Removal of Anti-Thymocyte Globulin by Plasma Exchange in ABO-Incompatible and Positive Crossmatch Kidney Transplant Recipients.

BACKGROUND: Recipients of ABO-incompatible (ABOI) and positive crossmatch (PXM) kidney transplants are at high risk for antibody-mediated acute rejection. Despite aggressive immunosuppression in high-risk patients, the incidence of acute rejection remains considerably higher than in other groups. No published studies have examined plasma concentrations of anti-thymocyte globulin (ATG) in patients undergoing plasma exchange. The objectives of this study were to compare plasma ATG concentrations before and after plasma exchange in ABOI and PXM kidney transplant patients to determine the amount removed. MATERIALS AND METHODS: This prospective pharmacokinetic evaluation enrolled 10 patients undergoing ABOI or PXM kidney transplant at an academic medical center. Blood and waste plasma samples from 5 patients were assayed for total and active ATG concentrations. Patient records were monitored for renal function and rejection rates in the first 6 months post-transplant. RESULTS: Total ATG concentrations decreased a mean of 59.78 ± 13.91% after each plasma exchange session, and active ATG levels decreased a mean of 56.8 ± 17.08%. Mean daily concentrations reflect a lack of expected ATG accumulation. Only 1 of 4 patients had detectable ATG concentrations after 30 days. After 6 months, the incidence of acute rejection in this sample was 44% and graft survival was 89%. CONCLUSIONS: This is the first study to show that plasma exchange removes a substantial amount of ATG in high-risk kidney transplant patients. Based on these results, we believe these high-risk patients have been traditionally underdosed.

Prognostic value and dynamics of antithyroglobulin antibodies for differentiated thyroid carcinoma.

Background: The clinical value of antithyroglobulin antibodies (TgAb) as a tumor marker for differentiated thyroid cancer (DTC) is still controversial. Materials & methods: We studied 110 TgAb positive DTC patients who underwent total thyroidectomy and 131I therapies. Multivariate logistic regression was conducted to analyze the association between prognostic factors and disease outcomes. Results & conclusion: Pre-ablation TgAb levels and the changes of TgAb in 6-12 months after the first 131I therapy were risk factors for disease outcome in patients younger than 55, while extrathyroid extension was a risk factor in patients older than 55. The median TgAb half-life was 7.7 months and the median time for TgAb positivity to become negative was 15.8 months. The dynamics of TgAb within the first year after remnant ablation could predict disease outcome for DTC patients.

Relationship between rabbit anti-thymocyte globulin and development of PTLD and its aggressive form in renal transplant population.

Introduction: The aim of our study is to explore the relationship of rabbit anti-thymocyte globulin (R-ATG) on development of post-transplant lymphoproliferative disease (PTLD) and its aggressive forms (monomorphic PTLD and Hodgkin lymphoma) in renal transplant recipients.Methodology: All patients diagnosed with PTLD post-renal transplant in the United States' Organ Procurement and Transplantation Network from 2003 till 2013 and followed up till 2017 were retrospectively reviewed. Multi-variable logistic regression analysis assessed association of R-ATG to development of PTLD and its aggressive form.Results: Risk of developing PTLD post renal transplant is 1.35%. In comparison to interleukin-2 blocker induction therapy, R-ATG is associated with increased risk of development of PTLD (Odds Ratio = 1.48, confidence interval ranges from 1.04 to 2.11, p = .02) and is associated with higher risk of development of aggressive PTLD (Odds Ratio = 1.83, confidence interval ranges from 1.001 to 3.34, p = .04).Conclusion: We conclude that R-ATG induction is associated with a higher risk of PTLD and its aggressive form (monomorphic PTLD and Hodgkin lymphoma). Careful monitoring for development of PTLD in renal transplant recipients receiving R-ATG induction therapy is advised.

Analysis of Immune Cell Repopulation After Anti-thymocyte Globulin Administration for Steroid-Resistant T-cell-mediated Rejection.

BACKGROUND: Anti-thymocyte globulin (ATG) is a treatment option for steroid-resistant T-cell-mediated rejection after kidney transplantation. However, the extent to which immune-cell subsets can repopulate the peripheral blood is unknown. METHODS: Six patients with steroid-resistant T-cell-mediated rejection were recruited and underwent analysis of their immune cells for 1 year after ATG administration. Multicolor flow cytometric analysis was used to evaluate the proportions of T cells, B cells, natural killer cells, and monocytes. RESULTS: T-cell repopulation from 24% to 75% occurred in the treatment group. The major repopulated cells were effector memory CD8+ T cells followed by effector memory CD4+ T cells. The population of effector memory CD8+ T cells with low expression of interleukin-7 receptor α increased over time. The population of regulatory T cells (eg, CD8+CD28-CD56+ T cells and CD4+CD25bright T cells) increased after ATG administration. However, the populations of other immune-cell subsets, including B cells, natural killer cells, and monocytes, were not significantly altered by ATG. CONCLUSIONS: Our findings on immune cell repopulation after ATG administration will enable future studies aiming to unravel the steroid-resistance mechanism underlying T-cell-mediated rejection.

Anti-CD3 Antibody Treatment Reduces Scar Formation in a Rat Model of Myocardial Infarction.

: Introduction: Antibody treatment with anti-thymocyte globulin (ATG) has been shown to be cardioprotective. We aimed to evaluate which single anti-T-cell epitope antibody alters chemokine expression at a level similar to ATG and identified CD3, which is a T-cell co-receptor mediating T-cell activation. Based on these results, the effects of anti-CD3 antibody treatment on angiogenesis and cardioprotection were tested in vitro and in vivo. METHODS: Concentrations of IL-8 and MCP-1 in supernatants of human peripheral blood mononuclear cell (PBMC) cultures following distinct antibody treatments were evaluated by Enzyme-linked Immunosorbent Assay (ELISA). In vivo, anti-CD3 antibodies or vehicle were injected intravenously in rats subjected to acute myocardial infarction (AMI). Chemotaxis and angiogenesis were evaluated using tube and migration assays. Intracellular pathways were assessed using Western blot. Extracellular vesicles (EVs) were quantitatively evaluated using fluorescence-activated cell scanning, exoELISA, and nanoparticle tracking analysis. Also, microRNA profiles were determined by next-generation sequencing. RESULTS: Only PBMC stimulation with anti-CD3 antibody led to IL-8 and MCP-1 changes in secretion, similar to ATG. In a rat model of AMI, systemic treatment with an anti-CD3 antibody markedly reduced infarct scar size (27.8% (Inter-quartile range; IQR 16.2-34.9) vs. 12.6% (IQR 8.3-27.2); p < 0.01). The secretomes of anti-CD3 treated PBMC neither induced cardioprotective pathways in cardiomyocytes nor pro-angiogenic mechanisms in human umbilical vein endothelial cell (HUVECs) in vitro. While EVs quantities remained unchanged, PBMC incubation with an anti-CD3 antibody led to alterations in EVs miRNA expression. CONCLUSION: Treatment with an anti-CD3 antibody led to decreased scar size in a rat model of AMI. Whereas cardioprotective and pro-angiogenetic pathways were unaltered by anti-CD3 treatment, qualitative changes in the EVs miRNA expression could be observed, which might be causal for the observed cardioprotective phenotype. We provide evidence that EVs are a potential cardioprotective treatment target. Our findings will also provide the basis for a more detailed analysis of putatively relevant miRNA candidates.

Decreased iKIR-HLA C Pair Confers Worse Clinical Outcomes for Patients With Myeloid Disease Receiving Antithymocyte Globulin-Based Haploidentical Hematopoietic Stem Cell Transplantation.

Hematopoietic stem cell transplantation (HSCT) is a curative therapy for patients with malignant hematologic diseases. Killer immunoglobin-like receptor (KIR) expressed by NK cells is closely associated with the transplant outcomes, and it has been widely explored and debated for a few decades. Recently published studies have revealed that inhibitory KIRs (iKIRs) are educated by their cognate human lymphocyte antigen (HLA) ligands, and that decreased iKIR-HLA pairs post-transplantation may indicate a reduced NK cell function and impaired control of the primary disease. However, this theory still needs to be validated by additional clinical studies. Here we conducted a retrospective analysis of 246 patients who received haploidentical (haplo)-HSCT at our treatment center between January 2015 and June 2018. Our data suggests that decreased iKIR-HLA C pair post-HSCT correlated with a significantly higher risk of relapse [hazard risk (HR) = 2.95, p = 0.019] and reduced overall survival (OS) (HR = 3.74, p = 0.001) and disease-free survival (DFS) (HR = 4.05, p = 0.0004) in patients with myeloid disease. In conclusion, decreased iKIR-HLA C pair should be avoided during anti-thymocyte globulin (ATG)-based haplo-HSCT, especially for patients with myeloid disease.

Differences for T-Cell Subtypes in Aspiration Biopsies of Patients With Kidney Transplant Under Polyclonal and Monoclonal Immunosuppressive Treatments.

Thymoglobulin, or antithymocyte globulin (ATG), and anti-interleukin 2α (IL-2α) chain receptor antibody (IL-2αRAb) achieve comparable good results in kidney transplantation notwithstanding different actions on immune cells. Previously, we reported the usefulness of flow cytometry (FC) analysis of lymphocyte subsets present in peripheral blood sample (PBL) and fine-needle aspiration biopsies (FNABs) for clinical surveillance, as, FC reaches very high predictive positive values for acute rejection diagnosis. Now we report an FC study on 2 kidney transplantation (KT) groups under ATG (n = 19) and IL-2αRAb (n = 24) treatment. Both groups were further treated with calcineurin inhibitors mycophenolate mofetil (MMF) and prednisone. PBL and FNAB samples were collected on day 7 post-KT, stained for several T- and B-lymphocyte subsets, and acquired using FACScan. Statistical analysis were done by Mann-Whitney U test. FNAB results showed a significant downregulation by ATG of CD3 (P < .001), CD4 (P = .009), CD4CD29 (P = .003), and CD2 (P ≤ .001) and significant upregulation of death receptor (DR) (P = .03), CD3CD69 (P < .001), and CD3CD25 (P < .0001) as compared to groups treated with IL-2αRAb. For PBL, the same trend was seen for CD3, CD4, CD2, CD3CD25, CD3CD69, CD4CD29, and DR plus a downregulation of CD45RO (P = .001) and an upregulation of CD4CD45RA (P < .0001) in IL-2αRAb. This study shows that among stable KTs, ATG as compared to IL-2αRAb induces a significant downregulation of a subset of T-memory (CD4CD29) cells but an upregulation of antigen-experienced cells (CD45RO). Further, ATG decreases CD2, CD3, CD4, and naïve (CD45RA) and stimulates T cells as translated by CD3CD69 and DR. As it should be expected from an IL-2αRAb agent, CD25 cells were virtually eliminated.

Trough Level of Mycophenolic Acid Did Not Affect De Novo DSA Development in Kidney Transplantation.

INTRODUCTION: Mycophenolate mofetil has improved long-term outcomes of kidney transplantation. However, the impact of mycophenolic acid (MPA) trough level on the development of de novo donor-specific anti-HLA antibody (DSA) is unclear. We examined the relation between MPA trough level and de novo DSA development. METHOD: We retrospectively studied 617 kidney recipients whose MPA trough level and de novo DSA data were available. All patients underwent primary kidney transplant from living donors from 2008 to 2014, and were chronically treated with a calcineurin inhibitor, mycophenolate mofetil, and +/- steroids. They were equally divided into 4 groups according to the mean trough level of MPA (mMPA) at 1 year post-transplantation: Group 1, mMPA < 2.14 ng/mL (n = 152); Group 2, mMPA 2.14-2.83 ng/mL (n = 157); Group 3, mMPA 2.83-3.57 ng/mL (n = 153); and Group 4, mMPA ≥ 3.57 ng/mL (n = 155). The groups were compared by incidence rate of de novo DSA, graft survival rate, and renal function. RESULTS: The incidence rates of de novo DSA were 33.3% in Group 1, 23.7% in Group 2, 22.9% in Group 3, and 30.3% in Group 4 (P = .158). Although there was no significant difference in graft survival rates, a significant difference of renal functions was noted: the higher the renal function, the lower the MPA trough level. CONCLUSION: The mMPA trough level at 1 year post-transplantation was not statistically associated with the incidence rate of de novo DSA after kidney transplantation.

Induction Type and Outcomes in HLA-DR Mismatch Kidney Transplantation.

BACKGROUND: In kidney transplantation, donor recipient human leukocyte antigen (HLA)-DR mismatch signals high immunologic risk and portends inferior outcomes. We compared the impacts of depleting vs non-depleting antibody induction on the outcomes in kidney transplant recipients (KTRs) at different levels of HLA-DR mismatches. METHODS: Using the Organ Procurement and Transplantation Network/United Network for Organ Sharing database, we identified adult KTRs from 2001 to 2015 who received induction therapy with either depleting (thymoglobulin/alemtuzumab) or non-depleting (basiliximab/daclizumab) antibody and were discharged on calcineurin inhibitor/mycophenolic acid maintenance. Patients were then stratified by the number of donor-recipient HLA-DR mismatches (0, 1, 2) in both living donor (LD) and deceased donor (DD) KTRs. Under each HLA-DR mismatch category, long-term outcomes were compared for depleting vs non-depleting induction using a Cox model. RESULTS: A total of 63,821 LD (HLA-DR mismatches: 0, n = 6945 [depleting = 4409, non-depleting = 2536]; 1, n = 19,557 [depleting = 13,558, non-depleting = 6019]; and 2, n = 10,727 [depleting = 7694, non-depleting = 3033]) and 64,922 DD (HLA-DR mismatches: 0, n = 13,915 [depleting = 10,124, non-depleting = 3791]; 1, n = 27,994 [depleting = 20,454, non-depleting = 7540]; and 2, n = 23,013 [depleting = 16,908, non-depleting = 6105]) KTRs were included in the analysis. Adjusted patient death risk was significantly lower in the depleting vs non-depleting antibody induction group among DD kidney recipients (hazard ratio 0.90, 95% CI 0.85-0.96, P = .001) and trended lower among LD kidney recipients (HR 0.88, 95% 0.79-1.01, P = .05) with 2 HLA-DR mismatches. DISCUSSION: Our study found a patient survival benefit associated with the use of perioperative induction with depleting when compared to non-depleting antibody in KTRs with 2 HLA-DR mismatches and maintained on a calcineurin inhibitor/mycophenolic acid regimen.

Role of complement in patients with autoimmune hemolytic anemia and platelet transfusion refractoriness.

The complement is a key player of the innate immune response. It provides defense mechanisms that are not specific, but very efficient at neutralizing any invader, accounting for 4% of the proteins in the peripheral blood. Nevertheless, there is a dark side to the complement system, as it may activate its machinery against healthy cells such as peripheral blood red blood cells and platelets resulting in undesired hemolysis and thrombocytopenia, respectively. Understanding and identifying the role of complement in these settings allow physicians to adjust their diagnostic and therapeutic modalities accordingly. The role of complement in the pathophysiology and management of autoimmune hemolytic anemia and of alloimmune-mediated thrombocytopenia is under investigation and discussed.

Cytotoxic Effects of Rabbit Anti-thymocyte Globulin Preparations on Primary Human Thymic Epithelial Cells.

BACKGROUND: Graft-versus-host disease (GvHD) presents a major cause for morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Rabbit-derived antithymocyte globulin (rATG) treatment reduces the incidence of GvHD after allogeneic hematopoietic stem cell transplantation. However, delayed immune reconstitution following rATG treatment, partly caused by hampered thymic function, is being discussed. The present study aims at elucidating possible cytotoxic effects of 2 commonly used rATG preparations on cultured human thymic stroma, especially thymic epithelial cells (TECs). METHODS: A primary TEC culture was established and the binding and cytotoxicity of 2 rATG preparations to the aforementioned cells were assessed by flow cytometry and immunofluorescence analyses. The release of several cytokines by cultured thymic stroma cells in response to rATG was analyzed via multiplex enzyme-linked immunosorbent assays. RESULTS: Both preparations showed a comparable dose-dependent binding to TECs and exerted a similar complement-independent, dose-dependent cytotoxicity. rATG exposure further resulted in hampered secretion of interleukin (IL)-7, IL-15, and IL-6, cytokines being involved in thymic T cell development and proliferation. Pretreatment with keratinocyte growth factor diminished rATG-induced cytotoxicity of TECs and restored their IL-7 and IL-15 secretion. CONCLUSIONS: Cytotoxic effects on TECs link the rATG-induced thymic damage to the delayed T cell reconstitution, witnessed after rATG treatment. Our data support a combination treatment of rATG and thymus-protective strategies such as keratinocyte growth factor to simultaneously offer sufficient GvHD prophylaxis and overcome delayed T cell reconstitution caused by thymic damage.

Different impact of rATG induction on CMV infection risk in D+R- and R+ KTRs.

BACKGROUND: Rabbit antithymocyte globulin (rATG) induction is associated with profound immunosuppression, leading to a higher risk of cytomegalovirus (CMV) infection compared with anti-interleukin 2 receptor antibody (anti-IL-2RA). However, this risk, depending on the baseline CMV serological recipient/donor status, is still controversial. METHODS: The CMV DNAemia-free survival between rATG- and anti-IL-2RA-treated patients was analyzed in donor-positive/recipient-negative (D+R-) and recipient-positive (R+) patients in 1 discovery cohort of 559 kidney transplant recipients (KTRs) and 2 independent cohorts (351 and 135 kidney KTRs). The CMV-specific cell-mediated immunity (CMI) at baseline and at different time points after transplantation was assessed using an interferon γ enzyme-linked immunosorbent spot assay. RESULTS: rATG increased the risk of CMV DNAemia in R+ but not in D+R- KTRs. In R+ CMI-positive (CMI+) patients, the CMV DNAemia rate was higher in rATG-treated than in anti-IL-2RA-treated patients; no difference was observed among R+ CMI-negative (CMI-) patients. Longitudinal follow-up demonstrated a deeper depletion of preformed CMV CMI in R+ rATG-treated patients. CONCLUSIONS: D+R- KTRs have the highest risk of CMV DNAemia, but rATG adds no further risk. Among R+ KTRs, we described 3 groups, the least prone being R+CMI+ KTRs without rATG, then R+CMI+ KTRs with rATG, and finally R+CMI- KTRs. CMV serostatus, baseline CMV-specific CMI, and induction therapy may lead to personalized preventive therapy in further studies.

Epstein-Barr Virus and Monoclonal Gammopathy of Clinical Significance in Autologous Stem Cell Transplantation for Multiple Sclerosis.

INTRODUCTION: Autologous hematopoietic stem cell transplantation (AHSCT) with anti-thymocyte globulin (ATG) conditioning as treatment of active multiple sclerosis (MS) is rapidly increasing across Europe (EBMT registry data 2017). Clinically significant Epstein-Barr virus reactivation (EBV-R) following AHSCT with ATG for severe autoimmune conditions is an underrecognized complication relative to T-cell deplete transplants performed for hematological diseases. This retrospective study reports EBV-R associated significant clinical sequelae in MS patients undergoing AHSCT with rabbit ATG. METHODS: Retrospective data were analyzed for 36 consecutive MS-AHSCT patients at Kings College Hospital, London. All patients routinely underwent weekly EBV DNA polymerase chain reaction monitoring and serum electrophoresis for monoclonal gammopathy (MG or M-protein). EBV-R with rising Epstein-Barr viral load, M-protein, and associated clinical sequelae were captured from clinical records. RESULTS: All patients had evidence of rising EBV DNA-emia, including 7 who were lost to long-term follow-up, with a number of them developing high EBV viral load and associated lymphoproliferative disorder (LPD). Nearly 72% (n = 18/29) developed de novo MG, some with significant neurological consequences with high M-protein and EBV-R. Six patients required anti-CD20 therapy (rituximab) with complete resolution of EBV related symptoms. Receiver operating characteristics estimated a peak EBV viremia of >500 000 DNA copies/mL correlated with high sensitivity (85.5%) and specificity (82.5%) (area under the curve: 0.87; P = .004) in predicting EBV-R related significant clinical events. CONCLUSION: Symptomatic EBV reactivation increases risk of neurological sequelae and LPD in MS-AHSCT. We recommend regular monitoring for EBV and serum electrophoresis for MG in MS patients in the first 3 months post-AHSCT.

Differential Elimination of Anti-Thymocyte Globulin of Fresenius and Genzyme Impacts T-Cell Reconstitution After Hematopoietic Stem Cell Transplantation.

Anti-thymocyte globulin (ATG) is a lymphocyte depleting agent applied in hematopoietic stem cell transplantation (HSCT) to prevent rejection and Graft-vs.-Host Disease (GvHD). In this study, we compared two rabbit ATG products, ATG-Genzyme (ATG-GENZ), and ATG-Fresenius (ATG-FRES), with respect to dosing, clearance of the active lymphocyte binding component, post-HSCT immune reconstitution and clinical outcome. Fifty-eigth pediatric acute leukemia patients (n = 42 ATG-GENZ, n = 16 ATG-FRES), who received a non-depleted bone marrow or peripheral blood stem cell graft from an unrelated donor were included. ATG-GENZ was given at a dosage of 6-10 mg/kg; ATG-FRES at 45-60 mg/kg. The active component of ATG from both products was cleared at different rates. Within the ATG-FRES dose range no differences were found in clearance of active ATG or T-cell re-appearance. However, the high dosage of ATG-GENZ (10 mg/kg), in contrast to the low dosage (6-8 mg/kg), correlated with prolonged persistence of active ATG and delayed T-cell reconstitution. Occurrence of serious acute GvHD (grade III-IV) was highest in the ATG-GENZ-low dosage group. These results imply that dosing of ATG-GENZ is more critical than dosing of ATG-FRES due to the difference in clearance of active ATG. This should be taken into account when designing clinical protocols.

Naive and Stem Cell Memory T Cell Subset Recovery Reveals Opposing Reconstitution Patterns in CD4 and CD8 T Cells in Chronic Graft vs. Host Disease.

The success of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of hematological malignancies remains hampered by life-threatening chronic graft vs. host disease (cGVHD). Although multifactorial in nature, cGVHD has been associated with imbalances between effector and regulatory T cells (Treg). To further elucidate this issue, we performed a prospective analysis of patients undergoing unrelated donor allo-HSCT after a reduced intensity conditioning (RIC) regimen containing anti-thymocyte globulin (ATG) and the same GVHD prophylaxis, at a single institution. We studied T cell subset homeostasis over a 24-month follow-up after HSCT in a comparative analysis of patients with and without cGVHD. We also quantified naive and memory T cell subsets, proliferation and expression of the apoptosis-related proteins Bcl-2 and CD95. Finally, we assessed thymic function by T cell receptor excision circle (TREC) quantification and T cell receptor (TCR) diversity by TCRVß spectratyping. While the total number of conventional CD4 (Tcon) and CD8 T cells was similar between patient groups, Treg were decreased in cGVHD patients. Interestingly, we also observed divergent patterns of Naive and Stem Cell Memory (SCM) subset recovery in Treg and Tcon compared to CD8. Patients with cGVHD showed impaired recovery of Naive and SCM Tcon and Treg, but significantly increased frequencies and absolute numbers of Naive and SCM were observed in the CD8 pool. Markedly increased EMRA CD8 T cells were also noted in cGVHD. Taken together, these results suggest that Naive, SCM and EMRA CD8 play a role in the emergence of cGHVD. Reduced Naive and recent thymic emigrant Tcon and Treg in cGVHD was likely due to impaired thymic output, as it was accompanied by decreased CD4 TREC and TCR diversity. On the other hand, CD8 TCR diversity was similar between patient groups. Furthermore, no correlation was observed between CD8 TREC content and Naive CD8 numbers, suggesting limited thymic production of Naive CD8 T cells in patients after transplant, especially in those developing cGVHD. The mechanisms behind the opposing patterns of CD4 and CD8 subset cell recovery in cGVHD remain elusive, but may be linked to thymic damage associated with the conditioning regimen and/or acute GVHD.

Markers of graft microvascular endothelial injury may identify harmful donor-specific anti-HLA antibodies and predict kidney allograft loss.

Graft microvasculature is a major target of donor-specific antibodies (DSA) and endothelial damage is direct evidence of antibody-mediated rejection (ABMR). Using immunohistochemistry, we analyzed the expression of three microvascular endothelial activation markers (fascin, vimentin, and hsp47), suggestive of endothelial-to-mesenchymal transition (EndMT) in 351 graft biopsies from 248 kidney recipients, with concomitant screening of circulating antihuman leukocyte antigen (HLA) DSA at the time of the biopsy. The factors associated with EndMT marker expression were DSA and the presence of microvascular inflammation (MI). EndMT expressing grafts had significantly more allograft loss compared to EndMT negative grafts (P < .0001). The expression of EndMT markers positively correlated with anti-HLA DSA class II mean fluorescence intensity (MFI) levels and especially identified DQ and DR antibodies as being more closely associated with microvascular injury. Moreover, only DSA linked to positive EndMT score affected allograft survival, regardless of DSA MFI levels or presence of C4d deposition. Thus, EndMT markers could represent a clinically relevant tool for early identification of ongoing endothelial injury, harmful DSA, and patients at high risk for allograft failure.

Acute GVHD prophylaxis plus ATLG after myeloablative allogeneic haemopoietic peripheral blood stem-cell transplantation from HLA-identical siblings in patients with acute myeloid leukaemia in remission: final results of quality of life and long-term outcome analysis of a phase 3 randomised study.

BACKGROUND: We previously showed that human anti-T-lymphocyte globulin (ATLG) plus ciclosporin and methotrexate given to patients with acute leukaemia in remission, having allogeneic haemopoietic stem-cell transplantation with peripheral blood stem cells from an HLA-identical sibling donor after myeloablative conditioning, significantly reduced 2-year chronic graft-versus-host disease (cGVHD) incidence and severity, without increasing disease relapse and infections, and improves cGVHD-free and relapse-free survival (cGRFS). The aim of an extended follow-up study was the assessment of long-term outcomes, which are, in this context, scarcely reported in the literature. We report unpublished data on quality of life (QoL) from the original study and the results of a follow-up extension. METHODS: In the original open-label study, patients with acute myeloid and lymphoblastic leukaemia in first or subsequent remission, having sibling HLA-identical allogeneic peripheral blood stem-cell transplantation, were randomly assigned (1:1) to receive ATLG plus standard GVHD prophylaxis with ciclosporin and short-term methotrexate (ATLG group) or standard GVHD prophylaxis without ATLG (non-ATLG group). Conditioning regimens were cyclophosphamide 120 mg/kg with either total body irradiation (12 Gy) or busulfan (12·8 mg/kg intravenously or 16 mg/kg orally), with or without etoposide (30-60 mg/kg). Randomisation was stratified according to centre and disease risk. The primary endpoint was cumulative incidence of cGVHD at 2 years. The primary and secondary endpoints, excluding QoL, have been published. QoL, assessed using European Organisation for Research and Treatment of Cancer QLQ-C30 and QLQ-HDC29 questionnaires, was an unpublished secondary endpoint, which we now report here. A follow-up extension was then done, with the primary endpoint cumulative incidence of cGVHD. Enrolment has been completed for both studies. The original trial (number, NCT00678275) and follow-up extension (number, NCT03042676) are registered at ClinicalTrials.gov. FINDINGS: In the original study, from Dec 14, 2006, to Feb 2, 2012, 161 patients were enrolled and 155 were randomly assigned to either the ATLG group (n=83) or to the non-ATLG group (n=72). In the follow-up study, which started on Feb 7, 2017, and was completed on June 30, 2017, 61 patients were included in the ATLG group and 53 were included in the non-ATLG group. Global health status showed a more favourable time course in the ATLG group compared with the non-ATLG group (p=0·02; treatment by visit interaction). ATLG was descriptively superior to non-ATLG at 24 months for physical function (points estimate -14·8 [95% CI -26·4 to -3·1]; p=0·014) and social function (-19·1 [-38·0 to -0·2]; p=0·047), gastrointestinal side-effects (8·8 [2·5-15·1]; p=0·008) and effect on family (13·5 [1·2-25·8]; p=0·032). Extended follow-up (median 5·9 years [IQR 1·7-7·9]) confirmed a lower 5-year cGVHD incidence (30·0% [95% CI 21·4-41·9] vs 69·1% [59·1-80·1]; analysis for entire follow-up, p<0·001), no increase in relapses (35·4% [26·4-47·5] vs 22·5% [14·6-34·7]; p=0·09), improved cGRFS (34·3% [24·2-44·5] vs 13·9% [7·1-22·9]; p=0·005), and fewer patients still in immunosuppression (9·6% vs 28·3%; p=0·017) in the ATLG group compared with the non-ATLG group. 5-year overall survival, relapse-free survival, and non-relapse mortality did not differ significantly between groups. INTERPRETATION: The addition of ATLG to standard GVHD prophylaxis improves the probability of surviving without disease relapse and cGVHD after myeloablative peripheral blood stem-cell transplantation from an HLA-identical sibling donor for patients with acute leukaemia in remission. Further additional benefits are better QoL and shorter immunosuppressive treatment compared with standard GVHD prophylaxis without ATLG. Therefore, in this setting, ATLG plus standard GVHD prophylaxis should be preferred over the standard GVHD prophylaxis alone. FUNDING: Neovii Biotech.

Pretransplant C3d-Fixing Donor-Specific Anti-HLA Antibodies Are Not Associated with Increased Risk for Kidney Graft Failure.

Background Complement-fixing antibodies against donor HLA are considered a contraindication for kidney transplant. A modification of the IgG single-antigen bead (SAB) assay allows detection of anti-HLA antibodies that bind C3d. Because early humoral graft rejection is considered to be complement mediated, this SAB-based technique may provide a valuable tool in the pretransplant risk stratification of kidney transplant recipients.Methods Previously, we established that pretransplant donor-specific anti-HLA antibodies (DSAs) are associated with increased risk for long-term graft failure in complement-dependent cytotoxicity crossmatch-negative transplants. In this study, we further characterized the DSA-positive serum samples using the C3d SAB assay.Results Among 567 pretransplant DSA-positive serum samples, 97 (17%) contained at least one C3d-fixing DSA, whereas 470 (83%) had non-C3d-fixing DSA. At 10 years after transplant, patients with C3d-fixing antibodies had a death-censored, covariate-adjusted graft survival of 60%, whereas patients with non-C3d-fixing DSA had a graft survival of 64% (hazard ratio, 1.02; 95% confidence interval, 0.70 to 1.48 for C3d-fixing DSA compared with non-C3d-fixing DSA; P=0.93). Patients without DSA had a 10-year graft survival of 78%.Conclusions The C3d-fixing ability of pretransplant DSA is not associated with increased risk for graft failure.

Intravenous Immunoglobulin and Rituximab in HLA Highly Sensitized Kidney Transplant Recipients.

INTRODUCTION: HLA-sensitized patients are penalized both in the access to kidney transplantation (KT) and, once transplanted, in the incidence of rejections and long-term allograft survival despite aggressive induction and maintenance therapy. METHODS: This study retrospectively evaluates the impact of combining T- and B-cell-depleting agents and intravenous immunoglobulin for induction therapy in 45 highly sensitized KT patients (anti-panel reactive antibodies >60%, positive flow cytometry crossmatch or donor specific antibodies at the time of transplantation). The outcome data included the occurrence of biopsy-proven acute rejection, new-onset proteinuria, development of leukopenia, incidence of poliomavirus infection (BK or JC virus), fungal or bacterial infection after KT, de novo neoplasia, graft function, graft loss, or death with functioning KT. RESULTS: The average panel reactive antibody was 62.5%; 41 patients (91.1%) had ≥3 HLA mismatches with the donor and 91.1% of patients had class I or II anti-HLA antibodies. Fourteen patients (31.1%) presented pre-KT donor-specific antibodies and 6 patients (13.3%) had a positive flow cytometry cross-match at the time of transplantation. The incidence of acute rejection in the first 6 months was 24.4% and the cumulative incidence was 37.8%. Two patients were diagnosed with leukopenia in the first 6 months after KT. Two patients (4.5%) had cytomegalovirus disease, 17 patients (37.8%) were diagnosed with bacterial infections. Cutaneous neoplasms were identified in 5 patients (11.1%) and solid tumors in 4 (8.9%). The death-censored graft survival was 100% in the first 6 months and 93.5% at the last evaluation. Patient survival in the same periods was 97.8% and 93.3%, respectively. CONCLUSIONS: Induction immunosuppressive therapy with intravenous immunoglobulin and rituximab is effective; outcomes demonstrate an excellent patient and allograft survival and allograft function over the follow-up period.

Anti-HLA Antibodies After Precocious Transplantectomy by Vascular Thrombosis.

BACKGROUND: Our objective in this study was to determine the effects of early renal transplantectomy on patients and the production of anti-human leukocyte antigen (anti-HLA) antibodies. METHODS: Between January 2003 and May 2017, we analyzed a group of patients for the presence of specific HLA class I and/or II donor-specific antibodies (DSA), their panel-reactive antibodies (PRA), and the time period in which the antibodies were still detectable after transplantectomy. RESULTS: Anti-HLA antibodies were detected in 60.8% of patients, 60.8% and 52.2% of those patients had anti-class I and anti-class II antibodies, respectively. DSA were detected in 91.7% of the anti-HLA class I patients. Class II DSA were detected all of the patients with anti-HLA class II antibodies. The average (mean ± SD) PRA levels in our patients after transplantectomy was 60 ± 34% in class I and 63 ± 36% in class II. CONCLUSION: Anti-HLA antibodies can be detected well after transplantectomy. Even if the kidney allograft had been transplanted for only a short time, when the intensity of immunosuppression was the highest, many patients developed anti-HLA antibodies. The patients who continued with immunosuppression after transplantectomy did not develop anti-HLA antibodies.