Immunoblot analysis of serological responses in invasive aspergillosis

Uncoupling of invasive bacterial mucosal immunogenicity from pathogenicity

There is the notion that infection with a virulent intestinal pathogen induces generally stronger mucosal adaptive immunity than the exposure to an avirulent strain. Whether the associated mucosal inflammation is important or redundant for effective induction of immunity is, however, still unclear. Here we use a model of auxotrophic Salmonella infection in germ-free mice to show that live bacterial virulence factor-driven immunogenicity can be uncoupled from inflammatory pathogenicity. Although live auxotrophic Salmonella no longer causes inflammation, its mucosal virulence factors remain the main drivers of protective mucosal immunity; virulence factor-deficient, like killed, bacteria show reduced efficacy. Assessing the involvement of innate pathogen sensing mechanisms, we show MYD88/TRIF, Caspase-1/Caspase-11 inflammasome, and NOD1/NOD2 nodosome signaling to be individually redundant. In colonized animals we show that microbiota metabolite cross-feeding may recover intestinal luminal colonization but not pathogenicity. Consequent immunoglobulin A immunity and microbial niche competition synergistically protect against Salmonella wild-type infection.

Diagnostic Aspects of Chronic Pulmonary Aspergillosis: Present and New Directions

Purpose of Review

Diagnosis of chronic pulmonary aspergillosis (CPA) is important since many diseases have a similar appearance, but require different treatment. This review presents the well-established diagnostic criteria and new laboratory diagnostic approaches that have been evaluated for the diagnosis of this condition.

Recent Findings

Respiratory fungal culture is insensitive for CPA diagnosis. There are many new tests available, especially new platforms to detectAspergillusIgG. The most recent innovation is a lateral flow device, a point-of-care test that can be used in resource-constrained settings. Chest radiographs without cavitation or pleural thickening have a 100% negative predictive value for chronic cavitary pulmonary aspergillosis in the African setting.

Summary

Early diagnosis of CPA is important to avoid inappropriate treatment. It is our contention that these new diagnostics will transform the diagnosis of CPA and reduce the number of undiagnosed cases or cases with a late diagnosis.

Immunoproteomics of Aspergillus for the development of biomarkers and immunotherapies

Filamentous fungi of the genus Aspergillus play significant roles as pathogens causing superficial and invasive infections as well as allergic reactions in humans. Particularly invasive mycoses caused by Aspergillus species are characterized by high mortality rates due to difficult diagnosis and insufficient antifungal therapy. The application of immunoproteomic approaches has a great potential to identify new targets for the diagnosis, therapy, and vaccine development of diseases caused by Aspergillus species. Serological proteome analyses (SERPA) that combine 2D electrophoresis with Western blotting are still one of the most popular techniques for the identification of antigenic proteins. However, recently a growing number of approaches have been developed to identify proteins, which either provoke an antibody response or which represent targets of T-cell immunity in patients with allergy or fungal infections. Here, we review advances in the studies of immune responses against pathogenic Aspergilli as well as the current status of diagnosis and immunotherapy of Aspergillus infections.

Proteomic Profiling of Serological Responses to Aspergillus fumigatus Antigens in Patients with Invasive Aspergillosis

Aspergillus fumigatus is the species that most commonly causes the opportunistic infection invasive aspergillosis (IA) in patients being treated for hematological malignancies. Little is known about the A. fumigatus proteins that trigger the production of Aspergillus-specific IgG antibodies during the course of IA. To characterize the serological response to A. fumigatus protein antigens, mycelial proteins were separated by 2-D gel electrophoresis. The gels were immunoblotted with sera from patients with probable and proven IA and control patients without IA. We identified 49 different fungal proteins, which gave a positive IgG antibody signal. Most of these antigens play a role in primary metabolism and stress responses. Overall, our analysis identified 18 novel protein antigens from A. fumigatus. To determine whether these antigens can be used as diagnostic or prognostic markers or exhibit a protective activity, we employed supervised machine learning with decision trees. We identified two candidates for further analysis, the protein antigens CpcB and Shm2. Heterologously produced Shm2 induced a strongly proinflammatory response in human peripheral blood mononuclear cells after in vitro stimulation. In contrast, CpcB did not activate the immune response of PBMCs. These findings could serve as the basis for the development of an immunotherapy of IA.

Antibody testing in aspergillosis--quo vadis?

Humans are constantly exposed to airborne Aspergillus spores. Most develop Aspergillus-specific antibodies by adulthood. Persons with chronic lung disease or Aspergillus airway colonization often have raised levels of Aspergillus-specific immunoglobululin G (IgG). It is not known whether this signifies an increased risk of future aspergillosis.Chronic and allergic forms of pulmonary aspergillosis are estimated to affect over three million people worldwide. Antibody testing is central to diagnosis of these conditions, with raised Aspergillus-specific IgG in chronic pulmonary aspergillosis and raised Aspergillus-specific IgE in allergic aspergillosis. Antibody levels are also used to monitor treatment response in these syndromes. Acute invasive disease is less common. There is a more limited role for antibody testing in this setting as immunosuppression often results in delayed or absent antibody response.Many methods exist to detect Aspergillus-specific antibodies, but there are limited published data regarding comparative efficacy and reproducibility. We discuss the comparative merits of the available tests in the various clinical settings and their suitability for use in the resource-poor settings where the majority of cases of aspergillosis are thought to occur. We summarize the gaps in existing knowledge and opportunities for further study that could allow optimal use of antibody testing in this field.

Fungal heat-shock proteins in human disease

Heat-shock proteins (hsps) have been identified as molecular chaperones conserved between microbes and man and grouped by their molecular mass and high degree of amino acid homology. This article reviews the major hsps of Saccharomyces cerevisiae, their interactions with trehalose, the effect of fermentation and the role of the heat-shock factor. Information derived from this model, as well as from Neurospora crassa and Achlya ambisexualis, helps in understanding the importance of hsps in the pathogenic fungi, Candida albicans, Cryptococcus neoformans, Aspergillus spp., Histoplasma capsulatum, Paracoccidioides brasiliensis, Trichophyton rubrum, Phycomyces blakesleeanus, Fusarium oxysporum, Coccidioides immitis and Pneumocystis jiroveci. This has been matched with proteomic and genomic information examining hsp expression in response to noxious stimuli. Fungal hsp90 has been identified as a target for immunotherapy by a genetically recombinant antibody. The concept of combining this antibody fragment with an antifungal drug for treating life-threatening fungal infection and the potential interactions with human and microbial hsp90 and nitric oxide is discussed.

Follow-up of anti-Aspergillus IgG and IgA antibodies in bone marrow transplanted patients with invasive aspergillosis

A total of 89 patients at risk for, or with invasive aspergillosis (IA) were recruited from bone marrow transplantation (BMT) units in two Lisbon hospitals, and followed for 2(1/2) years to monitor their immune response. Of these patients, six developed probable IA, from which five died. The presence of serum IgG or IgA antibodies against seven Aspergillus recombinant antigens was assessed in patients with IA, using an enzyme-linked immunosorbent assay (ELISA). In parallel, the serum levels of galactomannan (GM) were also monitored, using the Platelia Aspergillus kit (Sanofi Pasteur, Marnes-la-Coquette, France). Superoxide dismutase (Sod) and 94 kDa were the most immunogenic antigens for IgA, while the IgG pattern of recognition changed from patient to patient. From our results we conclude that although follow-up of antibodies against these antigens should not be used as a diagnostic method, patients with IA do produce an immune response that may influence disease outcome.

Aspergillus fumigatus and aspergillosis

Aspergillus fumigatus is one of the most ubiquitous of the airborne saprophytic fungi. Humans and animals constantly inhale numerous conidia of this fungus. The conidia are normally eliminated in the immunocompetent host by innate immune mechanisms, and aspergilloma and allergic bronchopulmonary aspergillosis, uncommon clinical syndromes, are the only infections observed in such hosts. Thus, A. fumigatus was considered for years to be a weak pathogen. With increases in the number of immunosuppressed patients, however, there has been a dramatic increase in severe and usually fatal invasive aspergillosis, now the most common mold infection worldwide. In this review, the focus is on the biology of A. fumigatus and the diseases it causes. Included are discussions of (i) genomic and molecular characterization of the organism, (ii) clinical and laboratory methods available for the diagnosis of aspergillosis in immunocompetent and immunocompromised hosts, (iii) identification of host and fungal factors that play a role in the establishment of the fungus in vivo, and (iv) problems associated with antifungal therapy.

Immunoblotting patterns in the serodiagnosis of aspergilloma: antibody response to the 90kDa Aspergillus fumigatus antigen

At present there are no accepted criteria to assess the usefulness of Western blot assays for the serodiagnosis of aspergilloma. An Aspergillus fumigatus cytosolic fraction complex (CFC) composed of four proteins (p90, p60, p40, and p37) has been identified. The usefulness of Western blotting with CFC antigens for the serodiagnosis of aspergilloma was evaluated in 25 patients with well-established diagnoses and in 94 controls. The most consistently reactive antigen was p90 (92% of patients with aspergilloma), followed by p40 (76%) and the entire CFC taken together (76%). With these data, interpretive criteria for positive and negative immunoblots were established, with p90 indicated as a helpful marker of aspergilloma.

Specific antibody detection in invasive aspergillosis by analytical isoelectrofocusing and immunoblotting methods

Aspergillus fumigatus antigens have been tested to determine their potential as aids in the diagnosis of invasive aspergillosis (IA). Immunoglobulin G (IgG) antibodies to these antigens were detected by analytical isoelectrofocusing in conjunction with immunoblotting. A total of 12 antigenic fractions, including culture filtrates and surface and mycelial extracts of A. fumigatus, were investigated. Eleven were reactive with serum specimens from patients with aspergilloma, which served as positive controls for the evaluation of a specific IgG response. Eight of 12 antigens showed good responses with serum specimens from patients with allergic bronchopulmonary aspergillosis, which were used to assess the sensitivity of IgG detection. No measurable reactivity was detected in 18 negative control serum specimens, while 11 of 13 patients with proven, highly probable, or probable cases of IA had anti-Aspergillus IgG to multiple antigenic preparations. Patients with IA who were capable of mounting a substantial humoral response to Aspergillus antigens gave an antibody profile with five antigenic preparations which seemed to be characteristic of the disease. Data show that this method is highly sensitive and may allow the selection of fractions which are both highly antigenic and specific for the detection of antibodies to Aspergillus antigens. They also indicate that the use of a spectrum of antigenic molecules is advisable, given the variability observed in the immune responses of individual patients.

Pulmonary fungal infections in immunocompromised patients: incidence and risk factors

In a prospective study, 178 patients with fever > 38.4 degrees C and newly diagnosed pulmonary infiltrates underwent bronchoscopy with bronchoalveolar lavage (BAL), aspiration of bronchial secretions (BS) and, in 71 cases, protected specimen brushing (PSB). In 42/143 immunocompromised patients (haematological malignancies, n = 92; AIDS, n = 22; immunosuppressant therapy, n = 29) and in 4/35 patients with no defined underlying disease fungal pneumonia was present (candidosis, n = 35; aspergillosis, n = 8 mixed fungal infection, n = 3). Candidosis was combined, in 17 cases, with Aspergillus (n = 3), bacterial (n = 15) or cytomegalovirus (n = 2) infection. Aspergillosis was combined in eight cases with infection with Candida (n = 3), Pneumocystis carinii (n = 1) or bacteria (n = 5). The sensitivity of BAL and PSB in Candida pneumonia was 48% and 50%, respectively; specificity was 75% and 74% respectively. Bronchial secretions were more sensitive in detecting Candida pneumonia, but specificity was only 55%. In aspergillosis, the specificity of BAL, BS and PSB in each case was 100%; the sensitivity of BAL, BS and PSB was 38%, 64% and 100%. Twenty-four fungal infections were fatal. Unfavourable prognostic factors were respiratory failure needing mechanical ventilation, diffuse bilateral pulmonary infiltrates, mixed fungal infections and start of i.v. antifungal treatment > 14 days after fever onset, which were associated with a mortality rate of 74%, 67%, 67% and 63% respectively.

Obtenção e avaliação de antígenos de Aspergillus fumigatus

Antígenos de três amostras de A. fumigatus (354, 356, JIG) e antissoro contra a mistura destes antígenos foram produzidos e avaliados imunoquimicamente. Os antígenos de filtrado de cultura foram obtidos após concentração com acetona conforme adaptação da técnica descrita por Coleman & Kaufman. Em prova de ID obteve-se 100% de positividade com os soros de pacientes com aspergilose estudados. Com relação aos soros heterólogos encontramos reatividade com soro de um paciente com candidíase e com soro de um paciente com histoplasmose; foi encontrado padrão idêntico de resposta quando se utilizou o antígeno de referência. O antissoro foi titulado por ID, CIE e RFC MI contra o antígeno específico apresentando títulos respectivos de 1:32, 1:32 e 1:128, e utilizado para reagir contra o mesmo antígeno por IEF, demonstrando 8 linhas de precipitação, sendo 5 na região anódica e 3 na região catódica. O perfil de bandeamento do antígeno em eletroforese utilizando gel de poliacrilamida (SDS-PAGE) a 12,5% apresentou-se complexo com 26 sub-unidades protéicas, cujos pesos moleculares variaram de 18 a > 100kDa. Quando estes componentes foram eletrotransferidos e reagidos com o antissoro específico ("immunoblotting"), verificou-se imunogenicidade em todas as frações bandeadas.

Isolation and antigenicity of a 45-kilodalton Paracoccidioides brasiliensis immunodominant antigen

In the present study, we analyzed human antibody responses to Paracoccidioides brasiliensis cellular antigens by the immunoblot technique to identify specific cellular components and to investigate the existence of antigen profile differences among serological responses of paracoccidioidomycosis (PCM) patients. Among the 64 PCM serum samples analyzed, a relatively homogeneous immunoglobulin G response to P. brasiliensis antigens was observed. The polypeptide with a mass of 45 kDa was the most clinically important, since antibody to this antigen was detectable in 90.6% of PCM patients studied and the six individuals who did not produce antibody were either at the end of treatment or in the posttherapy period and had shown clinical recovery. These facts suggested that the presence of this antibody may be an indicator of active disease. The 45-kDa antigen was also the most specific antigen of the PCM humoral immune response, since it reacted with only 2 of 79 (2.5%) heterologous serum samples tested: 1 histoplasmosis case and 1 tuberculosis case. This polypeptide was isolated from gels by electroelution and, when tested by an immunoradiometric assay and immunoblotting, maintained its reactivity with PCM sera and also with anti-P. brasiliensis polyclonal antibodies raised in rabbits at the same sensitivity levels as those obtained in immunoblotting with a crude antigen. Since in our assays the 45-kDa polypeptide was the major P. brasiliensis antigen and seemed to be specific for PCM, its use in alternative diagnostic methods is promising, especially in patients suspected of having the juvenile clinical form of PCM often associated with negative double-immunodiffusion results.

Antigen detection in invasive aspergillosis

The application of a reverse passive latex agglutination test and dot-blot assay are reported in the diagnosis of 50 proven cases of invasive aspergillosis and 28 suspected cases. At a latex titre cut off of greater than or equal to 1 in 8 the test had a sensitivity of 29.4%, specificity of 96.3% and efficiency of 41.4%. This was in sera taken when the diagnosis was first suggested. The sensitivity rose to 55.1% when sera with the maximum level of antigen were examined. The dot blot was more sensitive with 33.3% of cases being positive in the initial sera. This increased to 61.5% when the serum with the maximum antigen level was taken.

Heat shock protein 88 and Aspergillus infection

Immunoblotting was used to dissect the antibody responses in the sera of 50 patients with proven invasive aspergillosis, 28 patients with suspected invasive aspergillosis, 35 patients with allergic bronchopulmonary aspergillosis, and 10 patients with an aspergilloma. This demonstrated the immunodominance of antigenic bands at 88, 84, 51, and 40 kDa. Monoclonal antibodies against the heat shock protein 90 complexes of Candida albicans and the water mold Achlya ambisexualis identified these four antigenic bands as homologous proteins. Similar antigens have been described in humans, mice, Saccharomyces cerevisiae, chickens, and Drosophila species. The antibody against A. ambisexualis has previously been shown to cross-react with antigens belonging to the human heat shock protein 90 complex. Aspergillus heat shock protein 90 was extracted from the sera of patients with invasive aspergillosis by affinity chromatography. This was done with both a rabbit hyperimmune antiserum raised against an extract of Aspergillus fumigatus NCPF 2109 and a monoclonal antibody against the heat shock protein 90 of C. albicans. In vivo expression of the antigen was demonstrated in an aspergilloma surgically removed from a patient. The role of the antigen as an allergen in allergic bronchopulmonary aspergillosis is also discussed.

Immunodiagnosis of aspergillosis

Aspergillus species are ubiquitous fungi and have been implicated as the causative agents of a variety of lung disorders in humans. These disorders include allergic, saprophytic, and systemic manifestations. The allergic disorders mainly affect atopic persons, and invasive or systemic diseases affect immunosuppressed individuals. Immunodiagnosis can help the practitioner diagnose these diseases. Demonstration of circulating antibodies is a useful criterion, but the lack of dependable and standardized antigens is a limiting factor in the diagnosis of most Aspergillus-induced diseases. Despite this limitation, however, immunodiffusion and enzyme-linked immunosorbent assays have been widely used for the detection of antibodies in the sera of patients with aspergillosis. Similarly, crude and semipurified antigens are being used to demonstrate skin hypersensitivity in patients, and several methods have been useful in the detection of antigenemia in patients with invasive aspergillosis. With a growing number of reports on the incidence of aspergillosis and an increase in the number of immunosuppressed individuals in the population, more rapid methods and more reliable reagents for immunodiagnosis are needed. With recent attempts at obtaining reliable reagents for through hybridoma technology and molecular biological techniques, substantial progress toward efficient immunodiagnosis may be achieved.

Identification and characterization of an immunodominant 58-kilodalton antigen of Aspergillus fumigatus recognized by sera of patients with invasive aspergillosis

Sera from 38 patients with invasive aspergillosis were tested by Western immunoblotting for the presence of antibodies to antigens of Aspergillus fumigatus present in a mycelial extract of the organism. All of the sera contained antibodies to an antigen of molecular weight 58,000, which was which was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was the only antigen recognized in approximately 90% of the sera tested. The 58-kDa antigen is an abundant component of mycelial extracts composing approximately 50% of the Coomassie blue-stained protein. The antigen also contains carbohydrate, since it is stained by the carbohydrate stain periodic acid-Schiff and it binds to the lectin concanavalin A. It was purified by immunoaffinity chromatography employing a monoclonal antibody directed against an epitope on the 58-kDa antigen. Analysis of the purified antigen by gas-liquid chromatography revealed the presence of mannose, galactose, and glucose residues in a 2:1:2 ratio. The ratio of protein to carbohydrate is 1.16:1. The protein is slightly acidic, containing relatively high quantities of glutamic and aspartic acids, glycine, alanine, serine, and threonine. The 58-kDa antigen also contains phosphate groups as part of its structure. Serological activity was totally destroyed after treatment with sodium metaperiodate and was partially destroyed after treatment with pronase. The 58-kDa antigen was not able to hydrolyze protein.

Use of immunoblotting to detect Aspergillus fumigatus antigen in sera and urines of rats with experimental invasive aspergillosis

Immunoblotting was used to detect Aspergillus fumigatus antigen in sera and urines of immunosuppressed rats experimentally infected with A. fumigatus. Organisms were administered by both intravenous and intratracheal injections. Intravenously infected rats developed disseminated aspergillosis, but intratracheally infected rats developed pulmonary disease only. Fungal cultures of blood and urine samples from infected rats were negative. In the urines of intravenously infected rats, antigen was detected 24 to 48 h after infection; in the urines of intratracheally infected animals, antigen was detected on days 4 to 5 after infection. Antigen in serum was detected later than antigen in urine was. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of serum and urine samples, the most strongly reacting antigenic materials were found in the 88-, 40-, 27-, and 20-kilodalton regions. These dominant antigens appeared to be the same as those of control antigens prepared from A. fumigatus grown in vitro. Rabbit antiserum to Aspergillus filtrate antigen was found to be more immunoreactive than antiserum to mycelial or conidial antigen. No mycelium-specific antigens were detected.

Prophylaxis of fungal infections with itraconazole during remission-induction therapy

Deep fungal infections are an increasing problem in the treatment of acute leukemias and malignant lymphomas. Risk factors are known but unavoidable. Because of diagnostic difficulties most patients are treated empirically with intravenous amphotericin B. This drug's toxicity increases morbidity and mortality. An orally absorbable triazole derivative, itraconazole, may offer effective and safe prophylaxis against deep candidosis and aspergillosis in these patients. Such infections have been treated successfully with oral itraconazole even when resistant to intravenous amphotericin B. In retrospective comparative studies there are significantly less deep fungal infections in patients given itraconazole. The significance of the difference varies between studies. Pharmacokinetic data confirm therapeutic plasma levels of itraconazole but with wide variation within and between patients. The current large, multi-centre, randomised, double-blind, prospective trial of oral itraconazole versus placebo in the U.K. will test its prophylactic efficacy against deep fungal infections during treatment of haematological malignancies.

Serological techniques for diagnosis of fungal infection

This review summarizes recent developments in the serodiagnosis of candidiasis, aspergillosis, cryptococcosis, histoplasmosis, blastomycosis, coccidioidomycosis, mucormycosis and sporotrichosis. A number of studies have substantiated the presence of circulating antigens in invasive candidiasis, invasive aspergillosis, disseminated histoplasmosis and coccidioidomycosis, and immunoassays for antigen detection provide moderate sensitivity but high specificity for disease. Improved detection may result mainly from repeated serum or concentrated urine samplings rather than from the development of more sensitive immunoassays. Immunoblot analysis of the serological response is a useful tool for the identification of immunogenic fungal components that elicit a specific antibody response in invasive disease. This method, and others, have been successfully applied to the study of the immune response to several fungi, including Candida, Aspergillus and Rhizopus.

Immunoblot fingerprinting Aspergillus fumigatus

A new technique for typing Aspergillus fumigatus is presented. This is based on immunoblot fingerprinting each isolate against a rabbit hyperimmune antiserum raised against A. fumigatus NCTC 2109. All isolates were typable and reproducibility for the 16 antigenic bands which formed the basis of the system was excellent. Discrimination was better than silver staining and revealed 11 types among the 21 isolates from eight patients with an aspergilloma. Each aspergilloma could be due to either a single or multiple types.

Immunoblot analysis of antibody responses to Sporothrix schenckii

The serologic response to Sporothrix schenckii was investigated in patients with sporotrichosis by solid-phase enzyme-linked immunosorbent assays (ELISAs) and Western immunoblot techniques. A soluble antigen preparation derived from an S. schenckii isolate contained 15 protein staining components ranging in molecular size from 22 to 70 kilodaltons (kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Sera from 40 patients with sporotrichosis demonstrated Sporothrix immunoglobulin G antibody by ELISA with titers between 128 and 65,200. No sera from 300 healthy individuals or 100 patients with various systemic mycoses other than sporotrichosis had ELISA titers greater than 64. By Western immunoblotting of the antigens separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, sera from 10 patients with cutaneous sporotrichosis reacted with 8 to 10 antigen components (range, 40 to 70 kDa), while sera from 15 patients with extracutaneous sporotrichosis reacted with a greater number of antigen components (15 to 20 bands) over a wider range of molecular sizes (22 to 70 kDa). Antibody to 40- and 70-kDa antigen components was detected by immunoblots in all sera tested from patients with sporotrichosis. Antibody to 22- to 36-kDa antigen components was present in sera from 13 of 15 patients with extracutaneous sporotrichosis, but these lower-molecular-weight components were not detected by sera from patients with cutaneous sporotrichosis. Antibody to these components was not detected by Western blotting in sera from 19 of 20 patients with other fungal diseases or from 30 healthy individuals. Purification of these specific antigen fractions could provide the basis of a sensitive and specific serodiagnostic test to indicate the presence and activity of extracutaneous sporotrichosis.

Structural analysis of water-soluble fractions obtained from Aspergillus fumigatus mycelium

Fractions were prepared from the water-soluble components of Aspergillus fumigatus mycelium either by lectin-affinity chromatography or salt precipitation. While they varied considerably in their amino-acid composition, each contained a preponderance of aspartic and glutamic acids. 13C-NMR spectroscopy of these fractions, compared with that of polysaccharide obtained by alkaline extraction, indicated the presence of glycoproteins, the polysaccharide components of which contained beta-D-Galf units that are part of structures chemically different from those obtained by alkali treatment. In two of the three fractions examined, gas-liquid chromatography--mass spectrometry showed marked differences in the contents of non-reducing end-units of alpha-D-Manp and beta-D-Galf. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the preparations revealed an array of components, which stained to differing extents with silver stain and with Coomassie Blue and many of which were bound by lectins with specificity for different sugars.

Invasive pulmonary aspergillosis of horses: an association with acute enteritis

Invasive pulmonary aspergillosis was identified in 19 horses. In 16 cases mycotic lesions were associated with enterocolitis; 14 cases appeared to result from Salmonella infection. Pulmonary lesions included multifocal areas of acute necrosis, leukocytoclastic vasculitis, and thrombosis with fibrinosuppurative inflammation surrounding mycelial masses. Thromboemboli with fungi were in the brain and kidneys of three cases. Factors which appeared to predispose to pulmonary aspergillosis included corticosteroid therapy, disseminated neoplasms, hepatitis, pleuritis, and peritonitis. This study suggests that immunocompromise and invasion of Aspergillus sp. from damaged intestine are more important in causing equine pulmonary aspergillosis than inhalation of spores.

Apparent pulmonary mycetoma following invasive aspergillosis in neutropenic patients

After the death from massive haemoptysis of two neutropenic patients who had developed apparent pulmonary mycetomas, two subsequent patients underwent successful resection of similar lesions. Histological examination of these lesions confirmed that these so called mycetomas were masses of devitalized lung tissue infiltrated with fungus. The term mycotic lung sequestrum is therefore proposed to distinguish this condition from a fungus ball arising in a previously formed cavity. A review of 34 similar cases reported previously showed that haemoptysis occurred in about half of the cases and was fatal in just over half of these. Medical treatment appears to have little impact on survival and early consideration of surgical intervention is important.

Pathogenetic and serological aspects of pulmonary aspergillosis

Af is an important pathogen of the bronchopulmonary system, and the clinical spectrum encompasses aspergilloma, CNPA, IPA, ABPA, bronchial asthma, and allergic alveolitis. Bronchial carriage may, however, not always be associated with pathological effects. The polymorphism of the aspergillus-related disorders seems mostly to depend upon the different responses of the hosts. This review considers the antigenic composition of Af and specific antibody responses in man in relation to the pathogenesis and diagnosis of the various forms of pulmonary aspergillosis. More than 200 macromolecular components have been listed for Af and more than 30 antigens found to react with human sera. Serum antibodies to Af are common in healthy subjects. Schønheyder and his associates (A-L) have shown that IgG, IgA and IgM antibodies in healthy subjects are directed towards antigens to which also patients with aspergillosis strongly react. With immunofluorescent staining these antigens were found to be associated with hyphal walls, and a MW 470,000 fraction from ruptured mycelium was most reactive in ELISA. The respiratory tract appears to be the major route for exposure since the humoral responses include IgA class antibodies, and sIgA antibodies are found in bronchial secretions. Moreover, IgG antibody levels to the MW 470,000 fraction correlate with occupational exposure and smoking habits. In patients with cystic fibrosis high IgG antibody levels to MW 470,000 and MW 25,000-50,000 antigen fractions were associated with the carriage of Af in the sputum. An individual patient's level of IgA antibodies to the MW 470,000 fraction was inversely related to the Af carrier rate, and this was also true for IgE dependent reactivity to Af antigens. These observations indicate that IgG antibodies to some antigens mirror the extent of antigenic exposure, whereas some IgA and IgE antibodies may play a protective role against bronchial colonization with Af. IgG antibody determinations by ELISA were found to provide a higher diagnostic efficacy in pulmonary aspergillosis than IgA antibody assays. With IgG antibodies there were statistically significant differences between patients and the controls and there was little overlap of ELISA values between the groups. The fractions of MW 250,000 with catalase activity and MW 25,000-50,000 with protease activity, were most suitable for serological diagnosis. A gel immunoelectrophoretic assay proved Af catalase to be a major diagnostic antigen in patients with aspergilloma or with an apical aspergillus lung infiltrate.(ABSTRACT TRUNCATED AT 400 WORDS)