Risk factors for invasive fungal infections in haematopoietic stem cell transplantation

Risk factors for invasive fungal infections after haematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

Invasive fungal infections (IFIs) are common infectious complications after haematopoietic stem cell transplantation (HSCT), seriously threatening the survival of patients.

OBJECTIVES

This systematic review aimed to investigate risk factors associated with IFIs following HSCT.

METHODS

Two authors independently conducted the selection of studies and extraction of data. Risk factors for IFIs, invasive aspergillosis or invasive mould infections and invasive candida infection after HSCT were compiled separately by meta-analysis using RevMan 5.4 and R language 4.1.2.

DATA SOURCES

Pubmed, EMBASE, Web of Science, and the Cochrane Library until April 2023.

STUDY ELIGIBILITY CRITERIA

Case-control or cohort studies that assessed risk factors for IFIs among HSCT recipients were included.

PARTICIPANTS

Patients experiencing HSCT.

TEST/S

None.

REFERENCE STANDARD

The IFIs were defined according to the European Organisation for Research and Treatment of Cancer/Mycosis Study Group (EORTC/MSG) criteria, or a similar definition.

ASSESSMENT OF RISK OF BIAS

A modified version of the Newcastle-Ottawa Scale was used.

METHODS OF DATA SYNTHESIS

A random-effects model with the Mantel-Haenszel method was used to pool results from primary studies.

RESULTS

Out of 1637 studies screened, 51 studies involving 109 155 patients were included, with 45 studies providing adequate data for meta-analysis. Identified risk factors for IFIs included prolonged neutropenia, intensified therapy for graft-versus-host disease (GVHD), previous transplantation, previous proven or probable IFI, acute GVHD ≥ grade II, extensive or severe chronic GVHD, use of anti-thymocyte globulin during transplantation, haploidentical transplantation, high-dose glucocorticoids, Epstein-Barr virus infection, cytomegalovirus infection or reactivation, and lower albumin. Conversely, antifungal prophylaxis emerged as the sole preventive factor. For invasive aspergillosis or invasive mould infections, the top risk factors were extensive or severe chronic GVHD, respiratory viral infection, high-dose glucocorticoids, acute GVHD ≥ grade II, and human leukocyte antigen mismatch. Cord blood transplantation was the sole significant risk factor for invasive candidiasis. However, there was likely a high degree of interdependence among various risk factors.

DISCUSSION

This meta-analysis provides a thorough review of risk factors for IFIs infection after HSCT. The achieved insights can aid in stratifying patients who are at an elevated risk of IFIs and promoting antifungal preventive strategies.

Antifungal Prophylaxis with Posaconazole versus Fluconazole in Children with Neutropenia Following Allogeneic Hematopoietic Stem Cell Transplantation: Single Center Experience

Background

Invasive fungal diseases (IFDs) are common and contribute to mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). The relative efficacies of posaconazole (POS) and fluconazole (FLU) as primary antifungal prophylaxes are uncertain.

Methods

A retrospective study was performed on children treated with allogeneic HSCT who received POS or FLU during the early neutropenic period. The efficacies, safety, and tolerabilities of the prophylaxes were compared.

Results

Data on 78 HSCT recipients were analyzed. Most had thalassemia (58%). Pre-engraftment, POS and FLU were administered to 41 and 37 cases, respectively. There were no proven cases of IFD. However, 2 POS cases and 1 FLU case had probable IFDs. The IFD incidences of the POS (5%) and FLU (3%) groups demonstrated no statistical difference (p = 0.620). Of the 75 surviving cases receiving FLU post-engraftment (including 39 cases previously given POS), 3 had proven IFDs whereas 3 had probable IFDs (total, 6 [8%]) within 1 year post-HSCT. No cases discontinued the prophylaxes due to drug intolerance. The common adverse events with POS and FLU were not significantly different. Only 19% of the patients achieved the therapeutic POS level, with a starting dose of 4 mg/kg thrice daily.

Conclusion

POS and FLU demonstrate comparable levels of effectiveness, safety, and tolerability as IFD prophylaxes for neutropenic children treated with allogeneic HSCT. Determination of the optimum POS dose and duration requires larger studies.

Invasive Fungal Disease Among Pediatric and Adolescent Patients Undergoing Itraconazole Prophylaxis After Hematopoietic Stem Cell Transplantation

BACKGROUND

Invasive fungal disease (IFD) is a major cause of morbidity and mortality in patients after hematopoietic stem cell transplantation (HSCT). Itraconazole has been used for prevention of IFD, but data related to incidence and associated factors of IFD in pediatric and adolescent patients on itraconazole prophylaxis remain scarce.

OBJECTIVES

To identify incidence and risk factors associated with IFD among pediatric and adolescent patients receiving itraconazole prophylaxis after HSCT.

METHODS

Patients younger than 21 years who received itraconazole prophylaxis after HSCT from January 2007 to December 2016 were retrospectively enrolled. Incidence of IFD within 1 year and associated factors were analyzed.

RESULTS

All patients received itraconazole during the pre-engraftment period. Of 170 patients, 29 had IFD, with an incidence of 17.1% at 1 year. IFD at 1 year was significantly associated with increased mortality. Of 29 patients with IFD, only 9 developed IFD while on itraconazole prophylaxis (5.3%), all of whom had invasive pulmonary aspergillosis. No invasive candidiasis occurred during itraconazole prophylaxis. Prolonged neutropenia (hazard ratio [HR] = 1.08; 95% confidence interval [CI], 1.02-1.13), graft-versus-host disease within 100 days after transplantation (HR = 3.17; 95% CI, 1.17-8.57), and using etoposide in preconditioning regimens (HR = 21.60; 95% CI, 2.44-190.95) were significantly associated with IFD at 1 year. No patients had to discontinue itraconazole because of its adverse effects.

CONCLUSIONS

Itraconazole proffered good efficacy for prevention of candidiasis during the pre-engraftment period. Most IFD episodes occurred after the engraftment period when itraconazole had been discontinued. During this period, patients with risk factors require appropriate fungal prophylaxis.

The FOSSIL Study: FLAG or standard 7+3 induction therapy in secondary acute myeloid leukemia

Patients with secondary acute myeloid leukemia (sAML) have poor outcomes, with CR/CRi rates of 25-35% with standard 7 + 3 induction chemotherapy, while single center non-comparative analyses suggest promising outcomes with FLAG. We conducted a single-center, retrospective cohort study assessing outcomes in treatment-naïve patients with sAML treated with fludarabine, high-dose cytarabine, and granulocyte colony-stimulating factor (FLAG, n = 40) compared with 7 + 3 (n = 66). Median patient age was 63 years (range: 27-82) in the FLAG group and 60 years (range: 21-76) in the 7 + 3 group (P = 0.968). Patients treated with FLAG achieved higher overall response rates (CR + CRi + MLFS) compared to 7 + 3 (70% vs. 48%, P = 0.043). FLAG was well tolerated, with only one induction death (30-day mortality rate, 3% vs. 8%, P = 0.405) and no cases of cerebellar toxicity. Duration of neutropenia was significantly shorter with FLAG (median 16 vs. 23 days, P < 0.001). Half of the FLAG-treated patients proceeded to consolidative therapy compared with only 27% of those who received 7 + 3 (P = 0.022). Overall survival was comparable between groups (8.5 mos, FLAG vs. 9.1 mos, 7 + 3; P = 0.798). Thus, FLAG may represent a low-cost treatment strategy in sAML that produces higher response rates and promising survival outcomes with minimal treatment-related toxicity. Further studies are required to prospectively compare FLAG to the newly FDA-approved CPX-351 in sAML.

Outcomes of previously untreated elderly patients with AML: a propensity score-matched comparison of clofarabine vs. FLAG

The 5-year overall survival (OS) in patients ≥ 60 years old with acute myeloid leukemia (AML) remains < 10%. Clofarabine-based induction (CLO) provides an alternative to low-intensity therapy (LIT) and palliative care for this population, but supporting data are conflicted. Recently, our institution adopted the FLAG regimen (fludarabine, cytarabine, and granulocyte colony-stimulating factor) based on data reporting similar outcomes to CLO in elderly patients with AML unable to tolerate anthracycline-based induction. We retrospectively analyzed the efficacy and safety of patients ≥ 60 years old with AML treated with FLAG or CLO over the past 10 years. We performed a propensity score match that provided 32 patients in each group. Patients treated with FLAG had a higher CR/CRi rate (65.6 vs. 37.5%, P = 0.045) and OS (7.9 vs. 2.8 months, P = 0.085) compared to CLO. Furthermore, FLAG was better tolerated with significantly less grade 3/4 toxicities and a shorter duration of neutropenia (18.5 vs. 30 days, P = 0.002). Finally, we performed a cost analysis that estimated savings to be $30,000-45,000 per induction with FLAG. Our study supports the use of FLAG both financially and as an effective, well-tolerated high-dose treatment regimen for elderly patients with AML. No cases of cerebellar neurotoxicity occurred.

A Quasi-Experimental Study Analyzing the Effectiveness of Portable High-Efficiency Particulate Absorption Filters in Preventing Infections in Hematology Patients during Construction

OBJECTIVE

The increased risk of infection for patients caused by construction and renovation near hematology inpatient clinics is a major concern. The use of high-efficiency particulate absorption (HEPA) filters can reduce the risk of infection. However, there is no standard protocol indicating the use of HEPA filters for patients with hematological malignancies, except for those who have undergone allogeneic hematopoietic stem cell transplantation. This quasi-experimental study was designed to measure the efficacy of HEPA filters in preventing infections during construction.

MATERIALS AND METHODS

Portable HEPA filters were placed in the rooms of patients undergoing treatment for hematological malignancies because of large-scale construction taking place near the hematology clinic. The rates of infection during the 6 months before and after the installation of the portable HEPA filters were compared. A total of 413 patients were treated during this 1-year period.

RESULTS

There were no significant differences in the antifungal prophylaxis and treatment regimens between the groups. The rates of infections, clinically documented infections, and invasive fungal infections decreased in all of the patients following the installation of the HEPA filters. When analyzed separately, the rates of invasive fungal infections were similar before and after the installation of HEPA filters in patients who had no neutropenia or long neutropenia duration. HEPA filters were significantly protective against infection when installed in the rooms of patients with acute lymphocytic leukemia, patients who were undergoing consolidation treatment, and patients who were neutropenic for 1-14 days.

CONCLUSION

Despite the advent of construction and the summer season, during which environmental Aspergillus contamination is more prevalent, no patient or patient subgroup experienced an increase in fungal infections following the installation of HEPA filters. The protective effect of HEPA filters against infection was more pronounced in patients with acute lymphocytic leukemia, patients undergoing consolidation therapy, and patients with moderate neutropenia.

Risks and Epidemiology of Infections After Hematopoietic Stem Cell Transplantation

Infections following HCT are frequently related to risk factors caused by the procedure itself. Neutropenia and mucositis predispose to bacterial infections. Prolonged neutropenia increases the likelihood of invasive fungal infection. GVHD and its treatment create the most important easily identifiable risk period for a variety of infectious complications, particularly mold infections. Profound, prolonged T cell immunodeficiency, present after T cell-depleted or cord blood transplants, is the main risk factor for viral problems like disseminated adenovirus disease or EBV-related posttransplant lymphoproliferative disorder.

Experience with anidulafungin in patients with allogeneic hematopoietic stem cell transplantation and graft-versus-host disease

BACKGROUND

It is well known that both acute and chronic graft-versus-host disease (GVHD) are associated with invasive fungal disease (IFD). Because the galactomannan antigen diagnostic test has low specificity and sensitivity outside of the neutropenic period, many institutions use posaconazole or voriconazole for IFD prophylaxis during GVHD treatment. Moreover, several factors, mainly hepatic impairment, can limit the use of extended spectrum azoles, both in prophylaxis or treatment.

METHODS

We retrospectively analyzed 25 patients with allogeneic hematopoietic stem cell transplantation (HSCT) and GVHD - grade III-IV acute GHVD (n = 15), progressive chronic GVHD (n = 7), and "overlap" GVHD (n = 3) - who received intravenous anidulafungin (200 mg on day 1, followed by 100 mg once daily). If necessary, anidulafungin treatment was followed by oral administration of 200 mg voriconazole twice a day or 200 mg posaconazole 3 times daily until patients were considered not at risk for IFD.

RESULTS

Twenty-one patients (85%) received anidulafungin as prophylaxis and 5 patients (15%) received it as treatment. Median duration of intravenous anidulafungin administration was 8 days (range 6-17). Seven patients (28%) presented mild adverse effects, with no significant interactions with calcineurin inhibitors. Sequentially, 4 patients received voriconazole and 6 posaconazole. Two patients (8%) developed IFD after anidulafungin withdrawal: 1 with Candida albicans and the other with Mucor, 8 and 5 days after withdrawal, respectively.

CONCLUSIONS

Our results are of interest owing to the absence of data in the literature on anidulafungin use in HSCT patients with GVHD, and suggest that anidulafungin, because of its spectrum, pharmacological profile, low toxicity, and absence of interactions with immunosuppressants, could be a drug of choice in this setting.

Risk factors for candida infection of the genital tract in the tropics

OBJECTIVE

To investigate the risk factors associated with candida infection of the genital tract in the tropics.

METHODS

We performed questionnaire survey and experiments at the Hainan branch of General Hospital of People's Liberation Army, Hainan General Hospital and Sanya Maternity and Child Health Care Hospital in 2013. Controls were without Candida infection of genital tract, and cases had from Candida infection.

RESULTS

We recruited 689 cases and 652 controls. The average age of cases with Candida infection of the genital tract was higher than that of controls. In the multivariate modeling, marriage (adjusted odds ratio: 2.49, 95% confidential interval: 1.09-5.67) and vaginal lavage (adjusted odds ratio: 4.41, 95% confidential interval: 1.13-5.14) were significantly associated with Candida infection of genital tract in tropics.

CONCLUSION

Candida infection was related with age. Marriage and Vaginal lavage were significant risk factors. Attention should be paid to health education for the prevention of these infections.

Posaconazole concentrations after allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Posaconazole is recommended for prophylaxis of fungal infections and for salvage therapy of invasive aspergillosis after stem cell transplantation. An impact of drug concentration on efficacy has been suggested.

METHODS

In this study, we investigated serum levels of posaconazole in 262 samples from 64 allogeneic stem cell recipients.

RESULTS

A high degree of interindividual variation was observed. Concentrations were significantly higher for male patients compared with female patients (median 570 and 426 ng/mL, respectively), but no differences for age or dosing groups (400 mg twice daily [BID] or 200 mg three times a day) could be detected. The predictive value of the first determined posaconazole concentration in steady state and of a concentration >500 and 700 ng/mL at any time was evaluated, compared with patients with a first level <300 ng/mL (mean 10.3%, median 0%).

CONCLUSION

In patients receiving 400 mg BID, the mean rate of serum levels >500 ng/mL in subsequent determinations was higher, if the first serum concentration during steady state was >300 ng/mL (mean 61.1%, median 60%, P = 0.002) or >500 ng/mL (67.7%, median 75%, P = 0.002). Based on this retrospective analysis, a posaconazole serum concentration >500 ng/mL at any time point might also help to predict sufficient drug concentrations.

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.

Aspergillus galactomannan antigen assay and invasive aspergillosis in pediatric cancer patients and hematopoietic stem cell transplant recipients

BACKGROUND

Invasive aspergillosis (IA) is a major cause of morbidity and mortality in immunocompromised children. We investigated the usefulness of an Aspergillus galactomannan (GM) antigen assay as a diagnostic tool for IA in pediatric cancer patients and hematopoietic cell transplantation (HCT) recipients.

PROCEDURE

The GM antigen assay results were analyzed in 749 blood samples from 99 patients. A GM index (GMI) greater than or equal to 0.5 on at least two separate occasions was considered positive. A review of the clinical data was performed for subjects with proven or probable IA.

RESULTS

Twenty-one of 23 patients with proven or probable IA had positive GM antigen test results (91.3% sensitivity, 95% CI 71.9-98.9; 81.7% specificity, 95% CI 69.6-90.5; P < 0.0001). The false-positive rate was 18.3%. Being younger than 3 years of age, having a solid tumor, and receiving HCT within 4 weeks of the test were statistically significant factors for causing false-positive results (P < 0.05). Among the 23 patients with IA (six proven, 17 probable), 16 (69.6%) had hematological malignancies, five (22.7%) had solid tumors, and two (8.7%) had primary immunodeficiency. Nineteen patients (82.6%) received HCT. The most common clinical site of IA was the lungs (91.3%), and consolidation was the most frequent finding in chest CT scans (36.8%). The mortality at 12 weeks was 43.5%.

CONCLUSIONS

Having a positive GM assay at least twice is useful in diagnosing IA in pediatric patients with cancer and HCT recipients.

Prevalence of biofilm formation in clinical isolates of Candida species causing bloodstream infection

Candida species are the fourth most common cause of nosocomial invasive infections. Biofilm formation is recognised as one virulence factor of Candida species. A total of 243 Candida albicans, 81 C. glabrata, 33 C. parapsilosis, 14 C. dubliniensis, 8 C. tropicalis, 8 C. lusitaniae, 5 C. krusei and 1 C. pelliculosa isolates causing bloodstream infections were evaluated for biofilm formation. The biofilm formed on silicone elastomer preincubated with human serum was quantified by estimation of the metabolic activity through XTT assay and visualised by light and scanning electron microscopy. Forty per cent of the C. albicans isolates formed biofilm compared to 88.7% of the non-albicans Candida isolates (P < 0.0001). Among non-albicans Candida spp., biofilm formation was most commonly observed in C. tropicalis and C. lusitaniae (100%), followed by C. glabrata (95%), C. dubliniensis (85.7%) and C. parapsilosis (66.7%). A quantitative correlation was observed between the amount of biofilm observed microscopically, and that determined by metabolic activity measurements. The biofilms of all Candida species were composed of basal yeast cells with the exception of C. parapsilosis which produced biofilms consisting of pseudohyphae and aggregated yeast cells. These results suggest that biofilm formation as a virulence factor might have a higher significance for non-albicans Candida species than for C. albicans.

Dry powder insufflation of crystalline and amorphous voriconazole formulations produced by thin film freezing to mice

Attention has begun to focus on the pulmonary delivery of antifungal agents for invasive fungal infections as inhalation of the fungal spores is often the initial step in the pathogenesis of many of these infections, including invasive pulmonary aspergillosis (IPA). IPA in immunocompromised patients has high mortality rates despite current systemic (oral or intravenous) therapies. In this study, particulate voriconazole (VRC) formulations were designed with suitable properties for inhalation using thin film freezing (TFF), a particle engineering process capable of producing low-density porous aggregate particles. Nanostructured amorphous morphology of VRC was less favorable in vitro and in vivo than microstructured crystalline morphology, despite being a poorly water-soluble compound. Using a Handihaler dry powder inhaler (DPI), microstructured crystalline TFF-VRC and nanostructured amorphous TFF-VRC-PVP K25 (1:3) had fine particle fractions of 37.8% and 32.4% and mass median aerodynamic diameters of 4.2 and 5.2 μm, respectively. Single dose 24-h pharmacokinetic studies were conducted in ICR mice. AUC(0-24h) in the lung tissue and plasma was 452.6 μg h/g wet lung weight and 38.4 μg h/mL, respectively, following a 10mg/kg insufflated dose of TFF-VRC directly into the lungs of the mice, while AUC(0-24 h) in the lung tissue and plasma was 232.1 μg h/g wet lung weight and 18.6 μg h/mL, respectively, following a 10mg/kg insufflated dose of TFF-VRC-PVP K25 (1:3). High concentrations of VRC in lung tissue coupled with clinically relevant plasma concentrations suggest that pulmonary delivery of microstructured crystalline VRC could potentially be a beneficial strategy for administration of VRC to patients with invasive pulmonary fungal infections.

Dexamethasone palmitate successfully attenuates hemophagocytic syndrome after allogeneic stem cell transplantation: macrophage-targeted steroid therapy

Hemophagocytic syndrome (HPS) induced by uncontrolled macrophage activation and subsequent graft failure is a frequent and prominent complication after allogeneic stem cell transplantation (allo-SCT), a cause of severe morbidity and death, and a therapeutic challenge. Liposome-incorporated dexamethasone, dexamethasone palmitate (DP), shows greater efficacy against macrophages as compared to dexamethasone sodium phosphate (DSP). Based on our findings that DP achieves significantly larger decrease than DSP on the viability of primary human macrophages compared in vitro, we tested the effects of DP in patients with HPS. A decrease in number of macrophages in the bone marrow and prevention of engraftment failure were observed in all patients without any severe complications. In conclusion, these data provide a rationale for testing DP as a first-line treatment for patients with HPS after allo-SCT.

Immune response to Aspergillus fumigatus in compromised hosts: from bedside to bench

The relevance of studies aimed at understanding host immune response against Aspergillus fumigatus takes on much significance given that all patients with invasive aspergillosis are invariably immunocompromised. This article attempts to correlate relevant findings from recent experimental studies to clinical observations made by the physician at the bedside. It is hoped that the increased understanding of host-fungus immune interaction may pave the way for the development of new management strategies against this difficult-to-treat fungal disease.

Immunotherapy against invasive fungal diseases in stem cell transplant recipients

Despite the availability of new antifungal compounds, morbidity and mortality of invasive fungal disease in allogeneic hematopoietic stem cell recipients are still unacceptably high. Over the past decade, one could witness an exciting improvement of the understanding of the molecular pathogenesis and of the complexity of host antifungal immune responses. This, in turn, provides critical information to augment host immunity against fungal pathogens. Strategies for enhancing the immune system include the administration of effector and regulatory cells (e.g., granulocytes, antigen-specific T cells, dendritic cells) as well as the administration of recombinant cytokines, interferons and growth factors (e.g., interferon-γ, keratinocyte growth factor, granulocyte- and granulocyte-macrophage colony stimulating factor). One has to recognize at the same time, however, that data of in vitro assays and animal models cannot necessarily be transferred into the clinical setting. In addition, meaningful clinical trials in allogeneic stem cell recipients suffering from invasive fungal disease require sufficiently large and homogenous cohorts of patients and can only be performed in international collaboration, but may ultimately improve the outcome of allogeneic transplant recipients with invasive fungal disease.

Aspergillus fumigatus: contours of an opportunistic human pathogen

Aspergillus fumigatus is currently the major air-borne fungal pathogen. It is able to cause several forms of disease in humans of which invasive aspergillosis is the most severe. The high mortality rate of this disease prompts increased efforts to disclose the basic principles of A. fumigatus pathogenicity. According to our current knowledge, A. fumigatus lacks sophisticated virulence traits; it is nevertheless able to establish infection due to its robustness and ability to adapt to a wide range of environmental conditions. This review focuses on two crucial aspects of invasive aspergillosis: (i) properties of A. fumigatus that are relevant during infection and may distinguish it from non-pathogenic Aspergillus species and (ii) interactions of the pathogen with the innate and adaptive immune systems.

Invasive aspergillosis in pediatric patients

This case-based review examines the growing literature on critical issues related to the epidemiology, diagnosis, and treatment of pediatric invasive aspergillosis. Immunocompromised children are at heightened risk for invasive aspergillosis. Children at highest risk include those with new-onset or relapsed hematologic malignancy and recipients of allogeneic stem cell transplants. Additional risk factors in stem cell transplant recipients include impaired lymphocyte engraftment and graft-versus-host disease. Pediatric invasive aspergillosis is associated with a high mortality rate (generally >50%) and requires prompt diagnosis and treatment to prevent dissemination and death. Tools available for diagnosis include radiologic examinations (primarily computed tomography), the galactomannan assay, bronchoalveolar lavage, and tissue biopsy. Age-related differences in computed tomography and galactomannan assay results have been suggested. Recommended primary therapy for pediatric invasive aspergillosis is voriconazole (7 mg/kg IV q12 hours). Currently approved alternative therapies include liposomal amphotericin B, amphotericin B lipid complex, and caspofungin. Posaconazole and itraconazole are also possibilities, but there is no established pediatric dose for posaconazole, and itraconazole dosing is difficult in children. In patients who do not benefit from initial antifungal therapy, options include switching to another agent with a different mechanism of action or combination therapy. Further research is required to better establish optimal approaches to the management of pediatric patients with invasive aspergillosis recalcitrant to initial primary therapy.

Advances in the treatment of neutropenia

PURPOSE OF REVIEW

The present review updates treatment of neutropenia from articles published from January 2008 through April 2009.

RECENT FINDINGS

Chemotherapy-induced neutropenia occurs most commonly in the first cycle of treatment. Older patients, patients with multiple comorbidities, and those receiving more myelotoxic drugs are prone to develop neutropenia and its complications. Current guidelines recommend the prophylactic use of the myeloid growth factors for the first cycle of chemotherapy for patients with more than a 20% risk of febrile neutropenia. Meta analysis from randomized trials shows that granulocyte colony-stimulating factor prophylaxis is associated with patients receiving more intensive chemotherapy, having better survival, but also having a higher risk of secondary acute myeloid leukemia. Antibiotics are standard treatment of febrile neutropenia and are increasingly used for prophylaxis in 'low-risk' patients.

SUMMARY

The myeloid growth factor granulocyte colony-stimulating factor has radically changed our approach to the prevention of febrile neutropenia. Antibiotics remain the mainstay of treatment of febrile neutropenia.

Fungal metabolism in host niches

Invasive fungal infections of immunocompromised patients cause major problems in modern medicine and only a limited number of effective antifungals are available, making the identification of new drug targets a priority. The inhibition of primary metabolism represents a promising therapeutic strategy, but a better understanding of the metabolic processes during pathogenesis is required. Infection, invasion and maintenance within a host are very dynamic events and fungal metabolism has to adapt to these changes. Glycolysis, gluconeogenesis and starvation all contribute to successful host colonisation, but the temporal and spatial resolution of their specific importance is poorly understood. Knowledge about the metabolic requirements of pathogenic fungi during infection could lead to the identification of new classes of antifungals, which allow the treatment of otherwise life-threatening infections.