Oligoclonal Expansion and T-Cells Subpopulations in Patients with Aplastic Anemia at Different Stages of the Disease

Abstract Background. The main mechanism of the bone marrow (BM) failure in idiopathic aplastic anemia (AA) has an immunomediated character. Researching the T-cell clone's effect in the AA pathogenesis is very relevant at the present time. Oligoclonal expansion of T cells is frequent in AA and the identification of immunodominant T-cell clones can correlate with the disease activity and may possibly serve as response predictor to immunosuppressive therapy (IST). The aim. To identify T-cells subpopulations, expression of PD-1 and PD-L1 on T-cells and TCR-Vβ repertoires by flow cytometry in different groups of AA patients. Methods. Thirty AA patients (pts) with median age of 30.5 (19-71), m/f ratio 1:1,3 were divided in 3 groups: pts with newly diagnosed (ND) AA (n=13), pts with overall response to IST (OR) (n=10), non-response pts (NR) for 2 and more lines of IST (n=7). Flow cytometry was performed with BD FACS Canto II. We used commercial kit (IOTest® Beta Mark TCR Vb Repertoire) for evaluation of TCR-Vβ repertoire in the bone marrow (BM) of these patients. We performed analysis of BM samples from healthy donors as a control group (n=8). Due to low amount of donor samples the maximal value each of the 24 subclones (for CD4+ (T-helpers - Th) and CD8+ cells (T-cytotoxic cells - TCL)) was accepted as threshold. We concluded the presence of clonal expansion if TCR subclone exceeded this threshold. We identified different T-cell subpopulations in all 3 groups of AA and healthy donors by flow cytometry: double positive T-cells (CD3+CD4+CD8+), double negative T-cells (CD3+CD4- CD8-), Th (CD3+CD4+), TCL (CD3+CD8+), NK-T-cells (CD3+CD56+) out of CD3+ cells. Among Th and TCL cells was determined naive T-cells (CD28+CD95-), effector T-cells (CD28-CD95+), memory T-cells (CD28+CD95+), regulatory T-cells (CD4+CD127-CD25high) and subpopulations Th and TCL co-expressed PD-1 and PD-L1. Multiple comparisons were assessed by ANOVA or Kruskal Wallis test by GraphPad Prism software. Results. In our study all 30 AA patients had an immunodominant TCR-Vβ clones among Th and/or TCL cells. We identified the most common clonotypes in comparison with healthy donors - Vβ1, Vβ2, Vβ3 among the Th cells and Vβ3, Vβ9, Vβ13.1 among the TCL cells. In ND group Vβ1 was highly expanded in 5 (38.5%), Vβ3 - in 7 (53.8%) pts among Th, and Vβ3 - in 3 (23.1%) and Vβ9 - in 4 (30.8%) out of 13 pts among TCL. In OR group Vβ2 expansion was in 4 (40%) and Vβ3 - in 5 (50%) pts among Th; Vβ3 in 6 (60%) and Vβ9 in 6 (60%) out of 10 pts among TCL. In NR group the most frequent was Vβ13.1 clone in TCL - in 3 (42.9%) out of 7 pts. In NR group in overall clonal expansion was less frequent than in ND and OR groups. We also analyzed the previously mentioned subpopulations of T-cells in patients with AA in three groups (ND, OR, NR) compared to healthy donors (table 1). We obtained significant differences in the count of naive Th and TCL cells, memory T-cells in all three groups of AA patients compared to donors: proportion of naive Th and TCL cells was significantly higher and proportion of memory Th cells was lower in the donor group than in AA pts. The percent of TCL effectors was higher in ND AA pts compare to donors. We also found that cell count of activated Th (CD4+CD25+) was higher in the group of refractory pts. In OR pts proportion of PD-1-positive Th was higher than in donors. In NR pts Th and TCL co-expressed with PD-L1 were lower compare to donors (table 1). Conclusions. In our study we found immunodominant clonotypes in different AA pts and depletion of the pool of naive T cells. Dynamic observation of changes in the most common clonotypes in AA pts during treatment will provide suitable therapy tactics (allogenic bone marrow transplantation or IST). Disclosures No relevant conflicts of interest to declare.

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Expansion of CD8+/perforin+ T-Cell Subset in Patients Predicts Response to Cyclosporin A Therapy in Patients with Erythroid Hypoplasia/Aplasia

Blood ◽

10.1182/blood.v118.21.1337.1337 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1337-1337

Author(s):

Hideaki Nitta ◽

Yuka Harada ◽

Hideo Hyodo ◽

Akiro Kimura ◽

Hironori Harada

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Cyclosporin A ◽

Aplastic Anemia ◽

Cell Subset ◽

T Cell Subsets ◽

Cell Subpopulation ◽

T Cell Subset ◽

Oligoclonal Expansion

Abstract Abstract 1337 Erythroid hypoplasia or aplasia is a hematological condition observed in including idiopathic pure red cell aplasia (PRCA), thymoma-associated PRCA and aplastic anemia. Myelodysplastic syndrome (MDS) with erythroid hypoplasia/aplasia in bone marrow is a rare type of MDS that was not included in existing classifications of MDS. Patients with erythroid hypoplasia/aplasia have common characteristics; transfusion dependencies, immunologic abnormalities and successful immunosuppressive therapies with cyclosporin A (CsA). Thus, we may regard erythroid hypoplasia/aplasia as one of hematological disease entities. However, pathogenic mechanisms of erythroid hypoplasia/aplasia have not been fully elucidated, although T-lymphocyte-mediated inhibition of erythropoiesis is suspected to be the most possible mechanism of the pathogenesis. Recently, we reported that oligoclonal expansion of CD8+/perforin+ T cells was observed in patients with thymoma-associated PRCA and the oligoclonality was exclusively detected in CD8+ T cells, but not CD4+ T cells. To clarify the pathogenetic role of the T-cells, we analyzed the T-cell subsets and therapeutic responses in patients with erythroid hypoplasia/aplasia in bone marrow. Among 253 patients with MDS diagnosed at Hiroshima University Hospital between 2000 and June 2011, 12 patients (4.7%) showed erythroid hypoplasia/aplasia. A total of 22 patients with erythroid hypoplasia/aplasia, including 8 MDS with erythroid hypoplasia/aplasia, 3 idiopathic PRCA, 3 thymoma-associated PRCA and 8 aplastic anemia, were enrolled in this study. All patients were treated with CsA and improvement in anemia in this study followed the International Working Group (IWG) 2006 criteria. For T-cell subset analysis, mononuclear cells (MNCs) were purified from bone marrow (BM) or peripheral blood (PB) of the patients. MNCs were stained with fluorescent (FITC, PE, PerCP or APC)-conjugated antibodies for CD8, perforin, CCR7, CD62L, CD27, CD28 and CD45RO, CD45RA and were subjected to flow cytometric analysis. As controls, 30 patients with MDS without erythroid hypoplasia/aplasia and 30 patients without BM abnormalities were also analyzed. Among 22 patients with erythroid hypoplasia/aplasia, 10 patients (4 MDS with erythroid hypoplasia/aplasia, 1 idiopathic PRCA, 3 thymoma-associated PRCA and 2 aplastic anemia) responded to CsA therapy within 2 to 8 weeks. The median blood hemoglobin concentration increased from 6.5 g/dL at the baseline to 9.3 g/dL with treatment, with a median increase of hemoglobin of 2.8 g/dL from the baseline. We attempted to compare the T-cell subsets between CsA-responders and non-responders. All of 3 thymoma-associated PRCA showed good response to CsA therapy, suggesting that the oligoclonal expansion of a CD8+/perforin+ T-cell subset may be associated with the responses to immunosuppressive therapy. Thus, we focused on a T-cell subpopulation expressing CD8+/perforin+. Intriguingly, the CD8+/perforin+ T cells were significantly increased in the CsA-responders (44.3 ± 9.6%, n=10) compared to the non-responders (19.0 ± 9.3%, n=12, P<0.0001), normal BM controls (16.9 ± 7.0%, n=30) and MDS without erythroid hypoplasia/aplasia (15.1 ± 7.0%, n=30). Among the CD8+/perforin+ T cells, CD27+/CD62L+/−/CCR7low/CD28low/CD45RA++/CD45RO+ population was prominent, which is consistent with an effector memory T (TEM) cell subset described by Decrion et al. Our study reveals that CD8+/perforin+ T cell subset is a large population in the patients with CsA-responsive erythroid hypoplasia/aplasia. It is suggested that CD8+/perforin+ T cell subset may have functions to reduce erythroid progenitors via immunological mechanisms. The mechanisms may be easily suppressed by immunosuppressive therapies. In conclusion, expansion of CD8+/perforin+ T cell subset predicts response to cyclosporin A therapy in patients with erythroid hypoplasia/aplasia. The disease entity of “erythroid hypoplasia/aplasia in bone marrow with expansion of CD8+/perforin+ T cell subset”, including MDS, PRCA with or without thymoma and aplastic anemia, may have common pathogenetic mechanisms. Disclosures: No relevant conflicts of interest to declare.

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Clonal Expansion of Bone Marrow CD8+ T Cells in Acute Myeloid Leukemia Patients at New Diagnosis and Post Chemotherapy

10.21203/rs.3.rs-50231/v1 ◽

2020 ◽

Author(s):

Zhongxin Feng ◽

Qin Fang ◽

Xingyi Kuang ◽

Xin Liu ◽

Ying Chen ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Clonal Expansion ◽

Cell Repertoire ◽

Healthy Donors ◽

Wide Range ◽

Tcr Repertoire ◽

Repertoire Diversity ◽

New Diagnosis

Abstract Background: CD8+ T cells are crucial adaptive immune effectors and express receptors (T cell receptors, TCRs) that specifically recognize and eradicate tumor cells. The diversity of the TCR repertoire is generated by specialized genetic diversification mechanisms, leading to an extremely variable TCR repertoire capable of recognizing a wide range of antigens. However, the variations in CD8+ TCR diversity and their clinical implications in AML patients remain unknown.Methods: CD8+ T cells in 10 healthy donors and 31 AML patients at diagnosis and after chemotherapy were enriched using the Dynabeads CD8 Positive Isolation Kit. Flow cytometry were used for PD-1 expression level analysis of CD8+ T cells and CD8+PD-1+ and CD8+PD-1- T cell sorting. TCRβ deep sequencing was performed to analysis the CD8+ T cells clonal expansion and TCR repertoire diversity.Results: Diminished TCR repertoire diversity and expansional T cell clones were noted in the bone marrow of AML patients. In relapsed patients, T cells were found to be more clonally expanded post chemotherapy when compared to new diagnosis. Moreover, more significantly expanded TCRβ clonotypes were noted in CD8+ PD-1+ T cells than in CD8+ PD-1- T cells regardless of the time point of examination. Conclusions: Our systematic T-cell repertoire analysis may help better characterize CD8+ T cells pre- and post-chemotherapy in AML, which may provide insights into therapeutic strategies in hematological malignancies.

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The impact of body mass index on adaptive immune cells in the human bone marrow

10.21203/rs.2.22852/v2 ◽

2020 ◽

Author(s):

Luca Pangrazzi ◽

Erin Naismith ◽

Carina Miggitsch ◽

Jose’ Antonio Carmona Arana ◽

Michael Keller ◽

...

Keyword(s):

Body Mass Index ◽

Bone Marrow ◽

T Cells ◽

Immune System ◽

T Cell ◽

Immune Cells ◽

Memory T Cells ◽

T Cell Subsets ◽

Adaptive Immune ◽

Adaptive Immune Cells

Abstract Background. Obesity has been associated with chronic inflammation and oxidative stress. Both conditions play a determinant role in the pathogenesis of age-related diseases, such as immunosenescence. Adipose tissue can modulate the function of the immune system with the secretion of molecules influencing the phenotype of immune cells. The importance of the bone marrow (BM) in the maintenance of antigen-experienced adaptive immune cells has been documented in mice. Recently, some groups have investigated the survival of effector/memory T cells in the human BM. Despite this, whether high body mass index (BMI) may affect immune cells in the BM and the production of molecules supporting the maintenance of these cells it is unknown.Methods. Using flow cytometry, the frequency and the phenotype of immune cell populations were measured in paired BM and PB samples obtained from persons with different BMI. Furthermore, the expression of BM cytokines was assessed. The influence of cytomegalovirus (CMV) on T cell subsets was additionally considered, dividing the donors into the CMV- and CMV+ groups.Results. Our study suggests that increased BMI may affect both the maintenance and the phenotype of adaptive immune cells in the BM. While the BM levels of IL-15 and IL-6, supporting the survival of highly differentiated T cells, and oxygen radicals increased in overweight persons, the production of IFNγ and TNF by CD8+ T cells was reduced. In addition, the frequency of B cells and CD4+ T cells positively correlated with BMI in the BM of CMV- persons. Finally, the frequency of several T cell subsets, and the expression of senescence/exhaustion markers within these subpopulations, were affected by BMI. In particular, the levels of bona fide memory T cells may be reduced in overweight persons.Conclusion. Our work suggests that, in addition to aging and CMV, obesity may represent an additional risk factor for immunosenescence in adaptive immune cells. Metabolic interventions may help in improving the fitness of the immune system in the elderly.

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Postvaccination graft dysfunction/aplastic anemia relapse with massive clonal expansion of autologous CD8+ lymphocytes

Blood Advances ◽

10.1182/bloodadvances.2019000853 ◽

2020 ◽

Vol 4 (7) ◽

pp. 1378-1382

Author(s):

Caitlin Ritz ◽

Wenzhao Meng ◽

Natasha L. Stanley ◽

Miren L. Baroja ◽

Chong Xu ◽

...

Keyword(s):

Bone Marrow ◽

T Cell ◽

T Lymphocytes ◽

Aplastic Anemia ◽

Clonal Expansion ◽

Graft Dysfunction ◽

Bone Marrow Aplasia ◽

Key Points

Key Points Acquired aplastic anemia is a T-cell–mediated autoimmune bone marrow aplasia, without a known etiologic trigger. Clonal expansion of CD8+ effector T lymphocytes can occur following vaccination and accompany graft dysfunction or aplastic anemia relapse.

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STAT3 mutations indicate the presence of subclinical T-cell clones in a subset of aplastic anemia and myelodysplastic syndrome patients

Blood ◽

10.1182/blood-2013-04-494930 ◽

2013 ◽

Vol 122 (14) ◽

pp. 2453-2459 ◽

Cited By ~ 69

Author(s):

Andres Jerez ◽

Michael J. Clemente ◽

Hideki Makishima ◽

Hanna Rajala ◽

Ines Gómez-Seguí ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Myelodysplastic Syndrome ◽

Aplastic Anemia ◽

Somatic Mutation ◽

Bone Marrow Failure ◽

Cell Clones ◽

Key Points ◽

Stat3 Mutations

Key PointsSTAT3+ T cells are found not only in detected concomitant LGL-BMFs, but in cases in which an LGL expansion was not suspected. Transformation via acquisition of a somatic mutation in T cells may be a mechanism of immune, mainly hypoplastic, bone marrow failure.

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A Longitudinal Analysis of the T-Cell Receptor Vβ Repertoire in Aplastic Anemia Patients at Initial Presentation, Remission, and Relapse.

Blood ◽

10.1182/blood.v106.11.2402.2402 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2402-2402

Author(s):

Yunfeng Cheng ◽

Yong Tang ◽

Spencer Green ◽

Keyvan Keyvanfar ◽

Tullia Bruno ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

T Cell ◽

Aplastic Anemia ◽

T Cell Receptor ◽

Immunosuppressive Treatment ◽

Cell Receptor ◽

Initial Presentation ◽

Cell Counts ◽

Therapeutic Decisions

Abstract Aplastic anemia is a bone-marrow-failure syndrome characterized by low blood-cell counts and a fatty bone marrow. In most cases, no obvious etiological factor can be identified, but clinical responses to immunosuppressive treatment (IST) strongly suggest an immune pathophysiology. Our previous study of T-cell receptor (TCR) Vβ (variable region of β-chain) repertoire usage by flow cytometry suggested that aplastic anemia results from antigen-specific lymphocyte attack on hematopoietic progenitors (Risitano et al. Lancet2004; 364:355). In the current work, 7 patients were investigated for Vβ pattern expression before first immunosuppresive treatment, at the remission, and again on relapse. The TCR Vβ repertoire was analyzed for CD4+ and CD8+ subsets, separately, by flow cytometry, using a monoclonal antibody set of 22 different Vβ chains. Most patients had very different patterns of Vβ usage from healthy individuals, and all but one showed expansion of at least one Vβ family before immunosuppressive treatment (Vβ family expansions were defined as 2 standard deviations (SD) from the means in controls). The median number of expanded Vβ families was 4 per patient among CD8CD28dim effector cells. At remission, almost all the initially expanded Vβ subfamilies decreased to less than 2SD of controls. At relapse, most of the expanded Vβ subsets were increased again. However, 5/7 patients showed new expanded Vβ subsets at recurrence of cytopenias, suggesting antigenic spread of new epitopes recognized by immune systems. Although no common pattern of specific expanded Vβ subsets could be identified among different patients, some Vβ subfamilies appeared to be more frequently involved (Vβ 5.1 and Vβ 5.2 were expanded in 4 of 7 patients both at initial presentation and relapse ). These data suggest that monitoring Vβ subsets in aplastic anemia, and potentially in other immune-mediated human diseases of a similar pathophysiology could be used to guide individual therapeutic decisions and in the development of new treatments.

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SAP (SH2D1A), the Immunomodulator Deficient in X-Linked Lymphoproliferative Syndrome (XLP), Is Profoundly Decreased in Aplastic Anemia: An Immunologic Link between Constitutional and Acquired Bone Marrow Failure.

Blood ◽

10.1182/blood.v108.11.1141.1141 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1141-1141

Author(s):

Elena E. Solomou ◽

Valeria Visconte ◽

Federica Gibellini ◽

Neal S. Young

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Aplastic Anemia ◽

T Cell Activation ◽

Cell Activation ◽

Bone Marrow Failure ◽

Protein Levels ◽

Ifn Γ ◽

Th1 Polarization

Abstract Ligation of the signaling lymphocyte activation molecule (SLAM), a member of the immunoglobulin superfamily expressed in T and B cells, results in T cell activation and Th1 cytokine production. SAP is a small cytoplasmic protein expressed in T- and NK cells that controls the activation signals mediated by SLAM. On T cell activation, SAP binds to Fyn kinase; Fyn is activated and phosphorylates tyrosine residues on SLAM; phosphorylation results in the formation of a complex that selectively down-regulates co-stimulatory signals in activated T cells, resulting in inhibition of IFN-γ production. Thus SAP acts as a natural suppressor of SLAM-mediated T cell activation, and, in the absence of SAP, T cells are constitutively activated and overproduce IFN-γ. Mutations in the SAP gene lead to abnormal T cell activation and enhanced Th1 cytokine production in mouse models and in humans: about half of patients with X-linked lympoproliferative disease (XLP) have functionally disabling SAP mutations. Acquired aplastic anemia (AA) is a bone marrow failure syndrome in which hematopoietic cell destruction is effected by cytotoxic T cells and type 1 cytokines. We have recently shown that T cells from patients with AA have increased protein levels of T-bet, resulting in IFN-γ overproduction (Solomou EE et al, Blood2006; 107:3983). IFN-γ inhibits hematopoietic stem cell proliferation and induces Fas-mediated apoptosis; stem cell depletion results in marrow hypoplasia and peripheral blood pancytopenia. We examined SAP expression as an explanation for aberrant T cell activation and extreme Th1 polarization. SAP protein expression on immunoblot was very low to absent in unstimulated T cells from 16 of 20 AA patients examined, as compared to normal levels of expression in equivalent numbers of healthy donors (p<0.001). No significant differences were detected in Fyn and SLAM protein levels between AA and controls. SAP mRNA levels were also significantly decreased in T cells from those AA patients with low SAP protein levels, as determined by RT-PCR. Peripheral blood DNA samples from 18 patients with AA were analyzed for SAP mutations: three novel intronic mutations, not present in controls, were identified among 7 unrelated patients: one mutation was in the promoter region of SAP (position 106, C to T; 3 patients), and two mutations in the intron-exon junction between exons 1 and 2 (position 38975, C toT; 3 patients) and 3 and 4 (position 62771, C to A; 1 patient). IFN-γ, as measured by ELISA, in three patients with undetectable SAP protein levels was significantly increased compared to healthy controls (n=5, p<0.001). Increased IFN-γ levels and Th1 polarization in AA can in part be explained by functional SAP deficiency. SAP-deficient T cells in AA would be unable to block co-stimulatory signals, leading to an activated T cell phenotype and ultimately hematopoietic cell destruction and bone marrow failure. The SAP-deficient phenotype in T cells from patients with aplastic anemia may be secondary to subtle genetic alteration in the gene’s regulation (abnormal promoter binding sites or epigenetic modulation due to mutations in introns) or as yet unidentified aberrant upstream pathways (Ets-1 and Ets-2, the transcription factors that regulate SAP expression).

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Study on Mechanism of Human Marrow Mesenchymal Stem Cell in Treating Patients with Aplastic Anemia.

Blood ◽

10.1182/blood.v110.11.4099.4099 ◽

2007 ◽

Vol 110 (11) ◽

pp. 4099-4099

Author(s):

Zhenhua Qiao ◽

Xiujuan Zhao

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

T Cells ◽

Aplastic Anemia ◽

Hematopoietic Cell ◽

Control Group ◽

Rt Pcr ◽

Tnf Α ◽

Ifn Γ ◽

Tgf Β1

Abstract Objective: To explore mechanism of human marrow mesenchymal stem cells (MSCs) in treating patients with aplastic anemia(AA). Methods: MSCs in patients with aplastic anemia(AA) and the control group were separated with Percoll(1.073g/m L) and cultured in low glucose DMEM. Then, observed their morphologies,checked their molecule surface antigen by flow cytometry and examined the process of adipogenic differention. The mononuclear cells (MNC)of marrow in patients with AA were enriched based 1.077g/L density centrifuge and cultured in the 1640 medium. (1)MSC in control group and MNC in AA group were co-cultured with or without cytokines. The function of supporting hematopoiesis for MSC was to be observed in single confluence layer after plating by counting the total cells and the clones in every well every week. Then analyzed the dynamics of proliferation. T cells were harvested by using nylon column. MSC in control group and T cells in AA group were co-cultured. The proliferation of T cell was measured by MTT method. The CD25,CD69,CD4,CD8,Annexin-V expression rates of CD3+T cells were analyzed by flow cytometry .The gene and protein of IL-2, IL-4,IL-10,TNF-α,IFN-γ,TGF-β1 were examined by RT-PCR and ELISA respectively. MSC treated to the model of AA, by the examination of peripheral hemogram, bone marrow biopsy, pathological section of spleen. Results: There was no significant difference between control group MSC and AA-MSC in morphologies but adipogenic differentiation in AA patients is earlier than controls. The clones of CFU-GM in group(MSC)(78.46±3.58)/2×105 cells, after 14 days cultured was significantly higher than(9.21±4.32)/2×105 cells in group(CK + DMEM medium), while lower than (99.32±4.34)/2×105 cells in group(MSC+CK). (1)the Treg cells (TCD4+CD25+) in AA group (2.01±1.21)/ 2×105 was significantly lower than (4.43±1.67)/2×105 cells in control group, while(5.43±2.31) / 2×105 in group (MSC+AAT) was no more than (4.43±1.67)/2×105 cells in control group. (2) MSCs significantly inhibited T cell proliferation (P< 0. O5)by MTT. (3) RT-PCR and ELISA analysis showed that MSCs induced the expression of IL-4, IL-10, TGF-β1 and decreased significantly the expression of IL-2, TNF-α, IFN -γ in T cells of AA. the model of AA treated by MSCs showed improvements in 3 blood components greatly(p<0.05), Bone marrow proliferated and restored to the normal level, hematopoietic cell increased obviously (hematopoietic cell capacity was more than 40%), and atrophied spleen restore to normality. Conclusions: morphologies of AA’MSC had no evident different with the control but was more easy adipogenic differention. aplastic anemia belongs to autoimmune diseases in which T cells effect organ-specific destruction. The fundamental mechanism of MSC in treating AA should be potential to promote hematopoietic cell proliferation by adjusting immunity.

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Pentostatin Facilitates Fully MHC-Disparate Murine Mini-Transplantation.

Blood ◽

10.1182/blood.v114.22.3539.3539 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3539-3539

Author(s):

Jacopo Mariotti ◽

Kaitlyn Ryan ◽

Paul Massey ◽

Nicole Buxhoeveden ◽

Jason Foley ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Immune Suppression ◽

Graft Rejection ◽

Mixed Chimerism ◽

Post Transplant

Abstract Abstract 3539 Poster Board III-476 Pentostatin has been utilized clinically in combination with irradiation for host conditioning prior to reduced-intensity allogeneic hematopoietic stem cell transplantation (allo-HSCT); however, murine models utilizing pentostatin to facilitate engraftment across fully MHC-disparate barriers have not been developed. To address this deficit in murine modeling, we first compared the immunosuppressive and immunodepleting effects of pentostatin (P) plus cyclophosphamide (C) to a regimen of fludarabine (F) plus (C) that we previously described. Cohorts of mice (n=5-10) received a three-day regimen consisting of P alone (1 mg/kg/d), F alone (100 mg/kg/d), C alone (50 mg/kg/d), or combination PC or FC. Combination PC or FC were each more effective at depleting and suppressing splenic T cells than either agent alone (depletion was quantified by flow cytometry; suppression was quantified by cytokine secretion after co-stimulation). The PC and FC regimens were similar in terms of yielding only modest myeloid suppression. However, the PC regimen was more potent in terms of depleting host CD4+ T cells (p<0.01) and CD8+ T cells (p<0.01), and suppressing their function (cytokine values are pg/ml/0.5×106 cells/ml; all comparisons p<0.05) with respect to capacity to secrete IFN-g (13±5 vs. 48±12), IL-2 (59±44 vs. 258±32), IL-4 (34±10 vs. 104±12), and IL-10 (15±3 vs. 34±5). Next, we evaluated whether T cells harvested from PC-treated and FC-treated hosts were also differentially immune suppressed in terms of capacity to mediate an alloreactive host-versus-graft rejection response (HVGR) in vivo when transferred to a secondary host. BALB/c hosts were lethally irradiated (1050 cGy; day -2), reconstituted with host-type T cells from PC- or FC-treated recipients (day -1; 0.1 × 106 T cells transferred), and challenged with fully allogeneic transplant (B6 donor bone marrow, 10 × 106 cells; day 0). In vivo HVGR was quantified on day 7 post-BMT by cytokine capture flow cytometry: absolute number of host CD4+ T cells secreting IFN-g in an allospecific manner was ([x 106/spleen]) 0.02 ± 0.008 in recipients of PC-treated T cells and 1.55 ± 0.39 in recipients of FC-treated cells (p<0.001). Similar results were obtained for allospecific host CD8+ T cells (p<0.001). Our second objective was to characterize the host immune barrier for engraftment after PC treatment. BALB/c mice were treated for 3 days with PC and transplanted with TCD B6 bone marrow. Surprisingly, such PC-treated recipients developed alloreactive T cells in vivo and ultimately rejected the graft. Because the PC-treated hosts were heavily immune depleted at the time of transplantation, we reasoned that failure to engraft might be due to host immune T cell reconstitution after PC therapy. In an experiment performed to characterize the duration of PC-induced immune depletion and suppression, we found that although immune depletion was prolonged, immune suppression was relatively transient. To develop a more immune suppressive regimen, we extended the C therapy to 14 days (50 mg/Kg) and provided a longer interval of pentostatin therapy (administered on days 1, 4, 8, and 12). This 14-day PC regimen yielded CD4+ and CD8+ T cell depletion similar to recipients of a lethal dose of TBI, more durable immune depletion, but again failed to achieve durable immune suppression, therefore resulting in HVGR and ultimate graft rejection. Finally, through intensification of C therapy (to 100 mg/Kg for 14 days), we were identified a PC regimen that was both highly immune depleting and achieved prolonged immune suppression, as defined by host inability to recover T cell IFN-g secretion for a full 14-day period after completion of PC therapy. Finally, our third objective was to determine with this optimized PC regimen might permit the engraftment of MHC disparate, TCD murine allografts. Indeed, using a BALB/c-into-B6 model, we found that mixed chimerism was achieved by day 30 and remained relatively stable through day 90 post-transplant (percent donor chimerism at days 30, 60, and 90 post-transplant were 28 ± 8, 23 ± 9, and 21 ± 7 percent, respectively). At day 90, mixed chimerism in myeloid, T, and B cell subsets was observed in the blood, spleen, and bone marrow compartments. Pentostatin therefore synergizes with cyclophosphamide to deplete, suppress, and limit immune reconstitution of host T cells, thereby allowing engraftment of T cell-depleted allografts across MHC barriers. Disclosures: No relevant conflicts of interest to declare.

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Flow Cytometry Primary 10 Colours Panel for Chronic Lympho Proliferative Diseases Diagnosis

Blood ◽

10.1182/blood.v118.21.5190.5190 ◽

2011 ◽

Vol 118 (21) ◽

pp. 5190-5190

Author(s):

Jonathan Brauner ◽

Ingrid Beukinga ◽

Zoulikha Amraoui ◽

Zaina Kassengera ◽

Michel Toungouz ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

T Cells ◽

T Cell ◽

B Cells ◽

B Lymphocytes ◽

Plasma Cells ◽

Cell Lymphoma ◽

Cd10 Expression ◽

Complete Characterisation

Abstract Abstract 5190 Objectives: Definition of the primary antibodies panel for 10 colours flow cytometry able to describe normal and clonal T, B lymphocytes and plamocytes in blood and bone marrow. Once clonalities are detected, the complete characterisation of Chronic Lymphoproliferative Diseases (CLPD) is supported by secondary panels chosen based on the results of CD5/CD10 expression for clonal B lymphocytes, CD27/CD38 for plasmatocytes and CD3/CD27 for clonal T cells. Materials and Methods: Blood and bone marrow of patients (N=50) with CLPD (mainly B-CLL). Samples are enumerated by haematology analyzer DxH 800 then 106 cells are washed three times, stained with the antibodies combination and red blood cells lysed with Versalyse (TM. Beckman Coulter). The samples were analysed on a 10 colours Navios flow cytometer (Beckman Coulter Fullerton, CA). The staining panel consists of 14 antibodies (CD45, CD8, CD4, CD5, CD3, CD19, CD38, λ, κ, CD23, CD5, CD10, CD14, CD27) conjugated with 10 different fluorochromes. The fixed gating strategy allows linking Navios analysis software to the middleware Remisol which drives the choice of the secondary panel. In some cases a third tube is performed for Ki67 or Zap-70 intra-cytoplasmic staining. Results: Monocytes are removed on the basis of their CD14/CD4 expression. B lymphocytes are CD19 positive. Normal naïve/memory B cells, hematogones and plasma cells are defined by their CD27, CD10 and CD38 expression. Eventual monoclonality is sought by analysis of the distribution of Kappa and Lambda light chains. A first classification of B cell lymphoma is achieved with the CD5 and CD10 expression of the clone (CD5+/CD10−: B-CLL MCL and few MZL, CD5−/CD10−: MZL and related, CD5−/CD10+ DLBCL and FL). Analysis of CD27, CD20 and CD23 expression allows discriminating between CD5+/CD10- lymphomas. All the 50 samples were correctly detected as CLPD and the automated Remisol choice of the second panel fit to the final diagnosis of all the cases of this small series. T lymphocytes are defined by their CD3 and CD5 expression. The analysis of CD4/CD8 balance and CD27/CD5 distribution are first line test when T cell clonality is suspected. There is a special gating to detect CD3-CD4+ T cell lymphoma and double negativity of CD4 and CD8 is a surrogate marker for gamma/delta T cells. NK cells are mentioned as not-T not-B lymphocytes, without specific staining. Conclusion/Discussion:This 10 colours 14 antibodies panel allows describing in one tube normal T and B cells, hematogones, memory and naives B cells plasma cells and detects T and B clonalities. This panel follows a similar logic than the Euroflow LST tube but with 10 colours and with Beckman Coulter's technology and antibodies. Moreover, this combination helps discriminating rapidly the CD5+/CD10- lymphomas while the complete characterisation of CD5 negative lymphomas only require less than 6 antibodies second tube. This is a paperless (all the process is driven and controlled by Remisol), fast and inexpensive diagnostic approach (always less than 20 antibodies required). Disclosures: Pradier: Beckman Coulter: Consultancy, Membership on an entity's Board of Directors or advisory committees.

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