HLA-identical Hematopoietic Stem Cell Transplantation Research Articles

Outpatient ATG-free hematopoietic transplantation for aplastic anemia in limited-resource environments offers excellent results: Data from a single LATAM center

ObjectiveTo document the results of outpatient hematopoietic stem cell transplantation (HSCT) from the peripheral blood (PB) of sibling donors without anti-thymocyte globulin (ATG) in the conditioning regimen. Material and methodsPatients from a low-income population with severe AA who received a PB, unmanipulated sibling HLA-identical HSCT between 2000 and 2020 at a single institution were studied. Survival was the primary outcome. ResultsForty-one transplants were performed. Time between diagnosis and transplant was five months (1–104). Median age was 37 (range, 4–61) years; 25 (61 %) recipients were males and 32 (78 %) had treatment failure, 9 (22 %) have not received treatment. ATG was administered in 5 (12.2 %) cases; the graft source was PB in 38 (92.7 %) transplants. Twenty-six (63.4 %) transplants were carried out in the outpatient setting. Infections developed in 14 (34.1 %) patients. Primary graft failure (GF) occurred in 3 (7.3 %) patients. The 15-year OS was 81 %, EFS was 77.4 %. Patients with high pre-HSCT transfusion burden had lower OS (p = 0.035) and EFS (p = 0.026). Previous treatment failure and age were not associated with lower OS (p = 0.115, p = 0.069) or EFS (p = 0.088, p = 0.5, respectively). ConclusionsHLA-identical T-cell replete outpatient HSCT from the PB of sibling donors for AA patients using ATG-free conditioning offers excellent long-term survival.

Comparative Outcome of Reduced Intensity and Myeloablative Preparative Regimen in HLA Identical Sibling Allogeneic Hematopoietic Stem Cell Transplantation for Patients Older Than 50 Years of Age with Acute Myeloblastic Leukaemia: A Retrospective Survey from the Acute Leukemia Working Party (ALWP) of the European Group for Blood and Marrow Transplantation (EBMT).

Results of reduced intensity preparative regimen (RIC) hematopoietic stem cell transplantation (HSCT) in the HLA identical HSCT setting have not been compared to myeloablative HSCT (MA) in patients with AML over 50 years of age. With this aim, outcomes of 315 RIC were compared with 407 MA HSCT recipients from 182 transplant centers. The majority of RIC was fludarabine-based regimen associated to Busulfan (BU) (53%) or low dose TBI (24%). Multivariate analyses of outcomes were used adjusting for differences between both groups. The median follow-up was 13 months. Cytogenetics, FAB classification, WBC count at diagnosis and status of the disease at transplant were not statistically different between the two groups. However, RIC patients were older (median 57 years versus 54 years), transplanted more recently, and more frequently with peripheral blood allogeneic stem cells as compared to MA recipients. In multivariate analysis, Incidence of grade II-IV acute GvHD (aGvHD) was significantly lower after RIC: 22% compared to 31% after MA HSCT (p=0.003) but not Grade III-IV (8% versus 12%, respectively)(p=0.12). the risk of chronic GVHD was lower following RIC (RR=0.69; 95% CI,=0.51 to 0.94, p=0.02). Transplant-related mortality was significantly decreased(18% versus 32%) (p<10−4; RR=0.48, CI= 0.33 to 0.68), and relapse incidence was significantly higher (41% versus 24%) (p=0.0003; RR=1.78, CI=1.3 to 2.43) after RIC transplantation. Leukaemia-free survival (LFS) was not statistically different between the two groups. These results may set the grounds for prospective trials comparing RIC with other strategies of treatment in elderly AML.

Outcome of Age-Adapted Approach to HLA-Identical Related Hematopoietic Stem Cell Transplantation in Severe Sickle Cell Disease: Saudi Experience

▪Sickle cell disease (SCD) is one of the most common inherited disorders in Saudi Arabia with nearly 60,000 affected individuals (Alsultan et al. Ped. Transplant. 2016). Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment in SCD. A recent international survey showed excellent long-term survival of SCD patients after HLA-identical sibling HSCT; however, patients aged 16 years or older had higher risk of GVHD and mortality (Gluckman et al. Blood 2017). HLA-identical related HSCT in adult SCD patients using non-myeloablative (NMA) conditioning consisting of alemtuzumab, 300 cGy total body irradiation (TBI), and sirolimus was successful in establishing long term stable donor chimerism with minimal toxicity and GVHD (Hsieh et. al. JAMA 2014). In this study, we reviewed the outcome of SCD patients who underwent transplant at our institution using standard protocols (NMA regimen in patients ≥14 years and myeloablative regimen in < 14 years) to address whether age remains a risk factor that influences HSCT outcome in SCD.Children (<14 years) with severe SCD received myeloablative conditioning using one of two regimens: first regimen was cyclophosphamide (Cy) 200mg/kg, busulfan (Bu) 16mg/kg, and thymoglobulin (ATG) 10mg/kg and recently we use thiotepa 8mg/kg, Bu 16mg/kg, and fludarabine (Flu) 160mg/m2. Bu pharmacokinetics was performed to target AUC of 900-1350 µmol/L.min. GVHD prophylaxis included cyclosporine and methotrexate 10mg/m2 on day +1, +3, and +6. Bone marrow was the source of stem cells in all pediatric patients. Cyclosporine was continued during the first-year post HSCT and tapered slowly afterward based on donor chimerism. Adult patients (≥14 years) received hydroxyurea at maximum tolerated dose and hypertransfusion for 2-3 months with iron chelation if indicated prior to HSCT followed by NMA conditioning consisting of alemtuzumab (1mg/kg divided over 5 days on day -7 to -3) and TBI 300 cGy with testicular shielding in males on day -1. Sirolimus was used as GVHD prophylaxis starting day -2 and continued for at least one-year post HSCT with subsequent taper based on donor chimerism. Stem cells source was GCSF mobilized peripheral blood stem cells in all adult patients targeting cell dose of CD34 10X106/kg based on recipient weight. All SCD patients underwent exchange transfusion prior to HSCT to achieve HbS <30%. Hemoglobin was maintained between 9-11 g/dL and platelet count > 50,000/uL during HSCT. Supportive care included penicillin V, acyclovir, antifungal, and Pneumocystis jiroveci pneumonia prophylaxis. Levetiracetam was used as seizure prophylaxis. Strict monitoring of blood pressure and magnesium was performed. Graft failure and death from any cause were considered as events.A total of 51 patients with severe SCD were transplanted at our center, 17 children and 34 adults. Patient and transplant characteristics are summarized in Table. Indications for HSCT included recurrent severe pain crisis (n=33), stroke (n=14), avascular necrosis (n=2), sickle cell hepatopathy (n=1), and priapism (n=1). All patients engrafted successfully for both neutrophil and platelets. There was no acute or chronic GVHD among adult patients. Two pediatric patient had mild grade I acute GVHD in the skin that was controlled with topical treatment and none of pediatric patients had chronic GVHD. Three adult patients developed secondary graft failure on day 61, 170, and 225 post transplant with aplastic marrow in two patients despite full donor chimerism and autologous recovery in the third patient. Among the two patients who had aplastic anemia, one died secondary to sepsis and one underwent successful second transplant using cyclophosphamide, Flu, and ATG. Thirty-one adults have stable donor chimerism. Event free survival (EFS) at 2 years was 90% in adult patients and 100% in children (P=0.3). Overall survival (OS) at 2 years was 97% in adults and 100% in children (P=0.4). Median follow up duration was 416 days (range, 61-1256) in adults and 203 (range, 30-2505) days in children.We demonstrated that age-adapted approach in guiding the choice of conditioning regimen intensity in severe SCD is associated with excellent outcome and minimal risk of graft rejection, GVHD, and transplant-related mortality. This real world data is important to encourage patients and transplant physicians to consider this curative treatment. Longer follow up duration is needed to confirm our findings. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Long-term safety and survival outcomes after TK-expressing donor lymphocyte infusion (TK-DLI) in allogeneic hematopoietic stem cell transplantation (HSCT).

7007 Background: Suicide gene therapy (SGT) was firstly applied to allogeneic HSCT, addressing the need for modulation of graft vs host disease (GvHD) reactions while preserving graft vs leukemia (GvL) effect of alloreactive T cells. HSV-TK gene insertion in donor T-cells modulates alloreactivity by selectively destroying dividing alloreactive cells involved in GvHD. Methods: Long-term safety and survival was assessed in 128 pts entering worldwide 10 phase I-II trials that used TK-DLI to improve GvL, immune reconstitution (IR) and GvHD control. In all, 57 pts received TK DLI at our Institution: 23 to treat relapse after HLA-identical HSCT (Ciceri, 2007) and 34 to improve IR after haploidentical HSCT (Ciceri, Bonini, 2009). Results: SGT was feasible, safe and effective in promoting a dynamic and specific modulation of alloreactivity. TK-DLI clinical benefit, defined by chimerism, tumor response and/or IR, was achieved by 65 pts (51%). Grade 2 to 4 GvHD (n=28, 22%) was fully controlled by SGT. TK-DLI engrafted in 51 pts (90%) and, being detectable at low frequency up to 14 yrs, no SGT-related adverse events occurred. In HLA-identical setting (n=23; median follow-up, 15 yrs), 11 pts (48%) had disease response and 2 pts (9%) were alive in complete response (CR). In haploidentical setting (n=34; median follow-up, 7 yrs), 25 pts (73%) had IR and 9 pts (26%) were alive in CR. All pts were monitored according to guidelines on long-term survivors (Majhail, 2012). There were no major infections, while 3 pts had a second tumor. Immunity against TK-DLI was reported exclusively after HLA-identical allo-HSCT indicating that TK-DLI is not limited by SGT-specific immunity after haploidentical HSCT. Conclusions: Long-term follow-up confirms the high benefit to risk ratio of TK-DLI. A phase III trial is ongoing in haploidentical HSCT (NCT00914628). Clinical trial information: NCT00423124.

Do FY Antigens Act As Minor Histocompatibility Antigens in the Graft-Versus-Host Disease Paradigm After Human Leukocyte Antigen-Identical Sibling Hematopoietic Stem Cell Transplantation?

FY antigens are candidate minor histocompatibility antigens relevant to renal allograft rejection, but no data have been reported about their role in graft-versus-host disease (GVHD) incidence after human leukocyte antigen (HLA)-identical siblings hematopoietic stem cell transplantation (HSCT). The aim of this study was to examine the effect of donor/recipient disparity at FY antigens on the incidence of GVHD in Tunisian patients receiving an HLA-identical HSCT. This work enrolled 105 Tunisian pairs of recipients and their HLA-identical sibling donors of HSCs. FY genotyping was performed with the polymerase chain reaction-sequence-specific primer method and donor/recipient disparity for these antigens was analyzed at two levels: incompatibility and nonidentity. The case-control analyses showed no significant correlation between FY disparity and the incidence of either acute or chronic GVHD. Sample size calculation showed that 572 cases and 1716 controls would be necessary to be able to detect a significant association with 80% power and two-sided type I error level of 5% (α=0.05). The lack of association in the studied cohort may be explained by the low immunogenicity of FY antigens in HSCT context, compared with other antigens such as HA-1 and CD31.

Analysis of Risk Factors Influencing Outcomes After Unrelated Cord Blood Transplantation In Children with Juvenile Myelomonocytic Leukemia. An Eurocord, EBMT, EWOG-MDS, CIBMTR Study

AbstractAbstract 533Juvenile myelomonocytic leukemia (JMML) is a rare and lethal myeloproliferative disease of young childhood. Currently, allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment option. DFS at 5 years after HLA identical and unrelated HSCT was 55% (n=48) and 49% (n=52) in a largest series of patients published so far and mainly transplanted with bone marrow cells. Unrelated Cord Blood Transplantation (UCBT) is considered an alternative option for patients who lack an HLA-matched donor. We retrospectively analyzed 110 children, given a first single unmanipulated UCBT, from 1995 to 2010, and reported to Eurocord-EBMT and CIBMTR. Median age was 1 year (range 0.08–6.4) at diagnosis and 2 years (0.5-7.5) at transplantation, respectively. Median time interval between diagnosis and UCBT was 6 months (1-58); before transplantation, 88 patients were treated with low- or high-dose chemotherapy and splenectomy was performed in 24 children. Among 100 patients with available cytogenetic data, monosomy of chromosome 7 was the most frequent abnormality (24%). All but 8 patients received a myeloablative conditioning, Busulfan-Cyclophosphamide-Melphalan (BuCyMel) was used in 48 patients, total body irradiation (TBI) and Cyclophosphamide in 19 patients and combination of Busulfan-Cyclophosphamide with other drugs in 21 patients. Cyclosporin+steroid was the most common graft-versus-host disease (GvHD) prophylaxis (80%) and ATG was added in 86% of patients. Nineteen percent of units were HLA-identical (antigen level for HLA-A and B, allelic for DRB1), while 43% and 38% had 1 or 2–3 mismatches, respectively. Median TNC infused was 7.1×10e7/kg (1.7-27.6). Median follow-up was 44 months (3-169). At 60 days, cumulative incidence (CI) of neutrophil (PMN) recovery was 80±4%, with a median time to PMN recovery of 25 days. Grades II-IV acute GvHD developed in 45 patients, 100 days-CI of grade II-IV aGvHD was 40±5%. Among 90 patients at risk, 17 developed chronic GvHD and 4 years-CI was 16±4%. At 4 years CI of relapse was 37±5% (n=38); age older than 1 year at diagnosis was the only independent factor associated with increased risk of relapse (HR 2.3, p=0.038). Of note, among 58 patients with available data for level of fetal hemoglobin (HbF), a higher level of HbF (>35%) seemed to be associated with increased relapse incidence (57% versus 31% for remainders; p=0.05). At 4 years, DFS was 43±5%, in multivariate analysis independent factors associated with better DFS were: age younger than 1 year at diagnosis (53% vs 30%, HR 2.4, p=0.001), graft with 0 or 1 HLA mismatched cord blood unit (48% vs 34%, HR=2.1, p=0.006) and cytogenetic without monosomy 7 (48% vs 26%; HR=1.95, p=0.027). At 4 years, CI of transplant related mortality (TRM) was 20±4%; in multivariate analysis, cytogenetic with monosomy 7 (HR=2.7, p=0.036) and transplantation performed before 2003 (HR=3.7, p=0.015) were factors associated with increased TRM. In fact, CI of TRM was 14% after 2003 compared to 30% before 2003. Estimated overall survival (OS) at 4 years was 51±5%, and in multivariate analysis factors associated with decreased OS were: age older than 1 year at diagnosis (42% vs 60%; HR=2.03, p=0.032), and cytogenetic with monosomy 7, (30% vs 57%; HR=2.6, p=0.004). Fifty-one patients died after transplant, 53% for relapse and 47% for transplant related causes. In conclusion, UCBT may cure approximately 50% of patients with JMML who lack a matched related donor. Presence of monosomy 7 is associated with decreased DFS and increased TRM, independent of other factors. Other patient- (age at diagnosis) and transplantation-related factors (HLA and year of transplantation) were also associated with outcomes. Disease recurrence remains the major cause of treatment failure, and strategies to reduce the risk of relapse are warranted. Disclosures:Wagner:CORD:USE: Membership on an entity's Board of Directors or advisory committees; VidaCord: Membership on an entity's Board of Directors or advisory committees.

Relapse of leukemia with loss of mismatched HLA resulting from uniparental disomy after haploidentical hematopoietic stem cell transplantation

AbstractWe investigated human leukocyte antigen (HLA) expression on leukemic cells derived from patients at diagnosis and relapse after hematopoietic stem cell transplantation (HSCT) using flow cytometry with locus-specific antibodies. Two of 3 patients who relapsed after HLA-haploidentical HSCT demonstrated loss of HLA alleles in leukemic cells at relapse; on the other hand, no loss of HLA alleles was seen in 6 patients who relapsed after HLA-identical HSCT. Single-nucleotide polymorphism array analyses of sorted leukemic cells further revealed the copy number-neutral loss of heterozygosity, namely, acquired uniparental disomy on the short arm of chromosome 6, resulting in the total loss of the mismatched HLA haplotype. These results suggest that the escape from immunosurveillance by the loss of mismatched HLA alleles may be a crucial mechanism of relapse after HLA-haploidentical HSCT. Accordingly, the status of mismatched HLA on relapsed leukemic cells should be checked before donor lymphocyte infusion.

Immunomonitoring of graft‐versus‐host minor histocompatibility antigen correlates with graft‐versus‐host disease and absence of relapse after graft

After HLA-identical hematopoietic stem cell transplantation, minor histocompatibility (mH) antigen alloreactivity plays a dominant role in the development of graft-versus-host disease (GVHD) and graft versus leukemia (GVL). We have analyzed the mH alloreactivity (enzyme-linked immunospot [ELISpot] for interferon-gamma[IFN-gamma] assay) from 24 donor/recipient pairs over a period of 2 years of follow-up and correlated such alloreactivity with the development of GVHD or absence of relapse. Circulating specific T cells anti-mH with multimer HLA-peptides were also studied. We show by ELISpot IFN-gamma assay that alloreactivity during the first 3 months from donor versus recipient or donor versus mismatched identified mH antigens is associated with acute GVHD and GVL effect. In addition, we demonstrate that the donor-versus-recipient reactivity observed after the third month is highly associated with chronic GVHD and GVL (p = 0.0007). Finally, we show by multimer HLA-peptide assay that mH epitope-specific T cells present after 3 months are statistically related to the GVL effect. Our results provide a robust method to monitor mH antigen graft-versus-host reaction and suggest that current identified mH have predictive value on GVHD and GVL.

Allogeneic Stem Cell Transplantation Using Myeloablative and Reduced-Intensity Conditioning in Patients with Major Histocompatibility Complex Class II Deficiency

Major histocompatibility complex class II (MHC II) deficiency is a rare combined immunodeficiency disease. Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment. Between June 1994 and February 2007, 30 children with MHC II deficiency underwent a total of 33 HSCT procedures. Median age at HSCT was 27 months. The stem cell source was unmanipulated bone marrow from HLA-identical related donors in 26 patients, one HLA antigen-mismatched bone marrow in 3 patients, and unrelated umbilical cord blood in 1 patient. Conditioning was with one of 3 myeloablative regimens--regimen A (18 patients): busulfan (Bu), cyclophosphamide (Cy), and etoposide; regimen B (2 patients): Bu, Cy, and antithymocyte globulin (ATG); or regimen C (1 patient): CY and total body irradiation (TBI)--or with a reduced-intensity regimen (12 patients): fludarabine, melphalan, and ATG. The median CD34 cell dose was 8.3 x 10(6)/kg. Twenty patients experienced immune reconstitution and had sustained engraftment ranging from 9% to 100% for lymphoid lines and from 5% to 100% for myeloid lines that were significant to cure the disease. The overall disease-free survival rate was 66% and 76% after HLA-identical HSCT, with a median follow-up of 6.3 years, which is higher than previously reported. In HLA-identical transplant recipients, reliable donor stem cell engraftment and immune reconstitution were achieved through myeloablative or reduced-intensity conditioning. Further studies and long-term follow-up are needed to determine the appropriate conditioning regimen.

The Role of Missing Killer Cell Immunoglobulin-Like Receptor Ligands in T Cell Replete Peripheral Blood Stem Cell Transplantation from HLA-Identical Siblings

The contribution of natural killer (NK) cells to graft-versus-malignancy (GVM) effects following hematopoietic stem cell transplantation (HSCT) remains uncertain, particularly in the HLA-identical setting. A model considering missing HLA ligands to the donor's inhibitory killer cell immunoglobulin-like receptor (KIR), termed the missing KIR ligand model, has been established in T cell depleted bone marrow transplantation (BMT), but lacks validity in other cohorts with different treatment characteristics. We hypothesized that the impact of missing KIR ligands on relapse-free survival (RFS) and overall survival (OS) in T cell replete peripheral blood SCT (PBSCT) differs from that in the T cell depleted BMT setting, and retrospectively evaluated 100 consecutive, HLA-identical sibling transplantations for hematologic malignancies. In addition to KIR ligand status, we considered the donors' activating KIRs and grafted NK, T, and CD34(+) cell doses. Our findings demonstrate noninferiority for OS (P = .005) and RFS (P = .002) for the heterozygous HLA-C group KIR ligand status (C1/2; n = 47) compared with patients missing either C1 or C2 (n = 53). Similarly, OS (P = .031) and RFS (P = .034) of Bw4-positive patients was noninferior to that of patients missing a Bw4 ligand to KIR3DL1. By multivariate analysis, C1/2 heterozygous patients had a favorable risk ratio (RR) for relapse (RR = 0.28; P = .003), RFS (RR = 0.56; P = .046), and acute graft-versus-host disease grade II-IV (RR = 0.36; P = .05). Following reduced-intensity conditioning (RIC), but not standard-intensity conditioning, myeloablative (MA) transplantation, a grafted NK cell dose above the median (3.4 x 10(7)/kg) was associated with a lower risk of relapse (RR = 0.57; P = .003) and improved survival (RR = 0.78; P = .03). Overall, our findings support a role for NK alloreactivity in HLA-identical HSCT, but argue against a favorable impact of missing KIR ligands in the given setting. We conclude that the mechanism favoring the missing KIR ligand constellation in T cell depleted BMT may not operate in T cell replete PBSCT. The reasons for this differential effect remain unresolved.

Role of Antithymocyte Globulin and Granulocyte-Colony Stimulating Factor-Mobilized Bone Marrow in Allogeneic Transplantation for Patients with Hematologic Malignancies

The main obstacle for allogeneic transplantation is delayed hematologic reconstitution and serious graft-versus-host disease (GVHD). The results of 128 patients with hematologic malignancies undergoing HLA -identical (n = 52) or HLA-haploidentical/mismatched (n = 76) hematopoietic stem cell transplantation (HSCT) performed during the same time period were compared. Patients with HLA-identical HSCT received unmanipulated granulocyte-colony stimulating factor -mobilized peripheral blood stem cells (G-PBSCs). Forty-six patients with HLA-haploidentical related HSCT received antithymocyte globulin (ATG) in conditioning regimens followed by the transplantation of the combination of unmanipulated G-PBSCs and granulocyte-colony stimulating factor -mobilized bone marrow (G-BM) and 30 patients with HLA-mismatched unrelated HSCT received ATG in conditioning regimens followed by the transplantation of unmanipulated G-PBSCs. All patients got successful hematopoietic engraftment. The cumulative incidences of grades I to II acute GVHD (aGVHD) on day 100 in the identical, haploidentical related and mismatched unrelated cohorts were 21.2%, 43.5%, and 53.3%, respectively. The cumulative incidences of chronic GVHD (cGVHD) in the identical, mismatched unrelated, and haploidentical related cohorts were 34.6%, 33.3%, and 10.9%, respectively. The 2-year relapse and treatment-related mortality (TRM) rates were 19.2%, 23.9%, 23.3%, and 9.6%, 8.7%, 10% for patients who underwent identical, HLA-haploidentical related, and mismatched unrelated transplantation, respectively. The 2-year probabilities of leukemia-free survival and overall survival were 72.2%, 70.6%, 68.1%, and 76.5%, 77.8%, 70.0% after identical, haploidentical related and mismatched unrelated transplantations, respectively. Multivariate analyses showed that only advanced disease stage and a diagnosis of disease had increased risk of relapse, treatment failure, and overall mortality. In conclusion, it is a feasible approach with acceptable outcomes for patients undergoing HLA-haploidentical related HSCT by the combination of G-PBSCs and G-BM with conditioning regimens including ATG.

Mesenchymal Stem Cells Derived from Different Donors as Salvage Therapy for Resistant Severe Acute Graft-Versus-Host Disease

Severe Acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation(allo-HSCT), especially severe intestinal aGVHD, is associated with a high morbidity and mortality rate and is a major threat to a successful outcome. Currently, corticosteroids are still the first-line treatment for established aGVHD with a response rate of 30–50%; however, patients who fail on standard therapy have poor outcome, and therapeutic options avail able for them are limited. Mesenchymal stem cells (MSCs) are multipotent cells able to differentiate into different tissues and also have immunomodulatory effects, inhibit T-cell proliferation in mixed lymphocyte cultures, prolong skin allograft survival. Recently, Le Blanc and Fan B et al. respec tively reported their experience of using vitro expanded MSCs to treat severe, resistant aGVHD of the gut and liver, and the results showed rapid improvement after infusion of MSC. Thus, MSC may be used for the treatment of severe acute GVHD. The purpose of our study was to evaluate further the efficacy of ex vivo expanded MSC as the salvage therapy for severe refractory acute GVHD. Between February, 2006, and July, 2007, four patients with gastrointestinal grade III to IV acute GVHD after sibling HLA-identical hematopoietic stem cell transplantation, who didn't respond to steroid therapy (≥2mg per kg per day) for more than seven days, or with progression at least within 72 hours were treated with MSC. The study was approved by the Ethics Committee at Guangdong Provincial People's Hospital. All patients and the MSC donors gave them written informed consent. Eleven infusions of MSCs were given Fone patient had one infusion, others had two or more infusions. All of them, the first-infusion MSCs were derived from their HLA-identical sibling donors, and the second or more MSCs were derived from different HLA-mismatched unrelated donors. The median dose given to patients was 0.5×106 cells per kg(range: 0.3 to 0.8×106 cells per kg). Median time from tansplantation of haemopoietic stem cells to infusion of MSCs was 58 days (range 28–63days). No patients had acute side-effects either during or after infusion. Total response rate was 100%. Two patients achieved complete response and the others achieved partial response. Four patients with gut aGVHD, two of them achieved complete response after the first dose infusion, and the other two achieved partial response and good partial response after the second and the third infusion, respectively. Otherwise, two of four patients with liver aGVHD, achieved partial response and complete response after the second and the third infusion. The median time from first infusion of MSCs to primary response time and fully response time was 3 days and 23 days(range: 2 to 5 days; 10 to 72 days) after MSC transfusion, respectively. Two patients had died of multiple cerebral infarction and the other one died of multiorgan failure. Just case 2 was alive and developed gut chronic GVHD. At last follow-up (July 31, 2008), the patient was in stable state and his immunosuppressive therapy is being tapped. In conclusion, our preliminary results support the hypothesis that MSC derived from either bone marrow or umbilical cord blood, HLA-identical or HLA-mismatched, single donor's or multiple donors' MSCs can be used safely and has encouraging efficacy in the treatment of patients with severe acute GVHD who was refractory to conventional immunosuppressive threapy, although our result may have been influenced by the small number of patients studies and the short observation period, however, in view of the dismal outcome in patients with grades III–IV acute GVHD, MSC seems promising.

Immunological Evaluation after Haematopoietic Stem Cell Transplantation for B–Thalassemia Major

Background: Haematopoietic stem cell transplantation (HSCT) remains the only curative option for patients with thalassemia. After HSCT is particularly important to recover a complete immune reconstitution for prevention of opportunistic infections.Methods: The immunological phenotype of peripheral blood mononuclear cells in 110 consecutively subjects after HLA identical HSCT performed for b thalassemia were studied. CD3+CD4+, CD3+CD8+, CD3−CD19+, CD3−CD16+CD56+ were evaluated by Flow Cytometry at 6 and 12 months after HSCT in 70 patients followed. In a part of patients CD4 naïve T cells was also evaluated at 12 months after HSCT.Results: at 6 months after HSCT we observed reduction of the mean of CD4 T cell percentage in patients respect normal value: in mean 17, 5 % ± 9 vs 45 % ± 10 respectively. After 1 year the rate of CD4+ T-cell population progressively increase: 24 ± 9 at 12 months vs 17, 5 % ± 9 at 6 months, but the mean of CD4+ T-cell count was persistently lower than in controls. The mean of CD8 T cell is stable during the follow up and the CD4/C8 ratio decreased. The mean of the CD19 increase during the follow up (4, 5 % at 6 months vs 17% at 12 months). At 1 year after HSCT the percentage of NK (CD3−CD16+CD56+) was normalized. At 1 year after HSCT reduction of naïve CD4 T cell we observed.Discussion. At 1 year after HSCT the immunological reconstitution is not still complete. The time and the extent of immune reconstitution depend on several factors. It is very important to continue the immune surveillance after HSTC and to evaluate other immunological parameters (i.e. thymic output) for to prevent infectious complications and elaborate an appropriate therapeutic strategy.

Association of drug metabolism gene polymorphisms with toxicities, graft-versus-host disease and survival after HLA-identical sibling hematopoietic stem cell transplantation for patients with leukemia

Individual differences in drug efficacy or toxicity can be influenced by genetic factors. We investigated whether polymorphisms of pharmacogenes that interfere with metabolism of drugs used in conditioning regimen and graft-versus-host disease (GvHD) prophylaxis could be associated with outcomes after HLA-identical hematopoietic stem cell transplantation (HSCT). Pharmacogenes and their polymorphisms were studied in 107 donors and patients with leukemia receiving HSCT. Candidate genes were: P450 cytochrome family (CYP2B6), glutathione-S-transferase family (GST), multidrug-resistance gene, methylenetetrahydrofolate reductase (MTHFR) and vitamin D receptor (VDR). The end points studied were oral mucositis (OM), hemorrhagic cystitis (HC), toxicity and venoocclusive disease of the liver (VOD), GvHD, transplantation-related mortality (TRM) and survival. Multivariate analyses, using death as a competing event, were performed adjusting for clinical factors. Among other clinical and genetic factors, polymorphisms of CYP2B6 genes that interfere with cyclophosphamide metabolism were associated with OM (recipient CYP2B6(*)4; P=0.0067), HC (recipient CYP2B6(*)2; P=0.03) and VOD (donor CYP2B6(*)6; P=0.03). Recipient MTHFR polymorphisms (C677T) were associated with acute GvHD (P=0.03), and recipient VDR TaqI with TRM and overall survival (P=0.006 and P=0.04, respectively).Genetic factors that interfere with drug metabolisms are associated with treatment-related toxicities, GvHD and survival after HLA-identical HSCT in patients with leukemia and should be investigated prospectively.

HLA-identical haematopoietic stem cell transplantation for acute leukaemia in children: less relapse with higher biologically effective dose of TBI

To examine relapse, survival and transplant-related complications in relationship to disease- and pre-treatment-related characteristics, we evaluated 132 children, who consecutively received an allogeneic HLA-identical SCT for acute leukaemia in our centre: ALL in first remission (n=24), ALL in second remission (n=53) and AML in first remission (n=55). The source of the stem cells was bone marrow in all but three cases. Most patients (89%) were pre-treated with cyclophosphamide and an age-related dose of TBI. Initially, GVHD prophylaxis consisted of long-course MTX only (n=24), later short-course MTX and CsA (n=102) was given. All patients were nursed in strictly protective isolation and received total gut decontamination to suppress their potentially pathogenic enteric microflora. The 5-year probability of overall survival was 63, 53 and 74% for ALL1, ALL2 and AML1, respectively (median follow-up: 10.6 years). The overall transplant-related mortality was 6%. The incidence of acute GVHD was 17%; 6% was grades II-IV. A higher total biologically effective TBI dose (BED) resulted in a decreased relapse frequency (P=0.034) and increased overall survival. AML patients with acute GVHD got no relapse (P=0.02); this was not the case in ALL patients. Fractionated TBI regimens with higher BED should be evaluated in prospective studies.

Delayed Onset GVHD Following Reduced Intensity Conditioning HSCT Is Associated with Persisting Host DC and Late Emergence of Activated Donor DC.

Allogeneic haematopoietic stem cell transplantation (HSCT) has relied on myeloablative conditioning (MAC) to ablate malignancy and control graft rejection. Conditioning is vital for HSC engraftment, however it up-regulates inflammatory cytokine and endotoxin levels, activates dendritic cells (DC) and initiates GVHD. Non-myeloablative, but immunosuppressive, reduced intensity conditioning (RIC) is increasingly used to combat treatment related mortality (TRM) associated with MAC. RIC reduces TRM and delays GVHD onset, but overall GVHD incidence is unchanged. We hypothesise that this is due to persistence of host DC.No clinically relevant in vivo murine models of RIC allogeneic HSCT have been reported to date, preventing studies of the mechanisms of RIC-associated delayed-onset GVHD. We developed two murine models of pre-transplant conditioning, which result in GVHD after infusion of donor cells [either MHC mismatched (UBI-GFP/BL6→BALB/c) or MHC-matched minor antigen mismatch (miHA; UBI-GFP/BL6→BALB.B), the latter mimicking allogeneic HLA-identical sibling HSCT]. These models combine clinical doses of cytotoxics (cyclophosphamide and fludarabine) with radiation, enabling us to monitor effects of these regimens on DC subsets and activation daily during conditioning and thereafter. GVHD onset is significantly delayed after RIC compared to MAC in HSCT recipients in MHC mismatched (MAC d+6 vs. RIC d+18–35; p<0.001) and miHA mismatched (MAC d+18–35 vs. RIC d+44–90; p<0.001) HSCT models (Fig 1). In HSCT experiments mice were sacrificed at defined time points post-HSCT and also when severe GVHD required sacrifice. In MHC mismatched RIC HSCT recipients, mice with severe GVHD had higher levels of donor engraftment in BM and spleen than those treated with MAC (Fig 2A). Timed sacrifice data showed persistence of activated (CD11c+MHCII+) host DC in BM of RIC treated mice until D+21, but this was tempered by an increase in activated donor DC (Fig 2B). This was in direct contrast to MAC treated mice, which maintained low levels of activated host DC (Fig 2B). In addition, activated DC present in BM of RIC HSCT mice at death due to GVHD are primarily of donor origin as compared with MAC HSCT mice (Fig 2C). Delayed emergence of activated donor DC in RIC treated mice preceded delayed onset GVHD in this model.These findings suggest that the major factors contributing to delayed-onset GVHD post-HSCT in RIC recipients are persistence of host DC and delayed emergence of activated donor DC. Delineating the effect of MAC and RIC regimens on DC provides a rationale to target activated DC as GVHD therapy. [Display omitted] [Display omitted]

Activating KIR genes are associated with CMV reactivation and survival after non-T-cell depleted HLA-identical sibling bone marrow transplantation for malignant disorders

Combinations of HLA and killer immunoglobulin-like receptors (KIR) may affect outcome in T-cell depleted haematopoietic stem cell transplantation (HSCT). The KIR gene family includes inhibitory (KIR2DL and 3DL) and activating receptors (KIR2DS). Ligands are HLA-C (KIR2D) and HLA-Bw4 (KIR3DL1) for inhibitory KIR and are still unknown for activating KIR. The impact of activating KIR genotypes from donor and recipient is poorly documented in HSCT outcome. Here, HLA and KIR genotypes were determined in 131 pairs from non-T-cell depleted HLA-identical sibling HSCT. No effect of 'missing KIR ligand' was detected on acute graft-versus-host disease (GVHD), relapse, survival or infections even in myeloid malignancies. However, additional activating KIR genes in the donor compared to the recipient's genotype or an identity between donor and recipient activating KIR genotypes was associated with a lower transplant-related mortality (TRM) (P=0.005) and in a multivariate analysis with a better survival (P=0.02, HR=0.28; P=0.013, HR=0.29) and a lower incidence of cytomegalovirus (CMV) reactivation (P=0.009, HR=0.36). These data highlight the impact of donor-activating KIR genes on TRM, overall survival and CMV reactivation in HLA-identical sibling HSCT.

Human leucocyte antigen‐identical haematopoietic stem cell transplantation in major histocompatiblity complex class II immunodeficiency: reduced survival correlates with an increased incidence of acute graft‐versus‐host disease and pre‐existing viral infections

Major histocompatibility complex class II deficiency, a rare autosomal recessive primary immunodeficiency, is caused by the defective expression of human leucocyte antigen (HLA) class II molecules due to mutated trans-acting elements of any one of four regulatory genes (CIITA, RFXANK, RFX5, RFXAP). The impaired CD4 T-cell differentiation and antigen presentation in the periphery results in a severe defect of cellular and humoral response consistent with severe recurrent infections, leading to a poor prognosis. Currently, allogeneic haematopoietic stem cell transplantation (HSCT) is the only curative approach, but the overall cure rate is lower than in other immunodeficiencies. We report a single centre experience of 17 HSCTs with 15 HLA-identical donors between 1981 and 2004. Eight patients survived, while the occurrence of acute graft-versus-host disease (GVHD) was 50%. This study aimed to identify potential risk factors for GVHD and outcome within pre-HSCT complications related to the immunodeficiency. Five of seven patients with pre-existing viral infections developed acute GVHD > or = grade II, of whom four died. Two of seven patients without detectable pre-existing viral infection developed GVHD > or = grade II, and one died. The difference was significant (P < 0.05). A plausible link with other factors potentially associated with the development of GVHD could not be found. We suggest that the reduced survival after HLA-identical HSCT may be caused by the high incidence of pre-existing viral infections and associated with the onset of severe acute GVHD.

HLA Identical Hematopoietic Stem Cell Transplantation for Acute Leukemia in Children - A Single Center Experience.

Between 1980 and 2002, 132 children and adolescents (median age 8.5 years, range 1.1 to 17.3) got an allogeneic HLA-identical hematopoietic stem cell transplantation (SCT) from a sibling donor for acute leukemia. The patients suffered from ALL in 1st remission (n=24), ALL in 2nd remission (n=53) and AML in 1st remission (n=55). The mean follow-up time after SCT was 11.5 years (range 1.3 to 23.3 years). The source of the stem cells was bone marrow in all but 3 cases of cord blood-derived stem cells. The number of nucleated marrow cells in the graft varied between 0.5 and 6.8x108/kg (median 2.75x108/kg). Most patients, 118 of 132, were pre-treated with a total body irradiation (TBI) and cyclophosphamide-based regimen. TBI doses were 1x 7 Gy for children of 3 and 4 years, 1x 7.5 Gy for >4 and <10 years, and 1x 8 Gy (before 1990) and 2x 6 Gy on two consecutive days (after 1990) for children older than 10 years. Initially, graft-versus-host disease (GvHD) prophylaxis consisted of long-course methotrexate (MTX) only (n=24), later a short-course MTX-Cyclosporine A prophylaxis was given (n=102). All patients were nursed in strict protective isolation, using positive-pressure laminar-air flow cubicles or rooms, and got total gut decontamination with non-absorbable antimicrobials. Engraftment, transplant-related complications, relapse of the disease and survival were evaluated retrospectively in relation to disease- and transplant-related characteristics. None of the patients failed to engraft. The mean 5-year probability of overall survival was 63%, 53% and 74% for ALL1, ALL2 and AML1 patients, respectively. Transplant-related mortality was 6%. The incidence of acute GvHD in evaluable cases was 17% (21/124), of whom 7 (6%) got grade II to IV. Chronic GvHD occurred in 10 patients out of 125 evaluable patients (8%). The mean 5-year probability of relapse was 35%, 49% and 26% for ALL1, ALL2, and AML1 patients, respectively. Most relapses (70%) occurred within the first year post-SCT. The patient age and dose of TBI were significantly related with post-transplant relapse (p=0.007). Overall survival was significantly higher in children that received a higher dose of TBI (see figure). Overall, acute GvHD was not significantly associated with relapse, but none of the AML patients (n=9) with acute GvHD got a relapse (likelihood ratio test, p=0.02), which was not the case for ALL first or second remission patients. This retrospective single-center study on HLA-identical SCT for acute leukemia in 132 consecutively enrolled children confirms the beneficial role of slight to moderate acute GvHD in the suppression of relapse of AML, and draws attention to the potential antileukemia effect of a high (fractionated) dose of TBI in the conditioning. [Display omitted]

A defined donor activating natural killer cell receptor genotype protects against leukemic relapse after related HLA-identical hematopoietic stem cell transplantation

Killer cell immunoglobulin-like receptors (KIRs) recognize different groups of Human Leukocyte Antigen (HLA) class I alleles and are expressed by natural killer (NK) cells and some T lymphocytes. NK cell cytotoxicity is triggered by failure to recognize the appropriate HLA class I ligand on target cells. Recently, it has been shown that HLA class I ligand incompatibility in the graft-versus-host (GvH) direction is associated with a better outcome in haploidentical hematopoietic stem cell transplantation (HSCT). Since KIR genotypes are very diverse in the population, we explored whether or not the donor KIR genotype could affect the graft-versus-leukemia (GvL) effect in the related HLA-identical HSCT setting. We determined the KIR and HLA genotypes of 65 HLA-identical patient-donor siblings. We found that the presence of two activating KIRs, 2DS1 and 2DS2, in the donor was significantly associated with a decreased leukemic relapse rate (P=0.03; OR=0.18; 95% CI: 0.037-0.88). Moreover, the probability of relapse at 5 years was significantly lower for patients who received a graft from a donor with the 2DS1(+)2DS2(+) genotype than for those who received a transplant from other donors (17 vs 63%, respectively; P=0.018). In conclusion, this study suggests that a joint effect of these two selected activating KIRs in the donor might confer some protection against leukemic relapse.