Abstract Interactions of hematopoietic progenitor cells (HPC) with their local microenvironments in the bone marrow are thought to control homing, differentiation, and self-renewal of the cells. To ...dissect the role of extracellular matrix (ECM) components of the niche microenvironment, a set of well-defined ECM coatings including fibronectin, heparin, heparan sulphate, hyaluronic acid, tropocollagen I, and co-fibrils of collagen I with heparin or hyaluronic acid was prepared and analysed with respect to the attachment of human CD133+ HPC in vitro. The extension of the adhesion areas of individual cells as well as the fraction of adherent cells were assessed by reflection interference contrast microscopy (RICM). Intense cell–matrix interactions were found on surfaces coated with fibronectin, heparin, heparan sulphate, and on the collagen I based co-fibrils. Insignificant adhesion was found for tropocollagen I and hyaluronic acid. The strongest adhesion of HPC was observed on fibronectin with contact areas of about 7 μm2 . Interaction of HPC with coatings consisting of heparin, heparan sulphate, and co-fibrils result in small circular shaped contact zones of 3 μm2 pointing to another, less efficient, adhesion mechanism. Analysing the specificity of cell–matrix interaction by antibody blocking experiments suggests an integrin( α5 β1 )-specific adhesion on fibronectin, while adhesion on heparin was shown to be mediated by selectins (CD62L). Taken together, our data provide a basis for the design of advanced culture carriers supporting site-specific proliferation or differentiation of HPC.
A regimen of busulfan and cyclophosphamide is standard therapy before transplantation of allogeneic hematopoietic stem cells in patients with chronic myelogenous leukemia (CML) or myelodysplastic ...syndrome (MDS). The clinical trial reported here was undertaken to test the hypothesis that fludarabine can replace cyclophosphamide in this regimen and facilitate donor engraftment with reduced toxicity. The conditioning regimen consisted of 30 mg/m2 intravenous fludarabine daily from day -9 to day -6, and oral busulfan given at 1 mg/kg 4 times a day every 6 hours from day -5 to day -2, with doses adjusted to target plasma levels of 900 ± 100 ng/mL at steady state. Cyclosporine and methotrexate were used for prophylaxis for graft-versus-host disease. Enrolled were 42 patients with high-risk CML (n = 4) or MDS (n = 38). The median patient age was 52 years (range, 12-65 years). Mobilized blood stem cells were obtained from HLA-compatible siblings (n = 16) or unrelated donors (n = 26). Engraftment was achieved in all patients, and the day-100 regimen-related mortality was 7%. With a median follow-up of 18 months (range, 13-27 months), the probabilities of overall survival, disease-free survival, and nonrelapse mortality were 42.4%, 34.9%, and 24%, respectively. These data indicate that the combination of fludarabine and targeted busulfan is sufficiently immunosuppressive to facilitate engraftment of blood stem cells from HLA-matched siblings and unrelated donors. Based on these encouraging results, further studies of fludarabine and targeted busulfan are warranted in standard-risk patients.
Therapeutic application of natalizumab, an anti-CD49d Ab, in patients with multiple sclerosis (MS) has been associated with increased levels of circulating CD34+ progenitors. We analyzed the ...frequency, phenotype and functional activity of CD34+ HSC in blood and BM of patients with MS who were treated with natalizumab. Compared with healthy controls and untreated MS patients, natalizumab treatment increased CD34+ cells in the peripheral blood 7-fold and in BM 10-fold. CD34+ cells derived from blood and marrow of natalizumab-treated patients expressed less of the stem cell marker CD133, were enriched for erythroid progenitors (CFU-E) and expressed lower levels of adhesion molecules than G-CSF-mobilized CD34+ cells. The level of surface CXCR-4 expression on CD34+ cells from patients treated with natalizumab was higher compared with that of CD34+ cells mobilized by G-CSF (median 43.9 vs 15.1%). This was associated with a more than doubled migration capacity toward a chemokine stimulus. Furthermore, CD34+ cells mobilized by natalizumab contained more mRNA for p21 and less for matrix metallopeptidase 9 compared with G-CSF-mobilized hematopoietic stem cell (HSC). Our data indicate that G-CSF and CD49d blockade mobilize different HSC subsets and suggest that both strategies may be differentially applied in specific cell therapy approaches.
Bortezomib is a potent drug for the treatment of multiple myeloma. Its anti-tumor activity is mediated by proteasome inhibition leading to decreased cell proliferation and induction of apoptosis. ...However, an unimpaired proteasomal function plays a crucial role for the induction of anti-tumor immunity by dendritic cells (DCs), which are currently used for therapeutic vaccination against various tumors including myeloma. In the present study, we investigated the impact of bortezomib on the immunostimulatory capacity of 6-sulfo LacNAc (slan) DCs, which represent a major subset of human blood DCs. We demonstrated that this proteasome inhibitor efficiently impairs the spontaneous in vitro maturation of slanDCs and the release of tumor necrosis factor (TNF)-alpha as well as interleukin (IL)-12 upon lipopolysaccharide (LPS) stimulation. Functional data revealed that bortezomib profoundly inhibits slanDC-induced proliferation and differentiation of CD4(+) T cells. In addition, the capacity of slanDCs to promote interferon-gamma secretion and tumor-directed cytotoxicity of natural killer (NK) cells is markedly impaired by bortezomib. These results provide evidence that bortezomib significantly reduces the ability of native human blood DCs to regulate innate and adaptive anti-tumor immunity and may have implications for the design of therapeutic strategies combining DC vaccination and bortezomib treatment.
Minimal residual disease (MRD) after allogeneic stem cell transplantation (SCT) for Ph+ acute lymphoblastic leukemia (ALL) is predictive of relapse. Imatinib administration subsequent to SCT may ...prevent relapse, but the role of scheduling and its impact on outcome are not known. In a prospective, randomized multicenter trial, we compared the tolerability and efficacy of post-transplant imatinib administered either prophylactically (arm A; n=26) or following detection of MRD (arm B; n=29). Prophylactic imatinib significantly reduced the incidence of molecular recurrence after SCT compared with MRD-triggered imatinib (40% vs 69%; P=0.046). Median duration of PCR negativity was 26.5 and 6.8 months, respectively (P=0.065). Five-year survival in both interventional groups was high (80 and 74.5%), despite premature discontinuation of imatinib in the majority of patients because of poor tolerability. Relapse probability was significantly higher in patients who became MRD positive (P=0.017). In conclusion, post-transplant imatinib results in a low relapse rate, durable remissions and excellent long-term outcome in patients with BCR-ABL1-positive ALL irrespective of whether it is given prophylactically or MRD-triggered. Reappearance of BCR-ABL1 transcripts early after SCT or at higher levels identifies a small subset of patients who do not benefit sufficiently from imatinib, and in whom alternative approaches should be explored.
TBI-based preparative regimens are considered as standard conditioning therapy for allogeneic stem cell transplantation (AHSC) in patients with ALL. We investigated toxicity and efficacy of a ...non-TBI-based regimen consisting of treosulfan, etoposide and cyclophosphamide for ALL within a prospective study. Major inclusion criteria were CR and non-eligibility for TBI. Fifty patients with a median age of 46.5 years (range, 18-64) were included. Donors were HLA-identical sibling (n=8), matched (n=42) or mismatched (n=10) unrelated. The toxicity was moderate, resulting in a cumulative incidence of non-relapse mortality (NRM) at 1 year of 8% (90% confidence interval: 2-15%). Acute GvHD grade II-IV and grade III/IV was noted in 53% and 14%, respectively. Chronic GvHD at one year was seen in 41%. After a median follow-up of 24 months the cumulative incidence of relapse was 36% (90% confidence interval: 24-48) and 51% (90% confidence interval: 37-65) at 1 and 2 years, respectively. The estimated 2-year disease-free and overall survivals were 36 and 48%, respectively. Treosulfan, etoposide and cyclophosphamide followed by AHSC has a favorable toxicity profile with low NRM and therefore represents a potential alternative regimen for ALL in 1. CR (NCT00682305).
We performed a retrospective assessment of patient- and transplant-specific characteristics and outcomes for 4142 patients undergoing allogeneic haematopoietic cell transplant for myelofibrosis ...between 1995 and 2018 across 278 centres. Activity increased steadily across the four analysed eras (<2006, 2006-2010, 2011-2014 and 2015-2018). Median recipient age increased over time between the earliest and most recent cohort (49.4 years (range, 20.1-68) versus 59.3 years (range, 18.1-78.1). Increasing number of patients with a Karnofsky performance status <90 underwent transplant over time. Increased utilisation of matched unrelated donors was apparent (<2006, 22.5% versus 2015-18, 45.2%; p < 0.001). Decreased use of myeloablative conditioning, increased use of busulphan-based platforms and anti-thymocyte globulin was evident. Of note, rates of acute (a)GVHD grade II-IV by day +100 decreased over time (p = 0.027) as did rates of chronic (c) GVHD, predominantly extensive cGVHD (<2006, 36% (31-41%) versus 2015-18, 23% (21-25%); p = 0.001). Overall, significant factors associated with worse overall survival and non-relapse mortality (NRM) remained older age, use of donors other than matched sibling, recipient CMV seropositivity and a lower Karnofsky performance status (<90). Multivariable analysis demonstrated improvements in overall survival and reductions in relapse risk over time with stable NRM rates despite increasing numbers of older, less fit patients and use of unrelated donors.
Chimerism analysis has become a routine method to document engraftment and also for detection of residual disease. PCR-based procedures using STR analysis, especially commercially available multiplex ...assays, are frequently used. However, these assays have been optimized for forensic purposes and do not necessarily fulfil all needs for chimerism analysis. To improve these analyses, data on the level of informativity of STR systems in the context of chimerism analysis would be helpful. We evaluated 27 STR markers for their informativity in 203 patients and their HLA-matched related donors. These STRs included 18 from different multiplex kits, whereas nine were selected from the literature or STR databases. The STR profiles were ranked from Type 1 (not informative) to Type 5 (best suited for chimerism analysis). According to this ranking, the informativity of the STR systems was found highly variable, ranging from 4.4 to 49.0% Type 5 constellations. Among the most informative STRs were Penta E, SE33, D2S1338 and D18S51. Informativity of an STR was correlated with the degree of heterozygosity (r=0.86; P=0.0001), but not with the total number of alleles present. These data indicate that selection of suitable STR markers is important to improve diagnostics based on STR analysis.
PDF
