Aspergillus fumigatus suppresses the human cellular immune response via gliotoxin-mediated apoptosis of monocytes

Aspergillus fumigatus (AF) is a ubiquitous mold and is the most common cause of invasive aspergillosis, an important source of morbidity and mortality in immunocompromised hosts. Using cytokine flow cytometry, we assessed the magnitude of functional CD4+ and CD8+ T-cell responses following stimulation with Aspergillus antigens. Relative to those seen with cytomegalovirus (CMV) or superantigen stimulation, responses to Aspergillus antigens were near background levels. Subsequently, we confirmed that gliotoxin, the most abundant mycotoxin produced by AF, was able to suppress functional T-cell responses following CMV or staphylococcal enterotoxin B (SEB) stimulation. Additional studies demonstrated that crude AF filtrates and purified gliotoxin inhibited antigen-presenting cell function and induced the preferential death of monocytes, leading to a marked decrease in the monocyte-lymphocyte ratio. Analysis of caspase-3 activation confirmed that gliotoxin preferentially induced apoptosis of monocytes; similar effects were observed in CD83+ monocyte-derived dendritic cells. Importantly, the physiologic effects of gliotoxin in vitro were observed below concentrations recently observed in the serum of patients with invasive aspergillosis. These studies suggest that the production of gliotoxin by AF may constitute an important immunoevasive mechanism that is mediated by direct effects on antigen-presenting cells and both direct and indirect effects on T cells.

Prise en charge diagnostique et thérapeutique des infections à Aspergillus sp. chez le patient immunodéprimé. Recommandations du CHRU de Lille — version 4 — novembre 2004

Invasive aspergillosis is a severe complication in immunocompromised patients. The arrival of new antifungal agents motivated the redaction of guidelines, regularly updated, by a Lille University hospital multidisciplinary task force. These guidelines assess diagnostic and therapeutic issues. The main recommended diagnosis tool is the chest CT scan, ordered at the smallest suspicion and, also, measure of the blood and broncho alveolar lavage fluid galactomannan. Treatment guidelines assess prophylaxis, empirical and documented therapy. Primary prophylaxis is warranted in only two cases, pulmonary graft or stem cell transplant in patients with chronic GVH and receiving corticosteroids. Empirical therapy should use one of the available amphotericin B formulations, chosen according to the patient history. Caspofungin is another choice. Documented therapy, depending on presentation, can be a single drug or a combination. First line therapy for single drug is i.v. voriconazole. Lipid formulations of amphotericin B are another choice. A combination therapy can be used as a first line treatment, for multiple lesions, or as salvage therapy. It must include caspofungin, associated with liposomal amphotericin B or voriconazole. A tight cooperation with thoracic surgeons is recommended.

TLRs govern neutrophil activity in aspergillosis

Polymorphonuclear neutrophils (PMNs) are essential in initiation and execution of the acute inflammatory response and subsequent resolution of fungal infection. PMNs, however, may act as double-edged swords, as the excessive release of oxidants and proteases may be responsible for injury to organs and fungal sepsis. To identify regulatory mechanisms that may balance PMN-dependent protection and immunopathology in fungal infections, the involvement of different TLR-activation pathways was evaluated on human PMNs exposed to the fungus Aspergillus fumigatus. Recognition of Aspergillus and activation of PMNs occurred through the involvement of distinct members of the TLR family, each likely activating specialized antifungal effector functions. By affecting the balance between fungicidal oxidative and nonoxidative mechanisms, pro- and anti-inflammatory cytokine production, and apoptosis vs necrosis, the different TLRs ultimately impacted on the quality of microbicidal activity and inflammatory pathology. Signaling through TLR2 promoted the fungicidal activity of PMNs through oxidative pathways involving extracellular release of gelatinases and proinflammatory cytokines while TLR4 favored the oxidative pathways through the participation of azurophil, myeloperoxidase-positive, granules and IL-10. This translated in vivo in the occurrence of different patterns of fungal clearance and inflammatory pathology. Both pathways were variably affected by signaling through TLR3, TLR5, TLR6, TLR7, TLR8, and TLR9. The ability of selected individual TLRs to restore antifungal functions in defective PMNs suggests that the coordinated outputs of activation of multiple TLRs may contribute to PMN function in aspergillosis.

Generation of Th1 T cell responses directed to a HLA Class II restricted epitope from the Aspergillus f16 allergen

The Aspergillus allergen Asp f16 has been shown to confer protective Th1 T cell-mediated immunity against infection with Aspergillus conidia in murine models. Here, we use overlapping (11-aa overlap with preceding peptide) pentadecapeptides spanning the entire 427-aa coding region of Asp f16 presented on autologous dendritic cells (DC) to evaluate the ability of this antigen to induce Th1 responses in humans. Proliferative responses were induced in five out of five donors, and one line with a high frequency of interferon (IFN)-gamma-producing CD4(+) T cells in response to the complete peptide pool was characterized. This line was cytotoxic to autologous pool-pulsed and Aspergillus culture extract-pulsed targets. Limitation of cytotoxicity to the CD4(+) T cell subset was demonstrated by co-expression of the degranulation marker CD107a in response to peptide pool-pulsed targets. Cytotoxic T lymphocytes (CTL) killed Aspergillus hyphae and CTL culture supernatant killed Aspergillus conidia. By screening 21 smaller pools and individual peptides shared by positive pools we identified a single candidate sequence of TWSIDGAVVRT that elicited responses equal to the complete pool. The defined epitope was presented by human leucocyte antigen (HLA)-DRB1-0301. These data identify the first known Aspergillus-specific T cell epitope and support the use of Asp f16 in clinical immunotherapy protocols to prime protective immune responses to prevent or treat Aspergillus infection in immunocompromised patients.

99mTc-labeled interleukin-8 for scintigraphic detection of pulmonary infections

BACKGROUND

Interleukin (IL)-8 is a chemotactic cytokine that binds with high affinity to receptors on neutrophils. Previously we showed that (99m)Tc-labeled IL-8 is highly suitable for scintigraphic imaging in rabbit models of IM infection and of colitis.

STUDY DESIGN

(99m)Tc-labeled IL-8 was tested for its potential to image pulmonary infection in three experimental rabbit models: aspergillosis in immunocompromised rabbits, pneumococcal (Gram-positive) pneumonia, and Escherichia coli-induced (Gram-negative) pneumonia in immunocompetent rabbits (four rabbits in each group). A derivative of hydrazinonicotinamide was used as bifunctional coupling agent to label IL-8 with (99m)Tc. Biodistribution of (99m)Tc IL-8 was determined both by gamma-camera imaging and by counting dissected tissues at 6 h after injection.

RESULTS

(99m)Tc IL-8 enabled early (within 2 h after injection) and excellent visualization of localization and extent of pulmonary infection in each of the three experimental models of pulmonary infection. Uptake of (99m)Tc IL-8 in the infected lung and the contralateral lung was (in percentage of the injected dose per gram of tissue +/- SEM) at 6 h after injection 0.63 +/- 0.12 and 0.12 +/- 0.02 (aspergillosis), 0.89 +/- 0.04 and 0.44 +/- 0.04 (pneumococcal pneumonia), and 1.53 +/- 0.12 and 0.36 +/- 0.06 (E coli pneumonia), respectively. In the E coli model, uptake of (99m)Tc IL-8 in the focus of infection even exceeded uptake in the kidneys, the main clearing organs.

CONCLUSION

(99m)Tc IL-8 offers many advantages over the conventionally used radiopharmaceuticals to image pulmonary infection, (67)Ga citrate and radiolabeled leukocytes, ie, rapid and easy preparation, short time span between injection and imaging, low radiation burden and, most importantly, clear delineation of the infectious foci.

Differences in patterns of infection and inflammation for corticosteroid treatment and chemotherapy in experimental invasive pulmonary aspergillosis

Aspergillus fumigatus causes invasive pulmonary aspergillosis (IPA). This disease is one of the most life-threatening opportunistic infections in immunocompromised patients. The type of immunosuppressive regimen under which IPA occurs has rarely been investigated. In this study, we evaluated various parameters of the innate immune response during the progression of murine IPA induced by the intratracheal administration of A. fumigatus conidia as a function of two immunosuppressive treatments: a corticosteroid and a chemotherapeutic agent. We compared host responses various times after infection in terms of survival, pulmonary production of pro- and anti-inflammatory cytokines, cellular trafficking in the airways, lung injury, respiratory distress, and fungal development. We found that IPA pathogenesis involved predominantly fungal development in mice treated by chemotherapy and an adverse host response in mice treated with a corticosteroid. These previously unrecognized differences should be taken into account in evaluations of the pathogenesis of IPA in animal models.

Cytokines in host defense againstAspergillus: recent advances

Many aspects of antimicrobial host responses are orchestrated by a complex network of cytokines and their receptors. This review focuses on recent progress in our understanding of the function of cytokines in innate immune responses to Aspergillus. TNF, a recognition cytokine, has been shown to be required for initiation of the innate response in the mouse model of invasive aspergillosis. Several recruitment cytokines play critical roles in mediating influx of specific leukocytes to the site of infection in invasive aspergillosis. Among these, the ELR + subset of CXC chemokines and their receptor CXCR2 are critical to neutrophil recruitment, while CCL3/macrophage inflammatory protein (MIP)-1alpha and CCL2/ monocyte chemoattractant protein (MCP)-1 are critical to recruitment of monocyte-lineage leukocytes and NK cells, respectively. Of the activation cytokines, those associated with the Th-1 phenotype, including interleukin (IL)-12, IL-18, and interferon-gamma (IFN-gamma), are critical to protective responses to the infection. Conversely, the Th2-phenotype cytokines IL-4 and IL-10 contribute to progression of infection. Modulation of the immune response to Aspergillus by manipulating these mediators remains intriguing as a potential adjunctive treatment in patients with invasive aspergillosis.

Invasive aspergillosis in primary immunodeficiencies

Primary immunodeficiencies are rare and usually first manifest during childhood. Invasive aspergillosis is the leading cause of mortality in chronic granulomatous disease (CGD), reflecting the key role of the phagocyte NADPH oxidase in host defense against opportunistic fungi. Despite interferon-gamma prophylaxis, invasive filamentous fungal infections are a persistent problem in CGD. Key principles of management of fungal infections involve early recognition and aggressive treatment and appropriate surgical debridement of localized disease. Because CGD is a disorder of phagocyte stem cells in which the gene defects are well defined, it is a model disease to evaluate immune reconstitution through stem cell transplantation and gene therapy. Patients with the hyper-IgE syndrome with recurrent infections (Job syndrome) are prone to colonization of lung cavities (pneumatoceles) by Aspergillus species leading to local invasion and rarely disseminated infection. Other primary phagocytic disorders, T-cell disorders, and mitochondrial disorders are uncommonly associated with invasive aspergillosis. Taken together, these rare primary immunodeficiencies highlight the complex coordination of both innate and acquired pathways mediating host defense against Aspergillus infection.

Correlations between clinical and laboratory findings in patients investigated for aspergillosis

We investigated 120 patients suspected clinically to have pulmonary aspergillosis with different clinical manifestations "aspergilloma (Subgroup A), allergic bronchopulmonary aspergillosis (Subgroup B) and invasive pulmonary aspergillosis (Subgroup C)" and correlated between their clinical and laboratory findings and endogenous specific aflatoxin production. They were subjected to isolation of Aspergillus strains, measurement of serum total IgE and specific Aspergillus IgG by ELISA and identification of aflatoxin producing Aspergillus strains using fluorescence analysis of spectroline. Aspergillus was isolated from 45 patients (37.5%). Subgroup A had a negative statistically non-significant correlation between clinical and laboratory findings as regard total IgE and for Aspergillus IgG (only haemoptysis &weight loss had significant correlation with aspergillus IgG). Subgroup B & Subgroup C had positive, statistically significant correlation &negative statistically non significant correlation respectively as regard all clinical findings and both total IgE & serum IgG. This study also showed that 6 Aspergillus strains out of 45(13.3%) produced endogenous aflatoxin. It is concluded that a significant correlation that exists between clinical and serological findings in allergic pulmonary aspergillosis. Aflatoxins may be produced in vivo by strains of Aspergillus and may result in manifestations similar to those caused by ingestion of aflatoxin in food.

Aspergillosis in the CLEAR outcomes trial: working toward a real-world clinical perspective

Aspergillosis is a potentially lethal infection of immunocompromised patients. Until 10 years ago, antifungal therapy was largely limited to amphotericin B deoxycholate. Perceived poor response rates and inherent toxicities with amphotericin B deoxycholate were a major stimulus for the development of newer antifungals, including lipid-formulated amphotericin B, broad spectrum azoles, and echinocandins. Response rates to antifungals are highly dependent on the underlying diagnosis and degree of immune suppression of the patient. Patients at highest risk of death from aspergillosis also have very high mortality rates from other causes as well. Outcomes reported in historical literature reviews fail to distinguish between overall mortality and death attributable to aspergillosis. While this distinction can often be difficult to assess clinically, the net effect is to underestimate the therapeutic success rates of antifungals. The CLEAR (Collaborative Exchange of Antifungal Research) project started as a post approval survey to monitor clinical use of amphotericin B lipid complex (ABLC). The scope of the CLEAR project included collection of clinical data to assess outcomes in patients with invasive fungal infections treated with ABLC. Clinical data from more than 3500 patients were entered into the CLEAR database. Outcomes were assessed for 509 patients with documented aspergillosis and complete data records. Overall response rate was 63% (cured/improved/stable) with site-specific response rates of 61%, 59%, and 32% for lung, sinus, and central nervous system infections, respectively. Solid organ transplant recipients had higher response rates than patients with hematological malignancies. Bone marrow transplant recipients had the lowest response rates. Clinical response rates with ABLC reported in the CLEAR trial are higher than response rates reported for amphotericin B deoxycholate in other trials. Since it is unlikely we will see any new comparative Phase III trials for aspergillosis, CLEAR-type outcome studies will prove useful for the foreseeable future to guide clinical management of aspergillosis.

Reversal of long-term sepsis-induced immunosuppression by dendritic cells

Severe sepsis leads to long-term systemic and local immunosuppression, which is the cause of a number of complications, including pulmonary infection. A therapeutic strategy that reverses this immunosuppression is required, given the ongoing high mortality rate of patients who have survived a severe sepsis. The present study demonstrates that experimental severe sepsis renders the lung susceptible to a normally innocuous Aspergillus fumigatus fungus challenge, due to a dominant lung type 2 cytokine profile. Dendritic cells (DCs) obtained from the lungs of mice subjected to cecal ligation and puncture (CLP) model were skewed toward type 2 cytokine profile, which occurred with exaggerated expression of Toll-like receptor 2 (TLR2). The intrapulmonary transfer of bone marrow-derived DCs (BMDCs) in postseptic mice prevented fatal Aspergillus infection. This therapy reduced the overall inflammatory response and fungal growth in the lung, and promoted the balance of proinflammatory and suppressive cytokines in the lung. Thus, intrapulmonary DC supplementation appears to restore the pulmonary host response in the postseptic lung in our animal model. These data strongly suggest that lung DCs are profoundly affected as a consequence of the systemic impact of severe sepsis, and the identification of mechanisms that restore their function may serve as a key strategy to reverse sepsis-induced immunosuppression.

Predicting Outcome After Lung Resection for Invasive Pulmonary Aspergillosis in Patients With Neutropenia

STUDY OBJECTIVES

To investigate the factors that predict survival after lung resection for invasive pulmonary aspergillosis (IPA) in patients with neutropenia, in order to assist the selection of patients who are most likely to have a successful outcome.

DESIGN

Retrospective single-center study.

SETTING

University hospital hemato-oncologic isolation unit and division of thoracic surgery.

PATIENTS

Forty-one patients with hematologic disease and suspected IPA who underwent lung resection.

INTERVENTIONS

Lobectomy (n = 23), wedge resection (n = 16), and enucleation (n = 2).

RESULTS

Mortality within 30 days was 10% (4 of 41 patients). Major perioperative complications occurred in 10%. One death was possibly related to surgery (pleural aspergillosis). Of the patients with proven aspergillosis, 87.1% were cleared of infection, but fungal relapse occurred in 10%. Overall survival was 65% at 6 months, 58% at 12 months, and 40% at 5 years after surgery. Baseline characteristics and intraoperative data did not differ significantly between survivors and nonsurvivors at 6 months or 12 months after surgery. Perioperative complications did not significantly influence the outcome. Multivariate analysis of 12-month survival revealed that the variables, progression, or recurrence of the underlying hematologic disease (relative risk [RR], 4.64; 95% confidence interval [CI], 3.51 to 5.77; p < 0.0001), fungal relapse (RR, 5.06; 95% CI, 3.83 to 6.28; p < 0.0001), and to a minor extent the type of the underlying hematologic disease (p < 0.018) were the most important predictors of patient survival.

CONCLUSIONS

Lung resection for IPA is feasible with an acceptable operative risk. While at 10%, the perioperative mortality is considerable; the nonsurgical mortality is reported to be between 30% and 90%. Fungal infection is cleared in > 80% of patients. Mid- to long-term survival can be achieved if the underlying hematologic disease is under control. It is not yet possible to define a group of patients with IPA who are most likely to benefit from lung resection.

Candida- und Aspergillus-Antikorper-ELISA - Erwartungswerte positiver Antikorpernachweise aus Seren der klinisch-mykologischen Routinediagnostik. Candida- and Aspergillus-antibody-ELISA - expected positive antibody results in sera of the clinical-mycological routine diagnostics

Based on the ELISA results of more than 15000 serum samples of clinical mycological routine diagnostics, the expected frequency of positive antibody ELISA results within the immunoglobulin classes IgM, IgG and IgA was determined, to optimize the diagnostic assessment of first or single result of Candida or Aspergillus antibody ELISA. In general diagnostics the expected frequency of positive antibody ELISA results of the first sample within the immunoglobulin classes were as follows: Candida antibody IgM 6.1%; IgG 6.0%; IgA 2.1% and Aspergillus antibody IgM 11.4%; IgG 22.1% and IgA 5.1%, respectively. Using the Candida antibody ELISA as confirmation test only, percentages of positive antibody results in the first sample were 2.5 to 3 times higher than in general diagnostics. In follow-up examinations the Candida antibodies showed different kinetics within the immunoglobulin classes compared to those of the Aspergillus antibodies.

AFMP2 encodes a novel immunogenic protein of the antigenic mannoprotein superfamily in Aspergillus fumigatus

We cloned the Aspergillus fumigatus mannoprotein 2 (AFMP2) gene, which encodes a novel immunogenic protein (Afmp2p) of the antigenic mannoprotein superfamily, in A. fumigatus. Sequence analysis revealed that Afmp2p has 510 amino acid residues, with a predicted molecular mass of 51.5 kDa. Afmp2p has a putative N-terminal signal peptide, a putative C-terminal glycosylphosphatidylinositol membrane attachment signal sequence, and an upstream GAA cleavage site commonly used for cytoplasmic membrane attachment and implicated in fungal cell wall assembly. Upstream of the GAA cleavage site, Afmp2p contains a 302-amino-acid serine- and threonine-rich region as a site for potential O-glycosylation. Within this serine- and threonine-rich region, 13 repeats of ETSTPCE(T)(n) were observed. Western blot analysis of Afmp2p in A. fumigatus fungal cell lysate and culture supernatant and immunogold staining and electron microscopy showed that Afmp2p is predominantly secreted into the culture supernatant, whereas only minimal amounts can be detected in the cell lysate and cell wall. Finally, it was observed that patients with aspergilloma and invasive aspergillosis due to A. fumigatus develop a specific antibody response against recombinant Afmp2p. The abundance of Afmp2p in secreted form, its minimal cross-reactivity with Afmp1p, and the presence of an antibody response against Afmp2p in patients with A. fumigatus infections suggest that Afmp2p is a good candidate for complementing Afmp1p in serodiagnosis of A. fumigatus infections.

Infections Due to Aspergillus terreus: A Multicenter Retrospective Analysis of 83 Cases

Current in vitro and in vivo data indicate that invasive aspergillosis due to Aspergillus terreus is resistant to treatment with amphotericin B. Because little clinical data are available to guide therapy, we performed a retrospective cohort study of cases of invasive A. terreus infections from 1997-2002 to determine whether the use of voriconazole, compared with use of other antifungal therapies, led to an improved patient outcome. We analyzed a total of 83 cases of proven or probable invasive A. terreus infection (47% and 53%, respectively). A total of 66.3% of patients (55 of 83) died during management of IA, with 55.8% mortality (19 of 34 patients) in the voriconazole group and 73.4% mortality (36 of 49) in the group that received therapy with other antifungals. By use of Cox proportional hazards modeling, decreased mortality at 12 weeks was observed in those patients who received voriconazole (hazard ratio, 0.29; 95% CI, 0.15-0.56). Voriconazole is likely to be a better treatment choice for A. terreus infection than is a polyene.

Sudden death secondary to fulminant intracranial aspegillosis in a healthy teenager after posterior fossa surgery: the role of corticosteroids and prophylactic recommendations

Postoperative complications from corticosteroids in neurosurgical patients are not uncommon. Too often the deleterious immunosuppressive effects of corticosteroids are overlooked in neurosurgery patients and can lead to serious and lethal infections.

EXPERIMENTAL DESIGN

case report of a 16-year-old healthy male who presented for elective resection of a recurrent juvile pilocytic astrocytoma of the posterior fossa 4 years after initial resection.

SETTING

major University institutional practice.

INTERVENTION/RESULTS

a standard suboccipital craniotomy with gross total resection. Postoperatively, the patient suffered from posterior fossa syndrome and diminished gag reflex requiring nasogastric feeds with progressive improvement. While awaiting transfer to a rehabilitation center on postoperative day 12 he suffered a sudden temperature spike followed by neurological decline. A stat computed tomography scan of the brain revealed a diffuse miliary process with severe cerebral edema. Sputum and cerebrospinal fluid cultures identified Aspergillus. Despite immediate therapy to combat the malignant cerebral edema, the patient died within 24 hours of onset of the symptoms. Corticosteroids are used routinely in neurosurgery to combat cerebral edema without much consideration for the immunosuppressive effects. This case demonstrates how the immunosuppressive effects of corticosteroids can lead to a fulminant lethal fungal infection. Neurosurgeons should be aware of the anticatabolic medications now available to combat the deleterious side effects of corticosteroids.

Postoperative spondylodiscitis from Aspergillus fumigatus in immunocompetent subjects

The authors describe a case of spondylodiscitis from Aspergillus fumigatus which occurred subsequent to surgery for lumbar disc herniation in a non-immunodepressed patient. The results obtained by combined medical and surgical treatment are discussed.

Vaccinate against aspergillosis! A call to arms of the immune system

Invasive aspergillosis is a devastating and increasingly common disease, seen almost exclusively in immunosuppressed patients. Immunizing an immunocompromised host would seem to be a formidable task; however, virulence factors and immunogens of the pathogen have now been identified and could be targeted, mapping of the genome sequence of the pathogen will soon be completed, and the protective host immune responses and cytokine networking are better understood. These facts, together with recent advances in vaccine science, make consideration of such an approach now possible. Some populations that are at risk for aspergillosis might be likely candidates for receiving the first vaccinations against aspergillosis, or vaccination of a stem cell donor might be considered in some circumstances. Successful immunizations have been demonstrated in turkeys and mice.

Invasive aspergillosis in patients with hematologic malignancies

Invasive aspergillosis is an increasingly common and often fatal opportunistic fungal infection in patients with hematologic malignancies. Prolonged and profound neutropenia remains a key risk factor for the development of invasive aspergillosis. However, qualitative deficiencies in host immune responses resulting from prolonged corticosteroid therapy, graft-versus-host disease, and cytomegalovirus infection are important risk factors for the recurrence and progression of Aspergillus infections after bone marrow recovery. Early diagnosis of invasive aspergillosis remains a challenge, and few tools are available for monitoring its course once the diagnosis is established. Even with the recent introduction of new antifungal therapies, mortality in patients with invasive aspergillosis remains high, and uniformly effective prophylaxis or preemptive therapeutic strategies are lacking. Strategies such as combination antifungal therapy and immunotherapy often are used as first-line treatment approaches in patients with documented invasive aspergillosis despite a paucity of clinical trial data. Recent advances in our understanding of the epidemiology, pathogenesis, and treatment of invasive aspergillosis in patients with hematologic malignancies are reviewed. The problems and controversies associated with defining optimal treatment strategies for invasive aspergillosis in this heavily immunocompromised population are highlighted.

[Invasive aspergillosis in immunocompromised patients]

AIM

To analyse results of treatment of invasive aspergillesis in immunocompromised patients for 2000-2002.

MATERIAL AND METHODS

The study was made of patients who, when treated with antibiotics, exhibited foci in the lungs typical for invasive aspergillesis. Aspergillas were detected in the sputum, bronchoalveolar lavage, bronchial wash-ups, aspergilla antigen (galactomannan) was detected in the blood.

RESULTS

Invasive aspergillesis was diagnosed in 25 patients. 13 (52%) patients were treated with adjuvant glucocorticoids. 19 (76%) patients had neutropenia. All the patients had fever. Foci in the lungs were in 24 patients. Aspergillas were detected in 15 patients, a positive antigen galactomannan in 7 patients. A. Fumigatus, A flavus, A. Niger occurred in 67, 26.5 and 6.5% patients, respectively. All the patients received amphotericin B (median of the treatment reached 38 days, total dose 880-3500 mg). In 5 patients amphotericin B was replaced for liposomal amphotericin B because of high creatinine. 7 patients continued with itraconasol in a dose 400-600 mg/day. The foci were removed in 3 patients. The cure was achieved in 12 patients, 13 patients, 13 patients died (cause of death--respiratory insufficiency).

CONCLUSION

Lethality in invasive aspergillesis in immunocompromised patients remains high--52%. Cultural detection of mycelial fungi was, as a rule, delayed. Early diagnosis of the disease requires monitoring of the aspergilla antigen in the blood and computer tomography of the chest especially in fever persisting in the treatment of wide-spectrum antibiotics.

Thymosin alpha 1 activates dendritic cells for antifungal Th1 resistance through toll-like receptor signaling

Dendritic cells (DCs) show a remarkable functional plasticity in the recognition of Aspergillus fumigatus and orchestrate the antifungal immune resistance in the lungs. Here, we show that thymosin alpha 1, a naturally occurring thymic peptide, induces functional maturation and interleukin-12 production by fungus-pulsed DCs through the p38 mitogen-activated protein kinase/nuclear factor (NF)-kappaB-dependent pathway. This occurs by signaling through the myeloid differentiation factor 88-dependent pathway, involving distinct Toll-like receptors. In vivo, the synthetic peptide activates T-helper (Th) cell 1-dependent antifungal immunity, accelerates myeloid cell recovery, and protects highly susceptible mice that received hematopoietic transplants from aspergillosis. By revealing the unexpected activity of an old molecule, our finding provides the rationale for its therapeutic utility and qualify the synthetic peptide as a candidate adjuvant promoting the coordinated activation of the innate and adaptive Th immunity to the fungus.

The Contribution of the Toll-Like/IL-1 Receptor Superfamily to Innate and Adaptive Immunity to Fungal Pathogens In Vivo

In vitro studies have indicated the importance of Toll-like receptor (TLR) signaling in response to the fungal pathogens Candida albicans and Aspergillus fumigatus. However, the functional consequences of the complex interplay between fungal morphogenesis and TLR signaling in vivo remain largely undefined. In this study we evaluate the impact of the IL-1R/TLR/myeloid differentiation primary response gene 88 (MyD88)-dependent signaling pathway on the innate and adaptive Th immunities to C. albicans and A. fumigatus in vivo. It was found that 1) the MyD88-dependent pathway is required for resistance to both fungi; 2) the involvement of the MyD88 adapter may occur through signaling by distinct members of the IL-1R/TLR superfamily, including IL-1R, TLR2, TLR4, and TLR9, with the proportional role of the individual receptors varying depending on fungal species, fungal morphotypes, and route of infection; 3) individual TLRs and IL-1R activate specialized antifungal effector functions on neutrophils, which correlates with susceptibility to infection; and 4) MyD88-dependent signaling on dendritic cells is crucial for priming antifungal Th1 responses. Thus, the finding that the innate and adaptive immunities to C. albicans and A. fumigatus require the coordinated action of distinct members of the IL-1R/TLR superfamily acting through MyD88 makes TLR manipulation amenable to the induction of host resistance to fungi.

Treatment of murine systemic aspergillosis with polyene-intralipid admixtures

The objective of this research was the evaluation of the activity of admixtures of amphotericin B (AMB)--intralipid (AMB-IL) and nystatin (Ny)--intralipid (Ny-IL) against experimental systemic aspergillosis in immunocompromised mice. ICR mice were transiently immunosuppressed by intraperitoneal (i.p.) administration of cyclophosphamide (CY). Three days post CY administration the mice were inoculated intravenously (i.v.) with Aspergillus fumigatus conidia. The animals were treated with various doses of AMB-IL or Ny-IL admixtures administered i.v. for 5 consecutive days, starting 2 h after infection. The mean survival rate (MSR) and mean survival time (MST) were evaluated during an observation period of 30 days in comparison to untreated infected mice and to animals treated with conventional formulations of these drugs. These experiments showed that AMB-IL increased significantly the MSR. Specifically, the MSR ranged in dependence of dose, between 48 and 65.7% vs. 0% of the untreated (P < 0.001, anova analysis) and 39.7% of AMB-treated animals (P < 0.01). The MSR of the Ny-IL-treated mice ranged between 16.2 and 40% in comparison to 0% of the untreated group (P < 0.001). Treatment with both admixtures prolonged the MST of the mice (AMB-IL: 17.3-23.07 days; Ny-IL: 8.61-16.8 days) in comparison to either untreated (6.13 days) or AMB treated animals (15.23 days). The data obtained in this study show that both AMB-IL and Ny-IL formulations, particularly AMB-IL at the highest dose, were effective in the treatment of experimental systemic aspergillosis.

Bifidobacterium lipoteichoic acid and false ELISA reactivity in aspergillus antigen detection

A major difficulty with the detection of circulating galactomannan, a cell-wall polysaccharide released by Aspergillus sp during growth, in the serodiagnosis of invasive aspergillosis is the occurrence of false-positive ELISA results, especially in neonates and infants. On the basis of molecule similarity, we postulate that a lipoteichoic acid of Bifidobacterium sp can act as epitope for the monoclonal antibody used in the ELISA. The neonatal gut is heavily colonised with Bifidobacterium sp and these bacteria or their lipoteichoic acid might cause ELISA reactivity with serum after translocation because of immaturity of the intestinal mucosa. If our hypothesis is correct, we might find a method to discriminate between false-positive and true-positive ELISA results and thereby prevent unnecessary pre-emptive treatment of patients.

Hypersensitivity pneumonitis due to occupational inhalation of fungi-contaminated corn dust

Hypersensitivity pneumonitis or extrinsic allergic alveolitis can be defined as a lung disease caused by a wide group of antigens that reach the lung by inhalation of organic and/or inorganic dust of various sources. The dust of the stored maize corn has been reported as cause of respiratory symptoms. During the storage process, maize corn dust can be contaminated by moulds and thermophilic actinomycetes, which have not been described until now as the causing antigens of these symptoms. We present a case of occupational hypersensitivity pneumonitis in an agricultural worker who cultured and stored maize corn. Clinical findings, precipitating antibodies, and evolution after having removed him from his work, confirmed the diagnosis. In our case, Aspergillus species contaminating the maize corn dust are probably the antigens that caused the disease.

Biatrial aspergillosis in a patient with immunocompetency

A 24-year-old man presented with a 24-hour history of pain and numbness in his left arm. The patient's clinical presentation of peripheral embolism was corroborated by angiography. Echocardiographic study showed masses in both right and left atria. Pathologic specimen from the embolus confirmed the diagnosis of aspergillosis.

Intrapulmonary targeting of RANTES/CCL5-responsive cells prevents chronic fungal asthma

Regulated upon activation in normal T cells, expressed, and secreted (RANTES)/CCL5 is abundantly expressed during atopic asthma, suggesting that it is an important mediator of this disease. The contribution of intrapulmonary RANTES/CCL5-sensitive cells during Aspergillus fumigatus-induced airway disease in mice was assessed in this study. The intranasal delivery of a chimeric protein comprised of RANTES/CCL5 and a truncated version of Pseudomonas exotoxin A (RANTES-PE38) significantly attenuated serum IgE, peribronchial eosinophilia, and airway hyperreactivity when it was administered from day 0 to 15 after intratracheal conidia challenge in A. fumigatus-sensitized mice but had little effect when delivered from day 15 to 30 after conidia challenge. Intranasal RANTES-PE38 treatment enhanced macrophage recruitment and accelerated fungal clearance in the lungs of RANTES-PE38-treated mice. These data reveal a major role for RANTES/CCL5 and its receptors in the development of fungal asthma yet reveal only a modest role in the chronic remodeling of the allergic airway in this disease.

Case report: Invasive aspergillosis successfully treated with voriconazole without recurrence during subsequent bone marrow transplantation

Invasive aspergillosis is an important cause of morbidity and mortality among immunosuppressed oncology patients. We report a 17-year-old patient with a T cell acute lymphocytic leukemia and invasive aspergillosis treated with voriconazole who remained infection-free during bone marrow transplant.

Aspergillose pulmonaire invasive chez les enfants immunodeṕrimés méthodes diagnostiques et classification

Invasive aspergillosis is an opportunistic infection, with frequent lung involvement. High-risk children are allogenic bone marrow recipients, and those with hematological malignancies, aplastic anemia or chronic granulomatous disease. Profound and prolonged neutropenia, and corticosteroid therapy are the most important predisposing factors. Building and demolition works represent the major environmental risk factor. The diagnosis of invasive aspergillosis remains difficult to establish. Clinical manifestations are non-specific. Early thoracic computed tomographic scan shows halo sign in most cases. Subsequently appears the air crescent sign. Galactomannan research by sandwich ELISA can be useful in serum and in bronchoalveolar lavage fluid. Aspergillus DNA detection by PCR is still not standardized. Culture of the organism allows species identification. Aspergillus hyphae can be found at cytological examination, but a biopsy specimen is usually required to affirm tissue damage. A new classification of invasive fungal infections in immunocompromised patients was recently proposed by experts from the European Organization for Research and Treatment of Cancer and from the Mycoses Study Group of the National Institute of Allergy and Infectious Diseases. On the basis of host linked criteria, microbiological, clinical and radiological features, invasive aspergillosis is classified as proven, probable or possible. These definitions should not be used to guide clinical practice in therapy, but they will improve the quality of epidemiological data, and help the comparison of clinical trial results.

Polyene and cytokine treatment of experimental aspergillosis

The aim of the present study was to assess the efficacy of amphotericin B (AMB), AMB-intralipid admixture (AMB-IL) or nystatin-IL formulation (Ny-IL) in combination with granulocyte colony stimulating factor (G-CSF) in treatment of experimental murine aspergillosis. ICR mice were immunosuppressed by cyclophosphamide and 3 days later inoculated intravenously (i.v.) with Aspergillus fumigatus. Treatment was initiated 2 h later and administered for 5 consecutive days (polyenes, i.v.; G-CSF, intraperitoneally). Combination therapy, particularly G-CSF with AMB or AMB-IL, significantly increased the survival rate (up to 87.3%) and prolonged the mean survival time (MST) (up to 28.8 days) in comparison to untreated controls (0% survival, MST 6.7 days) and to treatment with polyenes alone (up to 51.5% survival, MST 18.4 days). These data indicate that combination therapy could be beneficial for management of disseminated aspergillosis in humans.

Pulmonary Aspergillosis in a Patient with Chronic Granulomatous Disease: Confirmation by Polymerase Chain Reaction and Serological Tests, and Successful Treatment with Voriconazole

A 25-year-old male with chronic granulomatous disease developed severe bilateral pulmonary aspergillosis confirmed by a positive result of polymerase chain reaction for Aspergillus species from sputum and positive serological tests for Aspergillus. He was successfully treated with voriconazole. The diagnostic difficulties and the new therapeutic options in the era of new antifungal agents are discussed.

[Severe Legionnaire's disease revealing an invasive aspergillosis in an apparently immunocompetent patient]

INTRODUCTION

Invasive aspergillosis, a sever disease, usually occurs in immuno-depressed patients. However, it may also develop in presumably immuno-competent patients.

OBSERVATION

A 54-year-old man, smoker, was hospitalised for hypoxemia of the right lung and septic shock, rapidly requiring mechanical ventilation combined with administration of vasopressors, and followed by dialysis because of the rapid worsening of an acute kidney failure. The diagnosis of pulmonary Legionnaire's disease was made on the second day in view of the positivity of the urinary legionella antigen. The progression of the disease was marked by the discovery of a histologically documented gastric aspergillosis and three abscessed intracerebral lesions within the context of a strongly positive aspergillus antigenemia. The disease worsened and the patient died on D 17, despite the antibiotic and anti-aspergillus treatments, haemodynamic support and dialysis.

DISCUSSION

To our knowledge, the association of invasive aspergillosis and severe Legionnaire's disease has never been described in an presumably immunocompetent patient. This clinical case suggests the existence, other than the usual risk factors of invasive aspergillosis that characterise profound states of immunodepression, of more subtle alterations in the immune system that may enhance this type of infection.

Chronic cavitary and fibrosing pulmonary and pleural aspergillosis: case series, proposed nomenclature change, and review

We describe 18 nonimmunocompromised patients with chronic pulmonary aspergillosis. Duration of the disease ranged from several months to >12 years. All 18 patients had prior pulmonary disease. Weight loss, chronic cough (often with hemoptysis and shortness of breath), fatigue, and chest pain were the most common symptoms. All 18 patients had cavities, usually multiple and in 1 or both upper lobes of the lung, that expanded over time, with or without intraluminal fungal balls. All had detectable Aspergillus precipitins and inflammatory markers. Elevated levels of total immunoglobulin E were seen in 78% of patients and of Aspergillus-specific immunoglobulin E in 64%. Directed lung biopsies showed chronic inflammation, necrosis, or granulomas without hyphal invasion. Antifungal therapy with itraconazole resulted in 71% of patients improved or stabilized, with relapse common. Interferon-gamma treatment was useful in 3 patients. In azole nonresponders, modest responses to intravenous amphotericin B (80%) followed by itraconazole were seen. Surgery removed disease but postoperative pleural aspergillosis was inevitable. Indicators of good long-term medical outcomes were mild symptoms, thin-walled quiescent cavities, residual pleural fibrosis, and normal inflammatory markers.

Caspofungin salvage therapy in a neutropenic patient with probable invasive aspergillosis: a case report

A 47-year-old man with acute lymphocytic leukemia was admitted in intensive care unit (ICU) because of respiratory failure. He had febrile neutropenia and probable invasive pulmonary aspergillosis (IA). Amphotericin B renal toxicity and clinical deterioration prompted a shift to caspofungin and resulted in a successful response.

Chronic lung infection in children

Tuberculosis and aspergillosis are two of the most common chronic lung infections that occur in children. They both present in a variety of ways, acutely or insidiously. Tuberculosis is increasing in incidence due to increased immigration and the HIV pandemic. Symptoms can range from subclinical to acute sepsis with respiratory distress requiring intensive care support. Aspergillus is an important pathogen, particularly in patients who are immunocompromised either due to organ impairment such as cystic fibrosis or due to primary or secondary suppression of the immune system. Aspergillosis can also present with mild to fulminant symptomatology. Imaging is often the cornerstone of diagnosis. This article concentrates on the wide range of radiological features that these two organisms can cause.

Binding of live conidia of Aspergillus fumigatus activates in vitro-generated human Langerhans cells via a lectin of galactomannan specificity

Aspergillus fumigatus is the most common aetiological fungus responsible for human pulmonary aspergilloses. This study investigated the primary contact between Langerhans cells (LC), corresponding to dendritic cells present in pulmonary mucosa and live conidia of A. fumigatus. LC play a key role in antigen presentation for initiation of the primary T cell response. In vitro-generated LC (iLC) were differentiated from cultured human cord blood CD34+ cells and incubated at 4 degrees C or 37 degrees C with fluorescein-isothiocyanate (FITC)-stained conidia or control latex beads. In vitro, conidia were shown by microscopy and cytometry to adhere to iLC in a dose- and time-dependent manner. This adhesion was not limited to iLC because interstitial dendritic and other cells also fluoresced in the presence of conidia-FITC. A lectin other than mannose receptor-type lectin was demonstrated to be responsible of conidial binding. Inhibition of binding was observed with heterologous galactomannan and EDTA, indicating a C-lectin-like receptor with galactomannan structure specificity. After binding only a few conidia were internalized in acidic vesicles, as indicated by the cessation of conidial fluorescence. Conidial binding was followed by activation and maturation of iLC, suggesting that LC present in the lung may play a role in cellular host defence against aspergilloses.

Differential role of MyD88 in macrophage-mediated responses to opportunistic fungal pathogens

Toll-like receptors mediate macrophage recognition of microbial ligands, inducing expression of microbicidal molecules and cytokines via the adapter protein MyD88. We investigated the role of MyD88 in regulating murine macrophage responses to a pathogenic yeast (Candida albicans) and mold (Aspergillus fumigatus). Macrophages derived from bone marrow of MyD88-deficient mice (MyD88(-/-)) demonstrated impaired phagocytosis and intracellular killing of C. albicans compared to wild-type (MyD88(+/+)) macrophages. In contrast, ingestion and killing of A. fumigatus conidia was MyD88 independent. Cytokine production by MyD88(-/-) macrophages in response to C. albicans yeasts and hyphae was substantially decreased, but responses to A. fumigatus hyphae were preserved. These results provide evidence that MyD88 signaling is involved in phagocytosis and killing of live C. albicans, but not A. fumigatus. The differential role of MyD88 may represent one mechanism by which macrophages regulate innate responses specific to different pathogenic fungi.

Humoral Immune Response in Aspergillosis: An Immunodominant Glycoprotein of 35 kDa from Aspergillus flavus

A glycoprotein preparation containing 70% carbohydrates and 30% proteins was isolated from the mycelium of two strains of Aspergillus flavus and fractionated by ConA-Sepharose affinity chromatography. An immunodominant 35-kDa antigen was detected in a ConA-bound fraction (B fraction). It contained mannose and galactose in a 1.4:1.0 ratio. This antigen seems to be able to elicit an antibody response in patients with aspergillosis and in rabbits immunized with A. flavus whole cells. The carbohydrate units of the BF fraction appeared to be responsible for the antigenicity, since treatment with periodate removed most of the antibody binding capacity.

Allergic Aspergillus flavus rhinosinusitis: a case report from Qatar

Fungal involvement in rhinosinusitis is classified into four major forms: allergic, mycetoma, chronic invasive (indolent) and acute invasive (fulminant). It can become life threatening if not diagnosed and treated properly. The preliminary diagnosis is usually made by nasal endoscopy and computed tomography (CT) imaging, but tissue biopsy and culture are of vital importance in confirming the disease and in planning treatment. We present a case of allergic fungal rhinosinusitis (AFS) caused by Aspergillus flavus. The clinical manifestation of the disease was the presence of an extensive left nasal polyp. An allergic workup revealed systemic eosinophilia (11.7%), high serum IgE levels (1,201 IU/ml) and a positive skin test for Aspergillus. CT scan showed a total opacification and expansion of the left nasal cavity and sinuses, with a secondary inflammatory reaction on the right side. There was no bony erosion beyond the sinus walls. The patient was operated on using an endoscopic approach (polypectomy and ethmoidectomy), where an abundant amount of allergic fungal mucin and dark crusts were found filling the sinuses. Fungal hyphae were evident in histopathological sections of the removed mucin. Culture of the debris resulted in the growth of Aspergillus flavus. The patient received a full course of systemic and topical steroids. The serum IgE level had dropped to 353 IU/ml and the peripheral eosinophil count to normal (1.38%) by the 10th postoperative month. Surgical debridement and corticosteroids may keep the disease quiescent for a long time.

The radiological spectrum of invasive aspergillosis in children: a 10-year review

BACKGROUND

Invasive aspergillosis is an uncommon but life-threatening event in the immunocompromised child. Attempts at fungal isolation are often unrewarding and a high index of radiological suspicion is essential in the early diagnosis of infected children.

OBJECTIVE

To document the radiological spectrum of disease in invasive aspergillosis in the paediatric population.

MATERIALS AND METHODS

A retrospective review of the imaging performed in 27 consecutive patients (age 7 months to 18 years) with documented invasive Aspergillosis encountered over a 10-year period at a single institution.

RESULTS

Radiographic findings of pulmonary disease (20 patients) included segmental and multilobar consolidation, perihilar infiltrates, multiple small nodules, peripheral nodular masses and pleural effusions. No cavitating lesions were seen on CXR. Small cavitating nodules were present on CT in two of eight children. Chest wall disease was particularly associated with underlying chronic granulomatous disease. Disseminated disease manifested as osteomyelitis (n=5), cerebral (n=3), oesophageal (n=1), hepatic (n=2), renal (n=2) and cutaneous (n=5) involvement. Imaging findings are discussed. Twelve patients (44%) subsequently died from Aspergillus-related complications.

CONCLUSIONS

Invasive aspergillosis presents with a wide variety of radiographic findings involving multiple organ systems. Respiratory findings are varied but often non-specific, and a high index of suspicion is necessary in immunocompromised patients. In contrast to adult disease, the incidence of cavitation of pulmonary lesions appears low.

Allergic fungal sinusitis. A naso-sinusal specific hyperreactivity for an infectious disease?

Allergic fungal sinusitis (AFS) is a rare disease of naso-sinusal complex affecting mainly young, immunocompetent adults who complain of chronic rhinitis and/or recurrent nasal polyposis despite medical and/or surgical treatment. Aim of the study is to analyse, from an allergological and otorhinolaryngological point of view, patients affected by the so-called "allergic fungal sinusitis" in order to better define the relationship between fungi present in naso-sinusal secretions and the host's immunoreactivity. From February 2001 to January 2002, 24 selected patients (13 male 11 female) age range 25-65 years (mean 45), with chronic rhinosinusitis, with a positive fungal examination of nasal secretion, underwent allergological evaluation. All patients were positive for diagnostic criteria of allergic fungal sinusitis and, in all patients, nasal lavage was performed for microscopic examination by fluorescence. Samples were then cultured on Sabouraud growth media for identification of the fungus. Skin prick tests (SPT) were then performed with the 15 main inhalant allergens and twelve fungal allergens (Bracco). The total IgE serum level (PRIST), the specific fungal IgE and the eosinophilic cationic protein were then investigated by means of an immuno-fluorine enzymatic method. Finally, a nasal provocation test was carried out with diluted solutions (1/100, 1/10) and with a pure solution of fungal allergens, selected according to microbiological examination of nasal secretion of each subject. Prick tests were positive for seasonal and perennial allergens in 5 patients (21%), while prick tests with fungi were positive in only 4 patients (16.6%). Total IgE levels were higher than in normals (200 KU/l) in 6 patients (25%) (mean 364.74 KU/l). In another 18 patients, total IgE were normal. Specific IgE levels for the tested fungi and eosinophilic cationic protein levels were within normal range in all patients. Nasal provocation test was negative in all patients. Presence of fungi in nasal secretions of patients with AFS does not appear to be correlated with an allergic status to the isolated fungus. A role for IgE in either the aetiology or the pathophysiology of allergic fungal sinusitis in unlikely, and probably the diagnostic criteria for allergic fungal sinusitis should not include type I hypersensitivity, since no confirmed evidence exists that IgE-mediated type I hypersensitivity is involved in the pathophysiology of allergic fungal sinusitis.