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Concerns about competition between pollinators are predicated on the assumption of floral resource limitation. Floral resource limitation, however, is a complex phenomenon involving the interplay of resource production by plants, resource demand by pollinators, and exogenous factors-like weather conditions-that constrain both plants and pollinators. In this study, we examined nectar limitation during the mass flowering of rosaceous fruit trees in early spring. Our study was set in the same region as a previous study that found severe nectar limitation in summer grasslands. We used this seasonal contrast to evaluate two alternative hypotheses concerning the seasonal dynamics of floral resource limitation: either (H1) rates of resource production and consumption are matched through seasonal time to maintain a consistent degree of resource limitation, or (H2) a mismatch of high floral resource production and low pollinator activity in early spring creates a period of relaxed resource limitation that intensifies later in the year. We found generally much lower depletion in our spring study compared to the near 100% depletion found in the summer study, but depletion rates varied markedly through diel time and across sampling days, with afternoon depletion rates sometimes exceeding 80%. In some cases, there were also pronounced differences in depletion rates across simultaneously sampled floral species, indicating different degrees of nectar exploitation. These findings generally support the seasonal mismatch hypothesis (H2) but underscore the complex contingency of nectar depletion. The challenge of future work is to discern how the fluctuation of resource limitation across diel, inter-diel, and seasonal time scales translates into population-level outcomes for pollinators., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Hematopoietic stem cell transplantation (HSCT) from haploidentical donors is a viable option for patients lacking HLA-matched donors. Here we report the results of a prospective multicenter phase I/II trial of transplantation of TCRαβ and CD19-depleted peripheral blood stem cells from haploidentical family donors after a reduced-intensity conditioning with fludarabine, thiotepa, and melphalan. Thirty pediatric and 30 adult patients with acute leukemia (n = 43), myelodysplastic or myeloproliferative syndrome (n = 6), multiple myeloma (n = 1), solid tumors (n = 6), and non-malignant disorders (n = 4) were enrolled. TCR αβ/CD19-depleted grafts prepared decentrally at six manufacturing sites contained a median of 12.1 × 10 6 CD34 + cells/kg and 14.2 × 10 3 TCRαβ + T-cells/kg. None of the patients developed grade lll/IV acute graft-versus-host disease (GVHD) and only six patients (10%) had grade II acute GVHD. With a median follow-up of 733 days 36/60 patients are alive. The cumulative incidence of non-relapse mortality at day 100, 1 and 2 years after HSCT was 5%, 15%, and 17% for all patients, respectively. Estimated probabilities of overall and disease-free survival at 2 years were 63% and 50%, respectively. Based on these promising results in a high-risk patient cohort, haploidentical HSCT using TCRαβ/CD19-depleted grafts represents a viable treatment option., (© 2021. The Author(s).)

The efficacy of immunotherapies in cancer treatment becomes more and more apparent not only in different solid tumors but also in hematological malignancies. However, in acute myeloid leukemia (AML), mechanisms to increase the efficacy of immunotherapeutic approaches have to be further elucidated. Targeting leukemic progenitor and stem cells (LPC/LSC) by specific CTL, for instance, in an adjuvant setting or in minimal residual disease, might be an option to prevent relapse of AML or to treat MRD. Therefore, we investigated the influence of immune checkpoint inhibitors on LAA-specific immune responses by CTL against leukemic myeloid blasts and colony-forming cells including leukemic progenitor cells (CFC/LPC). In functional immunoassays like CFU/CFI (colony-forming units/immunoassays) and ELISpot analysis, we detected specific LAA-directed immune responses against CFC/LPC that are postulated to be the source population of relapse of the disease. The addition of nivolumab (anti-PD-1) significantly increases LAA-directed immune responses against CFC/LPC, no effect is seen when ipilimumab (anti-CTLA-4) is added. The combination of ipilimumab and nivolumab does not improve the effect compared to nivolumab alone. The anti-PD1-directed immune response correlates to PD-L1 expression on progenitor cells. Our data suggest that immunotherapeutic approaches have the potential to target malignant CFC/LPC and anti-PD-1 antibodies could be an immunotherapeutic approach in AML. Moreover, combination with LAA-directed vaccination strategies might also open interesting application possibilities.

Background: Many data are available on expansion protocols for mesenchymal stromal cells (MSCs) for both experimental settings and manufacturing for clinical trials. However, there is a lack of information on translation of established protocols for Good Manufacturing Practice (GMP) from validation to manufacturing for clinical application. We present the validation and translation of a standardized pre-clinical protocol for isolation and expansion of MSCs for a clinical trial for reconstitution of alveolar bone., Methods: Key parameters of 22 large-scale expansions of MSCs from bone marrow (BM) for validation were compared with 11 expansions manufactured for the clinical trial "Jaw bone reconstruction using a combination of autologous mesenchymal stromal cells and biomaterial prior to dental implant placement (MAXILLO1)" aimed at reconstruction of alveolar bone., Results: Despite variations of the starting material, the robust protocol led to stable performance characteristics of expanded MSCs. Manufacturing of the autologous advanced therapy medicinal product MAXILLO-1-MSC was possible, requiring 21 days for each product. Transport of BM aspirates and MSCs within 24 h was guaranteed. MSCs fulfilled quality criteria requested by the national competent authority. In one case, the delivered MSCs developed a mosaic in chromosomal finding, showing no abnormality in differentiation capacity, growth behavior or surface marker expression during long-term culture. The proportion of cells with the mosaic decreased in long-term culture and cells stopped growth after 38.4 population doublings., Conclusions: Clinical use of freshly prepared MSCs, manufactured according to a standardized and validated protocol, is feasible for bone regeneration, even if there was a long local distance between manufacturing center and clinical site. Several parameters, such as colony forming units fibroblasts (CFU-F), percentage of CD34+ cells, cell count of mononuclear cells (MNCs) and white blood cells (WBCs), of the BM may serve as a predictive tool for the yield of MSCs and may help to avoid unnecessary costs for MSC manufacturing due to insufficient cell expansion rates., (Copyright © 2019 International Society for Cell and Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Background and Objectives: Mobilization of CD34 + cells by stimulation with G-CSF shows considerable variation across stem cell donors. Upfront prediction of CD34 + cell counts in peripheral blood based on easily available steady-state parameters would be helpful for the planning of apheresis and stem cell transplantation. Commonly accepted steady-state predictors for the mobilization are gender, body mass index and platelet count. The aim of the study was the identification of novel predictors that might influence mobilization efficacy and to create a model for the prediction of stem cell mobilization., Methods: A total of 333 healthy stem cell donors who donated peripheral stem cells in our institution were retrospectively analysed. All available data before stem cell mobilization with G-CSF were included in the database. Primary end-point was CD34 + cell count before the first apheresis., Results: In this cohort cholinesterase, differential blood cell counts including platelets, gender and body mass index were significantly correlated with CD34 + cell count. G-CSF dose per lean body weight showed a significant correlation with mobilization efficacy in women but not in men. A multivariate analysis identified gender, cholinesterase and platelet and red cell count as main predictors of mobilization. Red cell count showed a strong gender dependence, with higher predictive value in females., Conclusion: The counts of eosinophils, platelets, red cells, cholinesterase and gender are the most important predictors of CD34 + cell mobilization in our deduced models. The red cell count as a predictor for mobilization showed a differential gender dependence., (© 2019 International Society of Blood Transfusion.)

T cell responses against malignant cells play a major role in maintaining remission and prolonging overall survival in patients after allogeneic stem cell transplantation and donor lymphocyte infusion (DLI) due to graft-versus-leukemia effect. For better characterization of the T cell responses, we assessed frequency and diversity of leukemia-associated antigen (LAA)-specific cytotoxic T cells using ELISpot and pMHC multimer assays and analyzed the frequency of regulatory T cells (Treg) as well as cytokine profiles before/after DLI. The data were correlated to the clinical course of patients. Significantly more LAA-derived T cell epitopes (p = 0.02) were recognized in clinical responders (R) when compared to nonresponders (NR). In addition, pMHC multimer-based flow cytometry showed a significantly higher frequency of LAA-specific T cells in R versus NR. The frequency of Treg in R decreased significantly (p = 0.008) while keeping stable in NR. No differences in T cell subset analysis before/after DLI were revealed. Clinical responders were correlated to specific immune responses and all clinical responders showed an increase of specific immune responses after DLI. Cytokine assays using enzyme-linked immunosorbent assay showed a significant increase of IL-4 after DLI. Taken together, an increase of specific CTL responses against several LAA after DLI was detected. Moreover, this study suggests that enhanced LAA diversity in T cell responses as well as decreasing numbers of Treg contribute to clinical outcome of patients treated with DLI., (© 2018 UICC.)

Purpose: Clonal hematopoiesis of indeterminate potential (CHIP) occurs in the blood of approximately 20% of older persons. CHIP is linked to an increased risk of hematologic malignancies and of all-cause mortality; thus, the eligibility of stem-cell donors with CHIP is questionable. We comprehensively investigated how donor CHIP affects outcome of allogeneic hematopoietic stem-cell transplantation (HSCT)., Methods: We collected blood samples from 500 healthy, related HSCT donors (age ≥ 55 years) at the time of stem-cell donation for targeted sequencing with a 66-gene panel. The effect of donor CHIP was assessed on recipient outcomes, including graft-versus-host disease (GVHD), cumulative incidence of relapse/progression (CIR/P), and overall survival (OS)., Results: A total of 92 clonal mutations with a median variant allele frequency of 5.9% were identified in 80 (16.0%) of 500 donors. CHIP prevalence was higher in donors related to patients with myeloid compared with lymphoid malignancies (19.2% v 6.3%; P ≤ .001). In recipients allografted with donor CHIP, we found a high cumulative incidence of chronic GVHD (cGVHD; hazard ratio [HR], 1.73; 95% CI, 1.21 to 2.49; P = .003) and lower CIR/P (univariate: HR, 0.62; 95% CI, 0.40 to 0.97; P = .027; multivariate: HR, 0.63; 95% CI, 0.41 to 0.98; P = .042) but no effect on nonrelapse mortality. Serial quantification of 25 mutations showed engraftment of 24 of 25 clones and disproportionate expansion in half of them. Donor-cell leukemia was observed in two recipients. OS was not affected by donor CHIP status (HR, 0.88; 95% CI, 0.65 to 1.321; P = .434)., Conclusion: Allogeneic HSCT from donors with CHIP seems safe and results in similar survival in the setting of older, related donors. Future studies in younger and unrelated donors are warranted to extend these results. Confirmatory studies and mechanistic experiments are warranted to challenge the hypothesis that donor CHIP might foster cGVHD development and reduce relapse/progression risk.

Rationale: Patients receiving an allogeneic stem cell graft from cytomegalovirus (CMV) seronegative donors are particularly prone to CMV reactivation with a high risk of disease and mortality. Therefore we developed and manufactured a novel vaccine and initiated a clinical phase I trial with a CMV phosphoprotein 65 (CMVpp65)-derived peptide. Methods: Ten patients after allogeneic stem cell transplantation received four vaccinations at a biweekly interval. All patients were monitored for CMVpp65 antigenemia. Flow cytometry for CMV-specific CD8 + and γδ T cells as well as neutralizing anti-CMV antibodies were correlated to clinical parameters. Results: The vaccination was well tolerated. Seven of nine patients cleared CMVpp65 antigenemia after four vaccinations and are still free from antigenemia to this day. Two patients with CMV reactivation showed persisting CMV antigenemia. One patient received prophylactic vaccination and did not develop antigenemia. An increase of up to six-fold in frequency of both CMV-specific CD8 + T cells and/or Vδ2negative γδ T cells was detected. Titers of neutralizing antibodies increased up to the tenfold. Humoral and cellular immune responses correlated with clearance of CMV. Conclusion: In summary, CMVpp65 peptide vaccination for patients after allogeneic stem cell transplantation at high risk for CMV reactivation was safe, well tolerated and clinically encouraging. A study in solid-organ transplant patients is ongoing., Competing Interests: Competing Interests: J.K. is inventor of multiple patents dealing with γδ TCRs and co-founder as well as chief scientific officer (CSO) of Gadeta (http://www.gadeta.nl/). The other authors have declared that no competing interest exists.

Background: Biosimilar granulocyte-colony-stimulating factors (G-CSFs) have been available in the European Union since 2008, and Sandoz' biosimilar filgrastim was approved in the United States in March 2015 for all of the reference product's indications except acute radiation syndrome. Biosimilar G-CSFs have been largely embraced by the medical community, except for some reservations about healthy-donor stem cell mobilization, for which use outside of clinical studies was cautioned against by some members of the scientific community., Study Design and Methods: In a two-center safety surveillance study (National Clinical Trial NCT01766934), 245 healthy volunteer stem cell donors were enrolled. Of 244 donors who began mobilization with twice-daily Sandoz biosimilar filgrastim, 242 received a full (n = 241) or partial (n = 1) course of G-CSF and underwent apheresis. Efficacy and safety were assessed and are reported here., Results: Biosimilar filgrastim was accompanied by the typical G-CSF class-related adverse effects of expected frequency and severity. Median mobilization for CD34-positive stem cells was 97/µL (range, 20-347/µL); after one apheresis (91%) or two aphereses (9%) from all but three donors (1.2%), cell doses in excess of the typical 4 × 10 6 CD34-positive cells/kg of the recipient had been collected (range, 3-52 × 10 6 /kg). Biochemical and hematologic alterations were consistent with previous reports; all had normalized by the first follow-up 1 month after mobilization. Stem cell products engrafted with typical probability and kinetics for G-CSF-mobilized stem cell products., Conclusion: These data support the use of biosimilar filgrastim for healthy-donor stem cell mobilization as safe and effective., (© 2016 The Authors. Transfusion published by Wiley Periodicals, Inc. on behalf of AABB.)

Simple stress or necrotic cell death with subsequent release of damage-associated molecular patterns (DAMPs) is a characteristic feature of most advanced tumors. DAMPs within the tumor microenvironment stimulate tumor-associated cells, including dendritic cells and mesenchymal stromal cells (MSCs). The presence of tumor-infiltrating MSCs is associated with tumor progression and metastasis. Oxidized necrotic material loses its stimulatory capacity for MSCs. As a DAMP, S100A4 is sensitive to oxidation whereas uric acid (UA) acts primarily as an antioxidant. We tested these two biologic moieties separately and in combination for their activity on MSCs. Similar to necrotic tumor material, S100A4 and UA both dose-dependently induced chemotaxis of MSCs with synergistic effects when combined. Substituting for UA, alternative antioxidants (vitamin C, DTT, and N-acetylcysteine) also enhanced the chemotactic activity of S100A4 in a synergistic manner. This emphasizes the reducing potential of UA being, at least in part, responsible for the observed synergy. With regard to MSC proliferation, both S100A4 and UA inhibited MSCs without altering survival or inducing differentiation toward adipo-, osteo-, or chondrocytes. In the presence of S100A4 or UA, MSCs gained an immunosuppressive capability and stably induced IL-10- and IDO-expressing lymphocytes that maintained their phenotype following proliferation. We have thus demonstrated that both S100A4 and UA act as DAMPs and, as such, may play a critical role in promoting some aspects of MSC-associated immunoregulation. Our findings have implications for therapeutic approaches targeting the tumor microenvironment and addressing the immunosuppressive nature of unscheduled cell death within the tumor microenvironment., (Copyright © 2014 by The American Association of Immunologists, Inc.)

Background: In patients with acute myocardial infarction (AMI), the number of transplanted autologous bone-marrow cells (BMC) has been linked to improvement in left ventricular ejection fraction (LVEF). Complete obstruction of myocardial microvasculature is indicated by microvascular obstruction (MO) in cardiac magnetic resonance imaging (CMR). We analyzed whether the number of transplanted cells and presence of MO were associated with improved LVEF in the double-blind, placebo-controlled, randomized intracoronary Stem Cell therapy in patients with Acute Myocardial Infarction (SCAMI) trial., Methods and Results: Patients (N = 42) received study therapy mean 7 days after AMI. Median number of transplanted BMC was 324 × 10(6). CMR was performed prior to study therapy and annually up to 3 years and revealed no difference between BMC and placebo population. Patients treated with a cell number above the median experienced a significant improvement in LVEF compared with patients with cell number below the median 3.6 ± 3.4 versus -0.5 ± 6.4 % (difference 4.1, 95 % CI 0.2 to 8.1 %, p = 0.04) at 6 months. The difference in LVEF change between the groups remained with 3.8 % (p = 0.12) at 12 months, 4.5 % (p = 0.07) at 24 months and 5.6 % (p = 0.03) at 36 months. BMC treated patients without MO experienced a better improvement in LVEF compared with patients with MO at 6, 12, 24 and 36 months with 3.5, 5.3, 6.4 and 3.2 %., Conclusions: In the randomized, placebo-controlled double-blind SCAMI trial improvement in LVEF up to 3 years was higher in BMC patients treated with a high cell number or without MO.

Background: Within the coming decades, a steadily growing demand for blood products will face a shrinking blood donor population in many countries. After increasing the donor age of repeat donors for whole blood donation (WB) from 68 to 70 years in 2009 in our Blood Service, we investigated whether this is sufficient as a safe and effective strategy to sustain future blood supply., Materials and Methods: Between 1 March 2009 and 28 February 2011, WB donations from donors aged between 69 and 70 and their proportion of total donations in 2010 were determined. We analysed adverse reaction rates in donors with respect to sex and age and calculated mean annual donation frequencies., Results: Of all invited donors, 32·5% responded and contributed 0·98% (men) and 0·56% (women) to all WB units collected in 2010. The overall and systemic adverse reaction rate per 1·000 WB donations declined by age [men: 1·10 (95%CI: 0·84-1·35) vs. 0 (0-0·8), P < 0·0001; 0·99 (0·75-1·23) vs. 0 (0-0·8), P < 0·0001 and women: 1·80 (1·46-2·14) vs. 1·12 (0·1-2·66), P < 0·0001; 1·47 (1·17-1·78) vs. 1·12 (-0·43-2·66), P = 0·0004]. Mean donation frequencies were strongly correlated with increasing age (men: r = 0·953, P < 0·0001; women: r = 0·913, P < 0·0001) with peak values for 70-year-old male: 2·53 ± 1·37 vs. 1·79 ± 1·05, P < 0·0001 and female donors: 2·15 ± 1·06 vs. 1·52 ± 0·78, P < 0·0001., Conclusions: Elderly donors have very low adverse reaction frequencies and are highly committed to donate blood. Thus, we consider donations from repeat donors aged 69-70 safe and suggest it a powerful short- to midterm strategy to, at least partially, overcome the challenges of the demographic change., (© 2011 The Author(s). Vox Sanguinis © 2011 International Society of Blood Transfusion.)

BACKGROUND: The implementation of a new national German blood donor questionnaire was proposed to improve donor and recipient safety. METHODS: We compared deferral/exclusion rates of whole blood donors before (May 2010, n = 64,735) and after (May 2011, n = 71,687) the implementation of a new blood donor questionnaire. Considering seasonal variations, analysis was performed with respect to collection site (mobile vs. fixed), sex, donor status (first-time vs. repeat), age, and the frequencies of sexual risk behavior and other reasons for deferral. RESULTS: We observed a statistically significant increase (p < 0.001) of the overall deferral/exclusion rate from 6.2 to 8.1%, irrespective of type of collection site (fixed: from 6.0 to 8.5%; mobile: from 6.2 to 8.0%), sex (females: from 7.5 to 9.9%; males: from 5.1 to 6.6%), donor status (first-time donors: from 19.7 to 24.7%; repeat donors: from 4.6 to 6.3%) or age (18-29 years: from 9.1 to 11.7%; 60-71 years: from 5.1 to 6.6%). Confidential self-exclusion increased from 0.08 to 0.14% (p < 0.001). Besides risk behavior, various medical reasons could be identified that explain this increase. CONCLUSIONS: The new blood donor questionnaire resulted in an increased deferral/exclusion of all donor groups. Thus the impact on future blood supply must be considered carefully, and long-term studies and investigation of donor acceptance will be needed.

Congenital dyserythropoietic anaemias (CDAs) are heterogeneous, hereditary disorders hallmarked by ineffective erythropoiesis and tissue iron overload. Growth differentiation factor 15 (GDF15) was suggested to mediate iron overload in iron-loading anaemias, such as the thalassaemias and CDAI by suppressing hepcidin, the key regulator of iron absorption. Here, we show that serum GDF15 concentrations are elevated in subjects with CDAI and CDAII. Despite similar disease characteristics, CDAI patients present with significantly higher GDF15 concentrations compared to CDAII patients. Hepcidin concentrations are inappropriately low in CDAII patients considering the severe hepatic iron overload associated with this disorder. GDF15 significantly correlates with the degree of anaemia (Hb), the response of erythropoiesis (reticulocyte index) as well as with iron availability in the serum (transferrin saturation). The observation that GDF15 is elevated in CDAII patients is consistent with the proposal that GDF15 is among the erythroid factors down-regulating hepcidin and contributing to iron overload in conditions of dyserythropoiesis.

Background: Cryopreserved hematopoietic progenitor cells collected by apheresis from granulocyte-colony-stimulating factor with or without chemotherapy-mobilized patients have become the preferred type of autograft to support treatment of diseases amenable to high-dose chemotherapy. A novel apheresis system, the Spectra Optia v.5.0 (CaridianBCT), was constructed to meet certain shortcomings of manual apheresis systems such as the COBE Spectra MNC (CaridianBCT), including the need for continuous optical or manual monitoring and readjustment of buffy coat position and sensitivity to inconsistent blood flow. By use of optical sensors, which provide real-time automatic interface (buffy coat) and collection line control, the Spectra Optia promises to automatically guide apheresis procedures, potentially freeing up operator time and reducing variability in collection efficiency (CE2)., Study Design and Methods: In a two-center clinical trial, 35 autologous stem cell donors were subjected to apheresis with the Spectra Optia to validate feasibility and effectiveness of apheresis procedures. Results were compared to data from 80 autologous apheresis procedures with the COBE Spectra MNC., Results: Usability and function of the automatic interface management were excellent. CD34+ cell quality, assessed by viability staining, colony-forming unit-culture frequency, and engraftment kinetics, was equally good with both systems. CE2 of the Spectra Optia, calculated as CD34+ contents in the product divided by the number of CD34+ cells presented to the collection port, exceeded that of the COBE Spectra MNC. Spectra Optia product volumes were significantly smaller. Very high white blood cell and platelet counts modestly reduced CE2 with the Spectra Optia., Conclusion: The Spectra Optia is a novel automatic apheresis system supporting autologous stem cell collection with at least equal efficiency and superior user-friendliness compared to the COBE Spectra MNC., (© 2010 American Association of Blood Banks.)

Background: Cytomegalovirus (CMV) disease constitutes a serious complication after allogeneic stem cell transplantation. For the clearance of CMV, CD8+ T cells are pivotal., Study Design and Methods: Here, the novel streptamer technology was used at good manufacturing practice (GMP) level for adoptive transfer of CMV-specific T cells into acute leukemia patients with recurrent high CMV antigenemia after allogeneic stem cell transplantation., Results: After a single transfusion, the frequency of CMV-specific CD8+CD45RA+CCR7- effector T cells increased dramatically from 0.0% to a maximum of 27.1% of all T cells. These T cells were clearly donor derived and did not stem from intrinsic reconstitution, as demonstrated by analysis of 1) donor chimerism through single-tandem repeats, 2) T-cell receptor excision circles, and 3) Vβ-chain typing by polymerase chain reaction. Clinically, the specific T-cell transfer resulted in a persistent clearance of the CMV antigenemia, which allowed the patients to discontinue toxic antiviral drug therapy without further high-level reactivation of CMV, demonstrating the power of the streptamer technology., Conclusion: Taken together, the streptamer technology offers the advantage of selecting virus-specific CD8+ T cells at GMP level for adoptive T-cell transfer, thus inducing long-lasting specific CD8+ T-cell responses without increasing the risk for graft-versus-host disease., (© 2010 American Association of Blood Banks.)

Polyomavirus BK (BKV) is known as an important etiologic agent in the development of hemorrhagic cystitis (HC) after allogeneic stem cell transplant (SCT). To define T cell epitopes of the BKV proteins VP1 and sT, eight potential HLA-A2-binding peptides were synthesized based on computer algorithms. These peptides were co-incubated with CD8 + T cells from the peripheral blood (PB) of 25 healthy volunteers and seven patients suffering from HC after allogeneic SCT in a mixed-lymphocyte peptide culture (MLPC), which were subsequently screened by enzyme-linked immunospot (ELISPOT) assays and fluorescence-activated cell sorting (FACS) analysis. We found that CD8 + T cells from five of seven (71%) patients with HC presensitized with the BKV peptide VP1 p108 (LLMWEAVTV) specifically recognized T2 cells pulsed with VP1 p108. In contrast, only seven of 25 (28%) healthy volunteers had CD8 + T cells reactive with VP1 p108-pulsed T2 cells. The presence of VP1 p108-specific T cells could be confirmed by FACS analysis. The BKV peptide VP1 p108 seems to play an important role as an immunodominant peptide in the pathogenesis of HC in patients after allogeneic SCT, and might be a promising target for immunotherapies or even strategies to prevent the development of BKV-associated HC.

To assess the effect of autologous bone-marrow cell (BMC) therapy in patients with acute myocardial infarction in a rigorous double-blind, randomized, placebo-controlled trial. Patients with reperfusion >6 hours after symptom onset were randomly assigned in a 2:1 ratio to receive intracoronary BMC or placebo therapy 5 to 7 days after symptom onset. The patients were stratified according to age, acute myocardial infarction localization, and left ventricular (LV) function. Rigorous double-blinding was ensured using autologous erythrocytes for the placebo preparation that was visually indistinguishable from the active treatment. Serial cardiac magnetic resonance imaging studies were performed before study therapy and after 1, 3, and 6 months. The primary end point was the difference in the LV ejection fraction from baseline to 6 months. The secondary end points included changes in the LV end-diastolic and end-systolic volume indexes and infarct size. A total of 42 patients were enrolled (29 in the BMC group and 13 in the placebo group) in the integrated pilot phase. A mean of 381 x 10(6) mononuclear BMCs were administered. The baseline clinical and cardiac magnetic resonance imaging parameters did not differ. Compared to baseline, the difference in LV ejection fraction for the placebo group versus BMC group was 1.7 +/- 6.4% versus -0.9 +/- 5.5% at 1 month, 3.1 +/- 6.0% versus 1.9 +/- 4.3% at 3 months, and 5.7 +/- 8.4% versus 1.8 +/- 5.3% at 6 months (primary end point; not significant). No difference was found in the secondary end points between the 2 groups, including changes in infarct size or LV end-diastolic and end-systolic volume indexes. In conclusion, in this rigorous double-blind, randomized, placebo-controlled trial, we did not observe an evidence for a positive effect for intracoronary BMC versus placebo therapy with respect to LV ejection fraction, LV volume indexes, or infarct size., (Copyright 2010 Elsevier Inc. All rights reserved.)

Peptide vaccination constitutes a novel immunotherapeutical approach for the treatment of patients with solid tumors, lymphoma and leukemia. Moreover it might be of use in hematooncological patients for the prevention and therapy of infections like cytomegalovirus (CMV) reactivation due to immunosuppression. To meet good manufacturing practice (GMP) criteria, we introduce here a bio-assay to validate peptide vaccines for peptide content and bio-activity. As a paradigm for peptide vaccine preparation the immunogenic CMV peptide 495-503 NLVPMVATV lyophilisate was resolubilized in dimethyl sulfoxide, phosphate buffered saline and admixed with Montanide. Addition of different amounts of peptide (10-80 microg) to a mixed lymphocyte peptide culture (MLPC) resulted in the generation of interferon (IFN) gamma and granzyme B releasing CD8(+) CMV tetramer(+) T cells in a dose dependent manner. The combination of FACS and ELISPOT results allowed the definition of the peptide amount in a vaccine preparation. Storage at +/-4 degrees C over 24 h did not result in a significant change of the immunogenicity of the vaccine. In contrast, cryopreservation of the vaccine at -20 degrees C resulted in a loss of immunogenicity. Quantitation of tumor/viral antigen peptides admixed with adjuvants, such as incomplete Freund's adjuvant (IFA), is feasible through bio-assays as the modified ELISPOT/FACS assay described here, meeting GMP criteria for multi-center trials.

Background: Cytomegalovirus (CMV) disease represents a serious complication after allogeneic peripheral blood stem cell (PBSC) transplantation. If possible, stem cell donors for transplantation are selected on the basis of their CMV serostatus. However, the cytomegalovirus-specific immune status can be further characterized by measuring CMV phosphoprotein 65-specific CD8(+) T cell frequencies using tetramers, pentamers, and streptamers. We therefore investigated the specificity and sensitivity of all 3 methods and compared the results to patient serostatus., Methods: Twenty-three samples from CMV-seropositive healthy volunteers and 15 samples from CMV-seropositive patients before and after allogeneic PBSC transplantation were stained with tetramers, pentamers, or streptamers and analyzed by flow cytometry., Results: Similar frequencies of CD8(+) and multimer(+) T cells could be measured by all 3 multimer technologies. The lowest background signals (< or =0.02%) were obtained using tetramer technology. Frequencies of 0.19%-2.48% of CMV phosphoprotein 65 495-503-specific CD8(+) T cells were detected in healthy volunteers. Antigen-specific T cells were detected in only 11 (48%) of 23 seropositive healthy volunteers. CMV antigenemia before day 100 after allogeneic PBSC transplantation occurred in 2 of 3 patients without any specific T cells., Conclusion: These findings demonstrate the power of multimer staining and a certain limitation of serologic testing to define appropriate donors for transplantation. Therefore, whenever possible, CMV-seropositive donors of transplants to seropositive recipients should be screened for their CD8(+) T cell frequency. All 3 multimer technologies can be used, yielding similar results. The streptamer technology additionally offers the advantage of selecting CMV phosphoprotein 65-specific CD8(+) T cells at the good manufacturing practice level for adoptive T cell transfer.

Background: Dendritic cells (DCs) generated from leukemic blasts constitute a promising tool in immunotherapy for acute myeloid leukemia patients (AML-DCs), because AML-DCs express human leukocyte antigens and costimulatory molecules such as CD40, CD80, and CD86 at a higher level than leukemic blasts. Potentiation of AML-DC vaccine might become feasible by the addition of adjuvants such as lipopolysaccharides (LPS) or CPG-rich oligodeoxyribonucleotides binding to Toll-like receptors (TLR) and inducing a stronger Type 1 T-cell response., Study Design and Methods: mRNA and protein expression of TLR-2, -4, and -9 were analyzed with quantitative real-time polymerase chain reaction, Western blot, and flow cytometry for mature monocyte-derived DCs generated from 14 AML patients versus 14 healthy volunteers (HV-DCs), and the response of the AML- and HV-DCs to different microbial TLR ligands was determined by enzyme-linked immunosorbent assay for the proinflammatory cytokines tumor necrosis factor (TNF)-alpha, inducible protein (Ip)-10, and interleukin (IL)-6., Results: AML-DCs and HV-DCs strongly expressed TLR-2 and TLR-4, while TLR-9 was expressed at a lower level in both groups. There was no significant difference in TLR expression between the two groups of AML-DCs and HV-DCs. In accordance with the TLR expression levels, DCs generated from both AML patients and HVs responded to the known microbial ligands peptidoglycan (PGN) and lipoteichoic acid for TLR-2 and LPS as ligand for TLR-4, by producing TNF-alpha and IL-6. A response to the ODNs 2006 and 2216 binding to TLR-9 was only detected in AML-DCs., Conclusion: Microbial ligands like ODNs and LPS constitute promising adjuvants for enhancing (AML-) DC vaccines.

Cell labeling by superparamagnetic iron oxide particles (SPIO) has emerged as a potentially powerful tool to monitor trafficking of transplanted cells by magnetic resonance tomography, e.g., in studies for tissue repair. However, intracellular labeling is mostly achieved by transfection agents not approved for clinical use. In this work, the feasibility and efficiency of labeling human mesenchymal stem cells (MSC) and HeLa cells with two commercially available SPIOs (Resovist and Feridex) without transfection agents was evaluated. In both cell types, Resovist without a transfection agent was more efficiently taken up than Feridex. Increasing the concentration of Resovist can yield similar amounts of iron in cells as SPIOs with transfection agents. This offers the opportunity to omit transfection agents from the labeling protocol when Resovist is used. Intracellular localization of the contrast agents is found by light microscopy and confirmed by electron microscopy. Coagulation of the SPIO nanoparticles, which is problematic for the quantification of the intracellular iron content, was observed and analyzed with a fluorescent activated cell sorter. As Resovist consists of a carboxydextran shell in contrast to Feridex which is composed of a dextran shell, we synthesized fluorescent polymeric nanoparticles as model systems with different amounts of carboxyl groups on the surface by the miniemulsion process. A steady increase in uptake of nanoparticles was detected with a higher density of carboxyl groups showing the relevance of charged groups as in the case of Resovist. Aggregation of these polymeric nanoparticles was not found.

We present a case report of a successful high-dose melphalan therapy and autologous stem cell transplantation without the use of allogeneic blood product support in a 70-year-old patient suffering from multiple myeloma. Based on the experience in this case and thorough evaluation of the literature, we consider pre-transplant Hb level of 11-12 g/dl, platelet count higher than 70/nl, good WHO performance status of two and lower and informed consent as important eligibility criteria. During cytopenia recommended supportive measures include growth factor support with erythropoietin and G-CSF, p.o. iron treatment as well as prophylactic use of anti-fibrinloytic agents. Furthermore we discuss additional options that might be considered depending on the individual factors as e.g. pre-transplant collection and cryoconservation of autologous platelet concentrates. Moreover, an analysis of socio-economic issues regarding this procedure is presented. We conclude that allogeneic blood product free transplantation is a feasible procedure that can be offered to the patients belonging to distinct religious groups refusing allogeneic blood products as Jehovás Witnesses and patients presenting other contraindications for transfusions.

Background: Catumaxomab is an antibody that binds with one arm epithelial cell adhesion molecule (EpCAM) positive tumors and with the other arm CD3+ T cells. Intravenous application of therapeutic antibodies may result in intravascular cytokine release., Aim: In this pilot trial we assessed whether cytokine release can be controlled by ex vivo cell opsonization and cytokine wash-out before administration of catumaxomab, preserving its anti-cancer activity. In addition, preliminary data on safety of and clinical response to catumaxomab coated autologous immune cells were acquired., Methods: Peripheral blood mononuclear cells (PBMNC) of four patients with recurrent head and neck carcinoma were collected by leukapheresis, incubated ex vivo with catumaxomab for 24 h and cleared from released cytokines. Each patient received an escalated number of antibody-coated PBMNC equivalent to 1 x 10(4), 1 x 10(5), 1 x 10(6) and 1 x 10(7) CD3(+) cells/kgBW intravenously at bi-weekly intervals., Results: After opsonization, PBMNC released substantial amounts of interferon gamma (IFNgamma) and tumor necrosis factor alpha (TNFalpha) in vitro, which were removed before administration. Catumaxomab up-regulated CD25, CD69, and CD83 on PBMNC, and catumaxomab loaded PBMNC released IFNgamma and granzyme B when coincubated with EpCAM(+) BHY cells, suggesting cell activation and target directed biological activity. During the study period, one patient died of aspiration pneumonia and one patient needed a tracheotomy. Treatment related adverse events (AE) occurred at the highest cell dose in two patients, whereas 1 x 10(6) loaded CD3(+) cells/kgBW were well tolerated by all patients. One patient showed stable disease for 6 months and one patient is in complete remission for 27 months., Conclusion: Ex vivo opsonization of PBMNC with catumaxomab provided biologically active, tumor targeting cells. Extracorporeal PBMNC coating may be an option to control intravascular cytokine release induced by therapeutic antibodies.

Background: Mononuclear cells (MNCs) of severely impaired acute myeloid leukemia (AML) patients may be collected by leukapheresis for large-scale generation of dendritic cells (AML-DCs) under good manufacturing practice (GMP) conditions for adoptive immunotherapy., Study Design and Methods: In five end-stage AML patients, a leukapheresis procedure was performed with a cell separator (either COBE Spectra [Gambro BCT] or Amicus [Baxter]). For large-scale AML-DC generation, the MNCs of a single leukapheresis concentrate were isolated by density gradient and plated into a cell factory under GMP conditions. The AML-DCs were harvested on Day 8 of culture, and their viability, the mature morphology, and the phenotype were evaluated. The AML-DCs were injected subcutaneously into five AML patients up to four times at a biweekly interval., Results: All AML patients entered the leukapheresis procedure with a highly pathologic blood count. In a mean separation time of 198 +/- 33 minutes, a mean of 1.3 +/- 0.2-fold the total blood volume was processed with a white blood cell (WBC) yield of 9 x 10(9) to 70 x 10(9) per collection dependent on the precollection WBC count. After density gradient a mean of 2.2 x 10(9) +/- 0.3 x 10(9) MNCs were plated into a cell factory. This resulted in a mean viable and mature DC yield of 0.01 x 10(9) of MNCs., Conclusion: The leukapheresis procedure is a feasible and safe procedure even in patients with hematologic malignancies and highly pathologic blood counts. Sufficient amounts of MNCs can be collected in leukopenic patients and the large-scale generation of AML-DCs in cell factories under GMP conditions yields in an adequate quantity of viable and mature AML-DCs.

Gene transfer into human CD34+ haematopoietic progenitor cells (HPC) and multi-potent mesenchymal stromal cells (MSC) is an essential tool for numerous in vitro and in vivo applications including therapeutic strategies, such as tissue engineering and gene therapy. Virus based methods may be efficient, but bear risks like tumorigenesis and activation of immune responses. A safer alternative is non-viral gene transfer, which is considered to be less efficient and accomplished with high cell toxicity. The truncated low affinity nerve growth factor receptor (ALNGFR) is a marker gene approved for human in vivo application. Human CD34+ HPC and human MSC were transfected with in vitro-transcribed mRNA for DeltaLNGFR using the method of nucleofection. Transfection efficiency and cell viability were compared to plasmid-based nucleofection. Protein expression was assessed using flow cytometry over a time period of 10 days. Nucleofection of CD34+ HPC and MSC with mRNA resulted in significantly higher transfection efficiencies compared to plasmid transfection. Cell differentiation assays were performed after selecting DeltaLNGFR positive cells using a fluorescent activating cell sorter. Neither cell differentiation of MSC into chondrocytes, adipocytes and osteoblasts, nor differentiation of HPC into burst forming unit erythroid (BFU-E) colony forming unit-granulocyte, erythrocyte, macrophage and megakaryocyte (CFU-GEMM), and CFU-granulocyte-macrophage (GM) was reduced. mRNA based nucleofection is a powerful, highly efficient and non-toxic approach for transient labelling of human progenitor cells or, via transfection of selective proteins, for transient manipulation of stem cell function. It may be useful to transiently manipulate stem cell characteristics and thus combine principles of gene therapy and tissue engineering.

A pilot trial was initiated for chronic myeloid leukaemia patients, which employed imatinib for remission induction, followed by reduced-intensity conditioning and an in vivo T-cell depleted graft. Out of nine patients, six experienced a molecular relapse and one patient had a haematological relapse at a median interval of 5 months after transplantation. Five relapsing patients achieved a 2nd molecular remission after treatment with either donor lymphocyte infusions (n = 4) or imatinib (n = 1). Two of nine patients died due to infectious complications. The probability of survival 2 years after transplant was 74% (95% CI 42-100%).

Specific immunotherapies for patients with chronic myeloid leukemia (CML) might eliminate residual CML cells after therapy with imatinib or chemotherapy and might enhance a specific graft-versus-leukemia effect after allogeneic stem cell transplantation. Here, we investigated the mRNA expression and T-cell recognition of tumor-associated antigens or leukemia-associated antigens (LAAs) in 34 patients with CML. Several LAAs are expressed in CML and therefore are candidate structures for specific immunotherapies: bcr-abl (100%), G250 (24%), hTERT (53%), MPP11 (91%), NEWREN60 (94%), PRAME (62%), Proteinase3 (71%), RHAMM/CD168 (83%), and WT1 (53%), but not BAGE, MAGE-A1, SSX2, or NY-ESO-1. The frequency of mRNA expression of RHAMM/CD168, Proteinase3, and PRAME was higher in acceleration phase and blast crisis. In flow cytometry, CD34+ progenitor cells typed positive for HLA molecules but were deficient for CD40, CD80, CD83, and CD86. However, RHAMM/CD168 R3-peptide (ILSLELMKL)-specific T-cell responses in CML patients were demonstrated by ELISPOT analysis and specific lysis of RHAMM/CD168 R3-pulsed T2 cells and CD34+ CML cells in chromium-51 release assays. RHAMM-R3-specific T cells could be phenotyped as CD8+R3*tetramer+CD45RA+CCR7-CD27- early effector T cells by tetramer staining. Therefore, vaccination strategies inducing such RHAMM-R3-directed effector T cells might be a promising approach to enhance specific immune responses against CML cells.

Vaccination with dendritic cells (DCs) as professional antigen presenting cells generated from autologous leukemic blasts might elicit anti-leukemic T cell responses in patients with acute myeloid leukemia (AML). To test this hypothesis, autologous AML-DC were generated under good manufacturing practice (GMP) conditions and injected s.c. into five AML patients up to four times at a biweekly interval. No severe adverse side effects were observed. Three patients remained in a stable condition for 5.5-13 months and two patients died from rapidly progressive AML. Compared to the initial T cell frequency, enzyme linked immunosorbent spot (ELISPOT) assays revealed a significant increase of granzyme B releasing CD8+ T cells specifically recognizing the PRAME derived peptide (ALYVDSLFFL), a leukemia associated antigen expressed by AML blasts. The cytokine levels in the serum of vaccination AML patients as assessed by cytokine bead assay changed over the period of vaccination to an elevated type 1 T helper cell pattern. Interferon gamma production by CD4+ T helper cells increased during vaccination. In summary, we demonstrated that autologous AML-DC vaccination is well tolerated and can result in an enhanced and specific response of cytotoxic T cells in AML patients.

Genetic labeling of human hematopoietic progenitor cells (HPC) and their consecutive fate-mapping in vivo is an approach to answer intriguing questions in stem cell biology. We recently reported efficient transient genetic labeling of human CD34+ HPC with the truncated low-affinity nerve growth factor receptor (DeltaLNGFR) for in vivo application. Here we investigate whether HPC labeling with DeltaLNGFR affects lineage-specific cell differentiation, whether DeltaLNGFR expression is maintained during lineage-specific cell differentiation and which leukemia cell line might be an appropriate cell culture model for human CD34+ HPC. Human CD34+ peripheral blood stem cells and various leukemia cell lines were characterized by immunophenotyping. Cells were transfected using nucleofection. Hematopoietic differentiation was studied by colony-forming assays. DeltaLNGFR expression was assessed using reverse transcription-PCR, immunofluorescence and flow cytometry. Nucleofection was efficient and did not significantly reduce hematopoietic cell differentiation. Mature myeloid cells (CD66b+) derived from human CD34+ HPC and Mutz2 cells maintained DeltaLNGFR expression at a high percentage (70 +/- 2% and 58 +/- 2%, respectively). Mutz2 cells may serve as an in vitro model for human myeloid HPC. The method described herein has been adopted to Good Manufacturing Practices (GMP) guidelines and is ready for in vivo application.

Unlabelled: Intensification of the conditioning regimen with a radioactively labeled anti-CD66 antibody is feasible before allogeneic stem cell transplantation. The use of radioimmunotherapy may deliver a significant dose of radiation to the kidneys. We therefore studied the incidence and clinical picture of bone marrow transplantation (BMT) nephropathy in our patients receiving radioimmunotherapy before allogeneic stem cell transplantation., Methods: This study was a clinical trial of 114 consecutive patients who received conditioning with a radiolabeled anti-CD66 antibody-188Re (n = 93) or 90Y (n = 21)-between 1998 and 2003., Results: Although BMT nephropathy has developed in none of the patients in the [90Y]anti-CD66 group, 6 of 93 patients receiving [188Re]anti-CD66 presented with signs of BMT nephropathy at a median of 11.5 mo after stem cell transplantation. The absorbed renal dose was significantly lower in the 90Y group (4 vs. 7 Gy, P < 0.0001). Of the patients receiving [188Re]anti-CD66 who are alive, BMT nephropathy developed in 19% (6/32). Five of 6 patients with BMT nephropathy received total-body irradiation. The patients presented with elevated serum creatinine, proteinuria, anemia, hypertension, and signs of microangiopathy. All 6 patients in whom BMT nephropathy has developed are alive at a median follow-up of 58 mo after stem cell transplantation, and 1 patient has entered a dialysis program., Conclusion: BMT nephropathy appears to be a significant problem after allogeneic stem cell transplantation with intensified conditioning using the 188Re-labeled anti-CD66 applied in this study, particularly when combined with total-body irradiation.

In a phase I-II study for patients aged 55-65 years, we employed radioimmunotherapy using an anti-CD-66 antibody as part of a dose-reduced conditioning regimen, which was followed by a T-cell-depleted graft. 20 patients with a median age of 63 years suffering from acute leukaemia (n=17) or myelodysplastic syndrome (n=3) received the antibody labelled either with 188Rhenium (n=8) or with 90Yttrium (n=12) during conditioning. Radioimmunotherapy provided a mean dose of 21.9 (+/-8.4) Gy to the bone marrow with a significantly higher dose when 90Yttrium was used. Additional conditioning was fludarabine-based plus anti-thymocyte globulin in matched related donor transplants (n=11), or plus melphalan in matched unrelated donor transplants (n=9). Regimen-related toxicity was low, with two patients developing three episodes of grade III organ toxicity. All patients engrafted, grade II-IV acute graft-versus-host disease (GvHD) was observed in one patient (5%) and chronic GvHD in three patients (15%). The cumulative incidence of non-relapse mortality was 25%, the cumulative incidence of relapse 55%. The probability of survival was estimated to be 70% at 1 year and 52% at 2 years post-transplant, although no plateau was reached afterwards. In conclusion, radioimmunotherapy using the anti-CD66 antibody was feasible and safe in our elderly patient group and provided a high marrow dose.

The receptor for hyaluronic acid-mediated motility (RHAMM/CD168) has been described as a leukemia-associated antigen. To define T-cell epitopes of RHAMM/CD168 toward specific immunotherapies for acute myeloid leukemia (AML), 10 potential HLA-A2-binding RHAMM/CD168 peptides (R1 to R10) were synthesized based on computer algorithms and screened by enzyme-linked immunospot (ELISPOT) analysis using CD8+ T cells isolated from peripheral blood (PB) of patients with AML and healthy donors. We found that CD8+ cells from 7 of 13 (54%) patients with AML presensitized with peptides R3 (ILSLELMKL) or R5 (SLEENIVIL) specifically recognized T2 cells pulsed with R3 (39%) or R5 (15%) peptide. In contrast, only 4 of 21 (19%) healthy volunteers had CD8+ cells reactive with R3- or R5-pulsed T2 cells after presensitization. The presence of R3 peptide-specific effector T cells in the peripheral blood of patients with AML could be confirmed by staining as HLA-A2/R3 peptide tetramer+ CCR7-CD45RA+ cells. In chromium-51 release assays, peptide-primed CD8+ T cells from patients with AML were able to lyse RHAMM/CD168 peptide-pulsed T2 cells, AML blasts, and dendritic cells generated thereof (AML DCs). Transfection of COS7 cells with RHAMM/CD168 cDNA revealed that peptides R3 and R5 are naturally processed epitopes of RHAMM/CD168 that are presented in an HLA-A2-restricted manner. In summary, RHAMM/CD168 is a promising target for immunotherapies in patients with AML, and we have therefore initiated a clinical vaccination trial with R3 peptide. Because RHAMM/CD168 is also expressed in various other hematologic malignancies and solid tumors, vaccines targeting this antigen may have even wider application.

Recently, the focus is on new specific immunotherapies for AML such as cellular therapies employing dendritic cells (DCs) generated from AML blasts. AML-DCs express constitutionally leukemia-associated antigens (LAAs) present in AML blasts they are generated from. Here we investigated whether the generation of AML-DCs would alter the expression level of LAAs. Moreover, we evaluated the presence of HLA and costimulatory molecules on AML blasts versus AML-DCs. Quantitative real-time polymerase chain reaction (PCR) was performed for the following LAAs: preferentially expressed antigen in melanoma (PRAME), the receptor for hyaluronic acid mediated motility (RHAMM/CD168), Wilms' tumor gene 1 (WT-1) and proteinase 3. The expression of HLA-ABC, HLA-DR, CD40, CD80, CD83 and CD86 was evaluated by flow cytometry. RHAMM protein expression was evaluated by immunocytochemistry, recognition of AML-DCs by PRAME epitope-specific T cells was evaluated in a chromium-release assay. Quantitative real-time PCR for AML-DCs versus AML blasts showed an alteration in mRNA expression of LAAs. An elevated PCR signal for PRAME was detected in 7/12 AML-DC preparations. 6/12 AML-DC preparations showed a significant upregulation of the PCR signal for RHAMM. A stronger WT-1 and proteinase-3 signal was observed in PCR for only 2/12 and 1/12 AML-DCs , respectively. All preparations showed a strong expression of at least one of the LAAs examined. As demonstrated by flow cytometry, AML-DCs strongly upregulated costimulatory molecules like CD40 and CD80 in comparison with AML blasts. AML-DCs tested positive for RHAMM protein. PRAME positive AML-DCs were recognized by specific T cells. AML-DCs might constitute a powerful tool in immunotherapy for AML. Real-time PCR allows a quick and quantitative assessment of immunologically relevant LAA expression with only 10(5) DCs and might be helpful for the decision whether the AML-DC vaccination strategy is favourable or not.

Tissue regeneration with human hematopoietic or mesenchymal stem cells has become a fashionable research topic. In cardiology, intracoronary injection of adult stem cells has already been used for the treatment of human myocardial infarction and ischemic cardiomyopathy. The experimental background of such therapies, however, i.e. the potential of adult stem cells to regenerate myocardium through "transdifferentiation" of hematopoietic or mesenchymal stem cells into cardiomyocytes described in animal models, has recently been challenged by other experimental data. Nonetheless, clinical trials are continuing. This may be due to the fact that, in open-labeled pilot trials, a benefit of intracoronary injection of adult stem cells for the treatment of myocardial infarction has been described. As pilot trials may overemphasize the beneficial effects of intracoronary injection of bone marrow stem cells, controlled double-blinded randomised multicenter studies are warranted. Furthermore, a careful characterization of the cells involved in the proposed cardiac repair as well as in vivo-monitoring of such cells following intracoronary injection in humans might help to answer many essential questions linked to this important research topic. The latter requires biocompatible labeling. This review focuses on the technologies available for stem cell labeling and summarizes the arguments and contra-arguments to use these labeling technologies for application in humans.

Background: The trifunctional bispecific antibody Removab (tbAB) bridges and activates CD3 positive T cells to EpCAM on carcinoma cells and simultaneously binds to an accessory immune-cell inducing tumor cell lysis. tbAB-induced tumor cytotoxicity was assessed in an autologous human ex vivo system., Methods: One hundred forty tumor samples and autologous peripheral blood mononuclear cells from a total of 36 patients with head and neck squamous cell carcinomas (HNSCCs) were incubated on a chicken embryo chorioallantois membrane with Removab. Tumor cells coincubated with cisplatin or cell culture medium served as positive and negative controls. Tumor cell lysis was assessed by acridine orange staining or by fluorescence-activated cell sorting of propidium iodide-marked cells after 24 and 48 hours (T24/T48) coincubation., Results: Coincubation of HNSCC cells with tbAB and autologous peripheral blood mononuclear cells resulted in a 49% +/- 6% decrease of viable cells at T24 (p < .005) and in a decrease of 56% +/- 8% at T48 (p < .005) compared with the control. The tumor cytotoxicity was similar to that of cisplatin (49% +/- 7% decrease at T24 and 49% +/- 8% at T48)., Conclusion: In an autologous human ex vivo system, the tbAB-induced tumor cell lysis was comparable to that by cisplatin., (2005 Wiley Periodicals, Inc.)

Regulation of sensitivity or resistance for apoptosis by death receptor ligand systems is a key control mechanism in the hematopoietic system. Dysfunctional or deregulated apoptosis can potentially contribute to the development of immune deficiencies, autoimmune diseases, and leukemia. Control of homeostasis starts at the level of hematopoietic stem cells (HSC). To this end, we found that CD34+ hematopoietic progenitor cells are constitutively resistant to CD95-mediated apoptosis and cannot be sensitized during short-term culture to death receptor-mediated apoptosis by cytokines. Detailed analysis of the death machinery revealed that CD34+ cells do not express caspase-8a/b, a crucial constituent of the death-inducing signaling complex (DISC) of death receptors. Instead, we found a smaller splice variant termed caspase-8L to be present in HSC. Forced expression of caspase-8L using a recombinant lentiviral vector was able to protect hematopoietic cells from death receptor-induced apoptosis even in the presence of caspase-8a/b. Furthermore, we found that caspase-8L is recruited to the DISC after CD95 triggering, thereby preventing CD95 from connecting to the caspase cascade. These results demonstrate an antiapoptotic function of caspase-8L and suggest a critical role as apoptosis regulator in HSC. Similar to CD34+ HSC, stem cell-derived leukemic blasts from AML(M0) patients only expressed caspase-8L. Additionally we found, caspase-8L expression in several AML and ALL samples. Thus, caspase-8L expression might explain constitutive resistance to CD95-mediated apoptosis in CD34+ progenitor cells and might participate in the development of stem cell-derived and other leukemias by providing protection from regulatory apoptosis.

Removab is a trifunctional bispecific antibody which can bridge CD3+ T cells and epithelial cell adhesion molecule positive (EpCAM+) tumor cells, and binds with its Fc fragment to antigen presenting cells. To explore a new approach for the treatment of patients with carcinoma of the upper aerodigestive tract, we investigated whether Removab can induce specific cellular responses to the EpCAM+ carcinoma cell line BHY. Particular emphasis was put on the opsonization of peripheral blood mononuclear cells (PBMN) with respect to clinical application. Tumor cells and allogeneic PBMN of healthy volunteers were incubated with or without Removab. In a third group, PBMN were opsonized with Removab and washed before incubation with tumor cells. Inverse microscopy, ELISPOT, flow cytometry analysis and cytotoxicity assays on the chorioallantois membrane (CAM) were performed. In comparison with PBMN alone, opsonization with Removab resulted in: a) activation of CD83+ antigen presenting cells, b) secretion of interferon gamma, and c) granzyme B mediated lysis of targeted BHY cells by EpCAM specific CD8+ T cells. The secretion of tumor necrosis factor alpha, interferon gamma and interleukin-2 by opsonized PBMN was significantly reduced after 24 h. Washed opsonized PBMN maintained their lytic activity against tumor cells as tested on the CAM. Removab is an appropriate agent for the therapeutic amplification of T cell responses against EpCAM+ tumor cells by opsonization of PBMN without putting patients at risk for severe adverse events caused by a cytokine storm.

The present study investigated the effects of CD34(+) cell selection in 102 patients using the CliniMACS device. Patients were at high risk for the development of graft versus host disease (GvHD) because of age, or the use of a haploidentical, mismatched or unrelated donor (UD). The median age of the patients was 44 years. The CliniMACS procedure yielded 8.0 x 10(6) CD34(+) cells/kg and the number of residual T cells was 1.3 x 10(4)/kg (median). The median follow up was 20.6 months. The probability of graft failure was 7%. The rate of acute GvHD was low (compatible family donors 10%, UDs 17%, and haploidentical donors 26%) with no patient enduring more than grade II disease. The cumulative incidence of chronic GvHD at the median follow up after transplant was 15% for the compatible family donor group, 40% for the UD group and 78% in the group transplanted from a haploidentical donor Treatment failure was mainly because of transplant-related mortality, especially aspergillus infection, and not due to relapse. The probability of disease-free survival, stratified for the risk of treatment failure, was 27% for the high risk, 46% for the intermediate risk and 83% for the low risk group.

Data of 507 granulocyte donations from 183 donors were evaluated. No severe granulocyte colony-stimulating factor (G-CSF)-related side-effects were observed. Three donors complained of severe itching following infusion of hydroxyethyl starch (HES). A high proportion (85%) of the donors stated that they would donate granulocytes again. The mean granulocyte yield was 4.3 x 10(10). High-molecular-weight HES resulted in a significantly higher yield compared with low-molecular-weight HES. Mild, but no severe, adverse transfusion reactions were observed in 16% of the recipients. A leucocyte alloimmunization rate of 24% was found. G-CSF stimulation and transfusion of G-CSF-mobilized granulocytes were well tolerated by donors and recipients, respectively.