Worldwide Network for Blood and Marrow Transplantation (WBMT) recommendations for establishing a hematopoietic stem cell transplantation program in countries with limited resources (Part II): Clinical, technical and socio-economic considerations.

The development of hematopoietic stem cell transplantation (HSCT) programs can face significant challenges in most developing countries because such endeavors must compete with other government health care priorities, including the delivery of basic services. While this is may be a limiting factor, these countries should prioritize development of the needed expertise to offer state of the art treatments including transplantation, by providing financial, technological, legal, ethical and other needed support. This would prove beneficial in providing successful programs customized to the needs of their population, and potentially provide long-term cost-savings by circumventing the need for their citizens to seek care abroad. Costs of establishing HSCT program and the costs of the HSCT procedure itself can be substantial barriers in developing countries. Additionally, socioeconomic factors intrinsic to specific countries can influence access to HSCT, patient eligibility for HSCT and timely utilization of HSCT center capabilities. This report describes recommendations from the Worldwide Network for Blood and Marrow Transplantation (WBMT) for establishing HSCT programs with a specific focus on developing countries, and identifies challenges and opportunities for providing this specialized procedure in the resource constrained setting.

First report of pediatric hematopoietic stem cell transplantation activities in the eastern mediterranean region from 1984 to 2011: on behalf of the pediatric cancer working committee of the eastern mediterranean blood and marrow transplantation group.

To describe the hematopoietic stem cell transplantation (HSCT) activities for children in the Eastern Mediterranean (EM) region, data on transplants performed for children less than 18 years of age between 1984 and 2011 in eight EM countries (Egypt, Iran, Jordan, Lebanon, Oman, Pakistan, Saudi Arabia and Tunisia) were collected. A total of 5187 transplants were performed, of which 4513 (87%) were allogeneic and 674 (13%) were autologous. Overall, the indications for transplantation were malignant diseases in 1736 (38.5%) and non-malignant in 2777 (61.5%) patients. A myeloablative conditioning regimen was used in 88% of the allografts. Bone marrow (BM) was the most frequent source of stem cells (56.2%), although an increasing use of PBSC was observed in the last decade. The stem cell source of autologous HSCT has shifted over time from BM to PBSC, and 80.9% of autologous HSCTs were from PBSCs. The donors for allogeneic transplants were matched-related in 94.5% of the cases, and unrelated transplants, mainly cord blood (99%) in 239 (5.5%) cases. This is the first report to describe the pediatric HSCT activities in EM countries. Non-malignant disorders are the main indication for allogeneic transplantation. Frequency of alternate donor transplantation is low.

Peripheral blood stem cell mobilization in multiple myeloma comparison of two consecutive regimens in a limited resources country.

This study compared retrospectively the effectiveness, toxicity and hematopoietic recovery after autologous peripheral blood stem cell transplantation (ASCT) of two consecutive peripheral blood stem cell mobilization regimens in newly diagnosed MM patients. Patients in group 1 (n=178) were treated with 4 g/m2 of cyclophosphamide (CY) plus G-CSF (5 µg/kg/day). Patients in group 2 (n=117) with 750 mg/m2 of VP16 plus G-CSF (10 µg/kg/day). Optimal mobilization, defined by a target number of 8 × 106 CD34+ cells/kg collected, was achieved in 62.4% and 89.7% of patients in groups 1 and 2, respectively (P<10-4). The median number of aphaeresis sessions was reduced from two in group 1 to one in group 2 (P<10-4). Grade4 neutropenia, febrile neutropenia and IV antibiotic use were significantly more frequent in group 1 than in group 2 (P<10-4). Red blood cell transfusion requirements were significantly greater in group 1 (P=0.007). The switch to VP16-G-CSF10 resulted in a significant reduction of the number of hospitalization days (P<10-4). Neutrophil and platelet recovery after ASCT occurred on days 11 and 12, respectively, in the two groups with no significant differences. VP16+G-CSF10 allowed liberation of resources in the clinical and aphaeresis departments and demonstrated a better effectiveness-safety profile than CY+G-CSF5.

Reduced intensity conditioning is effective for hematopoietic SCT in dyskeratosis congenita-related BM failure.

BM failure (BMF) is a major and frequent complication of dyskeratosis congenita (DKC). Allogeneic hematopoietic SCT (allo-HSCT) represents the only curative treatment for BMF associated with this condition. Transplant-related morbidity/mortality is common especially after myeloablative conditioning regimens. Herein, we report nine cases of patients with DKC who received an allo-SCT at five different member centers within the Eastern Mediterranean Blood and Marrow Transplantation Registry. Between October 1992 and February 2011, nine DKC patients (male, 7 and female, 2), with a median age at transplantation of 19.1 (4.9-31.1) years, underwent an allo-HSCT from HLA-matched, morphologically normal-related donors (100%). Preparative regimens varied according to different centers, but was reduced intensity conditioning (RIC) in eight patients. Graft source was unstimulated BM in five cases (56%) and G-CSF-mobilized PBSCs in four (44%) cases. The median stem cell dose was 6.79 (2.06-12.4) × 10(6) cells/kg body weight. GVHD prophylaxis consisted of CsA in all nine cases; MTX or mycophenolate mofetil were added in five (56%) and two (22%) cases, respectively. Anti-thymocyte globulin was administered at various doses and scheduled in four (44%) cases. Median time-to-neutrophil engraftment was 21 (17-27) days. In one case, late graft failure was noted at 10.4 months post allo-HSCT. Only one patient developed grade II acute GVHD (11%). Extensive chronic GVHD was reported in one case, whereas limited chronic GVHD occurred in another four cases. At a median follow-up of 61 (0.8-212) months, seven (78%) patients were still alive and transfusion independent. One patient died of metastatic gastric adenocarcinoma and graft failure was the cause of death in another patient. This study suggests that RIC preparative regimens are successful in inducing hematopoietic cell engraftment in patients with BMF from DKC. Owing to the limited sample size, the use of registry data and heterogeneity of preparative as well as GVHD prophylaxis regimens reported in this series, we are unable to recommend a particular regimen to be considered as the standard for patients with this disease.

Allogeneic matched-sibling hematopoietic cell transplantation for AML: comparable outcomes between Eastern Mediterranean (EMBMT) and European (EBMT) centers.

Allogeneic hematopoietic cell transplantation (HCT) activity significantly increased in the Eastern Mediterranean area over the past decade. However, comparative outcomes with longer established centers, especially European Blood and Marrow Transplantation (EBMT) centers, have not been reported. We compared outcomes of matched-sibling allogeneic HCT between East Mediterranean Blood and Marrow Transplantation (EMBMT) and EBMT centers for adult patients with AML in first CR using myeloablative conditioning. We matched 431 patients from EMBMT with 431 patients from EBMT centers according to patient, disease and transplant characteristics. EMBMT recipients and donors were more likely to be CMV seropositive. There were no significant differences in the incidence of acute or chronic GVHD, or the 3-year cumulative incidence of non-relapse mortality (NRM) and relapse incidence (RI) between the two groups (NRM: EMBMT=16% vs EBMT=11), (RI: EMBMT=13% vs EBMT=19%). Notably, the 3-year leukemia-free survival (LFS) and OS were similar between the groups (LFS: EMBMT=70±2% vs EBMT=69±3%), (OS: EMBMT=74±2% vs EBMT=73±2%). Despite differences in socioeconomics, health resources and transplant experience, matched-sibling allogeneic HCT outcomes in emerging centers in the EMBMT region appear similar to EBMT centers.

[Significance and contribution to the diagnosis of multiple myeloma according to the IGF1-R gene expression profile]. / Profil d'expression du gène IGF1-R dans le myélome multiple: signification et apport au diagnostic.

Multiple myeloma (MM) is a still incurable adult's severe hematologic malignancy. It is characterized by deregulation of several cytokines and their receptors. Among these cytokines, Insulin growth factor 1 (IGF1) and its receptor (IGF1-R) are well documented as major factor of malignant plasma cells growth and survival in multiple myeloma. The objective of this study was to analyze the expression of IGF1-R in multiple myeloma at diagnosis in correlation with clinical and biological data. IGF1-R gene plasma cells expression was studied in 47 patients and 17 controls by Taqman technology RT-PCR. IGF1-R gene was down expressed in the malignant plasma cells of MM patients at diagnosis compared to normal plasma cells, isolated from healthy donors (p = 0.01). Expression decrease was accentuated in the disease advanced stage IIIB. A negative correlation was found between IGF1-R malignant plasma cells expression and the percentage of bone marrow invasion (p = 0.03). Bone marrow infiltration greater than 30% was significantly associated with a low level of IGF1-R gene expression (p = 0.04). Our results suggest that the decreased expression of IGF1-R by malignant plasma cells is a prognostic factor associated with severe disease. Understanding of mechanisms involved in IGF1-R expression negative regulation may contribute to the discovery of new targets therapy in myeloma. the discovery of new targets therapy in myeloma.

Association of stromal cell-derived factor-1-3'A polymorphism to higher mobilization of hematopoietic stem cells CD34+ in Tunisian population.

We explored the influence of polymorphisms in genes encoding the chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 in a cohort of Tunisian patients with malignant hematologic diseases multiple myeloma [MM], non-Hodgkin's lymphoma [NHL], Hodgkin's disease, and acute myeloid leukemia [AML], who underwent stem cell mobilization for autologous transplantation versus a group of healthy donors for allogeneic transplantation. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLp) analysis was used for rapid identification of genotypes. Significant associations for SDF1-3'A polymorphism were observed exclusively in patients with MM and NHL. While there was a lack of all association of SDF-1 polymorphism with AML patients. However, considering that the ability of mobilization varies among subjects, we have observed that the SDF1-3'A allele was associated with good mobilization capacity. Interestingly, the association was mainly observed among healthy allogeneic transplant donors where the analysis was not biased by background disease or chemotherapy (P=.010; odds ratio=2.603; confidence interval [95%]=1.239-5.466).

Monitorage de l'infection active a CMV par deux methodes : antigenemie PP65 et PCR qualitative sur plasma

Au cours de ce travail nous avons evalue deux methodes diagnostiques de l'infection active a CMV (antigenemie pp65 CMV et PCR qualitative) quant a leur utilite dans le monitorage de cette infection. Notre travail a porte sur 31 patients allogreffes de moelle osseuse dont 22 ont developpe une infection active a CMV. Le pourcentage des antigenemies positives etait de 59contre 28PCR positives. En mediane; les PCR se sont positivees 14 jours apres l'antigenemie. La duree de positivite de l'antigenemie etait de 5 semaines contre une semaine pour la PCR et la positivite de la PCR n'etait jamais isolee. Le taux de concordance de 61;5entre les deux techniques et le coefficient ( = 0.50) modere temoignerait d'un degre moyen de precision des resultats. La PCR sur plasma a presente une association plus importante avec la maladie a CMV (p= 0;014). La GVHD etait le seul facteur favorisant l'infection active a CMV (p=0;02). Cette derniere (p= 0;001) et la maladie a CMV (p= 0;04) ont presente des facteurs de mauvais pronostic chez nos patients. L'antigenemie constitue une methode de choix pour le diagnostic et le monitorage de l'infection active a CMV. Alors que la PCR qualitative sur plasma ne presente pas d'interet dans ce contexte

Allogeneic hematopoietic stem cell transplantation for acquired aplastic anemia using cyclophosphamide and antithymocyte globulin: a single center experience.

Between February 1998 and October 2007, 97 (69 male, 28 female) patients with acquired aplastic anemia and a median age of 18 years (range, 2-39) received related allogeneic hematopoietic stem cell transplantation. Ninety-five patients received bone marrow grafts and two patients G-CSF primed peripheral blood stem cell transplantation. The donors were genotypically HLA-identical siblings in 94 cases, HLA-matched parents in 2 cases and a syngeneic twin in 1 case. Median time from diagnosis to transplantation was 2 months (range, 1-15). Conditioning regimen consisted of cyclophosphamide combined with antithymocyte globulin in all patients. For graft versus host disease (GVHD) prophylaxis, all patients received methotrexate and cyclosporine. Eighty-six patients showed evidence of hematopoietic engraftment. Eight patients died before engraftment. Rejection rate was 14.8% with three primary graft failures and eight secondary graft rejections occurring between 2 and 27 months post transplantation. Of the 11 rejecting patients, 3 died from infection and 8 proceeded to a second transplantation. Among the eight patients re-transplanted, seven are alive with successful second engraftments and one died from acute grade III GVHD. Acute GVHD occurred in 15.5% and extensive chronic GVHD in only 5.3% of patients. The 4-year overall probability of survival was 76.8%. Infection was the cause of 81.1% of deaths. The major factor affecting survival was onset of infection before transplantation. Major ABO donor-recipient incompatibility, disease severity and acute GVHD had also negative impact on survival. These results could be improved by reducing the time to transplant and by a more efficient supportive care policy.Bone Marrow Transplantation advance online publication, 27 July 2009; doi:10.1038/bmt.2009.175.

Allogeneic hematopoietic stem cell transplantation in Tunisia.

In 1998, the Tunisian team of the 'Centre National de Greffe de Moelle Osseuse' initiated allogeneic hematopoietic SCT (AHSCT) in Tunisia. As of June 2007, information was collected about 299 patients with a first AHSCT and 12 additional retransplants. The median age was 19 years (range 2-49 years). The main indications were aplastic anemia (n=106, 36%), leukemia and nonmalignant disorders (n=153, 51%), Fanconi anemia (n=26, 9%) and other nonmalignant disorders (n=14, 4%). Preparative regimens depended on indication. All donors were HLA geno-identical. The stem cell sources were BM (87%) and PBSCs (13%). At the time of analysis, 200 patients (67%) were alive after a median follow-up of 42 months (range 3-112 months). The overall TRM rate was 17%. Outcome depended on indication. According to our results, allogeneic HSCT is potentially curative for hematological diseases, but it is a toxic approach for malignant disorders.

Analysis of cytomegalovirus (CMV) viremia using the pp65 antigenemia assay, the amplicor CMV test, and a semi-quantitative polymerase chain reaction test after allogeneic marrow transplantation.

A pp65 antigenemia assay for polymorphonuclear leukocytes (PMNLs) (CINAkit Rapid Antigenemia), and a qualitative polymerase chain reaction (PCR) test for plasma 'PCR-P qual' (Amplicor cytomegalovirus [CMV] test) were performed for 126 samples (blood and plasma) obtained from 18 bone marrow transplant patients, over a 9-month surveillance period. Among those samples, 92 were assayed with a semi-quantitative PCR test for PMNLs 'PCR-L quant.' The number of samples with a positive CMV test for antigenemia and PCR-P qual assays was 20.63% and 12.7%, respectively, whereas the PCR-L quant assay was positive in 48 of the 92 samples assayed (52.17%). The rates of concordance of the results of PCR-P qual and antigenemia, PCR-P qual and PCR-L quant, antigenemia and PCR-L quant were 92%, 65.2% and 66.8%, respectively. The analysis of the results for the 92 specimens tested by all 3 methods showed a rate of concordance of 63% among all methods. Good agreement (kappa=0.72) was found only between pp65 Ag and PCR-P qual assays. Clinical disease correlates with an antigenemia high viral load. Three patients had CMV disease despite preemptive therapy, and all of them had graft-versus-host-disease (GVHD). PMNLs-based assays are more efficient in monitoring CMV reactivation, but for high-risk patients with GVHD, more sensitive assays (real-time PCR) must be done.

[Prognosis value of the pp65 antigenemia and semi-quantitative PCR in the detection of the CMV reactivation in bone marrow grafted patients]. / Valeur pronostique de l'antigénémie pp65 et de la PCR semi-quantitative dans la détection de la réacti- vation du CMV chez les greffés de moelle osseuse.

In this article a Cytomegalovirus (CMV) antigenemia and semiquantitative PCR retrospective evaluation of 26 bone marrow allo-grafted patients for different haematological disease is reported. Eighteen patients had a CMV reactivation despite a prophylactic treatment, seven of those patients had both positive antigenemia pp65 and positive semi-quantitative CMV PCR. During CMV reactivation, 3 patients developed a CMV disease despite a pre-emptive therapy. The follow up of the antigenemia was performed since D21 until D100 post transplantation, the antigenemia positivity occurred at D53 and was preceded about 7 days by CMV PCR positivity The CMV disease wasn't associated with a high viral load. All patients that had CMV reactivation had a positive CMV serology before the graft, whereas only 37.5% of the patients who did not reactivate had a positive CMV serology. Respectively half patients who reactivated and only 12.5% of those who didn't had a Graft versus host disease (GVHD), witch preceded the reactivation about 21 days in six of the formers. Clinical and biological signs presented by our patients in this cases report, seems to be associated more with the GVHD than with CMV reactivation.

Detection of catheter-related bloodstream infections by the Gram stain-acridine orange leukocyte cytospin test in hematopoietic stem cell transplant recipients.

In patients with central venous catheters (CVCs), catheter-related bloodstream infections (CRBI) are a prominent cause of morbidity, excess hospital costs, and in some cases mortality. The aim of this prospective study was to assess the validity of the Gram stain-acridine orange leukocyte cytospin (AOLC) test for the diagnosis of CRBI in hematopoietic stem cell transplant (HSCT) recipients with nontunnelled CVCs, using the differential-time-to-positivity (DTP)/clinical criteria as the criterion standard to define CRBIs. CVCs were externalized, nontunnelled, polyurethane double lumen catheters (Arrows, Readings, USA). All CVCs were placed in the subclavian vein by the infraclavicular approach, in the operating room. Catheters were inserted percutaneously, using the Seldinger technique. Study catheters were not exchanged over guidewires. Between May 2002 and December 2004, a total of 245 consecutive patients were included. Twenty-six of the 245 patients (10.6%) had CRBI as determined by the DTP method. The Gram stain-AOLC was positive in only two patients (7.6%) with a CRBI. Our results suggest that the Gram stain-AOLC test is not useful for the diagnosis of catheter-related bloodstream infection in HSCT recipients.2006.

Prospective randomised comparison of the COBE spectra version 6 and haemonetics MCS(+) cell separators for hematopoietic progenitor cells leucapheresis in patients with multiple myeloma.

A randomised crossover trial of two separators was undertaken to compare the mononuclear cell, CD34(+) cell and CFU-GM yield, in patients (<61 years) with previously untreated symptomatic multiple myeloma. After first-line therapy, all patients received mobilising chemotherapy (cyclophosphamide 4 g/m(2)) and daily G-CSF. The first leucapheresis was performed on the first day the peripheral blood absolute CD34(+) cell count was > 20 cells/microl. All patients underwent 2 leucaphereses on consecutive days. The patients were randomised to undergo either the first or second leucapheresis using the COBE Spectra. The target duration of the procedure on the COBE Spectra was 2 total blood volumes, and for the Haemonetics MCS(+) it was 20 cycles with four recirculations. Between September 2003 and March 2005, 60 patients were entered in the study. COBE Spectra version 6 processed significantly larger volumes of blood than the Haemonetics MCS(+) (8,845 and 5,680 ml, respectively, P < 0.01). The absolute yield of mononuclear cells (2.1 vs. 1.5 x 10(8)/kg, P = 0.04), CFU-GM (11 vs. 3 x 10(4)/kg, P = 0.01) and CD34(+) cells (3 vs. 1.7 x 10(6)/kg, P = 0.02) were all significantly higher with the COBE Spectra version 6, as were the yields per unit volume of blood processed. In conclusion, our study shows that COBE Spectra Version 6 is faster and has a better yield than the Haemonetics MCS(+), in patients with multiple myeloma.

Bone marrow transplantation from matched related donors for patients with Fanconi anemia using low-dose busulfan and cyclophosphamide as conditioning.

Seventeen patients with Fanconi anemia (FA) underwent allogeneic bone marrow transplantation (BMT) from matched related donors (MRD) between January 1999 and June 2003. Median age at BMT was 11 years. Conditioning regimen consisted of low-dose cyclophosphamide (CY; 40 mg/kg) and busulfan (BU; 6 mg/kg) with the addition of lymphoglobulin (20 mg/kg) in two patients. Graft-versus-host disease (GVHD) prophylaxis included cyclosporine A (CsA) and methotrexate (MTX; 5 mg/m(2) at day 1, 3, 6). All patients engrafted (for an absolute neutrophil count >0.5 x 10(9)/L) after a median time of 12 days (range 10-16 days). Fourteen patients (82%) had sustained grafts, whereas three others (18%) rejected grafts between day +39 and +80 after transplantation. Two of them are still alive after successful second PBSC transplantation and one died. Acute and chronic GVHD occurred in 23% and 13% of patients, respectively. With a median follow-up of 16 months (range 3-53 months), survival rate was 72% and Karnofsky score was at least 90%. The low-dose BU/CY regimen, in FA patients allografted from an HLA-matched related donor, allowed engraftment with relative low toxicity. Early graft failure (GF) remains a problem and may require modification of this regimen.

Prevalence of inherited prothrombotic abnormalities and central venous catheter-related thrombosis in haematopoietic stem cell transplants recipients.

In this prospective study, we assessed the incidence of central venous catheter (CVC)-related thrombosis in haematopoietic stem cell transplant (HSCT) recipients. We determined the contribution of inherited prothrombotic abnormalities in blood coagulation to CVC-related thrombosis in these patients. The study was conducted between May 2002 and September 2004. CVCs were externalized, nontunneled, polyurethane double lumen catheters. Before catheter insertion, laboratory prothrombotic markers included factor V Leiden, the prothrombin gene Gly20210A mutation, plasma antithrombin levels, and protein C and S activity. All patients were systematically examined by ultrasonography just before, or <24 h after, catheter removal, and in case of clinical signs of thrombosis. A total of 171 patients were included during the 28-month study period. Five (2.9%) and three (1.7%) patients had evidence of protein C and protein S deficiency, respectively. Only one patient had an antithrombin deficiency (0.6%). In total, 10 patients (5.8%) were heterozygous for the factor V Leiden mutation, and one patient had heterozygous prothrombin G20210A mutation (0.6%). We observed a CVC-related thrombosis in 13 patients (7.6%). Thrombosis was diagnosed in four out of 20 patients (20%) with a inherited prothrombotic abnormality compared to nine of 151 patients (6%) who did not have a thrombophilic marker (relative risk 3.3 CI 95% 1.1-9.9). Our results suggest that inherited prothrombotic abnormalities contribute substantially to CVC-related thrombosis in HSCT recipients. In view of physicians' reluctance to prescribe prophylactic anticoagulant treatment in these patients, a priori determination of inherited prothrombotic abnormalities may form a basis to guide these treatment decisions.

First-line thalidomide-dexamethasone therapy in preparation for autologous stem cell transplantation in young patients (<61 years) with symptomatic multiple myeloma.

Thalidomide-dexamethasone therapy was given in patients (<61 years) with previously untreated symptomatic multiple myeloma. The aim of this study was to assess the efficacy and toxicity of this combination as first-line therapy, and to determine its effect on stem cell collection and engraftment. During first-line therapy, thalidomide and dexamethasone were administered for 75 days (200 mg/day) and 3 months, respectively. The monthly dose of dexamethasone was 20 mg/m2/day for 4 days, with cycles repeated on days 9 to 12 and 17 to 20 on the first and the third month of therapy. After first-line therapy, a collection of peripheral blood stem cells (PBSC) was performed. Between May 2003 and September 2004, 60 patients were included. On an intent-to-treat basis, the overall response (> or =partial response) rate was 74%, including 24% of patients who obtained a complete remission. Grade 3-4 toxicities consisted of infections (12%), deep-vein thrombosis (3%), constipation (5%), and neuropathy (5%). A total of 58 patients (96%) proceeded to PBSC mobilisation and yielded a median number of 8 x 10(6) CD34+ cells/kg. First-line thalidomide-dexamethasone therapy is effective and relatively well tolerated in young patients with symptomatic multiple myeloma. This combination does not affect PBSC mobilisation.

Difference in time to positivity is useful for the diagnosis of catheter-related bloodstream infection in hematopoietic stem cell transplant recipients.

Catheter-related bloodstream infections are associated with recognized morbidity and mortality. Accurate diagnosis of such infections results in proper management of patients and in reducing unnecessary removal of catheters. We carried out a prospective study in a bone marrow transplant unit to assess the validity of a test based on the earlier positivity of central venous blood cultures in comparison with peripheral blood cultures for predicting catheter-related bacteremia. Between May 2002 and June 2004, 38 bloodstream infections with positive simultaneous central venous catheter and peripheral vein blood cultures were included. A total of 22 patients had catheter-related bacteremias and 16 had noncatheter-related bacteremias, using the catheter-tip culture/clinical criteria as the criterion standard to define catheter-related bacteremia. Differential time to positivity of 120 min or more was associated with 86% sensitivity and 87% specificity. In conclusion, differential time to positivity of 120 min or more is sensitive and specific for catheter-related bacteremia in hematopoietic stem cell transplant recipients who have nontunnelled short-term catheters.