CMV infection at a median of 35 and 34 days after transplantation, respectively. None of the HCS-negative patients developed CMV-related symptoms (negative predictive value 100%). Declining CMV DNA load in the blood was found to be an indicator for effective antiviral therapy, whereas persistence of a high viral load was associated with fatal CMV disease. In conclusion, the Hybrid Capture CMV DNA assay (v 2.0) allows early diagnosis of CMV infection after allogeneic SCT and assessment of the efficacy of antiviral therapy.