Diagnostic accuracy of Aspergillus-specific antibodies for chronic pulmonary aspergillosis: A systematic review and meta-analysis

Chronic Pulmonary Aspergillosis: Clinical Presentation and Management

Chronic pulmonary aspergillosis (CPA) refers to a number of clinical syndromes resulting from the presence and local proliferation of Aspergillus organisms in the lungs of patients with chronic lung disease. CPA is more common than was realized two decades ago. Recognition remains poor, despite recent studies from many countries highlighting the high prevalence in at-risk populations. In low- and middle-income countries, CPA may be misdiagnosed and treated as tuberculosis (TB). In addition, CPA may develop following successful TB treatment. The coronavirus disease pandemic has resulted in significant disruption to provision of TB care, likely leading to more extensive lung damage, which could increase the risk for CPA.Although CPA refers to various syndromes, the classic presentation is that of chronic cavitary pulmonary aspergillosis, which manifests as one or more progressive cavities with or without a fungal ball, accompanied by systemic and respiratory symptoms for at least 3 months. Diagnosis relies on Aspergillus immunoglobulin G in serum, as sputum culture lacks sensitivity. Differential diagnosis includes mycobacterial infection, bacterial lung abscess or necrotizing pneumonia, lung cancer, and endemic fungi.The aim of antifungal treatment in CPA is to improve symptoms and quality of life, and to halt progression, and possibly reverse radiological changes. Current recommendations suggest treatment for 6 months, although in practice many patients remain on long-term treatment. Improvement may manifest as weight gain and improvement of symptoms such as productive cough, hemoptysis, and fatigue. Surgical management should be considered in cases of diagnostic uncertainty, in significant hemoptysis, and when there is concern for lack of response to therapy. Itraconazole and voriconazole are the first-line azoles, with more experience now accumulating with posaconazole and isavuconazole. Side effects are frequent and careful monitoring including therapeutic drug monitoring is essential. Intravenous antifungals such as echinocandins and amphotericin B are used in cases of azole intolerance or resistance, which often develop on treatment. Relapse is seen after completion of antifungal therapy in around 20% of cases, mostly in bilateral, high-burden disease.Several research priorities have been identified, including characterization of immune defects and genetic variants linked to CPA, pathogenetic mechanisms of Aspergillus adaptation in the lung environment, the contribution of non-fumigatus Aspergillus species, and the role of new antifungal agents, immunotherapy, and combination therapy.

Chronic pulmonary aspergillosis: comprehensive insights into epidemiology, treatment, and unresolved challenges

Chronic pulmonary aspergillosis (CPA) is a challenging respiratory infection caused by the environmental fungus Aspergillus. CPA has a poor prognosis, with reported 1-year mortality rates ranging from 7% to 32% and 5-year mortality rates ranging from 38% to 52%. A comprehensive understanding of the pathogen, pathophysiology, risk factors, diagnosis, surgery, hemoptysis treatment, pharmacological therapy, and prognosis is essential to manage CPA effectively. In particular, Aspergillus drug resistance and cryptic species pose significant challenges. CPA lacks tissue invasion and has specific features such as aspergilloma. The most critical risk factor for the development of CPA is pulmonary cavitation. Diagnostic approaches vary by CPA subtype, with computed tomography (CT) imaging and Aspergillus IgG antibodies being key. Treatment strategies include surgery, hemoptysis management, and antifungal therapy. Surgery is the curative option. However, reported postoperative mortality rates range from 0% to 5% and complications range from 11% to 63%. Simple aspergilloma generally has a low postoperative mortality rate, making surgery the first choice. Hemoptysis, observed in 50% of CPA patients, is a significant symptom and can be life-threatening. Bronchial artery embolization achieves hemostasis in 64% to 100% of cases, but 50% experience recurrent hemoptysis. The efficacy of antifungal therapy for CPA varies, with itraconazole reported to be 43-76%, voriconazole 32-80%, posaconazole 44-61%, isavuconazole 82.7%, echinocandins 42-77%, and liposomal amphotericin B 52-73%. Combinatorial treatments such as bronchoscopic triazole administration, inhalation, or direct injection of amphotericin B at the site of infection also show efficacy. A treatment duration of more than 6 months is recommended, with better efficacy reported for periods of more than 1 year. In anticipation of improvements in CPA management, ongoing advances in basic and clinical research are expected to contribute to the future of CPA management.

Utility of a loop-mediated isothermal amplification detection kit to diagnose chronic pulmonary aspergillosis

BACKGROUND

Diagnosing chronic pulmonary aspergillosis (CPA) is still challenging, and infection with Aspergillus spp. must be detected early. The aim of this study was to evaluate, for the first time, the usefulness of a new loop-mediated isothermal amplification (LAMP) test kit in diagnosing CPA.

METHODS

This cross-sectional study was performed at the National Hospital Organization Kinki-Chuo Chest Medical Center. We prospectively enrolled patients with and without CPA. The primary outcomes of this study were the sensitivity and specificity of LAMP for the diagnosis of CPA.

RESULTS

In total, 34 patients with CPA and 21 without CPA (the control group) were enrolled between October 2019 and December 2021. Among the 34 patients with CPA, cultures were positive for CPA in 16 and negative for 18. The majority of fungi isolated in sputum were A. fumigatus in 15 specimens; Aspergillus flavus was isolated in 1) LAMP demonstrated 55.9% sensitivity (95% confidence interval [CI] 37.9-72.8) and 100.0% specificity (95% CI 77.2-100.0).

CONCLUSION

LAMP is an acceptable tool for diagnosing CPA, and its application in clinical practice necessitates more studies.

The SSS revolution in fungal diagnostics: speed, simplicity and sensitivity

INTRODUCTION

Fungal disease has historically presented a diagnostic challenge due to its often non-specific clinical presentations, relative infrequency and reliance on insensitive and time-intensive fungal culture.

SOURCES OF DATA

We present the recent developments in fungal diagnostics in the fields of serological and molecular diagnosis for the most clinically relevant pathogens; developments that have the potential to revolutionize fungal diagnosis through improvements in speed, simplicity and sensitivity. We have drawn on a body of evidence including recent studies and reviews demonstrating the effectiveness of antigen and antibody detection and polymerase chain reaction (PCR) in patients with and without concurrent human immunodeficiency virus infection.

AREAS OF AGREEMENT

This includes recently developed fungal lateral flow assays, which have a low cost and operator skill requirement that give them great applicability to low-resource settings. Antigen detection for Cryptococcus, Histoplasma and Aspergillus spp. are much more sensitive than culture. PCR for Candida spp., Aspergillus spp., Mucorales and Pneumocystis jirovecii is more sensitive than culture and usually faster.

AREAS OF CONTROVERSY

Effort must be made to utilize recent developments in fungal diagnostics in clinical settings outside of specialist centres and integrate their use into standard medical practice. Given the clinical similarities of the conditions and frequent co-infection, further study is required into the use of serological and molecular fungal tests, particularly in patients being treated for tuberculosis.

GROWING POINTS

Further study is needed to clarify the utility of these tests in low-resource settings confounded by a high prevalence of tuberculosis.

AREAS TIMELY FOR DEVELOPING RESEARCH

The diagnostic utility of these tests may require revision of laboratory work flows, care pathways and clinical and lab coordination, especially for any facility caring for the immunosuppressed, critically ill or those with chronic chest conditions, in whom fungal disease is common and underappreciated.

Sensitivity of Antigen, Serology, and Microbiology Assays for Diagnosis of the Subtypes of Chronic Pulmonary Aspergillosis at a Teaching Hospital in São Paulo, Brazil

Chronic pulmonary aspergillosis (CPA) is divided into five subtypes. The diagnosis of CPA is complicated due to poor sensitivity of the laboratory tests. Diagnostic performance of different antigen, serological, and microbiological methods in subtypes of CPA is unknown. The purpose of this study was to evaluate the diagnostic performance in different subtypes of CPA. A total of 91 participants with CPA were included, and the study was performed at Hospital das Clínicas of University of São Paulo. Bronchoalveolar lavage galactomannan (73%, 11/15), serology by immunodiffusion test (81%, 61/75), and histology (78%, 39/50) had the best sensitivity. The counterimmunoelectrophoresis (CIE) titers had a significant statistical difference between the CPA subtypes (P < 0.001), in which the forms chronic fibrosing pulmonary aspergillosis (CFPA) and subacute invasive aspergillosis (SAIA) had higher titers: 1/64 (interquartile range [IQR]: 1/32-1/256) and 1/64 (1/32-1/128). C-reactive protein generally presented lower values (median 15 mg/L, IQR: 6-33), with higher values in SAIA and lower values for Aspergillus nodule. Overall, we found a low diagnostic sensitivity of current tests. Regarding the CPA subtypes, we did not find great differences in the performance of the tests, but it is observed that the inflammatory markers and CIE titers tend to be higher in forms of the more extensive lung parenchyma involvement, such as SAIA and CFPA.

New estimation of the prevalence of chronic pulmonary aspergillosis (CPA) related to pulmonary TB - a revised burden for India

Background

Chronic pulmonary aspergillosis (CPA) may be confused with, or a coinfection of, pulmonary tuberculosis (PTB), or may manifest itself after completion of antituberculous therapy (ATT).

Methods

Literature searches were conducted on PubMed. The selected studies stated the timing of CPA diagnosis with respect to PTB. The key assumptions for estimating the annual incidence, annual deaths, and 5-year-period prevalence related to CPA were: of the clinically diagnosed PTB patients , 19% of those HIV-negative had CPA and 7% of HIV-positive patients had CPA; the percentage of patients presenting in the first year after PTB diagnosis or developing CPA as ATT finished was 10%; the annual rate of development of CPA from 2-5 years after PTB diagnosis was 1.5%; and the mortality of CPA was 20% in year 1 and 7.5% thereafter to year 5.

Findings

In India, the annual incidence of CPA arising in PTB patients in 2019 was estimated to be 363 601  cases (range 254 521 - 472 682) and 42 766 deaths (range 29  936-55 595) - 10.5% of total PTB deaths. The 5-year-period prevalence of CPA was estimated at   1 575 716 , with an additional 100 715 deaths' total range of deaths 100 436- 186 525) annually.

Interpretation

The revised estimation indicates a substantial unmet need for better diagnosis of CPA as part of a complex PTB-related respiratory morbidity burden.

Chronic Pulmonary Aspergillosis is Common among Patients with Presumed Tuberculosis Relapse in Ghana

Chronic pulmonary aspergillosis (CPA) may mimic pulmonary tuberculosis (PTB). The two diseases are clinically indistinguishable and may result in CPA misdiagnosed as PTB or vice versa. Although PTB is largely recognised as a differential diagnosis of CPA and often ruled out prior to CPA diagnosis, the reverse is uncommon. The aim of this study was to determine the proportion of CPA cases among patients being assessed for PTB. A cross-sectional survey was conducted among consecutive patients referred for GeneXpert Mycobacterium tuberculosis test for the diagnosis of PTB at the Korle-Bu Teaching Hospital, Accra, Ghana. Patients’ demographics, clinical and socioeconomic details were obtained using a structured questionnaire. Blood was collected for Aspergillus and HIV serology, and sputum samples obtained for Aspergillus culture. Chest radiograph was obtained, and computed tomography scan was also done for patients with positive Aspergillus serology or cavitation. CPA was defined using an algorithm developed by the Global Action for Fungal Infections (GAFFI) international expert panel. A total of 154 patients were included in the analysis, of whom 134 (87%) did not have a prior PTB diagnosis. There were 41 (26.6%) GeneXpert positive cases. CPA prevalence was 9.7% overall, but 50% in patients with a prior history of PTB and 3.7% in those without previous PTB. Although CPA is rarely considered as a differential diagnosis of PTB in Ghana, our findings show that CPA may affect half of patients being assessed for PTB relapse. Efforts to diagnose CPA should be prioritised in this patient group.

Establishing Aspergillus-Specific IgG Cut-Off Level for Chronic Pulmonary Aspergillosis Diagnosis: Multicenter Prospective Cohort Study

OBJECTIVES

Aspergillus-specific IgG (Asp-IgG) cut-off level in diagnosing chronic pulmonary aspergillosis (CPA) remains unknown.

METHODS

We prospectively recruited participants with clinical suspicion of CPA in three centers in Taiwan during 2019 June to 2020 August. Serum Aspergillus fumigatus-specific IgG (Asp-IgG) (Phadia, Uppsala, UPPS, Sweden) was examined. Optimal cut-off level was determined by Youden's index and validated.

RESULTS

A total of 373 participants were recruited. In the derivation cohort (n = 262), Asp-IgG had an area under the receiver-operating-characteristic curve (AUC) of 0.832. The optimal cut-off level was 40.5 mgA/L. While applying this cut-off level to the validation cohort (n = 111), the sensitivity and specificity were 86.7% and 80.2%. Lowering the cut-off level from 40.5 to 27 mgA/L, the sensitivity was steady (30/36, 83.3% to 31/36, 86.1%) while specificity dropped from 81.9% (276/337) to 63.5% (214/337). Restricting CPA diagnosis to only chronic cavitary pulmonary aspergillosis (CCPA) and chronic fibrosing pulmonary aspergillosis (CFPA) yielded a cut-off level of 42.3 mgA/L in the derivation cohort with a sensitivity of 100% and specificity of 84.4% in the validation cohort.

CONCLUSIONS

Serum Asp-IgG performs well for CPA diagnosis and provides a low false-positive rate when using a higher cut-off level (preferably around 40 mgA/L).