Interactions between the haematopoietic stem cell and the myeloid microenvironment in aplastic anaemia

In patients with aplastic anaemia that respond to immunosuppressive therapy, quantitative, morphological and functional haematologic derangement have been reported. To explain these findings, abnormalities in the marrow stroma or the stem cell have been postulated. To define the relative contribution of each of the latter, the integrity of the bone marrow from sixteen patients that responded to anti-lymphocyte globulin and high dose methyl prednisolone was compared to normal individuals. Bone marrow mononuclear cells were divided into two fractions. From the first, stroma was cultured in aMEM containing 12.5% of both horse and foetal calf serum and 10-5 M hydrocortisone at 37° C in 5% CO2 in 90% humidity. The medium was changed weekly. Upon confluence, these stromal layers were studied morphologically and with cytospin preparations stained with Sudan black, 0 red oil, alkaline and acid phosphatases. The remainder was monocyte and lymphocyte depleted, CD 34+ progenitors were selected with paramagnetic beads and the population morphologically and immunophenotypically defined. To determine the functional status, control or patient CD 34+ progenitors, were suspended for two hours on normal or aplastic stroma for adherence to take place. The non-adhesive fraction was decanted by standardised washing and cultured for fourteen days in the presence of PHA-conditioned medium in the CFU-gm assay. Strama-adherent progenitors were covered with 0.3% agar and cultured for five days. Aggregates with more than twenty cells were scored (CFU-bl). The remaining CD 34+ cells were cultured in the mixed colony assay with combinations of recombinant cytokines belonging to the G protein super-family and the tyrosine kinase group in dose response studies. Light density cells from patients with treated aplasia contained significantly fewer CD 34+ cells than those present in the control suspensions (mean 0.65%, SD 0.35% vs 1.62%, SD 1.4%; p= 0.002). Normal and aplastic stroma became confluent at three and four weeks. There was no difference on the morphology or the cytochemical stains between the two groups. Functionally, aplastic bone marrow stroma supported CFU-bl formation no differently from normal layers. However, CD 34+ precursors from the patients cultured on control stroma resulted in significantly fewer CFU-bl (p= 0.0002,) and CFU-gm (p= 0.0009). This work provides original evidence supporting the reduced clonogenicity of the corresponding populations of CFU-bl from patients with aplasia is unrelated to attachment to the stroma, but intrinsic to the CD 34+ cells. Moreover, this study shows for the first time that exposure of these progenitors to growth factors belonging to the G protein and tyrosine kinase receptor families have defective responses, correctable only at supra physiological concentrations, while effects on combinations containing c-kit ligand, appear preserved. Following immunosuppressive therapy, the bone marrow is repopulated by a hypoproliferative progenitor cell population which responds suboptimally to physiological cytokine stimulation. This suggests that abnormal interactions between receptors and their ligands or alterations in the signal transduction for cell division by the cytokines belonging to the G superfamily lead to suboptimal growth

The functional significance of the Duffy negative polymorphism

I investigated the impact of DARC expression on haematopoiesis using DARC-deficient (DD) mice and developed humanised transgenic DARC models expressing the $FYB(ES)$ and $FYB$ human genes. I developed murine irradiation chimeras with differential DARC expression and showed that the absence of erythroid DARC but continued DARC endothelial expression was associated with reduced peripheral blood neutrophil counts. FYB(ES)TG mice showed reduced peripheral neutrophil counts and expansion of BM myelopoiesis, and reduced lymphopoiesis and erythropoiesis, compared to FYBTG mice. FYB(ES)TG and DD mice had reduced GMP cells and LSK cells, and proliferation and apoptosis of these cells were reduced. Microarray analysis of differentially expressed genes showed increased myeloid gene expression in GMP and LSK cells. Mixed irradiation chimeras showed that DD BM retained these changes, suggesting an intrinsic cell effect. Analysis of BM and serum showed a significant increase in G-CSF and eotaxin. Morphological analysis of myeloid cells in femur sections revealed increased myeloid cell clustering in DD and FYB(ES)TG mice. These data suggest that neutrophils are preferentially retained in the DD BM, possibly as a result of loss of optimal chemokine gradients created by erythroblast DARC which may favour neutrophil egress and thereby leading to peripheral neutropenia

Cancer/Testis Antigen Expression Panel Incorporating MAGEC1 and BAGE2 Predicts Multiple Myeloma Disease Stage and Severity

To provide a single molecular assay that could be used to easily stage Multiple Myeloma patients at diagnosis, we investigated the association between the simultaneous expression of 7 Multiple Myeloma-associated Cancer/Testis Antigens and biochemical parameters that are currently used for disease staging. We analysed the mRNA expression of MAGEC1, MAGEA3/A6, BAGE2, PRAME, NYESO1, SSX2 and PAGE by qualitative reverse transcription PCR using RNA extracted from diagnostic bone marrow samples from 39 patients covering the Multiple Myeloma disease continuum and compared this to levels of key biochemical parameters at diagnosis. We found that the Cancer/Testis Antigen panel was expressed in a specific order that was specifically associated with the severity of disease. This allowed the Cancer/Testis Antigens expression profile to successfully place the patient clearly into either stage I or stage III of the disease, with further sub-stratification in the stage III grouping. In addition, we putatively identified MAGEC1 expression as a confirmatory diagnostic marker for symptomatic Multiple Myeloma and clearly associated BAGE2 expression exclusively with stage III disease. We also demonstrated the novel finding of PAGE expression in Multiple Myeloma, with an association with more advanced disease. We suggest that this particular molecular Cancer/Testis Antigen panel can be used at diagnosis as a single test to clearly stage patient

ϒ production in p–Pb collisions at √sNN=8.16 TeV

ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio

An autologous dendritic cell vaccine polarizes a Th-1 response which is tumoricidal to patient-derived breast cancer cells.

Breast cancer remains one of the leading causes of cancer-associated death worldwide. Conventional treatment is associated with substantial toxicity and suboptimal efficacy. We, therefore, developed and evaluated the in vitro efficacy of an autologous dendritic cell (DC) vaccine to treat breast cancer. We recruited 12 female patients with stage 1, 2, or 3 breast cancer and matured their DCs with autologous tumour-specific lysate, a toll-like receptor (TLR)-3 and 7/8 agonist, and an interferon-containing cocktail. The efficacy of the vaccine was evaluated by its ability to elicit a cytotoxic T-lymphocyte response to autologous breast cancer cells in vitro. Matured DCs (≥ 60% upregulation of CD80, CD86, CD83, and CCR7) produced high levels of the Th1 effector cytokine, IL12-p70 (1.2 ng/ml; p < 0.0001), compared to DCs pulsed with tumour lysate, or matured with an interferon-containing cocktail alone. We further showed that matured DCs enhance antigen-specific CD8 + T-cell responses to HER-2 (4.5%; p < 0.005) and MUC-1 (19%; p < 0.05) tetramers. The mature DCs could elicit a robust and dose-dependent antigen-specific cytotoxic T-lymphocyte response (65%) which was tumoricidal to autologous breast cancer cells in vitro compared to T-lymphocytes that were primed with autologous lysate loaded-DCs (p < 0.005). Lastly, we showed that the mature DCs post-cryopreservation maintained high viability, maintained their mature phenotype, and remained free of endotoxins or mycoplasma. We have developed a DC vaccine that is cytotoxic to autologous breast cancer cells in vitro. The tools and technology generated here will now be applied to a phase I/IIa clinical trial

Monocyte derived dendritic cells have reduced expression of co-stimulatory molecules but are able to stimulate autologous T-cells in patients with MDS

Introduction: Research has implied that the immune system plays a role in the pathogenesis of MDS and that T-cells are reacting to tumour antigen present on the surface of the malignant cells. This could imply that the immune system could be utilized to generate immune based therapy. The aim of this pilot study was to examine the feasibility of studying this further by analysing the interaction of dendritic cells with T-cells in a small cohort of MDS patients. Methods: Dendritic cells were generated in 6 MDS patients and 9 controls by culturing monocytes with GM-CSF and IL-4. After activation with LPS and TNFα, the dendritic cells were analyzed for expression of co-stimulatory and activation antigens. Thereafter, they were co-cultured with T-cells and the T-cell response was examined by measuring the % change in expression of the activation antigen CD69. Results: MDS MoDC had reduced expression of HLA-DR (p=0.006), CD11c (p=0.0004), CD80 (p=0.03) and CD86 (p=0.003), while resting T-cells from MDS patients had higher expression of the activation antigen CD69 on all subsets. The % change in CD69 expression increased significantly for both the control and MDS T-cells after co-culture with allogeneic dendritic cells, however this change was lower in the MDS group. Despite the increased CD69 expression prior to culture, MDS MoDC significantly up-regulated CD69 expression on autologous T-cells to values that were statistically higher than control cells. Conclusion: This initial study suggests that the T-cells in MDS are able to respond to dendritic cells and are therefore probably not part of the malignant clone. It further implies that the dendritic cell population could be capable of presenting antigen and initiating an immune response and therefore further study is both feasible and warranted