Risk Of Severe Acute Graft-versus-host Disease Research Articles

Impact of the Type of Tyrosine Kinase Inhibitor (imatinib or dasatinib) Used Before allo-HCT on Outcome of Patients with Philadelphia-Positive Acute Lymphoblastic Leukemia. A Study on Behalf of the Acute Leukemia Working Party of the EBMT

The use of tyrosine kinase inhibitors (TKIs) during induction and consolidation, followed by allogeneic hematopoietic cell transplantation (allo-HCT), is a standard of care for patients with Philadelphia (Ph)-positive acute lymphoblastic leukemia (ALL). The goal of this study was to compare results of allo-HCT according to the type of TKI used pre-transplant, either imatinib, dasatinib or both. This was a retrospective, registry-based analysis including adult patients with Ph-positive ALL treated with allo-HCT between years 2010-2022. The analysis included 606 patients pre-treated with imatinib, 163 with dasatinib and 94 with both imatinib and dasatinib. Allo-HCTs were performed in first complete remission from either unrelated (56%), matched sibling (36%) or haploidentical donors (8%). Relapse incidence at 2 years was 26% in the imatinib group and 21% in the dasatinib group and 19% in the imatinib + dasatinib group (P = .06) while non-relapse mortality was 19%, 15%, and 23%, respectively (P = .37). No significant differences were found for leukemia-free survival (55% vs. 63% vs. 58%, P = .11) and overall survival (72% vs. 76% vs. 65%, P = .32). The incidence of grade 2-4 acute graft-versus-host disease (GVHD) and chronic GVHD was comparable across study groups, while the incidence of grade 3-4 acute GVHD was significantly increased for patients pre-treated with dasatinib alone (20%) than in the imatinib group (10%) or imatinib + dasatinib group (13%) (P = .002). On multivariate analysis a chance of GVHD and relapse-free survival (GRFS) was significantly decreased while the risk of grade 3-4 acute GVHD was increased for the dasatinib compared to imatinib group (hazard ratio, HR = 1.27, P = .048 and HR = 2.26, P = .0009, respectively). This study provides no evidence for the advantage of one TKI over another in terms of LFS and OS. However, the use of dasatinib is associated with increased risk of severe acute GVHD and decreased GRFS.

Allogeneic hematopoietic stem cell transplant outcomes in adults with inherited myeloid malignancies.

There is increasing recognition that pathogenic germ line variants drive the development of hematopoietic cancers in many individuals. Currently, patients with hereditary hematologic malignancies (HHMs) receive similar standard therapies and hematopoietic stem cell transplant (HSCT) approaches as those with sporadic disease. We hypothesize that patients with myeloid malignancies and deleterious germ line predisposition variants have different posttransplant outcomes than those without such alleles. We studied 472 patients with myeloid neoplasms, of whom 26% had deleterious germ line variants and 34% underwent HSCT. Deleterious germ line variants in CHEK2 and DDX41 were most commonly seen in American and Australian cohorts, respectively. Patients with deleterious germ line DDX41 variants had a higher incidence of severe (stage 3-4) acute graft-versus-host disease (GVHD) (38%) than recipients with deleterious CHEK2 variants (0%), other HHM variants (12%), or patients without such germ line variants (9%) (P= .002). Importantly, the use of posttransplant cyclophosphamide reduced the risk of severe acute GVHD in patients receiving HSCT for deleterious germ line DDX41-associated myeloid neoplasms (0% vs 53%, P= .03). Based on these results, we advocate the use of posttransplant cyclophosphamide when individuals with deleterious germ line DDX41 variants undergo allogeneic HSCT for myeloid malignancies, even when transplantation has been performed using wild-type donors.

Impact of broad-spectrum antibiotic exposures and multidrug-resistant gram-negative bacteremia on hematopoietic cell transplantation outcomes.

There is a close association between the use of broad-spectrum antibiotics, gut microbiome alteration, multidrug resistant (MDR) gram-negative bacilli (GNB) bacteremia, graft versus host disease (GVHD), and mortality post-allogeneic hematopoietic cell transplantation (allo-HCT). This study reports the impact of the high use of carbapenems and colistin and MDR bacteremia pre- and post-HCT on HCT outcomes. This was a single-center, partial retrospective, and prospective study from 2016 to 2020. Both pre- and post-HCT antibiotic exposures and blood culture/sensitivity were recorded. MDR GNB was defined as either non-susceptibility to third-generation cephalosporin or carbapenems. In the absence of positive cultures, the treating physician escalated antibiotics from third-generation cephalosporins to carbapenem and/or colistin as per clinical discretion. De-escalation policy was not strictly enforced. MDR GNB bacteremia was seen in 29 of 76 (38%) of patients peri-HCT. The utilization rates for carbapenems and colistin was significantly higher in the cohort with MDR GNB bacteremia pre-HCT (70%vs. 32%, p=0.002 and 31%vs. 6.4%, p=0.007, respectively) and post-HCT (100%vs. 74.5%, p=0.002, and 55.2%vs. 8.5%, p<0.0001, respectively). The cohort with MDR GNB bacteremia had significantly more severe acute GVHD at day+100 (45%vs. 17.5%, p=0.009). The median survival was 204 days compared to not reached in the cohort without any MDR GNB bacteremia (p=0.005). This study shows pre- and post-HCT MDR GNB bacteremia is associated with an increased risk of severe acute GVHD and mortality. Patients with MDR GNB bacteremia had higher exposure to pre- and post-HCT carbapenems and colistin.

Pericardial Effusion after Hematopoietic Stem Cell Transplant Is Associated with Poor Survival

<h3>Background</h3> Pericardial effusion (PE) is a rare but life-threatening complication that can occur following hematopoietic stem cell transplant (HCT). The incidence in pediatric post-HCT population has been reported to be between 9%-37%. The underlying etiology is unclear and small studies have reported high morbidity and mortality in patients who develop PE post-HCT. Various studies have attempted to analyze the risk factors associated with occurrence of PE after HCT but detailed analysis is limited due to low incidence. <h3>Methods</h3> We retrospectively analyzed the University of Minnesota's Blood and Marrow Transplant database for occurrence of PE after HCT in patients less than 18 years between January 1, 2005 and December 31, 2018. Data was analyzed to compare the overall survival (OS) in patients who developed PE with those who did not. Risk factors analyzed included age, graft versus host disease (GVHD), type of conditioning regimen, graft source, underlying disease and human leukocyte antigen matching using univariate analysis. Multivariate analysis was performed using logistic regression model. <h3>Results</h3> A total of 770 patients underwent HCT during the study period, of which 162 (21%) developed PE. The median age of transplant for patients who developed PE was 8 years with about 60% males (n=98). Median time to development of PE after HCT was 69 days. Children who developed PE post-HCT had a significantly poor survival (2-year OS of 66%, confidence interval (CI): 58-73% vs 78%, CI: 75-81% in controls; p<0.01). There was a higher risk of grade III-IV acute GVHD in the PE cohort (relative risk (RR) of 14% (CI: 8-19%) vs 4%(CI: 3-6%) in those without PE). In univariate analysis, use of myeloablative conditioning as compared to non-myeloablative or reduced intensity conditioning (RR of 24% (CI: 20-27%) vs 11% (CI: 7-16%); p<0.01), use of umbilical cord blood (UCB) stem cells compared to bone marrow or peripheral blood stem cells (RR: 24% (CI: 20-28%) vs 18% (CI: 14-21%); p<0.01), and underlying malignant disorders were significantly associated with development of PE (RR: 26% (CI: 20-31%)) and inherited metabolic disorders (RR: 23% (CI: 17-28%) vs 15% in non-malignant disorders (CI: 11-20%); p<0.01). A higher risk was also noted in those with metabolic disorders (In multivariate analysis, use of myeloablative conditioning showed a significantly higher risk of development of PE (hazard ratio of 2.16 (CI: 1.33-3.50); p<0.01). <h3>Conclusion</h3> Pericardial effusion after HCT is associated with a higher mortality and higher risk of severe acute GVHD. The high-risk group (underlying malignancy, receiving myeloablative conditioning and UCB transplant) should be monitored closely for development of PE.

Implications of HLA in allogeneic stem cell transplantation

Graft-versus-host disease (GVHD) is a major barrier to successful allogeneic stem cell transplantation. Therefore, the identification of an alternative donor with a lower risk of GVHD is important for patients lacking an HLA-identical sibling donor. To date, HLA studies of large cohorts of unrelated hematopoietic stem cell transplantation (UR-HSCT) have provided important and helpful information for donor selection. In UR-HSCT through Japan Marrow Donor Program, patient and donor HLA-A, -B, and -C, and HLA-DRB1 and -DQB1 double mismatches are significant risk factors for severe GVHD and mortality. HLA-DPB1 mismatch does not affect survival; however, it reduces the chances of leukemia relapse. In the analysis of a specific allele effect on transplant outcomes, HLA-C*14:02 was significantly associated with an increased risk of severe acute GVHD. The development of next-generation sequencing (NGS) has enabled full-length HLA allele typing. Evolutionary analysis of the entire HLA-DPB1 revealed that a highly conserved region from exon 3 to 3'UTR provoked acute GVHD that was different from a T-cell epitope mismatching algorithm, reflecting exon 2 polymorphisms. Furthermore, a recent study demonstrated the importance of full-length NGS HLA typing on UR-HSCT outcomes. The usage of NGS may provide important information on the implications of the HLA genes in allogeneic stem cell transplantation.

Unexpected High Incidence of Human Herpesvirus-6 Encephalitis after Naive T Cell–Depleted Graft of Haploidentical Stem Cell Transplantation in Pediatric Patients

The CD45RA T cell depletion (TCD) method has been used to deplete naive T cells, preventing graft-versus-host disease (GVHD) but preserving memory cells, providing immediate functional T cells with anti-infection, antileukemia, and antirejection effects. We describe a series of 25 consecutive high-risk patients with leukemia who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with CD45RA TCD. Each patient received 2 cell products: 1 created by CD34 positive selection and the other through CD45RA depletion from the CD34 negative fraction by a CliniMACS device. CD45RA-depleted haplo-HSCT was well tolerated, with rapid engraftment and low risk of severe acute GVHD and chronic GVHD. Although this treatment achieved a good control of viral reactivations, such as cytomegalovirus and adenovirus, we observed an unexpectedly high rate of limbic encephalitis due to human herpesvirus-6 (HHV-6; 8 cases). Characteristically, the infection appeared early in almost all patients, just after the engraftment. Although no patient died from encephalitis, 1 patient showed neuropsychological sequelae, and another experienced secondary graft failure just after the HHV-6 reactivation.

Impact of mismatched HLA on graft-versus-host disease in unrelated stem cell transplantation

Graft-versus-host disease (GVHD) caused by patient and donor human leukocyte antigen (HLA) mismatch is a complication of unrelated hematopoietic stem cell transplantation (UR-HSCT) that leads to reduced success rates. To date, studies on HLA alleles in transplant have provided important information on unrelated donor selection. In this study on the effects of specific HLA alleles on acute GVHD in UR-HSCT, HLA-C＊14:02 was found to be significantly associated with an increased risk of acute GVHD. Patient HLA-C＊14:02 and donor HLA-C＊15:02 mismatch was usually KIR2DL-ligand mismatch in the GVH direction in Japanese UR-HSCT cohort, and the higher risk of severe acute GVHD for KIR2DL-ligand mismatch in GVH direction demonstrated in previous Japanese UR-HSCT study was attributable to this particular mismatch combination. Recently, the risk of acute GVHD after UR-HSCT was reported to be associated with the HLA-DP expression level, which is associated with the variant rs9277534 located in the 3'untranslated region (UTR) of the HLA-DPB1 gene. We constructed phylogenetic trees of HLA-DPB1 alleles using next-generation sequencing (NGS) HLA typing data that included introns and 3'UTRs. Results reported that rs9277534 represented a highly conserved region from exon 3 to the 3'UTR, which may lead to acute GVHD via a mechanism different from that observed using T-cell epitope mismatching algorithms, perhaps reflecting exon 2 polymorphisms. The usage of innovative technologies such as NGS in genetic analysis and HLA typing thus has profound implications in this field.

Graft-versus-Host Disease after HLA-Matched Sibling Bone Marrow or Peripheral Blood Stem Cell Transplantation: Comparison of North American Caucasian and Japanese Populations

The risk of acute graft-versus-host disease (GVHD) after HLA-matched sibling bone marrow transplantation (BMT) is lower in Japanese than in Caucasian patients. However, race may have differential effect on GVHD dependent on the graft source. North American Caucasian and Japanese patients receiving their first allogeneic BMT or peripheral blood stem cell transplantation from an HLA-matched sibling for leukemia were eligible. BMT was performed in 13% of the Caucasian patients and in 53% of the Japanese patients. On multivariate analysis, the interaction term between race and graft source was not significant in any of the models, indicating that graft source does not affect the impact of race on outcomes. The risk of grade III or IV acute GVHD was significantly lower in the Japanese patients compared with the Caucasian patients (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.57 to 0.96), which resulted in lower risk of nonrelapse mortality in the Japanese patients (HR, 0.69; 95% CI, 0.54 to 0.89). The risk of relapse was also lower in this group. The lower risks of nonrelapse mortality and relapse resulted in lower overall mortality rates among the Japanese patients. In conclusion, our data indicate that irrespective of graft source, the risk of severe acute GVHD is lower in Japanese patients, resulting in a lower risk of nonrelapse mortality.

A Prospective Multicenter Study of Nonmyeloablative Conditioning with TBI or Fludarabine/TBI for HLA-Matched Related Hematopoietic Cell Transplantation for Treatment of Hematologic Malignancies with Post Grafting Immunosuppression with Tacrolimus and Mycophenolate Mofetil: 10-Year Experience

Background: Nonmyeloablative conditioning with 2-Gy TBI alone or in combination with fludarabine (FLU/TBI) and HLA-matched related donor peripheral blood allografts followed by cyclosporine (CSP) and mycophenolate mofetil (MMF) for the prophylaxis of graft-versus-host disease (GVHD) is an effective therapy for many hematologic malignancies with reliable engraftment and moderate toxicity. The major causes of non-relapse mortality (NRM) are the development of acute and chronic GVHD. Several studies have demonstrated that tacrolimus may offer advantages compared with CSP for the prevention of GVHD in patients treated with myeloablative conditioning. The combination of tacrolimus and MMF, which has been used for GVHD prophylaxis after myeloablative hematopoietic cell transplantation (HCT), was well tolerated with low toxicity. Pilot data suggested an improved and perhaps superior GVHD prophylaxis with tacrolimus/MMF compared to our extensive historical experience using CSP/MMF with nonmyeloablative HCT. The purpose of this study is to evaluate the incidence of grade III-IV and II-IV acute GVHD, extensive chronic GVHD, along with the rate of NRM, relapse/progression, and overall survival after nonmyeloablative conditioning and post-grafting immunosuppression with tacrolimus and MMF.Methods: In a phase II multicenter clinical trial we evaluated the effect of post grafting immunosuppression with tacrolimus and MMF for the prophylaxis of GVHD following nonmyeloablative conditioning with 2-Gy TBI alone or in combination with 90mg/m2 FLU (FLU/TBI) for patients with hematologic malignancies. Patients at low risk of graft rejection (preceding autologous HCT within 6 months) received TBI alone (n=50) while the remaining patients received FLU/TBI conditioning (n=100). Tacrolimus was administered orally (0.06 mg/kg, Q12 hr) from days -3 to +56 and in the absence of GVHD tapered off by day +180. Tacrolimus was targeted to 15-20 ng/ml for the first 28 days and 10-20 ng/ml subsequently while on full dose. MMF was given orally (15 mg/kg, Q12 hr) from day 0 until day 27.Results: 150 patients were enrolled from 2004 to 2013 and received peripheral blood stem cells (median doses of 8.1×106 CD34+ cells/kg and 3.5×108 CD3+ cells/kg) from HLA-matched related donors. Diagnosis at transplant included AML (n=42), ALL (n=6), CLL (n=2), MDS/MPD (n=12), NHL (n=25), HL (n=8), and MM (n=55). Median patient age was 56 (range 19-74) years. Sixty-one percent of patients had an HCT comorbidity index (HCT-CI) score of greater than 2. Five percent of patients had failed a prior autologous HCT in FLU/TBI group. Median follow-up was 5.2 years. One graft failure was observed in the FLU/TBI group and no patients rejected their graft. The early NRM at day 100 was 1%. The cumulative incidences of grade II-IV and grade III-IV acute GVHD at 120 days were 26% (FLU/TBI 25%; TBI 28%) and 4% (FLU/TBI 2%; TBI 8%), respectively. Only one patient developed grade IV acute GVHD. Forty-eight percent of patients had chronic GVHD by 5 years (FLU/TBI 44%; TBI 54%). Five-year NRM was low at 12%. The overall cumulative incidence of relapse/progression at 5 years was 52%. Five-year overall and progression-free survivals were 51% and 37%, respectively.Conclusions: Post-grafting immunosuppression and GVHD prophylaxis with tacrolimus/MMF resulted in a low risk of acute and chronic GVHD, which compares favorably with our experience in a concurrent trial using CSP/MMF with FLU/TBI conditioning (46% grades II-IV acute and 72% chronic GVHD with CSP/MMF, respectively; BBMT, 2013, 19: 1340-1347). Furthermore, we recently reported that the active metabolite of MMF (MPA) concentration at steady state (MPA Css) was lower in patients who received concomitant CSP than patients receiving tacrolimus. Low total MPA Css was associated with an increased risk of severe acute GVHD following nonmyeloablative HCT (BBMT 2013, 19: 1159-1166). Together these data warrant consideration of a randomized phase III trial to investigate the role of tacrolimus/MMF versus CSP/MMF in nonmyeloablative HCT. [Display omitted] DisclosuresMaloney:Seattle Genetics: Honoraria; Juno Therapeutics: Research Funding; Janssen Scientific Affairs: Honoraria; Roche/Genentech: Honoraria.

Amino acid substitution at peptide-binding pockets of HLA class I molecules increases risk of severe acute GVHD and mortality

AbstractHLA disparity has a negative impact on the outcomes of hematopoietic cell transplantation (HCT). We studied the independent impact of amino acid substitution (AAS) at peptide-binding positions 9, 99, 116, and 156, and killer immunoglobulin-like receptor binding position 77 of HLA-A, B, or C, on the risks for grade 3-4 acute graft-versus-host disease (GVHD), chronic GVHD, treatment-related mortality (TRM), relapse, and overall survival. In multivariate analysis, a mismatch at HLA-C position 116 was associated with increased risk for severe acute GVHD (hazard ratio [HR] = 1.45, 95% confidence interval [CI] = 1.15-1.82, P = .0016). Mismatch at HLA-C position 99 was associated with increased transplant-related mortality (HR = 1.37, 95% CI = 1.1-1.69, P = .0038). Mismatch at HLA-B position 9 was associated with increased chronic GVHD (HR = 2.28, 95% CI = 1.36-3.82, P = .0018). No AAS were significantly associated with outcome at HLA-A. Specific AAS pair combinations with a frequency >30 were tested for association with HCT outcomes. Cysteine to tyrosine substitution at position 99 of HLA-C was associated with increased TRM (HR = 1.78, 95% = CI 1.27-2.51, P = .0009). These results demonstrate that donor-recipient mismatch for certain peptide-binding residues of the HLA class I molecule is associated with increased risk for acute and chronic GVHD and death.Key Points

Impact of amino acid substitution at residue 9 of HLA-A2 on the development of acute GVHD in Korean pediatric patients receiving unrelated hematopoietic stem cell transplantation

Incompatibility of human leukocyte antigen (HLA) alleles between donors and recipients of unrelated hematopoietic stem cell transplantation (UHSCT) increases the risk of acute graft-versus-host disease (GVHD). We evaluated the positional effect of amino acid substitutions in HLA molecules on severe acute GVHD in Korean pediatric recipients of UHSCT. All of 64 donor-recipient pairs were serologically matched for HLA-A, -B, and -DR loci. Only substitution at residue 9 resulting from an HLA-A*02 polymorphism was significantly associated with the risk of severe acute GVHD in patients (OR=7.0, P=0.033) on multivariate analysis. Recipients of this mismatched HLA also showed shortened overall survival (HR=9.7, P<0.001) and increased risk for transplant-related mortality (HR=9.1, P=0.027). Structural modeling showed that the amino acid substitution could alter the peptide preference of the ligand-binding pocket. A single amino acid substitution at position 9 was a major predictor of severe acute GVHD in Korean pediatric patients.

Immunology and Gene Therapy: Shoulder to Shoulder Into the Fray: International Symposium: Critical Frontiers Between Immunity and Gene Therapy Pamplona, Spain, 27–28 October 2009

Functions of the immune system are critical for the outcome of gene therapy. Immunologists, virologists, and gene therapists met in Pamplona, Spain, in October 2009 to present and analyze common frontiers in these fields under the auspices of the Ramon Areces Foundation (http://www.fundacionareces.es). Antibodies and cell-mediated immune mechanisms can be either friends or foes in gene therapy. A form of Murphy’s law seems to apply: “If an immune response is to be induced, it will usually be weak. If an immune response is to be avoided, it will be almost always neutralizing.”

Mycophenolate mofetil combined with tacrolimus and minidose methotrexate after unrelated donor bone marrow transplantation with reduced-intensity conditioning

We evaluated the efficacy of a post-grafting immunosuppressive regimen consisting of tacrolimus, methotrexate, and mycophenolate mofetil (MMF) in 21 adults (median age, 55 years) with poor-risk hematologic malignancy who underwent unrelated bone marrow transplantation after fludarabine-based reduced-intensity conditioning (RIC). In combination with intravenous tacrolimus and minidose methotrexate (5 mg/m2 on days 1, 3, and 6), MMF was orally administered at 30 mg/kg daily in three divided doses between days 7 and 27. All patients achieved neutrophil recovery with donor-type chimerism at a median of 19 days (range, 13-35). Cumulative incidences of grades II-IV and III-IV acute graft-versus-host disease (GVHD) were 33% (95% CI, 15-53%) and 5% (95% CI, 0.3-20%), respectively. Five of 20 evaluable patients developed extensive chronic GVHD. Toxicities associated with the use of MMF were acceptable, although one patient experienced intractable GVHD immediately after the cessation of MMF. With a median follow-up of 24 months, overall survival at 3 years was 38% (95% CI, 14-63%). No late graft failure was observed. In conclusion, post-transplant MMF combined with tacrolimus and methotrexate was well tolerated and conferred stable donor cell engraftment, low risk of severe acute GVHD, and encouraging overall survival in unrelated donor marrow transplantation after RIC regimens.

Phase II study of tacrolimus and methotrexate for prophylaxis of acute graft-versus-host disease after HLA-A, B, and DRB1 genotypically mismatched unrelated bone marrow transplantation among Japanese patients

Bone marrow transplantation from unrelated donors (UR-BMT) has been considered to be effective for patients with hematological malignancies who have no suitable related donor. However, disparities of HLA between a recipient and a donor increase the risk of severe acute graft-versus-host disease (GVHD). We evaluated GVHD prophylaxis using tacrolimus and methotrexate for HLA-A, B, or DRB1 genotypically mismatched UR-BMT. Fifty-five patients were enrolled in this study. The incidence of grade III to IV acute GVHD was 23.6% for all patients. No significant difference in the incidence of grade III to IV acute GVHD was observed between HLA-A or B 1 locus mismatch transplantation (18.8%) and HLA-DRB1 1 locus mismatch transplantation (16.7%) (P = 0.96). The incidence of chronic GVHD was 71.7%. Disease-free survival at 5 years was 53.2% for patients with standard risk disease and 24.5% for patients with high-risk disease. Patients with chronic GVHD exhibited better disease-free survival than those without chronic GVHD (53.2 vs. 30.9%, P = 0.011). Twenty patients (36.4%) had a relapse of leukemia and 14 of them died of recurrent leukemia. This study indicates tacrolimus and methotrexate can lower the risk of severe acute GVHD after HLA-A, B, or DRB1 genotypically 1 locus mismatched UR-BMT.

Outcome of Non-T-Cell-Depleted HLA-Haploidentical Hematopoietic Stem Cell Transplantation from Family Donors in Children and Adolescents

Non-T-cell-depleted HLA-haploidentical hematopoietic stem cell transplantation (SCT) from family members has been reported, but its effectiveness and safety are not fully known. In this study, we examined the outcomes of 83 children and adolescents with nonmalignant (n = 11) or malignant (n = 72) disorders who underwent SCT mismatched at 2 or 3 HLA loci, either from the mother (n = 56), a noninherited maternal antigen (NIMA)-mismatched sibling (n = 14), or the father/a noninherited paternal antigen (NIPA)-mismatched sibling (n = 13). Engraftment was satisfactory. Severe (grade III-IV) acute graft-versushost disease (GVHD) was noted only in malignant disease, with an incidence of 21 of 64 evaluable patients. GVHD prophylaxis with a combination of tacrolimus and methotrexate was significantly associated with a lower risk of severe acute GVHD, compared with other types of prophylaxis (P = .04). Nine of 11 patients with nonmalignant disease and 29 of 72 patients with malignant disease were alive at a median follow-up of 26 months (range, 4-57 months). Outcomes were not significantly different among the 3 donor groups (mother versus NIMA-mismatched sibling versus father/NIPA-mismatched sibling) for the malignancy disorders. Our results indicate that non-T-cell-depleted HLA-haploidentical SCT may be feasible, with appropriate GVHD prophylaxis, for young recipients who lack immediate access to a conventional stem cell source.

Serum elastase and antithrombin-3 levels after umbilical cord blood transplantation or bone marrow transplantation

The severity of graft-versus-host disease (GVHD) was compared after cord blood transplantation (CBT) and bone marrow transplantation (BMT). The severity of GVHD was also analyzed in relation to serum elastase and antithrombin-3 (AT-3) levels. There was no significant difference in the average grade of acute GVHD between 49 BMT patients and 20 CBT patients (X2-test). However, there was a lower incidence of patients without acute GVHD (grade 0) or patients with severe acute GVHD (grade 3 or 4) in CBT compared with BMT group. Linear regression analysis found no significant correlation between the serum elastase level and the grade of acute GVHD, between the serum AT-3 level and the grade of acute GVHD, or between the serum levels of elastase and AT-3 before conditioning and after engraftment. The AT-3 level after engraftment was significantly higher in the CBT group than in the BMT group and it did not fail along with the elevation of elastase in the CBT group (p < 0.01 by the Mann–Whitney U-test vs. the BMT group). In conclusion, the lower risk of severe acute GVHD in the CBT group may have been related to the smaller decrease of AT-3 after transplantation.

MHC Haplotype Matching for Unrelated Hematopoietic Cell Transplantation

BackgroundCurrent criteria for the selection of unrelated donors for hematopoietic cell transplantation (HCT) include matching for the alleles of each human leukocyte antigen (HLA) locus within the major histocompatibility complex (MHC). Graft-versus-host disease (GVHD), however, remains a significant and potentially life-threatening complication even after HLA-identical unrelated HCT. The MHC harbors more than 400 genes, but the total number of transplantation antigens is unknown. Genes that influence transplantation outcome could be identified by using linkage disequilibrium (LD)-mapping approaches, if the extended MHC haplotypes of the unrelated donor and recipient could be defined.Methods and FindingsWe isolated DNA strands extending across 2 million base pairs of the MHC to determine the physical linkage of HLA-A, -B, and -DRB1 alleles in 246 HCT recipients and their HLA-A, -B, -C, -DRB1, -DQB1 allele-matched unrelated donors. MHC haplotype mismatching was associated with a statistically significantly increased risk of severe acute GVHD (odds ratio 4.51; 95% confidence interval [CI], 2.34–8.70, p < 0.0001) and with lower risk of disease recurrence (hazard ratio 0.45; 95% CI, 0.22–0.92, p = 0.03).ConclusionsThe MHC harbors genes that encode unidentified transplantation antigens. The three-locus HLA-A, -B, -DRB1 haplotype serves as a proxy for GVHD risk among HLA-identical transplant recipients. The phasing method provides an approach for mapping novel MHC-linked transplantation determinants and a means to decrease GVHD-related morbidity after HCT from unrelated donors.

The Effect of Killer Immunoglobulin-Like Receptor (KIR) Ligand Incompatibility on Outcome of Unrelated Donor Bone Marrow Transplantation (UDT).

KIR ligand incompatibility in the graft-versus-host (GvH) direction has been associated with a significant reduction in relapse, graft rejection and graft-versus-host disease (GvHD) in patients with high-risk acute myeloid leukemia (AML)undergoing full haplotype-mismatched, T-cell depleted transplants. The effect in UDT has been less consistent. This study investigates the effect of KIR ligand mismatching on the outcome of UDT in a large combined data set from the National Marrow Donor Program and the European Group for Blood and Marrow Transplantation, comparing the outcome of 1,816 KIR ligand matched and mismatched transplants for AML (n=501), chronic myelogenous leukemia (n=1024), and myelodysplasia (n=291). All cases had high-resolution HLA typing, and were matched for HLA-A, and -DRB1 alleles. Based on HLA typing for -B and -C alleles, cases were divided into one of 4 groups for comparison of outcome: KIR ligand incompatible in GvH direction (n=156), KIR ligand incompatible in host-versus-graft (HvG) direction (n=185), HLA mismatched for -B and/or -C, KIR ligand compatible (n=301), and fully HLA matched (n=1174). All received myeloablative preparative regimens, and ex-vivo T-cell depletion of the graft was performed in 18%, 22%, 16% and 15% of patients in the 4 groups, respectively. Overall, a beneficial effect of KIR ligand incompatibility in the GvH direction could not be demonstrated. KIR ligand incompatibility was associated with increased risk of grade III/IV acute GvHD and worse overall survival (OS). However, the effect varied according to whether or not ex-vivo T-cell depletion of the graft was performed (see Table). Our results suggest a detrimental effect of KIR ligand incompatibility in unmanipulated UDT, whereas this negative effect is lost with ex-vivo T-cell depletion. With ex-vivo T-cell depletion, KIR ligand incompatibility in the GvH direction may be associated with a reduced risk of severe acute GvHD and improved OS compared to HLA mismatched, KIR ligand matched transplants, with the outcome approaching that of fully HLA matched transplants. Therefore, full MHC class I matching remains the best option in UDT. KIR ligand mismatching in the GvH direction may be considered if only HLA-B and or -C incompatible donors are available and ex-vivo T-cell depletion is performed. This requires validation in prospective studies.GvH KIR ligand mismatchHvG KIR ligand mismatchNo KIR ligand mismatch, HLA mismatchHLA matchedP-valueT-cell depleted UDTTreatment mortality51% ± 17%64% ± 14%61% ± 13%47% ± 7%0.12Grade III/IV acute GvHD14% ± 13%25% ± 13%37% ± 13%17% ± 6%0.04Chronic GvHD at 3 years50% ± 21%39% ± 17%32% ± 15%53% ± 8%0.09Relapse18% ± 14%12% ± 9%22% ± 11%20% ± 6%0.49OS31% ± 17%27% ± 14%18% ± 11%38% ± 7%0.06T cell replete UDTTreatment mortality63% ± 8%63% ± 8%54% ± 6%44% ± 3%<0.0001Grade III/IV acute GvHD47% ± 9%45% ± 8%31% ± 6%28% ± 3%<0.0001Chronic GvHD at 3 years45% ± 10%67% ± 9%61% ± 7%63% ± 3%0.005Relapse22% ± 7%12% ± 5%15% ± 4%17% ± 2%0.09OS19% ± 7%28% ± 8%33% ± 6%43% ± 3%<0.0001

Contribution of T-Cell Reconstitution during the Early Phase after Cord Blood Transplantation to Favorable Clinical Outcomes.

The immaturity of T cells in cord blood is well known in functional assays and phenotypic analyses. During the first several months after cord blood transplantation (CBT), the T cell compartment is recovered by peripheral expansion from those mature and naïve T cells in cord blood grafts and plays an important role in acute graft-versus-host disease (GVHD) and graft-versus-leukemia reaction. Recently, we have reported that adult patients with hematological malignancies receiving CBT from HLA-partially-mismatched unrelated donors (n=68) had a lower risk of severe acute GVHD (> grade II, 7% versus 26%) and transplant-related mortality (9% versus 29% at 1 year) and a higher probability of disease-free survival (74% versus 44% at 2 years) than HLA-matched unrelated bone marrow transplant (BMT) recipients (n=45) in our multivariate analysis (Takahashi et al., Blood, in press). We speculated that the immune reconstitution process over a period of several months after CBT might have contributed to these promising clinical results. Using four-color analysis with CD4, CD8, CD45RA, and CD62L, more than 90% of cord blood CD4+ and CD8+ T cells in the grafts belonged to the naïve fraction. Cytokine expression in cord blood T cells was also suppressed to 0.1% in CD4+ and to 0.9% in CD8+ with positive interferon-γ by intracellular staining, which were significantly lower than those in adult T cells (16.2% in CD4+ and 37.8% in CD8+). Circulating T cell counts normalized after 3 months for CD8+ and 4 months for CD4+ in our CBT recipients, both of which were significantly faster than in previously published studies, which were 9 months for CD8+ and 12 months for CD4+. After T cell recovery, peripheral blood T cells moved from the naïve to the central memory fraction immediately, and then moved to the effector memory fraction. A naïve subset of CD4+ T cells remained (median: 38 cells/μl on day 90, n=12) during the first 3 months, which was significantly higher than in the BMT control (median: 9 cells/μl on day 90, n=5, p=0.015), but showed a low level of CD8+ T cells (median: 14 cells/μl on day 90, n=12), almost the same as in BMT recipients (median: 13 cells/μl on day 90, n=5). Intracellular interferon-γ-producing T cells were detected at 3.4% (0.1–34.2%) in CD4+ and 32.3% (1.1–86.9%) in CD8+ at 1 month post-CBT (n=16), both of which were comparable to post-BMT. To investigate whether these T cells with memory phenotype are functional, we analyzed antigen-specific T-cell recovery using cytomegalovirus (CMV) as a specific antigen. CMV-responsive CD4+ T cells were detected within the first 4 months in all recipients with positive CMV antigenemia (n=13), but CD8+ T cells were detected only in 5 out of 13 cases, probably because of pre-emptive Gancyclovir administration in most antigenemia-positive patients. To conclude, naïve cord blood T cells rapidly increased in number and adopted a memory phenotype showing cytokine-production and antigen-recognition capacity in the early phase after CBT. These data suggest that mature T lymphocytes in cord blood have unique properties and contribute to the favorable clinical outcome of CBT.

ABO compatibility and acute graft-versus-host disease following allogeneic bone marrow transplantation.

If ABO antigens/antibodies play any role in the pathogenesis of acute graft-versus-host disease (GVHD), one would expect the highest incidence of GVHD in recipients of minor ABO-mismatched grafts, followed by ABO-matched grafts, and the lowest incidence in major ABO-mismatched transplants. To test this hypothesis 174 patients receiving an HLA-identical allogeneic bone marrow transplant (BMT) for aplastic anemia (n = 32) or leukemia (n = 142) were analyzed for factors associated with acute GVHD. Variables analyzed included diagnosis, sex, age, blood group of donor and recipient, ABO compatibility, Rhesus compatibility, sex compatibility, number of bone marrow cells given at BMT, year of transplant, day of engraftment, and GVHD prophylaxis. We first carried out an exploratory contingency table analysis: minor ABO incompatibility was associated with a significantly higher risk of severe acute GVHD when compared with ABO-matched and major-ABO mismatched pairs (P = 0.003): 14/9, 57/67, and 5/22 patients developed, respectively, 0-I/II-IV acute GVHD in ABO major-mismatched, matched, and minor-mismatched pairs. Donors of group 0, (P = 0.06), older recipient's age (P = 0.08), fast engraftment (P = 0.03), and older donor's age (0.08) were also associated with a higher risk of GVHD. Recipient's ABO group, diagnosis, year of transplant, Rhesus group of donor or recipient, Rhesus compatibility, sex of donor or recipient, sex compatibility, and type of GVHD prophylaxis were not predictive of GVHD. A Cox multifactorial proportional hazards analysis confirmed that ABO matching was the single most significant factor associated with GVHD (P = 0.006). The cumulative incidence of GVHD grade II+ was 39%, 54%, and 82% for ABO major-mismatched, matched, and minor-mismatched pairs (P = 0.01). This study suggests that ABO antigens may play a role in the development of acute GVHD.