Non-fumigatus Aspergillus infection associated with a negative Aspergillus precipitin test in patients with chronic pulmonary aspergillosis

Chronic Pulmonary Aspergillosis Caused by Aspergillus tubingensis Diagnosed by a Bronchoscopic Biopsy

We herein report a case of chronic pulmonary aspergillosis (CPA) caused by Aspergillus tubingensis diagnosed by a bronchoscopic biopsy with negative serological and sputum culture findings. A 66-year-old man was referred for the assessment of a pulmonary cavity. Computed tomography showed a thick-walled cavity in the upper right pulmonary lobe. Serum β-D glucan, Aspergillus galactomannan, and Aspergillus antibody tests were negative. Aspergillus species were not detected in the sputum. Culture and pathological specimens were obtained from the mass by bronchoscopy. Microscopic examination findings were consistent with Aspergillus niger complex morphologically and identified as Aspergillus tubingensis through DNA sequencing. The patient was diagnosed with chronic pulmonary aspergillosis.

Diagnostic Laboratory Features and Performance of an Aspergillus IgG Lateral Flow Assay in a Chronic Pulmonary Aspergillosis Cohort

Chronic pulmonary aspergillosis (CPA) is a chronic and progressive fungal disease with high morbidity and mortality. Avoiding diagnostic delay and misdiagnosis are concerns for CPA patients. However, diagnostic practice is poorly evaluated, especially in resource-constrained areas where Aspergillus antibody testing tools are lacking. This study aimed to investigate the diagnostic laboratory findings in a retrospective CPA cohort and to evaluate the performance of a novel Aspergillus IgG lateral flow assay (LFA; Era Biology, Tianjin, China). During January 2016 and December 2021, suspected CPA patients were screened at the Center for Infectious Diseases at Huashan Hospital. A total of 126 CPA patients were enrolled. Aspergillus IgG was positive in 72.1% with chronic cavitary pulmonary aspergillosis, 75.0% with chronic necrotizing pulmonary aspergillosis, 41.7% with simple aspergilloma, and 30.3% with Aspergillus nodule(s). The cavitary CPA subtypes had significantly higher levels of Aspergillus IgG. Aspergillus IgG was negative in 52 patients, who were finally diagnosed by histopathology, respiratory culture, and metagenomic next-generation sequencing (mNGS). Sputum culture was positive in 39.3% (42/107) of patients and Aspergillus fumigatus was the most common species (69.0%, 29/42). For CPA cohort versus controls, the sensitivity and specificity of the LFA were 55.6% and 92.7%, respectively. In a subgroup analysis, the LFA was highly sensitive for A. fumigatus-associated chronic cavitary pulmonary aspergillosis (CCPA; 96.2%, 26/27). Given the complexity of the disease, a combination of serological and non-serological tests should be considered to avoid misdiagnosis of CPA. The novel LFA has a satisfactory performance and allows earlier screening and diagnosis of CPA patients. IMPORTANCE There are concerns on avoiding diagnostic delay and misdiagnosis for chronic pulmonary aspergillosis due to its high morbidity and mortality. A proportion of CPA patients test negative for Aspergillus IgG. An optimal diagnostic strategy for CPA requires in-depth investigation based on real-world diagnostic practice, which has been rarely discussed. We summarized the clinical and diagnostic laboratory findings of 126 CPA patients with various CPA subtypes. Aspergillus IgG was the most sensitive test for diagnosing CPA. However, it was negative in 52 patients, who were finally diagnosed by non-serological tests, including biopsy, respiratory culture, and metagenomic next-generation sequencing. We also evaluated a novel Aspergillus IgG lateral flow assay, which showed a satisfactory performance in cavitary CPA patients and was highly specific to Aspergillus fumigatus. This study gives a full picture of the diagnostic practice for CPA patients in Chinese context and calls for early diagnosis of CPA with combined approaches.

Validity of Platelia Aspergillus IgG and Aspergillus Precipitin Test To Distinguish Pulmonary Aspergillosis from Colonization

When Aspergillus, an ubiquitous, saprophytic fungus, is detected in respiratory tract specimens collected from chronic respiratory disease patients, it is important to determine whether it is a true infection or colonization. We investigated the usefulness of the Bio-Rad Platelia Aspergillus IgG (Platelia Aspergillus IgG) enzyme-linked immunosorbent assay (ELISA) method and the Aspergillus precipitin test to distinguish pulmonary aspergillosis from colonization. Between January 2017 and November 2021, 51 confirmed, untreated pulmonary aspergillosis (33 chronic pulmonary aspergillosis [CPA] and 18 allergic bronchopulmonary aspergillosis [ABPA]) and 77 colonization patients were included in this study. At first, the conventional cutoff value was utilized in assessing the validity of the two antibody tests for distinguishing pulmonary aspergillosis from colonization. The Platelia Aspergillus IgG cutoff value was then reevaluated to fit this situation. Finally, differences in test accuracy dependent on Aspergillus species were assessed for both antibody tests by comparing cases with Aspergillus fumigatus complex and those with non-fumigatus Aspergillus complex. Both antibody tests demonstrated significantly higher positive rates for pulmonary aspergillosis (P < 0.0001) than colonization. The cutoff value should be 15.7 arbitrary units (AU)/mL to best distinguish infection from colonization, which was higher than the conventional value of 10 AU/mL. The diagnostic sensitivity of Platelia Aspergillus IgG for the non-fumigatus Aspergillus complex was inferior to the A. fumigatus complex (P = 0.019). In conclusion, both Aspergillus antibody tests were valid to distinguish infection from colonization, although we should note the higher cutoff value for Platelia Aspergillus IgG and the lower sensitivity in cases of non-fumigatus Aspergillus infection. IMPORTANCE Pulmonary aspergillosis is the most common pulmonary fungal infection. However, Aspergillus is a ubiquitous, saprophytic fungus; it can be detected in respiratory specimens even in the absence of infection. Especially since Aspergillus is detected in respiratory specimens collected from patients with chronic respiratory disease, it is important to determine whether it is true infection or colonization. We investigated the validity of the Platelia Aspergillus IgG ELISA method and the Aspergillus precipitin test to distinguish pulmonary aspergillosis from colonization. Both antibody tests were considered useful in differentiating true infection from colonization in respiratory practice. The appropriate cutoff value for Platelia Aspergillus IgG was higher than the conventional value, and it was also noted that the sensitivity of both antibody tests for non-fumigatus Aspergillus complex was low. This study will be significant in real-world clinical practice of pulmonary aspergillosis using antibody tests in respiratory care.

EQUAL CPA Score 2022: a tool to measure guideline adherence for chronic pulmonary aspergillosis

BACKGROUND

Chronic pulmonary aspergillosis (CPA) can complicate underlying pulmonary diseases, and clinical management of CPA is challenging. Guidelines support clinicians but due to the complexity of the disease they can be difficult to adhere to.

OBJECTIVES

To map current guideline recommendations for the clinical management of CPA into a scoring tool to facilitate and quantify guideline adherence in clinical practice.

METHODS

Recommendations for diagnosis, treatment and follow-up of CPA presented in the current ESCMID/ERS/ECMM and CPAnet guidance documents were assembled and weighed on the basis of their strength of recommendation and level of evidence.

RESULTS

Twenty-seven recommendations were identified, resulting in a total maximum EQUAL CPA Score of 51. For diagnostics (ScoreMax = 27), a strong emphasis on expert consultation, culture, direct microscopy, histopathology, serology and imaging was reflected in respective points, whereas molecular techniques and susceptibility testing count into the diagnostics score to a lesser extent.Ten treatment recommendations (ScoreMax = 14), including antifungal therapy, therapeutic drug monitoring and treatment duration, were identified. Surgery, where indicated, adds three points. For refractory disease or intolerance of first-line antifungal treatment, optimal second-line treatment added another two points.During follow-up (ScoreMax = 10), response assessment via imaging gave three points, while culture and serology added two points each to the ScoreMax.

CONCLUSION

The EQUAL CPA Score intents to be used as a comprehensive tool for measuring guideline adherence. If adherence to current guidelines is associated with clinical outcome, this will be assessed in future studies.