Significance and interpretation of laboratory tests in pulmonary aspergillosis

Between-laboratory quality control of automated analysis of IgG antibodies against Aspergillus fumigatus

Measurement of IgG antibodies against Aspergillus fumigatus is an important criterion for the diagnosis of aspergilloma, allergic bronchopulmonary aspergillosis, and extrinsic allergic alveolitis. In the present study, we compared IgG antibody analysis against A. fumigatus using 2 widely used automated immunochemistry systems. In a between-laboratory quality control program, good agreement was found between the results from laboratories that used the ImmunoCAP system; however, a laboratory that used the Immulite 2000 system found approx. 2-fold higher antibody levels in the quality control samples than did the ImmunoCAP system. Measurements of IgG against A. fumigatus in patient sera were significantly correlated (r(s) = 0.77, P < 0.0001). These results demonstrate that analysis of IgG antibodies against A. fumigatus with these 2 systems has reached a level of standardization that allows for direct comparison of quantitative results from different laboratories. For longitudinal analysis of IgG against A. fumigatus, reagents from the same manufacturer should be used.

Development of a chromosomal DNA probe for the laboratory diagnosis of aspergillosis

Chromosomal DNA was extracted from clinical isolates of Aspergillus fumigatus of human and animal origin using the protoplast lysate method. The probe was developed by the nick translation of the chromosomal DNA genome fraction with p32 as the radiolabel. Hybridization of the probe with endonuclease-cleaved DNA of the same species resulted in a pattern of recognition sites specific for the species. The latter was not seen in other species encountered in clinical specimens. Trials were carried out on sputum experimentally inoculated with the fungus where crude DNA was directly extracted, treated with the endonuclease and hybridized with the probe. The efficacy of the probe was as good with the crude as the purified DNA. The specificity of the probe was determined by testing it against single and mixed DNA populations extracted from different species of several fungal and bacterial genera isolated from and/or known to occur in clinical specimens of respiratory infection origin. The sensitivity of the probe was assessed by detecting a DNA concentration in the specimen equivalent to 3 C.F.U.

Pseudoepidemic of aspergillosis after development of pulmonary infiltrates in a group of bone marrow transplant patients

During February and March 1985, seven patients in the pediatric bone marrow transplant unit (PBMTU) of a 350-bed cancer hospital developed pulmonary infiltrates. Five of the patients had Aspergillus spp. isolated from the respiratory tract, and two of these patients had histologic evidence of aspergillosis. Between 26 February and 22 April, Aspergillus spp. were isolated in a total of 70 cultures from 39 hospitalized patients. Of the 70 cultures, 14 (group 1) were from respiratory specimens of PBMTU patients with pulmonary infiltrates and were submitted to the laboratory intermittently over the 56-day period. However, of the other 56 Aspergillus-positive cultures (group 2), 41 (73%) were submitted on six days during this period (P less than 0.001, chi-square goodness of fit), including 8 blood cultures submitted on one day. When Aspergillus sp. was recovered from group 1 cultures early during this period, the isolates were stored in the culture-processing room. Aspergillus isolates were not handled in a biological safety cabinet, and blood cultures were done by using a system which requires opening of an evacuated bottle to room air. The presence of stored Aspergillus isolates was associated with a markedly elevated concentration of airborne fungi in the culture-processing room. After removal of the stored Aspergillus isolates from the culture-processing room, the concentration of airborne fungi returned to background level and there were no further Aspergillus-positive cultures. These findings suggested that group 2 cultures had been contaminated by stored Aspergillus isolates. No evidence for a common source of infection was found in the PBMTU patients with pulmonary infiltrates.

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)

Management of pulmonary aspergilloma in the presence of active tuberculosis

Eleven cases of pulmonary aspergilloma complicating active cavitating pulmonary tuberculosis are reviewed. Nine of the 10 patients who had combined medical (antituberculosis drugs) and surgical treatment were cured of their disease; one patient, who had bilateral multiple aspergillomas, died from massive haemoptysis after resection of one of the affected lobes. The only medically treated patient who refused surgery had fatal haemoptysis at home. Pulmonary resection is recommended for patients who are fit for operation whenever the diagnosis of aspergilloma is made because most published reports indicate that only a few patients benefit from drug treatment alone.

Aspergillosis in 25 renal transplant patients. Epidemiology, clinical presentation, diagnosis, and management

In immunocompromised renal transplant patients, aspergillosis can be a life-threatening opportunistic infection. During an 8-year period, 25 renal transplant recipients at the University of Minnesota Hospitals developed unequivocal invasive aspergillosis that occurred in epidemic-like patterns in immunocompromised patients throughout the hospital. The premortem diagnosis was made in only 14 of the 25 patients. Seventeen patients died, and three of the eight survivors lost their allografts. The prognosis was dependent upon the clinical pattern of illness: three clinical patterns emerged: (1) cavitary lung disease, (2) diffuse pulmonary disease, and (3) central nervous system disease. All patients in the latter two categories died. The best results were with those patients treated with both amphotericin B and excision of cavitary lung lesions. All three patients treated in this manner survived with functioning grafts. Traditionally, sputum cultures have been thought to be unreliable because Aspergillus is a common colonizer of the upper respiratory tract and a contaminant in laboratories. In this study, false positive sputum cultures were common. A positive sputum culture can be helpful, however, all patients with two positive sputum cultures proved to have invasive aspergillosis. In addition, 86% of patients with positive sputum cultures who were clinically ill proved to have invasive infection. Bronchoscopy is a useful technique to follow up a positive sputum culture or investigate negative sputum cultures with typical clinical patterns. Routine bronchoscopy, unfortunately, also yields a high incidence of false positive cultures. Since the use of covered brush bronchoscopy technique, however, no false positive transbronchial cultures have been found. Transbronchial biopsy is a useful adjunct and is proof of the presence of invasive disease when the results are positive. However, false negative results are also found. Overall, the highest diagnostic yield is obtained both with transbronchial lung biopsy and covered brush bronchoscopy culture. All eight patients with both these procedures were correctly identified as having invasive pulmonary aspergillosis.

Rapid enzyme-linked immunosorbent assay (ELISA) for Aspergillus fumigatus antibodies

A rapid enzyme-linked immunosorbent assay (ELISA) where component incubation periods were shortened to one hour, was compared with agar gel double diffusion (AGDD) and a standard ELISA procedure for detecting antibodies to Aspergillus fumigatus in 28 asthmatic patients with suspected allergic aspergillosis. Using two A fumigatus antigens the rapid ELISA compared well with AGDD and the standard ELISA method. Eleven sera that reacted with both antigens in AGDD were all positive against antigen 1 in both forms of ELISA, but two failed to react with antigen 2 in the standard ELISA and three failed to react with this antigen in the rapid method. Thirteen AGDD-negative sera were also negative in both forms of ELISA. The rapid ELISA provides a sensitive and reproducible test for routine serological investigation of allergic aspergillosis.

A guide to the recent literature on aspergillosis as caused by Aspergillus fumigatus, a fungus frequently found in self-heating organic matter

Spores of Aspergillus fumigatus have been found to be abundantly present in the outdoor air at a site where large scale experimental composting of sewage sludge is in progress at Beltsville, Maryland. The health significance of this finding, for that site and for others in the future, is still only incompletely understood. Further studies are in progress to characterize absolute concentrations of the spores of the fungus in air at the site, spore dispersal by air from composting operations, and background environmental spore levels in air. The present paper contains a list of references to papers on health effects of A. fumigatus, many published in the past ten years, along with a review of the same designed to assist the reader in finding information on particular aspects of the subject in the literature. It is intended primarily as an aid to individuals interested in sludge composting and wishing to attain an insight into the A. fumigatus-composting situation, but it may also interest others concerned with other substrates which become moldy at 40--50 C. A. fumigatus has been found in great numbers in naturally and artificially heated environments such as decaying leaves, compost heaps, solar heated sloughs, cooling canals for nuclear power generators, silos, grain storage bins, boiler rooms, detritus around steam turbines and sauna baths. The evident practical merits of sludge composting have been described elsewhere; the information presented here has its main significance in respect to requirements for choice of locations for composting sites and to process and design criteria.

Immunologic monitoring and aspergillosis in renal transplant patients

Three cases of pulmonary aspergillosis in a "high risk" population of renal transplant recipients are presented. The source of infection was traced to the forced air exhaust system of the Transplantation Unit. Early definitive diagnosis of the infection was very important for effective management. Immunologic monitoring was demonstrated to be instrumental in indicating the early presence of infection, and as a guideline to reduced immunosuppression during therapy. Bronchoscopy with brushings and endobronchial cavitary biopsy were valuable methods for obtaining the infected tissue. Amphotericin B was effective when therapy was started early. Adequate levels of the drug were obtained by varying the dose and frequency of administration according to serum inhibitory titers. Control of infection was aided by immunologic monitoring at regular intervals.

Use of the immunodiffusion test in the serodiagnosis of aspergillosis

The diagnostic value of an immunodiffusion (ID) test with standardized precipitinogens derived from five Aspergillus species was determined with sera from 60 proven and 12 suspected cases of aspergillosis. The data demonstrated that the greatest number of aspergillosis cases were detected by the concurrent use of A. fumigatus and A. niger precipitinogens. With these precipitinogens, the ID test permitted the serodiagnosis of aspergillosis in 82% of the 60 proven cases and in 83% of the 12 suspected cases. The presence of one or more precipitins was indicative of aspergilloma, of allergic bronchopulmonary aspergillosis, or of invasive aspergillosis. Precipitins were detected in 93% of the sera from patients with aspergilloma, in 50% of the sera from patients with allergic bronchopulmonary aspergillosis, and in 88% of the sera from patients with invasive aspergillosis. Although the presence of one or two precipitin bands could indicate any form of aspergillosis, the presence of three or four was strong evidence of either aspergilloma or invasive aspergillosis. The ID test was found to be 100% specific in an evaluation of its effectiveness with 65 sera from individuals with other systemic mycotic infections, bacterial or neoplastic diseases, and from apparently normal humans. In diagnosed cases of aspergillosis, the examination of serial serum specimens provided information about the clinical course of the disease. A reduction in the number of precipitin bands and significant titer changes were noted as the patients responded to therapy.

Necrotizing pulmonary aspergillosis

Necrotizing or invasive aspergillary infection of the lungs has previously been considered a rare condition affecting only the debilitated or seriously ill. Four patients with necrotizing pulmonary aspergillosis are described, and the mycological and histopathological findings are discussed. The diagnosis in the first patient was not made until necropsy, following death from fulminating pulmonary infection. Of three patients treated with natamycin, two made a satisfactory recovery; the other died later from bronchial carcinoma. Previous multiple antibiotic therapy in each case may have been a contributory factor to infection with Aspergillus fumigatus. We suggest that fungal infection of the lungs should be actively sought in patients with pulmonary disease, especially in those receiving multiple antibiotic or corticosteroid therapy.

Allergic aspergillosis: review of 32 cases

The clinical, radiographic, and laboratory findings have been reviewed in a series of 22 patients with definite and 10 with probable allergic aspergillosis. Episodes of segmental shadowing occurred most frequently in the upper lobes and tended to recur in the same segment. Radiologically visible mucoid impaction of a large bronchus was demonstrated in eight cases, and saccular bronchiectasis in six cases, in the affected segments. Two patients have recovered, eight continued to experience episodic symptoms and shadows for up to 13 years, and 11 are on steroid therapy with relief of airways obstruction and prevention of further lung shadows. Four, together with five others who probably represent a late stage of the disease, have upper lobe contraction. One patient developed aspergillomas and one died with invasive aspergillosis. Sputum has remained positive in all except one patient. Precipitins were present in all cases. They varied widely in strength and appeared to be more closely related to the amount of antigenic exposure than to the severity of the allergic manifestations. Allergy to Aspergillus fumigatus probably plays a dominant role in the symptomatology of those with asthma of late onset; evidence of underlying atopic diathesis and of increased spore exposure could usually be adduced in these patients. A quantitative interaction of atopic diathesis and contact with a growing source of fungal antigens will result in a locally florid bronchial reaction, with plugging and subsequent dilatation. The peripheral shadows are consistent with areas of collapse distal to bronchial occlusion. The frequency and distribution of mucoid impaction found in this series suggest that allergic aspergillosis may be a major cause of this uncommon syndrome, which could represent an exaggerated form of bronchial plugging.

Pulmonary aspergillosis. A survey of its occurrence in patients with chronic lung disease and a discussion of the significance of diagnostic tests

The occurrence of pulmonary aspergillosis and of precipitins, positive skin tests, and sputum containing abundant Aspergillus fumigatus has been assessed and correlated in a survey of 107 consecutive patients attending hospital in Bristol with various chronic chest diseases. The series included three with aspergilloma, five with allergic aspergillosis, and one with chronic invasive aspergillosis. Of 46 asthmatic patients, 11% had definite and 22% had probable or definite allergic aspergillosis.

Seven patients (15%) in the asthmatic group were found to have chronic upper lobe contraction, probably attributable to long-standing allergic aspergillosis. One of these patients developed aspergilloma, and another, invasive aspergillosis.

The significance of precipitins is discussed, based on the survey patients together with 21 additional patients who had aspergillosis but were from outside the survey. In the survey patients without definite aspergillosis, precipitins and positive sputum were significantly associated and were found most commonly in patients with asthma, bronchiectasis, or cavitated lungs. Two patients with invasive aspergillosis who had weak precipitins are reported. We think that precipitins reflect recent or continuing fungal growth in body tissues or within damaged bronchi, and that their presence can be a useful indication of occult fungal colonization, which might rarely become invasive if host resistance were lowered as by steroids.

Allergic aspergillosis is a more common condition and a more frequent cause of upper lobe damage than has been appreciated.