High rate of invasive fungal infections following nonmyeloablative allogeneic transplantation

Revisit of the Association between Cytomegalovirus Infection and Invasive Fungal Infection after Allogeneic Hematopoietic Stem Cell Transplantation: A Real-World Analysis from a High CMV Seroprevalence Area

Infection is a major complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) especially cytomegalovirus (CMV) infection and invasive fungal infection (IFI). Taiwan is a high CMV seroprevalence area. Our study aimed to evaluate the incidence, risk factors, the impact on survival of CMV infection (including reactivation and disease) and the association of CMV infection and IFI in recipients after allo-HSCT during the first 100 days after transplantation. This was a retrospective study including 180 recipients of allo-HSCT. A total of 99 patients had CMV reactivation, and nine patients had CMV diseases. There were more mismatched donors, more ATG usage and more transplantation from CMV IgG-negative donor in patients with CMV reactivation. There was no survival difference in patients with or without CMV reactivation. A total of 34 patients had IFIs, and IFI after allo-HSCT was associated with significantly inferior survival. Patients with CMV reactivation did not increase the incidence of overall IFI, but they did result in more late-onset (>40 days) IFI (p = 0.056). In this study, we demonstrated real-world data of CMV infection and IFI from a high CMV seroprevalence area.

How I perform hematopoietic stem cell transplantation on patients with a history of invasive fungal disease

Hematopoietic transplantation is the preferred treatment for many patients with hematologic malignancies. Some patients may develop invasive fungal diseases (IFDs) during initial chemotherapy, which need to be considered when assessing patients for transplantation and treatment posttransplantation. Given the associated high risk of relapse and mortality in the post-hematopoietic stem cell transplantation (HSCT) period, IFDs, especially invasive mold diseases, were historically considered a contraindication for HSCT. Over the last 3 decades, advances in antifungal drugs and early diagnosis have improved IFD outcomes, and HSCT in patients with a recent IFD has become increasingly common. However, an organized approach for performing transplantation in patients with a prior IFD is scarce, and decisions are highly individualized. Patient-, malignancy-, transplantation procedure-, antifungal treatment-, and fungus-specific issues affect the risk of IFD relapse. Effective surveillance to detect IFD relapse post-HSCT and careful drug selection for antifungal prophylaxis are of paramount importance. Antifungal drugs have their own toxicities and interact with immunosuppressive drugs such as calcineurin inhibitors. Immune adjunct cytokine or cellular therapy and surgery can be considered in selected cases. In this review, we critically evaluate these factors and provide guidance for the complex decision making involved in the peri-HSCT management of these patients.

Evaluation of bioactivities of zinc oxide, cadmium sulfide and cadmium sulfide loaded zinc oxide nanostructured materials prepared by nanosecond pulsed laser

The present study reports the preparation of cadmium sulfide (CdS) loaded zinc oxide (ZnO) nanostructured semiconductor material and its anti-bioactivity studies against cancerous and fungus cells. For composite preparation, two different mass ratios of CdS (10 and 20%) were loaded on ZnO (10%CdS/ZnO, 20%CdS/ZnO) using a 532 nm pulsed laser ablation in water media. The structural and morphological analyses confirmed the successful loading of nanoscaled CdS on the surface of ZnO particles, ZnO particles were largely spherical with average size ~50 nm, while CdS about 12 nm in size. The elemental and electron diffraction analyses reveal that the prepared composite, CdS/ZnO contained both CdS and ZnO, thus reaffirming the production of CdS loaded ZnO. The microscopic examination and MTT assay showed the significant impact of ZnO, CdS, and CdS loaded ZnO on human colorectal carcinoma cells (HCT-116 cells). Our results show that the prepared ZnO had better anticancer activities than individual CdS, and CdS loaded ZnO against cancerous cells. For antifungal efficacy, as-prepared nanomaterials were investigated against Candida albicans by examining minimum inhibitory/fungicidal concentration (MIC/MFC) and morphogenesis. The lowest MIC (0.5 mg/mL), and MFC values (1 mg/mL) were found for 10 and 20%CdS/ZnO. Furthermore, the morphological analyses reveal the severe damage of the cell membrane upon exposure of Candida strains to nanomaterials. The present study suggests that ZnO, CdS, and CdS loaded ZnO nanostructured materials possess potential anti-cancer and anti-fungal activities.

Overview of Infections in the Immunocompromised Host

Understanding the components of the immune system that contribute to host defense against infection is key to recognizing infections that are more likely to occur in an immunocompromised patient. In this review, we discuss the integrated system of physical barriers and of innate and adaptive immunity that contributes to host defense. Specific defects in the components of this system that predispose to particular infections are presented. This is followed by a review of primary immunodeficiency diseases and secondary immunodeficiencies, the latter of which develop because of a specific illness or condition or are treatment-related. The effects of treatment for neoplasia, autoimmune diseases, solid organ and stem cell transplants on host defenses are reviewed and associated with susceptibility to particular infections. In conclusion, an approach to laboratory screening for a suspected immunodeficiency is presented. Knowledge of which host defects predispose to specific infections allows clinicians to prevent, diagnose, and manage infections in their immunocompromised patients most effectively.

A novel scoring system to predict the incidence of invasive fungal disease in salvage chemotherapies for malignant lymphoma

The requirement of antifungal prophylaxis has not been established in the chemotherapies for malignant lymphoma. This study was conducted to explore the incidence of invasive fungal diseases (IFD) and their risk factors in patients receiving salvage therapies for malignant lymphoma. We retrospectively analyzed 177 consecutive patients who received these therapies (705 courses in total) at our institute. IFD were observed in 16 courses and the incidence was 2.3 %. A multivariate analysis showed that the factors associated with IFD were primary refractoriness (adjusted odds ratio (aOR), 4.22; 95 % confidence interval (CI), 1.38-13.0; p value = 0.012), two (aOR, 10.5, 95 % CI, 1.20-91.7; p = 0.033) or more (aOR, 26.2; 95 % CI, 3.27-210; p = 0.002) previous treatment lines, and the minimum neutrophil count during the therapies equal to or less than 500/μL (aOR, 9.69; 95 % CI, 1.25-74.9; p = 0.030). Using these factors, we created the IFD scoring model by assigning one point to each of primary refractoriness, two previous treatment lines and treatment that caused neutropenia (≤500/μL minimal neutrophil count) and two points to three or more previous treatment lines. The IFD incidence of lower risk group (IFD score <3) was 0.19 % and that of higher (IFD score ≥3) was 9.0 %. In conclusion, adequate prophylaxis for IFD might be required for patients with primary refractoriness, repeated therapies, or therapies which cause neutropenia. Furthermore, the IFD scoring model of this study underscores the need to account for disease and host factors in determining administration of adequate prophylaxis in salvage treatments for malignant lymphoma.

Histone methyltransferase and histone methylation in inflammatory T-cell responses

During immune responses, T cells require tightly controlled expression of transcriptional programs to regulate the balance between beneficial and harmful immunity. These transcriptional programs are critical for the lineage specification of effector T cells, the production of effector cytokines and molecules, and the development and maintenance of memory T cells. An emerging theme is that post-translational modification of histones by methylation plays an important role in orchestrating the expression of transcriptional programs in T cells. In this article, we provide a broad overview of histone methylation signatures for effector molecules and transcription factors in T cells, and the functional importance of histone methyltransferases in regulating T-cell immune responses.

The Aspergillus fumigatus β-1,3-glucanosyltransferase Gel7 plays a compensatory role in maintaining cell wall integrity under stress conditions

Aspergillus fumigatus is an opportunistic fungal pathogen that causes fatal invasive aspergillosis among immunocompromised patients. The cell wall β-1,3-glucan is mainly elongated by β-1,3-glucanosyltransferase Gel family, which is vital for growth and virulence of A. fumigatus. Although seven members of Gels have been annotated, only Gel1, Gel2 and Gel4 were characterized. In this study, the function of Gel7 was analyzed for the first time, by constructing Δgel7, Δgel7Δcwh41 and Δgel1Δgel7Δcwh41 separately. Disruption of gel7 alone did not result in any obvious phenotype except an abnormality in conidia formation, whereas Δgel7Δcwh41 and Δgel1Δgel7Δcwh41 exhibited abnormal conidiogenesis, a heat-induced delay of germination and a severe decrease in β-1,3-glucan content. Our results suggested that the A. fumigatus β-1,3-glucanosyltransferase Gel7 was involved in conidiation and was compensated for the cell wall β-1,3-glucan defects when Gel1 and Gel2 lost their functions, especially at an elevated temperature.

Antifungal prophylaxis among allogeneic hematopoietic stem cell transplant recipients: current issues and new agents

Invasive candidiasis and invasive mold infections cause significant morbidity and mortality in the hematopoietic stem cell transplant population, in particular in recipients of allografts. The introduction of a variety of new antifungal compounds over the past decade has focused attention on prophylactic strategies as a means to decrease the burden of invasive fungal infections (IFIs). Until recently, fluconazole has been the standard agent for prophylaxis before and after engraftment. In 2005, the echinocandin micafungin received US FDA approval for prophylaxis against IFIs in stem cell transplant recipients during the neutropenic period prior to engraftment. In patients with substantial risk for invasive mold infection, many centers now use a mold-active antifungal agent (e.g., a triazole such as itraconazole, voriconazole or posaconazole, or an echinocandin) as prophylaxis after engraftment. Several recent studies have highlighted the efficacy of these newer agents in preventing IFIs in these highly immunocompromised patients. This review will discuss current issues in IFI and new agents available for prophylaxis in allogeneic hematopoietic stem cell transplant recipients.

Immune Reconstitution and Early Infectious Complications Following Nonmyeloablative Hematopoietic Stem Cell Transplantation

Non-myeloablative stem cell transplantation (NMT) has been increasingly used in compromised patients who would otherwise have been unable to undergo allotransplant. There is little understanding of the kinetics of immune reconstitution and its influence on infective complications following NMT. The aim of present study was to evaluate lymphocyte subset reconstitution over the first 12 months post-transplant in 15 adult patients receiving NMT with comparison to that of 30 patients grafted with a conventional hemopoietic stem cell transplantation (HSCT). NMT recipients were conditioned with fludarabine-based conditioning regimens. Peripheral blood stem cell (PBSC) was the source of stem cells in 13 NMT recipients and in 24 conventional HSCT recipients. Absolute numbers of helper (CD4+) T cells, naive (CD4+ CD45RA+) and memory (CD4+ CD45RO+) T cells as well as suppressor (CD8+) T cells, CD19+ B cells and NK cells were comparable in the two groups at all time points after transplantation. A median value of 200 CD4+ T cells/microl was achieved at 2 months post-transplant by the NMT and HSCT recipients. The CD4:CD8 ratio remained severely depressed throughout the study period. Almost all CD4+ lymphocytes expressed CD45RO antigen in the both groups of patients B lymphocytes showed low counts throughout the entire study period in both groups. Bacteremia and CMV antigenemia occurred respectively in 13 and 36% of the patients in the NMT group and in 15 and 39% of the patients in the HSCT group. Our preliminary data indicate that patients receiving a NMT have a lymphocyte reconstitution similar to that observed in patients who received a conventional HSCT. The incidence of bacteremia and CMV infection were not significantly different between the groups. Nevertheless, due to the small sample size, these results should be considered suggestive rather than definitive.

Risk factors for invasive fungal disease after allogeneic hematopoietic stem cell transplantation: a single center experience

Invasive fungal disease (IFD) is a major cause of morbidity and mortality after hematopoietic stem cell transplantation (HCT). We performed a retrospective review of 271 adults with a hematologic malignancy undergoing allogeneic HCT to determine the incidence of and risk factors for IFD and to examine the impact of IFD on nonrelapse mortality and overall survival. We defined IFD using standard criteria and selected proven and probable cases for analysis. Diagnoses in the study group included acute leukemia (42%), non-Hodgkin lymphoma (24%), myelodysplastic syndrome (15%), chronic lymphocytic leukemia (5%), and other hematologic disorders (14%). Conditioning included reduced-intensity (64%) and myeloablative (36%) regimens. Donor sources were HLA-matched sibling (60%), matched unrelated (20%), haploidentical (12%), and cord blood (8%). A total of 51 episodes of IFD were observed in 42 subjects (15%). Aspergillus spp (47%) was the most frequent causative organism, followed by Candida spp (43%). The majority of IFD cases (67%) were reported after day +100 post-HCT. In multivariate analysis, haploidentical donor transplantation (hazard ratio [HR], 3.82; 95% confidence interval [CI], 1.49-9.77; P = .005) and grade II-IV acute graft-versus-host disease (HR, 2.55; 95% CI, 1.07-6.10; P = .03) were risk factors for the development of IFD. Conversely, higher infused CD34(+) cell dose was associated with a lower risk of IFD (HR, 0.80; 95% CI, 0.68-0.94; P = .006, per 1 × 10(6) cells/kg increase in CD34(+) cell infusion). IFD-related mortality was 33.3%. Nonrelapse mortality was significantly higher in patients who developed IFD compared with those without IFD (P < .001, log-rank test). Patients with IFD had lower overall survival (5.8 months versus 76.1 months; P < .001, log-rank test). Further studies exploring strategies to increase the infused cell dose and determine adequate prophylaxis, especially against aspergillus, beyond day +100 are needed.

N-Glycosylation of Gel1 or Gel2 is vital for cell wall β-glucan synthesis in Aspergillus fumigatus

Fungal cell wall is a dynamic structure that communicates with and protects the cell from outside stress. In Aspergillus fumigatus, the cell wall β-glucans are mainly elongated by β-1,3-glucanosyltransferases Gels, which consist of seven family members (Gel1-7) utilizing β-1,3-glucan chains as substrates. Previously, we have shown that the mutant deficient of N-glycan processing displays a reduction in the cell wall β-glucans, suggesting that N-glycosylation is required for the proper function of β-1,3-glucanosyltransferase. To verify this hypothesis, in this study, the gene encoding β-1,3-glucanosyltransferase Gel1 or Gel2 was deleted in the Δcwh41 mutant to construct a double-mutant Δgel1Δcwh41 or Δgel2Δcwh41. The growth phenotypes of both double mutants were similar to the single-mutant Δcwh41, suggesting that Gel1 and Gel2 are proteins that are mainly affected by deficient N-glycan processing in Δcwh41. Furthermore, the mutant Δgel1(Gel1-NM) or Δgel2(Gel2-NM), in which all potential N-glycosylation sites on Gel1 or Gel2 were removed by site-directed mutagenesis, showed phenotypes similar to the single-mutant Δgel1 or Δgel2. Biochemical analysis revealed that N-glycosylation was essential for the function of Gel1 or Gel2 and thus required for β-glucan synthesis in A. fumigatus.

Invasive fungal diseases in haematopoietic cell transplant recipients and in patients with acute myeloid leukaemia or myelodysplasia in Brazil

Invasive fungal disease (IFD) shows distinct regional incidence patterns and epidemiological features depending on the geographic region. We conducted a prospective survey in eight centres in Brazil from May 2007 to July 2009. All haematopoietic cell transplant (HCT) recipients and patients with acute myeloid leukaemia (AML) or myelodysplasia (MDS) were followed from admission until 1 year (HCT) or end of consolidation therapy (AML/MDS). The 12-month cumulative incidence (CI) of proven or probable IFD was calculated, and curves were compared using the Grey test. Among 237 AML/MDS patients and 700 HCT recipients (378 allogeneic, 322 autologous), the 1-year CI of IFD in AML/MDS, allogeneic HCT and autologous HCT was 18.7%, 11.3% and 1.9% (p <0.001), respectively. Fusariosis (23 episodes), aspergillosis (20 episodes) and candidiasis (11 episodes) were the most frequent IFD. The 1-year CI of aspergillosis and fusariosis in AML/MDS, allogeneic HCT and autologous HCT were 13.4%, 2.3% and 0% (p <0.001), and 5.2%, 3.8% and 0.6% (p 0.01), respectively. The 6-week probability of survival was 53%, and was lower in cases of fusariosis (41%). We observed a high burden of IFD and a high incidence and mortality for fusariosis in this first multicentre epidemiological study of IFD in haematological patients in Brazil.

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

BACKGROUND

In allogeneic stem cell transplantation (allo-SCT), reduced-intensity conditioning (RIC) is known for producing less regimen-related toxicity. However, whether or not RIC reduces the risk for infection and infection-related mortality (IRM) remains controversial.

METHODS

We retrospectively analyzed infectious episodes and IRMs after allo-SCTs by time period and by the intensity of the conditioning regimen (RIC [n = 81] vs. myeloablative conditioning, MAC [n = 150]).

RESULTS

The cumulative incidence of any kind of infection was lower in the RIC group through the entire period (72% vs. 87%; P = 0.007). The onset of infections was deferred in the RIC group as compared with the MAC group (P = 0.012). Bacteremia occurred less frequently in the RIC group through the entire period (5% vs. 14%; P = 0.044). However, the incidences of cytomegalovirus reactivation and disease, herpes zoster, virus-associated hemorrhagic cystitis, and invasive fungal infection were not different between the two groups. Furthermore, there was no difference in relapse-free survival and IRM between the two conditioning regimens.

CONCLUSION

Careful monitoring and appropriate preventive/therapeutic strategies for infectious complications, comparable to those for allo-SCT recipients with MAC, should also be applied to those with RIC, especially after engraftment.

Emerging moulds: epidemiological trends and antifungal resistance

Invasive fungal infections (IFIs) are associated with high morbidity and mortality in immunocompromised patients. Although Aspergillus spp. remain an important cause of IFI, other moulds such as Fusarium spp., dematiaceous fungi and Mucorales have become increasingly prevalent among this patient population. Diagnosis and treatment of invasive mould infections remain a challenge. Because of the poor prognosis associated with IFIs, understanding the activity, efficacy and limitations of the available drugs is critical to select the appropriate antifungal agent on an individualised basis.

What are fungal infections?

Yeasts and moulds now rank amongst the 10 most frequently isolated pathogens in febrile patients with an impaired immune system. Fungi are mainly opportunistic pathogens that only invade the body if a severely weakened natural defense permits them to do so. Most factors facilitating an invasive fungal infection are unavoidable because they are directly connected to the underlying diseases as well as to their treatment.Modern aggressive treatment modalities jeopardize the defense mechanisms to an extent that even fungi with a low virulence may enter the body.

Increased risk of bacterial infection after engraftment in patients treated with allogeneic bone marrow transplantation following reduced-intensity conditioning regimen

Although bacterial infection is a major cause of death even after reduced-intensity conditioning (RIC) for allogeneic stem cell transplantation (SCT), little is known about the epidemiology and risk factors. The incidence of bacterial infection in 43 patients who received allogeneic bone marrow transplantation (BMT) using a RIC regimen was compared with that in 68 patients who received BMT using a myeloablative conditioning regimen, and risk factors for bacterial infection were identified. Before engraftment, incidences of febrile neutropenia (FN) and documented infections (DI) were significantly decreased in RIC patients (FN: 59.5% vs. 89.6%, P<0.01, DI: 4.8% vs. 17.9%, P<0.01). However, incidence of bacterial infection was significantly increased in RIC patients in the post-engraftment phase (53.8% vs. 11.1%, log-rank, P<0.01). Blood stream was the most frequent focus of infection in both groups. In multivariate analysis, RIC and acute graft-versus-host disease were revealed to be significant risk factors for bacterial infection in this phase. In summary, risk of bacterial infection after engraftment was significantly higher in RIC patients, although infection was decreased before engraftment, and we need to develop a RIC-specific strategy against bacterial infection after RIC SCT.

Application of an oligonucleotide microarray-based nano-amplification technique for the detection of fungal pathogens

BACKGROUND

The traditional techniques for diagnosis of invasive fungal infections in the clinical microbiology laboratory need improvement. These techniques are prone to delay results due to their time-consuming process, or result in misidentification of the fungus due to low sensitivity or low specificity. The aim of this study was to develop a method for the rapid detection and identification of fungal pathogens.

METHODS

The internal transcribed spacer two fragments of fungal ribosomal DNA were amplified using a polymerase chain reaction for all samples. Next, the products were hybridized with the probes immobilized on the surface of a microarray. These species-specific probes were designed to detect nine different clinical pathogenic fungi including Candida albicans, Candida tropocalis, Candida glabrata, Candida parapsilosis, Candida krusei, Candida lusitaniae, Candida guilliermondii, Candida keyfr, and Cryptococcus neoformans. The hybridizing signals were enhanced with gold nanoparticles and silver deposition, and detected using a flatbed scanner or visually.

RESULTS

Fifty-nine strains of fungal pathogens, including standard and clinically isolated strains, were correctly identified by this method. The sensitivity of the assay for Candida albicans was 10 cells/mL. Ten cultures from clinical specimens and 12 clinical samples spiked with fungi were also identified correctly.

CONCLUSIONS

This technique offers a reliable alternative to conventional methods for the detection and identification of fungal pathogens. It has higher efficiency, specificity and sensitivity compared with other methods commonly used in the clinical laboratory.

Economic evaluation of posaconazole versus fluconazole prophylaxis in patients with graft-versus-host disease (GVHD) in the Netherlands

The objective of this study was to evaluate the cost-effectiveness of posaconazole versus fluconazole for the prevention of invasive fungal infections (IFI) in graft-versus-host disease (GVHD) patients in the Netherlands. A decision analytic model was developed based on a double-blind randomized trial that compared posaconazole with fluconazole antifungal prophylaxis in recipients of allogeneic HSCT with GVHD who were receiving immunosuppressive therapy (Ullmann et al., N Engl J Med 356:335–347, 2007). Clinical events were modeled with chance nodes reflecting probabilities of IFIs, IFI-related death, and death from other causes. Data on life expectancy, quality-of-life, medical resource consumption, and costs were obtained from the literature. The total cost with posaconazole amounted to €9,428 (95% uncertainty interval €7,743–11,388), which is €4,566 (€2,460–6,854) more than those with fluconazole. Posaconazole prophylaxis resulted in 0.17 (0.02–0.36) quality adjusted life year (QALY) gained compared to fluconazole prophylaxis, corresponding to an incremental cost effectiveness ratio (ICER) of €26,225 per QALY gained. A scenario analysis demonstrated that at an increased background IFI risk (from 9% to 15%) the ICER was €13,462 per QALY. Given the underlying data and assumptions, posaconazole prophylaxis is expected to be cost-effective relative to fluconazole in recipients of allogeneic HSCT developing GVHD in the Netherlands. The cost-effectiveness of posaconazole depends on the IFI risk, which can vary by hospital.

Voriconazole provides effective prophylaxis for invasive fungal infection in patients receiving glucocorticoid therapy for GVHD

Patients on systemic glucocorticoids for GVHD after hematopoietic cell transplant are susceptible to invasive fungal infections (IFI), which greatly contribute to morbidity and mortality. We evaluated the efficacy of prophylactic treatment options (voriconazole or fluconazole vs itraconazole) for IFI by performing a retrospective review of patients on glucocorticoids for GVHD who were administered voriconazole (n=97), fluconazole (n=36) or itraconazole (n=36). IFI developed in 7/72 (10%) patients on fluconazole/itraconazole vs 2/97 (2%) on voriconazole (P=0.03) within the first 100 days of glucocorticoids. Five (7%) patients developed Aspergillus IFI on fluconazole/itraconazole, compared with none on voriconazole (0%) (P=0.008); Aspergillus IFI resulted in death in all five patients. We found that IFI occurred in patients who received an initial dose of at least 2 mg/kg/day of prednisone or equivalent; when the analysis was restricted to these patients, the hazard ratio (0.39; 95% confidence interval: 0.08-1.86) was consistent with a protective effect of voriconazole compared with fluconazole/itraconazole, although this subset analysis did not reach significance. OS at 100 days after start of glucocorticoids was 77% in patients administered fluconazole/itraconazole and 85% in those administered voriconazole (P=0.22). Our results suggest that voriconazole is more effective than fluconazole/itraconazole in preventing IFI, especially aspergillosis, in patients receiving glucocorticoids post transplant.

Infections in non-myeloablative hematopoietic stem cell transplantation patients with lymphoid malignancies: spectrum of infections, predictors of outcome and proposed guidelines for fungal infection prevention

The overall risk of infections is lower in patients undergoing non-myeloablative allogeneic stem cell transplantation (NST) than in conventional stem cell transplant recipients. We sought to evaluate conditions associated with increased risk of infections after NST. In 81 patients, 187 infection episodes were noted; chronic lymphocytic leukemia (138 episodes/100 person-years) and recipients of matched unrelated donor graft (128 episodes/100 person-years) had higher risk of infection. Only half of the cytomegalovirus (CMV) infections occurred 31-100 days after transplantation. Most patients with CMV infection were non-neutropenic (100%), had lymphoma (76%), were younger (<55 years; 72%) and had received matched related donor (MRD) graft (72%). However, graft-versus-host disease (GVHD) was present in only 15% of these patients. Seven (78%) of nine invasive fungal infections (IFI) were diagnosed >100 days after NST and were associated with high mortality (78%). Most patients with IFI were also not neutropenic (100%), had received MRD graft (100%), had lymphoma (78%) and were given systemic steroids (78%); unlike CMV infection, 67% of these patients also had GVHD. On the basis of our results, we propose that NST recipients with lymphoma treated with high-dose corticosteroids for GVHD be considered for antifungal prophylaxis or pre-emptive antifungal therapy.

Antifungal therapy strategies in hematopoietic stem-cell transplant recipients: early treatment options for improving outcomes

Changes in clinical practice permit more patients to undergo hematopoietic stem-cell transplantation but also have increased the risk for invasive fungal infection (IFI) in this population. Given the difficulties in the diagnosis of fungal infection and the correlation between delays in therapy and poor outcome, earlier treatment, and prophylactic strategies are attractive options for the management of IFIs in high-risk patients. The selection of the most effective antifungal treatment strategy requires a thorough knowledge of IFI risk factors, potential causative organisms, and the safety and efficacy of appropriate antifungal agents.

Fungal brain infections

PURPOSE OF REVIEW

Fungal infections of the central nervous system, once a relatively rare occurrence, are increasingly common due to the expansion of immunocompromised populations at risk, and therefore are important to recognize early and manage appropriately.

RECENT FINDINGS

The specific infectious risk posed by novel immune-modifying therapies can, in most cases, be predicted on the basis of the immune target and medication timing. In addition, major advances in noninvasive diagnostic tests (e.g. serum beta glucan and galactomannan assays), and the recent introduction of more effective antifungal therapies, have led to a dramatic improvement in clinical outcomes.

SUMMARY

The current review provides approaches to patients with suspected central nervous system fungal infections based on host-risk factors, clinical syndromes and specific pathogens.

Minimizing the risk of recurrent or progressive invasive mold infections during stem cell transplantation or further intensive chemotherapy

The risk of recurrence or progression of prior invasive fungal infection, predominantly due to molds, is 11-33% during subsequent stem cell transplantations or myelosuppressive chemotherapy, with a high mortality. Risk factors at the time of transplant include active infection and having received <6 weeks of antifungal therapy, while after transplant prolonged neutropenia and graft-versus-host disease requiring aggressive immunosuppression are important. The use of peripheral blood stem cells has been associated with a lower risk. Minimal data are available regarding the role of preventative strategies such as surgical resection of pulmonary lesions and prophylactic granulocyte transfusions during neutropenia, the optimal duration of antifungal prophylaxis, and the appropriate monitoring strategy. This article critically evaluates these issues and provides recommendations for the secondary prophylaxis of invasive mold infections.

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

BACKGROUND

The purpose of our study was to evaluate the incidence and outcome of invasive fungal infection (IFI) among patients who underwent autologous or allogeneic hematopoietic stem cell transplantation (HSCT) at 11 Italian transplantation centers.

METHODS

This cohort-retrospective study, conducted during 1999-2003, involved HSCT patients admitted to 11 tertiary care centers or university hospitals in Italy, who developed IFIs (proven or probable).

RESULTS

Among 3228 patients who underwent HSCT (1249 allogeneic HSCT recipients and 1979 autologous HSCT recipients), IFI occurred in 121 patients (overall incidence, 3.7%). Ninety-one episodes (2.8% of all patients) were due to molds, and 30 (0.9%) were due to yeasts. Ninety-eight episodes (7.8%) occurred among the 1249 allogeneic HSCT recipients, and 23 (1.2%) occurred among the 1979 autologous HSCT recipients. The most frequent etiological agents were Aspergillus species (86 episodes) and Candida species (30 episodes). The overall mortality rate was 5.7% among allogeneic HSCT recipients and 0.4% among autologous HSCT recipients, whereas the attributable mortality rate registered in our population was 65.3% (72.4% for allogeneic HSCT recipients and 34.7% for autologous HSCT recipients). Etiology influenced the patients' outcomes: the attributable mortality rate for aspergillosis was 72.1% (77.2% and 14.3% for allogeneic and autologous HSCT recipients, respectively), and the rate for Candida IFI was 50% (57.1% and 43.8% for allogeneic and autologous HSCT recipients, respectively).

CONCLUSIONS

IFI represents a common complication for allogeneic HSCT recipients. Aspergillus species is the most frequently detected agent in these patients, and aspergillosis is characterized by a high mortality rate. Conversely, autologous HSCT recipients rarely develop aspergillosis, and the attributable mortality rate is markedly lower. Candidemia was observed less often than aspergillosis among both allogeneic and autologous HSCT recipients; furthermore, there was no difference in either the incidence of or the attributable mortality rate for candidemia among recipients of the 2 transplant types.

Non-bacterial infections in allogeneic non-myeloablative stem cell transplant recipients

Data on non-bacterial infections during allogeneic non-myeloablative hematopoietic stem cell transplantation (HSCT) are widely different. We evaluated data on 48 consecutive patients who received a conditioning regimen with fludarabine and cyclophosphamide (73%) or fludarabine and total body irradiation (27%) and then underwent allogeneic non-myeloablative HSCT. Cytomegalovirus (CMV) infection was common and occurred in 48% of patients; 3 patients developed CMV disease, and all survived. CMV reactivation was found to be common with both conditioning regimens in our patient population. Invasive aspergillosis occurred in 4 patients (8%) and 3 died. Other serious non-bacterial infections were uncommon. Review of the available literature on non-myeloablative HSCT suggests that the frequency and type of opportunistic infections vary considerably.

Increasing fungal infections in the intensive care unit

BACKGROUND

Yeasts and molds now rank among the most common pathogens in intensive care units. Whereas the incidence of Candida infections peaked in the late 1970s, aspergillosis is still increasing.

METHOD

Review of the pertinent English-language literature.

RESULTS

Most factors promoting an invasive fungal infection are difficult to avoid because they are connected directly to treatment of the underlying disease. Antifungal treatment is often commenced on an empiric basis, whereas it might be preferable to adopt a strategy based on a diagnostic procedure able to demonstrate or exclude fungal disease. Polyenes have been the drugs of choice, but voriconazole is the new standard for aspergillosis. For invasive candidiasis, fluconazole is a more convenient option, with the new echinocandins or voriconazole as alternatives.

CONCLUSIONS

The incidence of invasive fungal infection is increasing, but so too are the choices of agents for therapy. For reasons of efficacy and safety, therapy with an echinocandin or azole antifungal agent is supplanting the use of polyenes.

Clinical outcomes and direct hospital costs of reduced-intensity allogeneic transplantation in chronic myeloid leukemia

A reduced-intensity conditioning allogeneic stem cell transplantation was given to 19 patients (aged 15-59 years) in the first chronic phase and one patient in the accelerated phase with chronic myeloid leukemia (CML) after a regimen consisting of fludarabine (Flu), busulfan (Bu) and ATG Fresenius. The median follow-up was 27 months. Until day +100, no transplant-related mortality was recorded. The incidence of acute and chronic graft-versus-host disease (GvHD) was 55 and 75%, respectively. Two patients (10%) died from GvHD. Fourteen (70%) patients achieved molecular remission. Additional post-transplant intervention (donor lymphocyte infusion, imatinib) was necessary, however, in 10 patients (50% of the patients; non-achievement of stable molecular remission or later relapses). The total direct cost of the transplantation treatment for all of the patients came to 1,572,880 euro. If the patients had been treated with imatinib and followed-up with the same time period as they were following a transplantation, the direct cost of the imatinib treatment would have been 2,005,117 euro. The transplantation treatment appears to be less expensive after approximately 2 years of follow-up. Flu+Bu+ATG is a low-toxicity regimen for patients with CML. However, a close follow-up is necessary and about 50% of the patients require further therapeutic intervention.

Review of Epidemiology, Diagnosis, and Treatment of Invasive Mould Infections in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Invasive mould infections are a major cause of morbidity and mortality in hematopoietic stem cell transplant recipients (HSCT). Allogeneic HSCT recipients are at substantially higher risk than autologous HSCT recipients. Although neutropenia following the conditioning regimen remains an important risk factor for opportunistic fungal infections, most cases of invasive mould infection in allogeneic HSCT recipients occur after neutrophil recovery in the setting of potent immunosuppressive therapy for graft-versus-host disease. Invasive aspergillosis is the most common mould infection. However, there has been an increased incidence of less common non-Aspergillus moulds that include zygomycetes, Fusarium sp., and Scedosporium sp. Reflecting a key need, important advances have been made in the antifungal armamentarium. Voriconazole has become a new standard of care as primary therapy for invasive aspergillosis based on superiority over amphotericin B. There is significant interest in combination therapy for invasive aspergillosis pairing voriconazole or an amphotericin B formulation with an echinocandin. There have also been advances in novel diagnostic methods that facilitate early detection of invasive fungal infections that include galactomannan and beta-glucan antigen detection and PCR using fungal specific primers. We review the epidemiology, diagnosis, and management of invasive mould infection in HSCT, with a focus on allogeneic recipients. We also discuss options for prevention and early treatment of invasive mould infections.

Infections after allogeneic hematopoietic stem cell transplantation with a nonmyeloablative conditioning regimen

Hematopoietic cell transplantation (HCT) following nonmyeloablative conditioning (NMSCT) may be associated with a reduced risk of infection compared to standard allogeneic HCT. We retrospectively analyzed incidence and risk factors of infection in 62 patients undergoing NMSCT with low-dose TBI +/- fludarabine and postgrafting CsA and MMF. The proportion of patients with any infection was 77%, but the majority of infectious events occurred beyond day 30. Donor other than sibling, older age, early disease and male gender were significant risk factors. The incidence of bacteremia was 55% at 1 year and the number of bacteremic episodes was 0.9 per patient (0.08 before day 30). The risk of bacteremia increased with older age and the use of a donor other than an HLA-identical sibling, but not with neutropenia. The incidence of infections other than bacteremia correlated with the use of corticosteroids. The risk of CMV infection increased with high-risk CMV serology, and risk of CMV disease with high-risk CMV serology, older age, first transplantation and a diagnosis of lymphoma. In conclusion, after NMSCT, infections are not frequent in the first 30 days post transplant but careful long-term monitoring is necessary thereafter.

Management of the febrile neutropenic cancer patient: lessons from 40 years of study

Almost forty years ago the relationship between the circulating neutrophil count and the risk of pyogenic infection was established. Since that time, through the vehicle of clinical trials, much has been learnt about the etiologies, risk factors, pathogenesis, and natural history of first and subsequent febrile neutropenic episodes. Refinements to the empirical antibacterial management has reduced infection-related mortality to less than 10 percent. Algorithmic approaches to persistent fever in the setting of severe neutropenia have been developed. Circumstances wherein preventative strategies are most efficacious have been defined. Clinicians have learned that neutropenic patients comprise a heterogeneous population that does not encounter the same risks for infection-related morbidity and mortality. Tailored stratified approaches to management of the febrile neutropenic patient have been developed that are safe and cost-effective.

Aspergillus fumigatus: Growth and virulence

Aspergillus fumigatus is a ubiquitous fungus that plays an important role in carbon and nitrogen recycling in nature. Because A. fumigatus is thermotolerant, it is a predominant organism during the high-temperature phase of the compost cycle. The ability to grow at elevated temperatures and to utilize numerous varied sources of both carbon and nitrogen to support its growth have made A. fumigatus an important opportunistic pathogen of humans as well as a vital part of the nutrient-recycling ecosystem. Data correlating the growth rate and germination potential of A. fumigatus at 37 degrees C with its pathogenic potential suggest that these are related, both when viewed from a population standpoint and when analyzed on a single gene basis. Nutritional versatility has been cited as an important contributor to virulence as well. Indeed, perturbation of pathways involved with nitrogen or carbon sensing has been shown to reduce virulence in animal models, even when in vitro growth rates have not been altered. Therefore, the remarkable ability of A. fumigatus to grow efficiently under a variety of environmental conditions and to utilize a wide variety of substrates to meet its nutritional needs contributes to its role as the predominant mould pathogen of immunocompromised patients.

Development of a DNA microarray for detection and identification of fungal pathogens involved in invasive mycoses

Invasive fungal infections have emerged as a major cause of morbidity and mortality in immunocompromised patients. Conventional identification of pathogenic fungi in clinical microbiology laboratories is time-consuming and, therefore, often imperfect for the early initiation of an adequate antifungal therapy. We developed a diagnostic microarray for the rapid and simultaneous identification of the 12 most common pathogenic Candida and Aspergillus species. Oligonucleotide probes were designed by exploiting the sequence variations of the internal transcribed spacer (ITS) regions of the rRNA gene cassette to identify Candida albicans, Candida dubliniensis, Candida krusei, Candida glabrata, Candida tropicalis, Candida parapsilosis, Candida guilliermondii, Candida lusitaniae, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, and Aspergillus terreus. By using universal fungal primers (ITS 1 and ITS 4) directed toward conserved regions of the 18S and 28S rRNA genes, respectively, the fungal ITS target regions could be simultaneously amplified and fluorescently labeled. To establish the system, 12 pre-characterized fungal strains were analyzed; and the method was validated by using 21 clinical isolates as blinded samples. As the microarray was able to detect and clearly identify the fungal pathogens within 4 h after DNA extraction, this system offers an interesting potential for clinical microbiology laboratories.

Incidence of invasive aspergillosis following hematopoietic stem cell and solid organ transplantation: interim results of a prospective multicenter surveillance program

The incidence of invasive aspergillosis was estimated among 4621 hematopoietic stem cell transplants (HSCT) and 4110 solid organ transplants (SOT) at 19 sites dispersed throughout the United States, during a 22 month period from 1 March 2001 through 31 December 2002. Cases were identified using the consensus definitions for proven and probable infection developed by the Invasive Fungal Infections Cooperative Group of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group of the National Institute of Allergy and Infectious Diseases. The cumulative incidence (CI) of aspergillosis was calculated for the first episode of the infection that occurred within the specified time period after transplantation. To obtain an aggregate CI for each type of transplant, data from participating sites were weighted according to the proportion of transplants followed-up for specified time periods (four and 12 months for HSCT; six and 12 months for SOT). The aggregate CI of aspergillosis at 12 months was 0.5% after autologous HSCT, 2.3% after allogeneic HSCT from an HLA-matched related donor, 3.2% after transplantation from an HLA-mismatched related donor, and 3.9% after transplantation from an unrelated donor. The aggregate CI at 12 months was similar following myeloablative or non-myeloablative conditioning before allogeneic HSCT (3.1 vs. 3.3%). After HSCT, mortality at 3 months following diagnosis of aspergillosis ranged from 53.8% of autologous transplants to 84.6% of unrelated-donor transplants. The aggregate CI of aspergillosis at 12 months was 2.4% after lung transplantation, 0.8% after heart transplantation, 0.3% after liver transplantation, and 0.1% after kidney transplantation. After SOT, mortality at three months after diagnosis of aspergillosis ranged from 20% for lung transplants to 66.7% for heart and kidney transplants. The Aspergillus spp. associated with infections after HSCT included A. fumigatus (56%), A. flavus (18.7%), A. terreus (16%), A. niger (8%), and A. versicolor (1.3%). Those associated with infections after SOT included A. fumigatus (76.4%), A. flavus (11.8%), and A. terreus (11.8%). In conclusion, we found that invasive aspergillosis is an uncommon complication of HSCT and SOT, but one that continues to be associated with poor outcomes. Our CI figures are lower compared to those of previous reports. The reasons for this are unclear, but may be related to changes in transplantation practices, diagnostic methods, and supportive care.

The influence of the conditions of hematopoietic cell transplantation on infectious complications

PURPOSE OF REVIEW

The multitude of factors that influence the risk of infection after hematopoietic cell transplantation has been further complicated by the rapid evolution of this therapy in the past 5 years. The degree to which functional immune reconstitution has been achieved reflects the equilibrium reached by the immune systems of the recipient and donor in the context of host non-hematopoietic tissue. Thus immunomodulatory influences on the recipient and the transplanted graft, both before and after hematopoietic cell transplantation, have a profound influence on the incidence and severity of infection. This review of the recent literature contributes to our understanding of how the conditions of hematopoietic cell transplantation influence the timing and nature of infectious complications.

RECENT FINDINGS

The main themes of published primary research from 2004 to the present focus on non-myeloablative conditioning regimens and their effects on immune reconstitution after hematopoietic cell transplantation.

SUMMARY

A plethora of clinical trials are ongoing, focused on the outcome after conditioning regimens designed to result in less regimen-related toxicity while preserving or enhancing the graft-versus-tumor effect. Given the infancy of these new approaches, it is not possible to make definitive statements regarding the relative risk of serious infection with each therapy. It is clear that a reduction in regimen-related non-infectious complications or mortality does not necessarily ensure a reduction in clinically significant infections. Improvements in early diagnostic and therapeutic options for these infections now bring us to an era of understanding pathogens as probes of the functional reconstitution of immunity.

Cause of death after allogeneic haematopoietic stem cell transplantation (HSCT) in early leukaemias: an EBMT analysis of lethal infectious complications and changes over calendar time

We analysed a large homogeneous group of 14,403 patients transplanted for early leukaemia from an HLA-identical sibling and reported to the EBMT in four time cohorts: 1980-1989 (24%), 1990-1994 (26%), 1995-1998 (30%) and 1999-2001 (20%). We focused on death from infection. End points were survival, death from relapse and transplant-related mortality (TRM), which was subdivided into death from graft-versus-host disease (GvHD) (1315 patients; 25% of deaths), infection (597 patients; 11% of deaths) or 'other' causes (1875 patients; 34% of deaths). Survival increased from 52% at 5 years in the first to 62% in the third cohort (P<0.05) and TRM decreased from 36 to 26% (P<0.05) due to a reduction in death from infection (P<0.001). GvHD, 'other' causes and relapse did not improve. The relative proportions of bacteria (217 patients; 36%), viruses (183 patients; 31%), fungi (166 patients; 28%) or parasites (32 patients; 5%) as cause of infectious death (cumulative incidence of death at 5 years 1.8, 1.6, 1.4 and > or = 0.3%, respectively) and median time to death from infections (3 months (range 0-158 months)) did not change. Death from infections has been reduced significantly, but it still represents an ongoing risk after HSCT and draws attention to the time beyond the initial period of neutropenia.

Peripheral T-cell expansion and low infection rate after reduced-intensity conditioning and allogeneic blood stem cell transplantation

Peripheral blood stem cell transplantation after reduced-intensity conditioning (RIC-PBSCT) regimen is an alternative to conventional regimens with less immediate toxicity. Since immune recovery is of crucial importance for the control of infections, we retrospectively studied the recovery of T-, B- and NK cell subsets in 20 consecutive patients undergoing RIC-PBSCT. We also studied the thymic output using T-cell receptor excision circle assay. Engraftment was rapid and few infectious complications were seen: three early (before 2.5 months) cases of asymptomatic cytomegalovirus reactivation, two late Gram-negative bacterial infections and no fungal infection. While CD4+ T-cell reconstitution was slow, CD8+ T-cell counts were close to normal values at 4 months. Median CD19+ B-cell counts reached normal values at 11 months. Rapid CD56+ NK cell reconstitution was noticed as early as 1.5 months. Low T-cell receptor excision circle numbers and preponderance of memory-type subsets among T cells further suggested that CD8+ T-cell reconstitution resulted predominantly from peripheral expansion and that thymic-dependent reconstitution was severely impaired. In conclusion, large peripheral T-cell expansion may compensate for late thymic-dependent lymphopoiesis, and may, with other factors such as NK and B-cell reconstitution and careful antiinfectious prophylaxis, help limit the incidence of severe infections after RIC-PBSCT.

Isolation in the allogeneic transplant environment: how protective is it?

Aggressive infection control measures that include isolating patients within protective hospital environments have become a standard practice during allogeneic stem cell transplantation. A wide range of interventions includes the management of ventilation systems, BMT unit construction and cleaning, isolation and barrier precautions, interactions with health-care workers and visitors, skin and oral care, infection surveillance, and the prevention of specific nosocomial and seasonal infections. However, many of these practices have not been definitively proven to provide patients the intended benefit of decreased infection rates or improved survival. Furthermore, each intervention comes with a financial and social cost. With institutional cost containment efforts and recent trials suggesting that patients may be safely cared for in the outpatient environment after allogeneic transplantation, many widely held practices in managing the transplant environment are being reconsidered. With changing practices, transplant teams are encouraged to review local patterns of infections and associated complications and communicate regularly with infection control committees for guidance on the evolution of isolation needs for the immunosuppressed patient.