Benzylpenicillin plus an aminoglycoside versus meropenem in neutropenic lymphoma and leukaemia patients with a suspected bacterial infection: a randomized, controlled trial.

OBJECTIVES: In Norway, initial treatment of febrile neutropenia (FN) has traditionally been benzylpenicillin plus an aminoglycoside. Internationally, FN is often treated with a broad-spectrum ß-lactam antibiotic. We aimed to compare these two regimens in a prospective, randomized, trial in patients with lymphoma or leukaemia with an expected period of neutropenia ≥7 days, and a suspected bacterial infection. METHODS: Adult neutropenic patients with lymphoma or leukaemia, and a suspected bacterial infection, were randomized for treatment with benzylpenicillin plus an aminoglycoside or meropenem. The primary endpoint was clinical success, defined as no modification of antibiotics and clinical stability 72 h after randomization. RESULTS: Among 322 randomized patients, 297 proved evaluable for analyses. Fifty-nine per cent (95% CI 51%-66%), (87/148) of the patients given benzylpenicillin plus an aminoglycoside were clinically stable, and had no antibiotic modifications 72 h after randomization, compared with 82% (95% CI 75%-87%), (122/149) of the patients given meropenem (p <0.001). When the antibiotic therapy was stopped, 24% (95% CI 18%-32%), (36/148) of the patients given benzylpenicillin plus an aminoglycoside, compared with 52% (95% CI 44%-60%), (78/149) of the patients given meropenem, had no modifications of their regimens (p <0.001). In the benzylpenicillin plus an aminoglycoside arm, the all-cause fatality within 30 days of randomization was 3.4% (95% CI 1.2%-7.9%), (5/148) of the patients, compared with 0% (95% CI 0.0%-3.0%), (0/149) of the patients in the meropenem arm (p 0.03). CONCLUSION: Clinical success was more common in FN patients randomized to meropenem compared with the patients randomized to benzylpenicillin plus an aminoglycoside. The all-cause fatality was higher among the patients given benzylpenicillin plus an aminoglycoside.

Lung transplantation for bronchiolitis obliterans syndrome after allo-SCT.

Chronic GVHD (cGVHD) associated bronchiolitis obliterans syndrome (BOS) is a serious complication after allo-SCT, and lung transplantation (LTx) may be the ultimate treatment option. To evaluate this treatment, data on all patients with LTx after allo-SCT ever performed in Sweden, Norway, Denmark and Finland were recorded and compared with survival data from the Scandiatransplant registry. In total, LTx after allo-SCT had been performed in 13 patients. Allo-SCT was done because of AML (n=6), CML (n=3), ALL (n=2), immunodeficiency (n=1) and aplastic anemia (n=1). All developed clinical cGVHD, with median interval from allo-SCT to LTx of 8.2 (0.7-16) years. Median age at LTx was 34 (16-55) years, and the median postoperative observation time was 4.2 (0.1-15) years. Two patients died, one due to septicemia, the other of relapsing leukemia, after 2 and 14 months, respectively. Four developed BOS, one of these was retransplanted. The survival did not significantly differ from the survival in matched LTx controls, being 90% 1 year and 75% 5 years after LTx compared with 85% and 68% in the controls. We therefore suggest that LTx may be considered in carefully selected patients with BOS due to cGVHD after allo-SCT.

Ultra-short course sirolimus contributes to effective GVHD prophylaxis after reduced-intensity allogeneic hematopoietic cell transplantation.

Reduced-intensity conditioning (RIC) allo-SCT is a potentially curative treatment approach for patients with relapsed Hodgkin's or non-Hodgkin's lymphoma. In the present study, 37 patients underwent RIC allo-SCT after induction treatment with EPOCH-F(R) using a novel form of dual-agent immunosuppression for GVHD prophylaxis with CsA and sirolimus. With a median follow-up of 28 months among survivors, the probability for OS at 3 and 5 years was 56%. Treatment-related mortality was 16% at day +100 and 30% after 1 year of transplant. Acute GVHD grades II-IV developed in 38% of patients, suggesting that the regimen consisting of CsA and an ultra-short course of sirolimus is effective in the prevention of acute GVHD.

Bone marrow or peripheral blood stem cell transplantation from unrelated donors in adult patients with acute myeloid leukaemia, an Acute Leukaemia Working Party analysis in 2262 patients.

BACKGROUND: No survival benefit of using blood stem cells instead of bone marrow (BM) has been shown in matched unrelated donor (MUD) transplantation. DESIGN AND METHODS: In a retrospective registry analysis, we compared the use of blood stem cells (n = 1502) and BM (n = 760) from unrelated donors in patients aged 18-60 years with acute myeloid leukaemia (AML) undergoing myeloablative conditioning between 1997 and 2008. The blood stem cell recipients were older (P < 0.01), had more advanced disease (P < 0.0001) and received less total body irradiation (P < 0.0001) and more antithymocyte globulin (P = 0.01). RESULTS: Recovery of neutrophils and platelets was faster with blood stem cells (P < 0.0001). The incidence of acute graft-versus-host disease (GVHD) was similar, but there was more chronic GVHD in the blood stem cell group [hazard ratio (HR) = 1.29, P = 0.02]. There were no significant differences in nonrelapse mortality (NRM), relapse incidence and leukaemia-free survival (LFS) between the two groups amongst patients with AML in remission. In patients with advanced leukaemia, NRM was lower (HR = 0.61, P = 0.02) and LFS was prolonged (HR = 0.67, P = 0.002) when blood stem cells were used. At 3 years, LFS for all patients, regardless of remission status, was 41% for both treatment groups. The outcome was not affected after multivariable analysis adjusted for confounders. CONCLUSION: Blood stem cells compared with BM in MUD transplantation for patients with AML in remission resulted in the same rates of LFS. In patients with advanced leukaemia, the blood stem cell group had reduced NRM and improved LFS.

The outcome of allo-HSCT for 92 patients with myelofibrosis in the Nordic countries.

Between 1982 and 2009 a total of 92 patients with myelofibrosis (MF) in chronic phase underwent allo-SCT in nine Nordic transplant centers. Myeloablative conditioning (MAC) was given to 40 patients, and reduced intensity conditioning (RIC) was used in 52 patients. The mean age in the two groups at transplantation was 46±12 and 55±8 years, respectively (P<0.001). When adjustment for age differences was made, the survival of the patients treated with RIC was significantly better (P=0.003). Among the RIC patients, the survival was significantly (P=0.003) better for the patients with age <60 years (a 10-year survival close to 80%) than for the older patients. The type of stem cell donor did not significantly affect the survival. No significant difference was found in TRM at 100 days between the MAC- and the RIC-treated patients. The probability of survival at 5 years was 49% for the MAC-treated patients and 59% in the RIC group (P=0.125). Patients treated with RIC experienced significantly less aGVHD compared with patients treated with MAC (P<0.001). The OS at 5 years was 70, 59 and 41% for patients with Lille score 0, 1 and 2, respectively (P=0.038, when age adjustment was made). Twenty-one percent of the patients in the RIC group were given donor lymphocyte infusion because of incomplete donor chimerism, compared with none of the MAC-treated patients (P<0.002). Nine percent of the patients needed a second transplant because of graft failure, progressive disease or transformation to AML, with no significant difference between the groups. Our conclusions are (1) allo-SCT performed with RIC gives a better survival compared with MAC. (2) age over 60 years is strongly related to a worse outcome and (3) patients with higher Lille score had a shorter survival.

Hematopoietic stem cell transplantation in T-prolymphocytic leukemia: a retrospective study from the European Group for Blood and Marrow Transplantation and the Royal Marsden Consortium.

T-prolymphocytic leukemia (T-PLL) has a very poor prognosis with conventional immunochemotherapy. Incidental reports suggest that allogeneic hematopoietic stem cell transplantation (allo-HSCT) might have a role in this disease. Therefore, the purpose of the present study was to analyze the outcome of transplants for T-PLL registered with the European Group for Blood and Marrow Transplantation database and the Royal Marsden Consortium. Eligible were 41 patients with a median age of 51 (24-71) years; median time from diagnosis to treatment was 12 months, and in complete remission (CR) (11), partial remission (PR) (12), stable or progressive disease (13) and unknown in 5 patients. A total of 13 patients (31%) received reduced-intensity conditioning. Donors were HLA-identical siblings in 21 patients, matched unrelated donors in 20 patients. With a median follow-up of surviving patients of 36 months, 3-year relapse-free survival (RFS) and OS was 19% (95% CI, 6-31%) and 21% (95% CI, 7-34%), respectively. Multivariate analysis identified TBI and a short interval between diagnosis and HSCT as factors associated with favorable RFS. Three-year non relapse mortality and relapse incidence were each 41% with the majority of relapses occurring within the first year. These data indicate that allo-HSCT may provide effective disease control in selected patients with T-PLL.

Long-term follow-up of HCV-infected hematopoietic SCT patients and effects of antiviral therapy.

This prospective study was initiated in 1993 with the aim to study late effects and responses to antiviral therapy in a cohort of hepatitis C virus (HCV)-infected patients. A total of 195 patients were included from 12 centers. In all, 134 patients had undergone allogeneic and 61 autologous hematopoietic SCT (HSCT). The median follow-up from HSCT is currently 16.8 years and the maximum 27.2 years. Overall 33 of 195 patients have died of which 6 died from liver complications. The survival probability was 81.6% and the cumulative incidence for death in liver complications was 6.1% at 20 years after HSCT. The cumulative incidence of severe liver complications (death from liver failure, cirrhosis and liver transplantation) was 11.7% at 20 years after HSCT. In all, 85 patients have been treated with IFN; 42 in combination with ribavirin. The sustained response rate was 40%. The rates of severe side effects were comparable to other patient populations and no patient developed significant exacerbations of GVHD. Patients receiving antiviral therapy had a trend toward a decreased risk of severe liver complications (odds ratio=0.33; P=0.058). HCV infection is associated with morbidity and mortality in long-term survivors after HSCT. Antiviral therapy can be given safely and might reduce the risk for severe complications.

Clinical effect of buffy-coat vs. apheresis platelet concentrates in patients with severe thrombocytopenia after intensive chemotherapy.

BACKGROUND AND OBJECTIVES: Therapeutic or prophylactic use of platelet concentrates (PC) is essential for patients with thrombocytopenia due to intensive chemotherapy for various malignancies. PC quality has been improved after introduction of storage containers that are more oxygen permeable than the second-generation PC containers. Consequently, shelf life of PCs at our blood bank has been extended to 6.5 days after monitoring each PC for bacterial contamination. In this prospective observational study, we compared apheresis PCs harvested by Amicus cell separator with buffy-coat (BC) PCs during storage for up to 6.5 days. MATERIALS AND METHODS: All PCs were collected from healthy volunteer donors and were prepared for routine clinical use. A total of 446 transfusion episodes with 688 PCs for 77 adult patients with oncological and haematological diseases were registered during a 13-month period. Outcome measures were corrected count increment after 1 h (CCI-1), after 18-24 h (CCI-2), and transfusion intervals. Transfusions were carried out after storage from 1.5 to 6.5 days. RESULTS: Both CCI and the transfusion intervals decreased statistically significantly by increasing storage time after transfusions with apheresis PCs or BC PCs. However, less than 4% of the variation in CCI and transfusion interval could be explained by platelet storage time. There were no significant differences between BC PCs and apheresis PCs, regarding CCI and transfusion intervals. CONCLUSION: We can conclude that BC PCs are not inferior to apheresis PCs, and may serve the clinical purposes as well as apheresis PCs harvested by Amicus.

Cost of autologous peripheral blood stem cell transplantation: the Norwegian experience from a multicenter cost study.

High-dose therapy with autologous blood progenitor cell support is now routinely used for patients with certain malignant lymphomas and multiple myeloma. We performed a prospective cost analysis of the mobilization, harvesting and cryopreservation phases and the high-dose therapy with stem cell reinfusion and hospitalization phases. In total, 40 consecutive patients were studied at four different university hospitals between 1999 and 2001. Data on direct costs were obtained on a daily basis. Data on indirect costs were allocated to the specific patient based on estimates of relevant department costs (ie the service department's costs), and by means of predefined allocation keys. All cost data were calculated at 2001 prices. The mean total costs for the two phases were US$ 32,160 (range US$ 19,092-50,550). The mean total length of hospital stay for two phases was 31 days (range 27-37). A large part of the actual cost in the harvest phase was attributed to stem cell mobilization, including growth factors, harvesting and cryopreservation. In the high-dose chemotherapy phase, the most significant part of the costs was nursing staff. Average total costs were considerably higher than actual DRG-based reimbursement from the government, indicating that the treatment of these patients was heavily subsidized by the basic hospital grants.

Skin biopsies for early diagnosis and prognosis of graft-versus-host disease in recipients of allogeneic stem cells from blood or bone marrow.

A total of 61 patients with haematological malignancies were randomised either to allogeneic transplantation with blood stem cells (BSC) or bone marrow (BM), of whom 37 patients gave their consent to participate in a skin biopsy trial. Skin biopsies were performed before and after transplantation. The main objective was to assess whether biopsies of normal and affected skin from patients allografted with BSC showed a different histopathological and immunohistochemical pattern as compared to biopsies taken from patients allografted with BM. In addition, we wished to clarify whether sequential skin biopsies could be of prognostic value with regard to graft-versus-host disease (GVHD). Biopsies from normal or affected skin in BSC allografted did not disclose a different pattern as compared to BM transplants. Biopsies taken before the outbreak of acute and chronic GVHD showed no substantial differences between the groups. Irrespective of the type of allograft, the immunohistochemical picture of affected skin consistent with acute GVHD was dominated by a significantly higher number of T-lymphocytes (CD8+). Biopsies from normal skin before the outbreak of GVHD had no predictive value with regard to the development of acute or chronic GVHD. Immunohistochemistry is of supplementary help in distinguishing changes caused by cytotoxic agents from those caused by acute GVHD.

A prospective study of health-related quality of life, fatigue, anxiety and depression 3-5 years after stem cell transplantation.

Health-related quality of life (HRQOL), fatigue and psychological distress were prospectively assessed in 248 cancer patients treated with allogeneic (SCT, N=61), or autologous (ASCT, N=69) stem cell transplantation or conventional chemotherapy (CT, N=118) of whom 128 completed the assessments after 3 years. The European Organization for Treatment and Research of Cancer Core Quality of Life Questionnaire and the Hospital Anxiety and Depression Scale were administered nine (SCT/ASCT groups) or seven times (CT group) during the first year. The Fatigue Questionnaire was added at the final assessment. The SCT group displayed greater changes from baseline scores than the ASCT group, with more symptoms in the first months post transplant. A gradual improvement was found in both groups during the following 4-6 months, before stabilizing at baseline levels. Only minor changes were observed after the first year. All groups reported more fatigue than the population values after 3 years (P<0.01). The ASCT group also reported less optimal HRQOL (P<0.01-0.0001). No differences were found in anxiety and depression. Despite a faster recovery during the first months after transplant, the ASCT patients reported poorer functioning and more fatigue compared to the SCT group after 3 years. This suggests a need for a closer follow-up of these patients with special emphasis on functional status and fatigue.

Isolated HLA-C mismatches in unrelated donor transplantation for CML.

HLA-incompatibility is a major factor associated with outcome of allogeneic stem cell transplantation, but little is known on the impact of isolated HLA-C mismatches. We analyzed the outcome of 114 CML patients transplanted with marrow from unrelated donors of whom 24 were mismatched for HLA-C only (9/10 match). Univariate estimates of 5-year survival (SRV) (median follow-up: 47 months) in the HLA-matched group were 68+/-12 vs 42+/-20% (P=0.03) for the patients mismatched for HLA-C only and 33+/-33% in the mismatched group (non-HLA-C single mismatches and multiple mismatches) (P=0.0004). Disease stage, GVHD-prophylaxis (T-cell depletion), CMV-status and HLA-incompatibility were the risk factors associated (all P< or =0.005) with poor outcome. In the multivariate analysis, patients mismatched for loci other than HLA-C were at high risk of an adverse outcome (death: RR, 2.9; CI, 1.6-5.4, P=0.008, transplant-related mortality (TRM): RR, 3; CI, 1.5-5.9, P=0.0015). For patients mismatched for HLA-C only, the increased risk was of borderline significance (death: RR, 1.9; CI, 1-3.9, P=0.06, TRM: RR, 2.1; CI, 1-4.5, P=0.07). In spite of their lower expression, HLA-C antigens still represent relevant transplantation barriers that should be considered when searching for an unrelated donor.

Lung function 5 yrs after allogeneic bone marrow transplantation conditioned with busulphan and cyclophosphamide.

Long-term data on lung function after bone marrow transplantation (BMT) are inconclusive. Previously, a persistent reduction in gas transfer 1 yr after allogeneic BMT with busulphan and cyclophosphamide conditioning was reported by the current authors. In the present study this reduction was examined to see if it was permanent, transient or progressive. Prospectively, 43 consecutive adult patients with malignant blood disorders undertook lung function measurements prior to BMT, at 3 month intervals during the 1st yr after BMT and finally after 5 yrs. Mean baseline lung function values were >90% predicted. Within the 1st yr after BMT a transient decline in lung volumes and a persistent reduction in gas transfer were observed. After 5 yrs, baseline values were restored for all variables, except in four patients who developed obliterative bronchiolitis. Acute leukaemia and smoking were independently associated with gas transfer reductions at baseline and during the 1st yr after BMT. Allogeneic bone marrow transplantation with busulphan and cyclophosphamide conditioning was associated with a reduction in gas transfer 1 yr after bone marrow transplantation but baseline values were usually restored after 5 yrs. Since recovery may be gradual and slow, an observation period >1 yr is required before drawing conclusions concerning the development of a permanent reduction in lung function after allogeneic bone marrow transplantation conditioned with busulphan and cyclophosphamide.

Activated prothrombin complex concentrate (FEIBA) treatment during surgery in patients with inhibitors to FVIII/IX.

Non-activated and activated prothrombin complex concentrates (PCC/aPCC) have been used successfully to treat bleeds in haemophilia patients with inhibitors, but most physicians do not consider these products as effective as factor VIII/IX (FVIII/IX) concentrates in non-inhibitor patients. Thus, surgical procedures in inhibitor patients have been performed reluctantly. We have performed 14 minor and five major surgical and invasive diagnostic procedures in eight patients with congenital haemophilia A and inhibitors and in two patients with acquired haemophilia. When a loading dose of 100 U kg-1 of FEIBA was given followed by 200 U kg-1 day-1 in three divided doses every 8 h for 3 days, and then, when the daily dose was tapered to 100-150 U kg-1, no severe or unexpected bleeding complications were observed. However, one adverse event was observed. A 69-year-old man who suffered a myocardial infarction the third postoperative day following sigmoidectomy was managed safely with opiate analgesia, nitrates and diuretics, and the continued use of FEIBA(R).

Fewer relapses and increased chronic GVHD in patients transplanted with blood stem cells: a 5-year follow-up in a single centre study.

A total of 61 consecutive adult patients with haematological malignancies with an HLA-identical or one antigen-mismatched haploidentical family donor were randomised to allogeneic transplantation with blood stem cells (BSC) or bone marrow (BM). The median observation time was 5 years. Apart from engraftment parameters and acute graft-versus-host disease (GVHD), transplant-related mortality (TRM), incidence and severity of chronic GVHD, relapse, leukaemia-free survival (LFS) and overall survival (OS) were recorded. In the BSC and BM group, respectively, TRM was 8/30 and 4/30 (P=0.405), the incidence of chronic GVHD was 15/26 and 11/30 (P=0.138), extensive chronic GVHD was 10/26 and 4/30 (P=0.034), and relapse one and 10 patients (P=0.007). In log-rank test restricted to the cases allografted from HLA-identical donors, the difference remained significant with regard to relapse incidence (P=0.039), but not extensive chronic GVHD (P=0.072). No difference in LFS and OS was observed. In conclusion, our study strongly indicates an enhanced graft-versus-leukaemia effect in BSC recipients, which is not expressed in increased survival. The increased chronic GVHD in these patients may contribute, but the relation is complex and not yet understood.

Cost analysis of autologous peripheral blood stem cell transplantation for multiple myeloma.

High-dose chemotherapy (HDC) with autologous peripheral blood stem cell (PBSC) support is a common but expensive treatment for various hematological malignancies. A prospective cost analysis of evaluation/mobilization and the HDC + PBSC phase for patients with multiple myeloma was performed. Eleven consecutive patients at the National University Hospital Oslo, taking part in a Nordic treatment protocol, were included in the analysis during the period from May 1999 to December 2000. Clinical and resource use data were obtained prospectively on a daily basis registration and from patient records. The total cost for the evaluation/mobilization and the HDC + PBSC phase varied from 22,999 US dollars to 61,722 US dollars (mean 38,186 US dollars; median 30,569 US dollars). The mean length of hospital stay for the evaluation/mobilization phase was 8 days (range 4-17 days) and for the HDC + PBSC phase 19 days (range 14-29 days). A statistically significant correlation was found between the length of hospital stay and hospital costs for both phases (P < 0.003 and P < 0.010, respectively). A large part of the actual cost in the harvest phase was attributed to stem cell mobilization, including growth factors, harvesting and cryopreservation. In the HDC + PBSC phase, the most important part of the cost was paying nursing care personnel.

Donation of stem cells from blood or bone marrow: results of a randomised study of safety and complaints.

Biological consequences and physical complaints were compared for donors randomly assigned either to blood stem cell (BSC) or bone marrow (BM) donation. In the period 1994-1999, 61 consecutive donors were included. The BSC donors were given G-CSF 10 microg/kg s.c., daily during 5 days before the first leukapheresis. Nineteen donors had one leukapheresis, 10 required two and one donor needed three leukaphereses in order to reach the target cell number of 2 x 10(6) CD34(+) cells/kg bw of the recipient. A median platelet nadir of 102 x 10(9)/l was reached shortly after the last leukapheresis. Three weeks post harvest, 17 of 30 BSC donors had a mild leukopenia. Six had a leukopenia lasting more than a year before returning to normal values. Both groups were monitored prospectively through a standardised questionnaire completed by the donors. BSC donation was significantly less burdensome than BM donation and was preferred by the donors. The short-term risks of BSC mobilisation and harvest seem negligible. The potential long-term effects of G-CSF are unresolved and the donors must be followed closely.

[High dose therapy with autologous stem cell support--finally a progress in myelomatosis]. / Høydosebehandling med autolog stamcellestøtte--endelig et fremskritt ved myelomatose.

BACKGROUND: Since the introduction of the simple cyclic oral treatment with melphalan and prednisone in the late 1960s, there has been no substantial improvement in the therapy of multiple myeloma. In 1994, the Nordic Myeloma Study Group initiated a population-based, prospective study to evaluate the impact on survival of high dose chemotherapy in newly diagnosed, symptomatic patients under 60 years of age, compared to a conventionally treated control group. MATERIAL AND METHODS: 274 patients were treated according to a specified high dose protocol and compared to 274 patients from previous population-based trials fulfilling the same eligibility criteria. RESULTS: Median survival was 44 months in the control group and 62 months in the intensive treatment group (risk ratio 1.65; 95% CI = 1.28-2.14, P = 0.0001). A study of health-related quality of life (HRQoL) which was integrated in the trial showed a moderately reduced HRQoL associated with the intensive treatment phase, but no statistically significant difference beyond the first year of follow-up. In a cost-utility analysis of the trial, the cost per (quality-adjusted life years) was estimated at USD 26,000. INTERPRETATION: The incremental cost of the treatment is within what is usually thought to be acceptable limits. Further improvement of the results and reduction of stay in hospital would give an even more favourable cost-utility ratio.

Respiratory virus infections after stem cell transplantation: a prospective study from the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation.

Community-acquired respiratory virus infections are a cause of mortality after stem cell transplantation (SCT). A prospective study was performed at 37 centers to determine their frequency and importance. Additional cases were also collected to allow the analysis of risk factors for severe infection. Forty episodes were collected in the prospective study and 53 additional episodes through subsequent case collection. The frequency of documented respiratory virus infections was 3.5% among 819 allogeneic and 0.4% among 1154 autologous SCT patients transplanted during the study period. The frequency of lower respiratory tract infections (LRTI) was 2.1% among allogeneic and 0.2% among autologous SCT patients. The mortality within 28 days from diagnosis of a respiratory viral infection was 1.1% among allogeneic SCT while no autologous SCT patient died. The deaths of five patients (0.6%) were directly attributed to a respiratory virus infection (three RSV; two influenza A). On multivariate analysis, lymphocytopenia increased the risk for LRTI (P = 0.008). Lymphocytopenia was also a significant risk factor for LRTI in patients with RSV infections. The overall mortality in RSV infection was 30.4% and the direct RSV-associated mortality was 17.4%. For influenza A virus infection, the corresponding percentages were 23.0% and 15.3%. This prospective study supports the fact that community-acquired respiratory virus infections cause transplant-related mortality after SCT.