The Anti-CD25 Antibody Daclizumab Delays Treg Reconstitution, Promotes CD4 Memory, and Does Not Prevent Acute or Chronic Gvhd After Allogeneic Stem Cell Transplantation

Abstract Abstract 4195 Background: Daclizumab, a humanized monoclonal antibody, binds CD25 and blocks formation of the high affinity IL-2 receptor on T cells. A multi-center, randomized, double-blind clinical trial using daclizumab to perturb IL-2 signaling as a way of reducing T cell mediated graft versus host disease (GVHD) after allogeneic unrelated bone marrow transplantation (BMT) was completed 18 years ago. We report long term outcomes and biological correlates. Methods and Patients: Between April, 1993 and December, 1994, 209 adult or pediatric patients receiving marrow from an unrelated donor for hematologic malignancies or severe aplastic anemia at 12 sites in Europe and North America were randomized to one of three arms: 5 weekly doses of placebo (arm A, n=64); 0.3 mg/kg daclizumab (arm B, n=69); or 1.2 mg/kg daclizumab (arm C, n=76) to a maximum of 100 mg beginning on the day before BMT. Conditioning included total body irradiation (TBI) (1200–1440 cGy). All patients received methotrexate (15 mg/m2 day 1; 10 mg/m2 days 3, 6, 11) plus cyclosporine for at least 180 days. The study was designed to provide 80% power to detect a reduction in the incidence of acute GVHD (grade II-IV, requiring treatment with corticosteroids to day +100) from 80% to 55%. Randomization was stratified by donor HLA (matched vs. mismatched) and age (<20 vs. >=20). Arms were well balanced for HLA matching, age, disease risk, TBI dose, and diagnosis. Diagnoses were 31 ALL, 30 AML, 118 CML, 16 MDS, and 14 other. Median age was 31 years (range 1–54); 61% were male; 45% had high risk disease (14% AML with active disease or beyond 2nd remission, 20% CML beyond first chronic phase); 29% had a HLA-A, -B or -DR mismatched donor. T cells from a subset of patients (n=107) were collected at days 11–35, days 36–80, and days 81–100 and analyzed by flow cytometry for expression of total CD25, daclizumab binding, and free CD25 binding sites. Samples from arm A and arm C, including those from 1 year long term follow up (LTFU) were also evaluated for T cell phenotype. Results: The incidence of grade II-IV acute GVHD for arms A, B, and C were 34%, 42%, and 45%, and results did not differ between arm A vs. arm B (p=0.60) or arm C (p=0.38). Since other clinical outcomes did not differ significantly between arm B and arm C, the two daclizumab dose arms were combined for post-hoc exploratory analysis. There was a suggestion that the daclizumab arms showed decreased risk of relapse (HR 0.57, 95% CI: 0.32–1.00, p=0.06) and increased risk of chronic GVHD (HR 1.49, 95% CI: 0.96–2.31, p=0.07) compared to the placebo arm. Daclizumab did not increase OS (HR 0.89, 95% CI: 0.61–1.29, p=0.54) compared to placebo, and there was no interaction between disease risk and OS. Daclizumab administration reduced the total numbers of T cells expressing CD25 at days 11–35 (arm A=28% vs. arm B=16%, p<0.0001; or arm C=18%, p=0.0002); at days 36–80 (arm A=26% vs. arm B=19%, p=0.03; or arm C=19%, p=0.03); figures were equivalent at days 81–101. Daclizumab was bound to CD25 in vivo, at days 11–35 (arm A=3% vs. arm B=74%, p<0.0001; or arm C=83%, p<0.0001) and persisted at days 81–101 (arm A=4% vs. arm B=17%, p=0.05; or arm C=39%, p<0.0001). Daclizumab administration decreased the numbers of cells with free CD25 binding sites at days 11–35 (arm A=45% vs. arm B=7%, p<0.0001; or arm C=3%, p<0.0001); at days 36–80 (arm A=49% vs. arm B=25%, p<0.0001; or arm C=11%, p<0.0001); and was equivalent at days 81–101. Available samples from arm A (n=18) and arm C (n=40) were tested for Treg (CD4+ CD127- CD25+ FOXP3+) and central memory (CD4+ CD45RA- CCR7+) phenotype. Compared to placebo (arm A), daclizumab administration (arm C) decreased the proportion of CD4 cells that were Tregs at days 11–35 (12% arm A vs. 7% arm C; p=0.008), but not at days 81–101 and LTFU. Daclizumab increased the proportion of CD4 cells exhibiting central memory phenotype at LTFU (10% arm A vs. 21% arm C, p=0.02). Conclusion: This randomized phase II/III study shows that daclizumab does not prevent GVHD. There was suggestion for increased chronic GVHD and decreased relapse. Daclizumab delayed Treg reconstitution while increasing CD4 central memory at LTFU. Based on these results, further trials should test whether anti-CD25 therapy can promote anti-tumor immunity by impairing Treg reconstitution after transplant, in the appropriate clinical setting. Disclosures: Off Label Use: Daclizumab administration following hematopoietic cell transplantation. Walker:Baxter Corporation: Research Funding. Light:Bristol Myers Squibb: Employment.

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Functionally Altered GPI-Anchor Negative Treg Following Alemtuzumab-Based T-Cell Depletion Are Associated with Acute Gvhd.

Blood ◽

10.1182/blood.v120.21.3059.3059 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3059-3059

Author(s):

Eva M Wagner ◽

Lukas A Schaefer ◽

Tobias Bopp ◽

Matthias Theobald ◽

Wolfgang Herr ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Cell Depletion ◽

Gpi Anchor ◽

Activation Markers ◽

T Cell Depletion ◽

Hematopoietic Stem

Abstract Abstract 3059 Introduction: The monoclonal anti-CD52antibody Alemtuzumab is frequently used for T-cell depletion (TCD) in the context of allogeneic hematopoietic stem cell transplantation (HSCT) to prevent graft versus host disease (GVHD). We previously demonstrated the long term persistence of functionally impaired glycosylphosphatidylinositol (GPI)-anchor negative effector T-cells in patients receiving high dose (100mg) Alemtuzumab in combination with a dose reduced conditioning regimen (Fludarabin + Melpahlan) (Meyer, Wagner et al. BMT 2010). Despite of Alemtuzumab-mediated TCD, half of our patients developed acute GVHD. Since regulatory T cells (Treg) play a major role for controlling GVHD, we asked whether GPI-anchor negative Treg are present in patients with or without GVHD. Methods: We analyzed peripheral blood samples of 12 patients with acute GVHD (aGVHD), 7 patients with chronic GVHD (cGVHD), and 10 patients who never developed GVHD after Alemtuzumab-mediated TCD. To analyze Treg-subsets, we stained for CD3, CD4, CD25, CD127, FoxP3, CD52 as well as for the activation-markers GARP, HLA-DR and CD45RA. Treg were identified as CD3+CD4+CD25+CD127- or CD3+CD4+CD25+FoxP3+ cells and subdivided according to their CD52-expression. We used FLAER staining to confirm that the loss of CD52 on Treg resulted from the loss of the GPI-anchors themselves. We were able to study Treg subpopulations in the time course of patients who recovered from acute GVHD in comparison to patients with persisting late acute GVHD. In individual patients, we isolated GPI-anchor positive and negative Treg by FACS-Sort, expanded them and performed Treg suppression assays. Results: GPI-anchor negative Treg were observed in all patients, independent of the development of GVHD. However, the frequency of GPI-anchor negative Treg varied considerably between patients with acute GvHD and those with chronic GVHD or without GvHD. The percentage of GPI-anchor negative Treg was significantly elevated in patients with aGVHD: median 80.35% (range 56,2–96,8%) in comparison to 17,4% (range 0–57,8%) in patients with cGVHD or without GVHD. Activated Treg were almost exclusively detected among GPI-anchor positive Treg-subpopulation. Patients who resolved from aGVHD restored GPI-anchor positive Treg and the amount of activated Treg rose. The percentage of GPI-anchor negative Treg populations remained high in patients with ongoing aGVHD. In addition, these patients had no GARP-positive activated Treg even under long term immunosuppressive treatment. Preliminary experiments with sorted and expanded Treg populations suggest that GPI-anchor negative Treg were unable to suppress T-cell proliferation upon IL-2 stimulation. Summary: We demonstrate for the first time the reconstitution of GPI-anchor negative Treg in patients following Alemtuzumab-mediated TCD. These T cells were functionally altered and were less likely to exhibit an activated phenotype in vivo. Ongoing acute GVHD was associated with high percentages of GPI-negative Treg suggesting that their functional alteration might play a role in aGVHD pathophysiology. This is in line with the finding that only in patients who resolved aGVHD, the frequency of GPI-anchor positive Treg increased significantly. Further functional analyses are ongoing to estimate the cellular consequence of missing GPI-anchored proteins. In addition, correlating the reconstitution of GPI-anchor negative T-cell populations with further clinical events is ongoing. Disclosures: No relevant conflicts of interest to declare.

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Selective Depletion of T Cell Alloresponses Using a Photodepletion Strategy Preferentially Targets CD4+ T Cells.

Blood ◽

10.1182/blood.v116.21.1467.1467 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1467-1467

Author(s):

Zachariah A. McIver ◽

Andrew Grim ◽

Nicolas Naguib ◽

Hahn Khuu ◽

Minoo Battiwalla ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

T Cell ◽

Nk Cells ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Central Memory ◽

Viral Reactivation ◽

Post Transplant ◽

Selective Depletion

Abstract Abstract 1467 P-glycoprotein (Pgp) is the product of the multidrug-resistance-1 (MDR1) gene and actively transports various molecules across the extracellular membrane. Previous studies demonstrated that activated lymphocytes decrease Pgp activity and preferentially retain the photosensitizing agent 4, 5-dibromorhodamine 123 (TH9402, Kiadis Pharma, NL). We evaluated a photodepletion technique to achieve selective depletion (SD) of graft-versus-host disease (GVHD) alloreacting T cells in 24 HLA-identical sibling stem cell transplants. Donor lymphocytes were activated by 72 hr exposure with irradiated in-vitro expanded recipient T lymphocytes and pulsed with TH9402. Alloactivated T cells preferentially retaining the photosensitizer were eliminated by light exposure. The transfused cell products were then analyzed for T cell subset frequency. After SD preferential CD4+ T cell depletion occurred with an inversion of the CD4+/CD8+ ratio. Within the CD4+ compartment a significant depletion of naïve (CD27+ CD45RO-), central memory (CD27+ CD45RO+), and effector (CD27-CD45RO+) populations was noted. Conversely, CD8+ naïve and effector subsets was relatively conserved with depletion occurring predominantly in the central memory population. Additionally, an 80% reduction in B cells occurred, with a 60% reduction of cytotoxic NK cells (CD56+CD16+) and a relative expansion of regulatory NK cells (CD56+CD16-). We compared outcomes of 24 SD transplants with 34 patients receiving a T-cell depleted transplant. All patients with hematological malignancies were conditioned with fludarabine, cyclophosphamide, and total body irradiation and received a CD34-selected stem cell allograft from an HLA identical sibling. SD recipients also received 5×106/kg SD donor T cells. Low-dose cyclosporine was used as the only post-transplant immunosuppression. Median follow up was 14.5 months. The probability of severe acute GvHD (grade III-IV, 13%) and relapse (25%) was low for all patients. On day 100 post-transplant SD transplant recipients had lower absolute CD4+ counts, and increased rates of CMV reactivation requiring treatment (median 2 vs 1 reactivations within 100 days, p<0.01), and more chronic GvHD (70% vs 31%, p=0.04). Previous studies have shown that Pgp efflux of rhodamine-123 in quiescent T cells varied between subsets, with a preferential retention occurring in the CD4+ and central memory compartments (Br J Haematol. 1998 Jun;101(4):722-7). Our data is in accordance with these observations. In conclusion, while SD appeared to eliminate alloactivated T cells resulting in low frequencies of severe acute GVHD, differences in Pgp activity and dye retention led to the preferential non-specific elimination of CD4+ and central memory T cells which may have contributed to greater viral reactivation and chronic GVHD. Disclosures: No relevant conflicts of interest to declare.

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T-Cell Depleted HLA-Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation (haplo-HSCT) Followed By Donor Lymphocyte Infusion with T Cells Transduced with the Inducible Caspase 9 (iC9) Suicide Gene in Children with Hematological Malignancies

Blood ◽

10.1182/blood.v128.22.4683.4683 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4683-4683 ◽

Cited By ~ 1

Author(s):

Barbarella Lucarelli ◽

Alice Bertaina ◽

Pietro Merli ◽

Concetta Quintarelli ◽

Daniela Pende ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Phase I ◽

Median Time ◽

Cumulative Incidence ◽

Graft Failure ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Suicide Gene ◽

Grade Ii

Abstract Background: Haplo-HSCT after depletion of α/β T and B cells is a suitable and effective option for those children with acute leukemia (AL) who need an allograft and lacking an immediately available HLA-identical donor. With this approach, recipients can benefit immediately after transplantation from the anti-leukemia effect mediated by donor natural killer (NK) and γd T cells, which can also protect against infections. A further improvement of the results achievable with this platform could achieved with a faster adaptive T-cell immunity recovery, which play a key role to augment the graft-versus-leukemia effect and the capacity to fight infections. In light of these considerations, we designed a phase I/II trial aimed at testing the safety and efficacy of post-transplant infusion of donor-derived T cells transduced with the new iC9 suicide gene (BPX-501) in children with either malignant or non-malignant disorders (NCT02065869). Remarkably, after the activation and transduction with the retroviral iC9 construct, BPX501 cells switch the phenotype towards a preferential CD45RO pattern. Patients and methods: The phase I portion of the trial consisted of a classical 3+3 design with 3 cohorts, receiving escalating doses of BPX-501 cells of 2.5x105, 5x105, and 1x106 cells/kg, respectively. Patients included in the phase II portion were planned to receive the recommended dose identified during the phase I part of the study.Enrollment of patients started in December 2014; so far, 25 patients with AL in morphological complete remission (CR) have been enrolled. Twenty patients had acute lymphoblastic leukemia (ALL) and 5 acute myeloid leukemia (AML). Details on patient, donor and transplant characteristics are reported in table 1. All patients transplanted in CR1 had either poor cytogenetic/molecular characteristics or high levels of minimal residual disease at the end of induction therapy, both factors predicting a high relapse rate. All patients were given a fully myeloablative conditioning regimen (table 1). Before haplo-HSCT, children received rabbit anti-thymocyte globulin (ATG NEOVII, 12 mg/Kg over 3 days, from day -4 to day -2) to prevent both graft-versus-host disease (GvHD) and graft failure, and Rituximab (200 mg/ m2 on day -1) to prevent EBV-related lymphoproliferative disorders. No post-transplantation GvHD prophylaxis was administered. Results: All patients engrafted and no secondary graft failure was recorded. Median time to neutrophil and platelet recovery was 18 days (range 10-22) and 11 days (range 9-13), respectively. Once documented the engraftment of donor cells, BPX-501 T lymphocytes were infused at a median time of 17 days (range 13-52) after the allograft. Two patients were enrolled in the phase I portion of the study; one each received 2.5x105 and 1x106 cells/kg. The remaining 23 children were treated in the phase II, where the recommended dose was 1x106 cells/kg. However, since we did not observe any acute GvHD requiring the infusion of the dimerizing agent (Rimiducid/AP1903) activating iC9 gene in the first 15 children receiving 1x106 cells/kg, we decided to emend the protocol to further increase the BPX501 cell dose infused to 2 and 4x106 cells/kg. Thus, the last 6 patients were enrolled in these 2 last dose levels (3 patients each). Six and 3 patients developed grade II-IV acute and chronic GvHD, respectively. In one child, given 4x106 cells/kg, we infused rimiducid for steroid-resistant grade II skin acute GvHD, with complete resolution of the disease in 24 hours. The cumulative incidence of grade II-III acute and chronic GvHD are shown in figure 1A and B, respectively. Median follow-up of these 25 children is 8 months (range 1-19 months). One of them died due to chronic GvHD-associated bronchiolitis obliterans and one child with ALL transplanted in CR2 relapsed; the cumulative incidence of non-relapse mortality and leukemia recurrence are shown in figure 1C. The probability of disease-free survival at 15 months is 87% (figure 1D). Once infused, BPX501 cells expanded and persisted over time in both peripheral blood and bone marrow. Conclusion: Overall, these data indicate that the infusion of BPX-501 cells in children with AL given selectively manipulated haplo-HSCT results in low non-relapse mortality and chronic GvHD. Although the median observation time is still limited, the cumulative incidence of disease recurrence is promising. Table 1 Table 1. Figure 1 Figure 1. Disclosures Stanson: Bellicum pharmaceuticals: Employment. Moseley:Bellicum Pharmaceuticals: Employment, Membership on an entity's Board of Directors or advisory committees.

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Donor APCs Promote Gvhd in MHC-Mismatched Transplants by Indirectly Presenting Host Minor Histocompatibility Antigens.

Blood ◽

10.1182/blood.v114.22.689.689 ◽

2009 ◽

Vol 114 (22) ◽

pp. 689-689

Author(s):

Xiaojian Wang ◽

Catherine Martone ◽

Anthony Demetris ◽

Jennifer McNiff ◽

Warren D. Shlomchik

Keyword(s):

T Cells ◽

T Cell ◽

Acute Gvhd ◽

Late Onset ◽

Chronic Gvhd ◽

Organ Distribution ◽

Cd4 Cells ◽

Histocompatibility Antigens ◽

Minor Histocompatibility Antigens ◽

Ifn Γ

Abstract Abstract 689 In MHC-mismatched allogeneic bone marrow/stem cell transplantation (alloBMT), T cells that at least in-part recognize the allogeneic MHC are likely the dominant mediators of acute GVHD. This would explain why far fewer T cells induce acute GVHD in MHC-mismatched as opposed to MHC-matched alloBMT. However, despite this difference, in human recipients of haploidentical allografts, the organ distribution and histologic appearance of GVHD, especially chronic GVHD, are similar. Moreover, late-onset GVHD in MHC-mismatched alloBMT occurs when recipient antigen presenting cells (APCs) have been replaced by donor APCs. We therefore investigated how indirect presentation of host minor histocompatibility antigens (miHAs) by donor APCs contributes to GVHD. To test this, we employed the MHC/miHA mismatched B6 (H-2b) (right arrow) BALB/c (H-2d) strain pairing. We compared GVHD in irradiated BALB/c mice that were reconstituted with B6 CD4 cells and either B6 BM or B6 MHCII-/- BM. We reasoned that if BALB/c miHAs presented by donor B6 APCs were important, GVHD would be reduced in recipients of MHCII-/- BM. As measured by weight loss and survival, this was indeed the case. However, it was possible that receiving MHCII-/- donor BM reduced GVHD for reasons unrelated to the presentation of BALB/c miHAs. To address this we compared GVHD in irradiated B6.C (H-2d) recipients of B6 CD4 cells and either B6 or B6 MHCII-/- BM. This strain pairing shares the same MHC mismatch as does the B6(right arrow)BALB/c model, but lacks miHAs except those encoded by the congenic H-2d region. In contrast to the prior experiments, B6.C recipients of MHCII-/- or wild type BM developed similar GVHD. To further define indirect-presentation of miHAs in MHC/miHA-mismatched alloBMT, we used B6 Marilyn CD4+ T cell receptor transgenic T cells that recognize an IAb-restricted peptide derived from the male DBY protein. Male or female BALB/c mice were irradiated and reconstituted with female B6 BM and female polyclonal B6 CD4 cells along with graded numbers of Marilyn T cells. At day 7 and 14 post transplant Marilyn cells expanded at least 1000-fold greater in male than in female recipients. Marilyn T cell expansion was similar when male antigen was restricted to hematopoietic or nonhematopoietic cells. There was little expansion of Marilyn cells in male BALB/c mice if donor BM was MHCII-/-, confirming that expansion of Marilyn T cells depended on donor APCs presenting DBY. Indirectly primed Marilyn cells were functional as measured by IFN-γ production after restimulation by the DBY peptide in vitro. As we saw reduced GVHD in the B6 (right arrow) BALB/c model in recipients of MHCII-/- BM, we reasoned we should be able to detect polyclonal CD4 cells responding to host miHA presented by donor APCs. That was the case as we found an increase in DBY-reactive polyclonal CD4 cells by ELISPOT in male recipients as compared to female recipients at day 7 (1.5 fold for IFN-γ and TNF-αa). This difference was lost when donor BM was MHCII-/-. In summary, indirect presentation of host miHAs by donor APCs in MHC-mismatched alloBMT is surprisingly efficient and alloreactive CD4 cells that target host miHAs presented by donor APCs contribute to GVHD in MHC/miHA-disparate alloBMT. The generation of T cells that target host miHAs presented by donor APCs allows GVHD to persist even when host APCs that prime T cells that recognize the allogeneic MHC have been eradicated. This provides a mechanistic explanation for why late onset GVHD, including chronic GVHD, in MHC-mismatched alloBMT resembles that in MHC-matched alloBMT as both may target host miHAs indirectly presented by donor-derived APCs. These data also provide further rationale for targeting donor-derived APCs as a method for preventing and treating GVHD. Disclosures: No relevant conflicts of interest to declare.

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Impact of Immune Reconstitution (IR) and Graft-Versus-Host Disease (GvHD) on Clinical Outcomes after Treatment with Donor T Cells Transduced to Express the Herpes Simplex Virus Thymidine-Kinase Suicide Gene (TK cells) in Acute Leukemia Patients Undergoing Haploidentical Hematopoietic Stem Cell Transplantation (HSCT)

Blood ◽

10.1182/blood.v128.22.4599.4599 ◽

2016 ◽

Vol 128 (22) ◽

pp. 4599-4599 ◽

Cited By ~ 1

Author(s):

Fabio Ciceri ◽

Chiara Bonini ◽

Arnon Nagler ◽

Evangelia Yannaki ◽

Maria Teresa Lupo Stanghellini ◽

...

Keyword(s):

Risk Factors ◽

T Cells ◽

T Cell ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Suicide Gene ◽

Baseline Risk ◽

Hematopoietic Stem ◽

Cell Dose ◽

Grade Ii

Abstract Background: Haploidentical HSCT is a readily available platform for most patients lacking an HLA-matched donor, but the T-cell depleted (TCD) approach without any post-transplant donor cell therapy is impaired by high non-relapse mortality (NRM) due to slow IR, while the T-cell replete (TCR) approach followed by cyclophosphamide and immunosuppressive therapy is hampered by high chronic GvHD and relapse incidence (RI) Methods: The impactof IR and TK-cell dose on outcomes was assessed in 45 patients with several hematological malignancies treated with 1 to 4 monthly TK infusions (0.1-1.0x107/Kg, 21-49 days after haploidentical HSCT) in a phase 2 trial (n=30; Lancet Oncol 2009; 10: 489) and in the experimental arm of an ongoing phase 3 trial (n=15; NCT00914628). Median follow-up time for TK-treated patients was 3.7 years (interquartile range [IQR], 1.5-8.5). Outcome measures included 1-year NRM, overall survival (OS), leukemia-free survival (LFS), RI and GvHD. Hazard ratios (HR) and odds ratios (OR) were derived by regression models adjusted for baseline risk factors. IR (T cells ≥ 100/µL) was modelled as a time-dependent covariate. These pooled data were the basis for the positive opinion for conditional marketing authorization recently granted for TK cells (www.ema.europe.eu/EPAR/Zalmoxis) Results: IR was achieved by 34 patients (76%) after a median of two TK infusions (IQR, 1-2), a median cumulative cell dose of 1.3x107/kg (1.0-2.4) and a median time from HSCT of 83 days (65-108). IR was not influenced by baseline risk factors or TK-cell doses and was associated with decreased NRM (12% vs 75%; p<0.0001) and improved LFS (HR=0.20; p=0.005) and OS (HR=0.08; p<0.0001). Grade II-IV acute GvHD (35%; grade III-IV: 7%) was unrelated to TK-cell dose and occurred nearly exclusively in IR (OR=7.0; p=0.07) and female patients (OR=9.7; p=0.007). Only one patient had de novo chronic GvHD. All GvHD events fully resolved (median, 14 days; 10-27) after suicide-gene induction with ganciclovir (median, 15 days; 13-16). Cumulative RI (31%) did not differ according to IR, while it was inversely related to TK-cell dose, with decreased relapse rates (60%, 33% and 0%) observed with increasing cell doses (<1.0, 1.0-2.4 and >2.4x107, respectively; p=0.004). TK patients had significant outcomes in OS (51%), NRM (20%) and chronic GvHD (6%). Importantly, TK patients with grade II-IV acute GvHD treated with ganciclovir experienced high OS rates (67%), thus confirming the ability of TK machinery to selectively targeting GvHD effector cells, while sparing a wide repertoire protective against infections and leukemia recurrence Conclusions: TK-cell treatment is characterized by early IR and full GvHD control that translate in improved NRM and OS and by dose-related antileukemic effects, with overall outcomes comparing very favorably with those of current approaches to haploidentical HSCT Disclosures Ciceri: MolMed SpA: Consultancy. Bonini:TxCell: Membership on an entity's Board of Directors or advisory committees; Molmed SpA: Consultancy. Colombi:MolMed: Employment. Lambiase:MolMed: Employment. Bordignon:MolMed SpA: Employment.

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P01.13 MERTK signaling is critical for T cell proliferation and memory

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-itoc7.26 ◽

2020 ◽

Vol 8 (Suppl 2) ◽

pp. A14.2-A15

Author(s):

RM Powell ◽

MJW Peeters ◽

A Rachbech ◽

PT Straten

Keyword(s):

T Cells ◽

Cell Division ◽

T Cell ◽

Cd8 T Cells ◽

Central Memory ◽

T Cell Proliferation ◽

Flow Cytometric ◽

Donor T Cells ◽

Memory Differentiation

BackgroundOverexpression of TAM receptors, including MERTK, in some cancers are integral for chemoresistance, proliferation and metastasis.1 Our group has previously demonstrated that T cells also express MERTK and engagement of MERTK signaling is responsible for increased proliferation, functional capacity and metabolic fitness.2 It is therefore important to further study the effect of MERTK inhibition on T cell function in the context of cancer treatments where MERTK inhibitors may play a role. Here we provide evidence that MERTK inhibition impacts greatly on T cell proliferation, specifically reducing phosphorylated mTOR. We have also demonstrated that MERTK expression is increased on CD8 central memory subsets during longterm expansion providing evidence that this signaling pathway may be important for sustaining T memory responses.Materials and MethodsFlow cytometric analysis was used to investigate the effect of titration of MERTK small molecule inhibitor UNC2025 on healthy donor T cells activated with CD3/CD28 dynabeads. Cell trace dye was used to track proliferation of CD4 and CD8 T cells along with markers of memory differentiation (CCR7 and CD45RO), activation (CD137) and function (IFNy, Tnfa and IL-2). MERTK signaling was assessed using phospho flow cytometric methodology of phosphorylated mTOR, AKT, ERK1/2, p38-MAPK and STAT5. Long term cultures of donor T cells of up to 28 days were investigated for MERTK expression alongside memory differentiation.ResultsWe demonstrated that moderate concentrations of MERTK inhibitor reduced proliferation of activated T cells. Despite inhibition of cell division, cell size still increased 2 fold compared to resting cells and cell viability remained unchanged. Additionally, the proportion of central memory to effector memory populations and intracellular cytokine production was not impacted. Analysis of molecules involved in MERTK signaling revealed that phosphorylated mTOR was significantly modulated following the addition of MERTK inhibitor. Long term culture of CD8 T cells demonstrated MERTK was significantly increased following early and late re-stimulation, and expression of MERTK was strongly associated with central memory subsets.ConclusionsOur results demonstrate that inhibition of MERTK signaling on T cells reduces cell division where mTOR is significantly impacted. Despite this, other functional aspects, such as intracellular cytokine production remain unchanged. Therefore, interruption of MERTK signaling on T cells has a specific effect on cell division rather than cytotoxic function on a cell by cell basis. This has potential ramifications on the use of MERTK inhibitors to treat tumors where the ability to form substantial cytotoxic T cell populations might be reduced. In addition, increased MERTK expression on central memory subsets during long term culture suggests this signaling pathway could be critical for generating memory pools of T cells and provide new avenues for the improvement of adoptive T cell therapy protocols.ReferencesCummings CT, Deryckere D, Earp HS, Graham DK. Molecular pathways: MERTK signaling in cancer. Clin Cancer Res 2013;19(19):5275–5280.Peeters MJW, Dulkeviciute D, Draghi A, et al. MERTK Acts as a Costimulatory Receptor on Human CD8+T Cells. Cancer Immunol Res 2019;7(9):1472–1484.Disclosure InformationR.M. Powell: None. M.J.W. Peeters: None. A. Rachbech: None. P.T. Straten: None.

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Outcome and Immune Reconstitution Following T Cell Depleted Nonmyeloablative Allogeneic Transplantation Using Matched Donors.

Blood ◽

10.1182/blood.v106.11.2036.2036 ◽

2005 ◽

Vol 106 (11) ◽

pp. 2036-2036 ◽

Cited By ~ 3

Author(s):

David A. Rizzieri ◽

Liang Piu Koh ◽

Gwynn D. Long ◽

Cristina Gasparetto ◽

Jerald Z. Gong ◽

...

Keyword(s):

T Cell ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Immunosuppressive Agents ◽

Allogeneic Transplantation ◽

Stable Phase ◽

Immune Recovery ◽

Post Transplant ◽

Donor Cells

Abstract To minimize toxicity and monitor immune recovery without interference of long term use of immunosuppressive agents, we have investigated T-cell depleted, nonmyeloablative allogeneic therapy using matched family member donors. Methods: Seventy five patients who were not candidates for ablative therapy due to age or comorbid diseases received fludarabine 30mg/sq m and cyclophosphamide 500mg/sq m IV qd x 4 with alemtuzumab 20mg IV qd x 5 followed by stem cell infusion. No other post transplant immunomodulation was provided. Results: Patient diagnoses included lymphoma/myeloma (20), leukemias/MDS (30), myelofibrosis/aplasia (7) and metastatic solid tumours (18). The median age was 50 (range 18–17) with a median follow up of 18 months. The median CD34+ cell dose collected was 13.4 x 106/kg. Engraftment occurred in 100% of patients with a median of 97% donor cells responsible for patient hematopoiesis by 3 months. Forty six also had a DLI (range 106–108 CD3+ cells/kg). Overall, Grade III–IV acute GVHD occurred in only 5/75 (7%) and 18 (29%) had grade II–IV. Four patients developed chronic GVHD. The transplant regimen was well tolerated with 4% 100 day treatment related mortality. In those with hematologic malignancies, only 7% started in remission, though 45 (60%) attained a CR. The most common cause of death in this group was progressive disease (28%), followed by infections (5%), and GVHD (5%). A subgroup of 21 of these older, more infirm patients who had high risk AML in 1–2nd CR or PR or ≥2 chronic stable phase CML, partially responding lymphoma, or severe myelofibrosis have been followed for at least 1 year. At 1 year, 13/21 (62%) remain alive and in continuing remission. Phenotypic analysis of lymphocyte subsets (measured by flow) revealed recovery at 6 months. Figure Figure T cell VBeta family recovery (spectratype analysis using PCR) revealed robust recovery by 6 months as well (first figure pre and second is 6 months post transplant), despite T depletion. Figure Figure TRECs analysis reveals little, if any, recovery in these patients for at least 12–18 months. Conclusions: Nonablative allogeneic transplantation using alemtuzumab for T cell depletion results in reliable engraftment with little acute GVHD or TRM. Immune recovery assays reveal that despite T cell purging, T cell subset and VBeta families have significant recovery by 6 months and TRECS results show the recovery is primarily from peripheral expansion of transplanted donor cells, not education of new T cells. These data possibly reflect the advantage of low dose donor lymphocyte boosts without planned long term use of immunosuppressive agents. The future challenge will to be to develop strategies to further improve immune recovery in this setting.

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Killer Immunoglobulin-Like Receptor and NOD2/CARD15 Polymorphisms Independently Influence Survival after Allogeneic Hematopoietic Stem Cell Transplanation.

Blood ◽

10.1182/blood.v110.11.2167.2167 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2167-2167

Author(s):

Sebastian Giebel ◽

Aleksandra Holowecka-Goral ◽

Izabela Nowak ◽

Tomasz Czerw ◽

Jerzy Wojnar ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Hematopoietic Stem ◽

Kir Genes ◽

Increased Risk ◽

Grade Ii ◽

Card15 Gene ◽

Grade Iii

Abstract Background: Activating and inhibitory killer immunoglobulin-like receptors (KIRs) regulate function of NK cells and a subset of T cells. KIR genotype, in particular the content of activating KIR genes is highly polymorphic. NOD2/CARD15 protein is broadly expressed in APCs and lymphocytes. Single nucleotide polymorphisms (SNPs) of this gene have been reported to impair the pathogen elimination and trigger pathologic immunologic reactions like GvHD. The goal of this prospective study was to evaluate the impact of donor’s and recipient’s KIR and NOD2/CARD15 genotypes on outcome after allogeneic hematopoietic stem cell transplantation (alloHSCT). Pateints and methods: One-hundred-two consecutive patients with hematological malignancies, aged 32(18–58)y, treated with alloHSCT from HLA-matched related (n=34) or matched unrelated donor (MUD) (n=68) were included. The conditioning regimen was myeloablative, GVHD prophylaxis consisted of CsA, Mtx, and, in case of MUD-HSCT, pre-transplant ATG. Donors and recipients were tested for 11 KIR genes as well as SNP8,12,13 of the NOD2/CARD15 gene. In addition, immune reconstitution including KIR expression on T cells, was analyzed on days +28, +56, +100, +180, and +360. Results: Overall survival (OS) rate at 2y was significantly lower in alloHSCT with at least one activating KIR mismatch compared to transplants with full compatibility (62% vs. 86%, p=0.01). In particular, the presence of at least one activating KIR in the donor with its absence in the recipient (D+R−) was associated with decreased probability of OS (60% vs. 78%, p=0.01) and DFS (58% vs. 82%, p=0.005), as well as increased incidence of non-relapse mortality (NRM) (27% vs. 7%). KIR2DS1 and KIR3DS1 D+R− mismatches resulted in increased risk of grade II–IV acute GvHD, whereas KIR2DS3 and KIR2DS2 D+R− mismatches were associated with increased risk of chronic GvHD. The presence of at least one activating KIR D+R− mismatch was associated with increased CD8+/CD4+ T cell ratio up to day +100. In all cases of incompatibility regarding KIR2DS1, KIR2DS2 and KIR3DS1, T cells with expression of respective receptors could be detected up to 360 days after alloHSCT. The presence of SNP8 of the NOD2/CARD15 gene in the recipient was associated with decreased probability of OS (20% vs. 70%, p=0.005) and DFS (20% vs. 70%, p=0.01) as well as increased incidence of NRM (60% vs. 17%) and grade III–IV acute GvHD (67% vs. 8%). In a multivariate analysis including KIR and NOD2/CARD15 polymorphisms together with other potential risk factors, increasing number of D+R− activating KIR mismatches as a linear variable appeared to independently influence OS (HR: 1.3, p=0.02), DFS (HR: 1.3, p=0.008), NRM (HR: 1.4, p=0.02), grade II–IV acute GvHD (HR: 1.4, p=0.001), and chronic GvHD (HR: 1.2; p=0.02). Recipient SNP8 of NOD2/CARD15 was predictive for OS (HR: 5.5, p=0.003), DFS (HR: 4.4, p=0.008), NRM (HR: 5.9, p=0.006), grade III–IV acute GvHD (HR: 6.1, p=0.02), and chronic GvHD (HR: 3.7; p=0.03). Conclusions: Both activating KIR D+R− mismatches and recipient SNP8 of NOD2/CARD15 appear to enhance alloreactivity and independently influence survival after alloHSCT. Evaluation of these polymorphisms may contribute to better donor selection and optimization of the alloHCT procedure.

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CD28-Directed T Cell Costimulation Blockade with Abatacept to Prevent GvHD During High-Risk Unrelated HSCT: A First-in-Disease Feasibility Trial,

Blood ◽

10.1182/blood.v118.21.4078.4078 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4078-4078

Author(s):

Leslie S. Kean ◽

Amelia Langston ◽

Muna Qayad ◽

H. Jean Khoury ◽

Divya Tiwari ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Hematologic Malignancies ◽

Feasibility Trial ◽

Effector Memory ◽

Unrelated Donor ◽

Gvhd Prophylaxis ◽

The Mean

Abstract Abstract 4078 Background: Acute GvHD remains the major cause of complications and death following unrelated-donor HSCT. In a non-human primate model, we have previously shown that in vivo costimulatory blockade of donor T-cells could provide effective protection against GVHD. To begin to explore its clinical utility, we are conducting a trial (Clinical Trials.Org # NCT01012492) to determine the feasibility of combining abatacept (CTLA4-Ig) with cyclosporine and methotrexate as acute GVHD prophylaxis for patients undergoing unrelated marrow and peripheral blood stem cell transplants for hematologic malignancies. Methods: Patients older than 12 with advanced hematologic malignancies, conditioned with either TBI/Cytoxan, Busulfan/Cytoxan or Fludarabine/Melphalan are eligible. Abatacept is administered IV on days −1, +5, +14, and +28 at 10 mg/kg in addition to standard GvHD prophylaxis consisting of cyclosporine (day −2 to day 100), and methotrexate (15 mg/m2 on day +1 and 10 mg/m2 on days +3, 6 and 11). Patients are then followed for clinical outcomes and immunologic reconstitution through day +365. Results: 9 patients (planned enrollment = 11 patients) have thus far been enrolled on the study of which 5 are evaluable for engraftment, toxicity and acute GvHD. The other four patients consist of 2 who are currently receiving abatacept, 1 who was discovered to have an ongoing viral infection at the start of the first abatacept infusion so was removed from the treatment regimen, and 1 who is awaiting transplant. The median age for the 5 evaluable patients is 47 years (17–74 years). 3 patients had AML and 2 had ALL. Patients were conditioned with Bu/Cy (n=1), TBI/Cy (n=2) and Flu/Melphalan (n=2). 4 donor-recipient pairs were allele matched at 9 of 10 loci (A, B, C, DRB1 and DQB1), while 1 was fully matched. Four of the 5 patients are currently alive and in remission and 1 relapsed at day +98 (and died on day +121 with refractory AML). The four other patients are surviving without relapse with a follow-up of 155–313 days. All 5 patients received the 4 scheduled abatacept doses. No infusional side effects were noted. All patients achieved neutrophil engraftment (median day +20 (11–47). 4 of 5 patients have achieved platelet engraftment (median day +27 (14–35). Donor engraftment (100% CD33 and 99–100% CD3 at Day +30) occurred in all cases. All patients have demonstrated rapid lymphocyte engraftment, with the mean ALC reconstituting to >500 cells/μL by day +21 post-transplant. At day +100, the mean CD3+ count was 673 +/− 251 cells/μL. Both CD8+ and CD4+ T cells reconstituted by day 100, with the mean CD8+ count = 384 +/− 148 cells/μL and the mean CD4+ count = 229 +/− 119 cells/μL. T cell reconstitution was accompanied by a shift away from naïve (Tn, CCR7+/CD45RA+) toward a CCR7-/CD45RA- effector memory (Tem)-predominant phenotype. Thus, the average proportion of CD4+ Tem cells in the recipient increased from 22 +/− 6% pre-transplant to 46 +/− 7% at day +100 with a concomitant loss of CD4+ Tn cells. Likewise, the proportion of CD8+ Tem also significantly increased, from an average of 15 +/− 4% pre-transplant to 32 +/− 7% at day +100, also with a reciprocal decrease in CD8+ Tn cells. One patient developed steroid responsive grade 3 acute GVHD involving the skin and the liver, followed by steroid responsive liver chronic GvHD. This patient is currently weaning corticosteroids. Another patient developed steroid responsive late-onset (day +217) acute GVHD (liver and GI) during cyclosporine weaning, which was also steroid responsive, and is also currently weaning corticosteroids. No other systemic acute or chronic GvHD has occurred. No unexpected complications or life-threatening infections were observed. 3 patients have experienced 5 episodes of CMV reactivation, all responsive to antiviral therapy. One patient developed polyclonal EBV-related PTLD (plasmacytic hyperplasia) in the absence of EBV viremia, which regressed without intervention. No other EBV-related disease has occurred. Conclusions: These preliminary data suggest that abatacept can be safely added to cyclosporine and methotrexate for GVHD prophylaxis in recipients of hematopoietic grafts from unrelated donors, with encouraging rates of acute GVHD. As such, they support the conduct of a larger, randomized phase 2 study. Disclosures: Off Label Use: Abatacept: It is an immunosuppressive agent that targets the CD28/B7 T cell costimulation pathway. It is approved for use in Rheumatoid arthritis.

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Delta-like Ligands Expressed By Stromal Cells in Secondary Lymphoid Organs Deliver an Early Pulse of Notch Signaling and Drive T Cell Pathogenicity in Acute Graft-Versus-Host Disease

Blood ◽

10.1182/blood.v124.21.841.841 ◽

2014 ◽

Vol 124 (21) ◽

pp. 841-841

Author(s):

Jooho Chung ◽

Christen L. Ebens ◽

Vedran Radojcic ◽

Ute Koch ◽

Ann Friedman ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Notch Signaling ◽

Stromal Cells ◽

Acute Gvhd ◽

Hematopoietic System ◽

Alloreactive T Cells ◽

Equity Ownership

Abstract Notch signaling is a critical regulator of T cell effector functions during acute graft-versus-host disease (GVHD). Pan-Notch inhibition in donor-derived T cells or systemic antibody-mediated blockade of Delta-like1 (Dll1) and Delta-like4 (Dll4) Notch ligands results in near-complete protection from acute GVHD in mouse models of allogeneic bone marrow transplantation. Notch-deprived alloreactive T cells proliferate and accumulate in vivo, but produce dramatically reduced levels of the proinflammatory cytokines IFNγ, TNFα and interleukin-2 (IL-2) (Zhang et al., Blood 2011; Sandy et al., J Immunol 2013; Tran et al., J Clin Invest 2013). In this study, we sought to: 1) determine the kinetic requirements for Notch signaling in the pathogenesis of acute GVHD; 2) identify the essential cellular compartment that delivers Dll1 and/or Dll4 ligands to incoming alloreactive T cells. In the B6 anti-BALB/c major histocompatibility complex-mismatched model, a single dose of Dll1 and Dll4 blocking antibodies at the time of transplantation abolished alloreactive T cell production of IFNγ, TNFα, and IL-2, increased regulatory T cell numbers (as assessed at day 10), and conferred long-term protection from GVHD. Conversely, delaying antibody administration by only two days after transplantation resulted in persistent T cell cytokine production, no changes in regulatory T cell numbers, and loss of long-term protection from GVHD. These findings identify a critical early window of Notch activity that promotes the pathogenesis of acute GVHD. To identify the dominant cellular source of Dll1 and Dll4, we assessed the impact of Cre-mediated Dll1 and Dll4 inactivation within host hematopoietic, donor hematopoietic, or host non-hematopoietic tissues. Bone marrow chimeras that lacked Dll1 and Dll4 solely within the host hematopoietic system were generated from poly(I:C)-induced Mx1-Cre;Dll1fl/fl;Dll4fl/fl donor mice. Both donor chimerism and Cre-mediated excision efficiency were >97%. Unlike systemic Dll1/4 blockade, Dll1 and Dll4 inactivation within the host hematopoietic system failed to decrease GVHD mortality or severity. Likewise, Mx1-Cre-mediated deletion of Dll1 and Dll4 within the donor hematopoietic system had minimal effects on T cell proinflammatory cytokines. In contrast, Ccl19-Cre-mediated Dll1 and Dll4 inactivation within host stromal cells profoundly impaired donor T cell production of IFNγ, TNFα, and IL-2, and resulted in long-term protection from GVHD. Lineage tracing in Ccl19-Cre x ROSA26-YFP mice revealed Cre activity within a small subset of CD45-negative lymph node and spleen stromal cells, but not in professional hematopoietic antigen-presenting cells. These data suggest that a specialized subset of non-hematopoietic stromal cells delivers an early pulse of Notch signaling to alloreactive T cells during acute GVHD. To our knowledge, these results provide the first in vivo evidence for non-motile secondary lymphoid-resident stromal cells as critical drivers of T cell-mediated immune pathology, with a central role for Notch signaling in this process. Transient interference with Notch ligand function or with their expression by the stromal cell niche in the peri-transplant period could serve as a novel therapeutic strategy for GVHD. Disclosures Yan: Genentech: Employment, Equity Ownership. Siebel:Genentech: Employment, Equity Ownership.

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