[Fatal sino-orbital aspergillosis in an immunocompetent case]

The paranasal sinus infections caused by Aspergillus spp. are usually presented clinically with mild symptoms, however they may lead to invasive disease and mortality especially in immunocompromised individuals. In this report a fatal case of sino-orbital aspergillosis developed in an immunocompetent patient has been presented. Seventy-four years old female patient was admitted to the hospital with the complaints of fever and progressively increasing headache that continued for 15 days. Due to the development of nausea, vomiting, loss of consciousness and stiff neck in the following days, cerebrospinal fluid (CSF) sample was obtained. Direct microscopic examination of the Gram and acidfast staining of the CSF sample revealed no microorganisms, no growth was detected in CSF culture and PCR amplification was negative for Herpes simplex virus and Mycobacterium tuberculosis. Since no response was achieved by empirical ceftriaxone, ampicillin and conventional anti-tuberculosis treatment and tachypnea, proptosis and progressive respiratory failure developed in the patient, she was transferred to the intensive care unit. The radiological examination revealed soft tissue lesion filling the sphenoid sinus, extending to the nasal cavity and suprasellar cistern, destruction of bones, dilated orbital vein, cavernous sinus thrombosis and infarction on left cerebral peduncule. Patient was operated and pus and fungus ball were aspirated from the openings of both sphenoid sinuses. Gomori methenamine silver, periodic acid-Schiff and haematoxylin-eosine staining of the operational material exhibited dichotomously branching hyphae. The patient was diagnosed as invasive sino-orbital aspergillosis based on the clinical, radiological and histopathological findings. Despite antifungal therapy and surgical debridement, the patient died. It should always be kept in mind that aspergillosis can develop in immuncompetent individuals. Delay in diagnosis and treatment may lead to fatality. Thus multidiciplinary approach is necessary for early diagnosis and successful treatment of aspergillus infections.

Acute phase protein concentrations in dogs with nasal disease

The concentrations of C-reactive protein (CRP), serum amyloid A, haptoglobin (Hp) and α(1)-acid glycoprotein were measured in dogs with clinical signs of nasal disease and compared with those of healthy dogs in order to determine the expression of these proteins in cases of canine nasal disease. A significant difference (P<0.001) between the symptomatic group and the control group was found for both CRP and Hp. Among the animals with nasal disease, a significant intergroup difference (P<0.05) was found in the expression of Hp between dogs with aspergillosis and those with chronic rhinitis.

[A systematic review of the accuracy of diagnostic test of serum galactomannan antigen detection for invasive aspergillosis]

OBJECTIVE

To assess the value of galactomannan (GM) double-direct sandwich enzyme-linked immunosorbent assay (ELISA) in the diagnosis of invasive aspergillosis (IA).

METHODS

A search in MEDLINE, EMbase, OVID, CBMdisc and CHKD from Jan. 1991 to Dec. 2008 was conducted to collect all articles about diagnostic tests of serum GM detection. Then the methodological quality was assessed by QUADAS-items, sources of heterogeneity investigated, pooled effect quantities evaluated, and meta-analysis studies, SROC curves, and subgroup analysis performed.

RESULTS

Thirty-six articles with a population of 4959 patients were included. The average prevalence of IA was 10%(532/4959). Our meta-analysis reported a median heterogeneity (I(2) = 48.6%, P < 0.05), with a pooled DOR value of 19.10 (95%CI 12.67 - 28.79), a pooled sensitivity of 0.66 (95%CI 0.61 - 0.70), a pooled specificity of 0.90 (95%CI 0.89 - 0.90), a pooled positive likelihood ratio of 5.48 (95%CI 4.27 - 7.02), a pooled negative likelihood ratio of 0.38 (95%CI 0.29 - 0.50), and an area under curve of SROC 0.88. The rate of underdiagnosis of serum GM detection was 34% (168/490) and the rate of misdiagnosis was 10% (466/4469). With a rise in the cut-off value the sensitivity of GM test decreased and specificity increased. Two consecutive positive tests decreased the sensitivity but increased the specificity. Age had no significant effect on the diagnosis by GM test. Both antifungal prophylaxis and antifungal therapy had no significant effect on sensitivity and specificity of GM test for IA diagnosis.

CONCLUSION

Serum GM detection is an effective diagnostic tool for invasive aspergillosis in high-risk populations.

Central nervous system aspergillosis in an immunocompetent patient

A 12-year-old girl was admitted to the Emergency Department with seizures and headache for 2 months. A CT scan and MRI showed a mass in the right frontal lobe with obvious mass effect. Surgery was carried out, and the resultant pathology was found to be aspergillosis. This study reports aspergillosis in an immunocompetent host following recurrent fungal otitis media. Although this condition is rare, it should be considered in patients with a history of fungal infections.

Anti-Aspergillus human host defence relies on type 1 T helper (Th1), rather than type 17 T helper (Th17), cellular immunity

Both interferon-gamma-producing type 1 T helper (Th1)- and interleukin-17 (IL-17)-producing Th17 cells have been proposed to be involved in anti-fungal host defence. Although invasive aspergillosis is one of the most severe human fungal infections, little is known regarding the relative importance of the Th1 versus Th17 cellular immune pathways for the human anti-Aspergillus host defence. Using human peripheral blood mononuclear cells and a system consisting of monocyte-derived macrophages with lymphocytes, we found that Aspergillus fumigatus is a weak inducer of human IL-17 but induces a strong Th1 response. These data were validated by the very low IL-17 levels in bronchoalveolar lavage fluid and serum of patients with invasive aspergillosis. Surprisingly, live A. fumigatus reduced IL-17 production induced by mitogenic stimuli. This effect was mediated through the propensity of A. fumigatus to metabolize tryptophan and release kynurenine, which modulates the inflammatory response through inhibition of IL-17 production. In conclusion, A. fumigatus does not stimulate production of IL-17 and human host defence against aspergillosis may not rely on potent Th17 responses.

Resistance of MBL gene-knockout mice to experimental systemic aspergillosis

Mannose binding lectin (MBL) is a protein of the collectin family that appears important in resistance to invasive pulmonary aspergillosis. We assessed the role of MBL in experimental systemic aspergillosis. MBL-sufficient C57BL/6 (WT) mice and B6.129S4--Mb11(tm1Kata) Mb12(tm1Kata)/J MBL A and C gene-knockout (KO) mice were infected intravenously with different inocula of Aspergillus fumigatus conidia. WT and KO mice were dose-responsively susceptible. In no instance were the KO mice more susceptible than WT. At the highest inoculum, all WT and 90% of KO mice died on day 4 (P>0.05). Reduction of the inoculum to 5.5 x 10(6) conidia was lethal, but comparison showed KO mice less susceptible to lethal infection (P<0.015). At the lowest inoculum used, deaths of KO mice were delayed, but survival was not significantly different than WT (P>0.05). These results suggest MBL may play a deleterious role in systemic aspergillosis.

Aspergillus fumigatus conidial melanin modulates host cytokine response

Melanin biopigments have been linked to fungal virulence. Aspergillus fumigatus conidia are melanised and are weakly immunogenic. We show that melanin pigments on the surface of resting Aspergillus fumigatus conidia may serve to mask pathogen-associated molecular patterns (PAMPs)-induced cytokine response. The albino conidia induced significantly more proinflammatory cytokines in human peripheral blood mononuclear cells (PBMC), as compared to melanised wild-type conidia. Blocking dectin-1 receptor, Toll-like receptor 4 or mannose receptor decreased cytokine production induced by the albino but not by the wild type conidia. Moreover, albino conidia stimulated less potently, cytokine production in PBMC isolated from an individual with defective dectin-1, compared to the stimulation of cells isolated from healthy donors. These results suggest that β-glucans, but also other stimulatory PAMPs like mannan derivatives, are exposed on conidial surface in the absence of melanin. Melanin may play a modulatory role by impeding the capability of host immune cells to respond to specific ligands on A. fumigatus.

Different expression of dectin-1 and Toll-like receptor 2 in the lungs of different immune status mice infected with Aspergillus fumigatus

BACKGROUND

Invasive pulmonary aspergillosis (IPA) is a severe and frequently fatal disease in patients receiving treatment with immunosuppressive agents such as cyclophosphamide. Aspergillus fumigatus (A. fumigatus) now is a leading cause of IPA. Dectin-1 and Toll-like receptor 2 (TLR2) are important pattern recognition receptors involved in immune responses to A. fumigatus in vitro. However, the expression of the two receptors during the infection of A. fumigatus in vivo is not completely understood. The effects of cyclophosphamide treatment on the expression of the receptors need to be further studied.

METHODS

We established different immune status in mice models with or without A. fumigatus infection. On days 1, 3 and 5 post inoculation, pulmonary tissues from mice of the different groups were harvested. Dectin-1 and TLR2 mRNA expression in the lungs of the mice were investigated by real-time PCR. The pulmonary fungal burden in the mice with A. fumigatus infection was also evaluated.

RESULTS

In the immunocompetent mice, three days after A. fumigatus inoculation, dectin-1 and TLR2 expression increased markedly compared with the normal control group. Cyclophosphamide inhibited the clearance of pathogens and the expression of dectin-1 with or without A. fumigatus infection in the lungs as well. There was no statistical difference in TLR2 expression between the different immune status groups.

CONCLUSIONS

Our results suggest that in vivo, dectin-1 and TLR2 are activated during the experimental period which would provide a broad range of possibilities for a specific and effective inflammatory response to kill A. fumigatus. Inhibition of dectin-1 expression may be one of the mechanisms of cyclophosphamide in the development of IPA.

Aspergillus fumigatus meningitis in immunosuppressed patients; diagnosis, management, prevention and control

Aspergillosis is a fungal disease that may be expressed by a diversity of clinical syndromes being produced by several of more than 170 Aspergillus species. The "Matei Balş" National Institute for Infectious Diseases has a long experience in diagnostic procedures and treatment of the immunosuppressed patients. Irrespective of the place of their residence, most patients with HIV infection and AIDS were investigated in the Institute in the last two decades. The first case of double central nervous infection (Mycobacterium tuberculosis and Aspergillus fumigatus) in a HIV positive patient is discussed.

Early NK cell-derived IFN-{gamma} is essential to host defense in neutropenic invasive aspergillosis

Invasive aspergillosis is among the most common human fungal infections and occurs in patients with severe and complex defects in immune responses. NK cells have previously been found to be important in host defense against this infection, but the mechanism of this effect is not known. We hypothesized that NK cells mediate their protective effect in invasive aspergillosis by acting as the major source of IFN-gamma during early infection. We found that, in the lungs of neutropenic mice with invasive aspergillosis, NK cells were the major population of cells capable of generating IFN-gamma during early infection. Depletion of NK cells resulted in reduced lung IFN-gamma levels and increased lung fungal load that was independent of T and B cell subsets. Depletion of NK cells and absence of IFN-gamma resulted in a similar increase in susceptibility to the infection, but depletion of NK cells in IFN-gamma-deficient hosts did not result in further increase in severity of the infection. NK cell-derived IFN-gamma caused enhanced macrophage antimicrobial effects in vitro and also resulted in greater expression of IFN-inducible chemokines in the lungs. Finally, transfer of activated NK cells from wild-type, but not IFN-gamma-deficient hosts, resulted in greater pathogen clearance from the lungs of both IFN-gamma-deficient and wild-type recipients. Taken together, these data indicate that NK cells are the main source of early IFN-gamma in the lungs in neutropenic invasive aspergillosis, and this is an important mechanism in the defense against this infection.

Fungal-Specific Humoral Response in Eosinophilic Mucus Chronic Rhinosinusitis

OBJECTIVES/HYPOTHESIS

An immunoglobulin (Ig)E-mediated allergic pathogenesis is presumed in allergic fungal sinusitis (AFS), yet extensive polyps and eosinophilic mucus (EM) in the paranasal sinuses may also occur in the absence of allergy. Although a noninvasive fungal pathogenesis is presumed in all chronic rhinosinusitis with EM (EMCRS), fungal-specific nonallergic immune responses have not been thoroughly investigated. We tested the hypothesis that there is a fungal-specific humoral response in EMCRS and that it is not confined to IgE.

STUDY DESIGN

EMCRS patients were prospectively stratified into subgroups based on the presence or absence of fungi within EM and of fungal-specific systemic IgE. There were 12 AFS, 5 AFS-like, 8 nonallergic fungal eosinophilic sinusitis (NAFES), and 5 nonallergic, nonfungal eosinophilic sinusitis (NANFES) patients.

METHODS

Alternaria alternata and Aspergillus fumigatus-specific serum IgE, IgG, IgM, and IgA was measured by enzyme-linked immunosorbent assay and compared with strictly defined healthy and disease-control groups.

RESULTS

Fungal-specific IgG (Alternaria alternata P = .0002; Aspergillus fumigatus P = .004), and IgA levels (Alternaria alternata P = .0016; Aspergillus fumigatus P = .002) were higher in EMCRS compared with healthy volunteers but not with disease controls. Fungal-specific IgG3 levels were significantly elevated in all the EMCRS subgroups compared with controls for either fungal antigen (P < .0001). Importantly, fungal-specific IgE levels were not significantly different between fungal-allergic EMCRS and disease controls.

CONCLUSIONS

Fungal-specific immunity characterized by serum IgG3 and not IgE, distinguished the EMCRS subgroups from control groups regardless of the presence of fungus within EM or of systemic fungal allergy. Fungal-specific IgE responses in fungal-allergic EMCRS were no different to those in fungal-allergic controls, thus challenging the presumption of a unique pathogenic role of fungal allergy in "allergic fungal sinusitis."

[Fungal (Candida) infections in the immunocompromised pediatric patient]

Today, mycotic infections in immunocompromised patients are mainly caused by Candida spp. and Aspergillus spp. The patients most sensitive to these infections are those with some kind of cell-mediated immunity quantitative or qualitative alteration (i.e., blood-related cancer, primary or secondary neutropenia, immunosuppressive disease or therapy, etc.). Candida infection in the immunosupressed patient comprises a wide range of serious diseases such as candidemia, chronic disseminated candididasis, endocarditis, meningitis and endophthalmitis. Therefore, infection by Candida spp. is considered secondary to the technological and medical advances which extend the life of patients with chronic diseases.

Galactomannan detection for invasive aspergillosis in immunocompromized patients

BACKGROUND

Invasive aspergillosis (IA) is the most common life-threatening opportunistic invasive mycosis in immunocompromized patients. A test for IA needs to be not too invasive and not too big a burden for the already weakened patient. The serum galactomannan ELISA seems to have potential for both requirements.

OBJECTIVES

To obtain summary estimates of the diagnostic accuracy of galactomannan detection in serum for the diagnosis of IA.

SEARCH STRATEGY

We searched MEDLINE, EMBASE and Web of Science with both Medical Headings and text words for both aspergillosis and the sandwich ELISA. We checked reference lists of included studies and review articles for additional studies.

SELECTION CRITERIA

Cross-sectional studies, case-control designs and consecutive series of patients assessing the diagnostic accuracy of galactomannan detection for the diagnosis of IA in patients with neutropenia or patients whose neutrophils are functionally compromised were included. The reference standard was composed of the criteria given by the European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed quality and extracted data

MAIN RESULTS

Thirty studies were included in the meta-analyses, with a median prevalence of IA (proven or probable) of 7.7%. Seven of these (901 patients) reported results for an Optical Density Index (ODI) of 0.5 as cut-off value. The overall sensitivity in these studies was 78% (61% to 89%) and overall specificity was 81% (72% to 88%). Twelve studies (1744 patients) reported the results for cut-off value of 1.0 ODI, overall sensitivity was 75% (59% to 86%) and mean specificity 91% (84% to 95%). Seventeen studies (2600 patients) reported the results for cut-off value 1.5 ODI, sensitivity was 64% (50% to 77%) and mean specificity 95% (91% to 97%).

AUTHORS' CONCLUSIONS

At a cut-off value 0.5 ODI in a population of 100 patients with a disease prevalence of 8% (overall median prevalence), 2 patients who have IA, will be missed (sensitivity 78%, 22% false negatives), and 17 patients will be treated or further referred unnecessarily (specificity of 81%, 19% false negatives). If we use the test at cut-off value 1.5 in the same population, that will mean that 3 IA patients will be missed (sensitivity 64%, 36% false negatives) and 5 patients will be treated or referred unnecessarily (specificity of 95%, 5% false negatives). These numbers should however be interpreted with caution, because the results were very heterogeneous.

Musculoskeletal manifestations and rheumatic symptoms in patients with cystic fibrosis (CF) no observations of CF-specific arthropathy

OBJECTIVE

To determine the character and frequency of musculoskeletal manifestations and rheumatic symptoms in patients with cystic fibrosis (CF).

METHODS

Rheumatic symptoms and signs of 70 patients with CF (age 6 to 61 yrs) were determined by interview and clinical assessment. Age and sex-matched healthy volunteers served as a control group. In CF patients, laboratory measures and bone mineral density (BMD) were investigated. The data were correlated with the CF phenotype [Shwachman Score (ShS), Chrispin-Norman Score (ChNS), and pulmonary function tests (PFT)].

RESULTS

The prevalence of joint pain in the CF patients was 12.9%, with a mean duration of 7 days. Swollen joints were found in 4 patients. None fulfilled the criteria for rheumatoid arthritis or connective tissue disease. Adult CF patients complained more often about noninflammatory back pain and myalgia, and demonstrated reduced spine mobility and impaired everyday life functions compared with the controls. Symptomatic CF patients had elevated erythrocyte sedimentation rate and C-reactive protein levels and performed worse on the ShS, ChNS, and PFT than asymptomatic patients. Antibodies against exotoxin A of Pseudomonas aeruginosa and recombinant Aspergillus fumigatus allergen f4 were found more frequently in CF patients with arthralgia. BMD was decreased in adult patients with more severe CF.

CONCLUSION

In CF patients, the prevalence of rheumatic symptoms increases with age and CF severity. Our data suggest an association of infections with P. aeruginosa and A. fumigatus with the occurrence of rheumatic symptoms. However, no association of CF with definite inflammatory joint or connective tissue diseases was observed, and no CF-specific pattern of musculoskeletal symptoms was seen.

Comparison of the value of measurement of serum galactomannan and Aspergillus-specific antibodies in the diagnosis of canine sino-nasal aspergillosis

Serology is currently used for the diagnosis of canine sino-nasal aspergillosis (SNA). However, the accuracy of serological testing using commercially available, standardized purified antigen preparations of Aspergillus (CAPurAspAg) has only been poorly documented. The aim of the present study was to assess the diagnostic value of an agar-gel double immunodiffusion (AGDD) test and an anti-Aspergillus IgG ELISA, using CAPurAspAg and the commercially available Platelia test for the detection of serum galactomannan. Sera from 17 dogs with SNA, 18 dogs with a nasal tumour (NT), 11 dogs with lymphoplasmacytic rhinitis (LPR) and 33 control dogs were tested with the 3 methods. AGDD result was positive in 76.5% of dogs with SNA, whereas all sera from dogs with non-fungal nasal disease and control dogs were negative. A positive IgG ELISA result was obtained in 88% of dogs with SNA and in 18% of dogs with LPR. All patients with NT and control dogs had a negative IgG ELISA result. The Platelia test was positive in 24% of dogs with SNA, 11% of dogs with NT, 9% of dogs with LPR and 24% of control dogs. The results of this study suggest that (1) the detection of serum Aspergillus-specific antibodies with AGDD or ELISA, using CAPurAspAg, provides excellent specificity and good sensitivity, (2) the specificity is higher for AGDD (100%) than for ELISA (96.8%) while sensitivity is higher for ELISA (88.2%) than for AGDD (76.5%) and (3) serum galactomannan quantification with the Plateliat test is unreliable for the diagnosis of canine SNA.

An aspergilloma caused by Aspergillus flavus

Chronic pulmonary aspergillosis is broad term encompassing chronic cavitary, chronic fibrosing pulmonary aspergillosis and aspergilloma. All affect patients with structural lung diseases and many have subtle genetic immune defects. Almost all cases are caused by Aspergillus fumigatus. Here we report a patient with an aspergilloma which had Aspergillus flavus recovered from a surgical specimen and serum containing detectable precipitating antibody.

[Significance of MUC5B antibody in differential diagnosis between Aspergillus species and Mucorales of fungal sinusitis]

OBJECTIVE

To differentiate between Aspergillus species and Mucorales of fungal sinusitis by immunohistochemistry.

METHODS

Formalin-fixed paraffin-embedded tissue blocks of 66 cases of fungal sinusitis were retrieved from the archival files of Department of Pathology of Beijing Tongren Hospital during the period from 2001 to 2006. The samples included 29 cases of fungal balls, 12 cases of allergic fungal sinusitis, 24 cases of chronic invasive fungal sinusitis and 1 case of acute invasive fungal sinusitis. The types of fungi were 44 Aspergillus species (31 cases of A. fumigatus, 7 cases of A. flavus and 6 cases of A. terreus) and 22 Mucorales (14 cases of Mucor species and 8 cases of Rhizopus species). Immunohistochemistry was performed with MUC2, MUC5AC and MUC5B antibodies. The results were compared with histochemical study for periodic acid-Schiff (PAS) and Grocott methenamine silver (GMS) stains.

RESULTS

Immunohistochemical study for MUC5B showed that the positive rate of Aspergillus species was 90.9%, in contrast to 4.5% in Mucorales (P < 0.001). The expression of MUC2 and MUC5AC was completely negative, whereas PAS and GMS stains were positive in all cases.

CONCLUSION

MUC5B antibody appears to be a useful immunohistochemical marker for identifying fungal types in tissue sections, especially in distinguishing between Aspergillus species and Mucorales in fungal sinusitis.

Primary cutaneous aspergillosis in a patient with a solid organ transplant: case report and review of the literature

GOAL

To understand primary cutaneous aspergillosis to better manage patients with the condition.

OBJECTIVES

Upon completion of this activity, dermatologists and general practitioners should be able to: 1. Describe risk factors for Aspergillus infection. 2. Identify diagnostic methods for primary cutaneous aspergillosis. 3. Discuss treatment options for primary cutaneous aspergillosis. Primary cutaneous aspergillosis is an uncommon disease in immunocompetent individuals that often affects immunosuppressed hosts. We present the first reported case of primary cutaneous aspergillosis in a solid organ transplant recipient caused by Aspergillus niger. Fruiting bodies were isolated from a necrotic ulcer arising in a surgical wound. Debridement alone failed to resolve the infection, emphasizing the need for early antifungal treatment combined with surgical management of this infection.

Provision of antifungal immunity and concomitant alloantigen tolerization by conditioned dendritic cells in experimental hematopoietic transplantation

FoxP3(+) regulatory T (Treg) cells are important mediators of peripheral tolerance, and deficiency of this population is associated with autoimmune inflammation and onset of acute lethal graft-vs.-host disease in transplantation. Type I IFN-producing plasmacytoid dendritic cells (pDC) are implicated in the induction and maintenance of tolerance and contribute to engraftment facilitation and prevention of graft-vs.-host disease after allogeneic hematopoietic stem cells transplantation (HSCT). Because host DC function is impaired during the immediate period post-transplant, the administration of donor DC may be useful for the educational program of recovering T cells. Distinct DC subsets could be derived from bone marrow (murine) or peripheral CD14(+) cell (human) cultures in the presence of either GM-CSF/IL-4 (myeloid DC) or FLT3-ligand (mainly pDC). The ability of either DC subset to induce Th1/Treg cell priming against Aspergillus fumigatus as well as the relative contribution of murine DC subsets to antifungal priming upon adoptive transfer in hematopoietic transplanted mice with aspergillosis is not known. We found specialization and complementarity in priming and tolerization by the different DC subsets, with FL-DC fulfilling the requirement for (i) Th1/Treg antifungal priming; ii) tolerization toward alloantigens and (iii) diversion from alloantigen-specific to antigen-specific T cell responses in the presence of donor T lymphocytes. Interestingly, thymosin alpha1 (Talpha1), known to modulate human pDC functions trough TLR9, affects mobilization and tolerization of pDC by activating the indoleamine 2,3-dioxygenase-dependent pathway, and this resulted in Treg development and tolerization. Thus, transplantation tolerance and concomitant pathogen clearance could be achieved through the therapeutic induction of antigen-specific Treg cells via instructive immunotherapy with pathogen- or TLR-conditioned donor DC.

Selective immunoglobulin M deficiency in an adult with Streptococcus pneumoniae sepsis and invasive aspergillosis

Primary selective immunoglobulin (Ig) M deficiency usually presents early in life with recurrent or severe infections caused by encapsulated and gram-negative organisms. Primary selective IgM deficiency in adults is rare and is usually associated with autoimmune diseases or malignant neoplasm. We performed an extensive immunological analysis of innate and adaptive immunity in an adult patient with possible primary selective IgM deficiency who presented with life-threatening Streptococcus pneumoniae septic shock and invasive Aspergillus fumigatus infection. The patient had no evidence of autoimmune disease or malignant neoplasm. Serum IgG, IgA, and IgE were normal; however, serum IgM levels and specific antibody titers against all 14 pneumococcal polysaccharide serotypes were consistently low. Complement CH50, C3, C4, and neutrophil phagocytosis and oxidative burst were normal. Toll-like receptor expression on monocytes was also normal. Therefore, adult patients with serious life-threatening and unusual infections should be investigated for possible selective primary IgM deficiency.

Role of neutrophils in preventing and resolving acute fungal sinusitis

Acute fungal sinusitis (AFS) is a devastating disease of the paranasal sinuses afflicting immunocompromised individuals. Knowledge about this disease is limited to clinical observations because there are no animal models in which to study the pathogenesis of the infection. Our goal was to develop a murine model of AFS and examine the role of neutrophils in host defense within the nasal cavity. Female C57BL/6 mice were depleted of neutrophils using anti-Gr-1 monoclonal antibody from day -1 to day 5 postinfection to initiate a transient neutropenia within the mice. At day 0, Aspergillus fumigatus conidia were administered intranasally. The untreated Aspergillus-exposed group had significant neutrophil recruitment by day 3, but by day 7 the leukocyte numbers had returned to unexposed levels. There was not a significant influx of mononuclear cells at either time point. In contrast, beginning at day 3 postinfection and continuing through day 7, anti-Gr-1-treated mice had increased cellular recruitment consisting of banded neutrophils at day 3 and mature neutrophils at day 7. Hyphal masses developed only in the anti-Gr-1-treated mice (25 to 36%) but only during the period of treatment. When the treatment was discontinued, hyphal masses could no longer be detected in the nasal cavities of these mice. In contrast, cyclophosphamide treatment did not induce neutropenia, and the nasal cavity remained free of hyphal masses. These studies demonstrate the feasibility of using this model to study AFS and implicate neutrophils in protection of the sinuses against acute Aspergillus infection and in clearance of established hyphal masses.

IL-23 and the Th17 pathway promote inflammation and impair antifungal immune resistance

Although inflammation is an essential component of the protective response to fungi, its dysregulation may significantly worsen fungal diseases. We found here that the IL-23/IL-17 developmental pathway acted as a negative regulator of the Th1-mediated immune resistance to fungi and played an inflammatory role previously attributed to uncontrolled Th1 cell responses. Both inflammation and infection were exacerbated by a heightened Th17 response against Candida albicans and Aspergillus fumigatus, two major human fungal pathogens. IL-23 acted as a molecular connection between uncontrolled fungal growth and inflammation, being produced by dendritic cells in response to a high fungal burden and counter-regulating IL-12p70 production. Both IL-23 and IL-17 subverted the inflammatory program of neutrophils, which resulted in severe tissue inflammatory pathology associated with infection. Our data are the first demonstrating that the IL-23/IL-17 pathway promotes inflammation and susceptibility in an infectious disease model. As IL-23-driven inflammation promotes infection and impairs antifungal resistance, modulation of the inflammatory response represents a potential strategy to stimulate protective immune responses to fungi.