T-bet Over-Expression in T Cells from Patients with Aplastic Anemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 832-832
Author(s):  
Elena E. Solomou ◽  
Keyvan Keyvanfar ◽  
Elaine M. Sloand ◽  
Barbara Weinstein ◽  
Olga Nunez ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Transcription Factors ◽  
Hematopoietic Stem ◽  
T Box ◽  
Protein Levels ◽  
Proximal Site ◽  
Ifn Γ ◽  
Bet Protein ◽  
Normal Controls

Abstract Acquired aplastic anemia (AA) is a bone marrow failure syndrome characterized by immune-mediated destruction of hematopoietic stem cells. T cells from patients with AA overproduce IFN-γ, a cytokine that inhibits hematopoietic stem cell proliferation and induces Fas-mediated apoptosis; stem cell depletion results in marrow hypoplasia and peripheral blood pancytopenia. In T cells, regulation of IFN-γ production occurs primarily at the level of transcription. A proximal site of the IFN-γ gene (−75 to −45bp of the IFN-γ promoter) is a binding site for different transcription factors including NFAT, AP-1, ATF, CREB, and T-bet. T-bet is a member of the T-box family of transcription factors, this family contains a highly conserved DNA binding domain, the T-box, that binds to a specific sequence in the promoter of different genes, including the IFN-γ promoter. T-bet is found in Th1 but not in Th2 cells and is the key regulator of Th1 development and function (Rengarajan et al., Immunol Today2000; 21: 479). The inducible expression of T-bet is mediated in part by Itk kinase (Sjabo et al., Science2005; 307: 430). In the present study, we examined T-bet protein levels in T cells from patients with AA. Samples from 17 of 20 patients examined (85%) by immunoblot showed increased T-bet protein levels in unstimulated T cells compared to normal controls (p = 0.0001). Normal controls showed undetectable T-bet protein levels in unstimulated T cells but T-bet expression was induced after 24 hrs of stimulation with PMA and ionomycin. In electrophoretical mobility shift assays, we observed increased T-bet binding to the proximal site of the IFN-γ promoter in T cells from patients with AA; no binding was detected in unstimulated T cells from healthy controls, but binding was present after stimulation for at least 24 hrs. T-bet protein levels correlated with disease activity. Patients with increased T-bet protein levels showed increased intracellular IFN-g levels compared to controls, as detected by flow cytometry (p<0.05). Patients that expressed increased T-bet protein levels also showed increased levels of the Itk kinase (p=0.02). We examined if other kinases that lie downstream of Itk in the signal transduction activation cascade in T cells affected the inducible expression of T-bet. In normal T cells, rottlerin, a PKC-theta (PKC-𝛉) inhibitor, decreased T-bet protein levels by 50%; in AA T cells, rottlerin also decreased T-bet protein levels and IFN-γ intracellular levels by 50%. Our results suggest that the increased IFN-γ levels observed in AA are the result of activation of transcription of the IFN-γ gene by the regulator T-bet. Blocking of transcription of the IFN-γ gene by kinase inhibitors might represent a therapuetic strategy for AA and other human T cell-mediated autoimmune diseases.

Functional Comparison and Longitudinal Assessment of Tri-Functional T-Cells Recognizing CMV pp65 and IE-1 Polypeptides in Hematopoietic Stem Cell and Solid Organ Transplant Recipients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2936-2936
Author(s):  
Don J. Diamond ◽  
Simon F. Lacey ◽  
Corinna La Rosa ◽  
Wendy Zhou ◽  
Ghislaine Gallez-Hawkins ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Solid Organ ◽  
Transplant Recipients ◽  
Hematopoietic Stem ◽  
Specific Ctls ◽  
Tnf Α ◽  
Ifn Γ ◽  
Cmv Disease

Abstract Reconstitution of adaptive T-cell responses to human cytomegalovirus (CMV) is critical to protection from CMV disease following hematopoietic stem cell (HSCT) or solid organ transplantation (SOT). However, there is an incomplete understanding of which CMV antigens and epitopes are most crucial to providing protective responses. The functional status of cytotoxic T-lymphocyte (CTL) populations recognizing cytomegalovirus IE-1 and pp65 polypeptides was investigated in PBMC from either HSCT or SOT recipients. Our previous finding of differing levels of degranulation between CMV IE1 and pp65/pp50 specific T-cells was complicated by the possibility that differences were epitope and/or HLA-specific. We generalized the approach using a combined flow-based CD107a/b degranulation/mobilization and intracellular cytokine (ICC) assays using peptide libraries as antigens. These assays indicated that a significantly higher proportion of pp65-specific CTLs were in a more mature functional state compared to IE-1-specific CTLs. Degranulation/multicytokine ICC assays also indicated that a significantly higher proportion of the pp65-specific versus IE-1-specific CTLs secreted both IFN-γ and TNF-α, in addition to possessing greater cytotoxic potential. These results support our earlier findings of functional differences between CTLs recognizing individual epitopes within the IE-1 and pp65 antigens in HSCT recipients, and extend them to a broader array of HLA-restricted responses to those antigens. A report that a subset of HIV-1 specific CTLs capable of producing both IFN-γ and TNF-α was associated with improved cytotoxic activity prompted us to investigate whether degranulation, a functional correlate of cytotoxicity, was positively associated with dual cytokine production and predicted differences between IE1 and pp65-specific CD8+ T-cells. A higher proportion of pp65-specific compared to IE1-specific T-cells were present in the trifunctional IFN-γ+,TNF-α+, CD107+ population (p=0.008) in HSCT recipients. We have extended these findings to investigate the role of donor CMV status in terms of functional maturity of CMV-specific T cell response in transplant recipients. T cell maturation/function may act as a mechanistic correlate to the survival advantage of recipients receiving a stem-cell graft from CMV sero-positive donors. These principles have also been applied to investigations of a high risk population of sero-negative recipients of a sero-positive liver allograft. Data from this study will also be reviewed in the context of the model of trifunctional T cells being indicative of enhanced protective capacity against CMV disease and associated with survival.

scholarly journals T-bet, a Th1 transcription factor, is up-regulated in T cells from patients with aplastic anemia

Blood ◽  
2006 ◽  
Vol 107 (10) ◽  
pp. 3983-3991 ◽  
Author(s):  
Elena E. Solomou ◽  
Keyvan Keyvanfar ◽  
Neal S. Young
Keyword(s):  
T Cells ◽  
Transcription Factor ◽  
Aplastic Anemia ◽  
Kinase Inhibitors ◽  
Bone Marrow Failure ◽  
Hematopoietic Cells ◽  
T Box ◽  
Proximal Site ◽  
Active Transcription ◽  
Ifn Γ

In aplastic anemia, immune destruction of hematopoietic cells results in bone marrow failure. Type 1 cytokines, especially IFN-γ, have been implicated in the pathophysiology of T-cell–mediated, Fas-mediated stem cell apoptosis of hematopoietic cells. Here, we show that the transcription factor T-bet (T-box expressed in T cells) is increased in T cells from patients with aplastic anemia. Patients' T-bet bound directly to the proximal site of the IFN-γ promoter without any prior stimulation, in contrast to healthy controls. Increased levels of Itk kinase participated in T-bet up-regulation and active transcription of the IFN-γ gene observed in these patients. Blocking PKC-θ, a kinase that lies downstream of Itk kinase, decreased T-bet protein and IFN-γ intracellular levels. These data suggest that the increased IFN-γ levels observed in aplastic anemia patients are the result of active transcription of the IFN-γ gene by T-bet. Blocking the transcription of the IFN-γ gene with kinase inhibitors might lead to the development of novel therapeutic agents for patients with aplastic anemia and other autoimmune diseases.

scholarly journals IFN-γ and indoleamine 2,3-dioxygenase signaling between donor dendritic cells and T cells regulates graft versus host and graft versus leukemia activity

Blood ◽  
2012 ◽  
Vol 119 (4) ◽  
pp. 1075-1085 ◽  
Author(s):  
Ying Lu ◽  
Cynthia R. Giver ◽  
Akshay Sharma ◽  
Jian Ming Li ◽  
Katarzyna A. Darlak ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Graft Versus Host ◽  
Graft Versus Leukemia ◽  
Donor T Cells ◽  
Ifn Γ

Abstract Allogeneic hematopoietic stem cell transplantation (HSCT) can eradicate chemorefractory leukemia through the graft-versus-leukemia (GVL) activity of donor T cells. However, the clinical success of allo-HSCT is limited by the graft-versus-host disease (GVHD) activity of donor T cells. We have reported previously that donor bone marrow precursors of plasmacytoid dendritic cells (pre-pDCs) can activate donor T cells toward T-helper 1 immune polarization in murine allogeneic HSCT. To optimize the GVL activity of these activated donor T cells and limit their graft versus host activity, we engineered the cellular constituents of an allogeneic hematopoietic stem cell graft with highly purified hematopoietic stem cells, T cells, and pre-pDCs and studied their GVL and GVHD activities in a murine model of allogeneic HSCT. Transplanted donor pre-pDCs expanded in vivo for 2 weeks after transplant, and they markedly augmented the activation and GVL activity of donor T cells while attenuating their GVHD activity, leading to an improved therapeutic index. Bidirectional signaling between donor T cells and donor pDCs with IFN-γ synthesis by donor T cells inducing indoleamine 2,3-dioxygenase synthesis by donor pDCs limited GVHD by altering the balance between donor T-reg and inflammatory T cells. Manipulating the content of donor DC precursors in allogeneic HSCT is a novel method to optimize the balance between GVL and GVHD.

IL-12hi Rapamycin-Conditioned Dendritic Cells Mediate IFN-γ-Dependent Apoptosis of Alloreactive CD4+ T Cells and Limit Graft-Versus-Host Diseas

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4110-4110
Author(s):  
Elizabeth O. Stenger ◽  
Brian R. Rosborough ◽  
Lisa Mathews ◽  
Huihui Ma ◽  
Markus Mapara ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Cell Apoptosis ◽  
Cd4 T Cells ◽  
Annexin V ◽  
Hematopoietic Stem ◽  
Graft Versus Host ◽  
T Cell Apoptosis ◽  
Ifn Γ

Abstract Abstract 4110 Introduction: Rapamycin (RAPA) inhibits the serine/threonine kinase mammalian Target of Rapamycin to profoundly modulate immune cell function. Dendritic cells (DC) exposed to RAPA (RAPA-DC) exhibit tolerogenic properties, including promotion of experimental cardiac allograft survival. RAPA-DC enrich for CD4+FoxP3+ regulatory T cells and induce alloreactive T cell apoptosis and anergy. Yet, paradoxically, RAPA-DC secrete increased IL-12, which is central for the generation of IFN-γ+CD4+ T helper type 1 cells. IFN-γ can be pro-apoptotic, and IL-12-driven IFN-γ inhibits graft-versus-host disease (GVHD) following hematopoietic stem cell transplantation. We hypothesized that IL-12hi RAPA-DC, unlike control (CTR)-DC, would be effective in the prevention of GVHD by supporting IFN-γ-mediated apoptosis of alloreactive T cells. Methods: DC were generated from C57BL/6 (H2-b) or B6.129S7-Ifngr1tm1Agt/J (IFN-γ-R−/− [H2-b]) bone marrow (BM) in 7 day (d) culture in the absence (CTR-DC) or presence of RAPA (RAPA-DC). CTR- and RAPA-DC cultures remained either untreated or were stimulated via TLR4 with LPS (100 ng/ml) for an additional 18 hours. Washed and CD11c+ purified DC from these groups were then used as stimulators of allogeneic CD4+ T cells (BALB/c [H2-d] or CByJ.129S7(B6)-Ifngr1tm1Agt/J [IFN-γ-R−/− {H2-d}]) in 5 d mixed leukocyte reaction (MLR) with or without anti-IFN-γ antibody. T cell apoptosis was quantified using an Annexin V Apoptosis Detection kit. The capacity of DC to prevent GVHD was assessed in irradiated BALB/c mice reconstituted with 5×106 T cell-depleted B6 BM on d0. Recipient mice received 1×106 CD11c+ BALB/c DC (CTR-, RAPA-, or LPS-exposed DC) on d0 and 1×106 B6 T cells on d1. Mice were monitored daily, and moribund mice or those with >20% weight loss were euthanized. Results: Compared to CTR-DC, especially when LPS-stimulated, RAPA-DC induced increased apoptosis (Annexin V+7-AAD+) of alloreactive CD4+ T cells in MLR (13.9±1.6% versus 7.1±0.2%; +LPS: 30.6±3.4% versus 14.7±3.6%; both p<0.05). Neutralization of IFN-γ in co-cultures containing LPS-stimulated RAPA-DC decreased levels of apoptosis to those of LPS-exposed CTR-DC (18.5±1.3% versus 14.7±3.6%; NS). IFN-γ-R−/− CD4+ T cells exposed to LPS-stimulated IL-12hi RAPA-DC exhibited decreased apoptosis when compared to wild-type CD4+ T cells (WT 15.7±3.6% versus IFN-γ-R−/− 4.9±1.1%; p<0.05) (Figure 1). There was no difference in the extent of apoptosis of alloreactive CD4+ T cells induced by IFN-γ-R−/− RAPA-DC compared to WT RAPA-DC (10.6±7.6% versus 12.4±7.6% respectively; +LPS: 30.1±16.3% versus 27.3±12.0%; both p=NS) (Figure 2). The addition of anti-IFN-γ mAb to LPS-stimulated IFN-γ-R−/− RAPA-DC significantly decreased levels of CD4+ T cell apoptosis comparable to LPS-stimulated WT CTR-DC (18.0±10.3% versus 22.0±6.3%, p<0.05). Depletion of IFN-γ did not impact on the Treg-enriching capacity (CD4hiFoxP3+/CD4hiFoxP3−) of RAPA-DC (24.2±0.4% versus 29.2±6.2% with anti-IFN-γ mAb; p=NS). Further, whereas CTR-DC and LPS-exposed CTR-DC did not prolong survival, IL-12hi RAPA-DC significantly prolonged survival from GVHD (median survival in days: GVHD, 17.5 d; RAPA-DC, 27 d, p=NS compared to GVHD; RAPA-DC + LPS, 35 d, p<0.01; syngeneic control, >50 d, p<0.01) (Figure 3). In contrast, CTR-DC had comparable GVHD mortality (21 d, p=NS). Conclusions: Increased apoptosis induced by LPS-stimulated IL-12hi RAPA-DC is mediated directly on CD4+ allogeneic T cells via IFN-γ and not through actions on DC. Thus, increased IL-12 may support IFN-γ-mediated activation-induced cell death while sparing regulatory T cells and may underlie the capacity of LPS-exposed RAPA-DC to prevent GVHD. IL-12hi human RAPA-DC, generated with the aid of endotoxin-free, synthetic TLR4 agonists, may offer a means to harness the demonstrated capacity of both IL-12 and tolerogenic DC to prevent GVHD following hematopoietic stem cell transplant. Disclosures: No relevant conflicts of interest to declare.

The Expression Pattern of TCR Vγ I∼III Subfamilies in GVHD Patients After Allogenic Hematopoietic Stem Cell Transplantation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2219-2219
Author(s):  
Xiuli Wu ◽  
Can Liu ◽  
Yu Zhang ◽  
Zhiping Fan ◽  
Qifa Liu
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Expression Pattern ◽  
Expression Patterns ◽  
Γδ T Cells ◽  
Rt Pcr ◽  
Hematopoietic Stem ◽  
Normal Controls

Abstract Abstract 2219 Poster Board II-196 Objective The γΔ+ T cells can act as a vast functional setting of immune defense against pathogenic invaders in chronic inflammatory reactions, as well as in modulating systemic and organ-specific autoimmune diseases. Recently, it was reported that γΔ+ T cells might play an important role in regulation of graft versus host disease (GVHD), mediation of graft versus leukemia effect, anti-virus infection, anti-cancer effect and so on. But the frequency of T cell receptor (TCR) Vγ repertoire and the expression patterns of TCR Vγ subfamilies in GVHD remain unknown. To further study on the characteristics of TCR Vγ subfamilies in GVHD, we investigated the frequency of TCR Vγ repertoire and the expression of TCR Vγ I∼III subfamilies genes in the patients with GVHD after allogenic hematopoietic stem cell transplantation (allo-HSCT). Methods The expression and cloanlity analysis of TCR Vγ repertoire was detected in peripheral blood mononuclear cells (PBMNCs) from 25 patients with GVHD by RT-PCR and genescan technique. The TCR Vγ I∼III genes expression levels of PBMNCs from patients with GVHD were detected using the real-time fluorescence quantitative polymerase chain reaction with SYBR Green I technique and relative quantification method. Twelve healthy individuals served as normal controls. Results The RT-PCR results showed that in GVHD patients, the expression frequency of TCR Vγ I was 88.0% (22/25), TCR Vγ II was 72.0% (18/25), and TCR Vγ III was 96.0% (24/25). All of the three TCR Vγ subfamilies could be detected in PBMNCs from the normal controls. TCR Vγ repertoires with polyclonal pattern were identified in normal controls. However, the skew expression pattern of TCR Vγ repertoire could be detected in patients with GVHD even more than 4 year after allo-HSCT. Oligoclonal or monoclonal expanded T cells were identified in TCR Vγ I∼III subfamilies in GVHD patients. The expression level of TCR Vγ II gene in the PBMNCs from patients with GVHD was significant lower than the normal controls (P<0.05). The pattern of TCR Vγ gene expression levels in GVHD was TCR Vγ I> TCR Vγ III> TCR Vγ II, however, the expression pattern in normal controls was TCR Vγ II> TCR Vγ I > TCR Vγ III. Conclusions The expression patterns of TCR Vγ I∼III subfamilies were changed in GVHD. The low expression of TCR Vγ II subfamily might be related with the pathogenesis of GVHD. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Impaired interferon-γ production as a consequence of STAT4 deficiency after autologous hematopoietic stem cell transplantation for lymphoma

Blood ◽  
2005 ◽  
Vol 106 (3) ◽  
pp. 963-970 ◽  
Author(s):  
Michael J. Robertson ◽  
Hua-Chen Chang ◽  
David Pelloso ◽  
Mark H. Kaplan
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Tyrosine Phosphorylation ◽  
Cell Transplantation ◽  
Cd4 T Cells ◽  
Interferon Γ ◽  
Hematopoietic Stem ◽  
Patient Pbmcs ◽  
Ifn Γ

AbstractProduction of interferon γ (IFN-γ) is critical for optimal antitumor immunotherapy in several preclinical animal models. Interleukin-12 (IL-12)–induced IFN-γ production is markedly defective after autologous stem cell transplantation. Quantitative deficiency in CD4 T cells, relative increase in CD25+CD4+ T cells, and bias toward T helper 2 (Th2) differentiation are not the primary mechanisms of defective IFN-γ production. IL-12 receptor β1 (IL-12Rβ1) and IL-12Rβ2 are expressed at equivalent or higher levels on posttransplantation patient peripheral blood mononuclear cells (PBMCs) as compared with control PBMCs. IL-12–induced tyrosine phosphorylation of signal transducer and activator of transcription 4 (STAT4) was undetectable or barely detectable in posttransplantation patient PBMCs, whereas IL-4–induced tyrosine phosphorylation of STAT6 did not differ in posttransplantation patient and control PBMCs. Levels of STAT4 protein were decreased by 97% in posttransplantation patient PBMCs. Levels of STAT4 mRNA were also significantly decreased in posttransplantation patient PBMCs. Incubation with IL-12 and IL-18 in combination partially reversed the defective IFN-γ production by posttransplantation patient PBMCs. IFN-γ production in response to IL-12 plus IL-18 did not require increased expression of STAT4 but was dependent on the activity of p38 mitogen-activated protein kinase (MAPK). These results indicate that defective IFN-γ production is due to an intrinsic deficiency in STAT4 expression by posttransplantation patient lymphocytes and suggest strategies for circumventing this deficiency in cancer immunotherapy.

scholarly journals Increase of Regulatory γδ T Cells Reduces the Incidence of Acute Graft-Versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2230-2230 ◽  
Author(s):  
Li Gao ◽  
Li Xuan ◽  
Xiuli Wu ◽  
Zhiping Fan ◽  
Fen Huang ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Γδ T Cells ◽  
Hematopoietic Stem ◽  
Expression Levels ◽  
Graft Versus Host ◽  
Tnf Α ◽  
Ifn Γ ◽  
Acute Graft

Abstract Background Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the primary means for treatment of hematologic and non-hematologic malignancies. Acute graft-versus-host disease (aGVHD) is a major complication associated with high morbidity and mortality after transplantation. Regulatory γδ T cells (γδ Tregs), as a novel subset of γδ T cells with Foxp3 expression and immunosuppressive effect, are found to effectively alleviate aGVHD in mice model. However, whether γδ Tregs involve in the occurrence of aGVHD in recipients of allo-HSCT remains unclear. Therefore, the aim of this study is to investigate the effect of γδ Tregs in the occurrence of aGVHD in recipients of allo-HSCT. Methods The immunophenotyping of γδ Tregs was analyzed in peripheral blood from 24 aGVHD and 24 paired non-aGVHD patients (undergoing transplantation at the same time, basic data matched), using flow cytometry. The expression levels of immunoregulatory-associated molecules (Foxp3, CD25, CTLA-4, GITR, TLR8, RORc, STAT-1 and STAT-3) were analyzed in peripheral blood, using real-time RT-PCR with SYBR GreenⅠstaining. Liquichip technology was used to analyze the concentration of interferon-γ (IFN-γ), interleukin-4 (IL-4), IL-10, IL-17 and tumour necrosis factor-α (TNF-α) in cultural supernatant. Results The proportions of total γδ T and Vδ2 T cells in non-aGVHD patients were significantly higher than that in aGVHD patients (P=0.044, P=0.000), and the proportion of Vδ1 T cells was similar between the two groups (P=0.061). Compared with aGVHD patients, the proportions of Foxp3+γδ T, Foxp3+Vδ1 T, Foxp3+Vδ2 T cells and Tregs were increased in non-aGVHD patients (P=0.005, P=0.014, P=0.026 and P=0.000). There was a negative correlation between the incidence of aGVHD and the percentages of Foxp3+γδ T, Foxp3+Vδ1 T and Foxp3+Vδ2 T cells (P=0.014, rs=-0.477; P=0.001, rs=-0.610; P=0.040, rs=-0.405). The mRNA expression levels of Foxp3 and TLR8 genes were significantly increased in non-aGVHD patients compared with aGVHD patients (P=0.042, P=0.002). There were no significant difference in the expression levels of CD25, RORc, CTLA-4, GITR, STAT-1 and STAT-3 genes (P=0.234, P=0.194, P=0.056, P=0.524, P=0.142 and P=0.775). In addition, the concentrations of IL-10 and TNF-α were significantly increased in aGVHD patients (P=0.002, P=0.036), and the concentrations of IL-4, IL-17 and IFN-γ were similar between the two groups (P=0.379, P=0.414, P=0.170). Conclusions Increase of γδ Tregs might reduce the incidence of aGVHD after allo-HSCT. Disclosures No relevant conflicts of interest to declare.

scholarly journals Comparison of Cytomegalovirus-Specific Immune Cell Response to Proteins versus Peptides Using an IFN-γ ELISpot Assay after Hematopoietic Stem Cell Transplantation

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 312
Author(s):  
Eva Wagner-Drouet ◽  
Daniel Teschner ◽  
Christine Wolschke ◽  
Kerstin Schäfer-Eckart ◽  
Johannes Gärtner ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Cell Response ◽  
Elispot Assay ◽  
Cmv Infection ◽  
Hematopoietic Stem ◽  
Ifn Γ ◽  
Antigen Presenting

Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality following hematopoietic stem cell transplantation (HSCT). Measuring CMV-specific cellular immunity may improve the risk stratification and management of patients. IFN-γ ELISpot assays, based on the stimulation of peripheral blood mononuclear cells with CMV pp65 and IE-1 proteins or peptides, have been validated in clinical settings. However, it remains unclear to which extend the T-cell response to synthetic peptides reflect that mediated by full-length proteins processed by antigen-presenting cells. We compared the stimulating ability of pp65 and IE-1 proteins and corresponding overlapping peptides in 16 HSCT recipients using a standardized IFN-γ ELISpot assay. Paired qualitative test results showed an overall 74.4% concordance. Discordant results were mainly due to low-response tests, with one exception. One patient with early CMV reactivation and graft-versus-host disease, sustained CMV DNAemia and high CD8+ counts showed successive negative protein-based ELISpot results but a high and sustained response to IE-1 peptides. Our results suggest that the response to exogenous proteins, which involves their uptake and processing by antigen-presenting cells, more closely reflects the physiological response to CMV infection, while the response to exogenous peptides may lead to artificial in vitro T-cell responses, especially in strongly immunosuppressed patients.

scholarly journals Reduced dose of PTCy followed by adjuvant α-galactosylceramide enhances GVL effect without sacrificing GVHD suppression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Makoto Nakamura ◽  
Yusuke Meguri ◽  
Shuntaro Ikegawa ◽  
Takumi Kondo ◽  
Yuichi Sumii ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell Subsets ◽  
Inkt Cells ◽  
Early Recovery ◽  
Hematopoietic Stem ◽  
Graft Versus Host ◽  
Reduced Dose ◽  
Graft Versus Leukemia ◽  
Novel Strategy

AbstractPosttransplantation cyclophosphamide (PTCy) has become a popular option for haploidentical hematopoietic stem cell transplantation (HSCT). However, personalized methods to adjust immune intensity after PTCy for each patient’s condition have not been well studied. Here, we investigated the effects of reducing the dose of PTCy followed by α-galactosylceramide (α-GC), a ligand of iNKT cells, on the reciprocal balance between graft-versus-host disease (GVHD) and the graft-versus-leukemia (GVL) effect. In a murine haploidentical HSCT model, insufficient GVHD prevention after reduced-dose PTCy was efficiently compensated for by multiple administrations of α-GC. The ligand treatment maintained the enhanced GVL effect after reduced-dose PTCy. Phenotypic analyses revealed that donor-derived B cells presented the ligand and induced preferential skewing to the NKT2 phenotype rather than the NKT1 phenotype, which was followed by the early recovery of all T cell subsets, especially CD4+Foxp3+ regulatory T cells. These studies indicate that α-GC administration soon after reduced-dose PTCy restores GVHD-preventing activity and maintains the GVL effect, which is enhanced by reducing the dose of PTCy. Our results provide important information for the development of a novel strategy to optimize PTCy-based transplantation, particularly in patients with a potential relapse risk.

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