Galactomannan and computed tomography-based preemptive antifungal therapy in neutropenic patients at high risk for invasive fungal infection: a prospective feasibility study

BACKGROUND

Empirical antifungal therapy is the standard treatment for persistent or relapsing antibiotic-resistant neutropenic fever. However, overtreatment resulting in increased toxicity and treatment-related cost is a major shortcoming of such therapy. We assessed the feasibility of a "preemptive" approach based on the incorporation of sensitive, noninvasive diagnostic tests for consecutive high-risk neutropenic patients who had received fluconazole prophylaxis while avoiding empirical therapy.

METHODS

A total of 136 treatment episodes for persons who were at risk of acquiring invasive fungal infection (IFI) were screened for the presence of galactomannan with an enzyme immunoassay. A diagnostic evaluation, which included thoracic computed tomography scanning (HRCT) and bronchoscopy with lavage, was performed on the basis of well-defined clinical, radiological, and microbiological criteria. Only seropositive patients and patients with a positive microbiological test result plus supportive radiological findings received liposomal amphotericin B.

RESULTS

Neutropenic fever developed in 117 episodes, of which at least 41 episodes (35%) satisfied existing criteria for empirical antifungal therapy. However, our protocol-driven preemptive approach reduced the rate of antifungal use for these episodes from 35% to 7.7% (a 78% reduction) and led to the early initiation of antifungal therapy in 10 episodes (7.3%) that were clinically not suspected of being IFI. No undetected cases of invasive aspergillosis were identified; 1 case of zygomycosis was missed. Breakthrough candidemia was diagnosed by conventional culture techniques and was treated successfully. With use of a preemptive approach, the 12-week survival rate for patients with IFI was 63.6% (it was 63.1% for those with invasive aspergillosis).

CONCLUSION

Preemptive therapy based on enzyme immunoassay and HRCT reduced the exposure to expensive and potentially toxic drugs and offered effective antifungal control, but it failed to detect non-Aspergillus IFI.

Detection of circulating galactomannan for the diagnosis and management of invasive aspergillosis

The availability of the Platelia Aspergillus, a sandwich ELISA kit that detects circulating galactomannan, has been a major advance for managing patients at risk for invasive aspergillosis because of the early detection of the antigen. The assay is now widely used throughout the world, including the USA. Although initial studies that assessed the performance characteristics of this assay reported high sensitivity and specificity, more recent studies show significant variation in performance. The causes of this variability are multifactorial and, in large part, cannot be explained because there is insufficient understanding of the kinetics of galactomannan in vivo. We explored some of the factors that affect the release of the aspergillus antigen that bears the epitope that reacts with the monoclonal antibody used in the ELISA, its leakage from the site of infection into the blood, and its binding to substances present in the blood. Factors that affect the detection of antigen in blood are also discussed, most notably the pretreatment procedure aimed at liberating the antigen from immune complexes. Understanding the biology of galactomannan release by aspergillus will greatly enhance our understanding of the kinetics of this and other surrogate markers and allow their optimum use in the management of invasive aspergillosis.

Screening for circulating galactomannan as a noninvasive diagnostic tool for invasive aspergillosis in prolonged neutropenic patients and stem cell transplantation recipients: a prospective validation

The diagnosis of invasive aspergillosis (IA) in patients with hematologic disorders is not straightforward; lack of sensitive and specific noninvasive diagnostic tests remains a major obstacle for establishing a precise diagnosis. In a series of 362 consecutive high-risk treatment episodes that were stratified according to the probability of IA based on recently accepted case definition sets, the potential for diagnosis of serial screening for circulating galactomannan (GM), a major aspergillar cell wall constituent was validated. After incorporating postmortem findings to allow a more accurate final analysis, this approach proved to have a sensitivity of 89.7% and a specificity of 98.1%. The positive and negative predictive values equaled 87.5% and 98.4%, respectively. False-positive reactions occurred at a rate of 14%, although this figure might be overestimated due to diagnostic uncertainty. More or less stringent criteria of estimation could highly influence sensitivity, which ranged from 100% to 42%; the impact on other test statistics was far less dramatic. All proven cases of IA, including 23 cases confirmed after autopsy only, had been detected before death, although serial sampling appeared to be necessary to maximize detection. The excellent sensitivity and negative predictive value makes this approach suitable for clinical decision making. Unfortunately, given the species-specificity of the assay, some emerging non-Aspergillus mycoses were not detected. In conclusion, serial screening for GM, complemented by appropriate imaging techniques, is a sensitive and noninvasive tool for the early diagnosis of IA in high-risk adult hematology patients.

Use of PCR for diagnosis of invasive aspergillosis: systematic review and meta-analysis

A systematic review and meta-analysis was done on the use of PCR tests for the diagnosis of invasive aspergillosis. Data from more than 10000 blood, serum, or plasma samples obtained from 1618 patients at risk for invasive aspergillosis were retrieved from 16 studies. Overall, the mean diagnostic odds ratios (DORs) of PCR for proven and probable cases were similar whether two consecutive positive samples were required to define positivity (DOR 15.97 [95% CI 6.83-37.34]) or a single positive PCR test was required (DOR 16.41 [95% CI 6.43-41.88]). Sensitivity and specificity of PCR for two consecutive positive samples were 0.75 (95% CI 0.54-0.88) and 0.87 (95% CI 0.78-0.93), respectively, and if only a single positive sample was required, these values were 0.88 (95% CI 0.75-0.94) and 0.75 (95% CI 0.63-0.84), respectively. Whereas specificity based on a single positive test was significantly lower (p=0.027) than two positive tests, the sensitivity and DOR did not differ significantly. A single PCR-negative result is thus sufficient to exclude a diagnosis of proven or probable invasive aspergillosis. However, two positive tests are required to confirm the diagnosis because the specificity is higher than that attained from a single positive test. Populations at risk varied and there was a lack of homogeneity of the PCR methods used. Efforts are underway to devise a standard for Aspergillus sp PCR for screening, which will help enable formal validation of PCR and estimate its use in patients most likely to benefit.

Use of circulating galactomannan screening for early diagnosis of invasive aspergillosis in allogeneic stem cell transplant recipients

Screening for galactomannan (GM) has been adopted by many European centers as part of the management plan for allogeneic stem cell transplant recipients. However, the temporal onset of GM antigenemia remains unknown. A series of allogeneic stem cell transplant recipients were monitored prospectively, and the relationship between antigenemia and other diagnostic triggers for initiation of antifungal therapy was analyzed. GM detection had a sensitivity of 94.4% and a specificity of 98.8%. Positive and negative predictive values were 94.4% and 98.8%, respectively. This statistical profile was better than that of other triggers, including unexplained fever, new pulmonary infiltrates, isolation of Aspergillus species, and abnormalities seen on computed tomography. Antigenemia preceded diagnosis on the basis of radiologic examination or Aspergillus isolation by 8 and 9 days in 80% and 88.8% of patients, respectively. Antigenemia preceded therapy in 83.3% of patients. Detection of GM was especially useful when patients were receiving steroid treatment or when coexisting conditions masked the diagnosis of invasive aspergillosis. Prospective screening for GM allows earlier diagnosis of aspergillosis than do conventional diagnostic criteria.

Use of real-time PCR on blood samples for diagnosis of invasive aspergillosis

We developed a new quantitative system for diagnosis of invasive pulmonary aspergillosis (IPA) using real-time automated polymerase chain reaction (PCR). Intra-assay and interassay precision rates for in vitro examination were 2.53% and 2.20%, respectively, and the linearity of this assay was obtained when there were >20 copies/well. We examined 323 samples taken from 122 patients with hematological malignancies, including 33 patients with IPA and 89 control patients. Blood samples were subjected to PCR antigen detection methods, using enzyme-linked immunosorbent assay (ELISA) and determination of plasma (1-->3)-beta-D-glucan (BDG) concentration. The sensitivities of PCR, ELISA, and BDG measurement for diagnosis of IPA were 79%, 58%, and 67%, respectively; the specificities were 92%, 97%, and 84%. Positive findings on PCR preceded those of computed tomography by -0.3+/-6.6 days, those of BDG measurement by 6.5+/-4.9 days, and those of ELISA by 2.8+/-4.1 days. Real-time PCR was sensitive for IPA diagnosis, and quantitation was accurate.

Pharmacodynamics of caspofungin in a murine model of invasive pulmonary aspergillosis: evidence of concentration-dependent activity

BACKGROUND

A paucity of data exists regarding the pharmacodynamics of caspofungin (CAS) during invasive pulmonary aspergillosis (IPA). We conducted a dosage-fractionation study to characterize the in vivo pharmacodynamics of CAS activity during IPA, using immunosuppressed mice inoculated intranasally with Aspergillus fumigatus.

METHODS

After single intraperitoneal doses (0.25, 1.0, and 4.0 mg/kg), plasma CAS concentrations were assayed by high-performance liquid chromatography. The pharmacokinetic data were analyzed by nonparametric population pharmacokinetic analysis. Three dosage groups (0.25, 1.0, and 4.0 mg/kg) fractionated into 3 different dosing intervals (q6, q24, or q48 h) were then used to evaluate the pharmacokinetic/pharmacodynamic effects (percentage of time greater than the minimum effective concentration [MEC], 96-h area under the plasma concentration curve:MEC ratio, and peak concentration in plasma [Cmax]:MEC ratio) at clinically achievable exposures. Mice were treated for 96 h and were then euthanized, and their lungs were harvested for analysis of pulmonary fungal burden by real-time quantitative polymerase chain reaction.

RESULTS

A concentration-dependent reduction in mean pulmonary fungal burden was evident in mice in the 1 mg/kg dosage-fractionation group, with significantly lower mean pulmonary fungal burden in mice dosed q48 h versus q6 h (P < .01). A paradoxical increase in pulmonary fungal burden was observed in the highest dosage-fractionation group.

CONCLUSIONS

CAS demonstrates concentration-dependent pharmacodynamics in the treatment of IPA. The Cmax : MEC ratio appears to be the parameter most closely associated with the reduction of pulmonary fungal burden.

Optimization of the cutoff value for the Aspergillus double-sandwich enzyme immunoassay

BACKGROUND

Many health care centers worldwide use the Platelia Aspergillus enzyme immunoassay (PA-EIA; Bio-Rad Laboratories) for diagnosis of invasive aspergillosis (IA). A cutoff optical density (OD) index of 1.5 was originally recommended by the manufacturer, but in practice, most institutions use lower cutoff values. Moreover, a cutoff OD index of 0.5 was recently approved in the United States. In the present study, we set out to optimize the cutoff level by performing a retrospective analysis of PA-EIA values for samples that had been obtained prospectively from adult patients at risk for IA at 2 European health care centers.

METHODS

In total, 239 treatment episodes were included of which there were 19 episodes of proven IA and 19 episodes of probable IA. Per-episode and per-test analyses and receiver operating characteristic curves were used to determine the optimal cutoff value.

RESULTS

In the per-episode analysis, lowering the cutoff OD index for positivity from 1.5 to 0.5 increased the overall sensitivity by 21% (from 76.3% to 97.4%) but decreased the overall specificity by 7% (from 97.5% to 90.5%). Requiring 2 consecutive samples with an OD index > or = 0.5 resulted in the highest test accuracy, with an improved positive predictive value. At a cutoff OD index of 0.5, the antigen test result was positive during the week before conventional diagnosis in 65% of cases and during the week of diagnosis in 79.5% of cases.

CONCLUSIONS

A cutoff OD index of 0.5--identical to the approved cutoff in the United States--improves the overall performance of the PA-EIA for adult hematology patients.

Efficacy of unilamellar liposomal amphotericin B in treatment of pulmonary aspergillosis in persistently granulocytopenic rabbits: the potential role of bronchoalveolar D-mannitol and serum galactomannan as markers of infection

A model of primary pulmonary aspergillosis in rabbits was developed to reproduce the persistent levels of profound granulocytopenia and the histopathologic features of bronchopneumonia, vascular invasion, and hemorrhagic infarction encountered in humans. D-mannitol was detectable in bronchoalveolar lavage fluid by gas-liquid chromatography/mass spectroscopy, and galactomannan was measurable in serum by latex agglutination immunoassay. A pharmacokinetically distinctive unilamellar vesicle formulation of liposomal amphotericin B, 5 mg/kg/day intravenously, compared with high-dose conventional desoxycholate amphotericin B, 1 mg/kg/day intravenously, was more effective in preventing nephrotoxicity, increasing survival, reducing the number of viable organisms, and decreasing tissue injury due to Aspergillus organisms. Thus, D-mannitol in lavage fluid and galactomannan in serum may be useful markers of pulmonary aspergillosis, and liposomal amphotericin B was significantly more effective and safer than desoxycholate amphotericin B for treatment of pulmonary aspergillosis in profoundly granulocytopenic rabbits.

Plasma (1-->3)-beta-D-glucan and fungal antigenemia in patients with candidemia, aspergillosis, and cryptococcosis

(1-->3)-beta-D-Glucan is one of the major structural components of fungi, and it seems that it can be detected by the fractionated (1-->3)-beta-D-glucan-sensitive component from a Limulus lysate, factor G. We evaluated the concentration of (1-->3)-beta-D-glucan by using factor G and other fungal antigens in 24 patients with clinical evidence of mycosis and 36 healthy subjects. The mean concentration of (1-->3)-beta-D-glucan in the plasma of the healthy subjects was found to be 2.7 +/- 1.9 pg/ml (range, < 6.9 pg/ml), and it was found to be substantially higher in all 11 patients with candidemia (mean, 2,207.4 pg/ml; range, 325.4 to 8,449.0 pg/ml). Eight of those 11 patients with candidemia (73%) were positive for the Cand-Tec heat-labile candida antigen and only 3 patients (27%) were positive for mannan antigen. Three patients with invasive pulmonary aspergillosis were positive for galactomannan and had, in addition, high concentrations of (1-->3)-beta-D-glucan (mean, 323.3 pg/ml; range, 27.0 to 894.0 pg/ml). All 10 patients with cryptococcosis (including 2 patients with probable cryptococcosis) were positive for cryptococcal antigen by the Eiken latex test; however, (1-->3)-beta-D-glucan levels were not elevated in these patients (mean, 7.0 pg/ml; range, < 16.5 pg/ml). Our results indicated that (1-->3)-beta-D-glucan levels are elevated in patients with candidiasis and aspergillosis but not in those with cryptococcosis.

Immune reconstitution inflammatory syndrome in cancer patients with pulmonary aspergillosis recovering from neutropenia: Proof of principle, description, and clinical and research implications

BACKGROUND

Assessing the outcome of patients with invasive pulmonary aspergillosis by using conventional criteria is difficult, particularly when clinical and radiologic worsening coincides with neutrophil recovery. Usually, it is assumed that this deterioration is related to progressive aspergillosis, prompting changes in patient management. However, its temporal relation with neutrophil recovery suggests that it may be caused by an immune reconstitution syndrome (IRIS). Galactomannan is an Aspergillus-specific polysaccharide that is released during aspergillosis and is detected by the serum galactomannan test, which has been approved by the United States Food and Drug Administration for the diagnosis of invasive aspergillosis. In this study, the authors used sequential galactomannan testing to distinguish IRIS responses from progressive aspergillosis.

METHODS

From April 2001 to December 2006, patients with hematologic malignancies underwent galactomannan screening during periods when they were at risk. The clinical and laboratory findings from patients who had >or=2 consecutive positive galactomannan assays (optical density, >or=0.5) were reviewed.

RESULTS

Nineteen neutropenic patients with aspergillosis developed clinical and radiologic pulmonary deterioration during neutrophil recovery. Deterioration coincided with microbiologic response, as documented by rapid normalization of serum galactomannan, and, in 16 patients, was followed by complete clinical response and survival at 3 months, although there were no changes in antifungal therapy. The 3 patients who died during the first month had no evidence of aspergillosis at autopsy examination.

CONCLUSIONS

The authors propose that IRIS was responsible for the current findings and provide a definition for the syndrome. They also recommend serial galactomannan testing to guide aspergillosis management. Declining galactomannan values imply IRIS with an aspergillus response and obviate the need for invasive procedures and alternative antifungal therapies, whereas persistent galactomannan elevation indicates progressive aspergillosis and requires prompt treatment modification.

Invasive aspergillosis in allogeneic stem cell transplant recipients: increasing antigenemia is associated with progressive disease

The kinetics of serum Aspergillus galactomannan, as determined by enzyme-linked immunosorbent assay, was examined in 37 allogeneic stem cell transplant (SCT) recipients treated for invasive aspergillosis (IA). Fifty-eight periods of response ("response episodes") were evaluated. There were 42 response episodes that were considered "treatment failures" and 16 that were considered "good" (that is, complete or partial) responses. At baseline (the first day of each new response episode), the patients who experienced treatment failure and those who had good responses did not differ significantly with regard to median galactomannan index (GMI) value. Thereafter, GMI values significantly increased in the treatment failure group, whereas no significant changes were observed in the good response group (P=.002). An increase in the GMI value of 1.0 over the baseline value during the first week of observation was predictive of treatment failure with a sensitivity of 44%, a specificity of 87%, and a positive predictive value of 94%. We conclude that serial determination of serum GMI values is a useful tool for assessing prognosis of IA in allogeneic SCT recipients during treatment.

Galactomannan antigenemia and antigenuria in aspergillosis: studies in patients and experimentally infected rabbits

Purified galactomannan (GM) from Aspergillus fumigatus was used in both a radioimmunoassay and an enzyme-linked immunoassay for antigen detection. Results of the two tests seemed interchangeable. By one or both assays, GM was detected in serum from four of 12 rabbits lethally infected with A. fumigatus in concentrations ranging from 108 to 356 ng/ml. Serum antigen was detected in only two of 12 patients with invasive aspergillosis. Results of assay for GM in urine were far more encouraging. Urinary GM was detectable throughout the course of lethal aspergillosis in all 16 rabbits, in concentrations of 24-1,900 ng/ml. Urine from seven of 13 patients with invasive aspergillosis had GM concentrations of 1-83 ng/ml. Antigen excretion roughly paralleled extent of disease.

PCR detection of DNA specific for Aspergillus species in serum of patients with invasive aspergillosis

We investigated the possible presence of DNA specific for Aspergillus species in serum samples of patients with invasive aspergillosis (IA) by the nested PCR method. Fourteen strains of fungi including 5 strains of Aspergillus species and 10 strains of common bacteria were used for examination of specificity and sensitivity of the nested PCR. Two sets of oligonucleotide primers were derived from the sequence of the variable regions V7 to V9 of the 18S rRNA genes of Aspergillus fumigatus. The specific fragment was amplified from five strains of Aspergillus species in the single and nested PCR but not from other microorganisms. Target DNA was detected by the nested PCR with as little as 50 fg of the extracted DNA of A. fumigatus. We investigated the detection of DNA specific for Aspergillus species in serum samples of a murine model of aspergillosis and 20 patients with IA. The specific fragment was detected by the nested PCR in 71% of serum samples of infected mice and 70% of serum samples of patients with IA, while galactomannan antigen was detected in 43 and 60% of samples, respectively. The high sensitivity and specificity of the nested PCR indicate that the assay can provide early diagnosis with sufficient accuracy to be clinically useful for immunocompromised patients with IA.

Long-term itraconazole prophylaxis against Aspergillus infections in thirty-two patients with chronic granulomatous disease

We conducted a prospective, open study of oral itraconazole therapy (5 and then 10 mg/kg per day) to assess tolerance and potential efficacy in preventing fungal infections in patients with chronic granulomatous disease. Thirty-two patients were enrolled in one center between 1985 and 1991. Tolerance was excellent in all cases. Poor compliance was suspected in three cases. Two patients were excluded from efficacy analysis because itraconazole was used as part of therapy for pulmonary aspergillosis. Of 30 patients, 3 developed a fungal (Aspergillus) lung infection, an incidence 3.4/100 patient-years versus 11.5 in a historical control group that did not receive any prophylaxis (p = 0.13) and 9.55 in a historical group of patients who received daily ketoconazole prophylaxis (p = 0.19). The percentage of patients infected with Aspergillus was significantly different: 10% in the itraconazole group versus 34.4% in the untreated group (p = 0.013). These results require further evaluation through a comparative randomized trial to assess the possible benefit of itraconazole prophylaxis in patients with chronic granulomatous disease.

Invasive pulmonary aspergillosis in nonimmunocompromised, nonneutropenic hosts

Invasive pulmonary aspergillosis occurs predominantly in individuals who are neutropenic or who have severe defects in cell-mediated immunity. The isolation of Aspergillus from respiratory secretions of normal hosts usually signifies tracheobronchial colonization, not disease. Recent experience with three nonimmunocompromised patients who had invasive pulmonary aspergillosis, each of whom had Aspergillus isolated from respiratory secretions early in his illness, led to a reassessment of the significance of the isolation of Aspergillus from tracheobronchial secretions. Two of 10 nonimmunocompromised, nonleukopenic individuals who had pulmonary infiltrates and whose sputum yielded Aspergillus had invasive pulmonary aspergillosis, whereas two of five individuals who had pulmonary infiltrates and whose bronchial washings grew Aspergillus had invasive disease. These findings indicate that invasive pulmonary aspergillosis should be considered when Aspergillus is isolated from the respiratory secretions of anyone who has pneumonia, regardless of host defense status.

Muco-cutaneous retinoid-effects and facial erythema related to the novel triazole antifungal agent voriconazole

Voriconazole is a new azole antifungal drug with activity against a wide range of systemic fungal pathogens, including Aspergillus spp. Five patients with chronic invasive aspergillosis were treated for 12-58 weeks with voriconazole, 200 mg twice daily and developed facial erythema and cheilitis. One who received 58 weeks of therapy also developed discoid lupus erythematosus-like lesions on both sides of her neck. Both erythema and cheilitis resolved after discontinuation of voriconazole. Serum retinoids were elevated in the three patients in whom they were measured. Voriconazole has the potential for retinoid-like side-effects and facial erythema.

Defining breakthrough invasive fungal infection-Position paper of the mycoses study group education and research consortium and the European Confederation of Medical Mycology

Breakthrough invasive fungal infections (IFIs) have emerged as a significant problem in patients receiving systemic antifungals; however, consensus criteria for defining breakthrough IFI are missing. This position paper establishes broadly applicable definitions of breakthrough IFI for clinical research. Representatives of the Mycoses Study Group Education and Research Consortium (MSG-ERC) and the European Confederation of Medical Mycology (ECMM) reviewed the relevant English literature for definitions applied and published through 2018. A draft proposal for definitions was developed and circulated to all members of the two organisations for comment and suggestions. The authors addressed comments received and circulated the updated document for approval. Breakthrough IFI was defined as any IFI occurring during exposure to an antifungal drug, including fungi outside the spectrum of activity of an antifungal. The time of breakthrough IFI was defined as the first attributable clinical sign or symptom, mycological finding or radiological feature. The period defining breakthrough IFI depends on pharmacokinetic properties and extends at least until one dosing interval after drug discontinuation. Persistent IFI describes IFI that is unchanged/stable since treatment initiation with ongoing need for antifungal therapy. It is distinct from refractory IFI, defined as progression of disease and therefore similar to non-response to treatment. Relapsed IFI occurs after treatment and is caused by the same pathogen at the same site, although dissemination can occur. These proposed definitions are intended to support the design of future clinical trials and epidemiological research in clinical mycology, with the ultimate goal of increasing the comparability of clinical trial results.

Diagnosing invasive aspergillosis during antifungal therapy by PCR analysis of blood samples

We evaluated the value of Aspergillus PCR as a tool for diagnosing invasive aspergillosis from whole-blood samples during antifungal therapy. In a 3-year study, 36 patients receiving antifungal therapy due to chest radiographic findings highly suggestive of fungal pneumonia were evaluated. The PCR results from whole-blood samples were compared to those obtained from bronchoalveolar lavage fluids and/or tissue specimens. A total of 205 whole-blood samples, 15 fine-needle aspirations or tissue biopsy specimens, and 21 bronchoalveolar lavage fluids and tracheal secretions were analyzed using PCR. Of the 36 patients, 15 had proven, 9 had probable, and 12 had possible invasive Aspergillus infection according to European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions. For patients with proven infection the sensitivity values of PCR in lung and blood samples were 100 and 40%, respectively. The negative predictive value of blood monitoring under conditions of antifungal treatment was 44%. Clearance of fungal DNA from blood was associated with resolution of clinical symptoms in six of nine patients with proven infection. Repeated positive PCR results for Aspergillus were associated with fatal outcome, as three of six patients died. For patients with probable infection the sensitivity values of PCR in lung fluid and blood were 66 and 44%, respectively. The benefit of PCR diagnosis using whole-blood samples is limited when sampling takes place after treatment has been started. Performance of Aspergillus PCR using tissue samples is recommended in addition to microscopic examination and culture technique for sensitive detection of fungal infection.

Serum Aspergillus galactomannan antigen values strongly correlate with outcome of invasive aspergillosis

BACKGROUND

Determining the outcome of patients with aspergillosis can be particularly difficult because patients with aspergillosis are at risk for other conditions that mimic this infection. Galactomannan is an Aspergillus-specific antigen released during invasive aspergillosis and is detected by the quantitative serum galactomannan index (GMI) test.

METHODS

Using a kappa correlation coefficient test (KCC), the strength of correlation was determined between GMI and survival outcome of aspergillosis among 56 adults with hematologic cancer (90% had myeloma) who underwent serial GMI monitoring until hospital discharge or death.

RESULTS

All 56 patients received antineoplastic therapy (myeloablative followed by stem cell transplantation [autologous in 21 patients and allogeneic in 3 patients] or nonmyeloablative therapy [32 patients]). The overall correlation between survival outcome and GMI was excellent (KCC = 0.8609; 95% confidence interval [95% CI], 0.7093-1.000 [P < .0001]) and was comparable among neutropenic and nonneutropenic patients (KCC = 0.8271; 95% CI, 0.6407-1.000 [P < .0001] and KCC = 1.0; 95% CI, 1-1 [P = .0083], respectively).

CONCLUSIONS

The survival outcome of patients with aspergillosis strongly correlated with serum GMI. These findings have important implications for patient care and clinical trials of mold-active antifungal agents.

IL1 gene cluster polymorphisms and its haplotypes may predict the risk to develop invasive pulmonary aspergillosis and modulate C-reactive protein level

OBJECTIVE

The aim of this study was to determine whether interleukin-1 alpha (IL1alpha), interleukin-1 beta (IL1beta), and IL1 receptor antagonist (IL1Ra) polymorphisms are implicated in invasive pulmonary aspergillosis (IPA) pathogenesis.

MATERIALS AND METHODS

Subjects comprised 110 hematological patients and 148 healthy controls. Genotypic and allelic frequencies were similar between hematological patients and controls. IPA was diagnosed in 59 of the 110 patients according to consensus criteria published by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group (EORTC/IFICG).

RESULTS AND DISCUSSIONS

Individual locus analysis showed that IL1alpha and IL1Ra polymorphisms were not associated with the presence of IPA (p = 0.560 and p = 0.680, respectively). However, a trend towards a higher presence of IL1beta( - ) (511TT) genotype (or IL1beta(-511T) allele) in the IPA group than in the non-IPA patient group (p = 0.092 and p = 0.095, respectively) was found. Haplotype analysis revealed that VNTR2/-889C/-511T haplotype was strongly associated with susceptibility to develop IPA infection (p = 0.020). Haplotype analysis also showed an association between VNTR2/-889C/-511C haplotype and resistance to IPA infection (p = 0.028). Furthermore, patients with IL1Ra VNTR2/2 and IL1beta(-511)T/T genotypes had a higher positive serum galactomannan percentage versus patients with other genotypes. Finally, C-reactive protein (CRP) production was significantly associated with IL1 gene cluster polymorphisms, although CRP values were similar between IPA and non-IPA groups.

CONCLUSION

These findings indicate a critical role of IL1 gene cluster polymorphisms in the susceptibility to IPA infection and CRP production.

Comparison between plasma and whole blood specimens for detection of Aspergillus DNA by PCR

Ninety-six plasma and whole blood specimens from nine selected patients were analyzed for the presence of Aspergillus DNA. Nineteen specimens from three patients with proven aspergillosis were PCR positive in both materials, whereas an additional 22 were PCR positive in whole blood only. All 36 samples from six patients without signs of aspergillosis were negative in both assays. We conclude that although plasma and whole blood spiked with Aspergillus conidia showed an identical lower detection limit (10 CFU), the sensitivity of plasma PCR was lower than that of PCR performed on whole blood samples.

Diagnosis of invasive fungal disease using serum (1→3)-β-D-glucan: a bivariate meta-analysis

BACKGROUND

The (1→3)-β-D-Glucan (BG) assay has been approved for diagnosing invasive fungal disease (IFD). However, the test performance has been variable. We conducted a meta-analysis to determine the overall accuracy of BG assay for diagnosing IFD.

METHODS

The sensitivity, specificity, and positive and negative likelihood ratios (PLR and NLR, respectively) of BG for diagnosing IFD were pooled using a bivariate meta-analysis. We also performed subgroup analyses.

RESULTS

Twelve reports, including 15 studies, were included for the analysis (proven and probable IFD vs possible or no IFD). The sensitivity, specificity, PLR and NLR were 0.76 (95% CI, 0.67-0.83), 0.85 (95% CI, 0.73-0.92), 5.05 (95% CI, 2.71-9.43), and 0.28 (95% CI, 0.20-0.39), respectively. Subgroup analyses showed that the BG assay had higher specificities for patients with hematological disorders and a positive BG result with two consecutive samples. The combination of galactomannan and BG increased the specificity value to 0.98 (95% CI, 0.95-0.99) for diagnosing invasive aspergillosis.

CONCLUSION

Serum BG determination is clinically useful for diagnosing IFD in at-risk patients, especially for hematology patients. The combination of galactomannan and BG was sufficient for diagnosing invasive aspergillosis. Since the BG assay is not absolutely sensitive and specific for IFD, the BG results should be interpreted in parallel with clinical findings.

Chemical and immunological analysis of the Aspergillus fumigatus cell wall

Hyphal-wall preparations of Aspergillus fumigatus have been analysed by sequential treatment with KOH, nitrous acid and again with KOH. By acidification of the alkali-soluble extract, a polyglucose was precipitated which showed an X-ray diffraction pattern similar to that of (1-->3)-alpha-glucan. The remainder of the alkali-soluble fraction was precipitated with ethanol; it contained all the mannose, galactose and protein of the wall and, in addition, 6.2% of the amino sugars. This wall-associated glycoprotein, following SDS-PAGE and immunoblotting, reacted with antisera raised against several mycelial extracts of A. fumigatus. Sera from patients with aspergilloma have antibodies which recognize components of this glycoprotein. The glycoprotein nature of these antigens was shown by their ability to bind Lens culinaris lectin. In addition, the antigen/antibody binding could be disrupted by exposure of antigen to periodate oxidation, hydrolysis with dilute acid or pretreatment with a large excess of an exo-beta-D-galactofuranosidase. The alkali-insoluble fraction consisted of a covalently linked glucan-chitin complex. Nitrous acid treatment, which specifically disrupts glycosidic linkages involving glucosamine, did not solubilize much material but changed the X-ray diffraction pattern from diffuse to a pattern showing the characteristic lines of crystalline (1-->3)-beta-glucan and chitin. Most of the glucan became alkali-soluble after this treatment, and the insoluble residue appeared to contain crystalline chitin.