High Risk For Graft-versus-host Disease Research Articles

Acute Graft-Versus-Host Disease After Orthotopic Liver Transplantation: Predicting This Rare Complication Using Machine Learning.

Acute graft‐versus‐host disease (GVHD) is a rare complication after orthotopic liver transplantation (OLT) that carries high mortality. We hypothesized that machine‐learning algorithms to predict rare events would identify patients at high risk for developing GVHD. To develop a predictive model, we retrospectively evaluated the clinical features of 1938 donor‐recipient pairs at the time they underwent OLT at our center; 19 (1.0%) of these recipients developed GVHD. This population was divided into training (70%) and test (30%) sets. A total of 7 machine‐learning classification algorithms were built based on the training data set to identify patients at high risk for GVHD. The C5.0, heterogeneous ensemble, and generalized gradient boosting machine (GGBM) algorithms predicted that 21% to 28% of the recipients in the test data set were at high risk for developing GVHD, with an area under the receiver operating characteristic curve (AUROC) of 0.83 to 0.86. The 7 algorithms were then evaluated in a validation data set of 75 more recent donor‐recipient pairs who underwent OLT at our center; 2 of these recipients developed GVHD. The logistic regression, heterogeneous ensemble, and GGBM algorithms predicted that 9% to 11% of the validation recipients were at high risk for developing GVHD, with an AUROC of 0.93 to 0.96 that included the 2 recipients who developed GVHD. In conclusion, we present a practical model that can identify patients at high risk for GVHD who may warrant additional monitoring with peripheral blood chimerism testing.

Abatacept for Gvhd Prophylaxis after Hematopoietic Cell Transplantation (HCT) for Pediatric Sickle Cell Disease (SCD): A Sickle Cell Transplant Advocacy and Research Alliance (STAR) Trial

Patients with severe sickle cell disease (SCD) experience organ damage, poor quality of life and premature mortality. Hematopoietic cell transplantation (HCT) is curative in SCD. Excellent outcomes have been achieved in young children with HLA matched related donors (MRD), with low rates of acute and chronic graft versus host disease (GVHD). Adolescent patients with SCD receiving MRD HCT and patients with SCD receiving matched unrelated donor (MUD) HCT, remain at highest risk for GVHD and resulting morbidity and mortality. Building on the encouraging experience with abatacept (CTLA-4Ig) for GVHD prophylaxis in URD HCT for hematologic malignancies, we launched an early phase, multicenter trial (n=25) through the Sickle Cell Transplant Advocacy and Research Alliance (STAR) of abatacept in pediatric SCD patients at high risk for GVHD. Patients with severe sickle cell disease were eligible if they were receiving a MRD HCT and either they or their donor were at least 10 years or if they were receiving a MUD HCT. Twenty-five patients have been enrolled to date with 23 patients completing conditioning and HCT. All patients received reduced intensity conditioning (RIC) with distal alemtuzumab, fludarabine, thiotepa and melphalan and marrow grafts. Four doses of abatacept (10 mg/kg/dose IV on days -1,+5,+14, +28) were added to standard GVHD prophylaxis using tacrolimus and methotrexate. Abatacept dosing was extended to eight doses for the last 11 patients (+60, +90, +120, +150). Tacrolimus was tapered at day 180 if no GHVD was present. The median age at HCT was 11 (3-21 years); 13 received a MRD HCT and 10 a MUD HCT. All patients engrafted with neutrophils at a median of 21 days (range 13-26) and platelets at a median of 23 days (13-55). As of 10/1/2019, median follow up is 804 days (range 46 – 1139). The mean myeloid and T-cell chimerisms at one (n=17) and two years (n=10) were 97.9 +/- 4.9 and 94.2 +/- 10.0 and 96.6 +/- 8.9 and 97.5 +/-4.3, respectively. Three evaluable patients at 2 years did not have chimerism studies sent. There have been 4 cases of EBV viremia (1 PTLD) and 6 cases of CMV viremia (1 disease). Grades 3-4 acute GVHD was seen in one patient and chronic/overlap in 5 patients with two patients currently receiving sytemic immune suppression. There has been no cerebral hemorrhages but one patient developed non-infectious encephalopathy of unclear etiology. The overall and sickle cell free survival at 2 years post HCT in evaluable patients (N=13) is 100% and 100%, respectively. The preliminary results in first 23 patients enrolled to date suggest that incorporating abatacept into GVHD prophylaxis is a safe and efficacious approach to improving outcomes in HCT for pediatric SCD.

P067A simple sequencing based method for identification of DPB1 resident SNP rs9277534 defining TH level of DPB1 expression

Aim Hematopoietic cell transplantation from unrelated donors carries the risk of acute graft-versus-host disease (GvHD). HLA-DPB1 matching has recently emerged as an important part of donor selection. HLA-DPB1 classification by T-cell epitope is currently used to identify permissive and non-permissive donor-recipient combinations. In addition, DPB1-linked SNP rs9277534 has been recently implicated in the severity of GvHD following transplantation with non-permissive DPB1 mismatching. Variant rs9277534A was associated in low expression, whereas rs9277534G was associated with high expression of DPB1. Recipients with the high expression variant who received transplant from DPB1-mismatched donors with low expression variant had high risk of GvHD. A simple and low-cost SNP rs9277534A/G test can assist optimal donor selection when multiple HLA suitable donors are available. Methods A simple Sanger sequencing-based method for identification of rs9277534 variants was developed. M13-tagged PCR primers were designed by applying NCBI Primer-BLAST tool to the fragment of DPB1 3’UTR containing the targeted SNP. Amplified fragments were sequenced with M13 sequencing primers. The targeted nucleotide position, n150 from the sequence start, can be visualized using any available sequencing analysis software and clearly shows the variant of SNP (“A”, “G” or “A/G”). Results Using the published list of A/G variants and a large set of samples with different combinations of DPB1 alleles, we defined a number of additional low- and high-expression DPB1 alleles. The published association of individual DPB1 alleles and rs9277534 variants was confirmed. Conclusions The extended list of low- and high-expression DPB1 alleles will provide a basis for assessing the suitability of DPB1-mismatched donors in the situation when a DPB1-matched donor is not available. The developed Sanger sequencing-based method for identification of rs9277534 variants can be used to identify the level of expression of DPB1 alleles previously not assessed.

MicroRNA-146a reduces MHC-II expression via targeting JAK/STAT signaling in dendritic cells after stem cell transplantation.

Acute Graft-versus-host disease (GVHD) is a major immunological complication after allogeneic hematopoietic cell transplantation and a better understanding of the molecular regulation of the disease could help to develop novel targeted therapies. Here we found that a G/C polymorphism within the human microRNA-146a (miR-146a) gene of transplant-recipients, which causes reduced miR-146a levels, was strongly associated with the risk of developing severe acute GVHD (n=289). In mice, deficiency of miR-146a in the hematopoietic system or transfer of recipient-type miR 146a-/- dendritic cells (DCs) enhanced GVHD, while miR-146a mimic-transfected-DCs ameliorated disease. Mechanistically, lack of miR-146a enhanced JAK2 STAT1-pathway activity, which led to higher expression of class II-transactivator (CIITA) and consecutively increased MHCII-levels on DCs. Inhibition of JAK1/2 or CIITA knockdown in DCs prevented miR-146a-/- DC-induced GVHD exacerbation. Consistent with our findings in mice, patients with the miR-146a polymorphism rs2910164 in hematopoietic cells displayed higher MHCII levels on monocytes, which could be targeted by JAK1/2-inhibition.Our findings indicate that the miR-146a polymorphism rs2910164 identifies patients at high risk for GVHD before allo HCT. Functionally we show that miR-146a acts as a central regulator of recipient-type DC activation during GVHD by dampening the pro-inflammatory JAK-STAT/CIITA/MHCII axis, which provides a scientific rationale for early JAK1/2-inhibition in selected patients.

Differential Expression of Immunity Related Genes and Early Prediction of Severe Graft Versus Host Disease after Allogeneic Hematopoietic Cell Transplantation

Background:Allogeneic hematopoietic cell transplantation (HCT) is curative for hematological malignancies. However, Graft versus host disease (GVHD) is the most common and debilitating complication of HCT as 10-15% HCT recipients die and 25% suffer long-term due to GVHD. Effective but toxic prophylaxes for GVHD (e.g., anti-thymocyte globulin) exist that can be given preemptively to patients with high risk of GVHD. However, an early and accurate identification of patients who are at a high risk of developing severe GVHD is the prerequisite for any preemptive therapy. The 'onset' of symptoms associated with GVHD is the final manifestation of a series of cellular and molecular perturbations that take place when host epithelial cells are attacked by the donor immune cells. With the aim of identifying potential functional biomarkers for early prediction of severe GVHD, a comprehensive panel of 594 genes shared among 24 immunology-related gene networks were retrospectively analyzed at different posttransplant time points prior to the onset of GVHD .Methods:Two hundred and two RNA specimens from 117 first allogeneic HCT recipients with (n=49) or without (n=68) clinically significant GVHD were analyzed. RNA was extracted from cryopreserved peripheral blood mononuclear cells (PBMNCs) collected at three early post-transplant time points: one week (n=32), one month (n=85) and two months (n=80) after transplantation. Messenger RNA counts for 594 human genes with immunity related functions and 15 internal reference genes were obtained using Nanostring based gene expression CodeSet profiling. Empirical Bayes statistics for differential gene expression, receiver operating characteristic (ROC) and principle component analyses were performed using R statistical packages to identify the gene sets with highest sensitivity and specificity for early prediction of clinically significant GVHD.Results:A 'GVHD transcript panel' comprising of highly upregulated 6 genes with T cell related pro-inflammatory functions was identified at one month post transplantation in patients with clinically significant GVHD (grade II-IV acute GVHD (median day of onset = 34 days) and/or chronic GVHD requiring systemic therapy, median day of onset = 108 days). The panel consists of CD27 (AUC=0.93; p=3.4X10-8); B- and T-lymphocyte attenuator, BTLA ((AUC=0.92; p=3.4X10-8),Inducible T-cell Co-stimulator, ICOS (AUC=0.90; p=3.5X10-7), CD5 (AUC=0.87; p=8.5X10-7), CD3D (AUC=0.88; p=8.8X10-7) and CD28 (AUC=0.91; p=9.9X10-7). The GVHD transcript panel predicted clinically significant GVHD with sensitivity of 85% and specificity of 95%.Conclusions:The findings strongly favor the early prediction of clinically significant GVHD made possible by differential expression profile of genes associated with T cell related pro-inflammatory functions The identified 'GVHD transcript panel' is highly sensitive and specific in identifying patients at a high risk of developing GVHD and can pave the way to precision HCT medicine. DisclosuresNo relevant conflicts of interest to declare.

OR41 Transcriptome analysis of immunity related genes as early predictor of graft versus host disease

Background Graft versus host disease (GVHD) is the most common and debilitating complication of allogeneic hematopoietic cell transplantation (HCT) as 10–15% HCT recipients die and 25% suffer long-term due to GVHD. Effective but toxic prophylaxes for GVHD (e.g., anti-thymocyte globulin) exist that can be given preemptively to patients with high risk of GVHD. The major barrier to this ’preemptive therapy’ is the lack of sensitive and specific assays that can identify patients at high risk of GVHD. Since allo-immune responses generated through recognition of host antigens by donor T cells culminate into GVHD, we performed the transcriptome analysis of 594 genes with immunity related functions at different posttransplant time points to predict ensuing GVHD. Methods A total of 147 RNA specimens from 65 first allo-HCT recipients were analyzed. RNA was extracted from cryopreserved PBMNCs collected at one week (n = 22), one month (n = 65) and two months (n = 60) post transplantation. Transcriptome analysis for 594 human genes with immunity related functions and 15 internal reference genes was performed using Nanostring based gene expression CodeSet profiling. Empirical Bayes statistics, receiver operating characteristic ( ROC ) and principle component analyses were performed to identify gene expression pattern predictive of GVHD. Results A ’GVHD transcript signature’ comprising of highly upregulated 6 genes with T cell related pro-inflammatory functions were identified at one month after HCT in patients with clinically significant GVHD (median day of onset = 100 days). The genes identified were CD27 (AUC = 0.93; p = 3.4X10 −8 ); B- and T-lymphocyte attenuator, BTLA (AUC = 0.92; p = 3.4X10 −8 ), Inducible T-cell Co-stimulator, ICOS (AUC = 0.90; p = 3.5X10 −7 ), CD5 (AUC = 0.87; p = 8.5X10 −7 ), CD3D (AUC = 0.88; p = 8.8X10 −7 ) and CD28 (AUC = 0.91; p = 9.9X10 −7 ). The GVHD transcript panel predicted clinically significant GVHD with sensitivity of 85% and specificity of 95%. Conclusions Early posttransplant transcript profile of genes with T cell related pro-inflammatory functions has a prominent impact on the occurrence of GVHD. The identified ‘6-genes GVHD transcript signature’ is highly sensitive and specific in early identification of patients at high risk of developing GVHD and could pave the way to precision HCT medicine.

Partial T-Cell Depletion By Low-Dose Anti-Thymocyte Globulin to Reduce Severe Acute and Chronic Graft-Versus-Host Disease after Allogeneic Stem Cell Transplantation

Background: T cells from a stem cell source are inevitably contaminated, and over 5.0×104/kg T cells are thought to induce graft-versus-host disease (GVHD) in HLA-mismatched or haplo-identical stem cell transplantations (SCTs) [4]. To suppress GVHD reactions, a procedure for T-cell depletion (TCD) was developed over the past several decades, especially for HLA-mismatched and haplo-identical SCTs, which are at high risk for GVHD. To reduce the incidence of GVHD, a potentially effective agent is anti-thymocyte globulin (ATG), which is generally administered at a dose of ≥ 5-10 mg/kg. Based on data regarding the use of ATG for the treatment of aplastic anemia, we hypothesized that ATG might accommodate engraftment and inhibit GVHD. We attempted to use a lower dose of ATG to decrease non-relapse mortality (NRM) in Japanese patients undergoing an HLA-matched SCT.Patients and method: We treated patients with hematological diseases who underwent an allogeneic SCT after March 2010 without or with 2.5 mg/kg ATG. The inclusion criteria for underlying disease included both hematological malignancies and bone marrow failures. All consecutive patients transplanted from an allogeneic related or unrelated donor were included. Cord blood transplantations were omitted from this analysis. The patients who underwent an SCT before February 2010 (n=20) were examined as the control group without ATG treatment. ATG was administered 1 day prior to the transplantation day at 2.5 mg/kg with 500 mg/body methylpredonisolone as a preconditioning procedure. GVHD prophylaxis, tacrolimus 0.03 mg/kg and short-term MTX (10-7-7 mg/m2) was adapted for both the ATG group and the control group.Results: Thirty-nine (21 male, 18 female) recipients were recruited (median age 49 yrs, range 19-64 yrs). Their underlying diseases were acute myeloid leukemia (n=14), acute lymphoblastic leukemia (n=10), myelodysplastic syndrome (n=5), lymphoma (n=7), and myeloma, aplastic anemia, and other malignancy (n=1 each). Preparation regimens were myeloablative for 17 patients (14 cyclophosphamide [CY]/total body irradiation [TBI], two busulfan [BU]/CY, and another) and non-myeloablative for the other 22 patients (14 fludarabine/melphalan [Flu/Mel] and eight Flu/BU). All but one patient achieved engraftment, and one secondary graft failure was observed. The overall incidences of acute and chronic GVHD were 63.2% and 15.8% for the ATG-treated patients (40.0% and 25.0% for the control cohort), respectively. Acute GVHD (grades II to IV and III to IV) in the recipients who received ATG occurred in 21.1% and 0.0% (control cohort, 10.0% and 5.0%), respectively. The estimated probability of overall survival (OS) 2.5 yrs after transplantation was 77.8% for the ATG group (controls, 57.1%). The relapse rate 2.5 yrs after transplantation was 21.1% and 20.0% in the ATG and control groups, respectively. The NRM rate was decreased after ATG treatment: 25.0% vs. 10.5% (not significant). The causes of mortality with or without ATG were recurrent diseases (n=1 and 2), infection (n=1 and 0), and adverse events caused by transplant-related complication (n=1 and 5), respectively. No deaths due to acute or chronic GVHD occurred.Discussion: Low-dose ATG could suppress the incidence of severe acute GVHD and chronic GVHD without increasing the NRM, although our study design did not have enough power to make a conclusion about the efficacy of low-dose ATG. However, partial T-cell depletion may be effective for HLA-matched SCT recipients. Our results show that ATG at 2.5 mg/kg can be used safely for the Japanese transplant population of HLA-matched donors. Low-dose ATG is a potential treatment to partially disempower T cells from a stem cell source, which are inevitably contaminated. Recent developments in the prophylaxis for GVHD, such as selective cytotoxic T-cell depletion by using a post-transplant CY regimen, are promising strategies to fully suppress T cells as the GVHD enhancer. Previous studies revealed the clinical efficacy of GVHD prophylaxis but did not clarify the significance of its survival benefit. Likewise, our present findings indicated a lack of survival benefit by ATG treatment in this small study. However, the low-dose ATG contributed to a reduction of severe GVHD. Although early mortality after transplantation is decreasing, late-onset comorbidity including chronic GVHD remains a significant problem. DisclosuresNo relevant conflicts of interest to declare.

Recipient Dendritic Cells Are Regulated By MiR-146a during Acute GvHD

Acute Graft-versus-host disease (GvHD) is a major immunological complication following allogeneic hematopoietic cell transplantation (allo-HCT) occurring in 30-40% of patients. Although immunosuppression with corticosteroids serves as standard first-line therapy in acute GvHD, sustained responses are achieved in less than 50% of patients. Therefore, the identification of risk factors and a better understanding of the molecular mechanisms underlying the disease are indispensable to develop novel therapeutic strategies. MicroRNAs control various key biological processes, including innate and adaptive immune responses. In particular, microRNA-146a (miR-146a) is emerging as a central regulator of innate immune cell signaling.Here we found that a G/C single nucleotide polymorphism (SNP) within the pre-miR-146a gene, which reduces the amount of miR-146a produced from the C allele, was strongly associated with the risk to develop severe acute GvHD. Patients with the rs2910164 CC genotype had a significantly higher risk to develop acute GvHD grade III-IV than all other allo-HCT recipients (P =0.002) as well as an overall increased histopathological GvHD severity. In order to functionally dissect the role of miR-146a in recipient cells during GvHD, we used gene targeted (miR-146a-/-) mice and a major histocompatibility complex (MHC)-mismatched experimental model for acute GvHD. MiR-146a deficiency of the recipient mice resulted in increased GvHD severity, elevated serum levels of pro-inflammatory cytokines and accelerated mortality compared to wild type (WT) recipients after allo-HCT. Chimeric mice with a lack of miR-146a specifically in the hematopoietic system showed an even more distinct disease exacerbation, whereas miR-146a deficiency only in non-hematopoietic recipient cells did not affect GvHD severity. Moreover, co-transplantation of recipient type miR-146a-/-dendritic cells (DCs) elicited a more aggressive course of GvHD, while overexpression of miR-146a in DCs using a specific miR-146a mimic ameliorated disease. Phenotypically, miR-146a-/- DCs displayed a more activated phenotype with increased MHC class II, CD80 and CD86 surface expression levels after endotoxin stimulation when compared to WT DCs. Global gene expression analysis revealed upregulation of the JAK-STAT signaling pathway in miR-146a-/- DCs, which we confirmed at the protein and phosphoprotein level using Western blot and flow cytometry. Importantly, inhibition of JAK-STAT signaling in DCs using the JAK1/2 inhibitor ruxolitinib prevented miR-146a-/- DC-induced GvHD exacerbation.In conclusion, our findings indicate that miR-146a acts as a central regulator of recipient type DCs during GvHD, by dampening cytokine receptor signaling via the JAK-STAT pathway. We detected the SNP rs2910164 as a marker to identify patients at high risk for GvHD before allo-HCT, facilitating the opportunity to apply pre-emptive interventions. DisclosuresNo relevant conflicts of interest to declare.

High HLA-DP Expression and Graft-versus-Host Disease

BackgroundTransplantation of hematopoietic cells from unrelated donors can cure blood disorders but carries a significant risk of acute graft-versus-host disease (GVHD). The risk is higher when the recipient and donor are HLA-DPB1–mismatched, but the mechanisms leading to GVHD are unknown. The HLA-DPB1 regulatory region variant rs9277534 is associated with HLA-DPB1 expression. We tested the hypothesis that the GVHD risk correlates with the rs9277534 allele linked to the mismatched HLA-DPB1 in the recipient.MethodsWe genotyped rs9277534 in 3505 persons to define rs9277534-DPB1 haplotypes. Among 1441 recipients of transplants from HLA-A,B,C,DRB1,DQB1–matched unrelated donors with only one HLA-DPB1 mismatch, linkage of the rs9277534 A and G alleles to the mismatched HLA-DPB1 was determined. HLA-DPB1 expression was assessed by means of a quantitative polymerase-chain-reaction assay. The risk of acute GVHD among recipients whose mismatched HLA-DPB1 allele was linked to rs9277534G (high expression) was compared with the risk among recipients whose mismatched HLA-DPB1 allele was linked to rs9277534A (low expression).ResultsThe mean HLA-DPB1 expression was lower with rs9277534A than with rs9277534G. Among recipients of transplants from donors with rs9277534A-linked HLA-DPB1, the risk of acute GVHD was higher for recipients with rs9277534G-linked HLA-DPB1 mismatches than for recipients with rs9277534A-linked HLA-DPB1 mismatches (hazard ratio, 1.54; 95% confidence interval [CI], 1.25 to 1.89; P<0.001), as was the risk of death due to causes other than disease recurrence (hazard ratio, 1.25; 95% CI, 1.00 to 1.57; P=0.05).ConclusionsThe risk of GVHD associated with HLA-DPB1 mismatching was influenced by the HLA-DPB1 rs9277534 expression marker. Among recipients of HLA-DPB1–mismatched transplants from donors with the low-expression allele, recipients with the high-expression allele had a high risk of GVHD. (Funded by the National Institutes of Health and others.)

CD45RA depletion in HLA-mismatched allogeneic hematopoietic stem cell transplantation for primary combined immunodeficiency: A preliminary study

Combined immunodeficiencies (CIDs) form a heterogeneous group of inherited conditions that affect the development, function, or both of T cells. The treatment of CIDs with allogeneic hematopoietic stem cell transplantation (HSCT) is complicated by a high incidence of life-threatening infections and an increased risk of graft-versus-host disease (GVHD). In view of the growing evidence that alloreactivity is mainly derived from human naive T cells, the selective depletion of naive T cells from allografts might constitute a way of reducing alloreactivity while maintaining memory T-cell responsiveness to pathogens. Five consecutive patients with CIDs and chronic viral infections underwent an allogeneic, HLA-mismatched HSCT. Given the patients' infection status and the potential risk of severe GVHD in the mismatched setting, the CD34(-) fraction of the allograft was depleted of naive T cells by using magnetic CD45RA beads. Engraftment occurred in 4 of the 5 patients. No severe GVHD occurred. In the 4 engrafted patients viral infections were cleared within 2 months of the HSCT, and both cellular and humoral immunity were re-established within a year of the HSCT. An early T-cell response against viral pathogens was documented in 2 patients. The present pilot study shows that clinical-grade depletion of naive T cells from an allograft through the use of magnetic CD45RA beads seems to be a feasible and efficacious option for the treatment of patients with CIDs at high risk of GVHD, infection, or both in an HLA-mismatched setting.

Low incidences of acute and chronic graft-versus-host disease after unrelated bone marrow transplantation with low-dose anti-T lymphocyte globulin

Anti-T lymphocyte globulin (ATG) is commonly used as prophylaxis for graft-versus-host disease (GVHD), especially in patients who are at high risk of GVHD. The appropriate dosage of ATG in Japan has not yet been assessed. We therefore conducted a nationwide survey of patients who received ATG-Fresenius as GVHD prophylaxis for unrelated bone marrow transplantation (uBMT). A total of 86 patients were identified (median age 31 years, range 1-68). The median total dose of ATG was 10 mg/kg. The cumulative incidence of neutrophil engraftment was 90 %. The probability of 2-year overall survival (OS) was 67 %. The cumulative incidence of 2-year non-relapse mortality was 25 %. The incidences of grade II-IV and grade III-IV acute GVHD were 20 and 8 %, respectively. The incidences of chronic and extensive chronic GVHD were 19 and 8 %, respectively. In adult patients, there was a reduction of acute GVHD with high-dose ATG (>10 mg/kg), which did not reach statistical significance. In conclusion, the addition of low-dose ATG to GVHD prophylaxis in Japanese patients who received uBMT resulted in decreased incidences of both acute and chronic GVHD without compromising OS. The effects of low-dose ATG should be assessed in a prospective clinical trial.

Shedding a new light on the HLA matching

Shedding a new light on the HLA matching

Polymorphisms in the base excision repair pathway and graft-versus-host disease

Graft-versus-host disease (GVHD) is a frequent complication after hematopoietic cell transplant (HCT). Tissue damage as a result of chemo-radiation injury is the initiating event in the pathogenesis of acute GVHD. Variations in DNA repair can influence the amount of tissue damage in response to alkylating agents and ionizing radiation used as conditioning during HCT. Since DNA damage caused by these agents is repaired by the Base Excision Repair (BER) pathway, we hypothesized that single nucleotide polymorphisms (SNPs) in BER pathway will be associated with GVHD after HCT. Hence, we analyzed 179 SNPs in BER pathway in 470 recipients of allogeneic HCT for association with acute and chronic GVHD. In multivariate analysis, one SNP (rs6844176) in RFC1 gene was independently associated with a higher risk of grade II-IV acute GVHD (RR:1.39, 95% CI:1.14-1.70, p=0.001), and showed a trend towards higher risk of grade III-IV acute GVHD (RR:1.33, 95% CI:0.95-1.85, p=0.09). One SNP in PARP1 gene (rs1805410) was associated with a higher risk of chronic GVHD (RR:1.81, 95% CI:1.29-2.54, p=0.001). These results show that SNPs in the BER pathway can be used as genetic biomarkers to predict those at high risk for GVHD towards whom novel prophylactic strategies could be targeted.

Targeting Mycophenolate Mofetil for Graft-Versus-Host Disease Prophylaxis after Allogeneic Blood Stem Cell Transplantation.

New immunosuppressive compounds are currently investigated to reduce the rate of lethal Graft-versus-Host disease (GvHD) after allogeneic hematopoietic cell transplantation without adding relevant toxicity. Although positive reports on the efficacy of Mycophenolate Mofetil (MMF) in patients with acute and chronic GvHD are available, there is only limited data on the optimal prophylactic dosing schedule in patients at high risk for GvHD. Since very low trough-levels of MPA are measured in recipients of allogeneic stem cell transplants, we performed a prospective phase I/II trial targeting daily MMF doses according to MPA AUC levels determined at several time-points after transplantation.Twenty-nine patients (18 male, 11 female) with a median age of 53 years were included. The indication for allogeneic transplantation from matched sibling (n=7) and unrelated donors (9/10 alleles matched as minimum requirement; n=22) was high-risk AML/MDS (n=19) or relapsed lymphoma/multiple myeloma (n=10). Conditioning therapy included 30 mg/m2 Fludarabine on days −9 to −6 (4 x 20 mg/m2) combined with intravenous Busulfan 3.45 mg/kg from day −5 to day −2 (4 x 3.45 mg/kg i.v.). Tacrolimus was given orally starting on day −1 at 0.03 mg/kg in order to achieve trough blood levels of 5–10 ng/ml. MMF was started on day 1 at 1500 mg intravenously every 12 hours. AUC measurements of mycophenolic acid (MPA) and its metabolite MPAG by HPLC were scheduled on day 3, 8, 14, 21 and 28 after transplantation. The MMF dose was modified in order to achieve an AUC of 35–60 μg/m*h. MMF was tapered from day 56 on, if possibleThe dose of MMF had to be increased in 15/29 (52%) patients to 1750–2500 mg every 12 hours on day 4. No patient required a reduction of dosing on day 4. With the respective dose adjustments 52% and 80% of patients reached the AUC target on day 8 and 14, respectively. There was no direct association between dose level and extramedullary toxicity. Early grade 3–4 gastrointestinal toxicity occurred in 4 patients and lead to a reduction of MMF back to 1000 mg every 12 hours. Trilineage engraftment and complete donor chimerism was observed in all patients included. Only one out seven patients with a matched related donor experienced acute GvHD > grade II. The respective proportion of grade III–IV acute GvHD in the unrelated setting was 7/20 (33%). The rate of viral (CMV) and fungal infections was not increased compared to historical controls using standard antimicrobial prophylaxis. With a median follow-up of 18 months 15 (52%) patients are alive and 14 are in complete remission. Reasons for death were relapse (n=5; 17%), pneumonia/sepsis (n=2; 7%), GvHD (n=5; 17%) and organ failure (n=2; 7%). So far, 8 out of 24 evaluable patients (33%) suffer from limited (n=3) or extensive (n=5) chronic GvHD. A retrospective analysis revealed a significant correlation between Cmax levels and the AUC for MPA. The respective target Cmax was shown to be 16 μg/ml. Given the high-risk patient population and the high proportion of unrelated donors (70%) the clinical results observed with the combination of tacrolimus and MMF as prophylactic regimen are encouraging. The regimen has to be optimised for recipients of unrelated transplants. MMF doses of up to 2500 mg every 12 hours can be infused early after stem cell transplantation without an increased risk of toxicity. A simplified MMF targeting strategy based on MPA Cmax levels seems to be warranted in future trials.

The Impact of Alemtuzumab as a Component of Conditioning Regimens on Transplantation Outcomes in a Setting of CMV-Seropositive Recipient and Donor.

Background: Graft-versus-host disease (GVHD) is one of the main issues for allogenic stem cell transplantation (SCT). Previous studies demostrated that in vivo administration of alemtuzumab (an anti-CD52 antibody) was effective to decrease the incidence of GVHD after allogenic SCT. However, due to delayed immune reconstruction, graft failure or infection is concerned. We investigated the impact of in vivo administration of alemtuzumab on the post-transplantation outcomes.Patients and methods: Thirty-five patients entered a pilot study employing allogenic SCT with alemtuzumab-containing conditioning regimen in two centers (KNUH, CNUH). We evaluated the clinical outcomes, complications and their relationship with dose of alemtuzumab.Results: The median dose of alemtuzumab was 50mg (range, 20–75) which was not adjusted on body weight and surface. All recipients (9 BM, 26 PB) and donors were CMV-seropositive before transplantion. The median survival was 14.03 months and 2 year survival rate was 47.0%. The probability of nonrelapse mortality at 90 days and 1 year was 11.4% and 22.8%, respectively. The cumulative incidence of grade II-IV acute GVHD at day 90 was 37.1%. The overall incidence of chronic GVHD was 20.8% and the incidence of extensive chronic GVHD was only 8.3%. The cumulative incidence of CMV antigenemia was 70.2%, which has been well controlled with preemptive ganciclovir treatment, and two patients with CMV antigenemia developed into CMV disease. The febrile episode was 37.1% but the duration was relatively short (median, 3 days). There were no differenecies in engraft (P = 0.573), acute and chronic GVHD (P = 0.359, P = 0.335, respectively), relapse (P = 0.849), mortality (P = 0.229), CMV antigenemia (P = 0.227) or overall survival (P = 0.51) between two groups (treated with ≥50mg of alemtuzumab vs. <50mg).Conclusion: Our study has shown that alemtuzumab is effective for GVHD prevention but correlated with high incidence of CMV antigenemia regardless of its dose. As CMV antigenemia was easily controllable with preemptive ganciclovir, the conditioning regimen containing alemtuzumab seems hopeful especially in a setting of CMV-seropositive recipient and donor with a high risk of GVHD.

Antibody response to DBY minor histocompatibility antigen is induced after allogeneic stem cell transplantation and in healthy female donors

AbstractMinor histocompatibility antigens (mHAs) recognized by donor T cells play a central role as immunologic targets of graft-versus-host disease (GVHD) and graft versus leukemia after allogeneic hematopoietic stem cell transplantation (HSCT). Men who have undergone sex-mismatched allogeneic HSCT are at high risk for GVHD because of immune responses directed against mHAs encoded by genes on the Y chromosome (termed H-Y antigens). We hypothesized that the immunogenicity of mHAs results in a coordinated response involving B cells as well as T cells. To test this, we measured antibody responses to a well-characterized H-Y antigen, dead box RNAhelicase Y (DBY), and its homolog, DBX, in 150 HSCT patients. Using Western blot and enzyme-linked immunosorbent assay (ELISA), we found that 50% of male patients who received stem cell grafts from female donors developed antibody responses to recombinant DBY protein. Antibodies to DBY were also detected in 17% of healthy women, but not in healthy men. Antibody responses were directed primarily against areas of amino acid disparity between DBY and DBX. These studies demonstrate that the immune response to mHA includes the generation of specific antibodies and suggests that the serologic response to these antigens may also be useful in the identification of new mHAs.

Treatment of relapsing leukemia after allogeneic blood stem cell transplantation by using dose-reduced conditioning followed by donor blood stem cells and GM-CSF

Ten patients with high-risk acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and myelodysplastic syndrome (MDS) relapsing early (< 1 year, n = 8) or late (> or = 1 year, n = 2) after allogeneic transplantation were treated with cytoreductive chemotherapy followed by unmanipulated peripheral blood stem cell transplantation (PBSCT) from related (n = 3) and unrelated donors (n = 7). In order to enhance the graft-versus-leukemia effect, patients received no graft-versus-host disease (GVHD) prophylaxis and granulocyte-macrophage colony-stimulating factor (GM-CSF) was given at a dose of 60 micrograms/m2 after transplant. Acute GVHD grade I-IV was seen in all patients. Eight out of ten patients achieved complete remission: one out of two patients with AML and late relapse is in good condition with limited chronic GVHD more than 1 year after the second PBSCT. The other patient died on day +171 after the second PBSCT from cerebral aspergillosis. One patient with blastic phase CML achieved molecular remission but died +330 days after the second PBSCT because of intracranial bleeding. Of the remaining five patients, three died of infectious complications on days +36, +70, and +27, one patient died with extramedullary relapse on day +35, and one from multi-organ failure in association with acute GVHD on day +32 after the second PBSCT. Two out of ten showed progressive disease and died on days +30 and +90, respectively. Although several patients achieved complete remission, the high risk of GVHD and treatment-related mortality should be kept in mind, especially when a second transplant is considered during a period of less than 12 months after the first procedure. Monitoring of minimal residual disease might predict relapse thus preventing high doses of cytotoxic drugs for reconditioning. The potential of GM-CSF to enhance the graft-versus-leukemia reactivity after cytoreductive therapy for allogeneic transplantation warrants further investigation.

Effectiveness of rotor off fraction in allogeneic murine bone marrow transplantation with complete disparity of major histocompatibility

Counterflow centrifugal elutriation (CCE) has been a highly efficient physical method for separating T cells from bone marrow (BM) without impairing cell function and yield. To investigate the usefulness of CCE, the hematopoietic potential as well as the level of T cell contamination in rotor-off (R/O) fraction of BM was studied using a murine bone marrow transplantation (BMT) model [C3H/He (H-2 k) →BALB/C (H-2 d)]. The total recovery of cells after CCE procedure was 71.4%. Morphologically, R/O fraction contained abundant mononuclear cells and a few lymphocytes. The numbers of colony forming unit for granulocyte/monocyte (CFU-GM), Sca-1 + cells, and T cells were compared among four fractions of CCE (fractions at flow rate of 17, 25, 28 mL/min, and R/O fraction). The number of CFU-GM per 10 5 nucleated cells in each fraction were significantly higher in R/O fraction (331.3 ± 34.4) compared to unfractionated marrow (UM) (21.1 ± 1.3) and fraction of 17 mL/min (FR 17) (23.7 ± 2.2 ) ( χ 2 = 0.0044 ). Neither fraction of 25 mL/min (FR 25) nor fraction of 28 mL/min (FR 28) contained CFU-GM colonies. The concentration of Sca-1 + cells in R/O fraction was significantly higher (1.96-fold) than UM ( p < 0.05), and 80.0 ± 10.1 % of Sca-1 + cells in UM were recovered in R/O fraction; 88.1% of Thy-1.2 + T cells were eliminated in R/O fraction ( p < 0.05). Mice receiving UM after lethal irradiation (875cGy) suffered from severe graft-versus-host disease (GVHD) and all five died within 7 days after BMT procedure (Group A). Of interest, mice receiving mixture of R/O fraction with lymphocyte-rich fraction (FR 25 plus FR 28) to equalize T cell number as UM, developed severe GVHD and four out of five died (probability of survival; 20%) (Group B). Mice receiving R/O fraction had mild GVHD and four out of five survived for at least 90 days (probability of survival; 80%) (Group C). In group C, probability of survival ( p = 0.0006 ) was higher, and severity of GVHD ( p = 0.0043 ) and progression rate of GVHD ( p = 0.02 ) was lower. In conclusion, the elutriated R/O fraction cells of BM have the advantages of stable engraftment and tolerable GVHD in murine allogeneic BMT with complete major histocompatibility disparity. This could be directly applicable to patients with high risk of GVHD and graft failure in upcoming clinical trials.

Use of donor T-lymphocytes expressing herpes-simplex thymidine kinase in allogeneic bone marrow transplantation: a phase I-II study.

Allogeneic bone marrow transplantation (BMT) is associated with a severe complication; graft-versus-host disease (GvHD). While effectively preventing GvHD, ex-vivo T lymphocyte marrow depletion unfortunately increases graft rejection and reduces the graft-ver-sus-leukemia (GvL) effect. The ex-vivo transfer of the herpes simplex thymidine kinase (HS-tk) suicide gene into T cells before their infusion with hematopoietic stem cells should allow for selective in vivo depletion of these T cells with ganciclovir (GCV) if subsequent GvHD was to occur. Thus, one could preserve the beneficial effects of the T cells on engraftment and tumor control in patients not experiencing severe GvHD. We have demonstrated that retroviral-mediated transfer of HS-tk and Neomycin resistance genes in T-lymphocytes followed by G418 selection results in T-cells specifically inhibited by GCV with no bystander effect. Escalating amounts of HS-tk expressing T-cells will be infused in conjunction with a T-cell depleted marrow grafts to allogeneic HLA identical leukemic recipients. Toxicity, survival, alloreactivity and GCV-sensitivity of the gene-modified cells will be monitored. Patients with leukemia undergoing an HLA-matched allogeneic BMT associated with a high risk of GvHD will be enrolled in the protocol.

Mismatches of minor histocompatibility antigens between HLA-identical donors and recipients and the development of graft-versus-host disease after bone marrow transplantation.

Graft-versus-host disease (GVHD) can be a major complication of allogeneic bone marrow transplantation even when the donor and recipient are siblings and share identical major histocompatibility antigens. The explanation may be a mismatch of minor histocompatibility antigens. We previously characterized five minor histocompatibility antigens, HA-1, 2, 3, 4, and 5, that are recognized by T cells in association with the major histocompatibility antigens HLA-A1 an A2. We collected peripheral-blood leukocytes from 148 bone marrow recipients and their sibling donors, who were genotypically HLA identical. Fifty pairs were positive for HLA-A1, 117 were positive for HLA-A2, and 19 were positive for both. The pairs were typed with cytotoxic-T-cell clones specific for minor histocompatibility antigens HA-1, 2, 3, 4, and 5. Mismatches of HA-3 were equally distributed among recipients in whom GVHD developed and those in whom it did not. By contrast, a mismatch of only HA-1 was significantly correlated with GVHD of grade II or higher (odds ratio, infinity; P = 0.02) in adults. One or more mismatches of HA-1, 2, 4, and 5 were also significantly associated with GVHD (odds ratio, infinity; P = 0.006) in adults. These associations were not observed in children. A mismatch of minor histocompatibility antigen HA-1 can cause GVHD in adult recipients of allogeneic bone marrow from HLA-identical donors. Prospective HA-1 typing may improve donor selection and identify recipients who are at high risk for GVHD.