Quality-adjusted time without symptoms or toxicity analysis of haploidentical-related donor vs.identical sibling donor hematopoietic stem cell transplantation in acute myeloid leukemia

Objective:We aimed to compare the quality-adjusted time without symptoms or toxicity(Q-TWiST)in acute myeloid leukemia(AML)patients who received haploidentical-related donor(HID)and identical sibling donor(ISD)hematopoietic stem cell transplantation(HSCT).Methods:Five clinical health states were defined:toxicity(TOX),acute graft-versus-host disease(GVHD),chronic GVHD(cGVHD),time without symptoms and toxicity(TWiST)and relapse(REL).The equation used in this study was as follows:Q-TWiST=UTOX×TOX+UTWiST×TWiST+UREL×REL+UaGVHD×aGVHD+UcGVHD×cGVHD.Results:A total of 239 AML patients were enrolled.We established a mathematical model,i.e.,Q-TWiST HID HSCT>Q-TWiST ISD HSCT,to explore the range of utility coefficients satisfying the inequality.Based on the raw data,the utility coefficient is equivalent to the following inequality:10.57067UTOX-46.27733UREL+105.9374+3.388078UaGVHD-210.8198UcGVHD>0.The model showed that when UTOX,UREL,and UaGVHD were within the range of 0-1,as well as when UcGVHD was within the range of 0-0.569,the inequality Q-TWiST HID HSCT>Q-TWiST ISD HSCT was valid.According to the results of the ChiCTR1800016972 study,the median coefficients of TOX,acute GVHD(aGVHD),and cGVHD were 0.56(0.41-0.76),0.56(0.47-0.72),and 0.54(0.37-0.79),respectively.We selected a series of specific examples of the coefficients,i.e.,UTOX=0.5,UREL=0.05,UaGVHD-0.5,and UcGVHD-0.5.The Q-TWiST values of ISD and HID HSCT were 896 and 900 d,respectively(P=0.470).Conclusions:We first observed that Q-TWiST was comparable between AML patients receiving HID HSCT and those receiving ISD HSCT.

Hematopoietic stem cell transplantation for auto immune rheumatic diseases

Stem cells have their origins in the embryo and during the process of organogenesis, these differentiate into specialized cells which mature to form tissues. In addition, stem cell are characterized by an ability to indefinitely self renew. Stem cells are broadly classified into embryonic stem cells and adult stem cells. Adult stem cells can be genetically reprogrammed to form pluripotent stem cells and exist in an embroyonic like state. In the early phase of embryogenesis, human embryonic stem cells only exist transiently. Adult stem cells are omnipresent in the body and function to regenerate during the process of apoptosis or tissue repair. Hematopoietic stem cells(HSC) are adult stem cells that form blood and immune cells. Autoimmune responses are sustained due to the perennial persistence of tissue self autoantigens and/or auto reactive lymphocytes. Immune reset is a process leading to generation of fresh self-tolerant lymphocytes after chemotherapy induced elimination of self or autoreactive lymphocytes. This forms the basis for autologous HSC transplantation(HSCT). In the beginning HSCT had been limited to refractory autoimmune rheumatic diseases(AIRD) due to concern about transplant related mortality and morbidity. However HSCT for AIRD has come a long way with better understanding of patient selection, conditioning regime and supportive care. In this narrative review we have examined the available literature regarding the HSCT use in AIRD.

COVID-19 impact in Crohn’s disease patients submitted to autologous hematopoietic stem cell transplantation

BACKGROUND Severe acute respiratory syndrome coronavirus 2 is the virus responsible for coronavirus disease 2019(COVID-19),a disease that has been blamed for inducing or exacerbating symptoms in patients with autoimmune diseases.Crohn's disease(CD)is an inflammatory bowel disease that affects genetically susceptible patients who develop an abnormal mucosal immune response to the intestinal microbiota.Patients who underwent hematopoietic stem cell transplantation(HSCT)are considered at risk for COVID-19.AIM To describe for the first time the impact of COVID-19 in CD patients who had undergone autologous,non-myeloablative HSCT.METHODS In this descriptive study a series of 19 patients were diagnosed with positive COVID-19.For two patients there were reports of the occurrence of two infectious episodes.Parameters related to HSCT,such as time elapsed since the procedure,vaccination status,CD status before and after infection,and clinical manifestations resulting from COVID-19,were evaluated.RESULTS Among the patients with COVID-19,three,who underwent Auto HSCT less than six months ago,relapsed and one,in addition to the CD symptoms,started to present thyroid impairment with positive anti-TPO.Only one of the patients required hospitalization for five days to treat COVID-19 and remained in CD clinical remission.Nine patients reported late symptoms that may be related to COVID-19.There were no deaths,and a statistical evaluation of the series of COVID-19 patients compared to those who did not present any infectious episode did not identify significant differences regarding the analyzed parameters.CONCLUSION Despite the change in CD status in three patients and the presence of nine patients with late symptoms,we can conclude that there was no significant adverse impact concerning COVID-19 in the evaluated patients who underwent HSCT to treat CD.

Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation

Leukemia relapse is still the leading cause of treatment failure after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL). Relapsed patients with BALL after allo-HSCT have a very short median survival. Minimal residual disease (MRD) is predictive of forthcoming hematological relapse after hematopoietic stem cell transplantation (HSCT);furthermore, eliminating MRD effectively prevents relapse. Donor lymphoblastic infusion (DLI) is the main established approach to treat B-ALL with MRD after allo-HSCT. However, about one-third of patients with MRD are non-responsive to DLI and their prognosis worsens. Although donor-derived cluster of differentiation (CD)19-directed chimeric antigen receptor-modified (CAR) T cells (CART19s) can potentially cure leukemia, the efficiency and safety of infusions with these cells have not yet been investigated in patients with MRD after HSCT. Between September 2014 and February 2018, six patients each received one or more infusions of CART19s from HSCT donors. Five (83.33%) achieved MRD-negative remission, and one case was not responsive to the administration of CAR T cells. Three of the six patients are currently alive without leukemia. No patient developed acute graft-versus-host disease (aGVHD), and no patient died of cytokine release syndrome. Donor-derived CAR T cell infusions seem to be an effective and safe intervention for patients with MRD in B-ALL after allo-HSCT and for those who were not responsive to DLI.

Prognostic value of ^(18)F-fluorodeoxyglucose positron emission tomography using Deauville criteria in diffuse large B cell lymphoma treated with autologous hematopoietic stem cell transplantation

Objective: High-dose chemotherapy(HDC) followed by autologous hematopoietic stem cell transplantation(auto-HSCT) plays an important role in improving outcomes of diffuse large B cell lymphoma(DLBCL) patients.18 F-fluorodeoxyglucose(18 F-FDG) positron emission tomography(PET)/computed tomography(CT) has been widely accepted in response assessment and prediction of prognosis in DLBCL. Here, we report the value of 18 FFDG PET/CT pre-and post-HSCT in predicting outcomes of patients with DLBCL.Methods: DLBCL patients who had PET/CT scan before and after HSCT were included. PET results were interpreted based upon Deauville criteria. The prognostic value of 18 F-FDG PET/CT in auto-HSCT was evaluated.Results: Eighty-four patients were enrolled. In univariate analysis, pre-and post-HSCT PET findings were correlated with 3-year progression-free survival(PFS) [hazard ratio(HR)=4.391, P=0.001; HR=7.607, P<0.001] and overall survival(OS)(HR=4.792, P=0.008; HR=26.138, P<0.001). Patients receiving upfront auto-HSCT after firstline treatment had better outcomes than relapsed/refractory DLBCL patients(3-year PFS, P<0.001; 3-year OS,P<0.001). In the relapsed/refractory patients, pre-and post-HSCT PET findings were also associated with 3-year PFS(P=0.003 vs. P<0.001) and OS(P=0.027 vs. P<0.001). A significant correlation was observed between clinical response to chemotherapy before auto-HSCT and outcomes of patients in the entire cohort(3-year PFS, P<0.001;3-year OS, P<0.001) and in the subgroup of 21 patients with positive pre-HSCT PET(3-year PFS, P=0.084; 3-year OS, P=0.240). A significant association between survival and post-HSCT PET findings was observed in multivariate analysis(HR=5.168, P<0.001).Conclusions: PET results before and after HSCT are useful prognostic factors for DLBCL patients receiving HSCT. Patients who responded to chemotherapy, even those with positive pre-HSCT PET, are appropriate candidates for auto-HSCT.

Day 100 Absolute Monocyte/Lymphocyte Prognostic Score and Survival Post Autologous Peripheral Blood Hematopoietic Stem Cell Transplantation in Diffuse Large B-Cell Lymphoma

Day 100 prognostic factors post-autologous peripheral blood hematopoietic stem cell transplantation (APBHSCT) to predict clinical outcomes in diffuse large B-cell lymphoma (DLBCL) patients have not been studied. Thus, we retrospectively examined if day 100 absolute monocyte/lymphocyte prognostic score (AMLPS-100) affects clinical outcomes by landmark analysis from day 100 post-APBHSCT in DLBCL. Only DLBCL patients in complete remission at day 100 post-APBHSCT were evaluated. From 2000 to 2007, 134 consecutive DLBCL patients are qualified for the study. Patients with a day 100 absolute monocyte count (AMC-100) ≥ 630 cells/μL and day 100 absolute lymphocyte count (ALC-100) ≤ 1000 cells/μL experienced inferior overall survival (OS) and progression free survival (PFS). On multivariate analysis, the AMC-100 and ALC-100 remained independent predictors of OS and PFS. Combining both values into the AMLPS-100, the 5-year OS rates for low, intermediate, and high AMLPS-100 risk groups were 94% (95% CI, 83.0% - 98.1%), 70% (95% CI, 58.6% - 80.1%), and 13% (95% CI, 3.4% - 40.5%), respectively;and the 5-year PFS rates were 87% (95% CI, 74.0% - 94.1%), 68% (95% CI, 56.0% - 77.8%), and 13% (95% CI, 3.4% - 40.5%), respectively. The AMLPS-100 is a simple biomarker score that can stratify clinical outcomes from day 100 post-APBHSCT in DLBCL patients.

Potential for a pluripotent adult stem cell treatment for acute radiation sickness

Accidental radiation exposure and the threat of deliberate radiation exposure have been in the news and are a public health concern. Experience with acute radiation sickness has been gathered from atomic blast survivors of Hiroshima and Nagasaki and from civilian nuclear accidents as well as experience gained during the development of radiation therapy for cancer. This paper reviews the medical treatment reports relevant to acute radiation sickness among the survivors of atomic weapons at Hiroshima and Nagasaki, among the victims of Chernobyl, and the two cases described so far from the Fukushima Dai-Ichi disaster. The data supporting the use of hematopoietic stem cell transplantation and the new efforts to expand stem cell populations ex vivo for infusion to treat bone marrow failure are reviewed. Hematopoietic stem cells derived from bone marrow or blood have a broad ability to repair and replace radiation induced damaged blood and immune cell production and may promote blood vessel formation and tissue repair. Additionally, a constituent of bone marrow-derived, adult pluripotent stem cells, very small embryonic like stem cells, are highly resistant to ioniz-ing radiation and appear capable of regenerating radiation damaged tissue including skin, gut and lung.

Hepatic veno-occlusive disease after hematopoietic stem cell transplantation: Prophylaxis and treatment controversies

Hepatic veno-occlusive disease(VOD), also known as sinusoidal obstruction syndrome, is a major complication of hematopoietic stem cell transplantation and it carries a high mortality. Prophylaxis for hepatic VOD is commonly given to transplant recipients from the start of conditioning through the early weeks of transplant. However, high quality evidence from randomized controlled trials is scarce with small sample sizes and the trials yielded conflicting results. Although various treatment options for hepatic VOD are available, most have not undergone stringent evaluation with randomized controlled trial and therefore it remains uncertain which treatment offers real benefit. It remains controversial whether VOD prophylaxis should be given, which prophylactic therapy should be given, who should receive prophylaxis, and what treatment should be offered once VOD is established.

Higher plasma bilirubin predicts veno-occlusive disease in early childhood undergoing hematopoietic stem cell transplantation with cyclosporine

AIM: To analyze the association between plasma bilirubin levels and veno-occlusive disease(VOD) in non-adult patients undergoing hematopoietic stem cell transplantation(HSCT) during cyclosporine therapy.METHODS: A total of 123 patients taking cyclosporinewere evaluated using an electronic medical system at the Seoul National University Children's Hospital from the years 2004 through 2011. Patients were grouped by age and analyzed for incidence and type of adverse drug reactions(ADRs) including VOD. RESULTS: The HSCT patients were divided into three age groups: G#1 ≥ 18; 9 ≤ G#2 ≤ 17; and G#3 ≤ 8 years of age). The majority of transplant donor types were cord blood transplantations. Most prevalent ADRs represented acute graft-vs-host disease(a GVHD) and VOD. Although the incidences of a GVHD did not vary among the groups, the higher frequency ratios of VOD in G#3 suggested that an age of 8 or younger is a risk factor for developing VOD in HSCT patients. After cyclosporine therapy, the trough plasma concentrations of cyclosporine were lower in G#3 than in G#1, indicative of its increased clearance. Moreover, in G#3 only, a maximal total bilirubin level(BILmax) of ≥ 1.4 mg/d L correlated with VOD incidence after cyclosporine therapy. CONCLUSION: HSCT patients 8 years of age or younger are more at risk for developing VOD, diagnosed as hyperbilirubinemia, tender hepatomegaly, and ascites/weight gain after cyclosporine therapy, which may be represented by a criterion of plasma BILmax being ≥ 1.4 mg/d L, suggestive of more sensitive VOD indication in this age group.

Local Cutaneous Effects Associated with Chlorhexidine-Impregnated Gel Dressing in Hematopoietic Stem Cell Transplantation Patients

Introduction: Hematopoietic stem cell transplantation (HSCT) often requires a central venous catheter (CVC) for quick and safe vascular access. Currently, new technologies are available to protect the catheter insertion site, such as chlorhexidine-impregnated gel dressings (CIGD). Objectives: To evaluate local cutaneous effects associated with CIGD in patients undergoing HSCT. Methods: In this cross-sectional, prospective study, we evaluated 25 HSCT patients who had a CVC inserted. Patients were visited daily to monitor the CIGD changing procedures and evaluate abnormalities of the underlying skin after dressing removal. Findings: Local erythema was the most frequently detected abnormality, although usually transient and considered secondary to the mechanical trauma of dressing removal. The most severe lesions, consisting of areas of skin loss, erythematous plaques and/or vesicles were classified as skin irritation and presented in 11 (44%) of the 25 patients. An association test showed that skin irritation was more frequent in patients who underwent allogeneic HSCT (p = 0.03). Skin irritation was most frequently observed in areas of contact with the non-woven polyester adhesive tape (n = 22;88%), which made up the adhesive margins of the dressing. The CIGD was discontinued in 6 (54%) of the 11 patients who presented severe skin injuries. Conclusion: In this study, we detected that skin irritation was more frequent in patients who underwent allogeneic HSCT. The most common skin manifestation was skin loss.

Review of allogeneic hematopoietic stem cell transplantation with reduced intensity conditioning in solid tumors excluding breast cancer

Solid tumors in adults constitute a heterogeneous group of malignancy originating from various organ systems. Solid tumors are not completely curable by chemotherapy, even though some subgroups are very chemo-sensitive. Recently, oncologists have focused on the use of allogeneic hematopoietic stem cell transplantation(alloHSCT) with reduced intensity conditioning(RIC) for the treatment of some refractory solid tumors. After the demonstration of allogeneic graft-versus-leukemia effect in patients with hematological malignancies who received allo-HSCT, investigators evaluated this effect in patients with refractory metastatic solid tumors. According to data from experimental animal models and preliminary clinical trials, a graft-versus-tumor(GvT) effect may also be observed in the treatment of some solid tumors(e.g., renal cell cancer, colorectal cancer, etc.) after allo-HSCT with RIC. The use of RIC regimens offers an opportunity of achieving full-donor engraftment with GvT effect, as well as, a reduced transplant-related mortality. Current literature suggests that allo-HSCT with RIC might become a choice for elderly and medically fragile patients with refractory metastatic solid tumors.

Rapid identification of the origin of hematopoietic cells after allogeneic hematopoietic stem cell transplantation for leukemia with DNA-fingerprinting

In order to rapidly identify the presence of hematopoietic reconstruction after allogeneic hematopoietic stem cell transplantation (AHCT) for leukemia, we developed a technique for amplifying human hypervariable minisatellite DNA by polymerase chain reaction (PCR) combined with digoxigenin-labeled locus-specific oligonucleotide hybridization. DNA fingerprinting by this technique was used as a specific genetic marker to determine the success rate of engraftment after AHCT in 7 patients with leukemia. Six of them gained evidence of engraftment. The results show that the minisatellite DNA fingerprinting is of high individual specificity and is valuable in confirming engraftment after AHCT, especially when the patient and the donor are HLA identical and of the same sex, and have the same ABO-Rh blood grouping. The advantages of this technique are that there is no contamination by radioisotopes, and its use is not restricted by the half ulife. It is simple and highly sensitive. Engraftment of donor’s hematopoietic cells can be determined as early as 15 d post-transplantation using 100 ng DNA of the patient. We conclude that this technique is highly specific and sensitive, and can rapidly provide in formation about the origin of the hematopoietic cells, thus being of value in guiding early therapeutic intervention in AHCT.

Graft vs host disease impacts overall survival post allogeneic hematopoietic stem cell transplantation for acute lymphoblastic leukemia/lymphoma

AIM To examine the outcome and prognostic factors for high risk patients with acute lymphoblastic leukemia/lymphoma(ALL/LBL) who underwent allogeneic hematopoietic stem cell transplantation(HCT) at our center during the period of2010-2017 METHODS After due institutional review board approval, patients with high risk ALL/LBL post HCT were identified and included. All records were retrospectively collected. Time to event analysis was calculated from the date of HCT until event of interest or last follow up with Kaplan-Meir means. Cox regression model was used for multivariable analysis calculation.RESULTS A total of 69 patients were enrolled and examined with a median age of 21(14-61). After a median follow up of 15 mo(2-87.3), the 2-year cumulative incidence of relapse, cumulative incidence of non-relapse mortality, progression free survival and overall survival(OS) were 34.1%, 10.9%, 54.9% and 62.8%,respectively. In a multivariable analysis for OS; acute graft vs host disease(GVHD) and chronic GVHD were significant with corresponding hazard ratio 4.9(1.99-12; P = 0.0007) and 0.29(0.1-0.67; P = 0.0044), respectively.CONCLUSION Allogeneic-HCT for high risk ALL/LBL resulted in promising remissions particularly for patients with cGVHD.

Hematopoietic stem cell transplantation of aplastic anemia by relative with mutations and normal telomere length: A case report

BACKGROUND Immunosuppressive therapy and matched sibling donor hematopoietic stem cell transplantation(MSD-HSCT)are the preferred treatments for aplastic anemia(AA).CASE SUMMARY In this report,we describe a 43-year-old male patient with severe AA who carried BRIP1(also known as FANCJ),TINF2,and TCIRG1 mutations.Screening of the family pedigree revealed the same TINF2 mutation in his mother and older brother,with his older brother also carrying the BRIP1 variant and demonstrating normal telomere length and hematopoietic function.The patient was successfully treated with oral cyclosporine A,eltrombopag,and acetylcysteine,achieving remission 4 years after receiving MSD-HSCT from his older brother.CONCLUSION This case provides a valuable clinical reference for individuals with suspected pathogenic gene mutations,normal telomere length,and hematopoietic function,highlighting them as potential donors for patients with AA.

Considerations for hematopoietic stem cell transplantation in primary immunodeficiency disorders

Primary immunodeficiency disorders (PIDs) result from inborn errors in immunity.Susceptibility to infections and oftentimes severe autoimmunity pose life-threatening risks to patients with these disorders.Hematopoietic cell transplant (HCT) remains the only curative option for many.Severe combined immunodeficiency disorders (SCID) most commonly present at the time of birth and typically require emergent HCT in the first few weeks of life.HCT poses an unusual challenge for PIDs.Donor source and conditioning regimen often impact the outcome of immune reconstitution after HCT in PIDs.The use of matched or unmatched, as well as related versus unrelated donor has resulted in variable outcomes for different subsets of PIDs.Additionally, there is significant variability in the success of engraftment even for a single patient’s lymphocyte subpopulations.While certain cell lines do well without a conditioning regimen, others will not reconstitute unless conditioning is used.The decision to proceed with a conditioning regimen in an already immunocompromised host is further complicated by the fact that alkylating agents should be avoided in radiosensitive PIDs.This manuscript reviews some of the unique elements of HCT in PIDs and evidence-based approaches to transplant in patients with these rare and challenging disorders.

Clinical Utility of Molecular Diagnosis of Blood Stream Infections in Allogeneic Hematopoietic Stem Cell Transplantation Recipients with Hematologic Malignancies

Blood stream infections (BSIs) are a serious problem in patients with hematologic malignancies receiving allogeneic hematopoietic stem cell transplantation (ASCT). We evaluated the clinical utility of molecular diagnosis for the management of BSIs in such patients. We prospectively performed a polymerase chain reaction (PCR) analysis of microbial DNA in blood samples from 10 consecutive patients with hematological malignancies at least once a week for one month after ASCT. In total, 51 and 54 samples were analyzed by bacterial and fungal PCR assays, respectively. Bacteria were detected in 24 samples from 8 patients by PCR, but in only 2 samples from one patient by blood culture. Notably, the bacteria detected in at least half of the 24 samples were considered to have originated from the oral cavity. Fungi were detected in 5 samples from 3 patients by PCR, but not by blood culture. Most cases with positive PCR results were manageable with empirical antimicrobial therapy without disclosure of DNA data. Our DNA analyses did not directly contribute to management of BSIs, but did provide valuable microbiological evidence for the patients. Additionally, oral management appears to require a critical re-evaluation to reduce the occurrence of BSIs in ASCT recipients.

Advantageous tactics with certain probiotics for the treatment of graft-versus-host-disease after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation(HSCT)becomes a standard form of cellular therapy for patients with malignant diseases.HSCT is the first-choice of immunotherapy,although HSCT can be associated with many complications such as graft-versus-host disease(GVHD)which is a major cause of morbidity and mortality after allogeneic HSCT.It has been shown that certain gut microbiota could exert protective and/or regenerative immunomodulatory effects by the production of short-chain fatty acids(SCFAs)such as butyrate in the experimental models of GVHD after allogeneic HSCT.Loss of gut commensal bacteria which can produce SCFAs may worsen dysbiosis,increasing the risk of GVHD.Expression of G-protein coupled receptors such as GPR41 seems to be upre-gulated in the presence of commensal bacteria,which might be associated with the biology of regulatory T cells(Tregs).Treg cells are a suppressive subset of CD4 positive T lymphocytes implicated in the prevention of GVHD after allogeneic HSCT.Here,we discuss the current findings of the relationship between the modification of gut microbiota and the GVHD-related immunity,which suggested that tactics with certain probiotics for the beneficial symbiosis in gut-immune axis might lead to the elevation of safety in the allogeneic HSCT.

Hematopoietic stem cell transplantation for non-malignant gastrointestinal diseases

Both, autologous and allogeneic hematopoietic stem cell transplantation (HSCT) can be used to cure or ameliorate a variety of malignant and non-malignant diseases. The rationale behind this strategy is based on the concept of immunoablation using high-dose chemotherapy, with subsequent regeneration of naive T-lymphocytes derived from reinfused hematopoietic progenitor cells. In addition, the use of HSCT allows for the administration of high-dose chemotherapy (whether or not combined with immunomodulating agents such as antithymocyte globulin) resulting in a prompt remission in therapy-refractory patients. This review gives an update of the major areas of successful uses of HSCT in non-malignant gastrointestinal disorders. A Medline search has been conducted and all relevant published data were analyzed. HSCT has been proved successful in treating refractory Crohn&#x02019;s disease (CD). Patients with refractory celiac disease type II and a high risk of developing enteropathy associated T-cell lymphoma have shown promising improvement. Data concerning HSCT and mesenchymal SCT in end-stage chronic liver diseases are encouraging. In refractory autoimmune gastrointestinal diseases high-dose chemotherapy followed by HSCT seems feasible and safe and might result in long-term improvement of disease activity. Mesenchymal SCT for a selected group of CD is promising and may represent a significant therapeutic alternative in treating fistulas in CD.

Sarcopenia and gut microbiota alterations in patients with hematological diseases before and after hematopoietic stem cell transplantation

Objective: The aim of this study was to investigate the prevalence of sarcopenia(SP) and its relationship with gut microbiota alterations in patients with hematological diseases before and after hematopoietic stem cell transplantation(HSCT).Methods: A total of 108 patients with various hematological disorders were selected from Peking University People’s Hospital. SP was screened and diagnosed based on the 2019 Asian Sarcopenia Diagnosis Strategy. Physical measurements and fecal samples were collected, and 16S rRNA gene sequencing was conducted. Alpha and beta diversity analyses were performed to evaluate gut microbiota composition and diversity.Results: After HSCT, significant decreases in calf circumference and body mass index(BMI) were observed,accompanied by a decline in physical function. Gut microbiota analyses revealed significant differences in the relative abundance of Enterococcus, Bacteroides, Blautia and Dorea species before and after HSCT(P<0.05). Before HSCT, sarcopenic patients had lower Dorea levels and higher Phascolarctobacterium levels than non-sarcopenia patients(P<0.01). After HSCT, no significant differences in species abundance were observed. Alpha diversity analysis showed significant differences in species diversity among the groups, with the highest diversity in the postHSCT 90-day group and the lowest in the post-HSCT 30-day group. Beta diversity analysis revealed significant differences in species composition between pre-and post-HSCT time points but not between SP groups. Linear discriminant analysis effect size(LEfSe) identified Alistipes, Rikenellaceae, Alistipes putredinis, Prevotellaceae defectiva and Blautia coccoides as biomarkers for the pre-HSCT sarcopenia group. Functional predictions showed significant differences in anaerobic, biofilm-forming and oxidative stress-tolerant functions among the groups(P<0.05).Conclusions: This study demonstrated a significant decline in physical function after HSCT and identified potential gut microbiota biomarkers and functional alterations associated with SP in patients with hematological disorders. Further research is needed to explore the underlying mechanisms and potential therapeutic targets.

Hematopoietic stem cells in research and clinical applications:The“CD34 issue”

In this paper,experimental findings concerning the kinetics of hematopoietic reconstitution are compared to corresponding clinical data.Although not clearly apparent,the transplantation practice seems to confirm the basic proposals of experimental hematology concerning hematopoietic reconstitution resulting from successive waves of repopulation stemming from different subpopulations of progenitor and stem cells.One of the "f irst rate" parameters in clinical transplantations in hematology;i.e.the CD34+ positive cell dose,has been discussed with respect to the functional heterogeneity and variability of cell populations endowed by expression of CD34.This parameter is useful only if the relative proportion of stem and progenitor cells in the CD34+ cell population is more or less maintained in a series of patients or donors.This proportion could vary with respect to the source,pathology,treatment,processing procedure,the graft ex vivo treatment and so on.Therefore,a universal dose of CD34+ cells cannot be def ined.In addition,to avoid further confusion,the CD34+ cells should not be named "stem cells" or "progenitor cells" since these denominations only concern functionally characterized cell entities.