Outcomes and Long-Term Survival of Adolescent and Young Adult Patients Admitted to the Intensive Care Unit Following Allogeneic Hematopoietic Stem Cell Transplantation: A Single-Center Experience of 152 Patients.

BACKGROUND AND OBJECTIVES: Prognostic factors reliably predicting outcomes for critically ill adolescent and young adult (AYA) patients undergoing allogeneic hematopoietic cell transplantation (allo-HSCT) are lacking. We assessed transplant and intensive care unit (ICU)-related factors impacting patient outcomes. PATIENTS AND METHODS: AYA patients who underwent allo-HSCT and required ICU admission at a Tertiary care Centre, during the period of 2003-2013, were included in this retrospective review. This was a non-interventional study. Only outcomes after the first allo-HSCT and index ICU admissions were analyzed. Disease-, transplant-, and ICU-related variables were analyzed to identify risk factors predictive of survival. RESULTS: Overall, 152 patients were included (males, 60.5%); median age at transplantation was 24 years (interquartile range [IQR] 18-32.5); median age at admission to the ICU was 25.8 years (IQR 19-34). Eighty-four percent underwent transplantation for a hematological malignancy; 129 (85%) received myeloablative conditioning. Seventy-one percent of ICU admissions occurred within the first year after allo-HSCT. ICU admission was primarily due to respiratory failure (47.3%) and sepsis (43.4%). One hundred and three patients (68%) died within 28 days of ICU admission. The 1- and 5-year overall survival rates were 19% and 17%, respectively. Main causes for ICU-related death were refractory septic shock with multiorgan failure (n = 49, 32%) and acute respiratory distress syndrome (ARDS) (n = 39, 26%). Univariate analysis showed that ICU mortality was associated with an Acute Physiology and Chronic Health Evaluation (APACHE) II score >20, a sequential organ failure assessment (SOFA score) > 12, a high lactate level, anemia, thrombocytopenia, leukopenia, hyperbilirubinemia, a high international normalized ratio (INR) and acute graft-versus-host disease (GVHD). Multivariate analysis identified thrombocytopenia, high INR, and acute GVHD as independent predictors of mortality. CONCLUSIONS: In AYA allo-HSCT patients admitted to the ICU, mortality remains high. Higher SOFA and APACHE scores, the need for organ support, thrombocytopenia, coagulopathy, and acute GVHD predict poor outcomes.

Myeloablative Haploidentical Donor Hematopoietic Transplantation Using Post-Transplantation Cyclophosphamide and Antithymocyte Globulin.

Haploidentical donor (haplo-) hematopoietic stem cell transplantation (HSCT) with post-transplantation cyclophosphamide (PTCy) is now performed on a large scale worldwide. Our patient outcomes did not completely reflect the results published by other groups. We herein present the results of 60 patients with hematologic malignancies treated homogeneously on a modified version of the standard protocol by adding ATG as an additional graft-versus-host disease (GVHD) prophylaxis measure. This was a retrospective analysis of 60 haplo-HSCT recipients using a myeloablative conditioning regimen with antithymocyte globulin and PTCy for GVHD prophylaxis. At 5 years, overall survival was 59.2%, relapse-free survival (RFS) was 48.6%, and chronic GVHD (cGVHD) and relapse-free survival was 40%. The median time to neutrophil and platelet engraftment was 16 days and 28.5 days, respectively. The rates of grade II-IV acute GVHD and extensive cGVHD were 46.7% and 23.3%, respectively. The cumulative incidence of relapse was 30%, nonrelapse mortality was 21.6%, and transplantation-related mortality was 11%. Higher Disease Risk Index and 50% HLA match were associated with lower RFS. Female donor to male recipient and older donor age were associated with an elevated risk of cGVHD. The use of PTCy might not yield the same results in different populations. Many remaining questions need to be addressed in randomized trials, including optimal graft source and donor, date of calcineurin inhibitor initiation, personalized or targeted dose of PTCy, immune reconstitution, and others.

Incidence and risk factors for secondary graft failure in uniformly treated patients with severe aplastic anemia receiving fludarabine and cyclophosphamide for conditioning and matched sibling bone marrow graft as stem cell source.

BACKGROUND AIMS: Graft failure after allogeneic transplant for aplastic anemia is problematic. The risk of graft failure depends on multiple variables, including the preparative regimen, donor type, stem cell dose and source among other variables. METHODS: We performed a retrospective analysis of patients with aplastic anemia who underwent matched-sibling allogeneic transplant at a single center. RESULTS: We identified 82 patients who fit the inclusion criteria. One had primary graft failure and was excluded from this analysis. The recipient median age was 22 years. The donor median age was 23 years. The median time from diagnosis to transplant was 1.6 months. The median number of red cell transfusions before transplant was nine. The median number of platelet transfusions before transplant was 18. Thirteen patients developed secondary graft failure, with a cumulative incidence at 5 years of 16% and median time to develop secondary graft failure of 129 days. All patients engrafted with a median time for neutrophil engraftment of 19 days and a median time for platelet engraftment of 22 days. The survival of patients with or without secondary graft failure was not different. Major or bidirectional ABO incompatibility and older recipient age were statistically significantly associated with greater risk of secondary graft failure. CONCLUSIONS: Secondary graft failure is a significant complication after allogeneic transplant for SAA. Identification of recipients at risk and mitigating the potential risks of this complication is warranted.

Improved survival of adolescents and young adults patients with T-cell acute lymphoblastic leukemia.

Aim: The outcome of T-cell acute lymphoblastic leukemia (T-ALL) has improved with the use of pediatric-inspired protocols in the adolescents and young adults (AYA) population. There is limited literature regarding the outcome of T-ALL/lymphoblastic lymphoma (LBL) AYA patients treated with pediatric protocols. Methods: A total of 35 T-ALL/LBL-AYA patients ages between 14 and 55 years were treated with AYA-15 protocol. Results: At a median follow-up of 5 years the overall survival, disease-free survival and event-free survival are 71%, 62% and 49.6% respectively. Toxicities were within the expected range. Conclusion: Our single-center experience real-world data in treating T-ALL/LBL-AYA patients with pediatric-inspired protocol demonstrates encouraging results of high survival rate and excellent tolerability for patients aged 18-55 years.

"Incidence and significance of donor-specific antibodies in haploidentical stem cell transplantation".

PGF is a devastating complication after allogeneic transplant. We retrospectively analyzed our haploidentical transplant registry to report the incidence and impact of DSA and anti-HLA on engraftment. 107 patients were identified. Median recipient-age of 22, median donor-age of 31. Sixty-two patients had AML (58%), 29 had ALL (27%), 16 (15%) had other malignancies. Sixty-one recipients (57%) had positive anti-HLA, 56 of them had the DSA results available, of these 17 patients had DSAs (15% of the total number of patients, or 28% of patients who have anti-HLA antibodies). The median cumulative MFI was 2062. Sixty-three percent of the DSA were against class-II HLA antigens. The OS, CIR, aGvHD, and cGvHD did not differ between patients with and without anti-HLA antibodies, nor between patients with and without DSA. The gender of the recipient and donor, as well as the gender mismatch between recipient and donor, were statistically associated with the incidence of anti-HLA antibodies. Three patients only developed GF (2.8%), one was primary (0.9%) and the other two secondary GF (1.9%). None of the GF cases was in patients with anti-HLA antibodies or DSA. The presence of anti-HLA or DSAs did not affect the outcomes including the incidence of PGF.

Prevalence of the BCR/ABL fusion gene and T cell stimulation capacity of dendritic cells in chronic myelogenous leukemia.

Dendritic cell (DC) vaccines are promising for immunotherapy, and their production using CD34+ hematopoietic stem cells (HPSCs) from patients with chronic myelogenous leukemia (CML) and healthy donors is well established. However, the generation of CD1a+CD14- DCs and their functional properties in patients with CML remain elusive. Here, we aimed to study the biology of DCs generated from CD34-/low HPSCs and evaluate the status of their BCR/ABL translocation, ability to stimulate T cells, and capacity of endocytosis compared to DCs derived from CD34+ HPSCs from both patients with CML and healthy donors. CD1a+CD14- DCs were generated from CD34-/low HPSCs and evaluated morphologically and functionally. CD34+ cells are frequently selected for transplantation and the entire CD34-/low HPSC fraction is wasted. Here, we anticipated the CD34- HPSC subset to constitute an invaluable source for acquiring DCs for immunotherapy. CD34+ and CD34- HPSCs were sorted from the bone marrow samples of CML patients and healthy donors and differentiated ex vivo in a similar way. DCs from CD34-Lin- and CD34+Lin- HPSCs expressed comparable surface markers (CD80, CD83, CD86, HLA-DR, CD40, and CD54). Functional analysis revealed that DCs acquired from both subsets retained a potent allogeneic T cell stimulatory capacity and an efficient phagocytic ability and showed a similar BCR/ABL translocation status. In conclusion, DCs were successfully differentiated from the CD34-Lin- cell subset and showed potent functional capacities, indicating their potential for application in immunotherapy and basic research.

Allogeneic transplant compared to pediatric-inspired therapy for Philadelphia chromosome-negative adolescent and adult ALL in first complete remission.

BACKGROUND: Pediatric-inspired non-transplant regimens for adolescent and adult ALL patients are becoming standard in many institutions. We aimed to compare a cohort of patients receiving a pediatric-inspired protocol to a cohort of patients treated with adult type ALL therapy followed by allografting after achieving CR1. METHOD: Eighty-five adolescent and adult ALL patients treated with CALGB 19802 protocol who received MSD transplant in CR1 were retrospectively compared to a matched cohort of 72 adolescent and adult ALL patients treated with a modified version of Children's Cancer Group (CCG) 1900 protocol. RESULTS: The five years OS in the allo-HCT cohort was 63.1% compared to 80.2% in the pediatric-inspired chemotherapy arm (P = 0.03). The five years EFS in the allo-HCT arm was 58.8% compared to 61.6% in the pediatric-inspired chemotherapy arm (P = 0.07). The five years DFS in the allo-HCT arm was 58.8% as compared to 71.9% in the pediatric-inspired chemotherapy arm (P = 0.07). The relapse rate in the allo-HCT cohort was 30.58% compared to 21.68% in the pediatric-inspired chemotherapy arm (P = 0.16). The NRM in the allo-HCT cohort was 10.59 as compared to 6.45 in the pediatric-inspired chemotherapy arm (P = 0.3). CONCLUSION: For adolescent and adult patients with Ph-negative ALL, pediatric-inspired chemotherapy resulted in higher OS compared to allo-HCT.

Frontline-matched sibling donor transplant of aplastic anemia patients using primed versus steady-state bone marrow grafts.

Priming donors with G-CSF before BM harvest is reported to improve engraftment and GvHD in recipients. These effects are highly desirable when transplanting patients with non-neoplastic hematologic diseases, particularly AA patients. Here we retrospectively report the outcomes of 39 AA patients receiving a primed BM graft from MSD to 43 patients receiving a steady-state BM graft from MSD, otherwise transplanted using a uniform transplant platform. The graft had higher TNC and CD34 cell concentrations in the primed group (p < 0.001), and that was reflected in higher TNC and CD34 doses per kilogram of recipient in the primed group (p = 0.004 and 0.03, respectively). The OS for primed BM graft recipients was 97.4% and 78.9% for the steady-state BM graft recipients, p-value = 0.01. The cumulative incidence of death without GF was 2.6% in the primed group and 16.3% in the steady-state group, p-value = 0.03. There was no difference in GvHD incidence between the two groups. We confirm that priming improved the TNC and CD34 graft concentration and cell dose; this evidence along with other reported studies constitute reasonable evidence to prove that BM priming improve engraftment. We observed no increase in GvHD using primed BM graft.

Improved survival in adolescents and young adults (AYA) patients aged 14-55 years with acute lymphoblastic leukemia using pediatric-inspired protocol - a retrospective analysis of a real-world experience in 79 of patients treated at a national tertiary care referral center.

BACKGROUND: Treating adolescents and young adults (AYA) patients with acute lymphoblastic leukemia (ALL) using pediatric-inspired protocols have shown improvement in outcomes. Most data available in the literature of such protocols is derived from well-controlled clinical trials. This report aims to provide a real-world experience from using a pediatric-inspired protocol in ALL-AYA population in larger number of patients treated at a national tertiary care referral center. METHODS: Newly diagnosed Philadelphia negative ALL-AYA patients ages between 14 and 55 years of age were treated on an institutional protocol (AYA-15 protocol) adopted from a modified version of Children's Cancer Group (CCG) 1900 protocol. At the time of this publication, a total of 79 patients were treated using the AYA-15 protocol between 2015 and 2020). Event-free survival (FFS), disease-free survival (DFS), and overall survival (OS) were analyzed using cumulative incidence and Kaplan-Meier methods. RESULTS: The median age at diagnosis was 18 years (14-51 years) with 63% male patients. Complete remission (CR) at day 28 of induction was achieved in 88.6% of which 73.4% were minimal residual disease (MRD) negative. At a median follow up of 5 years, EFS, DFS and OS were 57.5%, 69.2% and 75.8% respectively. Toxicities were within the expected range with infections and transaminitis being the most common adverse events. CONCLUSION: Our single-center experience real-world data in treating AYA-ALL patients with pediatric-inspired protocol demonstrates encouraging results of high survival rate and excellent tolerability for patients aged 18-55 years.

Full Dose Cyclophosphamide with the Addition of Fludarabine for Matched Sibling Transplants in Severe Aplastic Anemia.

The recommended therapy for severe aplastic anemia (SAA) in younger patients with a matched sibling donor (MSD) is allogeneic hematopoietic cell transplantation (allo-HCT). A number of conditioning regimens and protocols have been used for these patients. Here we report a homogeneous cohort of SAA patients receiving a uniform transplantation protocol. This study is a retrospective analysis of 82 consecutive patients with SAA who underwent MSD allo-HCT at a single center. The median duration of follow-up for survivors was 100 months, the 10-year overall survival (OS) was 87.5%, and the 10-year event-free survival was 75.3%. The OS was 97.4% for "mobilized" bone marrow (BM) graft recipients and 78.9% for "nonmobilized" BM graft recipients (P = .01. The cumulative incidence of acute graft-versus-host disease (GVHD) was 25.6%, that of chronic GVHD was 27.16%, and that of graft failure was 16.2%. Recipient age ≥30 years and transplantation at >6 months after SAA diagnosis were associated with a increased risk of events. In the presence of a fully matched sibling donor, allo-HCT with a mobilized BM graft and fludarabine-cyclophosphamide conditioning is an efficacious and safe approach. Early transplantation is associated with a better outcome, emphasizing the importance of not delaying transplantation in these patients. Prospective trials are needed to determine the optimal regimen.

Systematic Review/Meta-Analysis on Efficacy of Allogeneic Hematopoietic Cell Transplantation in Sickle Cell Disease: An International Effort on Behalf of the Pediatric Diseases Working Party of European Society for Blood and Marrow Transplantation and the Sickle Cell Transplantation International Consortium.

Sickle cell disease (SCD) affects more than 300,000 children annually worldwide. Despite improved supportive care, long-term prognosis remains poor. Allogeneic hematopoietic cell transplantation (allo-HCT) is the sole validated curative option, resulting in sustained resolution of the clinical phenotype. The medical literature on allo-HCT for SCD is largely limited to children. Recent studies have evaluated allo-HCT efficacy in adults. Here, we conducted a systematic review/meta-analysis to assess the totality of evidence on the efficacy, or lack thereof, of allo-HCT in treating SCD. We performed a comprehensive literature search using PubMed/Medline, Embase, and Cochrane library databases on November 13, 2019. Four authors independently extracted data on clinical outcomes related to benefits (overall survival [OS] and disease-free survival [DFS]) and harms (acute graft-versus-host disease [aGVHD], chronic graft-versus-host disease [cGVHD], nonrelapse mortality [NRM], and graft failure [GF]). Our search identified a total of 1906 references. Only 33 studies (n= 2853 patients) met our inclusion criteria. We also performed a subset analysis by age. Analyses of all-age groups showed pooled rates of 96% for OS, 90% for DFS, 20% for aGVHD, 10% for cGVHD, 4% for NRM, and 5% for GF. In the pediatric population, pooled rates for OS, DFS, aGVHD, cGVHD, NRM, and GF were 97%, 91%, 26%, 11%, 5%, and 3%, respectively. In adults, pooled rates for OS, DFS, aGVHD, cGVHD, NRM, and GF were 98%, 90%, 7%, 1%, 0%, and 14%, respectively. Our data show that allo-HCT is safe and effective, yielding pooled OS rates exceeding 90%. The high GF rate of 14% in adults is concerning and emphasizes the need to evaluate new strategies.

The outcomes of secondary AML post allogeneic hematopoietic cell transplantation significantly depend on the presence of poor-risk cytogenetic abnormalities.

Secondary acute myeloid leukemia (sAML) includes AML as a complication of an antecedent hematological disorder or a therapy-related AML. Large registry-based data identified sAML as an independent poor-outcome type of AML post allogeneic hematopoietic cell transplantation (allo-HCT). In our study, we tried to define factors affecting outcomes of sAML post allo-HCT, and identify patients with sAML who may truly benefit from allo-HCT. We retrospectively analyzed the data of 64 patients aged (14-61 years) with sAML who received allo-HCT between September 2010 and February 2018 at our institute. Most of the patients were transplanted from matched related donors (MRD; 54, 84.4%). Our results showed that poor-risk cytogenetics were identified in 31 patients (48.4%), and their presence was an indicator of poor overall survival (OS) and disease-free survival (DFS; P-value = .009, and .004, respectively). The cumulative incidence of chronic graft-versus-host disease (cGVHD) was significantly lower in sAML patients with poor-risk cytogenetics (P-value = .003) resulting in a high risk of death without cGVHD in this group of patients (P-value = .02). Besides, GVHD relapse-free survival (GRFS) analysis showed that most of our studied patients experienced either relapse or debilitating grade II-IV cGVHD in the first 2 years post allo-HCT. We conclude that sAML patients with poor-risk cytogenetics have a significantly lower DFS post allo-HCT with a high risk of death without active cGVHD.

Hematopoietic stem cell transplantation in Saudi Arabia between 1984 and 2016: Experience from four leading tertiary care hematopoietic stem cell transplantation centers.

Saudi Arabia is the largest of the Arabian Gulf countries with a total population of 33.41 million as of 2017. This report summarizes the experience from four leading tertiary care hematopoietic stem cell transplantation (HSCT) centers in Saudi Arabia representing more than 90% of all HSCTs performed in the country. Between 1984 and 2016, a total of 6,184 HSCTs were performed. Of these, 3,586 HSCTs were performed in adults and 2,598 HSCTs were performed in pediatric patients. Malignancy was the main indication for transplantation (47%). While most transplants were performed from an identical sibling donor, HSCTs from cord blood, unrelated and, more recently, haploidentical donors have also been performed. Relative shortage of HSCT bed capacity is perceived to be a limiting factor in Saudi Arabia. Lately, more HSCT centers are emerging with rapid growth, which may significantly improve the access to HSCT in the country in the near future.

An update on the molecular pathogenesis and potential therapeutic targeting of AML with t(8;21)(q22;q22.1);RUNX1-RUNX1T1.

Acute myeloid leukemia (AML) with t(8;21)(q22;q22.1);RUNX1-RUNX1T1, one of the core-binding factor leukemias, is one of the most common subtypes of AML with recurrent genetic abnormalities and is associated with a favorable outcome. The translocation leads to the formation of a pathological RUNX1-RUNX1T1 fusion that leads to the disruption of the normal function of the core-binding factor, namely, its role in hematopoietic differentiation and maturation. The consequences of this alteration include the recruitment of repressors of transcription, thus blocking the expression of genes involved in hematopoiesis, and impaired apoptosis. A number of concurrent and cooperating mutations clearly play a role in modulating the proliferative potential of cells, including mutations in KIT, FLT3, and possibly JAK2. RUNX1-RUNX1T1 also appears to interact with microRNAs during leukemogenesis. Epigenetic factors also play a role, especially with the recruitment of histone deacetylases. A better understanding of the concurrent mutations, activated pathways, and epigenetic modulation of the cellular processes paves the way for exploring a number of approaches to achieve cure. Potential approaches include the development of small molecules targeting the RUNX1-RUNX1T1 protein, the use of tyrosine kinase inhibitors such as dasatinib and FLT3 inhibitors to target mutations that lead to a proliferative advantage of the leukemic cells, and experimentation with epigenetic therapies. In this review, we unravel some of the recently described molecular pathways and explore potential therapeutic strategies.

Outcomes of allogeneic hematopoietic cell transplant for acute myeloid leukemia in adolescent patients.

Patients between 14 and 22 years old are underrepresented in both adult and pediatric studies. We analyzed the outcomes of 94 consecutive patients aged between 14 and 22 who underwent myeloablative matched related-donor transplant while in first or second complete remission. We studied the impact of disease type, remission status, ELN risk group, ABO mismatch, time from diagnosis to transplant, patient and donor age, conditioning type, stem cell source, and the year of transplant on transplant outcomes. The cumulative incidences of relapse, NRM, OS, and DFS at 5 years were 42%, 10%, 59%, and 48%, respectively. Absence of ABO mismatch and donor age > 20 were associated with better OS and DFS on univariate and multivariate analysis. The cumulative incidence of aGVHD and cGVHD were 18% and 44%, respectively. Donor age > 20 and peripheral blood stem cell source were significantly associated with higher incidence of cGVHD on univariate and multivariate analysis. Younger patient age was significantly associated with higher incidence of aGVHD. In this age group, the determinants of survival seem to be dependent on donor variables rather on the traditional disease and patient related variables. Relapse still a significant factor for transplant failure while NRM was low.

Improved Outcome of a Pediatric-Inspired Protocol for High-Risk Adolescent and Young Adult Acute Lymphoblastic Leukemia Patients Using Peg-Asparaginase and Escalating Dose of Methotrexate: Tolerability and Outcome.

BACKGROUND: Treatment of acute lymphoblastic leukemia (ALL) in adolescent and young adult (AYA) patients using traditional adult chemotherapy protocols give low overall survival (OS) rates. Data are growing regarding the use of pediatric-inspired chemotherapy protocols in AYA patients with improvement in OS. PATIENTS AND METHODS: To assess efficacy and tolerability of using a pediatric-inspired protocol in AYA patients, we initiated our local prospective trial using a modified version of the Children's Cancer Group 1900 protocol for newly diagnosed high-risk Philadelphia chromosome-negative ALL patients. RESULTS: A total of 40 patients were enrolled in the study (from 2015 to 2018). The median age was 18 years (range, 14-34 years). The complete remission rate after induction was 37 patients [93%] and after a median follow-up of 5 years, OS, disease-free survival (DFS), and event-free survival were 75%, 72%, and 60%, respectively. Use of this protocol was well tolerated with manageable toxicities. Pegylated asparaginase was given to all patients during the induction phase and was well tolerated. CONCLUSION: The use of a pediatric-inspired protocol for high-risk AYA ALL patients was effective and well tolerated with improvement in OS and DFS compared with historical data using adult protocols in such populations.

Physical therapy pathway and protocol for patients undergoing hematopoietic stem cell transplantation: Recommendations from The Eastern Mediterranean Blood and Marrow Transplantation (EMBMT) Group.

BACKGROUND: Patients undergoing hematopoietic stem cell transplantation (HSCT) are often referred for physical therapy (PT) to help improve their quality of life. However, to our knowledge there is no clear PT pathway to guide therapists and patients before, during, and after HSCT. METHODS: A comprehensive literature review was carried out exploring the role and benefits of PT in HSCT patients. The current evidence was comlimented with recommendations and opinions from the experts in the field, which included PT's and hematology consultants from PTAGVHD and the EMBMT group. RESULT: A clear pathway and protocol as a working guide for rehabilitation professionals working with the HSCT patient's was developed. CONCLUSION: This paper not only reviews the current evidence on safe PT practice but also puts forward a protocol and pathway for HSCT rehabilitation, highlights the importance of individualized exercise intervention for HSCT patients, and outlines safe practice guidelines for the physical therapists working in this field.

Prognostic role of KIR genes and HLA-C after hematopoietic stem cell transplantation in a patient cohort with acute myeloid leukemia from a consanguineous community.

NK cell activity is tuned by a balance of activating and inhibitory signals transmitted via their respective receptors, including killer immunoglobulin-like receptors (KIRs). The impact of NK cells on graft-versus-leukemia following hematopoietic stem cell transplantation (HSCT) is well established. These effects sometimes lead to GvHD. The link between KIR/HLA interaction and GvHD remains unclear. Herein, we studied the impact of the KIR/HLA interaction on HSCT outcomes in a longitudinal follow-up study of a highly consanguineous HLA-matched related cohort. Peripheral blood DNA was collected from HSCT donor-recipient pairs (n = 87), including 41 AML pairs. KIR and HLA were genotyped and significant results were only measured when matching KIR (donor) with HLA (recipients). GvHD was observed in 47% of patients. KIR2DL1_C2 and 2DS2_C1 (P = 0.02 and 0.04, respectively) matching was associated with an increased incidence of acute GvHD in AML donor-recipient pairs. The rate of chronic GvHD also rose in AML patients who were matched for KIR2DS1_C2 (P = 0.004) and had either KIR2DL2 or KIR2DS2 (P = 0.03). In conclusion, matching of KIR2DL1, 2DS1, and 2DS2 in donors with their HLA-C ligands in recipients is associated with increased GvHD, and holds potential for selection of HSCT donors.