Antithymocyte Globulin Group Research Articles

Immune Tolerance Developed in Platelet-Targeted FVIII Gene Therapy in Hemophilia Mice Is CD4+ T Cell-Mediated

Immune response to factor VIII (FVIII) is not only a severe complication in protein replacement therapy, but also a major concern in gene therapy of hemophilia A. Our previous studies have demonstrated that platelet-targeted FVIII (2bF8) gene therapy together with in vivo drug-selection of transduced cells can not only rescue the bleeding diathesis but also induce anti-FVIII specific immune tolerance in FVIIInull mice. In the current study, we investigated 1) whether our non-selectable lentiviral vector (LV) for the induction of platelet-FVIII expression is sufficient to induce immune tolerance and 2) which cell compartment is tolerized after platelet gene therapy. Platelet-specific FVIII expression was introduced by 2bF8LV-transduction of hematopoietic stem cells followed by syngeneic transplantation into FVIIInull mice preconditioned with 660 cGy total body irradiation (TBI) or Busulfan (Bu) plus ATG (anti-thymocyte globulin). After bone marrow transplantation and reconstitution, animals were analyzed by PCR, qPCR, FVIII:C assay, and tail clipping test to confirm the success of 2bF8 gene therapy. Sixteen weeks after transplantation, animals were challenged with recombinant human FVIII (rhF8) via retro-orbital venous administration at a dose of 50 U/kg weekly for 4 weeks. The titers of anti-FVIII inhibitory antibodies (inhibitors) were determined by Bethesda assay. The CFSE-labeled CD4 T cell proliferation assay and ELISPOT-based memory B cell maturation assay were used to determine which cell compartment is tolerized to FVIII after 2bF8 gene therapy. The level of platelet-FVIII expression was 1.44 ± 0.39 mU/108 platelets (n = 6) in the 660 cGy group, which is not significantly different from the level obtained from the Bu+ATG group [3.04 ± 1.19 mU/108 platelets (n = 6)]. Even after rhF8 challenge, no antibodies were detected in 2bF8LV-transduced recipients in either group. In contrast, all animals in the control group that did not undergo gene therapy developed various levels of inhibitors (204±97 BU/ml, n=7). The frequency of regulatory T cells in both 660 cGy TBI (11.01±0.52%) and Bu+ATG (11.02±0.68%) groups were significantly higher than the control group (8.05±0.57%). T cell proliferation assay demonstrated that CD4+ T cells from 2bF8 LV-transduced recipients that had been challenged with rhF8 did not proliferate when restimulated with rhF8 in vitro. The daughter CD4+ T cells in the group with 10 U/ml of rhF8 were 5.84 ± 2.49% (n = 6), which was not significantly different from the control group without no rhF8 stimulation (0 U/ml) (5.33 ± 1.72%). CD4+ T cells from primed FVIIInull mice did proliferate after rhF8 restimulation. The proliferated daughter cell was 13.12 ± 6.76% (n = 7) in the group with rhF8 (10 U/ml) re-stimulation, which is significantly higher than the group without rhF8 co-culture (4.99 ± 1.16%). Since FVIII-specific memory B cell maturation is CD4+ T cell dependent, we isolated CD4+ T and memory B cells from 2bF8LV-transduced or FVIIInull mice after rhF8 immunization and co-cultured with rhF8 followed by ELISPOT assay to examine the antibody secreting cells. No spots were detected when memory B cells from rhF8-primed FVIIInull mice were co-cultured with CD4+ T cells from 2bF8LV-transduced recipients. In contrast, when memory B cells from either rhF8 immunized 2bF8LV-transduced or untreated FVIIInull mice were cultured with CD4+ T cells from rhF8-primed FVIIInull mice, there were 142 and 205 anti-FVIII antibody secreting cells, respectively, detected per 106 cells seeded. These results indicate that CD4+ T cells from 2bF8LV-transduced mice are tolerized to rhF8 stimulation. In conclusion, 2bF8 lentiviral gene transfer without in vivo selection of genetically manipulated cells can introduce FVIII-specific immune tolerance in hemophilia A mice and this immune tolerance is CD4+ T cell-mediated. DisclosuresBaumgartner:Novo Nordisk: Research Funding. Shi:BloodCenter of Wisconsin: Patents & Royalties: METHOD OF INDUCING IMMUNE TOLERANCE THROUGH TARGETTED GENE EXPRESSION..

Cytomegalovirus and Effect on Early Chimerism in Patients with Myeloid Disorders Undergoing Stem Cell Transplantation Using Reduced Toxicity Ablative Conditioning Regimen

Cytomegalovirus (CMV) remains a significant cause of morbidity after allogeneic hematopoietic stem cell transplantation (SCT). The influence of CMV on the chimerism in reduced toxicity ablative conditioning SCT in myeloid disorders is ill defined. A recent report published in Blood by Sellar et al showed that in patients who received alemtuzumab-based regimen, the group of patients who were recipient positive (R+)/ Donor negative (D-) had CMV-specific T cells that are exclusively of recipient origin and significantly influenced the chimerism status toward recipients. To explore the impact of seropositivity and seronegativity of CMV in recipients and donors on early chimerism, we undertook a retrospective analysis of patients with myeloid disorders who received four days of fludarabine and busulfan with or without anti-thymocyte globulin (ATG) at our center in the last 10 years.Methods: Chimerism assay was performed using a quantitative fluorescence-based short tandem repeat-polymerase chain reaction (STR-PCR) with capillary electrophoresis for PCR product resolution.Results: 42 patients were identified and included in the study. All patients received fludarabine (40 mg/m2/day x 4 doses), busulfan (3.2mg/kg/dose IV x 4 doses). Of these 42 patients, 25 had anti-thymocyte globulin. There were 28 male and 14 female patients with a median age of 62 years (range 48-74yrs). Median time to follow up was 8 months (0.8-54 months). Disease risk was considered advanced in 21 patients, intermediate in 4 and early in 17. Median blast number at time of SCT was 5%. Stem cell source included peripheral blood in all patients. There were no primary graft failures. Total recipient cell chimerism showed increase or persistence of recipient chimerism in 5/11 (45%) of R+D- vs 2/6 (33.3%) of R-D- in the group of patients who received ATG, p=1.0, with a mean of recipient chimerism at day 100 of 20.4% in the R+D- group compared to a mean of 17% in the R-D- group. In the group who did not get ATG, recipient chimerism persistence or increase was not that different between the R+D- patients 3/4 (75%) compared to 4/4 (100%) in patients who were seronegative for CMV (R-), p=1.0. The mean of recipient chimerism at day 100 in the R+D- no ATG group was 23.25% with a median of 12% while the mean and median at day 100 in the R- no ATG group were 35.25% and 19.5% respectively (p=0.573).When looking at the persistence or increase in recipient chimerism in the group of patients who were R+D-, in those who got ATG it was 45% increase vs 75% increase in those who did not get ATG (p=0.569) with a median of 12% vs 0% respectively (p=0.49). Also increase or persistence of recipient chimerism was 33.3 % in patients who were R- and got ATG vs 100% in R- no ATG patients (p=0.076)with median at day 100 of 0 vs 19.5% (p=0.098).Conclusion: In this small cohort from a single center, we found that in patients with myeloid disorders who received reduced toxicity ablative conditioning regimen, the group of patients who received ATG, there was no statistically significant increase in recipient chimersim in the R+D- group compared to R-D- group. This is different from what Sellar et al found in a small group of patients who received alemtuzumab. These results may indicate a difference between ATG and alemtuzumab in the effect of CMV seropositivity and negativity on the recipient chimerism, which need to be studied further in a larger retrospective or prospective study. This is especially important in myeloid disorders since persistent or increase in recipient chimerism may identify high-risk patient cohorts who may benefit from additional therapeutic interventions. DisclosuresNo relevant conflicts of interest to declare.

Impact of ATG-containing reduced-intensity conditioning after single- or double-unit allogeneic cord blood transplantation

AbstractWe analyzed 661 adult patients who underwent single-unit (n = 226) or double-unit (n = 435) unrelated cord blood transplantation (UCBT) following a reduced-intensity conditioning (RIC) consisting of low-dose total body irradiation (TBI), cyclophosphamide, and fludarabine (Cy/Flu/TBI200). Eighty-two patients received rabbit antithymocyte globulin (ATG) as part of the conditioning regimen (ATG group), whereas 579 did not (non-ATG group). Median age at UCBT was 54 years, and diagnoses were acute leukemias (51%), myelodysplastic syndrome/myeloproliferative neoplasm (19%), and lymphoproliferative diseases (30%). Forty-four percent of patients were transplanted with advanced disease. All patients received ≥4 antigens HLA-matched UCBT. Median number of collected total nucleated cells was 4.4 × 107/kg. In the ATG group, on 64 evaluable patients, ATG was discontinued 1 (n = 27), 2 (n = 20), or > 2 days before the graft infusion (n = 17). In multivariate analyses, the use of ATG was associated with decreased incidence of acute graft-versus-host disease (hazard ratio [HR], 0.31; 95% confidence interval [CI], 0.17-0.55; P < .0001), higher incidence of nonrelapse mortality (HR, 1.68; 95% CI, 1.16-2.43; P = .0009), and decreased overall survival (HR, 1.69; 95% CI, 1.19-2.415; P = .003). Collectively, our results suggest that the use of ATG could be detrimental, especially if given too close to graft infusion in adults undergoing UCBT following Cy/Flu/TBI200 regimen.

Comparison of the Clinical Outcomes between Anti-thymocyte Globulin and Basiliximab Induction Therapy in Deceased Donor Kidney Transplantation: Single Center Experience

Background: The aim of this study is to evaluate the clinical outcomes between anti-thymocyte globulin (ATG) and basiliximab induction in deceased donor kidney transplantation (DDKT). Methods: Between May 2006 and February 2015, 40 patients underwent DDKT at our institution. Three cases (7.5%) of them were lost during the following-up schedule. In this study, ATG induction criteria were donor age >50 years old or donor creatinine level >1.3 mg/dL except hepatitis B virus positive and hepatitis C virus positive recipients. Recipients were divided into two groups: the ATG group (n=20) and the basiliximab group (n=17). Results: The 1-year patient survival in the ATG group was 89.4% compared to 93.8% in the basiliximab group (P=0.989). Graft survival for a 1 year in the ATG and the basiliximab group was 89.1% and 93.8%, respectively (P=0.967). Incidences of acute rejection episodes were more prevalent in the basiliximab group (15.0% vs. 29.4%, P=0.428). The glomerular filtration rate level by period of recipients was not different in both group (12th month, 64.60±16.17 mg/dL vs. 68.51±18.60 mg/dL, P=0.544). The overall complications during the follow-up were not significantly different in both groups (90.0% vs. 76.5%, P=0.383). Conclusions: The results showed that there was no difference in the patient survival and graft survival between induction of ATG and basiliximab of the DDKT were not different. Therefore, use of both induction agents led to a good patient and graft survival and ATG might be a safe and preferable agent for relatively poor renal function of donor in kidney transplantation.

Induction with anti-thymocyte globulin in heart transplantation is associated with better long-term survival compared with basiliximab

The use of induction therapy may reduce the risk of acute rejection after heart transplantation. This study assessed the association between basiliximab (BAS) vs anti-thymocyte globulin (ATG) induction and long-term survival after heart transplantation. We used data from the International Society for Heart and Lung Transplantation Registry to examine outcomes of all adult heart transplant recipients treated with ATG or BAS as induction therapy. We identified 9,324 transplantations performed between 2000 and 2011 whose recipients received ATG (n = 6,144) or BAS (n = 3,180). The ATG group had a higher panel reactive antibody class 1 (7.5% vs 6.1%; p < 0.018) and class 2 (6.6% vs 3.7%; p < 0.001), respectively, whereas the BAS group was less likely to have non-ischemic cardiomyopathy but more likely to be in the intensive care unit pre-transplant. One-year survival was similar for both groups, 90% vs 91% (p = 0.858). However, use of BAS was associated with poorer long-term survival compared with ATG at 5 years (77% vs 82%, p = 0.005) and at 10 years (64% vs 67%, p = 0.007). In multivariable Cox model, use of BAS remained associated with increased mortality over a median follow-up of 3.0 years (range, 0-12 years), with a hazard ratio of 1.22 (95% confidence interval, 1.09-1.37; p < 0.001). Sub-group analyses showed BAS was not independently associated with increased risk in those who received a previous transplant or in those who underwent re-transplantation due to graft failure. In the International Society for Heart and Lung Transplantation Registry experience, use of ATG rather than BAS as induction therapy appears to be associated with better long-term survival. A prospective study is necessary to confirm these findings.

Interleukin-2 receptor antagonist compared with antithymocyte globulin induction therapy in kidney transplantation from donors after cardiac death.

The aim of this study was to compare the efficacy and safety of induction therapy using the interleukin-2 receptor antagonist (IL-2RA) with antithymocyte globulin (ATG) under a tacrolimus-based immunosuppression regimen in kidney transplantation from donors after cardiac death. It was a single-centre, retrospective, cohort study design to evaluate the efficacy and safety of IL-2RA vs. ATG induction therapy in adult renal transplant recipients from donors after cardiac death. The primary end-point was the incidence of biopsy-proven acute rejection (BPAR) at 6 months, and the secondary end-point included the incidence of delayed graft function (DGF), the renal function, and the patient and graft survival at 6 months. The safety end-point was the incidence of infectious complications. A total of 132 patients (n = 37 in the IL-2RA group and n = 95 in the ATG group) were enrolled from March 2013 to April 2014. The BPAR at 6 months was similar between the two groups (IL-2RA vs. the ATG group, 5.4% vs. 12.6%, respectively, p = 0.228). There were no differences in the DGF, renal function at 1 and 3 months, and the patient and graft survival at 6 months between the two groups, but the renal function at 6 months in the IL-2RA group was superior to that of the ATG group (p = 0.02). The IL-2RA group experienced less infection than the ATG group (p = 0.025). The efficacy of IL2-RA and ATG induction under a tacrolimus-based immunosuppression regimen in low-risk DCD transplantation did not differ, but the safety of the IL2-RA induction was better than that of the ATG induction.

Unrelated cord blood transplantation vs. related transplantation with HLA 1-antigen mismatch in the GVH direction.

The donor selection superiority of HLA 1-antigen mismatched related donor versus unrelated cord blood (UCB) is an important issue for patients without an HLA-matched related or unrelated donor. Using Japanese registry data, we analyzed patients with leukemia and myelodysplastic syndrome who received transplantation using UCB or from a related donor with 1-antigen mismatch in the graft-versus-host (GVH) direction (RD/1AG-MM-GVH). Compared to the UCB group, neutrophil engraftment was significantly faster, and the incidences of acute and chronic GVHD were significantly higher in the RD/1AG-MM-GVH group. As a result, there was no significant difference in overall survival between transplantation using the RD/1AG-MM-GVH and UCB. However, the HLA-B-antigen mismatched group showed significantly inferior overall survival. The RD/1AG-MM-GVH group using anti-thymocyte globulin (ATG) showed neutrophil engraftment comparable to that of the non-ATG group and a GVHD incidence similar to that of the UCB group, which resulted in a better overall survival rate in the ATG than in the UCB group. In particular, the adverse effects of HLA-B mismatch were not observed in the ATG group. RD/1AGMM-GVH transplantation using ATG could potentially improve outcomes, and a prospective study of RD/1AGMM-GVH transplantation using low-dose ATG is currently ongoing.

Comparison of Conditioning Regimens with or without Antithymocyte Globulin for Unrelated Cord Blood Transplantation in Children with High-Risk or Advanced Hematological Malignancies

The role and potential efficacy of antithymocyte globulin (ATG) in patients receiving cord blood transplantation (CBT) remain controversial. We retrospectively evaluated the effect of ATG on patient outcomes in 207 children with high-risk or advanced hematological malignancies at 8 child blood disease centers in China. The cumulative incidence of platelet recovery on day 100 was significantly lower in the ATG cohort compared with the non-ATG cohort (77.3% versus 89.8%) (P = .046). There was no significant difference in the incidence of grade II to IV acute and chronic graft-versus-host disease (GVHD), and transplantation-related mortality (TRM) between the 2 groups (P = .76, P = .57, and P = .46, respectively). The incidence of CMV infection was significantly higher among the ATG group compared with that among the non-ATG group (P = .003). The 5-year cumulative incidence of relapse was significantly higher in the ATG cohort (30.7% versus 15.4%) (P = .009). Overall survival in the non-ATG group was slightly higher than that of the ATG cohort (64.1% versus 52.1%, P = .093) and leukemia-free survival in the non-ATG cohort was significantly higher than in the ATG cohort (56.6% versus 37.7%, P = .015). Our study demonstrated that, for high-risk or advanced childhood hematological malignancies receiving unrelated CBT, patients who received conditioning that omitted ATG had a faster platelet recovery, a comparable GVHD and TRM, a significantly lower relapse risk, and an improved long-term survival compared with those patients who received ATG in the conditioning.

Impact of Serotherapy on Immune Reconstitution and Survival Outcomes after Stem Cell Transplantations in Children: Thymoglobulin Versus Alemtuzumab

Abstract The outcome of allogeneic hematopoietic stem cell transplantation (HSCT) is strongly affected by the kinetics of reconstitution of the immune system. This study compared the effects of antithymocyte globulin (ATG) and alemtuzumab on various outcome parameters after HSCT. The study cohort consisted of 148 children, with a median age of 9.6 years (range, .4 to 19.0), who underwent HSCT for malignant and benign hematological disorders in a single HSCT unit. Conditioning included ATG (n = 110) or alemtuzumab (n = 38). Cox proportional hazard regression analysis showed that alemtuzumab significantly delayed the recovery of CD3+ T cells and CD4+as well as CD8+ T cell subsets (P ≤ .001) and natural killer (NK) cells (P = .008) compared with ATG. In both ATG- and alemtuzumab-treated patients, shorter drug exposure lead to significantly faster recovery of T cells. Alemtuzumab was associated with lower donor chimerism 3 and 6 months after transplantation and a higher risk of disease relapse (P = .001). The overall survival and event-free survival risks were significantly lower for alemtuzumab-treated patients (P = .020 and P

Clinical Comparison of Non-Myeloablative Conditioning with Anti-Thymocyte Globulin and Fludarabine for Patients with Hematologic Malignancies

BackgroundThe influence of different non-myeloablative conditioning regimens on clinical outcome remains undefined.Material/MethodsWe retrospectively analyzed the hematopoietic reconstitution, graft-versus-host disease (GVHD), and quality of life (QOL) in 56 patients with hematologic malignancies who underwent non-myeloablative stem cell transplantation (NST) with a conditioning regimen based on anti-thymocyte globulin (ATG), followed by donor lymphocyte infusion (n=24), or Fludarabine (FLU) (n=32). Hematopoietic stem cells were derived from low-resolution HLA-matched identical sibling donors.ResultsThe blood type transformation and platelet reconstitution presented significantly earlier in the FLU group than the ATG group (P<0.05). Within 100 days post-transplantation, the incidence of grade I–IV acute GVHD was significantly lower in the ATG group than the FLU group (P<0.05). After 100 days post-transplant, extensive chronic GVHD (cGVHD) was more prevalent in the ATG group than the FLU group (P<0.05). There were lower cumulative risk of relapse and higher non-relapse-related mortality in the ATG group, but better QOL in the FLU group within 24 months, and no difference in 3-year disease-free survival (DFS) or overall survival (OS) between the 2 groups (P>0.05).ConclusionsThe FLU-based conditioning regimen improved hematopoietic reconstitution and decreased extensive cGVHD, but there was no difference in 3-year DFS or OS between the 2 groups.

Perioperative effects of high doses of intraoperative thymoglobulin induction in liver transplantation.

To describe our single-centre experience in liver transplantation (LT) with the infusion of high perioperative thymoglobulin doses. The optimal dosage and timing of thymoglobulin(®) [antithymocyte globulin (ATG)] administration during LT remains controversial. Cytokine release syndrome, haemolytic anaemia, thrombocytopenia, neutropenia, fever and serum sickness are potential adverse effects associated with ATG infusion. Between December 2009 and December 2010, 16 adult non-randomized patients (ATG group), receiving a liver graft from a deceased donor, received an intraoperative infusion (4-6 h infusion) of thymoglobulin (3 mg/kg, ATG: Thymoglobuline(®)). These patients were compared (case control approach) with 16 patients who had a liver transplant without ATG treatment (control group) to evaluate the possible effects of intraoperative ATG infusion. The matching parameters were: Sex, recipient age (± 5 years), LT indication including viral status, MELD score (± 5 points), international normalized ratio and platelet count (as close as possible). The exclusion criteria for both groups included the following: Multi-organ or living donor transplant, immunosuppressive therapy before transplantation, contraindications to the administration of any thymocyte globulin, human immunodeficiency virus seropositivity, thrombocytopenia [platelet < 50000/μL] or leukopenia [white blood cells < 1000/μL]. The perioperative side effects (haemodynamic alterations, core temperature variations, colloids and crystalloids requirements, and surgical time) possibly related to ATG infusion and the thromboelastographic (TEG) evaluation of the ATG effects on coagulation, blood loss and blood product transfusion were analysed during the operation and the first three postoperative days. Intraoperative ATG administration was associated with longer surgical procedures [560 ± 88 min vs 480 ± 83 min (control group), P = 0.013], an intraoperative core temperature more than 37 °C (50% of ATG patients vs 6.2% of control patients, P = 0.015), major intraoperative blood loss [3953 ± 3126 mL vs 1419 ± 940 mL (control group), P = 0.05], higher red blood cell [2092 ± 1856 mL ATG group vs 472 ± 632 mL (control group), P = 0.02], fresh frozen plasma [671 ± 1125 mL vs 143 ± 349 mL (control group), P = 0.015], and platelet [374 ± 537 mL vs 15.6 ± 62.5 mL (control group), P = 0.017] transfusion, and a higher requirement for catecholamines (0.08 ± 0.07 μg/kg per minutes vs 0.01 ± 0.38 μg/kg per minutes, respectively, in the ATG and control groups) for haemodynamic support. The TEG tracings changed to a straight line during ATG infusion (preanhepatic and anhepatic phases) in 81% of the patients from the ATG group compared to 6.25% from the control group (P < 0.001). Patients from the ATG group compared to controls had higher post-op core temperatures (38 °C ± 1.0 °C vs 37.3 °C ± 0.5 °C; P = 0.02), an increased need of noradrenaline (43.7% vs 6.25%, P = 0.037), received more platelet transfusions (31.5% vs 0%, P = 0.04) and required continuous renal replacement therapy (4 ATG patients vs none in the control group; P = 0.10). ATG infusion was considered the cause of a fatal anaphylactic shock and of a suspected adverse reaction that led to intravascular haemolysis and acute renal failure. The side effects and the coagulation imbalance observed in patients receiving a high dosage of ATG suggest caution in the use of thymoglobulin during LT.

Impact of Antithymocyte Globulins on Patient Outcome after Myeloablative Bone Marrow Stem Cell Transplantation from HLA 10/10-Matched Unrelated Donor: A Report from the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC)

Background: A recent prospective study (Socie & al Blood 2011) demonstrated that the addition of antithymocyte globulins (ATG) to prophylaxis for graft versus host disease (GVHD) in the setting of standard myeloablative conditioning (MAC) regimen matched unrelated donor (UD) allogeneic stem cell transplantation (HSCT) resulted in a decrease in incidence of chronic GVHD without an increase of relapse or non-relapse mortality. However, stem cell source was mostly peripheral blood stem cells (PBSC) and patients (pts) were compatible at HLA-A, HLA-B, HLA-DRB1 and HLA-DQB1 (eight out of eight alleles). A retrospective study using the same setting (Mohty & al Leukemia 2012) found very similar results with donor/recipient pairs matched at 10 loci (ten out of ten alleles). However, one third of the pts received PBSC as stem cells source and 20% of the pts were transplanted with a mismatch donor (9 out of 10 alleles). We thus conducted this study to assess the impact of ATG in pts with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) transplanted with MAC using bone marrow only (BM) from matched 10/10 UD.Patients and methods: We includedall consecutive pts older than 18 years who received a first HSCT in France for AML or MDS with BM from a matched 10/10 UD after a standard conditioning regimen (fractionated total body irradiation (TBI)-Cyclophosphamide(Cy), n=106 or Endoxan-Cy, n=91) between June 2000 and June 2012. Clinical data were prospectively collected using ProMISe (Project Manager Internet Server), an internet-based data registry system shared by all centers of the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC). This study was approved by the scientific committee of the SFGM-TC.Results: A total of 197 adult pts met the criteria and were analyzed (165 AML (84%) and 35 MDS). 54 (27%) pts received ATG in the conditioning regimen whereas 143 (73%) did not. Median follow up was of 20.3 months [0.4-156]. Both groups (with or without ATG) were well balanced except for the number of CD34+ cells infused (higher in the ATG group: 3.07x106/kg [0.7-13] vs 2.71x106/kg [0.6-89] for none ATG group (p=0.03)) and GvHD prophylaxis (more likely cyclosporine plus methotrexate with ATG (94%) vs 84% without, p=0.05).The probability of acute GvHD grade II-IV was similar between both groups: 41.3% with ATG vs 49.6% without, p=0.2. Incidence rate of severe acute GVHD grade III-IV at day 100 tended to be lower in the ATG group as compared with the none ATG group (20.3% vs 9.5%, respectively, p=0.052). The cumulative incidence (CI) of chronic GVHD at 2 years was 42% in the ATG group vs 28% in the none ATG group and 37% vs 44% at 4 years, respectively (p=0.18). The probability of extensive chronic GVHD at 2 years was identical between both groups (12% with ATG vs 16% without, p=0.95).CI of non-relapse related mortality (NRM), relapse as well as disease free survival (DFS) and overall survival (OS) were similar between the 2 groups (Table 1). In multivariate analysis, advanced disease status was the only parameter associated with decreased DFS (HR 0.37, 95% CI [0.19-0.70], p=0 .02) and OS (HR 0,41, 95% CI [0,24;0,71], p<0.01). During the study, 106 pts died (28 pts (52%) in the ATG group and 78 in the none ATG group (53%)). No difference was observed in terms of cause of death (detailed in Table 2) between the two groups, relapse accounting for half the causes of in both groups (47%).Conclusion:The addition of ATG to MAC regimen in pts with AML or MDS transplanted with BM from matched 10/10 resulted in similar outcomes in terms of NRM, relapse as well as DFS and OS. Despite the limitation due to the retrospective setting of our study, we did not find any obvious benefit for adding ATG to the conditioning regimen in this setting. Prospective studies are needed to firmly answer to this question and notably to better assess a possible benefit in terms of quality of life in the ATG group.Table 1:2-years cumulative incidence of NRM, relapse, DFS and OSOutcomesATG group % [95% CI]Non ATG group % [95% CI]p valueNRM21 [15-27]23 [19-27]0.90Relapse32 [25-39]31 [27-35]0.83DFS46.9 [39.9-53.9]46.7[39.7-53.7]0.98OS57.1 [50.2-64]53[46-60]0.62Table 2:main causes of deathCauses of deathATG group n,(%)Non ATG group n,(%)Relapse13 (46.3)36 (46)GvHD3 (10.7)9 (11.5)Infection2 (7)12 (15.5)Organ toxicity5 (18)11 (14)Secondary neoplasia1 (3.6)1 (1.5)Rejection02 (2.5)Unknown4 (14.4)7 (9) DisclosuresNo relevant conflicts of interest to declare.

Myeloablative haploidentical hematopoietic stem cell transplantation using basiliximab for graft-versus-host disease prophylaxis

ObjectivesWe retrospectively compared the prophylactic effect of basiliximab and antithymocyte globulin (ATG) after haploidentical hematopoietic stem cell transplantation (HSCT) in patients with leukemia.MethodsHaploidentical HSCT using basiliximab for graft-versus-host disease (GVHD) prophylaxis in 10 patients with leukemia was retrospectively compared to ATG for GVHD prophylaxis in 24 patients.ResultsAll the patients achieved neutrophil engraftment. One patient in the ATG group did not achieve platelet engraftment. The incidence of grade II–IV and grade III–IV acute GVHD was 30 and 20%, respectively, in the basiliximab group and 16.7 and 4.2%, respectively, in the ATG group (P > 0.05). Extensive cGVHD developed in 40 and 22.2% of patients in the basiliximab group and ATG group, respectively (P > 0.05). Basiliximab resulted in mild infection and a low incidence (10%) of infection-related mortality; ATG resulted in relative severe infection with 29.2% infection-related mortality (P > 0.05). During the follow-up period, 20% of the basiliximab group and 22.7% of the ATG group relapsed (P > 0.05). In the basiliximab group and the ATG group, the 3-year accumulative overall survival rate was, respectively, 80 and 52.5% and the 3-year leukemia-free survival, respectively, was 60 and 49.6% (P > 0.05).DiscussionThe incidences of grade II–IV and grade III–IV aGVHD in the basiliximab group were similar to those in halpoidentical HSCT containing ATG. Compared to the ATG group, the basiliximab group had a lower rate of transplantation-related mortality and better long-term survival, but without statistical significance.ConclusionThe prophylactic regimen of basiliximab with haploidentical HSCT against GVHD seems safe and promising. More studies needed to verify this.

Vitamin B6 Status, Immune Response and Inflammation Markers in Kidney Transplant Recipients Treated With Polyclonal Anti-thymocyte Globulin

Background/ObjectivesVitamin B6 status has an impact on the body's inflammatory and immune responses. Immunosuppressive therapy may influence vitamin B6 metabolism in kidney transplant recipients. Treatment with polyclonal anti-thymocyte globulin (ATG) is associated with long-term changes in inflammatory and immune parameters. It is not known if ATG therapy also may have an impact on vitamin B6 status in kidney transplant recipients. We aimed to analyze the impact of therapy with ATG on vitamin B6 status, immune response, and the profile of inflammatory cytokines. Subject/MethodsThis was a retrospective, observational study that included 44 kidney allograft recipients. Twenty patients received induction therapy with ATG (6 to 24 months before enrollment). Twenty-four patients constituted the control group, matched with respect to time since transplantation. The B6 vitamers, total lymphocyte count, CD3 percentage, interleukin (IL)-6, -7, and -10, transforming growth factor β, interferon γ, and chemokine ligand 21 were analyzed in a study group. ResultsAll indicators of vitamin B6 status were lower in the ATG group than in the control group. There were also significant differences with respect to immune response (significantly lower total lymphocyte count and CD3 in the ATG group) and inflammatory status (significantly higher IL-6 and IL-10 in the ATG group). Vitamin B6 vitamers and derivatives were not related to lymphocyte count and cytokine levels or to estimated glomerular filtration rate and age of the study population. ConclusionsVitamin B6 stores and active forms are lower in kidney transplant recipients treated with ATG. ATG therapy promotes CD3 and total lymphocyte depletion and increases indicators of inflammation. We found no associations between vitamers of B6, immune response cells, and inflammatory cytokines in study population.

Renal Allograft Outcome and Infectious Complications Following Antithymocyteglobulin and Alemtuzumab Used as Induction in Kidney Transplantation.

Background: Antithymocyte globulin (ATG) and Humanized Monoclonal Anti-CD52 Antibody, Alemtuzumab (Targeted all T-cells depleting antibodies) were used as induction regimens for kidney transplantation. However, both drugs have been questionable in threatened Infectious complications which would be the main barriers to patients and allograft disease-free survival. Methods: Sixty-eight patients (Cadeveric donor 38, Living donor 30) who have been performed transplantation between July 1996 - 2009 were retrospective study analyzed kidney allograft outcome and infectious complications after induction therapy between ATG 200-400 mg, ATG 500-700 mg 1 given intravenously and alemtuzumab 30 mg given subcutaneously. Immunosuppressive agents were Tacrolimus(88.2%), Cyclosporin A(8.8%), Mycophenolate mofetil(52.9%), Azathioprine(35.2%), Everolimus(0.3%) and corticosteroids. Standard perioperative antimicrobial prophylaxis consisted of ceftriaxone in combination with Fluconazole, Trimethoprim-sulfamethoxazole and Acyclovir in high risk patients. Results: Patient and kidney graft survival at thirteen years was 95.58%. The rejection rate in low dose ATG group was 20.58%, high dose ATG was 32.14 (p-value = ns). There was no incidence of rejection in alemltuzumab group. Three grafts from ATG group were lost from rejection. The mild grade infection rate 65 events/302 patient years, moderate grade 51 event/302 patient years, severe infection 8 event/302 pateient years with no difference in terms of prevalence according to the three groups. Conclusion: ATG and alemtuzumb are effective for use as induction regimens. Infectious complications are comparable between low dose ATG, high ATG and alemtuzumab.

Comparison of different rabbit ATG preparation effects on early lymphocyte subset recovery after allogeneic HSCT and its association with EBV-mediated PTLD

Rabbit antithymocyte globulin (ATG) is commonly used before allogeneic hematopoietic stem cell transplantation (allo-HSCT) to prevent graft-versus-host disease. Studies comparing the effect of different ATG preparations and dosages on immune reconstitution and risk for Epstein-Barr virus (EBV)-mediated post-transplant lymphoproliferative disorder (PTLD) are rare. In this retrospective study, we determined T and B cell subsets by flow cytometry after allo-HSCT in children, who received ATG-Genzyme (ATG-G, n = 15), ATG-Fresenius (ATG-F, n = 25) or no-ATG treatment (n = 19). Additionally, PCR-quantified EBV-genome copy counts were correlated with incidence of PTLD. We could confirm a dose-dependent impairment of CD8(+) and CD4(+) T cell regeneration by ATG-G, including naïve and memory CD4(+) T cells. No differences were seen between the currently applied dosages of 5-10 mg/kg ATG-G and 20-60 mg/kg ATG-F. Significantly delayed T cell subset reconstitution was determined only at high dosages of 20-60 mg/kg ATG-G compared to ATG-F. B cell reconstitution was comparably impaired in ATG-G- and ATG-F-treated patients. Although the incidence of EBV reactivation was similar in both ATG groups, EBV copy counts of >10(4) copies/10(5) peripheral blood mononuclear cells and the occurrence of PTLD were only found in ATG-G-treated patients. We conclude that high, but importantly not currently applied low dosages of ATG-G, impair thymic T cell regeneration and memory T cell immunity to a greater extent than ATG-F in pediatric patients. In addition, our results suggest an increased risk for EBV-PTLD when treated with ATG-G. Prospective studies are warranted to compare different ATG preparations with regard to the immune reconstitution and EBV-PTLD.

Kinetics of peripheral blood lymphocyte subpopulations predicts the occurrence of opportunistic infection after kidney transplantation

Serial monitoring of peripheral blood lymphocyte subpopulations (PBLSs) counts might be useful in predicting post-transplant opportunistic infection (OI) after kidney transplantation (KT). PBLSs were prospectively measured in 304 KT recipients at baseline and post-transplant months 1 and 6. Areas under receiver operating characteristic curves were used to evaluate the accuracy of different subpopulations in predicting the occurrence of overall OI and, specifically, cytomegalovirus (CMV) disease. We separately analyzed patients not receiving (n = 164) or receiving (n = 140) antithymocyte globulin (ATG) as induction therapy. In the non-ATG group, a CD8(+) T-cell count at month 1 <0.100 × 10(3) cells/μl had negative predictive values of 0.84 and 0.86 for the subsequent occurrence of overall OI and CMV disease, respectively. In the multivariate Cox model, a CD8(+) T-cell count <0.100 × 10(3) cells/μl was an independent risk factor for OI (adjusted hazard ratio: 3.55; P-value = 0.002). In the ATG group, a CD4(+) T-cell count at month 1 <0.050 × 10(3) cells/μl showed negative predictive values of 0.92 for the subsequent occurrence of overall OI and CMV disease. PBLSs monitoring effectively identify KT recipients at low risk of OI, providing an opportunity for individualizing post-transplant prophylaxis practices.

Antithymocyte Globulin Is Associated With a Lower Incidence of De Novo Donor-Specific Antibodies in Moderately Sensitized Renal Transplant Recipients

Recent evidence suggests that de novo donor-specific antibodies (dnDSA) are associated with antibody-mediated rejection (ABMR) and graft failure after kidney transplantation. The effects of induction immunosuppression on dnDSA are unknown. The study population comprised 114 consecutive moderately sensitized (positive DSA and negative flow crossmatch) recipients who received deceased donor renal transplants between December 2009 and November 2011. Patients were divided into two groups based on induction immunosuppression: antithymocyte globulin (ATG) (n=85) or basiliximab (n=29) and were followed up for 36 months. Patients in the ATG group received a mean dose of 4.98 mg/kg ± 7.9 mg/kg, had a significantly higher PRA, and received more plasmapheresis and IVIG at the time of transplant. The incidence of dnDSA (P=0.02, HR=0.33, 95% CI 0.09-1.24) and ABMR (P=0.002, HR=0.2, 95% CI 0.04-0.87) was significantly lower in the ATG group. In multivariate regression analyses, ATG induction was the single most important variable associated with both ABMR and dnDSA. In moderately sensitized deceased donor renal transplant recipients, induction with ATG is associated with a reduction in the occurrence of dnDSA and ABMR when compared with basiliximab.

Comparison of rabbit antithymocyte globulin and Jurkat cell-reactive anti-t lymphocyte globulin as a first-line treatment for children with aplastic anemia

The purpose of this study was to investigate the effects of rabbit antihuman thymocyte globulin (R-ATG) and Jurkat cell-reactive anti-T lymphocyte globulin (ATG-F) in the treatment of childhood aplastic anemia (AA) and compare their efficacy and side effects. A total of 53 children with AA were analyzed in the present study, including 32 cases of severe AA, 10 cases of very severe AA and 11 cases of transfusion-dependent nonsevere AA. While receiving immunosuppressive therapy (IST), 29 and 24 patients, all of whom received long-term oral supplement with cyclosporin A (CSA), androgen, and traditional Chinese medicines, were treated with R-ATG and ATG-F, respectively. If necessary, the patients were also given supportive care such as component transfusion and/or infection control. Absolute counts of peripheral blood lymphocyte at various time points were dynamically measured after ATG therapy. According to the International AA Treatment and Effect standards, we found that there were no statistically significant differences in the response rate (70.83% vs. 68.97%, p > 0.05) and the overall survive rate (83.33% vs. 82.76%, p > 0.05) between the ATG-F and R-ATG groups. In addition, no obvious differences were observed between these two groups in the response time, efficacy in severe AA and very severe AA, or the incidence rates of ATG-related adverse reactions. After ATG treatment, the extent of peripheral blood lymphocyte reduction and duration in peripheral blood were similar between the ATG-F and R-ATG groups. The results of this study showed that ATG-F and R-ATG had similar efficacy and adverse reactions in the first-line treatment of childhood AA, despite being derived from different immunogens.

Immune Intervention for Type 1 Diabetes, 2012–2013

Immune Intervention for Type 1 Diabetes, 2012–2013