Evidence for naive T-cell repopulation despite thymus irradiation after autologous transplantation in adults with multiple myeloma: role of ex vivo CD34+ selection and age

Blood ◽  
2003 ◽  
Vol 101 (5) ◽  
pp. 1891-1897 ◽  
Author(s):  
Marion Malphettes ◽  
Guislaine Carcelain ◽  
Pierre Saint-Mezard ◽  
Véronique Leblond ◽  
Hester Korthals Altes ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Autologous Transplantation ◽  
High Dose ◽  
T Cell Reconstitution ◽  
Unselected Group ◽  
Cell Repopulation

Immunodeficiency following autologous CD34+-purified peripheral blood stem cell (PBSC) transplantation could be related to T-cell depletion of the graft or impaired T-cell reconstitution due to thymus irradiation. Aiming to assess the role of irradiated thymus in T-cell repopulation, we studied 32 adults with multiple myeloma, randomly assigned to receive high-dose therapy including total body irradiation (TBI) followed by autologous transplantation with either unselected or CD34+-selected PBSCs. The median number of reinfused CD3+ cells was lower in the selected group (0.03 versus 14 × 106/kg; P = .002). Lymphocyte subset counts were evaluated from month 3 to 24 after grafting. Naive CD4+ T cells were characterized both by phenotype and by quantification of T-cell receptor rearrangement excision circles (TRECs). The reconstitution of CD3+ and CD4+ T cells was significantly delayed in the CD34+-selected group, but eventually led to counts similar to those found in the unselected group after month 12. Mechanism of reconstitution differed, however, between both groups. Indeed, a marked increase in the naive CD62L+CD45RA+CD4+subset was observed in the selected group, but not in the unselected group in which half of the CD45RA+CD4+ T cells appear to be CD62L−. Age was identified as an independent adverse factor for CD4+ and CD62L+CD45RA+CD4+ T-cell reconstitution. Our results provide evidence that infusing PBSCs depleted of T cells after TBI in adults delays T-cell reconstitution but accelerates thymic regeneration.

scholarly journals Ceramide Synthase 2 Null Mice Are Protected from Ovalbumin-Induced Asthma with Higher T Cell Receptor Signal Strength in CD4+ T Cells

2021 ◽  
Vol 22 (5) ◽  
pp. 2713
Author(s):  
Sun-Hye Shin ◽  
Kyung-Ah Cho ◽  
Hee-Soo Yoon ◽  
So-Yeon Kim ◽  
Hee-Yeon Kim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cd4 T Cells ◽  
Acyl Chain ◽  
Signal Strength ◽  
Cell Receptor ◽  
Ceramide Synthase ◽  
Asthmatic Patients

(1) Background: six mammalian ceramide synthases (CerS1–6) determine the acyl chain length of sphingolipids (SLs). Although ceramide levels are increased in murine allergic asthma models and in asthmatic patients, the precise role of SLs with specific chain lengths is still unclear. The role of CerS2, which mainly synthesizes C22–C24 ceramides, was investigated in immune responses elicited by airway inflammation using CerS2 null mice. (2) Methods: asthma was induced in wild type (WT) and CerS2 null mice with ovalbumin (OVA), and inflammatory cytokines and CD4 (cluster of differentiation 4)+ T helper (Th) cell profiles were analyzed. We also compared the functional capacity of CD4+ T cells isolated from WT and CerS2 null mice. (3) Results: CerS2 null mice exhibited milder symptoms and lower Th2 responses than WT mice after OVA exposure. CerS2 null CD4+ T cells showed impaired Th2 and increased Th17 responses with concomitant higher T cell receptor (TCR) signal strength after TCR stimulation. Notably, increased Th17 responses of CerS2 null CD4+ T cells appeared only in TCR-mediated, but not in TCR-independent, treatment. (4) Conclusions: altered Th2/Th17 immune response with higher TCR signal strength was observed in CerS2 null CD4+ T cells upon TCR stimulation. CerS2 and very-long chain SLs may be therapeutic targets for Th2-related diseases such as asthma.

scholarly journals Isolevuglandin-Modified Cardiac Proteins Drive CD4+ T Cell Activation in the Heart and Promote Cardiac Dysfunction

Circulation ◽  
2021 ◽  
Author(s):  
Njabulo Ngwenyama ◽  
Annet Kirabo ◽  
Mark Aronovitz ◽  
Francisco Velázquez ◽  
Francisco Carrillo-Salinas ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
T Cell Activation ◽  
Cardiac Dysfunction ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
Myocardial Oxidative Stress

Background: Despite the well-established association between T cell-mediated inflammation and non-ischemic heart failure (HF), the specific mechanisms triggering T cell activation during the progression of HF and the antigens involved are poorly understood. We hypothesized that myocardial oxidative stress induces the formation of isolevuglandin (IsoLG)-modified proteins that function as cardiac neoantigens to elicit CD4+ T cell receptor (TCR) activation and promote HF. Methods: We used transverse aortic constriction (TAC) in mice to trigger myocardial oxidative stress and T cell infiltration. We profiled the TCR repertoire by mRNA sequencing of intramyocardial activated CD4+ T cells in Nur77 GFP reporter mice, which transiently express GFP upon TCR engagement. We assessed the role of antigen presentation and TCR specificity in the development of cardiac dysfunction using antigen presentation-deficient MhcII -/- mice, and TCR transgenic OTII mice that lack specificity for endogenous antigens. We detected IsoLG-protein adducts in failing human hearts. We also evaluated the role of reactive oxygen species (ROS) and IsoLGs in eliciting T cell immune responses in vivo by treating mice with the antioxidant TEMPOL, and the IsoLG scavenger 2-hydroxybenzylamine (2-HOBA) during TAC, and ex-vivo in mechanistic studies of CD4+ T cell proliferation in response to IsoLG-modified cardiac proteins. Results: We discovered that TCR antigen recognition increases in the left ventricle (LV) as cardiac dysfunction progresses, and identified a limited repertoire of activated CD4+ T cell clonotypes in the LV. Antigen presentation of endogenous antigens was required to develop cardiac dysfunction since MhcII -/- mice reconstituted with CD4+ T cells, and OTII mice immunized with their cognate antigen were protected from TAC-induced cardiac dysfunction despite the presence of LV-infiltrated CD4+ T cells. Scavenging IsoLGs with 2-HOBA reduced TCR activation and prevented cardiac dysfunction. Mechanistically, cardiac pressure overload resulted in ROS dependent dendritic cell accumulation of IsoLG-protein adducts which induced robust CD4+ T cell proliferation. Conclusions: Collectively, our study demonstrates an important role of ROS-induced formation of IsoLG-modified cardiac neoantigens that lead to TCR-dependent CD4+ T cell activation within the heart.

scholarly journals CD4+ T-cell killing of multiple myeloma cells is mediated by resident bone marrow macrophages

2020 ◽  
Vol 4 (12) ◽  
pp. 2595-2605 ◽  
Author(s):  
Ole Audun W. Haabeth ◽  
Kjartan Hennig ◽  
Marte Fauskanger ◽  
Geir Åge Løset ◽  
Bjarne Bogen ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Antigen Presenting Cells ◽  
Bone Marrow Microenvironment ◽  
Cd4 T Cell ◽  
Myeloma Cells ◽  
Antigen Presenting

Abstract CD4+ T cells may induce potent antitumor immune responses through interaction with antigen-presenting cells within the tumor microenvironment. Using a murine model of multiple myeloma, we demonstrated that adoptive transfer of idiotype-specific CD4+ T cells may elicit curative responses against established multifocal myeloma in bone marrow. This finding indicates that the myeloma bone marrow niche contains antigen-presenting cells that may be rendered tumoricidal. Given the complexity of the bone marrow microenvironment, the mechanistic basis of such immunotherapeutic responses is not known. Through a functional characterization of antitumor CD4+ T-cell responses within the bone marrow microenvironment, we found that killing of myeloma cells is orchestrated by a population of bone marrow–resident CD11b+F4/80+MHC-IIHigh macrophages that have taken up and present secreted myeloma protein. The present results demonstrate the potential of resident macrophages as powerful mediators of tumor killing within the bone marrow and provide a basis for novel therapeutic strategies against multiple myeloma and other malignancies that affect the bone marrow.

scholarly journals The critical role of CD4+ T cells in PD-1 blockade against MHC-II–expressing tumors such as classic Hodgkin lymphoma

2020 ◽  
Vol 4 (17) ◽  
pp. 4069-4082
Author(s):  
Joji Nagasaki ◽  
Yosuke Togashi ◽  
Takeaki Sugawara ◽  
Makiko Itami ◽  
Nobuhiko Yamauchi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Critical Role ◽  
Cd4 T Cell ◽  
Antitumor Effects ◽  
Cell Axis ◽  
Mhc I ◽  
Mhc Ii

Abstract Classic Hodgkin lymphoma (cHL) responds markedly to PD-1 blockade therapy, and the clinical responses are reportedly dependent on expression of major histocompatibility complex class II (MHC-II). This dependence is different from other solid tumors, in which the MHC class I (MHC-I)/CD8+ T-cell axis plays a critical role. In this study, we investigated the role of the MHC-II/CD4+ T-cell axis in the antitumor effect of PD-1 blockade on cHL. In cHL, MHC-I expression was frequently lost, but MHC-II expression was maintained. CD4+ T cells highly infiltrated the tumor microenvironment of MHC-II–expressing cHL, regardless of MHC-I expression status. Consequently, CD4+ T-cell, but not CD8+ T-cell, infiltration was a good prognostic factor in cHL, and PD-1 blockade showed antitumor efficacy against MHC-II–expressing cHL associated with CD4+ T-cell infiltration. Murine lymphoma and solid tumor models revealed the critical role of antitumor effects mediated by CD4+ T cells: an anti-PD-1 monoclonal antibody exerted antitumor effects on MHC-I−MHC-II+ tumors but not on MHC-I−MHC-II− tumors, in a cytotoxic CD4+ T-cell–dependent manner. Furthermore, LAG-3, which reportedly binds to MHC-II, was highly expressed by tumor-infiltrating CD4+ T cells in MHC-II–expressing tumors. Therefore, the combination of LAG-3 blockade with PD-1 blockade showed a far stronger antitumor immunity compared with either treatment alone. We propose that PD-1 blockade therapies have antitumor effects on MHC-II–expressing tumors such as cHL that are mediated by cytotoxic CD4+ T cells and that LAG-3 could be a candidate for combination therapy with PD-1 blockade.

scholarly journals DC-SIGN–mediated Infectious Synapse Formation Enhances X4 HIV-1 Transmission from Dendritic Cells to T Cells

2004 ◽  
Vol 200 (10) ◽  
pp. 1279-1288 ◽  
Author(s):  
Jean-François Arrighi ◽  
Marjorie Pion ◽  
Eduardo Garcia ◽  
Jean-Michel Escola ◽  
Yvette van Kooyk ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Hiv Infection ◽  
Cd4 T Cells ◽  
Synapse Formation ◽  
Model Systems ◽  
Hiv 1 ◽  
Infectious Synapse

Dendritic cells (DCs) are essential for the early events of human immunodeficiency virus (HIV) infection. Model systems of HIV sexual transmission have shown that DCs expressing the DC-specific C-type lectin DC-SIGN capture and internalize HIV at mucosal surfaces and efficiently transfer HIV to CD4+ T cells in lymph nodes, where viral replication occurs. Upon DC–T cell clustering, internalized HIV accumulates on the DC side at the contact zone (infectious synapse), between DCs and T cells, whereas HIV receptors and coreceptors are enriched on the T cell side. Viral concentration at the infectious synapse may explain, at least in part, why DC transmission of HIV to T cells is so efficient. Here, we have investigated the role of DC-SIGN on primary DCs in X4 HIV-1 capture and transmission using small interfering RNA–expressing lentiviral vectors to specifically knockdown DC-SIGN. We demonstrate that DC-SIGN− DCs internalize X4 HIV-1 as well as DC-SIGN+ DCs, although binding of virions is reduced. Strikingly, DC-SIGN knockdown in DCs selectively impairs infectious synapse formation between DCs and resting CD4+ T cells, but does not prevent the formation of DC–T cells conjugates. Our results demonstrate that DC-SIGN is required downstream from viral capture for the formation of the infectious synapse between DCs and T cells. These findings provide a novel explanation for the role of DC-SIGN in the transfer and enhancement of HIV infection from DCs to T cells, a crucial step for HIV transmission and pathogenesis.

Decrease in CD4+ T Cells in Multiple Myeloma Patients Receiving Bortezomib.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3865-3865
Author(s):  
Ulrike Heider ◽  
Jessica Rademacher ◽  
Martin Kaiser ◽  
Ivana von Metzler ◽  
Karin Marquardt ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
Herpes Zoster ◽  
T Cell ◽  
Peripheral Blood ◽  
Cd4 T Cells ◽  
Proteasome Inhibitor ◽  
Median Number ◽  
Cell Subpopulation ◽  
Cd4 Lymphocytes

Abstract Abstract 3865 Poster Board III-801 The proteasome inhibitor bortezomib is highly effective in multiple myeloma and widely used in this disease. Recently, an increased incidence of opportunistic infections, particularly varicella zoster virus (VZV) reactivation (herpes zoster), was reported in myeloma patients undergoing treatment with bortezomib. We therefore analyzed the influence of bortezomib on lymphocyte subsets, particularly T-cell subpopulations, in the peripheral blood of myeloma patients before initiation and during the treatment. In addition, the results were correlated with the incidence of VZV reactivation. Peripheral blood samples from 53 multiple myeloma patients treated with bortezomib were collected. Eight of the patients were previously untreated and received bortezomib as front-line therapy, whereas 45 patients were treated in the relapse setting. Different subsets of lymphocytes in the peripheral blood were analyzed by four-color flow cytometry. A decrease of CD4+ T-cells was seen in 42/53 patients (77%). The median numbers of CD4+ T-cells decreased by 45% from 494/μl (range 130-2187) to 274/μl (range 41-1404) during therapy with the proteasome inhibitor (p < 0.001). In the majority of the patients (76%), CD4+ lymphocytes dropped to < 400/μl during bortezomib treatment, and in 18/53 patients (33.9%) the CD4+ T cells fell below 200/μl. The minimum CD4+ cell count was seen at a medium of 6 weeks (range 2-22) after the initiation of treatment, but recovered within a few weeks. The median number of circulating CD3+/CD8+ T-cells decreased by 33.6% from 420/μl (range 48-1518) to 279/μl (range 19-1693) during bortezomib therapy (p < 0.001). This was accompanied by a slight decrease of the median CD4/CD8 ratio from 1.17 (range 0.23-6.0) to 1.0 (range 0.15-4.18). Importantly, all of the patients receiving bortezomib as first-line treatment had a normal CD4+ lymphocyte count before initiation of treatment, and all of them showed a decrease of CD3+/ CD4+ cells during the therapy. The median number of circulating CD4+ T-cells in this subgroup decreased by 70% from 924/μl (range 479-1579) to 276/μl (range 80-626) (p < 0.01). The incidence of herpes zoster reactivation was 5.3% in the whole population of myeloma patients receiving bortezomib. 19/53 patients received acyclovir at a dose of 400mg daily as prophylaxis against VZV reactivation. In this group, none of the patients developed herpes zoster. The incidence of VZV reactivation in patients not receiving acyclovir was 3/34 (8.8%). Importantly, occurrence of herpes zoster was associated with reduced CD4+ T cell subpopulation: all patients who developed herpes zoster had CD4+ lymphocytes < 400/μl. In conclusion, our results show that bortezomib leads to a transient decrease in CD4+ lymphocytes, accompanied by an increased incidence of VZV infections. The antiviral prophylaxis with acyclovir is effective in myeloma patients treated with bortezomib. Disclosures: No relevant conflicts of interest to declare.

Co-Existing Serological Immune Responses against RHAMM Might Be a Prerequisite for Strong Cellular Immune Responses of CD8-Positive T Cells in RHAMM-R3 Peptide Vaccination for Patients with Different Hematological Malignancies.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3671-3671
Author(s):  
Jochen Greiner ◽  
Susanne Hofmann ◽  
Krzysztof Giannopoulos ◽  
Markus Rojewski ◽  
Anna Babiak ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
High Dose ◽  
Clinical Effects ◽  
Peptide Vaccination ◽  
Cell Responses ◽  
Tetramer Staining

Abstract Abstract 3671 Poster Board III-607 For effective elimination of malignant cells by specific T cells a co-activation of CD4- and CD8-positive T cells might be important. We performed two RHAMM-R3 peptide vaccination trials using 300μg and 1000μg for patients with AML, MDS and multiple myeloma overexpressing RHAMM. Similar mild toxicity of both cohorts was found, only mild drug-related adverse events were observed such as erythema and induration of the skin. In the 300μg cohort we detected in 7/10 (70 %) patients specific immune responses and also positive clinical effects in 5/10 (50 %) patients. In the high dose peptide vaccination trial (1000μg peptide) 4/9 (44 %) patients showed positive immune responses. These patients showed an increase of CD8+RHAMM-R3 tetramer+/CD45RA+/CCR7-/CD27-/CD28- effector T cells and an increase of R3-specific CD8+ T cells. In the higher peptide dose cohort three patients showed positive clinical effects. However, higher doses of peptide do not improve the frequency and intensity of immune responses in this clinical trial and might induce immune tolerance. In this work, we investigated the co-existence of serological immune responses against RHAMM detected by a RHAMM-specific ELISA of patients with AML, MDS and multiple myeloma treated in these two peptide vaccination trials. We correlated these results to specific T cell responses of CD8-positive T cells measured by ELISpot assays for interferon gamma and Granzyme B, tetramer staining and chromium release assays. Moreover, these results were compared to the frequency of regulatory T cells. 4/19 patients have a positive serological immune response in ELISA assay, all of these patients developed also strong specific CD8-positive T cell responses during peptide vaccination detected by ELISpot assays and tetramer staining. As expected, peptide vaccination did not result in the induction of humoral immune responses. In further ELISA assays we measured IL-2 and IL-10 levels in the sera of the patients before and three weeks after four vaccinations. While IL-10 levels remained at a rather low level over the time of vaccination, we detected an increase of IL-2 up to the five-fold of the initial levels in four of ten patients. Moreover, we performed a proteome array to detect cytokine and chemokine regulation in sera of patients vaccinated in these two trials during and after RHAMM-R3 peptide vaccination. 36 cytokines, chemokines and acute phase proteins were measured and both cohorts vaccinated with different peptide doses were compared. Taken together, RHAMM-R3 peptide vaccination induced both immunological and clinical responses. Co-existence of immune responses of CD4-positive T cells against the target RHAMM seems to be important for an induction of strong immune responses of CD8-positive T cells. Disclosures: No relevant conflicts of interest to declare.

Identification of a Discrete Subpopulation of T-Cells Over-Expressing HDAC11 with a TH17 Phenotype

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 588-588
Author(s):  
Karrune Woan ◽  
Fengdong Cheng ◽  
Hongwei Wang ◽  
Jennifer Rock-Klotz ◽  
Zi Wang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Negative Regulator ◽  
Egfp Expression ◽  
In Vivo Models

Abstract Abstract 588 We recently defined a novel role of histone deacetylase 11 (HDAC11), the newest member of the HDAC family, as a negative regulator of IL-10 gene transcription in antigen-presenting cells (APCs).1 To better understand the role of HDAC11 gene expression in immune cells in vivo, we have utilized a BAC (Bacterial artificial chromosome) transgenic mouse in which the EGFP reporter gene was inserted downstream of the HDAC11 promoter region but immediately upstream of the HDAC11 coding sequence (TgHDAC11-EGFP mice).2 In the steady-state, macrophages and B-cells isolated from spleen of TgHDAC11-EGFP mice express low levels of HDAC11 as evidenced by a slight shift in EGFP fluorescence from background. In sharp contrast, we identified a discrete population (11.9%) of T-cells over-expressing HDAC11 as demonstrated both by flow cytometry for EGFP and by qRT-PCR for HDAC11, a majority of which were CD4+ T-cells. Sorting of this EGFP+, CD4+ T-cell population confirmed that the increased EGFP expression correlated with an increased HDAC11mRNA expression. Reminiscent of our prior data in APCs, the increased expression of HDAC11 in T-cells was also inversely correlated with IL-10mRNA expression. Further analyses revealed that in the absence of any stimulation or T-cell polarizing conditions, this EGFP positive population expressed significantly elevated levels of ROR-γt and IL-17 mRNA, markers specific for the TH17 subpopulation. Polarization of wild type CD4+ T-cells into functional TH17 cells was associated with reduction of HDAC11 expression, suggesting a potential role for HDAC11 in regulating T-cell function and/or activation, in particular within the TH17 subset. Further support for this regulatory role of HDAC11 has been provided by our additional findings that T-cells devoid of HDAC11 are indeed hyper-reactive in vitro and in in vivo models. 1. Villagra A, et al. Nat Immunol. 2009 Jan;10(1):92-100. 2. Gong S, et al. Nature. 2003 Oct 30;425(6961):917-25. Disclosures: No relevant conflicts of interest to declare.

Lenalidomide Consolidation Followed by Maintenance After Autologous Transplantation for Multiple Myeloma Decreases Thymic Output and Terminally Differentiated CD4 and CD8 T Cells but Increases Treg

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4046-4046 ◽  
Author(s):  
Emmanuel Clave ◽  
Corinne Douay ◽  
Tereza Coman ◽  
Marc Busson ◽  
Caroline Bompoint ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
T Cell ◽  
Conflicts Of Interest ◽  
Negative Impact ◽  
Autologous Transplantation ◽  
Immune Surveillance ◽  
Progression Free Survival ◽  
High Dose ◽  
Post Transplantation

Abstract Abstract 4046 Treatment with lenalidomide, an immunomodulatory drug, increases the time to progression in relapsed/refractory multiple myeloma. However, due to its pleiotropic effect, it is not known whether the efficacy of this drug is due only to direct tumor toxicity or also to immunomodulatory effects. We assessed in vivo the changes in T-cell reconstitution induced by lenalidomide consolidation and maintenance treatment following autologous peripheral blood stem cell transplantation (ASCT) in a cohort of multiple myeloma patients. Twenty-nine newly diagnosed myeloma patients were treated with the induction combination bortezomib plus dex followed by high dose melphalan (140–200 mg/m2) and ASCT. A first group of 11 patients were treated with lenalidomide consolidation initiated 3 to 6 months post transplantation: 25 mg/day, days 1–21 of a 28 day cycle for 2 months, followed by maintenance (10 mg/day) until disease progression. This group was compared with the 18 patients who did not receive any treatment after ASCT. Blood samples were collected at diagnosis, before the transplant and 1, 3, 6, 9, 12 and 18 months after ASCT. Thymic function was assessed by real-time PCR quantification of T cell receptor excision circles (sjTREC) and percentages and absolute counts of T lymphocyte subpopulations were determined by multicolor flow cytometry. Statistics were performed using the Log-Rank or Mann-Whitney test. The two cohorts had similar baseline characteristics and all 29 patients were in remission after ASCT. With a median follow-up of 4 years, progression-free survival (PFS) was superior with lenalidomide treatment (69% vs 36%, p=0.05) while overall survival (OS) was similar (82% vs 75%, p=0.5). Lenalidomide treatment induced a progressive decrease in sjTREC (median at 18 months, 0.25/μL vs 1.61/μL, p<0.05) and a decrease in the percentages and absolute counts of CD4+ and CD8+ CD45RA+CCR7- effector terminal T cell subpopulations (median at 18 months, 3.2/μL vs 17.6/μL, p<0.05 for CD4+CD45RA+CCR7- and 109/μL vs 345/μL, p<0.05 for CD8+CD45RA+CCR7-). Conversely, lenalidomide treated patients displayed an increase in CD4+CD25+CD127-/low Treg populations, in both percentage and absolute count (median 13% vs 8 %, p<0.05 and 48.9/μL vs 29.3/μL, p<0.05, respectively). No correlation was found with documented infections, relapse or survival. We confirm an increase in PFS with lenalidomide consolidation/maintenance following ASCT. However, our data also suggest that in myeloma patients, the effect of lenalidomide on the myeloma tumor may not be T cell mediated and this treatment may have a negative impact on the T cell immune surveillance. Disclosures: No relevant conflicts of interest to declare.

Promoting Regulation Via the Inhibition of DNAM-1 After Transplantation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 338-338
Author(s):  
Motoko Koyama ◽  
Rachel D Kuns ◽  
Stuart D Olver ◽  
Katie E Lineburg ◽  
Mary Lor ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
T Cell ◽  
Median Survival ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
Acute Gvhd ◽  
Cd4 T Cell

Abstract Abstract 338 Graft-versus-host disease (GVHD) is the major limitation of allogeneic hematopoietic bone marrow transplantation (BMT). Donor T cells play pivotal roles in GVHD and graft-versus-leukemia (GVL) effects and following BMT all T cell fractions, including regulatory T cells (Treg) express the DNAX accessory molecule-1 (DNAM-1, CD226) and T cell Immunoglobulin and ITIM domain (TIGIT) molecule. DNAM-1 is a co-stimulatory and adhesion molecule, expressed mainly by NK cells and CD8+ T cells at steady state to promote adhesion to ligand (CD155, CD112)–expressing targets and enhance cytolysis. TIGIT is a regulatory ligand expressed predominantly by Treg as steady state which competes for CD155 binding, We have analyzed the role of this pathway in GVHD and GVL. Lethally irradiated C3H/Hej (H-2k) mice were injected with bone marrow cells and T cells from MHC disparate wild-type (wt) or DNAM-1–/– C57Bl6 (H-2b) mice. Recipients of DNAM-1–/– grafts were protected from GVHD (survival 67% vs. 7%, P < .0001). We also confirmed the role of DNAM-1 in GVHD in a MHC-matched BMT model (B6 → BALB/B (H-2b)) where GVHD is directed to multiple minor histocompatibility antigens. Next we examined the donor populations expressing DNAM-1 which mediate this effect. DNAM-1 had little impact on acute GVHD severity in the B6 → bm1 BMT model where GVHD is directed against an isolated MHC class I mismatch and is CD8-dependent. In contrast, recipients of wt bone marrow and DNAM-1–/– CD4 T cells survived long-term (compared to recipients of wt CD4 T cells, survival 81% vs. 25%, P = .003) in the B6 → B6C3F1 BMT model, confirming the protection from GVHD is CD4-dependent. Donor CD4 T cell expansion and effector function (Th1 and Th17), and CD8 T cell expansion and cytotoxic function were equivalent in recipients of wt and DNAM-1–/– grafts. However the percentage and number of Treg were significantly increased in recipients of DNAM-1–/– grafts compared to those of wt grafts. The depletion of Treg from donor grafts eliminated the protection from GVHD seen in the absence of DNAM-1 signalling (median survival 16 days vs. 15.5 days, P = 0.53). Adoptive transfer experiments using FACS-sorted Treg were undertaken to compare the relative ability of B6.WT and B6.DNAM-1–/– Treg to suppress GVHD. The majority of recipients of DNAM-1–/– Treg survived beyond day 50 (median survival; day 56), demonstrating a superior ability to suppress acute GVHD relative to wt Treg where the median survival was day 36 (survival 47% vs. 0%, P = .001). These data demonstrate that donor DNAM-1 expression promotes GVHD in a CD4+ T cell-dependent manner via the inhibition of donor Foxp3+ Treg. Finally, the absence of donor DNAM-1 did not influence leukemia-specific mortality in multiple GVL models, regardless of whether the tumor expressed CD155 or not. Thus we demonstrate that the DNAM-1 pathway promotes GVHD, putatively due to competition with TIGIT on Treg, thereby inhibiting regulatory function. This provides support for therapeutic DNAM-1 inhibition to promote tolerance not only after transplant but also in relevant inflammatory based diseases characterized by T cell activation. Disclosures: No relevant conflicts of interest to declare.

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