Infectious complications following allogeneic stem cell transplantation: reduced-intensity vs. myeloablative conditioning regimens

Comparison of Infectious Complications in Patients Receiving High-Dose Cyclophosphamide as GvHD Prophylaxis After Transplantation From A 9/10 HLA-Matched Unrelated Donor with Standard GvHD Prophylaxis After Transplant From A Fully Matched Related Donor

Background

The aim of this study was to evaluate whether cyclophosphamide administered after allogeneic stem cell transplantation (ASCT) from 9/10 HLA-Matched Unrelated Donors (MMUD) increases the rates of bacterial, fungal, viral infections, complications (hemorrhagic cystitis (HC)), and infection-related mortality compared to allogeneic stem cell transplantation from matched related donors (MRD).

Methods

This is a retrospective multicenter study. 45 MMUD ASCT patients who received posttransplant cyclophosphamide+methotrexate+calcineurin inhibitor compared with 45 MRD ASCT patients who received methotrexate+calcineurin inhibitor.

Results

Although there was a statistically significant prolongation of neutrophil engraftment time in the PTCy arm, there was no statistically significant difference in bacterial infection frequencies between the groups (PTCy; 9 (20%), control; 8 (17.8%), p=0.778). The distribution of CMV infection in the first 100 days was similar (p=0.827), but the distribution of CMV infection rate between the 100th and 365th days was observed more frequently in the control group (p=0.005). HC rates and their grades were similar in both groups (PTCy; 4 (8.8%), control; 6 (13.3%) p=0.502). The rates of VZV infection and invasive aspergillosis were similar in the PTCy and control groups (13.3% in the PTCy and 17.8% in the control group p=0.561). There is also no statistically significant difference in survival analysis (OS, LFS, GRFS, RI, IRM, NRM) between groups. However, the incidence of cGVHD was significantly higher in the control group (P=0.035).

Conclusions

The addition of PTCy to standard GvHD prophylaxis in MMUD ASCT does not lead to an increase in CMV reactivation, bacterial infections, invasive fungal infection, viral hemorrhagic cystitis, or mortality.

Cytomegalovirus Infection after Allogeneic Hematopoietic Cell Transplantation under 100-Day Letermovir Prophylaxis: A Real-World 1-Year Follow-Up Study

The prevention and management of cytomegalovirus (CMV) reactivation is important to improve the outcomes of allogeneic hematopoietic cell transplantation (allo-HCT) recipients. The aim of this study was to analyze real-world data regarding the incidence and characteristics of CMV infections until 1 year after allo-HCT under 100-day letermovir prophylaxis. A single-center retrospective study was conducted between November 2020 and October 2021. During the study period, 358 patients underwent allo-HCT, 306 of whom received letermovir prophylaxis. Cumulative incidence of clinically significant CMV infection (CS-CMVi) was 11.4%, 31.7%, and 36.9% at 14 weeks, 24 weeks, and 1 year post-HCT, respectively. Through multivariate analysis, the risk of CS-CMVi increased with graft-versus-host disease (GVHD) ≥ grade 2 (adjusted odds ratio 3.640 [2.036-6.510]; p < 0.001). One-year non-relapse mortality was significantly higher in letermovir breakthrough CS-CMVi patients than those with subclinical CMV reactivation who continued receiving letermovir (p = 0.002). There were 18 (15.9%) refractory CMV infection cases in this study population. In summary, letermovir prophylaxis is effective at preventing CS-CMVi until day 100, which increased after the cessation of letermovir. GVHD is still a significant risk factor in the era of letermovir prophylaxis. Further research is needed to establish individualized management strategies, especially in patients with significant GVHD or letermovir breakthrough CS-CMVi.

Infection-related mortality after HLA-identical and haploidentical hematopoietic cell transplantation using reduced-intensity conditioning in an outpatient setting

BACKGROUND

Despite the improvements in supportive care for allogeneic-hematopoietic cell transplantation (allo-HCT) recipients, infectious complications and infection-related mortality (IRM) continue to be a major issue for transplantation centers.

METHODS

We herein report the infectious complications and IRM of 107 and 89 patients that underwent haploidentical (haplo-HCT) or HLA-identical HCT at a tertiary referral center during 2013-2020. Patients in the haplo-HCT group received post-transplant cyclophosphamide (PT-Cy), and all received reduced-intensity conditioning regimens.

RESULTS

More haplo-HCT recipients presented severe infections in the pre-engraftment period (22.4% vs. 6.7%, p = 0.003). Viral (14.9% vs. 4.5%, p = 0.016) and fungal (12.1% vs. 1.1%, p = 0.003) etiologies were more common in this period in this group. The 100-day and 2-year cumulative incidence of IRM was 15% and 21% for the haplo-HCT and 5.6% and 17% for the HLA-identical group; no significant differences were observed between the groups. Fungal pathogens mainly contributed to IRM (33.3%). Infections were the most common cause of mortality (40/81, 49.4%). There were significant differences in donor/recipient CMV serostatus between transplant groups (0.002).

CONCLUSIONS

No differences in IRM were observed based on allo-HCT type, with more haplo-HCT patients suffering from severe infections in the pre-engraftment period. Studies to assess future prevention, diagnostic, and treatment strategies to reduce IRM are warranted.

The Use of Voriconazole as Primary Prophylaxis for Invasive Fungal Infections in Patients Undergoing Allogeneic Stem Cell Transplantation: A Single Center's Experience

Background: Invasive fungal infections (IFI) following allogeneic stem cell transplant (allo-HCT) are associated with high morbidity and mortality. Primary prophylaxis using voriconazole has been shown to decrease the incidence of IFI. Methods: We conducted a retrospective analysis at the Bone Marrow Transplant (BMT) unit of the American University of Beirut including 195 patients who underwent allo-HCT for hematological malignancies and received voriconazole as primary prophylaxis for IFI. The primary endpoints were based on the incidence of IFI at day 100 and day 180, and the secondary endpoint based on fungal-free survival. Results: For the study, 195 patients who underwent allo-HCT between January 2015 and March 2021 were included. The median age at transplant was 43 years. Of the patients, 63% were male, and the majority of patients were diagnosed with acute myeloid leukemia (AML) (60%). Voriconazole was given for a median of 90 days and was interrupted in 20 patients. The majority of IFI cases were probable invasive aspergillosis (8%). The incidence of IFI including proven, probable and possible IFI was 34%. The incidence of proven and probable IFI was 5% were 8%, respectively. The incidence of proven-probable (PP-IFI) was 5.1% at day 100 and 6.6% at day 180. The majority of PP-IFI cases were invasive aspergillosis (8%). A univariate analysis of patients, transplant characteristics and IFI showed a significant correlation between the type of donor, disease status before transplant, graft-versus-host disease prophylaxis used and incidence of IFI. Only disease status post-transplant showed a significant correlation with fungal-free survival in the multivariate analysis. Conclusion: Primary prophylaxis with voriconazole in allo-HCT is associated with a low incidence of IFI. More studies are required to compare various antifungal agents in this setting.

Clinical characteristics and viral load patterns in children with cytomegalovirus gastrointestinal disease after allogeneic hematopoietic stem cell transplantation

Cytomegalovirus (CMV) reactivation in allogeneic hematopoietic stem cell transplantation (allo-HSCT) causes significant morbidity and mortality. This study aimed to investigate the clinical characteristics of children diagnosed with CMV GI disease after allo-HSCT. This was a retrospective cohort study of patients <19 years old that underwent allo-HSCT during an 11-year period. Of the 756 patients, 55.5% (n = 420) experienced post-transplant CMV DNAemia, 2.9% (n = 22) were diagnosed with proven CMV GI diseases, and the highest incidence was found in familial mismatched donors (5.6%, P = 0.029). CMV GI disease was diagnosed <100 days of transplant in 68.2% (n = 15/22), and 13.6% (n = 3/22) did not have concurrent CMV DNAemia. Patients were divided into five groups based on the patterns of CMV viremia initiation and duration post-HSCT. At 3 months post-transplant, lower CD4+ (P = 0.006) and CD8+ (P = 0.011) T-cell counts were observed in patients with waxing and waning CMV viral load titers >100 days post-transplant (groups 1-3) compared to those with CMV DNAemia only prior to 100 days post-transplant and those without concurrent CMV DNAemia (groups 4-5). A higher 1-year all-cause mortality was observed in groups 1-3 compared to groups 4-5 (42.8% vs. 0%; P = 0.051). Active surveillance and aggressive management of CMV reactivation is crucial, especially in children with delayed CD4+ and CD8+ T-cell reconstitution after allo-HSCT.

Infectious complications in allogeneic hematopoietic cell transplant recipients: Review of transplant-related risk factors and current state of prophylaxis

Allogeneic hematopoietic cell transplantation is a complex procedure that carries a significant risk of complications. Infections are among the most common of them. Several direct factors such as neutropenia, hypogammaglobulinemia, lymphopenia, mucosal barrier injury, and graft-versus-host disease have been shown to be associated with increased infectious risk post-transplant. Apart from direct factors, there are also indirect transplant-related factors that are the primary trigger to the formers' development. The most important of them are type of preparative regimen, graft source, donor type, graft-versus-host disease prophylaxis, and graft manipulation techniques. In this review, an attempt has been made to summarize the role of the transplant-related factors in the development of infectious complications and provide evidence underlying the current concept of infectious disease prophylaxis in patients after allogeneic hematopoietic cell transplantation.

Patterns of infection and infectious-related mortality in patients receiving post-transplant high dose cyclophosphamide as graft-versus-host-disease prophylaxis: impact of HLA donor matching

Post-transplant cyclophosphamide (PTCy) has become a promising option after allo-SCT, but infections may be more common than in traditional protocols. We herein report 117 consecutive adults who received PTCy-based alloSCT in our hospital: HaploSCT (34%), MRD (19%), and VUD (47%), respectively. The 18-month incidence of severe bacterial, viral, and IFI was 56%, 69%, and 8.7%, without differences between donor type, except for CMV infection and viral hemorrhagic cystitis, which had a higher incidence in the haploSCT cohort (58% vs. 43% and 30% vs. 8% on day +90, p < 0.05). Late infections by conventional respiratory viruses were common in all groups [33/87 (38%)]. The 2-year survival was 72% and did not differ by donor type. IRM at day 30, day 100, and 18 months was 1.7%, 4.4%, and 12%, without differences by donor type (p = 0.7). The primary cause of IRM was bacterial infection (42%). Grade 2–4 acute GvHD was the only independent predictor of IRM. Donor type had no impact on IRM or on survival. In our study, severe infections were common in all donor types using PTCy, with higher rates of early post-engraftment CMV-I and viral HC in haploSCT recipients, although lethal infections were uncommon and similar in all donor types.

Increased overall and bacterial infections following myeloablative allogeneic HCT for patients with AML in CR1

Presumably, reduced-intensity/nonmyeloablative conditioning (RIC/NMA) for allogeneic hematopoietic cell transplantation (alloHCT) results in reduced infections compared with myeloablative conditioning (MAC) regimens; however, published evidence is limited. In this Center for International Blood and Marrow Transplant Research study, 1755 patients (aged ≥40 years) with acute myeloid leukemia in first complete remission were evaluated for infections occurring within 100 days after T-cell replete alloHCT. Patients receiving RIC/NMA (n = 777) compared with those receiving MAC (n = 978) were older and underwent transplantation more recently; however, the groups were similar regarding Karnofsky performance score, HCT-comorbidity index, and cytogenetic risk. One or more infections occurred in 1045 (59.5%) patients (MAC, 595 [61%]; RIC/NMA, 450 [58%]; P = .21) by day 100. The median time to initial infection after MAC conditioning occurred earlier (MAC, 15 days [range, <1-99 days]; RIC/NMA, 21 days [range, <1-100 days]; P < .001). Patients receiving MAC were more likely to experience at least 1 bacterial infection by day 100 (MAC, 46% [95% confidence interval (CI), 43-49]; RIC/NMA, 37% [95% CI, 34-41]; P = .0004), whereas at least a single viral infection was more prevalent in the RIC/NMA cohort (MAC, 34% [95% CI, 31-37]; RIC/NMA, 39% [95% CI, 36-42]; P = .046). MAC remained a risk factor for bacterial infections in multivariable analysis (relative risk, 1.44; 95% CI, 1.23-1.67; P < .0001). Moreover, the rate of any infection per patient-days at risk in the first 100 days (infection density) after alloHCT was greater for the MAC cohort (1.21; 95% CI, 1.11-1.32; P < .0001). RIC/NMA was associated with reduced infections, especially bacterial infections, in the first 100 days after alloHCT.

Splenomegaly May Increase the Risk of Rejection in Low-Risk Matched Related Donor Transplant for Thalassemia, This Risk Can Be Partially Overcome by Additional Immunosuppression during Conditioning

Severe thalassemia syndromes (ST) are highly curable by bone marrow transplant (BMT), but rejection may still occur. We retrospectively analyzed our fully matched related donor transplants to establish if isolated splenomegaly is an independent risk factor for rejection and if this risk can be reduced by modifying the conditioning protocol. In this study, we compared rejection rates between patients with and without splenomegaly in 189 consecutive low-risk ST transplants across 2 sequential conditioning regimens: regimen A (August 2013 to December 2016): busulfan (14 mg/kg oral, not adjusted to serum levels), cyclophosphamide (200 mg/kg), and anti-thymocyte globulin (ATG) (Genzyme (Sanofi, Paris, France) 4 mg/kg or Fresenius (Grafalon, Neovii Biotech GmbH, Gräfelfing Germany) 16 mg/kg on days -12 to -10), and regimen B: same backbone as regimen A except fludarabine total dose of 150 mg was added upfront and ATG dose was increased to 7 mg/kg in case of splenomegaly and/or sex-mismatched transplants (January 2017 to September 2018). Compared with regimen A, in regimen B, both overall rejection rates (RRs) (16% versus 6.5%, P = .023) and treatment-related mortality (TRM) (9.9% versus 2.8%, P = .038) improved significantly. By Cox regression analysis, the improvement in RR between the 2 protocols was particularly significant in patients with splenomegaly (RR 54.5% versus 6.5%, P = .00015; TRM 18.2% versus 6.5%, P = .25) (hazard ratio, 4.13; confidence interval, 1.61 to 10.6; P = .003). The increased risk of rejection related to splenomegaly can be overcome by adding fludarabine to the standard ATG-Busulfan- Cyclophosphamide (ATG-Bu-Cy) protocol without significantly increasing transplant-related morbidity and mortality or resorting to splenectomy pre-BMT.

Monocenter study on epidemiology, outcomes, and risk factors of infections in recipients of 166 allogeneic stem cell transplantations during 1 year

OBJECTIVES

During allogeneic hematopoietic stem cell transplantation (allo-SCT), infections significantly contribute to morbidity and mortality. A monocentric prospective analysis was performed to assess epidemiology, risk factors, and outcomes of infections during the peri-transplant period.

METHODS

Data were recorded prospectively using a predefined questionnaire.

RESULTS

In 2015, 163 consecutive patients, 37.4% female, median age 59 (range 18-79) years received 166 allo-SCT. Median duration of leukopenia <10⁹ /L was 14.5 days (range 4-43 days). Fever of unknown origin (FUO) occurred in 118/166 patients (71.1%). Severe sepsis developed in 95, and septic shock developed in 26 patients. Intensive diagnostic workup helped to identify causative microorganisms only in a small number of infectious courses. All but 13 patients needed antibiotic therapy, each according to the standard operating procedures of the department. Cumulative incidence of death by infection after 1 year was 16.6% (95% CI: 11.3-22.7). The only risk factor for FUO in neutropenia was duration of neutropenia </≥14 days (55.4% vs 85.5%, P < .001).

CONCLUSION

Results of an elaborate diagnostic workup of infections in the peri-transplant period are scarce. Attention to risk factors might help to identify patients at risk for severe infections.

Pre-engraftment infectious complications and patient outcomes after allogeneic hematopoietic cell transplantation: a single-center experience from Lebanon

BACKGROUND

Infectious complications are significant causes of morbidity and mortality after allogeneic hematopoietic cell transplantation (allo-HCT). They occur variably over different periods, with scant data reported from Lebanon and neighboring countries. In this study, we described the pre-engraftment neutropenic phase, febrile episodes, and peri-transplant medical complications in patients undergoing allo-HCT at a tertiary-care hospital.

METHODS

This is a retrospective chart review of patients who underwent allo-HCT between 2007 and 2016 at Makassed General Hospital in Beirut, Lebanon. Data were extracted from medical records, the HCT registry, and medical laboratory logbooks.

RESULTS

One hundred and six patients were included, 75% having hematologic malignancies and 13% aplastic anemia. None received antibacterial prophylaxis with fluoroquinolones. Yet from conditioning chemotherapy till the say before HCT, 32% of the patients received broad-spectrum antibiotics (BSA) due to fever or infection. At the day of cell infusion, 41.5% of the patients were on BSA. Neutrophil engraftment failure was recorded in 8% of the patients. The cumulative incidence of pre-engraftment bacteremia and Gram-negative bacteremia was 14.3 and 7.1%, respectively. Aplastic anemia was an independent risk factor for pre-engraftment bacteremia [hazard ratio (HR) = 3.86, 95% confidence interval (CI) (1.29-11.5), P = 0.02]. The cumulative incidence of pre-engraftment pneumonia was 11.2%. Patient age significantly increased the risk of pre-engraftment pneumonia [HR = 12.35, 95% CI (1.27-120.50), P = 0.03]. Six-month post-transplant mortality reached 17% in our cohort. Myelodysplastic syndrome was the only significant parameter increasing the risk of death [HR = 3.40, 95% CI (1.05-10.98), P = 0.04].

CONCLUSION

The cumulative incidence of pre-engraftment bacteremia and pneumonia was 14.3% and 11.2% respectively in this cohort. Aplastic anemia predicted for the occurrence of bacteremia, increasing patient age contributed to the occurrence of pneumonia, and myelodysplastic syndrome increased the risk of death.

Bacteremia in pediatric patients with hematopoietic stem cell transplantation

BACKGROUND

This study aimed to describe the incidence, microbiological profile, and risk factors associated with bacteremia in pediatric patients with hematopoietic stem cell transplantation (HSCT).

METHODS

A retrospective cohort study was performed on patients under 18 years old who underwent HSCT due to any indication, between January 2012 and January 2017. The patient data were collected from the first 100 days post-HSCT. Bacteremia was defined as the isolation of bacteria from at least one blood culture. The relation between bacteremia and associated risk factors was evaluated using univariate and multivariate analysis.

RESULTS

We enrolled a total of 111 pediatric patients who received HSCT during the period of study. The total number of patients who developed at least one episode of bacteremia was 46 (41.4%), and the total number of bacteremia episodes was 62. Rectal swabs were performed in 44 patients to detect prior colonization and this showed that 25% of them were positive, the main pathogen isolated being carbapenem-resistant enterobacteriaceae. The Gram-negative bacteria cases accounted for 60% of 62 events. The main Gram-negative bacteria isolated were Klebsiella pneumoniae and Escherichia coli and the majority were resistant strains. The mortality rate on day +100 for the whole cohort was 18% (n=20). Regarding the patients with bacteremia, the mortality rate on day +100 was 30% (n=14), and the cause of death was related to infection in 10 of them. We did not find any statistically significant risk factor for the development of bacteremia.

CONCLUSION

Bacteremia is common after HSCT, and there is a high frequency of resistant Gram-negative infections which is related to high mortality.

Low pre-transplant levels of mannose-binding lectin are associated with viral infections and mortality after haematopoietic allogeneic stem cell transplantation

BACKGROUND

Mannose-binding lectin (MBL) is a key component of innate immunity. Low serum MBL levels, related to promoter polymorphism and structural variants, have been associated with an increased risk of infection. The aim of this work was to analyse the incidence and severity of infections and mortality in relation to the MBL2 genotype and MBL levels in patients underwent allogeneic haematopoietic stem cell transplantation (Allo-HSCT).

RESULTS

This was a prospective cohort study of 72 consecutive patients underwent Allo-HSCT between January 2007 and June 2009 in a tertiary referral centre. Three periods were considered in the patients' follow-up: the early period (0-30 days after Allo-HSCT), the intermediate period (30-100 days after Allo-HSCT) and the late period (> 100 days after Allo-HSCT). A commercial line probe assay for MBL2 genotyping and an ELISA Kit were used to measure MBL levels. A total of 220 episodes of infection were collected in the 72 patients. No association between donor or recipient MBL2 genotype and infection was found. The first episode of infection presented earlier in patients with pre-transplant MBL levels of < 1000 ng/ml (median 6d vs 8d, p = 0.036). MBL levels < 1000 ng/ml in the pre-transplant period (risk ratio (RR) 2.48, 95% CI 1.00-6.13), neutropenic period (0-30 days, RR 3.28, 95% CI 1.53-7.06) and intermediate period (30-100 days, RR 2.37, 95% CI 1.15-4.90) were associated with increased risk of virus infection. No association with bacterial or fungal disease was found. Mortality was associated with pre-transplant MBL levels < 1000 ng/ml (hazard ratio 5.55, 95% CI 1.17-26.30, p = 0.03) but not with MBL2 genotype.

CONCLUSIONS

Patients who underwent Allo-HSCT with low pre-transplant MBL levels presented the first episode of infection earlier and had an increased risk of viral infections and mortality in the first 6 months post-transplant. Thus, pre-transplant MBL levels would be important in predicting susceptibility to viral infections and mortality and might be considered a biomarker to be included in the pre-transplantation risk assessment.

Immune Reconstitution Disorders: Spotlight on Interferons

Three decades of research in hematopoietic stem cell transplantation and HIV/AIDS fields have shaped a picture of immune restoration disorders. This manuscript overviews the molecular biology of interferon networks, the molecular pathogenesis of immune reconstitution inflammatory syndrome, and post-hematopoietic stem cell transplantation immune restoration disorders (IRD). It also summarizes the effects of thymic involution on T cell diversity, and the results of the assessment of diagnostic biomarkers of IRD, and tested targeted immunomodulatory treatments.

Bacterial blood stream infections (BSIs), particularly post-engraftment BSIs, are associated with increased mortality after allogeneic hematopoietic cell transplantation

We analyzed CIBMTR data to evaluate the incidence of non-relapse mortality (NRM) and association with overall survival (OS) for Bacterial blood stream infections (BSIs) occurring within 100 days of alloHCT in 2 different phases: pre/peri engraftment (BSI very early phase, BSI-VEP) and BSI post engraftment (BSI occurring between 2 weeks after engraftment and Day100, late early phase, BSI-LEP). Of 7,128 alloHCT patients, 2,656 (37%) had ≥1 BSI by day100. BSI-VEP, BSI-LEP, BSI-Both constituted 56% (n=1492), 31% (n=824), and 13% (n=340) of total BSI, respectively. Starting in 2009 we observed a gradual decline in BSI incidence through 2012 (61% to 48%). Patients with BSI-VEP were more likely to receive a myeloablative conditioning (MAC) regimen with total body irradiation (TBI). NRM was significantly higher in patients with any BSI (RR 1.82 95CI 1.63–2.04 for BSI-VEP, RR 2.46, 95%CI 2.05–2.96 for BSI-LEP, and RR 2.29, 95%CI 1.87–2.81 for BSI-Both) compared with those without BSI. OS was significantly lower in patients with any BSI compared with patients without BSI (RR 1.36, 95%CI 1.26–1.47 for BSI-VEP; RR 1.83, 95%CI 1.58–2.12 for BSI-LEP: RR 1.66, 95%CI 1.43–1.94 for BSI-Both). BSIs within day100 after alloHCT are common and remain a risk factor for mortality.

Diagnosis of cytomegalovirus pneumonia by quantitative polymerase chain reaction using bronchial washing fluid from patients with hematologic malignancies

Background

The incidence of cytomegalovirus (CMV) pneumonia is increasing in patients diagnosed with hematologic malignancies. The utility of CMV-DNA viral load measurement has not been standardized, and viral cut-off values have not been established. This study was designed to investigate the utility of CMV quantitative real-time PCR (qRT-PCR) using bronchial washing fluid.

Methods

We retrospectively reviewed the microbiologic and pathologic results of bronchial washing fluid and biopsy specimens in addition to the patients' clinical characteristics.

Results

A total of 565 CMV qRT-PCR assays were performed using bronchial washing fluid from patients with hematologic malignancies. Among them, 101 were positive for CMV by qRT-PCR; of these, 24 were diagnosed with CMV pneumonia and 70 with CMV infection, and 7 were excluded due to a diagnosis of invasive pulmonary aspergillosis rather than viral pneumonia. The median CMV load determined by qPCR was 1.8 × 10⁵ copies/mL (3.6 10³-1.5 × 10⁸) in CMV pneumonia patients and 3.0 × 10³ copies/mL (5.0 × 10²-1.1 × 10⁵) in those diagnosed with CMV infection (P < 0.01). Using the ROC curve, the optimal inflection points were 18,900 copies/mL (137,970 IU/mL) in post-bone marrow transplantation (BMT) patients, 316,415 copies/mL (2,309,825 IU/mL) in no-BMT patients and 28,774 copies/mL (210,054 IU/mL) in all patients.

Conclusions

The CMV titers in bronchial washing fluid determined by qRT-PCR differed significantly between patients diagnosed with CMV pneumonia and those with CMV infection. The viral cut-off values in bronchial washing fluid were suggested for the diagnosis of CMV pneumonia, which were different depending on the BMT status.

Infectious complications after hematopoietic stem cell transplantation: current status and future perspectives in Korea

Hematopoietic stem cell transplantation (HSCT) is a treatment for hematologic malignancies, immune deficiencies, or genetic diseases, ect. Recently, the number of HSCTs performed in Korea has increased and the outcomes have improved. However, infectious complications account for most of the morbidity and mortality after HSCT. Post-HSCT infectious complications are usually classified according to the time after HSCT: pre-engraftment, immediate post-engraftment, and late post-engraftment period. In addition, the types and risk factors of infectious complications differ according to the stem cell source, donor type, conditioning intensity, region, prophylaxis strategy, and comorbidities, such as graft-versushost disease and invasive fungal infection. In this review, we summarize infectious complications after HSCT, focusing on the Korean perspectives.

Complications of central venous catheter in patients transplanted with hematopoietic stem cells in a specialized service

Objective:

to identify the model, average length of stay on site and complications of central venous catheter in patients undergoing transplant of hematopoietic stem cells and verify the corresponding relationship between the variables: age, gender, medical diagnosis, type of transplant, implanted catheter and insertion site.

Method:

a retrospective and quantitative study with a sample of 188 patients transplanted records between 2007 and 2011.

Results:

the majority of patients used Hickman catheter with an average length of stay on site of 47.6 days. The complication fever/bacteremia was significant in young males with non-Hodgkin's lymphoma undergoing autologous transplant, which remained with the device for a long period in the subclavian vein.

Conclusion:

nurses should plan with their team the minimum waiting time, recommended between the catheter insertion and start of the conditioning regimen, as well as not to extend the length of time that catheter should be on site and undertake their continuing education, focusing on the prevention of complications.

Bacterial bloodstream infections in the allogeneic hematopoietic cell transplant patient: new considerations for a persistent nemesis

Bacterial bloodstream infections (BSI) cause significant transplant-related morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). This manuscript reviews the risk factors for and the bacterial pathogens causing BSIs in allo-HCT recipients in the contemporary transplant period. In addition, it offers insight into emerging resistant pathogens and reviews clinical management considerations to treat and strategies to prevent BSIs in allo-HCT patients.

Voriconazole for prophylaxis of invasive fungal infections after allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Invasive fungal infections (IFIs) following allogeneic hematopoietic stem cell transplantation (alloHSCT) are associated with a high mortality, and accordingly most alloHSCT recipients receive prophylaxis with antifungal agents. Despite some improvement in outcomes of IFIs over time, they continue to represent substantial clinical risk, mortality, and financial burden. Areas covered: We review the main pathogens responsible for IFIs in recipients of alloHSCT, current treatment recommendations, and discuss clinical and economic considerations associated with voriconazole prophylaxis of IFIs in these patients. Expert commentary: The clinical efficacy of voriconazole appears to be at least equivalent to other antifungal treatments, and generally well tolerated. Overall, benefit-risk balance is favorable, and findings from cost-effectiveness analyses support the use of voriconazole prophylaxis of IFIs in recipients of alloHSCT.

The demanding attention of tuberculosis in allogeneic hematopoietic stem cell transplantation recipients: High incidence compared with general population

BACKGROUND

The risk of developing tuberculosis (TB) in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is expected to be relatively high in an intermediate TB burden country. This single-center retrospective study was conducted to investigate risk factors and the incidence of TB after allogeneic HSCT.

METHODS

From January 2004 to March 2011, 845 adult patients were enrolled. Starting April 2009, patients were given isoniazid (INH) prophylaxis based on interferon-γ release assay results. The incidence of TB was analyzed before and after April 2009, and compared it with that of the general population in Korea.

RESULTS

TB was diagnosed in 21 (2.49%) of the 845 allogeneic HSCT patients. The median time to the development of TB was 386 days after transplantation (range, 49-886). Compared with the general population, the standardized incidence ratio of TB was 9.10 (95% CI; 5.59-14.79). Extensive chronic graft-versus-host disease (GVHD) was associated with the development of TB (P = 0.003). Acute GVHD, conditioning regimen with total body irradiation and conditioning intensity were not significantly related. INH prophylaxis did not reduce the incidence of TB (P = 0.548). Among 21 TB patients, one patient had INH prophylaxis.

CONCLUSION

Allogeneic HSCT recipients especially those who suffer from extensive chronic GVHD are at a high risk of developing TB. INH prophylaxis did not statistically change the incidence of TB, however, further well-designed prospective studies are needed.

Serious fungal infections in Korea

Information on the incidence and prevalence of fungal infections is of critical value in public health policy. However, nationwide epidemiological data on fungal infections are scarce, due to a lack of surveillance and funding. The objective of this study was to estimate the disease burden of fungal infections in the Republic of Korea. An actuarial approach using a deterministic model was used for the estimation. Data on the number of populations at risk and the frequencies of fungal infections in those populations were obtained from national statistics reports and epidemiology papers. Approximately 1 million people were estimated to be affected by fungal infections every year. The burdens of candidemia (4.12 per 100,000), cryptococcal meningitis (0.09 per 100,000), and Pneumocystis pneumonia (0.51 per 100,000) in South Korea were estimated to be comparable to those in other countries. The prevalence of chronic pulmonary aspergillosis (22.4 per 100,000) was markedly high, probably due to the high burden of tuberculosis in Korea. The low burdens of allergic bronchopulmonary aspergillosis (56.9 per 100,000) and severe asthma with fungal sensitization (75.1 per 100,000) warrant further study. Oral candidiasis (539 per 100,000) was estimated to affect a much larger population than noted in previous studies. Our work provides valuable insight on the epidemiology of fungal infections; however, additional studies are needed.

A Review of Myeloablative vs Reduced Intensity/Non-Myeloablative Regimens in Allogeneic Hematopoietic Stem Cell Transplantations

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is a curative treatment option for both malignant and some benign hematological diseases. During the last decade, many of the newer high-dose regimens in different intensity have been developed specifically for patients with hematologic malignancies and solid tumors. Today there are three main approaches used prior to allogeneic transplantation: Myeloablative (MA), Reduced Intensity Conditioning (RIC) and Non-MA (NMA) regimens. MA regimens cause irreversible cytopenia and there is a requirement for stem cell support. Patients who receive NMA regimen have minimal cytopenia and this type of regimen can be given without stem cell support. RIC regimens do not fit the criteria of MA and NMA: the cytopenia is reversible and the stem cell support is necessary. NMA/RIC for Allo-HSCT has opened a new era for treating elderly patients and those with comorbidities. The RIC conditioning was used for 40% of all Allo-HSCT and this trend continue to increase. In this paper, we will review these regimens in the setting of especially allogeneic HSCT and our aim is to describe the history, features and impact of these conditioning regimens on specific diseases.

The immune response to cytomegalovirus in allogeneic hematopoietic stem cell transplant recipients

Approximately, up to 70 % of the human population is infected with cytomegalovirus (CMV) that persists for life in a latent state. In healthy people, CMV reactivation induces the expansion of CMV-specific T cells up to 10 % of the entire T cell repertoire. On the contrary, CMV infection is a major opportunistic viral pathogen that remains a leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Due to the delayed CMV-specific immune recovery, the incidence of CMV reactivation during post-transplant period is very high. Several methods are currently available for the monitoring of CMV-specific responses that help in clinical monitoring. In this review, essential aspects in the immune recovery against CMV are discussed to improve the better understanding of the immune system relying on CMV infection and, thereby, helping the avoidance of CMV disease or reactivation following hematopoietic stem cell transplantation with severe consequences for the transplanted patients.

Fungal and viral infections after allogeneic hematopoietic transplantation from unrelated donors in adults: improving outcomes over time

Umbilical cord blood (CB) is increasingly used as an alternative source of stem cells in adult unrelated transplantation. Although registry studies report similar overall outcomes in comparison with BM/PB, comparative studies focusing on severe infections and infection-RM (IRM) with a long follow-up are scarce. A total of 434 consecutive unrelated transplants (1997-2009) were retrospectively analyzed to compare overall outcomes, incidence and risk factors of severe viral and invasive fungal infections in CB (n=65) vs BM/PB recipients (n=369). The 5-year OS was 38 vs 43%, respectively (P=0.2). CB transplantation (CBT) was associated with a higher risk of invasive aspergillosis (100-days-cumulative incidence 16 vs 6%, P=0.04) and CMV infection without differences in RM. No statistically significant differences were found regarding NRM (NRM of 38% in CB vs 37% in BM/PB at 1 year) nor IRM (30% in CB vs 27% in BM/PB at 1 year). In the overall population, NRM and IRM improved in more recent years. In adults who receive a single CBT, the risk of severe infections is increased when compared with unrelated BM/PB recipients, but mortality from infections is similar, leading to similar NRM and survival.

Invasive diagnostic strategies in immunosuppressed patients with acute respiratory distress syndrome

Immunosuppression predisposes the host to development of pulmonary infections, which can lead to respiratory failure and the development of acute respiratory distress syndrome (ARDS). There are multiple mechanisms by which a host can be immunosuppressed and each is associated with specific infectious pathogens. Early invasive diagnostic modalities such as fiber-optic bronchoscopy with bronchoalveolar lavage, transbronchial biopsy, and open lung biopsy are complementary to serologic and noninvasive studies and assist in rapidly establishing an accurate diagnosis, which allows initiation of appropriate therapy and may improve outcomes with relative safety.

Improving cytomegalovirus-specific T cell reconstitution after haploidentical stem cell transplantation

Cytomegalovirus (CMV) infection and delayed immune reconstitution (IR) remain serious obstacles for successful haploidentical stem cell transplantation (haplo-SCT). CMV-specific IR varied according to whether patients received manipulated/unmanipulated grafts or myeloablative/reduced intensity conditioning. CMV infection commonly occurs following impaired IR of T cell and its subsets. Here, we discuss the factors that influence IR based on currently available evidence. Adoptive transfer of donor T cells to improve CMV-specific IR is discussed. One should choose grafts from CMV-positive donors for transplant into CMV-positive recipients (D+/R+) because this will result in better IR than would grafts from CMV-negative donors (D−/R+). Stem cell source and donor age are other important factors. Posttransplant complications, including graft-versus-host disease and CMV infection, as well as their associated treatments, should also be considered. The effects of varying degrees of HLA disparity and conditioning regimens are more controversial. As many of these factors and strategies are considered in the setting of haplo-SCT, it is anticipated that haplo-SCT will continue to advance, further expanding our understanding of IR and CMV infection.

NOD2/CARD15 single nucleotide polymorphism 13 (3020insC) is associated with risk of sepsis and single nucleotide polymorphism 8 (2104C>T) with herpes viruses reactivation in patients after allogeneic hematopoietic stem cell transplantation

Three NOD2 polymorphisms (single nucleotide polymorphism [SNP]8 [2104C>T, Arg702Trp], SNP12 [2722G>C, Gly908Arg], and SNP13 [3020insC, Leu1007 fsins C]), identified as disease-associated variants in Crohn's disease, have recently been suggested as gene markers of the outcome of hematopoietic stem cell transplantation (HSCT). In the present multicenter study of 464 donor-recipient pairs, we focused on the effect of NOD2 mutation(s) on the risk of infections and acute graft-versus-host disease (aGVHD). The presence of SNP13 in recipients, donors, or both was more frequently seen in patients having sepsis than in those lacking sepsis (9 of 48 versus 33 of 386, P = .046). The presence of SNP8 (recipient and/or donor positive) was associated with a higher rate of Herpes viruses reactivation (17 of 21 versus 86 of 173, P = .007). In the SNP8-positive group, a trend for a higher rate of bacteremia well controlled by antibiotics was found (9 of 10 versus 47 of 81, P = .106). In contrast, the presence of SNP13 in recipient and/or donor resulted in a poor response to antibiotics (5 of 11 versus 9 of 10, P = .042). A statistically significant association between the presence of NOD2 SNPs and acute grade > II GVHD was found in a subgroup of HSCT patients who received transplants from unrelated donors with a myeloablative conditioning regimen that included antithymocyte globulin (ATG). In this subgroup of patients, donor positivity for any SNPs investigated (7 of 18 versus 17 of 113, P = .036) and, independently, only the presence of SNP8 (4 of 8 versus 20 of 123, P = .055) were associated with severe grade ≥ II aGVHD. In conclusion, SNP8 positivity in donors or recipients makes patients more prone to Herpes viruses reactivation and bacteremia but not to sepsis. Septic complications were associated with SNP13 polymorphism. SNP8 in donors constitutes a risk factor of severe aGVHD, but only if patients received transplants from unrelated donors and received ATG as part of a conditioning regimen.

Defective pulmonary innate immune responses post-stem cell transplantation; review and results from one model system

Infectious pulmonary complications limit the success of hematopoietic stem cell transplantation (HSCT) as a therapy for malignant and non-malignant disorders. Susceptibility to pathogens in both autologous and allogeneic HSCT recipients persists despite successful immune reconstitution. As studying the causal effects of these immune defects in the human population can be limiting, a bone marrow transplant (BMT) mouse model can be used to understand the defect in mounting a productive innate immune response post-transplantation. When syngeneic BMT is performed, this system allows the study of BMT-induced alterations in innate immune cell function that are independent of the confounding effects of immunosuppressive therapy and graft-versus-host disease. Studies from several laboratories, including our own show that pulmonary susceptibility to bacterial infections post-BMT are largely due to alterations in the lung alveolar macrophages. Changes in these cells post-BMT include cytokine and eicosanoid dysregulations, scavenger receptor alterations, changes in micro RNA profiles, and alterations in intracellular signaling molecules that limit bacterial phagocytosis and killing. The changes that occur highlight mechanisms that promote susceptibility to infections commonly afflicting HSCT recipients and provide insight into therapeutic targets that may improve patient outcomes post-HSCT.

Escherichia coli and Klebsiella pneumoniae bacteremia in patients with neutropenic fever: factors associated with extended-spectrum β-lactamase production and its impact on outcome

Escherichia coli and Klebsiella pneumoniae are main pathogens in neutropenic fever even if the proportion of Gram-positive cocci is increasing. Extended-spectrum β-lactamases (ESBL)-producing organisms are an emerging problem in nosocomial infection. Nevertheless, until now, information about risk factors for the acquisition and clinical outcomes of bacteremia due to ESBL-producing organisms is limited in neutropenic patients. From medical records collected between January 2007 and December 2008, we identified a total of 101 consecutive patients who developed bacteremia due to E. coli (n = 87) or K. pneumoniae (n = 14). Twenty-six (26 %) cases of bacteremia were caused by ESBL-producing organisms. A hospital stay of >2 weeks during the 3 months preceding bacteremia [adjusted odds ratio (OR), 5.887; 95 % confidence interval (CI), 1.572-22.041] and the use of broad-spectrum cephalosporins in the 4 weeks prior to bacteremia (adjusted OR, 6.186; 95 % CI, 1.616-23.683) were significantly related to the acquisition of ESBL. Twenty-four (92 %) of the ESBL-producing organisms were susceptible to either piperacillin-tazobactam or amikacin. Aminoglycosides (amikacin or isepamicin) were the main appropriate antimicrobial agents used against the ESBL-producing isolates during the initial empirical treatment (16/22, 73 %). However, the 30-day mortality rates for ESBL bacteremia and non-ESBL bacteremia were not significantly different (15 vs 5 %; p = 0.199). As alternatives to carbapenem, piperacillin-tazobactam plus amikacin or isepamicin combinations may be effective empirical therapeutic options for patients with neutropenic fever who are at high risk of developing bacteremia with ESBL-producing pathogens.