Peripheral Blood Dendritic Cell Subsets of Patients with Type I Gaucher’s Disease Are Decreased in Number but Functionally Normal.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3810-3810 ◽  
Author(s):  
Argiris Symeonidis ◽  
Ilina Mitseva ◽  
Theodoros Marinakis ◽  
Constantina Repa ◽  
Alexandra Kouraklis ◽  
...  

Abstract Introduction - Aims: Gaucher’s disease is a lysosomal storage disorder, in which undigested glucocerebroside is deposited in the cytoplasm of mature macrophages, which accumulate in the bone marrow and the reticuloendothelial system. Dendritic cells (DC) are bone-marrow-derived leukocytes, originating from the pluripotent hematopoietic stem cell, via different developmental pathways, related to myeloid or lymphoid lineage. They belong to the monocyte-macrophage system and are specialized for the uptake, processing, transport and presentation of antigens to T-cells. There is no information about the functional capacity of DC among patients with lysosomal storage disorders. We therefore, investigated in the status of blood DC precursor populations as well as the potential of bone marrow (BM)-derived progenitor cells to produce mature DC in patients with Gaucher’s disease. Patients and methods: Samples of heparinized PB and/or BM were obtained from 11 patients with type I Gaucher’s disease and 15 healthy volunteers, after informed consent. Nine patients were studied before any kind of treatment and the remaining 2 had been treated with imiglucerase 40 IU/kg of body weight at monthly intervals, for 24 months. All patients were anemic and thrombocytopenic, but none had severe bone disease. The myeloid DC (MDC) precursors and the more specialized cell type, the plasmacytoid DC (PDC) were detected in the peripheral blood by flow cytometry, based on the expression of immunoglobulin-like transcript (ILT)-3, together with lineage-specific markers CD3, CD56, CD14, CD16 and CD11c. The potential of PB monocytes, as DC precursors, and of BM CD34+ progenitors to differentiate into mature DC was studied in culture systems. Generated mature DC were immunophenotyped, and tested for their dextran-endocytic capacity, as well as for their stimulatory activity against allogeneic T-cells in mixed cultures. Results: Both, MDC and PDC from peripheral blood of patients with Gaucher’s disease were decreased, when compared to controls (MDC 0.20±0.11% vs. 0.33±0.14%, p=0.02 and PDC 0.19±0.15% vs. 0.40±0.17%, p=0.005). The yield of monocyte-derived DC (MoDC), obtained after GM-CSF and IL-4 stimulation, was lower than in controls (4.9±3.5% vs. 8.2±4%, p=0.012), although no difference was found in the percentage of monocytes initiating the culture. However, the immunophenotype profile, estimated by CD1a, CD40, CD54, CD80, CD83, and HLA-DR expression, the endocytic capacity, and the allo-stimulatory capacity of immature, and of TNFα- or LPS-stimulated mature MoDC were similar to those obtained by healthy controls. In addition, BM-derived CD34+ cells, differentiated in the presence of GM-CSF, SCF, TNF-α and IL-4 into mature DC, did not differ in number, phenotype and allo-stimulatory activity from those of controls. Conclusive remarks: Our findings suggest that in patients with type I Gaucher’s disease, mainly quantitative defects of DC system are present, demonstrated by decreased circulating DC precursors of both, MDC and PDC type. Moreover, with the exception of decreased MoDC production, no additional functional/qualitative defects of both, CD34-DC and MoDC, concerning their membrane immunophenotype, endocytic and allostimulatory capacity were detected.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4010-4010
Author(s):  
H. Angharad Watson ◽  
Rebecca J Holley ◽  
Kia J Langford-Smith ◽  
Fiona L Wilkinson ◽  
Toin H van Kuppevelt ◽  
...  

Abstract Abstract 4010 The primary axis of migration for transplanted hematopoietic stem and progenitor cells (HSPC) is CXCL12/CXCR4. Heparan sulphate (HS) is required for CXCL12 presentation and receptor binding, but the functional role of HS is poorly defined. The alpha-L-iduronidase knockout mouse (Idua−/−) accumulates HS and dermatan sulphate, recapitulating the neurodegenerative lysosomal storage disease Mucopolysaccharidosis I Hurler (MPSIH). MPSIH is primarily treated with HSPC transplant, but clinical experience suggests a historical engraftment defect in patients. We show significantly reduced HSPC migration in Idua−/− recipients and under limiting engraftment conditions we show a significant haematopoietic engraftment defect in Idua−/− recipients. No significant donor cell effect was observed. Bone marrow but not peripheral blood CXCL12 levels are slightly elevated in Idua−/− mice. CFU frequency in BM is unchanged between genotypes but reduced significantly in peripheral blood of Idua−/− mice. In whole bone marrow, and on mesenchymal stem cells from Idua−/− mice, HS is present in significant excess, particularly in extracellular matrix, and cell surface locations, with significant increases in all sulphation modifications, especially 2-O-sulphation. Finally we show that excess HS, and particularly HS with increased 2-O -sulphation, functionally inhibit haematopoietic progenitor cell migration in vitro. These data provide novel insight into the influence of highly sulphated HS in CXCL12 mediated haematopoietic progenitor cell migration and help to explain why HSCT engraftment has been historically low in MPSIH. Disclosures: No relevant conflicts of interest to declare.


2015 ◽  
Vol 48 (4) ◽  
pp. 216-219 ◽  
Author(s):  
Ricardo Andrade Fernandes de Mello ◽  
Melissa Bozzi Nonato Mello ◽  
Laís Bastos Pessanha

Abstract Objective: To evaluate by magnetic resonance imaging changes in bone marrow of patients undergoing treatment for type I Gaucher’s disease. Materials and Methods: Descriptive, cross-sectional study of Gaucher’s disease patients submitted to 3 T magnetic resonance imaging of femurs and lumbar spine. The images were blindly reviewed and the findings were classified according to the semiquantitative bone marrow burden (BMB) scoring system. Results: All of the seven evaluated patients (three men and four women) presented signs of bone marrow infiltration. Osteonecrosis of the femoral head was found in three patients, Erlenmeyer flask deformity in five, and no patient had vertebral body collapse. The mean BMB score was 11, ranging from 9 to 14. Conclusion: Magnetic resonance imaging is currently the method of choice for assessing bone involvement in Gaucher’s disease in adults due to its high sensitivity to detect both focal and diffuse bone marrow changes, and the BMB score is a simplified method for semiquantitative analysis, without depending on advanced sequences or sophisticated hardware, allowing for the classification of the disease extent and assisting in the treatment monitoring.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1653-1653
Author(s):  
Nobuyuki Onai ◽  
Aya Onai ◽  
Markus G. Manz

Abstract Most type-I interferon producing cells (IPCs) and dendritic cells (DCs) are non-dividing cells with a short in vivo half-live of several days, and thus need to be continuously replaced. A common differentiation pathway for IPCs and DCs, and accordingly, the existence of common IPC and DC progenitors remains controversial. Flt3-ligand (Flt3L) is a non-redundant cytokine for in vivo IPC and DC development: IPC and DC differentiation potential is confined to Flt3+-hematopoietic progenitors; Flt3L KO mice show massively reduced IPCs and DCs. In contrast to Flt3, the “myeloid” cytokines GM-CSF and M-CSF seem to be less relevant in steady-state IPC and DC differentiation, however, they might be critically important in inflammatory conditions. To identify a candidate common IPC and DC progenitor population, we evaluated Flt3 and “myeloid” cytokine receptor expression in mouse bone marrow. We found that c-kitintlin− cells contained a Flt3+M-CSFR+ fraction that in Flt3L supplemented cultures gave rise to about 95% pure CD11c+MHC class II+ cells, consisting of both CD11c+B220+ IPCs and CD11c+B220− DCs, at a efficiency comparable to that of hematopoietic stem cells. In the presence of GM-CSF, Flt3+M-CSFR+c-kitintlin− cells gave rise to CD11c+CD11b+ DCs but not CD11c−CD11b+ macrophages/monocytes. Furthermore, Flt3+M-CSFR+c-kitintlin− cells possessed very poor, if any activity in myeloid colony forming assays, and lacked pre-B cell colony forming activity. In both, lethally and sub-lethally irradiated mice, transferred Flt3+M-CSFR+c-kitintlin− cells differentiated into CD11c+B220+ IPCs, CD11c+CD8α+, and CD11c+CD8α− conventional DC subsets, while no other hematopoietic cells were detectable. In vivo reconstitution and CFSE-labeling experiments showed that Flt3+M-CSFR+c-kitintlin− cells extensively proliferate in the lethally irradiated mice, reaching peak progeny levels of IPC and DC at day 10 after transplantation, indicating high proliferative, but limited self-renewal capacity of these cells. Quantitative RT-PCR analysis revealed high expression of DC and IPC-development affiliated genes (such as PU.1, STAT3, GM-CSFR, and CX3CR1), but no lymphoid- and erythroid-development affiliated gene transcription. These data suggest the existence of common developmental intermediates for both IPCs and DCs in mouse bone marrow, and thus might provide new insights into the regulation of IPC and DC differentiation in steady-state and inflammation.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1489-1489
Author(s):  
Takamasa Katagiri ◽  
Zhirong Qi ◽  
Yu Kiyu ◽  
Naomi Sugimori ◽  
J. Luis Espinoza ◽  
...  

Abstract Abstract 1489 Poster Board I-512 The hematopoietic stem cell (HSC) differentiation pathway in humans remains largely unknown due to the lack of an appropriate in vivo assay allowing the growth of HSCs as well as of clonal markers that enable the tracing of their progenies. Small populations of blood cells deficient in glycosylphosphatidylinositol-anchored proteins (GPI-APs) such as CD55 and CD59 are detectable in approximately 50% of patients with aplastic anemia (AA) and 15% of patients with refractory anemia (RA) of myelodysplastic syndrome defined by the FAB classification. Such blood cells with the paroxysmal nocturnal hemoglobinuria (PNH) phenotype (PNH-type cells) are derived from single PIGA mutant HSCs and their fate depends on the proliferation and self-maintenance properties of the individual HSCs that undergo PIG-A mutation by chance (Blood 2008;112:2160, Br J Haematol 2009 in press) Analyses of the PNH-type cells from a large number of patients on the diversity of lineage combination may help clarify the HSC differentiation pathway in humans because PIG-A mutant HSCs in patients with bone marrow failure appear to reflect the kinetics of healthy HSCs. Therefore, different lineages of peripheral blood cells were examined including glycophorin A+ erythrocytes (E), CD11b+ granulocytes (G), CD33+ monocytes (M), CD3+ T cells (T), CD19+ B cells (B), and NKp46+ NK cells (Nk) from 527 patients with AA or RA for the presence of CD55−CD59− cells in E and G, and CD55−CD59−CD48− cells in M,T, B, Nk with high sensitivity flow cytometry. Two hundred and twenty-eight patients (43%) displayed 0.003% to 99.1% PNH-type cells in at least one lineage of cells. The lineage combination patterns of PNH-type cells in these patients included EGM in 71 patients (31%), EGMTBNk in 43 (19%), EG in 37 (16%), T alone 14 (6%), EGMBNk in 11 (5%), G alone in 10 (4%), GM in 10 (4%), EGMNk in 7 (3%), EGMT in 7 (3%), EGMB in 6 (3%), EM in 5 (2%), EGMTB in 3 (1%), EGNk in 1 (0.4%), EGMTNk in 1 (0.4%), GMTB in 1 (0.4%), and GT in 1 (0.4%) (Table). All patterns included G or M, except for 14 patients displaying PNH-type T cells alone. No patients showed TB or TBNk patterns suggestive of the presence of common lymphoid progenitor cells. Peripheral blood specimens from 123 patients of the 228 patients possessing PNH-type cells were examined again after 3 to 10 months and all patients showed the same combination patterns as those revealed by the first examination. PIG-A gene analyses using sorted PNH-type cells from 3 patients revealed the same mutation in G and Nk for 1 patient and in G and T for 2 patients. These findings indicate that human HSCs may take a similar differentiation pathway to that of murine HSCs, the ‘myeloid-based model’ that was recently proposed by Kawamoto et al. (Nature 2008; 10:452), though the cases with PNH-type T cells alone remain to be elucidated. Table. Lineages of cells containing PNH-type cells in patients with AA or RA. The number in the parenthesis denotes the proportion of patients showing each combination pattern in the total patients possessing PNH-type cells. (+ ; presence of PNH-type cells) Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3147-3147 ◽  
Author(s):  
Roni Tamari ◽  
Sheetal Ramnath ◽  
Deborah Kuk ◽  
Craig S. Sauter ◽  
Doris M Ponce ◽  
...  

Abstract Abstract 3147 Introduction: Poor graft function (PGF) without immune rejection, defined as persistent cytopenias with hypocellular marrow and full donor myeloid chimerism, can be a life-threatening complication after allogeneic HSCT. It is commonly caused by viral infectious, myelosuppressive drugs like antivirals, and graft-vs-host disease (GvHD). Treatment options include supportive therapy with transfusions and growth factors and in severe cases administration of additional hematopoietic stem cells (HSCs) from the same donor without conditioning (stem cell boost). The incidence, natural history, and the indications for stem cell boost therapy are not well defined. Aims: To assess the incidence, etiologies, and indications for stem cell boost for PGF in a homogeneous group of patients with advanced MDS and AML who underwent TCD HSCT from matched or mismatched related or unrelated donors after conditioning with the same myeloablative regimen. Patients and methods: Poor graft function was defined as persistent neutropenia (ANC <1,000 μL and G-CSF administration x3 in 30 days), thrombocytopenia (platelets <50,000 μL or platelets transfusion × 4 in 30 days), and/or hemoglobin <8 g//dL after engraftment with hypocellular BM and full donor myeloid chimerism. Severe PGF was defined as ANC <500 μL, red cell transfusion-dependent anemia with reticulocytopenia of < 20,000 μL, and platelets <20,000 μL. The patient population in which this study was done included 42 patients enrolled between 09/2009 and 05/2012 in a phase 2 trial of palifermin peri-transplant to reduce transplant-related mortality. The median age was 57.5 years (1–65). All patients received the same myeloablative conditioning regimen with busulfan, melphalan, fludarabine, rabbit ATG and palifermin peri-transplant. G-CSF mobilized donor peripheral blood stem cells underwent CD34+ selection and depletion of T cells using CliniMACS immunomagnetic selection columns (Milteny Biotec). Donors were HLA matched (31; 13 related and 18 unrelated) or mismatched unrelated (11). Chimerism was determined in bone marrow as well as neutrophils, B cells, and T cells by short tandem repeat analysis on DNA extracted from bone marrow and peripheral blood cell subsets. Results: Forty-one patients were evaluable for this analysis; 1 patient was not included as he rejected the allograft shortly after engraftment. There were 8 cases of PGF with a cumulative incidence (CI) at 1 year of 18% (13% HLA matched, 33% HLA mismatch). The etiology was infection in 7 cases, and unknown in the 8th case. This patient presented with presumed autoimmune anemia and thrombocytopenia associated with a hypercellular marrow and did not respond to multiple lines of therapies. Her marrow became later hypocellular and met the criteria for PGF. None of the PGF cases in this series was associated with GvHD at the time of diagnosis of PGF. The infectious etiologies included: 6 viral infections and 1bacterial sepsis + myelosuppressive drugs. The most common viral etiology associated with PGF was CMV (50%). The 1-year CI of PGF in CMV seropositive patients was 25% and in CMV seronegative patients was 14%. Of note, HHV6 viremia was detected in patients with PGF. HHV6 is not routinely monitored, however, making it difficult to establish a causative role. All patients had moderate PGF at diagnosis and 3 cases had worsening of cytopenias and met the criteria for severe PGF. To date, 3 PGF patients have died from EBV-PTLD, adenovirus infection or GVHD (developed after CMV treatment with liposomal cidofovir), 3 continue to suffer from PGF and 2 patients are alive with recovered good blood counts after eradication of CMV. Of the 3 patients with persistent PGF, one received a TCD boost with no response, and 2 continued to be treated for CMV viremia. A stem cell boost was indicated if pancytopenia persisted despite eradication of cause of the PGF. In this small series, there were not enough events to evaluate association between PGF and CD34 cell dose, CD3 cell dose or day 100 T-cell chimerism. Conclusions: In this homogenous population of patients with MDS who underwent TCD allogeneic HSCT, the incidence of PGF is about 20%. The most common cause was viral infection with predominance of CMV. Therefore, strategies to prevent CMV reactivation in patients undergoing allogeneic HSCT has the potential to reduce the risk of PGF and avoid the need for infusion of additional stem cells. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 143-143 ◽  
Author(s):  
Saar Gill ◽  
Sarah K Tasian ◽  
Marco Ruella ◽  
Olga Shestova ◽  
Yong Li ◽  
...  

Abstract Engineering of T cells with chimeric antigen receptors (CARs) can impart novel T cell specificity for an antigen of choice, and anti-CD19 CAR T cells have been shown to effectively eradicate CD19+ malignancies. Most patients with acute myeloid leukemia (AML) are incurable with standard therapies and may benefit from a CAR-based approach, but the optimal antigen to target remains unknown. CD123, the IL3Rα chain, is expressed on the majority of primary AML specimens, but is also expressed on normal bone marrow (BM) myeloid progenitors at lower levels. We describe here in vitro and in vivostudies to evaluate the feasibility and safety of CAR-based targeting of CD123 using engineered T cells (CART123 cells) as a therapeutic approach for AML. Our CAR consisted of a ScFv derived from hybridoma clone 32716 and signaling domains from 4-1-BB (CD137) and TCR-ζ. Among 47 primary AML specimens we found high expression of CD123 (median 85%, range 6-100%). Quantitative PCR analysis of FACS-sorted CD123dim populations showed measurable IL3RA transcripts in this population, demonstrating that blasts that are apparently CD123dim/neg by flow cytometry may in fact express CD123. Furthermore, FACS-sorted CD123dimblasts cultured in methylcellulose up-regulated CD123, suggesting that anti-CD123 immunotherapy may be a relevant strategy for all AML regardless of baseline myeloblast CD123 expression. CART123 cells incubated in vitro with primary AML cells showed specific proliferation, killing, and robust production of inflammatory cytokines (IFN-α, IFN-γ, RANTES, GM-CSF, MIP-1β, and IL-2 (all p<0.05). In NOD-SCID-IL2Rγc-/- (NSG) mice engrafted with the human AML cell line MOLM14, CART123 treatment eradicated leukemia and resulted in prolonged survival in comparison to negative controls of saline or CART19-treated mice (see figure). Upon MOLM14 re-challenge of CART123-treated animals, we further demonstrated robust expansion of previously infused CART123 cells, consistent with establishment of a memory response in animals. A crucial deficiency of tumor cell line models is their inability to represent the true clonal heterogeneity of primary disease. We therefore engrafted NSG mice that are transgenic for human stem cell factor, IL3, and GM-CSF (NSGS mice) with primary AML blasts and treated them with CART123 or control T cells. Circulating myeloblasts were significantly reduced in CART123 animals, resulting in improved survival (p = 0.02, n=34 CART123 and n=18 control animals). This observation was made regardless of the initial level of CD123 expression in the primary AML sample, again confirming that apparently CD123dimAML may be successfully targeted with CART123 cells. Given the potential for hematologic toxicity of CART123 immunotherapy, we treated mice that had been reconstituted with human CD34+ cells with CART123 cells over a 28 day period. We observed near-complete eradication of human bone marrow cells. This finding confirmed our finding of a significant reduction in methylcellulose colonies derived from normal cord blood CD34+ cells after only a 4 hour in vitro incubation with CART123 cells (p = 0.01), and was explained by: (i) low level but definite expression of CD123 in hematopoietic stem and progenitor cells, and (ii) up-regulation of CD123 upon myeloid differentiation. In summary, we show for the first time that human CD123-redirected T cells eradicate both primary human AML and normal bone marrow in xenograft models. As human AML is likely preceded by clonal evolution in normal or “pre-leukemic” hematopoietic stem cells (Hong et al. Science 2008, Welch et al. Cell 2012), we postulate that the likelihood of successful eradication of AML will be enhanced by myeloablation. Hence, our observations support CART-123 as a viable therapeutic strategy for AML and as a novel cellular conditioning regimen prior to hematopoietic cell transplantation. Figure 1. Figure 1. Disclosures: Gill: Novartis: Research Funding; American Society of Hematology: Research Funding. Carroll:Leukemia and Lymphoma Society: Research Funding. Grupp:Novartis: Research Funding. June:Novartis: Research Funding; Leukemia and Lymphoma Society: Research Funding. Kalos:Novartis: Research Funding; Leukemia and Lymphoma Society: Research Funding.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5195-5195
Author(s):  
Lulu Lu ◽  
Yongping Song ◽  
Baogen Ma ◽  
Xiongpeng Zhu ◽  
Xudong Wei ◽  
...  

Abstract Background and objectives: Normal human bone marrow (BM), cord blood (CB) and mobilized peripheral blood (MPB) are the most commonly used sources for allogeneic hematopoietic stem cell transplantation (HSCT). The aim of this study was to detect the expression of CXCR4 on CD34+ cells and to assess the distribution of lymphocyte subsets in each type allograft. Methods: CD34+ cells were separated from BM (n=30), CB (n=30) and MPB (n=30) by the CD34 MultiSort Kit immunomagnetic bead system. The expression of CXCR4 on CD34+cells was assayed by double color flow cytometry. The lymphocyte subsets in each type of allograft were detected by three-color flow cytometry. The groups of monoclonal antibodies were used as the following: CXCR4-PE/CD34−Pecy5, CD8−FITC/CD4−R-PE/CD3−TC, CD45RA-FITC/CD45RO-PE/CD4−Pecy5, CD45RA-FITC/CD45RO-PE/CD8−Pecy5, and CD3−FITC/CD16+56-PE. Isotype-specific antibodies were used as controls. Results: The expression of CXCR4 of cord blood and mobilized peripheral blood CD34+ cells was lower than that of bone marrow cells (BM 40.21%±6.72%, CB 20.93%±3.96%, MPB 20.93%±3.96%, P &lt;0.05). The difference between cord blood and mobilized peripheral blood was not significant (P&gt;0.05). The CD3+CD8low and CD3+CD4−CD8low subsets were higher in BM than that of CB and MPB (BM 8.61%±1.40%, CB 3.31%±0.88%, MPB 5.11%±0.76%,P&lt;0.01). The relative frequencies of the naïve CD45RA+ CD45RO− phenotype among CD4+ and CD8high T cells were highest in CB, and it was higher in MPB than in BM grafts (BM 28.09%±4.52%, 41.86 %±3.31%; CB83.83%±12.24%, 86.69%±6.12%; MPB 43.58%±4.54%, 57.64%±4.77%, P&lt;0.01). Naïve T cells (CD45RA+ CD45RO−) were mobilized preferentially compared to memory T cells (CD45RA− CD45RO+)(P &lt;0.01); The relative frequencies of NKT (CD3+CD16+56+) among lymphocytes were lower in CB than that in BM and MPB (CB 0.77±0.19, BM4.15±1.10, MPB 4.13±0.84, P&lt;0.01). Conclusion: BM, CB and MPB allografts differ widely in cellular makeup of CD34+ cells and lymphocyte subsets, which are associated with the distinct characteristics after allogeneic HSCT from different allogeneic hematological sources.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4699-4699
Author(s):  
Shicheng Yang ◽  
Xiao Huang ◽  
Hongyan Lu ◽  
Amandeep Salhotra ◽  
Alexander Wendling ◽  
...  

Abstract Abstract 4699 Introduction: Umbilical cord blood cells (UCB) from allogeneic donors have been established as an alternative source for HSC transplantation in patients who lack suitably HLA matched bone marrow or peripheral blood stem cells from adult donors. Transplantation using 2 unit UCB has been shown to compensate the low engraftment and slow hematopoietic recovery resulting from 1 unit UCB transplantation in full stature adult patients. At present, there are no unit specific factors that reliably predicts for the “winning unit” in 2 unit UCB transplantation, e.g. cell viability, number of infused total nucleated cells, CD34+ or CD3+ cells, sex mismatch, ABO blood group, and degree of HLA mismatch. In vivo mouse models suggest that CD34 negative subsets play an important role. Among CD34 negative subsets, CD8 T subset accounts for approximately 34.0+/−23.3% of T lymphocytes from UCB. In bone marrow transplantation CD8 T cells have been found to facilitate donor hematopoietic cell engraftment. Moreover, it has been reported that 1 dominant unit coincides with a specific CD8 T cell response against the non-engrafted unit which was not observed from CD4 or NK cells. Methods: In this study, we used volunteer donated UCB research units (kindly provided by P. Rubinstein, MD, New York Blood Center). Mononuclear cells (MNC) were purified by Ficoll gradient centrifugation, and CD3 T cells were isolated with CD3 MicroBeads (Miltenyi Biotec; autoMACS). The purified CD3 (confirmed by FACS >95% purity) cells were labeled with CFSE and DDAO-SE. After labeling, the cells from two different donors were mixed in 96-well U-bottom plates for continued culture in 37 °C 5% CO2. The expansion from each labeled donor cells was evaluated using flow cytometry; the dead cells were gated out using propidium iodide, and the data was analyzed using FlowJo software. For proper T cells activation, we also compared different activation conditions using i.) anti-CD3/CD28 Beads, ii.) anti-CD3 antibody plus anti-CD28 antibody, and iii.) cytokine IL-2. The schematic illustration of methods is shown in Figure 1. Results and discussion: We noted that T cells from UCB are primarily at naïve stage as determined by CD45RA (93.8 +/− 7.11%) and CCR7 (84.9 +/− 12.0%) expression. We also determined the optimal activation condition using a modified mixed lymphocyte reaction from 2 UCB units. Four days after incubation, the proliferation from 2 units labeled with CFSE and DDAO-SE could be reproducibly distinguished using FL1 channel for CFSE and FL4 channel for DDAO-SE (Figure 1). The optimal concentration for labeling using CFSE (1 mM) and DDAO (1 μM or 3 mM) was determined by titration. To avoid cell toxicity resulting from CFSE and DDAO-SE labeling, as well as self-crossing from each donor using two dyes, we examined additional mixed lymphocyte analyses in which each donor was labeled with CFSE or DDAO-SE respectively and vice versa. As shown in Figure 1, we found consistently that the predicated dominant unit accounted for the majority of culture (73.2% stained with DDAO; 63.5% stained with CFSE) after 4 days co-culture. The dominance was not correlated with cell proliferation indicated by the proliferation index (1.12 for dominant and 1.48 for another unit). After confirmation of this in vitro assay, further studies were conducted to evaluate the IFN-γ release of 2 UCB units in this optimized mixed lymphocyte assay in the condition using cytokine IL-2. Interestingly, we could only detect IFN-γ by intracellular staining in one unit when co-culture was set-up using CD3 T cells from each unit; the expression of IFN-γ was not detected when we used CD3 T cells from 1 unit. The correlation between dominance and the expression of IFN-γ is currently under investigation. Conclusion: UCB Transplantation is an important alternative for patients lacking bone marrow or peripheral blood stem cell donors. With the establishment of this novel modified mixed lymphocyte in vitro assay for prediction of the “winning” immune dominant unit, routine analyses can be performed to guide unit selection. Further interventions can be exploited to preferentially treat the expected dominant unit with glycosylation, cytokines, prostaglandins, or C3a compliments to further enhance hematopoietic stem cells trafficking and engraftment to the marrow. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2395-2395
Author(s):  
Shabnam Arsiwala ◽  
Wei Ding ◽  
Hong-Gang Wang

Abstract Bone marrow niche cells, specifically the Leptin-receptor-expressing perivascular stromal cells (LepR+), CXCL12-abundant reticular cells (CAR), and endothelial cells play an important role in the maintenance and self-renewal functions of hematopoietic stem cells (HSCs). This maintenance function provided by the niche cells is mediated by a number of secretory-related molecules such as stem cell factor (SCF), CXCL12 and Angiopoietin. In addition, functional autophagy within HSCs is known to play a critical role for maintaining HSC homeostasis, as the loss of ATG7 in HSCs leads to loss of normal HSC functions and severe myeloproliferation. However, it remains unclear as to how hematopoiesis will be affected if autophagy is selectively blocked in bone marrow niche cells. To investigate the effect of autophagy deficiency within bone marrow niche cells on hematopoiesis, we generated a knockout mouse model allowing for a selective ablation of an autophagy-essential protein, ATG5, in LepR+ perivascular stromal cells. We have confirmed that the deletion of Atg5 is indeed restricted to LepR+ cells, and that the loss of ATG5 is sufficient to block autophagic function, as evident through the accumulation of p62 protein. We found that the white blood cell count (WBC) is significantly reduced in 16-week old male ATG5 KO mice compare to wild type (wt) littermate control mice (p<0.05). Further, the myeloid population (CD11b+ Ly6G+) in both bone marrow and peripheral blood is significantly decreased in ATG5 KO mice (p value < 0.05, ATG KO vs. wt control). WBC count continues to decline in 24-week old ATG5 KO male mice (p=0.02) but not in female mice (p=0.58). Both LSK (Lin- Sca-1+ c-Kit+) and long term HSC (LT-HSCs, CD150+ CD48- LSK) populations are decreased in both 16-week and 24-week old male mice; however, this trend did not reach statistical significance (p>0.05). Although the absolute cell count of lymphocytes, including B and T cells (CD19+ and CD3+, respectively) in peripheral blood, is significantly dropped in ATG5 KO mice compared to wt controls, there is no significant change of mature B and T cells in bone marrow. These preliminary results suggest that deletion of a key autophagy regulator in LepR+ bone marrow niche cells will cause leukopenia. The underlying mechanism is currently under investigation and it will help us to better understand the role of autophagy in hematopoiesis within the bone marrow microenvironment. Disclosures No relevant conflicts of interest to declare.


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