Innate Lymphoid Cell-Derived IL-22 Regulates Epithelial Recovery From Gvhd

Abstract Abstract 339 There is little understanding of the maintenance and regeneration of epithelial tissues after allogeneic transplant. Most clinical strategies to limit epithelial damage from graft vs. host disease (GVHD) also limit post-transplant immune function. Damage to the gastrointestinal (GI) tract from GVHD is a major cause of morbidity and mortality, and damage to the thymus from pre-transplant conditioning and GVHD can impair immune reconstitution, predispose patients to infection, and increase the risk of relapse. Therefore, understanding of tissue damage and recovery could lead to strategies selectively protecting epithelial tissues, improving intestinal barrier function, and promoting immune reconstitution without worsening post-transplant immunosuppression. We have recently identified that IL-22 from recipient-derived innate lymphoid cells (ILC) is critical for promoting intestinal recovery from GVHD and for promoting thymic recovery from radiation/pre-transplant conditioning. IL-22 deficient mice demonstrated significantly reduced thymopoiesis after total body irradiation (TBI), and IL-22 deficient murine bone marrow transplant (BMT) recipients demonstrated increased GVHD mortality and intestinal histopathology, deficiency of the antimicrobial molecules Reg3γ and Reg3β, and loss of intestinal stem cells needed for epithelial recovery. The source of thymic and intestinal IL-22 was RORγ+CD3−NKp46−IL-7R+CCR6+ lymphoid-tissue-inducer-like cells. Similar to as had been observed in the thymus, intestinal ILC produced IL-22 in response to IL-23, which was upregulated after TBI (p<.05 small intestine, p<.001 large intestine). IL-22 was also upregulated in response to TBI, but not in p40-deficient mice lacking IL-23 (p<.05 small intestine, p<.01 large intestine). ILC were radioresistant, as lethal TBI led to a three-fold increase in the intestinal ILC:CD4 ratio (p<.05). Furthermore, recipient-derived ILC comprised more than 50% of intestinal lamina propria ILC three months after T cell-depleted BMT, well after donor myeloid reconstitution and after donor reconstitution of the intestinal T cell compartment as well (Figure 1). Although intestinal ILC could survive lethal TBI, they were significantly depleted by both MHC mismatched (B6BALB/c) and MHC matched (LPB6) GVHD. Similarly, GVHD led to depletion of thymic IL-22+ ILC and reduction in thymic IL-22 levels (p<.001). Thymic IL-22 was critical for maintaining thymopoiesis during GVHD, as IL-22 deficient BMT recipients demonstrated significantly greater loss of double positive (DP) thymocytes after MHC-mismatched BMT. We previously identified that IL-21 receptor (IL-21R) signaling contributes to the migration of alloreactive donor T cells to the GI tract and that IL-21R-deficent donor T cells mediate significantly reduced GI GVHD. Given the similar homing molecules involved in the migration of donor T cells to the GI tract and thymus in GVHD, we evaluated the role of IL-21 in thymic GVHD. Donor T cell IL-21R deficiency led to increased thymopoiesis and DP thymocytes (p<.001), but not in IL-22-deficient recipients. ILC evaluation indicated that this IL-22 dependency was because IL-21R-deficiencient donor T cells had a reduced capacity to eliminate thymic ILC during GVHD (Figure 2). Therefore, donor T cell IL-21 signaling was critical for the elimination of recipient thymic ILC during GVHD, and preservation of the ILC compartment allowed for the IL-22 mediated regeneration of thymopoiesis. Finally, we also found that administration of rIL-22 post-BMT could reverse the thymic damage caused by GVHD and elimination of ILC, restoring the numbers of DP thymocytes to a level similar to what was observed after T cell-depleted BMT. In summary, IL-22+ ILC are radioresistant and capable of regulating tissue-specific epithelial recovery after allogeneic BMT. However, recipient ILC are extremely sensitive to GVHD, leading to a loss of the IL-22-mediated recovery response. IL-21 blockade can prevent the elimination of recipient thymic ILC by donor T cells in GVHD, and IL-22 administration can restore the thymopoiesis that is lost in GVHD due to ILC elimination. Maintenance of epithelial function post-BMT is thus an active innate immune response requiring cooperation between both recipient stroma and recipient hematopoietic cells. Disclosures: No relevant conflicts of interest to declare.

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Donor DC Subsets Polarize Donor T-Cell Immune Responses in Allogeneic BMT.

Blood ◽

10.1182/blood.v106.11.573.573 ◽

2005 ◽

Vol 106 (11) ◽

pp. 573-573

Author(s):

Jian-Ming Li ◽

Cynthia Giver ◽

Doug McMillan ◽

Wayne Harris ◽

David L. Jaye ◽

...

Keyword(s):

Stem Cells ◽

T Cells ◽

T Cell ◽

Immune Responses ◽

Peripheral Blood ◽

Immune Reconstitution ◽

Hematopoietic Cell ◽

Post Transplant ◽

Donor T Cells ◽

Ifn Γ

Abstract Introduction: Impaired or inappropriate immune reconstitution after allogeneic bone marrow transplantation (BMT) can lead to infection, graft-versus-host disease (GvHD) and leukemia relapse. We have previously reported that BM contains two populations of dendritic cell (DC) subsets, CD11b+ DC and CD11b− DC, and that CD11b depleted donor BM promoted increased donor T-cell chimerism and increased graft-versus-leukemia (GvL) activity in C57BL/6 → B10BR transplants [BBMT, 2004, 10: 540]. To explore the mechanism by which CD11b-depletion improved allo-reactivity, we performed allogeneic hematopoietic cell transplants using defined populations of donor stem cells, DCs, and T-cells in a MHC mis-matched BMT model. Methods: We transplanted FACS purified populations of 50,000 GFP+ CD11b- DC or CD11b+ DC in combination with 5,000 FACS purified Lin- Sca-1+ c-kit+ hematopoietic stem cells (HSC) and 300,000 or 1,000,000 congenic spleen T-cells from C57BL/6 donors into C57BL/6[H-2Kb], B10BR[H-2Kk] and PL/J[H-2Ku] recipients. Proliferation of CFSE stained donor T-cells was measured at 72 hours post-transplant. FACS cytometric bead array and intracellular cytokine staining measured serum and intracellular cytokines in donor T-cells. Results: The initial proliferation and Ki-67 expression of CFSE labeled donor T-cells in allogeneic recipients were much higher than in syngeneic recipients (homeostatic proliferation). Confocal microscopy showed co-localization of donor DC subsets with donor T-cells in the recipient spleens at 3 and 10 days post-transplant. In the allogeneic transplant settings, donor T-cells co-transplanted with CD11b- DC showed increased IFN-γ synthesis at 3 and 10 days post-transplant compared to donor T-cells co-transplanted with HSC plus CD11b+ DC or HSC alone. Increased proliferation of donor T-cells led to increased donor T-cell chimerism at day 10, 30, 60, and day105 post-transplant among recipients of CD11b- DC compared to recipients of HSC alone or HSC plus CD11b+ DC (Figure 1). Transplantation of spleen T-cells and CD11b- DC did not increase GvHD, but was associated with full donor chimerism. In contrast, transplantation of allogeneic CD11b+ DC led to persistence and expansion of residual host T-cells (Figure 2), increased numbers of donor CD4+CD25++Foxp3+ T-cells, and higher serum level of IL-10 supporting early post-transplant expansion of donor T regulatory cells (Treg). Conclusions: Donor CD11b- DC promoted immune reconstitution by polarizing donor T-cells to Th1 immune responses associated with increased IFN-γ synthesis and donor T-cell proliferation, while donor CD11b+ DC suppressed immune reconstitution by inhibiting donor T-cell allogeneic immune responses. These data support a novel paradigm for the regulation of post-transplant immunity and suggest clinical methods to test the hypothesis that manipulation of the DC content of a hematopoietic cell allograft regulates post transplant immunity in the clinical setting. Figure 1. Donor Spleen Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(+)DC and spleen T-cells] Figure 1. Donor Spleen Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(+)DC and spleen T-cells] Figure 2. Host Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(-)DC and spleen T-cells] Figure 2. Host Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(-)DC and spleen T-cells]

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Post-Transplant Cyclophosphamide Ameliorates Lethal Thymic GVHD By Restoring Regulatory and Effector T Cell Homeostasis in Recipients with Prior PD-1 Blockade Therapy

Blood ◽

10.1182/blood-2018-99-111142 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 479-479

Author(s):

Shuntaro Ikegawa ◽

Yusuke Meguri ◽

Takumi Kondo ◽

Hiroyuki Sugiura ◽

Yasuhisa Sando ◽

...

Keyword(s):

Overall Survival ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Immune Reconstitution ◽

T Cell Subsets ◽

Post Transplant ◽

Gvhd Prophylaxis ◽

Donor T Cells ◽

The Impact

Abstract Allogeneic HSCT has a curative potential for patients with hematological malignancies. However, graft-versus-host disease (GVHD) remains to be a significant cause of morbidity and mortality after HSCT. Regulatory T cells (Tregs) are critical mediator for immune tolerance after HSCT and we recently reported that PD-1 plays an essential role for Treg survival (Asano et al, Blood 2017). Clinical studies suggested that PD-1 blockade prior to HSCT could be a risk of increasing severe GVHD. However, the mechanisms about GVHD induced by PD-1 blockade have largely unclear and there remains a paucity of data on appropriate GVHD prophylaxis for patients who undergo HSCT after PD-1 blockade. To address these issues, we investigated the impact of PD-1 expression on donor T cells on immune reconstitution with murine BMT models. First, lethally irradiated B6D2F1 mice were transplanted with 10 million of C57BL/6-background PD-1+/+ or PD-1-/- spleen cells with 5 million of bone marrow cells from normal C57BL/6, and GVHD scores and overall survival was monitored. Recipients receiving PD-1-/- graft developed severe GVHD resulting in a significant shorter survival than recipients receiving PD-1-/- graft (P<0.0001). We analyzed lymphocytes in spleen and thymus on day3, 7, and 14. We found that CD8 T cells in PD-1-/- group showed markedly higher Ki67 expression and CFSE-dilution until day3. Interestingly, PD-1-/- Tregs increased aggressively at day3 but it could not maintain until day14, while PD-1-/- CD8 T cells and conventional CD4 T cells (CD4 Tcons) continued to increase until day+14, resulting in the significant higher CD8/Treg ratio in PD-1-/- group (P<0.05, vs PD-1+/+ group). PD-1-/- Tregs showed significantly higher expression of Annexin V on day+7 and thymus CD4- and CD8- double-positive (DP) cells were in the extremely low levels in PD-1-/- group on day+14 (P<0.05, vs PD-1+/+ group). Thymic analysis showed that donor PD-1-/- graft-derived CD8 T cells infiltrated thymus in PD-1-/- group, suggesting reconstruction of thymic function was critically disturbed by severe GVHD. These data suggest that loss of PD-1 signaling resulted in unbalanced reconstitution of donor-derived T cell subsets as a consequence of continuous CTL expansion and increased Treg apoptosis. Next, to evaluate the impact of post-transplant cyclophosphamide (PTCy) on the abnormal reconstitution after PD-1 blockade, we administered 50mg/kg of Cy or control vehicle on day3. PTCy efficiently ameliorated GVHD in PD-1-/- group and extended overall survival by safely regulating the proliferation and apoptosis of T cell subsets. Of note, after PTCy, Tregs regained the ability of continuous proliferation in the first 2 weeks, resulting in well-balanced reconstitution of donor-derived T cell subsets. Thymic DP cells on day 14 was markedly increased in PD-1-/- group with PTCy intervention as compared to without PTCy, suggesting PTCy could rescue thymus from PD-1 blockade-related severe GVHD. Finally, to evaluate GVL activity, we performed BMT with co-infusion of P815L tumor cells on day0 and we confirmed that PTCy treatment for PD-1-/- recipients reduced the severity of GVHD with maintaining sufficient GVL effect. In summary, our data suggested three insights about the impact of PD-1 signaling on immune reconstitution. First, PD-1 inhibition influenced graft-derived T cells very differently within T cell subsets. PD-1-/- Tregs increased transiently but it was counterbalanced by accelerated apoptosis, while PD-1-/- CD4+Tcons and CD8 T cells continued the drastic expansion. Second, we found that PD-1-/- donor T cells developed severe GVHD in thymus. Few reports have concentrated on the impact of donor graft PD-1 expression to thymus after BMT and acute GVHD in thymus could lead late central immune disturbance. Third, PTCy successfully ameliorated GVHD induced by PD-1-/- donor T cells preserving GVL effect. Cell proliferation study implied that PD-1-/- graft-derived CD8 T cells might be more susceptible for PTCy because of the high-rate proliferation. In conclusion, PD-1-/- graft cause lethal thymic GVHD and PTCy successfully ameliorated it. The influence of PD-1 inhibition was different within T cell subtypes. PTCy might be appropriate GVHD prophylaxis strategy for patients who had prior usage of PD-1 blockade. Disclosures No relevant conflicts of interest to declare.

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IL-22 Administration Decreases Intestinal Gvhd Pathology, Increases Intestinal Stem Cell Recovery, and Enhances Immune Reconstitution Following Allogeneic Hematopoietic Transplantation

Blood ◽

10.1182/blood.v122.21.290.290 ◽

2013 ◽

Vol 122 (21) ◽

pp. 290-290

Author(s):

Anna M Mertelsmann ◽

Jarrod A Dudakov ◽

Enrico Velardi ◽

Guoqiang Hua ◽

Fabiana M Kreines ◽

...

Keyword(s):

T Cells ◽

Small Intestine ◽

Stem Cell ◽

T Cell ◽

Large Intestine ◽

Immune Reconstitution ◽

Hematopoietic Stem ◽

Epithelial Regeneration ◽

Reporter Mice ◽

Intestinal Pathology

Abstract Mechanisms regulating host tissue recovery from immune-mediated damage in gastrointestinal graft vs. host disease (GI GVHD) remain incompletely understood. Prophylactic strategies selectively promoting epithelial regeneration after allogeneic hematopoietic stem/progenitor cell transplantation (allo-HCT) have the potential to reduce GVHD without limiting therapeutic graft vs. leukemia/lymphoma (GVL) responses. We have previously shown that IL-22 produced by recipient-derived innate lymphoid cells (ILCs) provides a critical signal for epithelial recovery following experimental allo-HCT. IL-22-deficient recipients demonstrated increased GVHD mortality and significantly worse loss of crypt base intestinal stem cells (ISCs) during GVHD. Paradoxically, GVHD led to reduced GI IL-22 levels in wild-type (WT) recipients due to the elimination of radioresistant intestinal ILCs. We therefore sought to determine if IL-22 administration after allo-HCT could negate the effect of ILC elimination and reduce GVHD pathology without impairing GVL. We utilized a clinically modeled LP into C57BL/6 (B6) minor antigen mismatched model with T cell-depleted marrow and MACS-purified T cells transplanted into lethally irradiated mice. Recipients were treated daily with PBS or 4ug murine recombinant (r)IL-22 delivered via intraperitoneal (IP) injection starting day 7 post-HCT. This schedule was based on the results of rIL-22 pharmacokinetics tested in untransplanted mice. We found that daily IP administration with rIL-22 led to decreased GVHD pathology in recipient small intestine, large intestine, and liver three weeks post-HCT (Figure 1, p<.001). No differences were observed in skin histopathology, consistent with our previous finding that IL-22-deficient recipients demonstrated equivalent skin GVHD. Further assessment of the intestinal pathology indicated that recipients of rIL-22 had decreased intestinal crypt apoptosis in both small and large intestine (p<.01) with no difference in intestinal lymphocytic infiltration, suggesting that the decrease in GVHD was due to direct effects of IL-22 on the epithelium. Furthermore, no differences were observed in splenic T cell expansion or in GI cytokine expression, including a multiplex panel of inflammatory cytokines. To assess the effects of IL-22 administration on the ISC compartment, we performed LP into B6 allo-HCT using Lgr5-LacZ ISC reporter mice. Recipients treated with rIL-22 demonstrated increased numbers of Lgr5+ ISC three weeks post-HCT during active GVHD with no immunosuppression (Figure 2, p<.05). Preliminary evidence with Lgr5-GFP reporter mice suggested increased ISC Ki-67 staining and thus increased ISC proliferation following IL-22 administration. Small intestine qPCR after IL-22 treatment demonstrated increased expression of Reg3γ (p<.001) and Reg3β (p<.01), suggesting a potential antimicrobial benefit of IL-22 administration. However, there was no difference in Wnt3 or EGF expression, arguing that the stem cell benefit after IL-22 administration was not due to improvement in ISC niche function. Given the lack of IL-22R expression in hematopoietic cells, we hypothesized that IL-22 administration would not limit GVL. This was confirmed by monitoring luciferase+ A20 bioluminescence in B6 into BALB/c tumor challenge recipients treated with rIL-22. Finally, we have previously shown that rIL-22 administration can increase the number of double positive thymocytes post-HCT by protecting thymic epithelium from radiation injury and from GVHD. We hypothesized that this could translate into improved peripheral T cell reconstitution even during active GVHD. Indeed, FVB into BALB/c MHC-mismatched transplant with Rag2-GFP marrow and WT T cells indicated that IL-22 administration increased the development of donor marrow-derived CD4 and CD8+ thymic emigrants four weeks post-HCT (Figure 3, p<.01). In summary, we found that IL-22 administration could reduce intestinal pathology, improve ISC recovery, and promote donor marrow-derived T cell development during GVHD. Importantly, IL-22 administration did not impair GVL. These results suggest that post-transplant IL-22 administration represents a novel strategy to protect intestinal epithelium and improve immune reconstitution after allo-HCT. Disclosures: No relevant conflicts of interest to declare.

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Impact of Different T Cell Depletion Protocols on Immune Reconstitution Following Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2020-139208 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 43-44

Author(s):

Amandine Pradier ◽

Adrien Petitpas ◽

Anne-Claire Mamez ◽

Federica Giannotti ◽

Sarah Morin ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Reconstitution ◽

Cell Depletion ◽

Unrelated Donor ◽

T Cell Depletion ◽

Hematopoietic Stem ◽

Post Transplant ◽

The Impact

Introduction Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established therapeutic modality for a variety of hematological malignancies and congenital disorders. One of the major complications of the procedure is graft-versus-host-disease (GVHD) initiated by T cells co-administered with the graft. Removal of donor T cells from the graft is a widely employed and effective strategy to prevent GVHD, although its impact on post-transplant immune reconstitution might significantly affect anti-tumor and anti-infectious responses. Several approaches of T cell depletion (TCD) exist, including in vivo depletion using anti-thymocyte globulin (ATG) and/or post-transplant cyclophosphamide (PTCy) as well as in vitro manipulation of the graft. In this work, we analyzed the impact of different T cell depletion strategies on immune reconstitution after allogeneic HSCT. Methods We retrospectively analysed data from 168 patients transplanted between 2015 and 2019 at Geneva University Hospitals. In our center, several methods for TCD are being used, alone or in combination: 1) In vivo T cell depletion using ATG (ATG-Thymoglobulin 7.5 mg/kg or ATG-Fresenius 25 mg/kg); 2) in vitro partial T cell depletion (pTCD) of the graft obtained through in vitro incubation with alemtuzumab (Campath [Genzyme Corporation, Cambridge, MA]), washed before infusion and administered at day 0, followed on day +1 by an add-back of unmanipulated grafts containing about 100 × 106/kg donor T cells. The procedure is followed by donor lymphocyte infusions at incremental doses starting with 1 × 106 CD3/kg at 3 months to all patients who had received pTCD grafts with RIC in the absence of GVHD; 3) post-transplant cyclophosphamide (PTCy; 50 mg/kg) on days 3 and 4 post-HSCT. Absolute counts of CD3, CD4, CD8, CD19 and NK cells measured by flow cytometry during the first year after allogeneic HSCT were analyzed. Measures obtained from patients with mixed donor chimerism or after therapeutic DLI were excluded from the analysis. Cell numbers during time were compared using mixed-effects linear models depending on the TCD. Multivariable analysis was performed taking into account the impact of clinical factors differing between patients groups (patient's age, donor type and conditioning). Results ATG was administered to 77 (46%) patients, 15 (9%) patients received a pTCD graft and 26 (15%) patients received a combination of both ATG and pTCD graft. 24 (14%) patients were treated with PTCy and 26 (15%) patients received a T replete graft. 60% of patients had a reduced intensity conditioning (RIC). 48 (29%) patients received grafts from a sibling identical donor, 94 (56%) from a matched unrelated donor, 13 (8%) from mismatched unrelated donor and 13 (8%) received haploidentical grafts. TCD protocols had no significant impact on CD3 or CD8 T cell reconstitution during the first year post-HSCT (Figure 1). Conversely, CD4 T cells recovery was affected by the ATG/pTCD combination (coefficient ± SE: -67±28, p=0.019) when compared to the T cell replete group (Figure 1). Analysis of data censored for acute or chronic GVHD requiring treatment or relapse revealed a delay of CD4 T cell reconstitution in the ATG and/or pTCD treated groups on (ATG:-79±27, p=0.004; pTCD:-100±43, p=0.022; ATG/pTCD:-110±33, p<0.001). Interestingly, pTCD alone or in combination with ATG resulted in a better reconstitution of NK cells compared to T replete group (pTCD: 152±45, p<0.001; ATG/pTCD: 94±36, p=0.009; Figure 1). A similar effect of pTCD was also observed for B cells (pTCD: 170±48, p<.001; ATG/pTCD: 127±38, p<.001). The effect of pTCD on NK was confirmed when data were censored for GVHD and relapse (pTCD: 132±60, p=0.028; ATG/pTCD: 106±47, p=0.023) while only ATG/pTCD retained a significant impact on B cells (102±49, p=0.037). The use of PTCy did not affect T, NK or B cell reconstitution when compared to the T cell replete group. Conclusion Our results indicate that all TCD protocols with the only exception of PTCy are associated with a delayed recovery of CD4 T cells whereas pTCD of the graft, alone or in combination with ATG, significantly improves NK and B cell reconstitution. Figure 1 Disclosures No relevant conflicts of interest to declare.

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New Developments in Allotransplant Immunology

Hematology ◽

10.1182/asheducation-2003.1.350 ◽

2003 ◽

Vol 2003 (1) ◽

pp. 350-371 ◽

Cited By ~ 39

Author(s):

A. John Barrett ◽

Katayoun Rezvani ◽

Scott Solomon ◽

Anne M. Dickinson ◽

Xiao N. Wang ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Stem Cell Transplantation ◽

Cell Transplantation ◽

Immune Reconstitution ◽

Cytokine Gene ◽

Post Transplant ◽

Cytokine Milieu ◽

Cytokine Gene Polymorphisms

Abstract After allogeneic stem cell transplantation, the establishment of the donor’s immune system in an antigenically distinct recipient confers a therapeutic graft-versus-malignancy effect, but also causes graft-versus-host disease (GVHD) and protracted immune dysfunction. In the last decade, a molecular-level description of alloimmune interactions and the process of immune recovery leading to tolerance has emerged. Here, new developments in understanding alloresponses, genetic factors that modify them, and strategies to control immune reconstitution are described. In Section I, Dr. John Barrett and colleagues describe the cellular and molecular basis of the alloresponse and the mechanisms underlying the three major outcomes of engraftment, GVHD and the graft-versus-leukemia (GVL) effect. Increasing knowledge of leukemia-restricted antigens suggests ways to separate GVHD and GVL. Recent findings highlight a central role of hematopoietic-derived antigen-presenting cells in the initiation of GVHD and distinct properties of natural killer (NK) cell alloreactivity in engraftment and GVL that are of therapeutic importance. Finally, a detailed map of cellular immune recovery post-transplant is emerging which highlights the importance of post-thymic lymphocytes in determining outcome in the critical first few months following stem cell transplantation. Factors that modify immune reconstitution include immunosuppression, GVHD, the cytokine milieu and poorly-defined homeostatic mechanisms which encourage irregular T cell expansions driven by immunodominant T cell–antigen interactions. In Section II, Prof. Anne Dickinson and colleagues describe genetic polymorphisms outside the human leukocyte antigen (HLA) system that determine the nature of immune reconstitution after allogeneic stem cell transplantation (SCT) and thereby affect transplant outcomethrough GVHD, GVL, and transplant-related mortality. Polymorphisms in cytokine gene promotors and other less characterized genes affect the cytokine milieu of the recipient and the immune reactivity of the donor. Some cytokine gene polymorphisms are significantly associated with transplant outcome. Other non-HLA genes strongly affecting alloresponses code for minor histocompatibility antigens (mHA). Differences between donor and recipient mHA cause GVHD or GVL reactions or graft rejection. Both cytokine gene polymorphisms (CGP) and mHA differences resulting on donor-recipient incompatibilities can be jointly assessed in the skin explant assay as a functional way to select the most suitable donor or the best transplant approach for the recipient. In Section III, Dr. Nelson Chao describes non-pharmaceutical techniques to control immune reconstitution post-transplant. T cells stimulated by host alloantigens can be distinguished from resting T cells by the expression of a variety of activation markers (IL-2 receptor, FAS, CD69, CD71) and by an increased photosensitivity to rhodamine dyes. These differences form the basis for eliminating GVHD-reactive T cells in vitro while conserving GVL and anti-viral immunity. Other attempts to control immune reactions post-transplant include the insertion of suicide genes into the transplanted T cells for effective termination of GVHD reactions, the removal of CD62 ligand expressing cells, and the modulation of T cell reactivity by favoring Th2, Tc2 lymphocyte subset expansion. These technologies could eliminate GVHD while preserving T cell responses to leukemia and reactivating viruses.

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Protection of the Intestinal Epithelium from Conditioning with R-spondin1 Ameliorates Graft-Versus-Host Disease

Blood ◽

10.1182/blood.v112.11.66.66 ◽

2008 ◽

Vol 112 (11) ◽

pp. 66-66 ◽

Cited By ~ 2

Author(s):

Shuichiro Takashima ◽

Kazutoshi Aoyama ◽

Motoko Koyama ◽

Daigo Hashimoto ◽

Takeshi Oshima ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Graft Versus Host Disease ◽

Large Bowel ◽

Immune Reconstitution ◽

Allogeneic Bone ◽

Gi Tract ◽

Host Disease ◽

Graft Versus Host ◽

Tract Damage

Abstract Damage to the gastrointestinal (GI) tract by pretransplant conditioning regimen plays a critical role in amplifying graft-versus-host disease (GVHD). Thus protection of the GI tract from conditioning may represent a novel approach to prevent GVHD. R-Spondin1 (R-Spo1) is a novel class of soluble activator for Wnt/□-catenin signaling, and has potent and specific proliferative effects on the intestinal crypt cells; injection of R-Spo1 protects mice from chemotherapy-induced intestinal mucositis. We therefore hypothesized that administration of R-Spo1 could modulate GVHD by reducing the GI tract damage and improve outcome of allogeneic bone marrow transplantation (BMT). Lethally irradiated B6D2F1 (H-2b/d) mice were injected with 5 × 106 BM and 2 × 106 T cells from MHC-mismatched B6 (H-2b) donors on day 0. Mice were intravenously injected with 200 μg of R-Spo1 or diluent from days −3 to −1 and +1 to +3 after BMT. In vivo labeling assay of mitotic cells with BrdU demonstrated that the proliferative index, as determined by the percentages of BrdU-positive cells among crypt epithelial cells, was significantly greater in the small intestine of R-Spo1 treated mice than controls 4 days after BMT (57% ± 3% vs 48% ± 1%, P<0.05). Analysis of the mesenteric lymph nodes and spleens on day +7 demonstrated significantly reduced expansion of donor T cells in R-Spo1 treated recipients in association with reduced serum levels of IFN-□ and TNF-□ on day +7 when compared to controls (Table). GVHD was severe in allogeneic controls, with 12.5% survival by day +40, whereas 62.5% of R-Spo1-treated animals survived this period (Table). Histopathologic examination of the small and large bowel and liver showed significantly reduced GVHD pathology in R-Spo1 treated animals than in controls (Table). A flowcytometric analysis of the spleen and thymus after BMT showed that administration of R-Spo1 did not impair donor cell engraftment and T and B cell immune reconstitution. We next evaluated the impact of R-Spo1 on graft-versus-leukemia (GVL) effects. BMT was performed similarly as above with the addition of 5 × 104 host-type P815 leukemia cells (H-2d). All recipients of T cell-depleted BM died from leukemia by day +20 after BMT, while no leukemia death was observed in R-Spo1 treated allogeneic animals. Overall, R-Spo1 treatment improved outcome of allogeneic BMT by reducing GVHD, while maintaining immune reconstitution and GVL effects. Thus, administration of R-Spo1 reduces the GI tract damage and suppresses donor T cell activation and systemic GVHD, supporting a hypothesis that the GI tract plays a major role in the amplification of systemic GVHD. Brief treatment with R-Spo1 may serve as an effective adjunct to clinical regimens of GVHD prophylaxis. Pathology Scores Group Survivals on day+40 (%) Small bowel Large bowel Liver INF □ (ng/ml) TNF □ (pg/ml) TCD: T cell-depleted BMT, +T: T cell-repleted BMT, ND: not detected Data are expressed as mean ± SD. *P<0.01 vs control, **P<0.05 vs control TCD diluent 100 2.4± 0.9 3.5± 1.0 0.3± 0.3 ND ND +T diluent 12.5 8.3± 2.7 7.3± 1.9 2.0± 0.8 6.0 ± 2.4 103.7 ± 9.9 +T R-Spo1 62.5* 3.4±1.9** 3.9± 0.3** 0.8± 0.7** 2.3 ± 1.5** 55.4 ± 6.6**

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Selective Depletion of CD11b+ Dendritic Cells from Murine Allogeneic Bone Marrow Grafts Promotes a Th1 Phenotype in Donor T Cells

Blood ◽

10.1182/blood.v112.11.4610.4610 ◽

2008 ◽

Vol 112 (11) ◽

pp. 4610-4610

Author(s):

Kataryna A. Darlak ◽

Jian-Ming Li ◽

Wayne Harris ◽

Edmund K. Waller

Keyword(s):

T Cells ◽

Dendritic Cells ◽

T Cell ◽

Weight Change ◽

Intracellular Cytokine Staining ◽

Allogeneic Bone ◽

Intracellular Cytokine ◽

Post Transplant ◽

Donor T Cells ◽

Selective Depletion

Abstract Background: Allogeneic hematopoietic stem cell (HSC) transplant is a treatment used to cure patients with high risk and relapsed acute leukemia, via a graft versus leukemia (GvL) effect. In our previous studies, depletion of CD11b+ cells (containing CD11b+ dendritic cells, CD11b+ NK cells, and myeloid suppressor progenitor cells) from donor BM improved immune reconstitution and enhanced GvL effects without increased rates of GvHD in mice (Li, et al. BBMT 2004). In order to elucidate which subset of donor CD11b+ cells was responsible for this effect, we have transplanted combinations of FACS purified HSC, donor T cells, and CD11b- dendritic cells (DC) and found similar improvement in GvL activity associated with donor T cells polarized towards a Th1 phenotype (Li, et al. Blood 2007). In contrast, grafts containing FACS purified HSC, donor spleen T cells, and CD11b+ DC did not have significant GvL activity and donor T cells were polarized towards a Th2 phenotype. The objective of this study was to determine if selective depletion of CD11b+ dendritic cells by FACS would be a clinically relevant method, producing similar results as engraftment with purified populations of HSC, Cd11b- DC, and T cells. Methods: Selective CD11b+ DC depletion was achieved by FACS sorting in which cells from BM were sorted following gating of all nucleated cells with the exception of the CD11b+CD11c+Lineage- cells. The CD11b+ cells comprised ~1% of the BM. Undepleted BM was also stained and sorted using only a light scatter gate as a control for stress encountered during sorting. To study the long term effects of specific CD11b+ DC depletion, B10.BR or BA.B10 recipients were transplanted with 5×10^6 CD11b+ DC FACS-depleted or undepleted BM cells and 1×10^6 spleen T cells from C57BL/6J, Balb/C, and BA donors. Recipient mice were irradiated with 11Gy one day prior to the transplant. Recipient mice were monitored for survival, weight change, and GvHD score (based on weight change, activity, posture, fur texture, and skin condition) throughout the duration of the experiment and for chimerism of engraftment at days 30, 60, and 100 post transplant. Donor T cells were recovered from transplant recipients on days 3 and 10 post transplant and were examined for their Th1/Th2 polarization by flow cytometry after intracellular cytokine staining and ELISA of supernatants following short term culture. Results: B10.BR mice receiving undepleted BM from C57BL/6J or Balb/C mice had 100 day survivals of 60% and 40% respectively. Mice receiving CD11b+ DC depleted BM from C57BL/6J or Balb/C mice had equivalent survival at 80% and 60% survival, respectively, compared with mice receiving undepleted BM (p=ns). T cell chimerism at day 100 was over 95% donor chimerism for all mice, regardless of CD11b+ DC depletion. Differences in concentration of donor T cells in the blood were not significant between CD11b+ DC depleted and undepleted groups. The level of GvHD in recipient mice also did not differ significantly between groups. At day 3 post transplant, intracellular cytokine staining of donor T cells from mice receiving CD11b+ DC depleted BM had significantly higher levels of TNF-alpha compared with donor T cells from recipients of undepleted BM (p<0.05). Levels of IL-4, IL-10, IL-5 and IFN-gamma among donor spleen T cell population were not significantly different between undepleted and CD11b+ depleted BM recipients. Conclusions: Selective depletion of CD11b+ DC by FACS may be a clinically relevant method for increasing GvL activity without increasing GvHD. Depletion of CD11b+ DC from BM grafts polarizes donor T cells towards a Th1 phenotype, without increasing GvHD or affecting survival in recipient mice as compared with mice receiving undepleted BM grafts. The GvL effect of selective CD11b+ FACS depletion will be discussed.

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The Equilibration of Peripheral Blood and Tissue CD3+ T Cell Engraftment Is Influenced by Graft Versus Host Disease Following Reduced Intensity Conditioning Stem Cell Transplantation

Blood ◽

10.1182/blood.v116.21.2546.2546 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2546-2546

Author(s):

Victoria Harries ◽

Rachel Dickinson ◽

Venetia Bigley ◽

Matthew Collin

Keyword(s):

T Cells ◽

T Cell ◽

Graft Versus Host Disease ◽

Peripheral Blood ◽

Graft Versus Host ◽

Post Transplant ◽

Cell Engraftment ◽

Donor T Cells ◽

Patients At Risk ◽

Reduced Intensity

Abstract Abstract 2546 Alemtuzumab-containing reduced intensity transplantation regimens frequently induce a state of partial T cell chimerism in the blood of the recipient. It has been widely shown that partial T cell chimerism is associated with freedom from graft versus host disease (GVHD) and that the occurrence of GVHD is often associated with rapidly rising donor T cell engraftment. The mechanism by which this occurs remains unknown and recipient cells may be killed, out-competed for homeostatic niches or simply diluted out by expanding donor T cells. The skin, a target organ of GVHD, normally contains T cells which enter from the blood in the steady state. Studies in mice have highlighted the gate-keeping function of inflammation in allowing trafficking of host-reactive donor T cells into tissues during conversion from mixed to full donor chimerism in blood. This implies that the equilibration of donor engraftment in the blood and tissue may occur more rapidly in patients at risk for GVHD. To test this hypothesis, we set out to define the relationship between skin and blood donor T cell engraftment in patients with and without GVHD. Methods: We studied a group of 51 patients receiving fludarabine melphalan (FM) conditioning with alemtuzumab 30mg for matched related donors and 60mg for matched unrelated donors. Skin biopsies were obtained at 28 and 100 days post transplant, dermal T cells isolated by migration and chimerism assessed in sex-mismatched transplants by combined immunofluorescence/in situ hybidization for XY chromosomes. Peripheral blood myeloid (CD15+) and T cell (CD3+) chimerism was determined by short tandem repeat amplification at monthly intervals after transplantation. All patients gave consent for clinical follow up and post transplant blood and skin sampling for research purposes, according to protocols approved by the local research ethics committee of Northumberland and North Tyneside. Results: All patients achieved >95% myeloid engraftment by day 100. Median (range) T cell engraftment was variable and significantly higher after MUD transplants: 70% (9-99%) than MRD transplants: 21% (5-85%; Mann Witney p <0.05). The incidence of acute GVHD was also greater after MUD transplantation at 47% (grade I or II) compared with 11% (grade I only) for MRD recipients. Overall a positive correlation was observed between donor T cell engraftment in skin and blood at all time points (r = 0.5792; P 0.0187) and at 100 days (r = 0.6570; P 0.0281). Analysis of the data with respect to GVHD showed a further interesting finding. Patients who developed GVHD had the closest correlation between blood and skin donor engraftment, even when they were in a state of partial T cell chimerism prior to the onset of GVHD. Patients who did not develop GVHD but nonetheless eventually achieved full donor engraftment in the blood tended to show lower levels of donor T cell engraftment in the dermis at day 100. Individual examples of patients who did not develop GVHD are: blood 77%, dermis 37%; blood 77%, dermis 6%; blood 92%, dermis 25%, compared with patients who did develop GVHD: blood 55%, dermis 56%; blood 90%, dermis 75%; blood 100%, dermis 100%. Conclusion: This analysis supports the hypothesis that the equilibration of blood and tissue donor T cells is influenced by GVHD and may offer a means to predict patients at risk of GVHD after withdrawal of immunosuppression or donor lymphocyte infusion. Disclosures: No relevant conflicts of interest to declare.

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Flagellin, a TLR5 Agonist, Reduces GvHD in Allogeneic HSCT Recipients While Enhancing Anti-Viral Immunity: A Novel Therapeutic Approach

Blood ◽

10.1182/blood.v118.21.144.144 ◽

2011 ◽

Vol 118 (21) ◽

pp. 144-144

Author(s):

Mohammad S Hossain ◽

David L Jaye ◽

Brian P Pollack ◽

Alton B Farr ◽

John Roback ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Responses ◽

Cd8 T Cells ◽

Viral Immunity ◽

Hematopoietic Stem ◽

Allogeneic Hsct ◽

Post Transplant ◽

Radiation Chimeras ◽

Donor T Cells

Abstract Abstract 144 In MHC-mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT), host antigen specific donor T cells mediate acute and chronic graft-versus-host disease (GvHD). Based upon the radio-protective effects of flagellin, a TLR5 agonist protein (∼50 kDa) extracted from bacterial flagella, we reasoned that flagellin might modulate donor T cells immune responses toward host antigens, reduce GvHD, and improve immune responses to CMV infection in experimental models of allogeneic HSCT. Two 50mg/mouse i.p doses of highly purified flagellin were administered 3 hrs before irradiation and 24 hrs after allo-HSCT in H-2b ^ CB6F1 and H-2k ^ B6 models. GvHD scores were obtained with weekly clinical examination and with histological scoring of intestine, colon, liver and skin at necropsy. Flagellin treatment successfully protected allo-HSCT recipients from acute and chronic GvHDs after transplantation of 5×106 splenocytes and 5×106 T cell depleted (TCD) BM, and significantly increased survival compared to PBS-treated control recipients. Reduced acute GvHD was associated with significant reduction of a) early post-transplant proliferation of donor CD4+ and CD8+ T cells measured by Ki67 and CFSE staining, b) fewer CD62L+, CD69+, CD25+, ICOS-1+ and PD-1+ donor CD4+ and CD8+ T cells compared with the PBS-treated control recipients. Decreased numbers of activated and proliferating donor T cells were associated with significantly reduced pro-inflammatory serum IFN-g, TNF-a, and IL-6 on days 4–10 post transplant in flagellin-treated recipients compared with the PBS-treated recipients. Interestingly, both flagellin-treated recipients and PBS-treated recipients had over 99% donor T cell chimerism at 2 months post transplant. Moreover, MCMV infection on 100+ days post-transplant flagellin-treated mice significantly enhanced anti-viral immunity, including more donor MCMV-peptide-tetramer+ CD8+ T cells in the blood (p<0.05), and less MCMV in the liver on day 10 post infection (p<0.02) compared with the PBS-treated control recipients. Overall immune reconstitution after flagellin-treatment was robust and associated with larger numbers of CD4+CD25+foxp3+ regulatory T cells in the thymus. To further define the role of flagellin-TLR5 agonistic interactions in the reduction of GvHD, we next generated B6 ^ TLR5 KO (KO) and KOB^6 radiation chimeras by transplanting 10 × 106 BM cells from wild-type (WT) B6 or TLR5 KO donors into the congenic CD45.1+ B6 or KO recipients conditioned with 11Gy (5.5Gyx2) TBI. The radiation chimeras were irradiated again with 9.0Gy (4.5Gy × 2) on 60 days after the first transplant and transplanted with 3 × 106 splenocytes and 5 × 106 TCD BM from H-2K congenic donors. Two 50mg doses of flagellin were administered 3 hrs before irradiation and 24 hrs after HSCT. All flagellin-treated B6 ^ B6 radiation chimeras survived with only 12% weight-loss by 80 days post transplant compared with 50% survival among recipients of flagellin-treated B6 ^ KO and 40% survival among KO ^ B6 radiation chimeras. All flagellin-treated KO^ KO and PBS-treated radiation chimeras died within 65 days post transplant. These data suggested that interaction of flagellin with the TLR5 expressing host gut epithelium and donor hematopoietic cells are both required for the maximum protective effect of this TLR5 agonist on GvHD in allogeneic HSCT recipients. Together our data demonstrate that peritransplant administration of flagellin effectively controls acute and chronic GvHD while preserving enhanced post-transplant donor anti-opportunistic immunity. Since flagellin has been found to be safe for use in humans as vaccine adjuvant in a number of clinical trials, the clinical use of flagellin in the setting of allogeneic HSCT is of interest. Disclosures: No relevant conflicts of interest to declare.

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Influence of Graft Versus-Host Disease Prophylaxis Regimen On T-Cell Repertoire Diversity Following Reduced-Intensity HLA-Matched Unrelated Donor Allogeneic Hematopoietic Stem Cell Transplantation.

Blood ◽

10.1182/blood.v120.21.3054.3054 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3054-3054 ◽

Cited By ~ 1

Author(s):

Rachel B. Salit ◽

Frances T. Hakim ◽

Michael R. Bishop ◽

Thea M. Friedman ◽

Robert Korngold ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Reconstitution ◽

Unrelated Donor ◽

Matched Unrelated Donor ◽

Cell Repertoire ◽

Post Transplant ◽

Gvhd Prophylaxis ◽

Repertoire Diversity ◽

Reduced Intensity

Abstract Abstract 3054 Background: A clearly superior graft-versus-host disease (GVHD) prophylaxis regimen has not been established for patients undergoing reduced intensity allogeneic hematopoetic stem cell transplantation (HSCT) from matched unrelated donors (URD). Encouraging results have been reported with both the combination of alemtuzumab and cyclosporine (AC) and the regimen of tacrolimus, methotrexate, and sirolimus (TMS) in the URD setting. These two regimens work by biologically distinct mechanisms and may have markedly different effects on immune reconstitution. T-cell receptor (TCR) spectratyping analysis, which provides information on antigen receptor diversity, is a valuable method for monitoring post-transplant immune reconstitution. As part of a randomized pilot study, we prospectively assessed the effects of AC vs. TMS on TCR Vb repertoire diversity in patients undergoing reduced intensity HLA-matched unrelated donor transplantation. Methods: Twenty patients (median age 53 yrs; range 24–70 yrs) with hematologic malignancies received reduced intensity conditioning (fludarabine 30 mg/m2/day and cyclophosphamide 1200 mg/m2/day IV Day -6 to -3) followed by a 10/10 HLA-matched unrelated donor T-cell replete mobilized peripheral blood allograft. Patients were randomized to receive either: AC (n=10): alemtuzumab 20 mg/day IV over 8 hours Days -8 to -4 and cyclosporine starting at Day -1 with a 10% per week taper starting at Day +100 or TMS (n=10): tacrolimus and sirolimus starting at Day -3 with a 33% taper at Day +63 and Day +119 and methotrexate 5 mg/m2 IV, Days +1, +3, +6, and +11. Blood samples were collected from the donor and patient at baseline and the patient at 1, 3, 6 and 12 months post-transplant for TCR spectratyping analysis. All comparisons are based on an exact Wilcoxon rank sum test; p values < 0.01 were significant because of multiple comparisons. Results: Patients on the AC arm had significantly fewer T-cells on Day +14 compared with the TMS arm (median CD3+ = 1 cells/μl vs 356 cells/μl; CD4+ = 0 cells/μl vs 243 cells/μl; CD8+ = 0 cells/μl vs. 59 cells/μl; each p<0.0001); there was less disparity at Day +28 (median CD3+ = 45 cells/μl vs. 398 cells/μl; CD4+ = 36 cells/μl vs. 218 cells/μl; CD8+= 5 cells/μl vs 152 cells/μl; each p 0.002). By Day +100, lymphocyte recovery was not appreciably different between the two arms (median CD3+ = 242 cells/μl vs. 445 cells/μl (p = 0.095): CD4+ = 106 cells/μl vs. 212 cells/μl (p=0.28); CD8+ = 72 cells/μl vs. 135 cells/μl (p = 0.03). NK-cell recovery was slightly less in the AC vs. TMS arm at Day +14 (median NK = 27 cells/μl vs. 70 cells/μl; p = 0.01) and at Day +28 (median NK = 29 cells/μl vs. 150 cells/μl; p=0.02). There was no difference by Day +100 (median NK = 124 cells/μl vs. 88 cells/μl; p=0.31). B-cell reconstitution was negligible in both arms through Day +100. Assessment of CD4+ TCR Vb repertoire diversity by spectratyping demonstrated significantly lower diversity in patients receiving AC at 1 (p = 0.0003), 3 (p = 0.0003) and 6 (p=0.003) months post transplant compared with patients receiving TMS. CD8+ TCR spectratyping similarly revealed significantly reduced diversity in the AC arm at 3 (p = 0.001) and at 6 months (p = 0.003), and a trend toward significance at 12 months (p = 0.07). On each of the 2 arms, 2 of 10 patients developed acute Grade II-IV GVHD. Of the 5 patients on the AC arm who were seropositive for CMV, all 5 reactivated CMV by PCR within the first 60 days and reactivated 2–5 times in the first year. In contrast, only 3 of 5 seropositive patients reactivated CMV on the TMS arm and only one reactivated in the first 60 days. Conclusions: Two factors may have contributed to the loss of repertoire diversity in the AC arm. First, the alemtuzumab regimen may have severely depleted the infused donor T-cells. Second, stimulation by reactivating virus may have induced expansion of CMV-specific memory and effector T-cells, resulting in a skewed and oligoclonal T-cell repertoire. Especially in CD8+ T-cells, CMV has been shown to produce significant oligoclonal expansion (including CD4+: CD8+ ratio inversion). The loss of T-cell numbers and repertoire may in turn have contributed to the prevalence of early CMV reactivation. Thus, despite the similarities in frequency of acute GVHD in this small sample, it appears that these two commonly used GVHD prophylaxis regimens have very different effects on post-transplant immune reconstitution in the first 6 months after allogeneic HSCT. Disclosures: No relevant conflicts of interest to declare.

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