Telomere length changes in patients undergoing hematopoietic stem cell transplantation.

Telomere length indicates the replicative history of cells, serving as a molecular measure of the replicative potential remaining in cells. To investigate telomere length changes in hematopoietic stem cells, patients undergoing hematopoietic stem cell transplantation (HSCT) were evaluated. Fifteen patients after allogeneic bone marrow transplantation (allo-BMT group), seven patients after autologous peripheral blood stem cell transplantation (auto-PBSCT group), and 39 healthy controls were studied. Telomere length was measured in peripheral mononuclear cells by Southern blot hybridization. There was no significant difference between the allo-BMT and the auto-PBSCT groups. In the allo-BMT group, the mean telomere length of recipients was 2.01 kb shorter than that of their donors (P = 0. 008), and was 1.59 kb shorter than that of age-matched putative normal controls (P = 0.002). Telomere shortening in the allo-BMT group was equivalent to 41.4 years of aging in the donors, and to 52. 4 years of aging in the normal controls. The mean telomere length in the auto-PBSCT group was 2.36 kb shorter than that of the age-matched putative controls (P = 0.043), which was equivalent to 61.5 years of aging in normal controls. The extent of telomere shortening in the allo-BMT group showed a trend to negative correlation with the number of mononuclear cells infused. These findings suggest that hematopoietic stem cells after HSCT lose telomere length and these shortened telomeres may result in a higher incidence of clonal disorders later in life.     

Constitution and telomere dynamics of bone marrow stromal cells in patients undergoing allogeneic bone marrow transplantation

We evaluated the genotypic origin of mesenchymal stem cells (MSC) following sex-mismatched allogeneic bone marrow transplantation (BMT), and investigated the telomere dynamics in MSC in normal individuals and patients after BMT. The study population consisted of 11 patients with hematologic disorders who showed complete chimerism after BMT. Telomere length was measured in MSC using Southern blotting analysis in eight patients and 18 healthy subjects as a control group. Following culture, MSC were identified by the expression of SH2 and SH4, and lack of CD14, CD34, and CD45. All MSC showed the recipient genotype, based on the results of fluorescent in situ hybridization analysis using X-chromosome satellite probes or microsatellite DNA polymorphism analysis. The mean telomere length in MSC from normal controls was 7.2+/-0.53 kb (range, 6.12-7.78), and progressive telomere shortening was seen with age. There was no significant difference in MSC telomere length between the BMT group and age-matched controls. This study confirmed that the MSC isolated from the recipients of allogeneic BMT did not have the donor genotype, despite complete chimerism. Moreover, MSC were demonstrated to show progressive loss of telomere length with age, but the telomeres in MSC were not affected by BMT.     

Accelerated telomere shortening following allogeneic transplantation is independent of the cell source and occurs within the first year post transplant

Telomere shortening has been documented in the blood cells of recipients of allogeneic bone marrow transplants compared with their donors. Allogeneic peripheral blood progenitor cells (PBPCs) have been increasingly used as an alternative to bone marrow. Their advantages include earlier engraftment and immune reconstitution following transplantation. We have measured telomere length of neutrophils and T cells in fully engrafted recipients of allogeneic bone marrow (n = 19) and allogeneic PBPC (n = 17) and also measured sequential telomere length in four patients after transplantation. Overall, significant telomere shortening occurred in recipients in neutrophils (0.3 kb, P < 0.001) and T cells (0.2 kb, P = 0.045). The data demonstrate that first, the degree of shortening was the same for BM and PBPC transplants and was not related to the time taken to engraft neutrophils and platelets and second, telomere shortening occurs in the first year post transplant without further shortening during the period of observation. These data suggest that the superiority of engraftment seen in PBPC transplants is independent of telomere shortening and other mechanisms such as homing or seeding may be more important.     

A percentage analysis of the telomere length in Parkinson's disease patients

Telomeres are the repeated sequences at the chromosome ends which undergo shortening with cell division. The telomere shortening of the peripheral leukocytes is also facilitated by enhanced oxidative stress in various kinds of disease including ischemic heart disease, diabetes mellitus, apoplexy, and Alzheimer's disease. Telomere shortening in Parkinson's disease (PD) has not yet been reported. The pathogenesis for PD is also regarded to be associated with oxidative stress. We investigated 28 Japanese male PD patients ages 47-69. Although we could not find a statistical difference in the mean telomere length of peripheral leukocytes between the PD patients and the control participants, we found the mean telomere lengths to be shorter than 5 kb in only the PD patients and a significant PD-associated decrease in the telomeres with a length ranging from 23.1 to 9.4 kb in the patients in their 50s and 60s. These observations suggest that telomere shortening is accelerated in PD patients in comparison to the normal population.     

Short telomeres are associated with increased carotid atherosclerosis in hypertensive subjects

Recent studies have shown that individuals with shorter telomeres present a higher prevalence of arterial lesions and higher risk of cardiovascular disease mortality. As a group, patients with high blood pressure are at an increased risk for cardiovascular diseases. However, some hypertensive patients are more prone than others to atherosclerotic lesions. The main objective of this study was to examine the relationship between telomere length, as expressed in white blood cells, and carotid artery atherosclerotic plaques in hypertensive males. Data from 163 treated hypertensive men who were volunteers for a free medical examination were analyzed. Extracranial carotid plaques were assessed with B-mode ultrasound. Telomere length was measured from DNA samples extracted from white blood cells. The results of this study show that telomere length was shorter in hypertensive men with carotid artery plaques versus hypertensive men without plaques (8.17+/-0.07 kb versus 8.46+/-0.07 kb; P<0.01). Multivariate analysis showed that in addition to age, telomere length was a significant predictor of the presence of carotid artery plaques. The findings from this study suggest that in the presence of chronic hypertension, which is a major risk factor for atherosclerotic lesions, shorter telomere length in white blood cells is associated with an increased predilection to carotid artery atherosclerosis.     

Long-term follow-up of recipients of allogeneic bone marrow grafts reveals no progressive telomere shortening and provides no evidence for haematopoietic stem cell exhaustion

Summary. Accelerated telomere shortening has been proposed as a possible long‐term risk of allogeneic bone marrow transplantation (allo‐BMT). In this study we monitored telomere length in white blood cells (WBC), granulocytes, and naïve and memory CD4⁺ T lymphocytes in recipients of allo‐BMT at long‐term follow‐up. Peripheral blood was collected from 10 allo‐BMT recipients and donors at a median interval of 18 years after allo‐BMT. Telomere length was determined using Southern blot analysis. Similar to results previously reported at short‐term follow‐up, a small difference in telomere length (0·1–0·3 kb) between recipients and donors was detected in WBC, granulocytes and naïve CD4⁺ T cells. Our data therefore provide no evidence for sustained telomere shortening in leucocytes, and render the possibility of long‐term haematopoietic graft failure unlikely. In addition, we observed two phenomena that may be related to involution of the thymus. First, the number of naïve CD4⁺ T cells in the blood was significantly lower in recipients (0·4 × 10⁹/l) than in donors (0·7 × 10⁹/l) (P < 0·05). Second, telomeres in memory CD4⁺ T cells from recipients were on average 0·6 kb shorter than those from donors (P = 0·01). The latter may be related to the reported rapid peripheral expansion of memory T cells immediately after transplantation.     

Pulmonary tuberculosis in allogeneic hematopoietic stem cell transplantation

Pulmonary tuberculosis (TB) is an endemic infectious disease in Taiwan. A retrospective study was conducted to define clinical manifestations and outcomes of patients with pulmonary TB among hematopoietic stem cell transplantation (HSCT) recipients. We identified eight out of 350 HSCT recipients as having pulmonary TB over a 6-year period. The relative risk of having pulmonary TB after HSCT was 13.1-fold higher than in the general population. There was a trend toward increased risk of having pulmonary TB in allogeneic HSCT as compared to autologous HSCT (4.8 +/- 1.8% vs 0, P = 0.067). All the eight patients with pulmonary TB received allogeneic HSCT and most (seven of eight patients) developed the infection during treatment for GVHD. Computed tomography of the chest was normal in one patient, with the rest showing either interstitial (two patients) or alveolar infiltrates (five patients) at the onset of pulmonary TB. The four fatal cases had an obviously shorter duration between HSCT and onset of infection. Our data suggest that pulmonary TB in HSCT recipients is not uncommon in this endemic area. Therefore, an effective strategy of prophylactic treatment for candidates and recipients of allogeneic HSCT, who may have latent pulmonary TB infection, must be developed.     

Telomeres and telomere dynamics: relevance to cancers of the GI tract

Aberrations in telomere length and telomere maintenance contribute to cancer development. In this article, we review the basic principles of telomere length in normal and tumor tissue and the presence of the two main telomere maintenance pathways as they pertain to gastrointestinal tract cancer. Peripheral blood telomeres are shorter in patients with many types of gastrointestinal tract cancers. Telomere length in tumor DNA also appears to shorten early in cancer development. Tumor telomere shortening is often accompanied by telomerase activation to protect genetically damaged DNA from normal cell senescence or apoptosis, allowing immortalized but damaged DNA to persist. Alternative lengthening of telomeres is another mechanism used by cancer to maintain telomere length in cancer cells. Telomerase and alternative lengthening of telomeres activators and inhibitors may become important chemopreventive or chemotherapeutic agents as our understanding of telomere biology, specific telomere-related phenotypes and its relationship to carcinogenesis increases.     

Telomere length shortening in non-Hodgkin's lymphoma patients undergoing chemotherapy

We investigated telomere length changes in patients with non-Hodgkin's lymphoma (NHL) receiving conventional-dose chemotherapy. Using Southern blot analysis, telomere length was measured in peripheral blood mononuclear cells from five NHL patients at diagnosis, 15 NHL patients after chemotherapy, and 39 healthy controls. Compared with age-matched putative normal controls, telomeres were significantly shorter in NHL patients at diagnosis. Mean telomere length was shorter after chemotherapy than before chemotherapy and was shorter after chemotherapy than in age-matched putative healthy controls. There was no correlation between the extent of telomere shortening and time elapsed after chemotherapy. These findings suggest that in NHL patients hematopoietic stem cells lose telomere length during the recovery period from bone marrow suppression after conventional-dose chemotherapy.     

Fungal infections in recipients of hematopoietic stem cell transplants: results of the SEIFEM B-2004 study--Sorveglianza Epidemiologica Infezioni Fungine Nelle Emopatie Maligne.

BACKGROUND: The purpose of our study was to evaluate the incidence and outcome of invasive fungal infection (IFI) among patients who underwent autologous or allogeneic hematopoietic stem cell transplantation (HSCT) at 11 Italian transplantation centers. METHODS: This cohort-retrospective study, conducted during 1999-2003, involved HSCT patients admitted to 11 tertiary care centers or university hospitals in Italy, who developed IFIs (proven or probable). RESULTS: Among 3228 patients who underwent HSCT (1249 allogeneic HSCT recipients and 1979 autologous HSCT recipients), IFI occurred in 121 patients (overall incidence, 3.7%). Ninety-one episodes (2.8% of all patients) were due to molds, and 30 (0.9%) were due to yeasts. Ninety-eight episodes (7.8%) occurred among the 1249 allogeneic HSCT recipients, and 23 (1.2%) occurred among the 1979 autologous HSCT recipients. The most frequent etiological agents were Aspergillus species (86 episodes) and Candida species (30 episodes). The overall mortality rate was 5.7% among allogeneic HSCT recipients and 0.4% among autologous HSCT recipients, whereas the attributable mortality rate registered in our population was 65.3% (72.4% for allogeneic HSCT recipients and 34.7% for autologous HSCT recipients). Etiology influenced the patients' outcomes: the attributable mortality rate for aspergillosis was 72.1% (77.2% and 14.3% for allogeneic and autologous HSCT recipients, respectively), and the rate for Candida IFI was 50% (57.1% and 43.8% for allogeneic and autologous HSCT recipients, respectively). CONCLUSIONS: IFI represents a common complication for allogeneic HSCT recipients. Aspergillus species is the most frequently detected agent in these patients, and aspergillosis is characterized by a high mortality rate. Conversely, autologous HSCT recipients rarely develop aspergillosis, and the attributable mortality rate is markedly lower. Candidemia was observed less often than aspergillosis among both allogeneic and autologous HSCT recipients; furthermore, there was no difference in either the incidence of or the attributable mortality rate for candidemia among recipients of the 2 transplant types.     

Proliferation and cytolytic function of anti-CD3 + interleukin-2 stimulated peripheral blood mononuclear cells following bone marrow transplantation.

We evaluated the proliferation, cytolytic function, and phenotypic characteristics of anti-CD3 plus interleukin-2 (IL-2) stimulated peripheral blood mononuclear cells (PBMCs) from 44 patients with leukemia or non-Hodgkin's lymphoma (NHL) treated with multiagent chemotherapy or following bone marrow transplantation (BMT). BMT patients had decreased cell growth with only a 1.35 +/- 0.25 (autologous BMT for acute lymphoblastic leukemia [ALL]), 1.24 +/- 0.25 (autologous BMT for NHL), and 0.8 +/- 0.1 (allogeneic BMT for leukemia) mean fold increase by day 5 of culture compared with controls (4.0 +/- 0.4), P less than .001. Anti-CD3 + IL-2 activated cells from patients with ALL and NHL who had received autologous BMT and cells from patients with leukemia who underwent allogeneic BMT were more effective in lysing the natural killer (NK) sensitive target, K562, and the NK-resistant target, Daudi, compared with controls. In contrast, cytolysis of K562 and Daudi by cultured PBMCs from patients with ALL and NHL receiving multi-agent chemotherapy was similar to that of controls. Cultures from BMT recipients had a significant increase in CD16+ (autologous ALL 5.7 +/- 1.5%, P less than .01; autologous NHL 12.4 +/- 3.5%, P less than .001; allogeneic 14.3 +/- 2.9%, P less than .001) and CD56+ cells (autologous ALL 27.6 +/- 12.0%, P less than .01; autologous NHL 39.3 +/- 9.5%, P less than .001; allogeneic 42.7 +/- 7.4%, P less than .001) compared with controls (CD16+ 2.5 +/- 0.4%; CD56+ 6.9 +/- 0.9%). Stimulation of PBMCs with anti-CD3 + IL-2 is effective in generating cells with high cytolytic function post-BMT.     

Premature telomere shortening in polymorphonuclear neutrophils from patients with systemic lupus erythematosus is related to the lupus disease activity

We investigated whether premature telomeric loss occurred in peripheral polymorphonuclear neutrophils (PMN) as well as mononuclear cells (MNC) from patients with systemic lupus erythematosus (SLE). We measured the telomere length of MNC and PMN in 60 SLE patients and 26 sex-, race- and age-matched healthy volunteers by Southern blotting with chemiluminescence method. The possible predisposing factors associated with telomere change were also analysed. We found the telomere length of MNC and PMN shortened with age in different degrees in both SLE and control groups. Compared to the control group, the telomere length was shortened in both SLE-MNC (6.08 kb in SLE versus 6.71 kb in control, P = 0.0008) and PMN (6.24 kb in SLE versus 6.75 kb in control, P = 0.0025). The average reduction in telomere length in SLE patients was equivalent to a premature senescence of 16.5 years in MNC and 13.4 years in PMN. In addition, the accelerated telomere shortening was more prominent in SLE patients younger than 45 years old. SLE disease activity (SLEDAI) contributed remarkably to the accelerated telomere erosion, at least in PMN. Moreover, the telomere length of MNC was significantly shorter than PMN in the same SLE patients with leukopenia and lymphopenia. These data suggested that MNC and PMN from patients with SLE displayed premature and accelerated telomere shortening that SLE is an independent factor for it.     

Early hematopoietic reconstitution after clinical stem cell transplantation: evidence for stochastic stem cell behavior and limited acceleration in telomere loss

Our inability to purify hematopoietic stem cells (HSCs) precludes direct study of many aspects of their behavior in the clinical hematopoietic stem cell transplantation (HSCT) setting. We indirectly assessed stem/progenitor cell behavior in the first year after HSCT by examining changes in neutrophil telomere length, X-inactivation ratios, and cycling of marrow progenitors in 25 fully engrafted allogeneic HSCT recipients. Donors were sampled once and recipients at engraftment and 2 to 6 months and 12 months after HSCT. Telomere length was measured by an in-gel hybridization technique, X-inactivation ratios were measured by the human androgen receptor assay, and cell cycle status was determined by flow cytometric analysis of pyronin Y- and Hoechst 33342-stained CD34(+)CD90(+) and CD34(+)CD90(-) marrow cells. Compared with their donors, recipients' telomeres were shortened at engraftment (-424 base pairs [bp]; P <.0001), 6 months (-495 bp; P =.0001) after HSCT, and 12 months after HSCT (-565 bp; P <.0001). There was no consistent pattern of change in telomere length from 1 to 12 months after HSCT; marked, seemingly random, fluctuations were common. In 11 of 11 informative recipients, donor X-inactivation ratios were faithfully reproduced and maintained. The proportion of CD34(+)CD90(+) progenitors in S/G(2)/M was 4.3% in donors, 15.7% at 2 to 6 months (P <.0001) after HSCT, and 11.5% at 12 months after HSCT (P <.0001, versus donors; P =.04, versus 2-6 months). Cycling of CD34(+) CD90(-) progenitors was largely unchanged. We infer that (1) HSCT-induced accelerated telomere loss is temporary and unlikely to promote graft failure or clonal hematopoietic disorders and (2) the striking fluctuations in telomere length and variation in pattern of telomere loss reflect stochastic determination of HSC fate after HSCT.     

Telomere biology in hematopoiesis and stem cell transplantation

Telomeres are long (TTAGGG)_n nucleotide repeats and an associated protein complex located at the end of the chromosomes. They shorten with every cell division and, thus are markers for cellular aging, senescence, and replicative capacity. Telomere dysfunction is linked to several bone marrow disorders, including dyskeratosis congenita, aplastic anemia, myelodysplastic syndrome, and hematopoietic malignancies. Hematopoietic stem cell transplantation (HSCT) provides an opportunity in which to study telomere dynamics in a high cell proliferative environment. Rapid telomere shortening of donor cells occurs in the recipient shortly after HSCT; the degree of telomere attrition does not appear to differ by graft source. As expected, telomeres are longer in recipients of grafts with longer telomeres (e.g., cord blood). Telomere attrition may play a role in, or be a marker of, long term outcome after HSCT, but these data are limited. In this review, we discuss telomere biology in normal and abnormal hematopoiesis, including HSCT.     

Premature cardiovascular disease after allogeneic hematopoietic stem-cell transplantation

We assessed incidence and risk factors of cardiovascular events in 265 patients undergoing allogeneic hematopoietic stem-cell transplantation (HSCT) between 1980 and 2000 and who survived at least 2 years. Results were compared with a cohort of 145 patients treated during the same period with autologous HSCT. The median age of patients with allogeneic HSCT at last follow-up was 39 years, and median follow-up was 9 years. Eighteen (6.8%) patients after allogeneic and 3 (2.1%) patients after autologous HSCT experienced an arterial event. The cumulative incidence of first arterial event after allogeneic HSCT was 22.1% (95% CI, 12.0-40.9) at 25 years. The cumulative incidence 15 years after allogeneic HSCT was 7.5% as compared with 2.3% after autologous HSCT. Adjusting for age, risk of an arterial event was significantly higher after allogeneic HSCT (RR 6.92; P =.009). In multivariate analysis, allogeneic HSCT (RR: 14.5; P =.003), and at least 2 of 4 cardiovascular risk factors (hypertension, dyslipidemia, diabetes, obesity) (RR: 12.4; P =.02) were associated with a higher incidence of arterial events after HSCT. Thus, long-term survivors after allogeneic HSCT are at high risk for premature arterial vascular disease. HSCT might favor the emergence of established risk factors, such as hypertension, diabetes, and dyslipidemia.     

Association between telomere length and heart disease in a narrow age cohort of older people

Telomere shortening is a feature of cellular ageing common to a range of human tissues. Shorter telomeres are associated with an increased likelihood of mortality, including death from heart disease. We examined the association between telomere length and heart disease (present in 33%) in a well-characterised, narrow age cohort of older people (n=190, all born in 1921), and tested for any concomitant effects of medication use. Mean telomere length was significantly shorter in participants who reported heart disease (p=.001). Participants with ischemic changes on ECG had shorter telomere lengths (6.67 versus 7.65 kb, p=.021) after adjusting for other ECG abnormalities. This finding adds to the growing body of evidence for an association between telomere shortening and ischemic heart disease. Telomere shortening in peripheral blood leukocytes is a promising index of ischemic heart disease risk in older people and deserves further investigation as a potential mechanism.     

An analysis of telomere length in sarcoidosis

We investigated telomere (terminal restriction fragment [TRF]) length in 111 patients with sarcoidosis regarding both the mean TRF length and the telomere length distribution. A significant decrease was observed in the mean TRF length in sarcoidosis patients in comparison to the age-matched controls, whereas a decreased telomere length was only associated with age in men. The mean TRF shortening seemed to be accelerated in men in their 30s and 50s and in women in their 40s and 50s. We also found a significant decrease with age of telomeres with lengths of 9.4-6.6 kb in men and women in their 20s and an increase of telomeres with lengths of 4.4-2.3 kb in men and women in their 20s and in men in their 50s in sarcoidosis patients versus in the controls who were in their 20s and 50s. These findings suggest the occurrence of age-advanced changes in telomere length in patients with sarcoidosis, regardless of the patient age at the onset of sarcoidosis.     

Telomere shortening in patients with plasma cell disorders

OBJECTIVES: Telomeres are essential for maintaining chromosomal integrity; their shortening is associated with chromosome instability. The aim of this work was to study telomere length (TL) on bone marrow (BM) cells from patients with multiple myeloma (MM) and monoclonal gammopathy of undetermined significance (MGUS). METHODS: Thirty-one MM patients: 12 at diagnosis (D), 11 at relapse (R) and eight at remission (RE) and two cases with MGUS were studied. TL based on terminal restriction fragment (TRF) assay was evaluated. Cytogenetic and molecular cytogenetic analyses were performed. Telomeric associations (TAs) on BM metaphases were also studied. RESULTS: TRF analysis in total MM patients showed a mean TRF peak value (5.20 +/- 0.35 kb) shorter than those observed in controls (8.5 +/- 0.5 kb) (P < 0.001). Moreover, TRF at D and R showed a significant telomere shortening (P < 0.001), with TL restored at RE. A strong correlation with the percentage of BM plasma cell infiltration (BMPCI) (rK = -0.540; P = 0.002) was found. Patients with abnormal karyotypes (AK) had significantly shorter TRFs than that observed in MM patients with normal karyotypes (P < 0.05). TRFs in MGUS patients did not differ with respect to controls. TA analysis showed an increased percentage in MM (19.46 +/- 1.98%) with respect to MGUS (6.12 +/- 1.87%) and normal BM cells (2.00 +/- 0.93%) (P < 0.001). CONCLUSIONS: MM patients showed a significant reduction in TL (> 60% of BMPCI and AK), suggesting a probable association with clinical evolution. Moreover, our findings support the idea that telomere shortening usually leads to increased frequencies of TAs and chromosome instability.     

Increased telomerase activity and decreased telomere length in genital condylomata acuminata

Our objective was to find a possible correlation between telomerase activity, mean telomere length and human papillomavirus (HPV) presence and type in genital condylomata acuminata. Fifteen biopsies from women with genital condylomata acuminata and nine control tissue samples were tested for telomerase activity, mean telomere length, and HPV presence and type. All condylomata exhibited telomerase activity, compared to 78% of the control samples. The mean telomere length of condylomata was significantly (P<0.002) shorter compared to telomere length in control tissue samples. All condylomata lesions were infected with HPV types 6/11, and more than half had additional infection with HPV 16/18. Mixed HPV 6/11 with 16/18 infection correlated with shorter telomeres than presence of HPV 6/11 alone in the lesions (4.68 +/- 0.44 kb vs 4.97 +/- 0.57 kb). None of the control tissue samples showed presence of HPV DNA. Telomerase activity may be a marker of proliferation rather than malignancy, whereas the mean telomere length could better serve as a marker for the progression of HPV lesions toward malignancy.     

Effect of allogeneic hematopoietic stem cell transplantation from matched siblings or unrelated donors during the first complete remission in patients with cytogenetically normal acute myeloid leukemia

We retrospectively examined the impact of hematopoietic stem cell transplantation (HSCT) during the first complete remission (CR1) in 81 patients with cytogenetically normal acute myeloid leukemia (CN-AML). Eligible patients were divided into three subgroups: HSCT recipients with allogeneic sibling or matched unrelated donors (MUD) (allogeneic HSCT, n = 47), recipients of autologous HSCT (n = 12), and patients receiving chemotherapy alone (n = 22). We examined factors associated with overall survival (OS) in these patients, focusing particularly on the effect of allogeneic HSCT. Comparing to those receiving chemotherapy alone, patients in the allogeneic HSCT group had significantly better OS, which was independent of the presence of comorbidities. Furthermore, patients who received allogeneic sibling HSCT had the best OS and disease-free survival (DFS). Patients who received MUD HSCT also had significant advantage in DFS but not in OS, when compared with patients in the chemotherapy group. The study results suggest that patients with CN-AML in CR1 who are eligible for HSCT may have a survival benefit from HSCT, especially the allogeneic HSCT. We suggest that future studies employ molecular classification of AML to better define the benefits of HSCT during CR1 in patients with CN-AML.