Stem Cell Transplantation For Leukemia Research Articles

Improving outcomes of hematopoietic stem cell transplant for leukemia in children and young adults in resource-limited setting

IntroductionAllogeneic hematopoietic stem cell transplantation (HSCT) is a curative approach in patients with relapsed and high-risk leukemia. This retrospective analysis aimed to investigate outcomes and risk factors associated with HSCT in children and young adults with hematological malignancies in a resource-limited setting. MethodsWe retrospectively evaluated 48 pediatric and young adult patients diagnosed with hematological malignancies who underwent HSCT at our institution between April 2017 and Jan 2023. ResultThe median age of the cohort was 10 years (6 months - 21 years), and the majority of patients underwent transplants for acute lymphoblastic leukemia (ALL) (n = 24; 50 %) and acute myeloid leukemia (n = 18; 37.5%). Median time to neutrophil and platelet engraftment were 15 days (range 9–28) and 18 days (range 9–40), respectively. One patient had primary graft failure. Cytomegalovirus reactivation occurred in 21 patients (43.8%). Seventeen patients received escalated donor lymphocyte infusion (DLI). With a median follow-up of 902 days (52–2490), the probability of event free survival and overall survival (OS) was 65.9% and 69.4%. OS for lymphoid and myeloid malignancies were 64.7% and 75.2%, respectively. Kaplan-Meier probabilities of OS for patients in first complete remission (CR), CR2, CR3, or with refractory disease were 80%, 76.2%, 0%, and 40%, respectively (p = 0.02). OS of the patients undergoing matched sibling donor (n = 17) or haploidentical HSCT (n = 31) was 70.6% and 69%, respectively (p = 0.989). ConclusionsOur study demonstrates excellent outcomes of patients with hematological malignancies undergoing allogeneic HSCT with similar outcomes in HLA-identical sibling donors and haploidentical first-degree family donors. Prophylactic DLI might be considered in patients with high-risk leukemia to prevent relapse, including ALL.

Ovarian function and spontaneous pregnancy after hematopoietic stem cell transplantation for leukemia before puberty: An L.E.A. cohort study

Ovarian function and spontaneous pregnancy after hematopoietic stem cell transplantation for leukemia before puberty: An L.E.A. cohort study

Trends in hematopoietic stem cell transplantation for leukemia, lymphoma and multiple myeloma in the United States: 2016 to 2020.

e19059 Background: Hematopoietic stem cell transplantation (HSCT) is a core component of the standard of care for many patients with leukemia, lymphoma and multiple myeloma. We aim to evaluate the trend in HSCT for patients with leukemia, lymphoma, and myeloma in the United States. Methods: This is a retrospective cross-sectional study of transplant activity performed at HSC transplant centers in the United States from January 2016 to December 2020 based on the reports submitted to the Center for International Bone Marrow Transplant Research (CIBMTR). CIBMTR transplant data were evaluated for trends in number of transplant, donor type, cell source and age of patients with leukemia, lymphoma and myeloma who received stem cell transplantation. Results: A total of 87,723 patients with leukemia, lymphoma and myeloma received stem cell transplantation during the study period. The transplant recipients were 0-17 years (4.1%), 18-64 years (66.7%) and ≥ 65 years (29.2%). Indication for the transplantations were multiple myeloma (44.7%), Hodgkin lymphoma (5.5%), non-Hodgkin lymphoma (19.4%), acute lymphoblastic leukemia (8%), acute myeloid leukemia (19.4%), chronic myeloid leukemia (1.4%) and other leukemias (1.5%). Donor types were autologous (64.8%), allogeneic related (16.3%) and unrelated (18.9%). Peripheral blood was the most common cell source (91.6%), followed by bone marrow (6.2%) and cord blood (2.2%). Eighty six percent of all cord blood transplantation were performed for acute leukemias. The total number of transplantation trended up across all disease categories from 2016 to 2019 but slightly declined in 2020. Allogeneic HCT for non-Hodgkin lymphoma and multiple myeloma declined by 11% and 50% respectively between 2016 and 2020. Conclusions: The COVID pandemic has minimal impact on HSCT in the US. HSCT is more commonly performed for myeloma than for patients with lymphoma or leukemia. Most transplants are autologous with peripheral blood as the cell source. There is a progressive decline in the use of allogeneic HSCT for myeloma and non-Hodgkin lymphoma possibly due to emerging novel therapies. [Table: see text]

HAX1-related congenital neutropenia: Long-term observation in paediatric and adult patients enrolled in the European branch of the Severe Chronic Neutropenia International Registry (SCNIR).

HAX1-related congenital neutropenia (HAX1-CN) is a rare autosomal recessive disorder caused by pathogenic variants in the HAX1 gene. HAX1-CN patients suffer from bone marrow failure as assessed by a maturation arrest of the myelopoiesis revealing persistent severe neutropenia from birth. The disorder is strongly associated with severe bacterial infections and a high risk of developing myelodysplastic syndrome or acute myeloid leukaemia. This study aimed to describe the long-term course of the disease, the treatment, outcome and quality of life in patients with homozygous HAX1 mutations reported to the European branch of the Severe Chronic Neutropenia International Registry. We have analysed a total of 72 patients with different types of homozygous (n = 68), compound heterozygous (n = 3), and digenic (n = 1) HAX1 mutations. The cohort includes 56 paediatric (<18 years) and 16 adult patients. All patients were initially treated with G-CSF with a sufficient increase in absolute neutrophil counts. Twelve patients required haematopoietic stem cell transplantation for leukaemia (n = 8) and non-leukaemic indications (n = 4). While previous genotype-phenotype reports documented a striking correlation between two main transcript variants and clinical neurological phenotypes, our current analysis reveals novel mutation subtypes and clinical overlaps between all genotypes including severe secondary manifestations, e.g., high incidence of secondary ovarian insufficiency.

Ovarian Function and Spontaneous Pregnancy After Hematopoietic Stem Cell Transplantation for Leukemia Before Puberty: An L.E.A. Cohort Study

Ovarian function impairment and infertility are among the most frequent late effects after hematopoietic stem cell transplantation (HSCT). The aim of this study was to evaluate ovarian function, occurrence of premature ovarian insufficiency (POI), and spontaneous pregnancy in a large cohort of adult survivor women who had undergone HSCT for leukemia before puberty. We conducted a retrospective observational study in women from the national cohort L.E.A., the long-term French follow-up program after childhood leukemia. The median follow-up duration was 18 years (14.2-23.3) after HSCT. Among 178 women, 106 (60%) needed pubertal induction with hormone substitution treatment, whereas 72 (40%) had spontaneous menarche. After spontaneous menarche, 33 (46%) developed POI, mostly within 5 years of HSCT. Older age at time of HSCT and cryopreservation of ovarian tissue appeared as significant risk factors for POI. More than 65% of patients who underwent HSCT before the age of 4.8 years had spontaneous menarche, and almost 50% didn't have POI at last evaluation, whereas more than 85% with HSCT after the age of 10.9 years didn't have spontaneous menarche and needed induction of puberty with hormone replacement therapy. Twenty-two women (12%) had at least one spontaneous pregnancy, with 17 live-births, 14 miscarriages, 4 legal abortions, and 2 therapeutic abortions. These results add supplementary data to better counsel patients and their families on the chances of ovarian residual function and pregnancy after HSCT, as well as on the potential interest of fertility preservation.

Progress of heterozygosity loss in HLA region after allogeneic stem cell transplantation for leukemia

Progress of heterozygosity loss in HLA region after allogeneic stem cell transplantation for leukemia

Synthesis of self-management strategies used by young adults who have undergone hematopoietic stem cell transplantation: A narrative review.

Hematopoietic stem cell transplantation is frequently used to treat young adults with hematologic cancer. The treatment can cause a range of side effects that require patients to self-manage their symptoms. However, there do not seem to be any studies that review the literature on self-management strategies used by this group. The purpose of this paper is to summarize the self-management strategies used by young adults (18-39 years old) who have received a hematopoietic stem cell transplant for leukemia or lymphoma. A narrative review conducted in the CINAHL, MEDLINE and PsycINFO databases returned 11 papers. An analysis of these data shows that young adults use self-management strategies, including managing their emotions, turning to spiritual beliefs, seeking support from others and changing their behaviours. The results stress the importance of nursing care in supporting these self-management strategies used by young adults who have undergone hematopoietic stem cell transplantation.

Occurrence of quadruple squamous cell carcinoma following allogeneic hematopoietic stem cell transplantation for leukemia: A case report.

The present case study investigated a rare case of quadruple squamous cell carcinoma following allogeneic hematopoietic stem cell transplantation (HSCT) for leukemia. The main aim of the case study was to determine the pathogenesis and provide novel methods for the diagnosis and treatment of similar cases. The presence of genetic mutations in the p53, EGFR, KRAS and BRAF genes were analyzed and the presence of microsatellite instability (MSI) was determined. In addition, the expression levels of the proteins p53 and EGFR were investigated. The results identified a genetic mutation in p53, of which its expression levels were upregulated. In addition, the majority of the tumor tissues presented with MSI. Therefore, the present findings suggested that the genetic mutations in p53 caused by MSI following allogeneic HSCT may promote tumorigenesis. In addition, the expression levels of the EGFR protein were upregulated, leading to an increase in MAPK signaling pathway activation, which may also serve an important role.

Efficacy of low dose antithymocyte globulin on overall survival, relapse rate, and infectious complications following allogeneic peripheral blood stem cell transplantation for leukemia in children

Antithymocyte globulin (ATG) and anti-T lymphocyte globulin (ATLG) have been widely used to prevent graft-versus-host disease (GvHD), each with distinct properties and noninterchangeable doses. However, the optimal dose of ATG in children undergoing allo-PBSCT for leukemia has not yet been established. Therefore, the impact of ATG dose on overall survival (OS), relapse, GvHD, and infectious complications was investigated. Patients administered high dose (unrelated: 7.5 mg/kg, haploidentical: 10.0 mg/kg) and low dose (unrelated: 3.75 mg/kg, haploidentical: 5.0 mg/kg) ATG during two consecutive time periods were compared. There were 78 (39.8%) patients in the low dose group and 118 (60.2%) in the high dose group. OS was superior in the low dose group compared to the high dose group (P = 0.017), and relapse incidence was significantly lower in the low dose group (P = 0.022). Cumulative incidences of acute and chronic GvHD were similar between the groups (P = 0.095 and P = 0.672, respectively). Cytomegalovirus reactivation (70.3% vs. 51.3%, P = 0.007), Epstein-Barr virus reactivation (81.4% vs. 39.7%, P < 0.001), and invasive bacterial infections (12.7% vs. 0%, P = 0.001) post transplant were more frequent in the high dose group compared to the low dose group. Therefore, low dose ATG is more optimal in pediatric allo-PBSCT providing better OS while lowering the risk of relapse and infectious complications.

Haploidentical Hematopoietic Stem Cell Transplantation in Leukemia’s: Experience from a Cancer Center in India

There has been a surge in haploidentical hematopoietic stem cell transplantation (HSCT) in India recently. However, there is a paucity of data on haploidentical HSCT from India. The report is an analysis of data of haploidentical HSCT performed at our center. Analysis of patients with acute leukemia or chronic myeloid leukemia who underwent haploidentical HSCT during 2014-2019 was performed. The graft versus host disease (GVHD) prophylaxis was post-transplant Cyclophosphamide with Mycophenolate-mofetil and Cyclosporine. All patients were transfused peripheral blood stem cells from donors. Overall survival (OS) was calculated using the Kaplan-Meier method. Twenty-one patients underwent haploidentical HSCT. Fourteen-patients were males. The median age of patients was 15years. Fludarabine with total body irradiation was the most common conditioning regimen (n = 15, 71.4%). The median duration for neutrophil and platelet engraftment was 14days. Cumulative incidence of acute and chronic GVHD was 19%, and 38% respectively. The median follow-up was 26months and the two-year OS was 38%. Twelve (57%) patients died during the study period, 8 patients (38%) died from transplant-related mortality (TRM), and 4 from disease relapse. Sepsis was the cause of death in six of the eight TRM. Nine out of 21 patients (42.8%) are leukemia-free on follow-up. Haploidentical HSCT is a promising modality of treatment in patients who have no suitable matched donors. Though the TRM remains high, good disease control was achieved in 42.8% of patients. Multi-drug resistant bacterial infection remains a challenge in performing haploidentical HSCT in developing countries.

Impact of graft-versus-host disease on relapse and survival after allogeneic stem cell transplantation for pediatric leukemia

Graft-versus-host disease (GVHD) occasionally leads to morbidity and mortality but is thought to reduce the risk of relapses in patients with a hematological malignancy. However, information on the effect of GVHD in pediatric leukemia is limited. Using a nationwide registry, we retrospectively analyzed 1526 children who underwent allogeneic stem cell transplantation for leukemia. Grades 0-I acute GVHD were associated with a higher relapse rate at three years after transplantation, at 25.4 and 24.3%, respectively, than grades II, III, or IV acute GVHD at 18.9%, 21.2%, and 2.6%, respectively. In contrast, the overall survival curve of the grades 0 and I GVHD groups (79.0% and 79.5%, respectively) approximated that of the grade II GVHD group (76.3%), and the probability of survival was worst in the severe GVHD groups (66.9% for grade III and 42.5% for grade IV). Chronic GVHD also reduced the relapse risk but conferred no survival advantage. Acute lymphoblastic leukemia was more sensitive to acute GVHD than acute myeloid leukemia (AML) while AML was more sensitive to chronic GVHD. Our study reproduced the preventive effects of GVHD against pediatric leukemia relapses but failed to demonstrate a significant survival advantage.

Management of Recurrent Clostridium difficile Infection During Intensive Chemotherapy and Stem Cell Transplantation for Leukemia: Case with Literature Review

Immunocompromised patients undergoing chemotherapy for hematologic malignancy and hematopoietic stem cell transplant (HSCT) recipients are at increased risk of Clostridium difficile (C. difficile) infection (CDI). The recurrence of infection and its associated morbidity and mortality are due to multiple risk factors. Diarrhea is common in HSCT recipients, but the diagnosis of diarrhea caused by CDI is a therapeutic challenge due to frequent Clostridium difficile colonization with diarrhea secondary to non-infectious causes. The high recurrence rate is a significant challenge in the treatment of immunocompromised patients. Close monitoring of the patients, timely diagnosis, preventive measures, treatment with antibiotics, and the removal of offending agents can help in the management and cure of the disease. We review the literature on management and describe a patient with acute lymphoblastic leukemia (ALL) with multiple recurrences of CDI during leukemia therapy and allogeneic stem cell transplantation for leukemia.

Cytomegalovirus pneumonia and Cryptogenic organizing pneumonia following pediatric stem cell transplantation for leukemia

Cytomegalovirus pneumonia and Cryptogenic organizing pneumonia following pediatric stem cell transplantation for leukemia

Methods for testing the Markov condition in the illness-death model: a comparative study.

Markov three-state progressive and illness-death models are often used in biomedicine for describing survival data when an intermediate event of interest may be observed during the follow-up. However, the usual estimators for Markov models (e.g., Aalen-Johansen transition probabilities) may be systematically biased in non-Markovian situations. On the other hand, despite non-Markovian estimators for transition probabilities and related curves are available, including the Markov information in the construction of the estimators allows for variance reduction. Therefore, testing for the Markov condition is a relevant issue in practice. In this paper, we discuss several characterizations of the Markov condition, with special focus on its equivalence with the quasi-independence between left truncation and survival times in standard survival analysis. New methods for testing the Markovianity of an illness-death model are proposed and compared with existing ones by means of an intensive simulation study. We illustrate our findings through the analysis of a data set from stem cell transplant in leukemia. Copyright © 2016 John Wiley & Sons, Ltd.

Extramedullary relapses after allogeneic stem cell transplantation for leukemia: Clinical characteristics, cumulative incidence and risk factors.

e18005 Background: In acute leukemia (AL) relapse after allogeneic stem cell transplantation (ASCT) is a devastating complication. Although this problem has been well studied in the literature ther...

Chimerism-Based Pre-Emptive Immunotherapy with Fast Withdrawal of Immunosuppression and Donor Lymphocyte Infusions after Allogeneic Stem Cell Transplantation for Pediatric Hematologic Malignancies

The presence of increasing host chimerism or persistent mixed chimerism (MC) after hematopoietic stem cell transplantation for leukemia in children is a predictor of relapse. To reduce the risk of relapse, we prospectively studied post-transplantation chimerism-based immunotherapy (IT) using fast withdrawal of immunosuppression (FWI) and donor lymphocyte infusions (DLI) in children with early post-transplantation MC. Forty-three children with hematologic malignancies at 2 institutions were enrolled prospectively in this study from 2009 until 2012 and were followed for a mean of 42 (SD, 10) months. Twelve patients (28%) were assigned to the observation arm based on the presence of graft-versus-host disease (GVHD) or full donor chimerism (FDC), and 5 (12%) sustained early events and could not undergo intervention. Twenty-six (60%) patients with MC were assigned to IT with FWI, which started at a median of 49 days (range, 35 to 85 days) after transplantation. Fourteen patients proceeded to DLI after FWI. Toxicities of treatment included GVHD, which developed in 19% of patients undergoing intervention, with 1 of 26 (4%) dying from GVHD and 1 (4%) still requiring therapy for chronic GVHD 21 months after DLI. Patients with MC undergoing IT had similar 2-year event-free survival (EFS) (73%; 95% confidence interval (CI), 55% to 91%) compared with patients who achieved FDC spontaneously (83%; 95% CI, 62% to 100%); however, because 50% of all relapses in the IT occurred later than 2 years after transplantation, the EFS declined to 55% (95% CI, 34% to 76%) at 42 (SD, 11) months. There were no late relapses in the observation group. EFS in the entire cohort was 58% (95% CI, 42% to 73%) at 42 (SD, 11) months after transplantation. Evidence of disease before transplantation remained a significant predictor of relapse, whereas development of chronic GVHD was protective against relapse.

41BBL-Based Activation and Expansion of Autologous Natural Killer Cells Results in Enhanced Activity Against Leukemia Including ALL

Childhood leukemia is the most common pediatric malignancy. There are now excellent cure rates for these patients, however outcomes remain poor for those with refractory disease and for those who relapse after standard salvage therapies, with a disease recurrence of approximately 50%. Therefore, development of novel cellular therapies is essential to treat these refractory patients.Natural Killer (NK) cells generated from an allograft contribute to improved disease free survival after Hematopoietic Stem Cell Transplantation for leukemia when there is a KIR mismatch. This effect appears to be particularly potent in the setting of Acute Myelogenous Leukemia (AML) with less benefit demonstrated in Acute Lymphoblastic Leukemia (ALL). Preclinical studies have also suggested that activation and expansion of resting NK cells can enhance NK cell cytotoxicity and eliminate the need for KIR mismatch due to up-regulation of activating receptors. We are currently testing this approach in the clinic following a fully matched allogeneic transplant platform for leukemia. Our aim is to explore whether 41BB ligand (41BBL) and recombinant IL-15 (rIL-15) mediated ex vivo expansion of autologous NK cells results in enhanced activity against AML and ALL. The activation/expansion process may allow for the use of autologous NK cell infusions, thus eliminating the need for allogeneic NK cell donors.To test this hypothesis, we ex vivo expanded and activated NK cells derived from C57BL/6J (B6) mice using artificial Antigen Presenting Cells (aAPCs) containing 41BBL and rIL-15 for 7-14 days. NK cells were co-cultured with murine AML cells (C1498) and murine ALL cells (E2A-PBX) – both on B6 background. Controls included YAC cells (murine T-cell lymphoma cell line sensitive to NK cell killing) as well as Phorbol Myristate Acetate (PMA)/ionomycin. All cells were co-cultured for 5 hours prior to functional assessment of NK cells via CD107a degranulation.NK cells cultured with 41BBL aAPCs and rIL-15 had a 30-fold expansion in numbers (Figure 1) and an increase in purity to approximately 95-98% (NK1.1+, CD3–) by Day 7. In the absence of cytokine or aAPCs, cultured NK cells underwent rapid apoptosis. Functionally, although resting NK cells (harvested prior to assessment) expressed CD107a when cultured with YAC cells and PMA, only minimal degranulation was observed in the presence of autologous AML cells or ALL cells. In contrast, activated and expanded autologous NK cells displayed enhanced activity against ALL, AML, as well as YAC cells, while only minimal levels of CD107a were seen in the absence of targets (Figure 2). In vivo experiments with a single injection of activated and expanded NK cells did not result in prolonged survival of mice bearing either AML or ALL. Assessment of adoptively transferred NK cells demonstrated very transient persistence (<2 days) with no in vivo expansion, suggesting that repeated injections may be necessary for leukemia eradication. Future murine experiments will investigate the effect repeated injections of activated/expanded NK cells and/or the administration of rIL-15 will have on survival and leukemia eradication. In addition, the ability to activate and expand NK cells in culture provides an opportunity for lentiviral-based transduction with chimeric antigen receptor (CAR) vectors. We are currently testing this with a murine CD19 CAR.These experiments suggest that autologous activated and expanded NK cells may serve as a viable cellular therapy for pediatric patients with refractory/relapsed leukemia. As demonstrated in these in vitro experiments, autologous activated/expanded NK cells still show increased targeting of mouse AML and ALL cell lines despite the lack of KIR mismatch. Thus, they may serve as a potential platform for leukemia therapy, including ALL, which appear to be poor targets for resting NK cells. In addition, these cells demonstrate transient persistence in vivo, a potential advantage in the context of redirected cytotoxicity using CAR constructs that target antigens with broader expression in the hematopoietic compartment. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

B-101 Prospects and Strategies for an HIV Cure

Two highly-publicized cures of HIV infection, 1 in an adult who received an allogeneic hematopoietic stem cell transplant for leukemia from a CCR5 delta 32 homozygous donor, and 1 in an infant started on ART within 2 days of birth, have inspired worldwide efforts to cure HIV infection. The recent relapse of HIV infection 3–8 months after stopping ART in 2 allogeneic bone marrow transplant recipients who had cleared HIV from blood is a sobering reminder of the difficulty of eliminating all replication-competent HIV from an infected host. In this special lecture, I will first review major obstacles to curing HIV infection including: (1) persistent viremia despite effective HIV, (2) latent replication-competent proviruses in CD4+ T-cells, (3) HIV diversity and immune escape variants, (4) clonal expansion of HIV-infected cells, and (5) highly-variable and incompletely effective host immune responses to HIV. I will then highlight curative approaches that are being explored: (1) immediate ART after birth in HIV-infected infants, (2) ART in adults during acute/early HIV infection to prevent reservoir expansion and induce post-treatment immune control, (3) latency reversing agents to deplete HIV reservoirs (e.g., romidepsin), (4) reversal of exhaustion of HIV-specific through immune response by targeting inhibitory receptors on T-cells (e.g. anti-PD-L1), (5) antibody- , cell-, and vaccine-based immunotherapies to enhance HIV immune responses, and (6) host modification to confer cellular resistance to HIV replication. Progress towards a cure of HIV infection will undoubtedly occur, but the challenge of developing and delivering effective and scalable therapies for most HIV-infected persons worldwide is a very formidable 1.

Factors affecting receipt of expensive cancer treatments and mortality: evidence from stem cell transplantation for leukemia and lymphoma.

To identify factors that affect whether patients diagnosed with either leukemia or lymphoma receive a stem cell transplant and secondly if receipt of stem cell transplantation is linked to improved survival. California inpatient discharge records (2002-2003) for patients with either leukemia or lymphoma linked with vital statistics death records (2002-2005). Bivariate Probit treatment effects model that accounts for both the type of treatment received and survival while controlling for nonrandom selection due to unobservable factors. Having private insurance coverage and residence in a well-educated county increased the chances a patient with either disease received HSCT. Increasing age and travel distance to the nearest transplant hospital had the opposite effect. Receipt of HSCT had a significant impact on mortality. We found the probability of death was 4.3 percentage points higher for leukemia patients who did NOT have HSCT. Receipt of HSCT reduced the chances of dying by almost 50 percent. The likelihood of death among lymphoma patients who underwent HSCT was almost 5 percentage points lower, a 70 percent reduction in the probability of death. The findings raise concern about access to expensive, but highly effective cancer treatments for patients with certain hematologic malignancies.

A single-center experience of cytomegalovirus infections in Asian pediatric patients undergoing allogeneic hematopoietic stem cell transplant for leukemia in Singapore.

Cytomegalovirus (CMV) infection remains a significant cause of morbidity and mortality in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) despite improved surveillance and the current preemptive approach. Few data on its prevalence in the Asian pediatric population exist. We retrospectively reviewed the prevalence of CMV infections in 33 patients with 37 transplants who received HSCT for leukemia from 1998 to 2008, and who were managed preemptively for infections. In the 37 transplants, 16 patients (43%) had CMV DNAemia. Of the patients who were CMV seropositive before transplant and received stem cells from seropositive donors (R+/D+), 69% had DNAemia; of those who received stem cells from seronegative donors (R+/D-), 36% had CMV DNAemia. Of the patients who were CMV naïve before transplant and received stem cells from seropositive donors (R-/D+), 25% had CMV DNAemia. In CMV-seronegative donor-recipient transplants (R-/D-), 20% of patients had CMV DNAemia. The median time to the first episode of CMV DNAemia was 21 (range: 10-107) days after the transplants, and the median duration of CMV DNAemia was 22 (range: 2-315) days. CMV DNAemia recurred in 44% (7 of 16) of these patients. Only 1 patient developed CMV disease (retinitis). No deaths were related to CMV infections. CMV infection manifesting as DNAemia is a common complication in pediatric patients undergoing allogeneic HSCT for leukemia. Pre-transplant serostatus predicts reactivation risks; invasive CMV disease is rare using the preemptive approach in our patient population.