scholarly journals Dynamical Systems Modeling of Early-Term Immune Reconstitution with Different Anti-Thymocyte Globulin (ATG) Administration Schedules in Allogeneic Stem Cell Transplantation.

2021 ◽  
Author(s):  
Viktoriya Zelikson ◽  
Amir Ahmed Toor ◽  
Gary Simmons ◽  
Natasha Raman ◽  
Elizabeth Krieger ◽  
...  
Keyword(s):  
T Cell ◽  
Clinical Outcomes ◽  
Cell Transplantation ◽  
Immune Reconstitution ◽  
Cellular Therapy ◽  
Immune Cell ◽  
Chronic Gvhd ◽  
T Cell Response ◽  
Cell Recovery ◽  
Early Term

Alloreactivity forms the basis of allogeneic hematopoietic cell transplantation (HCT), with donor derived T cell response to recipient antigens mediating clinical responses either in part or entirely. These encompass the different manifestations of graft vs. host disease (GVHD), infection risk as well as disease response. Whilst the latter is contingent upon disease biology and thus may be less predictable, the former two are more likely to be directly proportional to the magnitude of donor derived T cell recovery. Herein we explore the quantitative aspects of immune cell recovery following allogeneic HCT and clinical outcomes in two cohorts of HLA matched allograft recipients who received rabbit anti-thymocyte globulin (ATG) on different schedules (days -9 to -7 vs. -3 to -1). Monocyte as well as donor derived T cell (ddCD3) recovery was superior in those given ATG early in their course (days -9/-7). This difference was related to a more rapid rate of ddCD3 recovery, largely driven by CD3+/8+ cells in the first month following transplantation. Early monocyte recovery was associated with later T cell recovery, improved survival, and less chronic GVHD. In contrast rapid and early ddCD3 expansion out of proportion to monocyte recovery was associated with a high likelihood of acute GVHD and poor survival. This analytic methodology demonstrates that modeling 'early-term immune reconstitution' following HCT yields insights that may be useful in management of post-transplant immunosuppression and adaptive cellular therapy to optimize clinical outcomes.

Immune Reconstitution In Anti-Thymocyte Globulin Conditioned Unrelated Donor Stem Cell Transplantation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2071-2071 ◽  
Author(s):  
David Jared Kobulnicky ◽  
Roy T Sabo ◽  
Allison F Scalora ◽  
David Portier ◽  
Devon Fletcher ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Immune Reconstitution ◽  
Unrelated Donor ◽  
Cell Recovery ◽  
Ebv Reactivation ◽  
Stem Cell Source ◽  
Cell Source

Abstract Anti-thymocyte globulin (ATG) is widely used for in vivo T cell depletion and immunomodulation in unrelated donor (URD) stem cell transplantation (SCT) to reduce the risk of graft vs. host disease (GVHD). However, despite the reduction in GVHD risk, outcomes are generally not superior to matched related donor (MRD) SCT conditioned without ATG. This is primarily because of defective immune reconstitution and high rates of opportunistic infections in ATG recipients. We have previously reported equivalent outcomes in URD SCT recipients conditioned with ATG when compared to MRD recipients. We now report immune reconstitution in an expanded cohort of these patients. Patients with AML, ALL, MDS, MPD (n=142) transplanted between 2004 and 2011 were included in this retrospective review. Seventy eight received either bone marrow or peripheral blood stem cell (PBSC) grafts from URD and received either 10 or 7.5 mg/kg rabbit ATG (Thymoglobulin, Sanofi-Aventis) during conditioning, those with MRD did not. Conditioning was myeloablative in all patients. Lymphoid recovery was equivalent in the two cohorts during the first year following SCT except in the first month (Figure), when URD recipients had lower absolute lymphocyte count (μ-URD=0.6x103/ μ L, μ-MRD=1.1; repeated measures mixed model p=0.022). Age, CD3/34 cell dose infused, stem cell source and conditioning intensity were not associated with ALC recovery post transplant. In a subset of patients lymphocyte subset enumeration was performed following withdrawal of immunosuppression, at an average 237 days post-SCT. ATG recipients had significantly lower mean CD4+ counts (μ-URD=267 (n=30), μ-MRD =434/ μ L (n=27); ANCOVA p = 0.003), however no significant differences were observed in CD3+, CD8+, CD19+ or CD56+ cell recovery. ATG recipients were significantly more likely to have complete donor T cell chimerism at 1 (OR = 12.5, CI= 2.4, 66.0, p = 0.001) and 2 months post-SCT (OR = 6.5 , CI=1.5, 27.4, p = 0.013), however by 9 months following SCT this trend had reversed with a greater likelihood of mixed T cell chimerism (OR > 100; p = 0.017), suggesting re-emergence of recipient derived T cell clones. Consequently, donor lymphocyte infusions were given significantly more often to ATG recipients (12/78) than to non-recipients (2/64) (OR = 5.64, CI = 1.21, 26.20, p=0.027). High grade CMV viremia (1000 copies/ μL) was significantly more likely in CMV sero-positive ATG recipients (n=18/55) than in non-recipients (n=7/48) (OR = 2.8, CI 1.1, 7.6, p = 0.032). Reduced intensity conditioning and PBSC were associated with higher CMV reactivation in ATG recipients and there was a lower likelihood of survival in these individuals than in those who did not receive ATG (HR: 0.53, CI: 0.31, 0.92; p = 0.024). EBV reactivation was observed more often in susceptible ATG recipients (n=22/58) than in non-recipients (n=5/43), (OR=4.6, CI=1.6, 13.6, p= 0.003). The median peak EBV viral load in ATG recipients (u=1545 copies/ μL, IQR: 288, 2,302) was significantly higher than in non-recipients (u=120 IQR: 57, 169, p = 0.005). PBSC stem cell source (p = 0.049) and HLA mismatch (p =< 0.001) were associated with EBV reactivation in ATG recipients but not in non-recipients. ATG recipients were also more likely to experience a fungal infection (OR=2.8, CI=1.1, 6.7, p=0.023). 1-month ALC was predictive of disease free survival whereby it had a significant negative effect on relapse (HR = 0.33; 95% CI: 0.16, 0.66; p = 0.002). As 1-month ALC increased by one-tenth, the odds of relapse decreased by over 3% and survival increased by 3%. In conclusion, high doses of ATG used during conditioning are associated with an early retardation of lymphoid recovery post-SCT, and with late mixed T cell chimerism accompanied by a delay in CD4+ T cell recovery. This is associated with a higher rate of viral reactivation in PBSC recipients and of fungal infections in general. Lower doses of ATG should be used in SCT and in ATG conditioned SCT, early intervention with DLI, particularly CD8+ cell depleted DLI as reported by others, may help restore T cell repertoire and improve SCT outcomes and survival. Disclosures: Toor: Sanofi Avnetis: Research Funding.

Oligoclonal T Cells Associated with Gvhd Following Allogeneic Stem Cell Transplantation Conditioned with Thymoglobulin and Reduced Intensity Total Body Irradiation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4662-4662
Author(s):  
Masoud Manjili ◽  
Catherine H Roberts ◽  
Maciej Kmieciak ◽  
Madhu S Gowda ◽  
Andrea Ferreira-Gonzalez ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Count ◽  
Cell Transplantation ◽  
Acute Gvhd ◽  
Chronic Gvhd ◽  
Cell Recovery ◽  
Reduced Intensity

Abstract Abstract 4662 Patients undergoing unrelated donor stem cell transplantation following reduced intensity regimens are prone to acute graft vs host disease (GVHD). In vivo T cell depletion with rabbit anti-thymocyte globulin (r-ATG, Thymoglobulin, Genzyme inc. Cambridge MA) is consistently associated with reduced risk of acute GVHD however poor T cell reconstitution seen with current schedules results in a high incidence of opportunistic infections and relapse. We report data on immune reconstitution in patients participating in an ongoing clinical trial testing a novel conditioning regimen for allogeneic GCSF-mobilized blood stem cell transplantation. Patients were randomized to receive conditioning with either 7.5 or 5.1 mg/kg of r-ATG in divided doses between days -9 and -7, followed by 450 cGy total body irrradiation (TBI) in 3 fractions on day -1 and 0. GVHD prophylaxis was with tacrolimus (day -3 to 120) and mycophenolate mofetil (day 0-30). So far 10 heavily pre-treated (median number of prior therapies 4, prior autologous SCT n=5) patients have been transplanted; 6 from unrelated donors (1 bone marrow), 3 from matched related donors and 1 from an HLA-A mismatched sibling. Diagnosis includes MM (4), NHL (3), and CLL/PLL (3). Median patient age is 57 years. No patients have developed acute GVHD in the first 90 days. All patients achieved prompt engraftment of neutrophils and have demonstrated sustained complete myeloid donor chimerism (median <1% recipient DNA) at 3-6 months post transplant. NK cell recovery is prompt (mean±SD absolute CD56+ cell count 177±85/μL at day 30) and sustained (184±116 at day 90). T cell subset recovery is modest (absolute CD3+ cell count 861±934/μL at day 90) with predominantly cytotoxic T cells (CD3+/4+ cell count 143±116 and CD3+/8+ cell count 708±837). T cell chimerism at day 90 is mixed with either donor ('10% recipient DNA, n=5) or recipient dominance (>10% recipient DNA, n=3). Patients demonstrating dominant donor T cell chimerism at day 90 went on to develop either delayed onset acute GVHD (n=2/8 evaluable) or chronic GVHD (n=2/8) after withdrawal of immunosuppression. Patients demonstrating mixed T cell chimerism with recipient dominance did not develop chronic GVHD; one of these patients has relapsed, following an HLA-A mismatched SCT from his brother, and though he had predominantly recipient derived T cells, his granulocytes were completely donor derived indicating graft tolerance. T cell receptor beta locus was examined by RT-PCR for oligoclonality in all the donor-recipient pairs at baseline, day 90 and at onset of GVHD. Patients with GVHD demonstrated high level of expression of TCR V beta 23 and 24 (n=1/4), 11 (n= 1/4), 18 (n= 1/4), or 11 and 18 (n= 1/4) exclusively, in addition to TCR V beta 14, 16, 17, 22. The latter loci were also expressed in patients who had no GVHD with mixed T cell chimerism; this group of patients also expressed TCR V beta 4 (n=2/2), 13 and 19 (n=1/2) exclusively. All but one of the patients expressed the majority of TCR V beta loci at day 90 (with the exceptions noted above) indicating early polyclonal T cell recovery following transplantation. Asymptomatic CMV and EBV reactivation requiring therapy developed in one patient each. No patients have developed invasive fungal infections. In conclusion conditioning with Thymoglobulin and reduced intensity TBI results in stable myeloid engraftment in patients receiving unrelated and alternative donor transplants. In this small group of patients, GVHD appears to be associated with emergence of oligoclonal T cell populations which in the future may be selectively depleted ex vivo to allow engraftment without risk of chronic GVHD. Disclosures: McCarty: Celgene: Honoraria; Genzyme: Honoraria. Toor:Genzyme: Research Funding.

Haploidentical Stem Cell Transplantation: High Doses of Alloreactive-T Cell Depleted Donor Lymphocytes Administered Post-Transplant Decrease Infections and Improve Survival without Causing Severe Gvhd.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 512-512 ◽  
Author(s):  
Denis-Claude Roy ◽  
Silvy Lachance ◽  
Thomas Kiss ◽  
Sandra Cohen ◽  
Lambert Busque ◽  
...  
Keyword(s):  
Clinical Trial ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Immune Reconstitution ◽  
Chronic Gvhd ◽  
T Cell Depletion ◽  
Post Transplant

Abstract Abstract 512 Delayed immune reconstitution following intensive T cell depletion of the stem cell graft is the main complication limiting broad utilization of haplo-mismatched donors for stem cell transplantion (SCT). Indeed, it results in frequent and rapidly lethal infectious events. The ability to accelerate immune reconstitution following haplo-SCT would provide a unique opportunity to transplant the large number of patients who cannot find an HLA-matched donor. We present results of our Phase I clinical trial of haploidentical allogeneic SCT followed by an “add-back of donor T cells to accelerate immune reconstitution” (ATIR). This donor lymphocyte infusion (DLI) underwent photodynamic depletion (PD) of host-reactive T cells using dibromorhodamine as photosensitizer (Kiadis Pharma). Nineteen patients (11 M, 8 F) with very high-risk hematologic malignancies (mostly refractory or relapsed acute myeloid leukemia (10) and myelodysplastic syndromes (4), and refractory ALL (1), CLL (2), CML (1) and NHL (1)) entered the trial. Median age at SCT was 54 years (range: 19-62). HLA compatibility was 3/6 in 6 pts, 4/6 in 12 pts and 5/6 (DR mismatch) in 1 pt. Increasing doses of PD-treated donor cells (ATIR: 1×104 to 5.0 ×106 CD3+ cells/kg) were administered on day 34±6 after transplant. In the ATIR, greater than 95% of CD4+CD25+ and CD8+CD25+ T cells as well as anti-host cytotoxic T lymphocyte precursors (CTLp) were depleted from DLIs. All stem cell grafts underwent in vitro immunomagnetic T cell depletion using CD34+ positive cell selection (Miltenyi). The myeloablative regimen consisted of TBI (1200 cGy), thiotepa (5 mg/kg) and fludarabine (200 mg/m2). No GVHD prophylaxis was administered. All patients showed complete donor chimerism and durable hematologic engraftment. Five patients developed grade II GVHD affecting skin (n = 5 pts), liver (2 pts) and gastrointestinal tract (1 pt) at a median of 101 days post-SCT. No patient developed grade III-IV acute GVHD. Chronic GVHD developed in 9 pts, mostly in those receiving higher T cell doses. Treatment of acute and chronic GVHD involved steroids, tacrolimus and mycophenolate mofetil in 3 patients, steroids and tacrolimus in 3 pts, and steroids only in 3 pts. GVHD responded rapidly to treatment since the median duration of total immunosuppressive therapy in each patient was 187 days (range: 61-319 d). All 7 patients in cohorts 1-3, who received 1.3×105 or less CD3+ cells/kg, developed infectious complications (100% of pts), with 5 lethal episodes in these 7 pts. In sharp contrast, only 6 (50%) of the following 12 patients (cohorts 4-7) receiving ATIR with the highest CD3+ cell doses (3.2×105 to 5.0×106 CD3+ cells/kg) developed infections (p <0.05), none resulting in a fatal event (p<0.001). Interestingly, CD3 lymphocytes recovered earlier in the last 2 cohorts (6 and 7) receiving 2-5×106 CD3+ cells/kg than in the first 5 cohorts (7.9×105 or less CD3+ cells/kg) (p<0.01). Eight patients died: 4 of relapsed leukemia (3 AML; 1 ALL) and 4 of infections. Overall treatment related mortality (TRM) is 27% at 2 years post-SCT, with a TRM of 0% in patients receiving the highest CD3+ cell doses (cohorts 4-7). The overall survival is 60% at 2 years (median f-up: 12.1 mo; 95% confidence interval at 2 years: 37-83%). The 12 patients in cohorts 4-7 receiving the higher CD3+ cell doses had an improved survival (82% at 2 yrs) over the 7 patients in cohorts 1-3 administered a lower CD3+ cell dose (14% at 2 yrs) (p<0.05). Our results indicate that the post-transplant infusion of an ATIR-PD treated DLI is feasible, results in accelerated T cell reconstitution, and decreases the incidence and severity of infections without inducing severe GVHD. These results suggest a clinical benefit for patients receiving the highest ATIR doses and form the basis of an international pivotal clinical trial to decrease TRM in patients undergoing haploidentical stem cell transplantation. Disclosures: Roy: Kiadis Pharma: Research Funding. Egeler:Kiadis Pharma: Employment.

scholarly journals Immune Reconstitution After Allogeneic Haematopoietic Cell Transplantation: From Observational Studies to Targeted Interventions

2022 ◽  
Vol 9 ◽  
Author(s):  
Asaf Yanir ◽  
Ansgar Schulz ◽  
Anita Lawitschka ◽  
Stefan Nierkens ◽  
Matthias Eyrich
Keyword(s):  
T Cells ◽  
Cell Transplantation ◽  
Immune Reconstitution ◽  
Immune Cell ◽  
Infectious Complications ◽  
Cell Recovery ◽  
Targeted Interventions ◽  
Post Transplant ◽  
Haematopoietic Cell ◽  
Allogeneic Haematopoietic Cell Transplantation

Immune reconstitution (IR) after allogeneic haematopoietic cell transplantation (HCT) represents a central determinant of the clinical post-transplant course, since the majority of transplant-related outcome parameters such as graft-vs.-host disease (GvHD), infectious complications, and relapse are related to the velocity, quantity and quality of immune cell recovery. Younger age at transplant has been identified as the most important positive prognostic factor for favourable IR post-transplant and, indeed, accelerated immune cell recovery in children is most likely the pivotal contributing factor to lower incidences of GvHD and infectious complications in paediatric allogeneic HCT. Although our knowledge about the mechanisms of IR has significantly increased over the recent years, strategies to influence IR are just evolving. In this review, we will discuss different patterns of IR during various time points post-transplant and their impact on outcome. Besides IR patterns and cellular phenotypes, recovery of antigen-specific immune cells, for example virus-specific T cells, has recently gained increasing interest, as certain threshold levels of antigen-specific T cells seem to confer protection against severe viral disease courses. In contrast, the association between IR and a possible graft-vs. leukaemia effect is less well-understood. Finally, we will present current concepts of how to improve IR and how this could change transplant procedures in the near future.

scholarly journals Delayed immune reconstitution after allogeneic transplantation increases the risks of mortality and chronic GVHD

2018 ◽  
Vol 2 (8) ◽  
pp. 909-922 ◽  
Author(s):  
Nelli Bejanyan ◽  
Claudio G. Brunstein ◽  
Qing Cao ◽  
Aleksandr Lazaryan ◽  
Xianghua Luo ◽  
...  
Keyword(s):  
T Cell ◽  
B Cell ◽  
Immune Reconstitution ◽  
Chronic Gvhd ◽  
Allogeneic Transplantation ◽  
Risk Of Infection ◽  
Cell Recovery ◽  
T Cell Reconstitution ◽  
Key Points ◽  
Naive T Cell

Key Points UCB recipients have slower T-cell reconstitution but more robust NK and B-cell recovery after allo-HCT than MSD recipients. Delayed CD4+ total and naive T-cell reconstitution after allo-HCT increases the risk of infection, mortality, and chronic GVHD.

Phase 1 Clinical Study of Adoptive Immunotherapy with Delayed Infusion of Alloanergized Donor T Cells to Improve Immune Reconstution after Haploidentical Stem Cell Transplantation.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1156-1156
Author(s):  
Jeff Davies ◽  
Marcos De Lima ◽  
Laurence Cooper ◽  
Thomas Spitzer ◽  
Neena Kapoor ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Immune Reconstitution ◽  
Chronic Gvhd ◽  
Optimal Dose ◽  
Effector Memory ◽  
Donor T Cells

Abstract Haploidentical related donors extend availability of hematopoietic stem-cell transplantation (HSCT) to patients (pts) lacking HLA-matched family donors, but profound T-cell depletion (TCD) is needed to prevent severe GvHD, thus delaying immune reconstitution and increasing infection. Adoptive transfer of alloanergized donor T cells is an attractive approach to reconstituting T cell number and function with concomitant GVHD abrogation. We established proof-of-principle in haploidentical bone marrow (BM) transplant trials using ex vivo induction of recipient alloantigen-specific anergy in T cells within donor BM by allostimulation with blockade of CD28-mediated costimulation. This strategy permitted infusion of large doses of haploidentical T cells with donor BM, resulting in rapid immune reconstitution without excess severe GvHD or chronic GVHD. However the optimal dose of alloanergized donor T cells and their impact on functional antigen-specific immune reconstitution were not determined in our prior studies. We now report the results to date of a new study evaluating delayed infusion of escalating doses of donor PBMC anergized to recipient alloantigens after haploidentical HSCT. Alloanergized PBMCs were generated by co-culture of irradiated stimulator PBMC from a second haploidentical related donor (or the pt) using clinical grade humanized monoclonal anti-B7.1 and –B7.2 antibodies. 7 adults (median age 41, range 22–50) and 4 children (median age 7.5, range 2–14) with high risk leukemia/MDS (8 AML (3 CR1 4 CR2, 1 persistent disease), 2 high-IPSS MDS and 1 ALL (CR2) have been treated. Pts received fractionated TBI (1200cGy, n=5) or melphalan (140mg/m2, n=6), fludarabine, thiotepa and ATG followed by CliniMacs CD34-selected peripheral blood stem cells (PBSC) from haploidentical family donors without subsequent pharmacologic GVHD prophylaxis. Median infused cell doses (x 106/kg) were 9.4 (CD34+) and 0.02 (CD3+). All pts engrafted and attained full donor chimerism, with rapid neutrophil and platelet recovery (median D+11 and D+12, respectively). Using novel Bayesian phase I/II adaptive design, 10 pts have received donor PBMC after alloanergization (which resulted in a median 6-fold reduction in alloresponses): Dose (Ds)1, 103 CD3+ cells/kg (n=4), Ds2 104/kg (n=3) and Ds3 105/kg (n=3), infused on D+35 (n=8) or D+42 (n=2) without developing severe acute GvHD (Table). None of 5 evaluable pts developed chronic GvHD. At median follow-up of 8 months (range 1–23), 8/11 pts are alive. 6/11 pts are disease-free. 3 pts have died, from bacterial sepsis (Day +32), pulmonary veno-occlusive disease (D+59), and idiopathic pulmonary syndrome (D+78). Two AML pts have relapsed. Infusion of alloanergized donor PBMC appears to influence reconstitution of both CD4 T cell numbers and functional pathogen-specific T cells (Table). Normal SEB responses and functional CMV- and VZV-specific CD4 and CD8 T cells became detectable at 6–9 months in pts at Ds1, at 3 months in pts at Ds2 and at 2 months in the assessable pt at Ds3. Recovering T cells had a predominantly effector memory phenotype consistent with peripheral expansion of infused alloanergized donor T cells. These data suggest that delayed infusion of modest doses of alloanergized donor PBMC after haploidentical HSCT is not associated with significant GVHD, and may be associated with a dose-dependent improvement of quantitative and qualitative immune reconstitution. Ongoing recruitment of patients to higher alloanergized PBMC dose levels (up to 107/kg if tolerated) will determine the optimal dose that benefits immune reconstitution without causing severe GVHD. Infusion of Alloanergized PBMC GvHD New CMV reactivation Dose Level Pts T cell dose/kg Acute (Grade) Chronic Before PBMC infusion After PBMC infusion EBV/HSV infection after PBMC infusion Median time to CD4 ct &gt;100** (months) Months to detectable CMV/VZV IFN-gamma + T cells * only one evaluable pt at this time, TBD; to be determined: ** cells/microliter 1 4 103 0/4 0/2 2/4 0/4 2/4 9 6-9 2 3 104 1/3 (2) 0/3 2/3 0/3 0/3 4 3 3 3 105 1/3 (1) TBD 1/3 0/3 0/3 2* 2*

Graves’ disease as immune reconstitution disease in HIV-positive patients is associated with naive and primary thymic emigrant CD4+ T-cell recovery

AIDS ◽  
2014 ◽  
Vol 28 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Virginia Sheikh ◽  
Rebecca Dersimonian ◽  
Aaron G. Richterman ◽  
Brian O. Porter ◽  
Ven Natarajan ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Reconstitution ◽  
Cd4 T Cell ◽  
Hiv Positive ◽  
Graves Disease ◽  
Cell Recovery

scholarly journals Repeated vaccination against SARS-CoV-2 elicits robust polyfunctional T cell response in allogeneic stem cell transplantation recipients

Cancer Cell ◽  
2021 ◽  
Vol 39 (12) ◽  
pp. 1654
Author(s):  
Patrick Harrington ◽  
Katie J. Doores ◽  
Chandan Saha ◽  
Jamie Saunders ◽  
Fiona Child ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Allogeneic Stem Cell Transplantation ◽  
Cell Response ◽  
T Cell Response

New Developments in Allotransplant Immunology

Hematology ◽  
2003 ◽  
Vol 2003 (1) ◽  
pp. 350-371 ◽  
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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