Antibodies from Donor B Cells Are Not Required for Initiating but Required for Persisting Scleroderma in Chronic Gvhd

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3817-3817
Author(s):  
Hua Jin ◽  
Xiong Ni ◽  
Ruishu Deng ◽  
James Young ◽  
Heather F Johnston ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd4 T Cells ◽  
Conflicts Of Interest ◽  
Chronic Gvhd ◽  
Cell Interaction ◽  
Spleen Cells ◽  
Littermate Control ◽  
Inflammatory Status

Abstract We recently reported that in a chronic graft versus host disease (GVHD) model of DBA/2 donor to MHC-matched BALB/c recipient, donor CD4+ T and B cell interaction resulted in not only hyperglobulinemia and glomerulonephritis but also scleroderma (J. Immunol. 2012). It is well known that glomerulonephritis is caused by immune complex deposition. However, the role of antibodies from donor B cells in the pathogenesis of scleroderma remains unclear. To address this question, we generated DBA/2 mice whose B cells have APC function but cannot secrete antibodies by backcrossing IgHµg1 mice from Dr. Rajewsky’s lab (JEM 2007). We observed that, while transplanting T-cell-depleted bone marrow (TCD-BM) and spleen cells from littermate control mice induced proteinuria and scleroderma, transplanting BM and spleen cells from IgHµg1 DBA/2 mice induced no proteinuria, but the recipients developed scleroderma ~35 days after HCT. Interestingly, the scleroderma gradually recovered ~55 days after HCT. 40 days after HCT, scleroderma recipients transplanted with WT spleen cells (Rec-WT) or recipients transplanted with IgHµg1 spleen cells (Rec-IgHµg1) both had high percentage (~12%) of IFN-g+ or IL-17+ CD4+ T cells in the peripheral lymph node (PLN) and skin tissues, as compared to that (~3%) of GVHD-free recipients given TCD-BM alone (Rec-TCD). While Rec-WT had severe reduction of CD4+CD8+ thymocytes, the Rec-IgHµg1 had no reduction of the thymocytes, as compared to that of Rec-TCD. By day 60 after HCT, the Rec-WT with ongoing scleroderma still had ~10% IFN-g+ or IL-17+ CD4+ T cells in the PLN and skin tissues; in contrast, although the Rec-IgHµg1 with reversal of scleroderma still had >10% IFN-g+or IL-17+ CD4+ T cells in the PLN, those cells in the skin had reduced to <2%. This reduction was associated with DC upregulation of B7H1 and T cell upregulation of PD-1. These results suggest that antibodies from B cells are required for maintaining inflammatory status of tissue DCs and persistence of scleroderma in chronic GVHD. (This work was supported by NIH R01 AI066008). Disclosures No relevant conflicts of interest to declare.

Donor CD4+ T Cells That Possess Both Allo- and Autoreactivity in Transplants Mediate Chronic Graft Versus Host Disease.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3555-3555
Author(s):  
Dongchang Zhao ◽  
Yu-Hong Chen ◽  
James Young ◽  
Elizabeth Shen ◽  
Tangsheng Yi ◽  
...  
Keyword(s):  
T Cells ◽  
Graft Versus Host Disease ◽  
Cd4 T Cells ◽  
Conflicts Of Interest ◽  
Chronic Gvhd ◽  
Spleen Cells ◽  
Autoreactive T Cells ◽  
Host Disease ◽  
Graft Versus Host

Abstract Abstract 3555 Poster Board III-492 Chronic graft versus host disease (GVHD) is considered an autoimmune-like disease mediated by donor CD4+ T cells, but the role and origin of the autoreactive T cells remain controversial. Here, we report that, in a chronic GVHD model of MHC-matched DBA/2 (H-2d) donor to BALB/c (H-2d) host, donor spleen cells induced autoimmune-like chronic GVHD in thymectomized allogeneic BALB/c but not in syngeneic DBA/2 recipients. The spleen cells from the former but not the latter recipients induced autoimmune-like disease in the secondary DBA/2 recipients, indicating that autoreactive donor CD4+ T cells from transplants are expanded and contribute to chronic GVHD pathogenesis. In addition, we found that both auto- and alloreactive donor CD4+ T cells generated from primary chronic GVHD recipients via serial in vivo and in vitro expansion proliferated to donor and host DC stimulation and both induced autoimmune-like disease in syngeneic and allogeneic recipients. Furthermore, the clonal expansion and TCR spreading of the autoreactive T cells in chronic GVHD recipients were following the alloreactive T cells, as revealed by TCR-spectrum typing and skewing of TCR-CDR3 length; No dual TCR was expressed by the donor-type T cells with both allo- and autoreactivity; and the autoreactive hybridoma T clones proliferated to stimulation by both syngeneic and allogeneic DCs. Taken together, these results demonstrate that donor CD4+ T cells that possess both allo- and autoreactivity in transplants are expanded in recipients and contribute to chronic GVHD pathogenesis, and the allo- and autoreactivity of the donor T cells can be mediated by a single TCR. Disclosures: No relevant conflicts of interest to declare.

JQ 1, a Selective Bromodomain Inhibitor, Decreased the Expression of the Tolerogenic Molecule PDL1 in Antigen-Presenting Cells (APCs) and Restores the Responsiveness of Anergic CD4+ T Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2749-2749 ◽  
Author(s):  
Hongwei Wang ◽  
Fengdong Cheng ◽  
Limin Xing ◽  
Xiaohong Zhao ◽  
Alejandro Villagra ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Inflammatory Cytokine ◽  
Conflicts Of Interest ◽  
Specific Inhibitor ◽  
Inflammatory Status ◽  
Bet Inhibitors ◽  
Cognate Antigen ◽  
Antigen Presenting

Abstract Bromodomain and extraterminal (BET) is a protein domain that recognizes acetylated lysine residues such as those on the N-terminal tails of histones. This recognition is often a prerequisite for protein-histone association, chromatin remodeling and gene transcription. The role of BET proteins in regulating the response of inflammatory cytokine genes through translation of histone marks is poorly understood. Given that the inflammatory status of the APC is critical in determining T-cell activation versus T-cell tolerance and that epigenetic modifications of specific genes in the APC play a key role in this process, we recently determined the functional consequences of inhibiting BET in APCs. First, we evaluated the effects of JQ 1, a selective small-molecule BET bromodomain inhibitor on APC’s function and its regulation of antigen-specific CD4+ T-cells response. In vitro treatment of peritoneal elicited macrophages (PEM) or bone marrow derived dendritic cells (DCs) with increasing concentrations of JQ 1 resulted in decreased expression and protein production of the anti-inflammatory cytokine IL-10 and IL-6 in response to LPS stimulation. At the concentration used, JQ 1 did not affect the viability of treated APCs. Second, analysis of the expression of MHC class molecules and co-stimulatory molecules revealed a decreased expression of the tolerogenic PDL1 molecule in JQ 1- treated APCs as compared to untreated APCs. Third, we evaluated the ability of JQ 1 treated APCs to present cognate antigen to naïve or tolerant antigen-specific CD4+ T-cells. We found that treatment of either PEM or DC with JQ 1 enhanced their antigen-presenting capabilities leading to effective priming of naïve CD4+ T-cells confirmed by their increased production of IL-2 and IFN-gamma in response to cognate antigen. More importantly, JQ 1- treated APCs were able to restore the responsiveness of tolerant CD4+ T-cells isolated from lymphoma bearing hosts. Taken together, we have found that APCs treated with the Bromodomain specific inhibitor JQ 1 are more inflammatory, display lower expression of the immunosuppressive molecule PDL1 and more importantly, are capable of restoring the responsiveness of tolerant T-cells. Our studies therefore have unveiled a previously unknown immunological effect of BET inhibitors and have broadened their clinical scope as promising adjuvants in cancer immunotherapy. Disclosures No relevant conflicts of interest to declare.

HIV-Infected T Cells Induce Granzyme B-Secreting Regulatory B Cells in An Interleukin 21-Dependent Fashion,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3222-3222
Author(s):  
Christof Kaltenmeier ◽  
Karen Dahlke ◽  
Ali Gawanbacht ◽  
Thamara Beyer ◽  
Stefanie Hofmann ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Acute Phase ◽  
Cd4 T Cells ◽  
Conflicts Of Interest ◽  
Granzyme B ◽  
T Cell Proliferation ◽  
Hiv 1

Abstract Abstract 3222 We and others have recently provided evidence that a series of lymphocyte subsets including, plasmacytoid dendritic cells, B cells and regulatory T cells are able to secrete the cytotoxic serine protease granzyme B (GrB) into the extracellular compartment, where it contributes to the suppression of T cell proliferation by a so far undefined GrB-dependent mechanism. For B cells, we found that viral antigens in the context of the acute phase cytokine interleukin (IL-) 21 can potently induce GrB. Here, we demonstrate that infection of CD4+ T cells with HIV-1 (NL4-3), but not mock infection, induces strong expression of IL-21 on both mRNA and protein levels in CD4+ T cells. Moreover, we found that HIV-infected CD4+ T cells are able to induce high levels of GrB in co-cultured B cells and that inhibition of IL-21 with specific antibodies abrogates T cell-mediated GrB induction in B cells. In support of these data, serum levels of both IL-21 and GrB are significantly higher in patients acutely infected with HIV as compared to healthy control subjects. Surprisingly, co-culture of CD4+ T cells with B cells during HIV-1 infection strongly suppressed both, proliferation of T cells as well as virus replication as indicated by significantly reduced p24 levels in culture supernatants. Notably, this effect was enhanced by external stimulation of B cells with IL-21, and was reduced by inhibition of GrB using specific GrB inhibitors. To further explore the underlying mechanisms of our findings, we performed confocal microscopy of T cell-B cell co-cultures and demonstrated that GrB-secreting B cells directly interact with CD4+ T cells, thereby transferring active GrB to them. Moreover, we found that GrB+ B cells decreased CD4+ T cell expression of the T cell receptor-zeta chain, a known GrB target, which is required for T cell proliferation, and known to be suppressed in HIV patients. In summary, we provide evidence that HIV induces the acute phase cytokine IL-21 in infected CD4+ T cells, thereby indirectly triggering the expression of GrB by B cells. GrB-secreting B cells may play a so far unappreciated role in decelerating the expansion of HIV, particularly in the early phase of acutely infected patients. Our study reveals a novel pathogenetic mechanism in HIV infection with potential relevance for the development of novel immunotherapeutic approaches. Disclosures: No relevant conflicts of interest to declare.

Costimulation Through GITR Increases Follicular Helper T Cell Formation and Leads To Control Of A Chronic Viral Infection

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3496-3496
Author(s):  
Fernanda M Pascutti ◽  
Tomasz Poplonski ◽  
René A.W. Van Lier ◽  
Claudia Brandao ◽  
Martijn A. Nolte
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd4 T Cells ◽  
Viral Infections ◽  
Conflicts Of Interest ◽  
Cell Formation ◽  
Absolute Number ◽  
Costimulatory Receptor ◽  
Follicular Helper

Abstract The glucocorticoid-induced TNF receptor family-related protein (GITR) is an important costimulatory receptor on T cells. We have previously shown that enhanced costimulation through GITR increases the formation of both effector and regulatory CD4+ T cells. Here we explored whether it could also affect humoral immunity and T cell help to B cells. Although development of mature B cells was not affected in GITRL transgenic (tg) mice, we found that the number of follicular helper T cells (CXCR5+ PD1+ CD4+ T cells, Tfh) was significantly increased, including the absolute number of Tfh-B cell conjugates, as revealed by ImageStream analysis. Tfh from GITRL tg mice had normal expression levels of ICOS, SLAM and CD44 and slightly lower levels of CD62L and CCR7 compared to wild-type (WT) littermates. Interestingly, Tfh from GITRL tg mice produced more IFN-g and IL-10, which was accompanied by a biased antibody repertoire (decreased IgG3 and increased IgA, IgG2a and IgG2b). Since Tfh have been implicated in the late control of viral replication, we infected WT and GITRL tg mice with LCMV Clone 13. Surprisingly, at day 30 after infection, we could not detect viral genome in spleen and liver from GITRL tg mice, while WT mice were still infected. Also, PD-1 expression was strongly decreased on virus-specific CD8+ T cells, which correlated with faster viral clearance. All in all, these results indicate that GITR-mediated costimulation enhances the control of chronic viral infections, by boosting and modulating Tfh cell responses. Disclosures: No relevant conflicts of interest to declare.

Administration Of Anti-CD20 Mab Is Highly Effective In Preventing But Ineffective In Treating Chronic GVHD While Preserving A Strong GVL Effect

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2010-2010
Author(s):  
Heather F Johnston ◽  
Ya-jing Xu ◽  
Xiong Ni ◽  
Tao Wu ◽  
Jeremy Racine ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Hair Loss ◽  
Cd4 T Cells ◽  
Chronic Gvhd ◽  
Cd8 T Cell ◽  
Effective Prevention ◽  
Anti Cd20 ◽  
The Impact

Abstract Donor T cell-mediated graft versus leukemia/lymphoma (GVL) effect plays a critical role in preventing tumor relapse in leukemia/lymphoma patients treated with allogeneic hematopoietic cell transplantation (HCT). However, these same donor T cells also induce acute and chronic graft versus host disease (GVHD), which remains a major obstacle for allogeneic HCT as a curative therapy for hematological malignancies. Chronic GVHD is a systemic lupus- and scleroderma-like autoimmune syndrome. We and others reported that donor B cells play important roles in augmenting pathogenesis of chronic GVHD in mouse models and humans. Rituxan (an anti-CD20 mAb) has been used in the clinic for the treatment of ongoing chronic GVHD, but the effect is variable and minimum in some reports, and the mechanisms for this ineffectiveness remains unclear. In the current studies, we evaluated the effect of in vivo administration of a depleting anti-CD20 mAb in preventing and treating autoimmune-like chronic GVHD as well as the impact on GVL effect. With the mouse chronic GVHD model of DBA/2 donor to MHC-matched BALB/c recipient established in our lab (Blood, 2006, J. Immunol 2012), we found that one intravenous injection of anti-CD20 (50mg/kg) immediately after HCT effectively prevented induction of autoimmune-like chronic GVHD. While all (12/12) recipients treated with control IgG developed chronic GVHD with proteinuria and hair-loss and died by 30 days, none (0/12) of the anti-CD20-treated recipients developed proteinuria or hair-loss and all survived for more than 50 days after HCT without signs of chronic GVHD. In addition, the anti-CD20-treated recipients eliminated BCL1 leukemia/lymphoma cells without signs of chronic GVHD. The preventative anti-CD20 treatment had little impact on donor CD8+ T cell activation and expansion in the periphery and allowed for the strong CD8+ T cell-mediated GVL effect. The effective prevention of chronic GVHD by anti-CD20 was associated with significant changes in donor B and CD4+ T cells as well as associated with protection of host thymus. Preventive anti-CD20 treatment depleted IL-6-producing donor B cells and increased IL-10-producing B cells. In addition, the treatment also significantly reduced donor CD4+ T cell expansion, the percentage of IFN-g-producing CD4+ T as well as CD4+ T cells expressing CD8αα, the latter of which has recently been reported to represent over-activated pathogenic CD4+ T cells, such that the host thymus was protected from donor T-cell-mediated damage. Anti-CD20 or control IgG treatment of recipients with ongoing chronic GVHD 15-20 days after HCT did not show any difference in disease progress, and all (8/8) in each group died within 30 days after HCT. The ineffectiveness of anti-CD20 therapy was associated with little reduction of CD19+ B or CD4+ T cells, as the majority of CD19+ B cells became CD20- in the recipients with ongoing chronic GVHD. These results indication that anti-CD20 can effectively prevent induction of autoimmune-like chronic GVHD while preserving the GVL effect, but anti-CD20 is ineffective in treating ongoing chronic GVHD. (This study is supported by the Nesvig Lymphoma Foundation). Disclosures: Chan: Genentech Inc.: Employment.

scholarly journals Macrophage-T Cell Interaction Is Essential for the Induction of p75 Interleukin 2 (IL-2) Receptor and IL-2 Responsiveness in Human CD4+T Cells

1991 ◽  
Vol 82 (3) ◽  
pp. 257-261 ◽  
Author(s):  
Yoshihiko Nakamura ◽  
Takashi Nishimura ◽  
Yutaka Tokuda ◽  
Nobumasa Kobayashi ◽  
Katsuto Watanabe ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Interleukin 2 ◽  
Cell Interaction

scholarly journals The role of H-2-linked genes in helper T cell function. VII. Expression of I region and immune response genes by B cells in bystander help assays.

1980 ◽  
Vol 152 (5) ◽  
pp. 1274-1288 ◽  
Author(s):  
P Marrack ◽  
J W Kappler
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Function ◽  
High Responder ◽  
Helper T Cells ◽  
Spleen Cells ◽  
Region Gene ◽  
Immunoglobulin Receptor

The mode of action by bystander helper T cells was investigated by priming (responder X nonresponder) (B6A)F1 T cells with poly-L-(Tyr, Glu)-poly-D,L-Ala--poly-L-Lys [(TG)-A--L] and titrating the ability of these cells to stimulate an anti-sheep red blood cell (SRBC) response of parental B cells and macrophages in the presence of (TG)-A--L. Under limiting T cell conditions, and in the presence of (TG)-A--L, (TG)-A--L-responsive T cells were able to drive anti-SRBC responses of high-responder C57BL/10.SgSn (B10) B cells and macrophages (M0), but not of low-responder (B10.A) B cells and M0. Surprisingly, the (TG)-A--L-driven anti-SRBC response of B10.A B cells was not restored by addition of high-responder acessory cells, in the form of (B6A)F1 peritoneal or irradiated T cell-depleted spleen cells, or in the form of B10 nonirradiated T cell-depleted spleen cells. These results suggested that (TG)-A--L-specific Ir genes expressed by B cells controlled the ability of these cells to be induced to respond to SRBC by (TG)-A--L-responding T cells, implying that direct contact between the SRBC-binding B cell precursor and the (TG)-A--L-responsive helper T cells was required. Analogous results were obtained for keyhold limpet hemocyanin (KLH)-driven bystander help using KLH-primed F1 T cells restricted to interact with cells on only one of the parental haplotypes by maturing them in parental bone marrow chimeras. It was hypothesized that bystander help was mediated by nonspecific uptake of antigen [(TG)-A--L or KLH] by SRBC-specific b cells and subsequent display of the antigen on the B cell surface in association with Ir of I-region gene products, in a fashion similar to the M0, where it was then recognized by helper T cells. Such an explanation was supported by the observation that high concentrations of antigen were required to elicit bystander help. This hypothesis raises the possibility of B cell processing of antigen bound to its immunoglobulin receptor and subsequent presentation of antigen to helper T cells.

scholarly journals Dual T cell– and B cell–intrinsic deficiency in humans with biallelic RLTPR mutations

2016 ◽  
Vol 213 (11) ◽  
pp. 2413-2435 ◽  
Author(s):  
Yi Wang ◽  
Cindy S. Ma ◽  
Yun Ling ◽  
Aziz Bousfiha ◽  
Yildiz Camcioglu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Ex Vivo ◽  
Cell Phenotype ◽  
Loss Of Function ◽  
Inborn Errors

Combined immunodeficiency (CID) refers to inborn errors of human T cells that also affect B cells because of the T cell deficit or an additional B cell–intrinsic deficit. In this study, we report six patients from three unrelated families with biallelic loss-of-function mutations in RLTPR, the mouse orthologue of which is essential for CD28 signaling. The patients have cutaneous and pulmonary allergy, as well as a variety of bacterial and fungal infectious diseases, including invasive tuberculosis and mucocutaneous candidiasis. Proportions of circulating regulatory T cells and memory CD4+ T cells are reduced. Their CD4+ T cells do not respond to CD28 stimulation. Their CD4+ T cells exhibit a "Th2" cell bias ex vivo and when cultured in vitro, contrasting with the paucity of "Th1," "Th17," and T follicular helper cells. The patients also display few memory B cells and poor antibody responses. This B cell phenotype does not result solely from the T cell deficiency, as the patients’ B cells fail to activate NF-κB upon B cell receptor (BCR) stimulation. Human RLTPR deficiency is a CID affecting at least the CD28-responsive pathway in T cells and the BCR-responsive pathway in B cells.

Vaccine-elicited CD4 T cells prevent the deletion of antiviral B cells in chronic infection

2021 ◽  
Vol 118 (46) ◽  
pp. e2108157118
Author(s):  
Kerstin Narr ◽  
Yusuf I. Ertuna ◽  
Benedict Fallet ◽  
Karen Cornille ◽  
Mirela Dimitrova ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Memory B Cells ◽  
Type I ◽  
Clonal Deletion ◽  
Cell Immunity ◽  
B Cell Immunity

Chronic viral infections subvert protective B cell immunity. An early type I interferon (IFN-I)–driven bias to short-lived plasmablast differentiation leads to clonal deletion, so-called “decimation,” of antiviral memory B cells. Therefore, prophylactic countermeasures against decimation remain an unmet need. We show that vaccination-induced CD4 T cells prevented the decimation of naïve and memory B cells in chronically lymphocytic choriomeningitis virus (LCMV)-infected mice. Although these B cell responses were largely T independent when IFN-I was blocked, preexisting T help assured their sustainability under conditions of IFN-I–driven inflammation by instructing a germinal center B cell transcriptional program. Prevention of decimation depended on T cell–intrinsic Bcl6 and Tfh progeny formation. Antigen presentation by B cells, interactions with antigen-specific T helper cells, and costimulation by CD40 and ICOS were also required. Importantly, B cell–mediated virus control averted Th1-driven immunopathology in LCMV-challenged animals with preexisting CD4 T cell immunity. Our findings show that vaccination-induced Tfh cells represent a cornerstone of effective B cell immunity to chronic virus challenge, pointing the way toward more effective B cell–based vaccination against persistent viral diseases.

A Detailed Phenotypic Analysis Using Six Color Flow Cytometry of Lymphocyte Subsets Mobilized with AMD3100 Compared to G-CSF.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 408-408 ◽  
Author(s):  
Yoshiyuki Takahashi ◽  
S. Chakrabarti ◽  
R. Sriniivasan ◽  
A. Lundqvist ◽  
E.J. Read ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Lymphocyte Subsets ◽  
Phenotypic Analysis ◽  
Color Flow ◽  
Cd34 Cells

Abstract AMD3100 (AMD) is a bicyclam compound that rapidly mobilizes hematopoietic progenitor cells into circulation by inhibiting stromal cell derived factor-1 binding to its cognate receptor CXCR4 present on CD34+ cells. Preliminary data in healthy donors and cancer patients show large numbers of CD34+ cells are mobilized following a single injection of AMD3100. To determine whether AMD3100 mobilized cells would be suitable for allografting, we performed a detailed phenotypic analysis using 6 color flow cytometry (CYAN Cytometer MLE) of lymphocyte subsets mobilized following the administration of AMD3100, given as a single 240mcg/kg injection either alone (n=4) or in combination with G-CSF (n=2: G-CSF 10 mcg/kg/day x 5: AMD3100 given on day 4). Baseline peripheral blood (PB) was obtained immediately prior to mobilization; in recipients who received both agents, blood was analyzed 4 days following G-CSF administration as well as 12 hours following administration of AMD3100 and a 5th dose of G-CSF. AMD3100 alone significantly increased from baseline the PB WBC count (2.8 fold), Absolute lymphocyte count (ALC: 2.5 fold), absolute monocyte count (AMC: 3.4 fold), and absolute neutrophil count (ANC: 2.8 fold). Subset analysis showed AMD3100 preferentially increased from baseline PB CD34+ progenitor counts (5.8 fold), followed by CD19+ B-cells (3.7 fold), CD14+ monocytes (3.4 fold), CD8+ T-cells (2.5 fold), CD4+ T-cells (1.8 fold), with a smaller increase in CD3−/CD16+ or CD56+ NK cell counts (1.6 fold). There was no change from baseline in the % of CD4+ or CD8+ T-cell expressing CD45RA, CD45RO, or CD56, CD57, CD27, CD71 or HLA-DR. In contrast, there was a decline compared to baseline in the mean percentage of CD3+/CD4+ T-cells expressing CD25 (5.5% vs 14.8%), CD62L (12.1% vs 41.1%), CCR7 (2.1% vs 10.5%) and CXCR4 (0.5% vs 40.9%) after AMD3100 administration; similar declines in expression of the same 4 surface markers were also observed in CD3+/CD8+ T-cells. A synergistic effect on the mobilization of CD34+ progenitors, CD19+ B cells, CD3+ T-cells and CD14+ monocytes occurred when AMD3100 was combined with G-CSF (Figure). In those receiving both AMD3100 and G-CSF, a fall in the % of T-cells expressing CCR7 and CXCR4 occurred 12 hours after the administration of AMD3100 compared to PB collected after 4 days of G-CSF; no other differences in the expression of a variety activation and/or adhesion molecules on T-cell subsets were observed. Whether differences in lymphocyte subsets mobilized with AMD3100 alone or in combination with G-CSF will impact immune reconstitution or other either immune sequela (i.e. GVHD, graft-vs-tumor) associated with allogeneic HCT is currently being assessed in an animal model of allogeneic transplantation.

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