Diagnosis of Invasive Pulmonary Aspergillosis

The clinical value of Aspergillus-specific IgG antibody test in the diagnosis of nonneutropenic invasive pulmonary aspergillosis

OBJECTIVES

Aspergillus-specific IgG antibody (Asp IgG) has been successfully applied in the diagnosis of chronic pulmonary aspergillosis. We explored its value in nonneutropenic invasive pulmonary aspergillosis (IPA) by a multicenter, prospective, and controlled study.

METHODS

We enrolled 372 clinically suspected nonneutropenic patients with IPA from February 2015 to August 2022. After excluding 4 cases with Aspergillus colonization, the remaining 368 cases were finally confirmed as patients with IPA (n = 99), or non-IPA patients (n = 269) consisting of community-acquired pneumonia (n = 206), tuberculosis (n = 22), nontuberculous mycobacteria (n = 5), lung abscess (n = 6), or noninfectious diseases (n = 30). Asp IgG in plasma samples was tested by enzyme-linked immunosorbent assay.

RESULTS

At cut-off value of ≥80 AU/mL, Asp IgG had much higher sensitivity (59.6% vs. 19.2%, p < 0.0001), but lower specificity (77.0% vs. 96.3%, p < 0.0001) than serum galactomannan (GM) (cut-off value of ≥1.0), and similar sensitivity (59.6% vs. 55.6%, p = 0.611) but lower specificity (77.0% vs. 91.2%, p = 0.001) than bronchoalveolar lavage fluid (BALF) GM (cut-off value of ≥1.0), respectively. Combination diagnosis of either positive for Asp IgG or BALF GM had higher sensitivity (81.0% vs. 55.6%, p = 0.002), but lower specificity (75.2% vs. 91.2%, p = 0.001) than BALF GM alone. The receiver operating characteristic curve showed that Asp IgG had an optimal diagnostic value when the cut-off value was 56.6 AU/ml, and the sensitivity and specificity were 77.8% and 63.9%, respectively.

DISCUSSIONS

The diagnostic value of Asp IgG for IPA is superior to serum GM, and a little inferior to BALF GM in nonneutropenic patients with IPA. Considering the convenience of taking blood samples, it is a good screening and diagnostic method for nonneutropenic patients with IPA, especially for those who cannot bear invasive procedures.

Comparing the diagnostic value of bronchoalveolar lavage fluid galactomannan, serum galactomannanan, and serum 1,3-β-d-glucan in non-neutropenic respiratory disease patients with invasive pulmonary aspergillosis

The incidence of invasive pulmonary aspergillosis (IPA) is increasing higher in non-neutropenic patients. This study aimed to assess the diagnostic performance of bronchoalveolar lavage fluid (BALF). Galactomannan (GM), serum GM, and 1,3-β-d-glucan (BDG) in non-neutropenic respiratory disease patients with IPA.A total of 333 non-neutropenic patients suspected IPA were recruited from Xiamen University Zhong Shan hospital between January 2016 and February 2019. One, 33, and 92 cases were diagnosed with proven, and possible IPA.BALF and serum GM were both elevated in the possible IPA group and the probable/proven IPA group (p < 0.001). BALF and serum GM showed a fair correlation in the possible IPA group (r = 0.286, p = 0.008), and moderate correlation in the probable/proven IPA group (r = 0.466, p = 0.005). When the cutoff value was 0.5, the sensitivity and negative likelihood ratio of BALF GM were superior to serum GM (78.3% vs 47.8%, 96.7% vs 91.6%). The specificity and positive likelihood ratio of BALF GM were slightly weaker than serum GM (91.8% vs 95.4%, 56.7% vs 85.0%). When the cutoff value was 1.0, the sensitivity and negative predictive value of BALF GM were better than serum GM (73.9% vs 26.1%, 94.5% vs 88.8%), and the specificity of were equivalent (99.2%). The optimal cutoff value of BALF GM was 0.6, wherein the sensitivity reached 78.3% and the specificity reached 95.4%. Given the extremely low sensitivity of serum BDG at different cutoff values (≥10 μg/mL = 5.3%, ≥20 μg/mL = 2.1%), it cannot be used as a preferred biomarker.The diagnostic performance of BALF GM was superior to other biomarkers and the optimal cutoff value was 0.6.

Potential value of serum Aspergillus IgG antibody detection in the diagnosis of invasive and chronic pulmonary aspergillosis in non-agranulocytic patients

BACKGROUND

At present, serum Aspergillus IgG and IgM antibody detection is mainly used in the diagnosis of chronic pulmonary aspergillosis (CPA), but its value in the diagnosis of invasive pulmonary aspergillosis (IPA) in non-agranulocytic patients is still unclear. IgM can be used as a marker of acute infection to help diagnose acute infection-related diseases. IgG is a marker of long-term infection and is used to assist in the diagnosis of pre-existing or chronic infection-related diseases. The aim of this study was to investigate and compare the value of serum Aspergillus IgG and IgM antibody detection in the diagnosis of IPA and CPA in non-agranulocytic patients.

METHODS

Fifty-eight cases of pulmonary aspergillosis (37 IPA and 21 CPA cases), 15 cases of community-acquired bacterial pneumonia and 50 cases in the healthy control group were collected. The serum (1,3)-β-D-glucan test (G test) was performed with a chromogenic method, and the galactomannan test (GM test) and Aspergillus IgG and IgM antibody detection were performed by commercial enzyme-linked immunosorbent assay (ELISA) in all patients. The sensitivity and specificity, cut-off value and area under the curve (AUC) of Aspergillus IgG and IgM antibodies were further obtained by receiver operating characteristic (ROC) curves.

RESULTS

The positive rate of the G test, Aspergillus IgG antibody detection and the GM test also showed notable differences among the IPA, CPA, community-acquired bacterial pneumonia and healthy groups (P = 0.006, P <  0.001 and P = 0.217, respectively). Only the positive rate of the GM test showed a significant difference between the IPA and CPA groups (P = 0.04). ROC curves indicated that Aspergillus IgG antibody detection had a higher specificity in the IPA group than in the CPA group (0.952). The detection of Aspergillus IgG antibody can preferably distinguish IPA from community-acquired bacterial pneumonia and healthy controls (sensitivity = 0.923, specificity = 0.459, cut-off value = 134.46, AUC = 0.727). It can also distinguish CPA from community-acquired bacterial pneumonia and healthy controls (sensitivity = 0.952, specificity = 0.692, cut-off value = 75.46, AUC = 0.873).

CONCLUSIONS

Serum Aspergillus IgG antibody detection may have certain clinical value in the diagnosis of IPA and CPA in non-agranulocytic patients.

Special Staining of the Liquid-Based Cytopathology Test in Bronchoalveolar Lavage Fluid for Diagnosis of Invasive Pulmonary Aspergillosis with Nonneutropenic Patients

In recent years, various biomarkers have been gradually applied on bronchoalveolar lavage (BAL) fluid for the diagnosis of invasive pulmonary aspergillosis (IPA). The objective of this study is to assess the value of the liquid-based cytopathology test (LCT) for improving the identification of IPA in BAL fluid from possible IPA patients, following special staining with periodic acid-Schiff staining (PAS) or Grocott's methenamine silver (GMS). A total of 47 consecutive possible IPA patients who underwent bronchoscopy with BAL fluid from January 2017 to December 2018 were included. 45 people had a pair of BAL fluid specimens and 2 patients had two BAL fluid specimens. The 49 pairs of BAL fluid specimens were processed for culture, tuberculosis acid fast staining smear, direct microbial smear, and LCT with special staining (PAS and GMS), respectively. Then, we compared the sensitivity and specificity of PAS and GMS in BAL fluid in high-risk patients. Among 47 possible IPA patients, 25 patients had proven/probable IPA, and 11 patients had other invasive fungal diseases. The sensitivity of GMS was higher than that of PAS (92.11% versus 81.58%; P = 0.175). The specificity of GMS was 81.82%, which was higher than that of PAS (81.82% versus 72.73%; P = 0.611). The negative predictive value (NPV) for PAS and GMS were 53.33% and 75.00%, respectively. The positive predictive value (PPV) for PAS and GMS were 91.18% and 94.59%, respectively. This study showed that special staining of LCT in BAL fluid may be a novel method for the diagnosis of IPA, and the GMS of LCT had higher sensitivity and specificity, which was superior to PAS.

Clinical features of fatal severe fever with thrombocytopenia syndrome that is complicated by invasive pulmonary aspergillosis

INTRODUCTION

Severe fever with thrombocytopenia syndrome (SFTS) has been prevalent in parts of Asia during recent years. However, SFTS with invasive pulmonary aspergillosis (IPA) is rare, and it is important to understand its clinical features.

MATERIALS AND METHODS

Total four cases of SFTS with IPA are reviewed and detailing the disease progression, treatment options, and prognosis were summarized and analyzed.

RESULTS

The patients with SFTS-associated IPA first presented with fever, gastrointestinal symptoms, thrombocytopenia, leukopenia, and multiple organ failure. After 1-2 weeks, the patients developed mild polypnea and wheezing rales, and quickly developed dyspnea and respiratory failure. Tracheal intubation was usually performed, but did not relieve the intractable airway spasm and pulmonary ventilation failure. Bronchoscopy confirmed that the antifungal treatment was ineffective and the aspergillosis had worsened. All patients died of type 2 respiratory failure caused by continued airway obstruction and spasticity.

CONCLUSIONS

Given the high mortality rate in this series, there is a need for increased awareness of SFTS-associated IPA. Additional examinations should be performed in these cases, and early-stage antifungal treatment with organ support may be helpful.

Nucleic acid amplification methodologies for the detection of pulmonary mold infections

INTRODUCTION

The detection of pulmonary mold infections has historically required technically demanding methods obtained through invasive procedures. Nucleic acid amplification assays have the potential to circumvent the technical hurdles associated with diagnosis, but are not without potential pitfalls. Areas covered: In this paper, the authors review new assays for the diagnosis of pulmonary mold infections due to aspergillosis, mucormycosis, and hyalohyphomycoses as well as uncommon infections caused by dematiaceous molds. Expert commentary: Nucleic acid amplification assays have the potential to rapidly identify patients with invasive mycoses and could shorten the time to implementation of appropriate antimicrobial therapy. However, selection of appropriate patient populations will be crucial to ensure the highest Bayesian positive predictive value for any novel diagnostic platform.

Translational Development and Application of (1→3)-β-d-Glucan for Diagnosis and Therapeutic Monitoring of Invasive Mycoses

Early diagnosis and prompt initiation of appropriate antimicrobial therapy are crucial steps in the management of patients with invasive fungal infections. However, the diagnosis of invasive mycoses remains a major challenge in clinical practice, because presenting symptoms may be subtle and non-invasive diagnostic assays often lack sensitivity and specificity. Diagnosis is often expressed on a scale of probability (proven, probable and possible) based on a constellation of imaging findings, microbiological tools and histopathology, as there is no stand-alone assay for diagnosis. Recent data suggest that the carbohydrate biomarker (1→3)-β-d-glucan may be useful in both the diagnosis and therapeutic monitoring of invasive fungal infections due to some yeasts, molds, and dimorphic fungi. In this paper, we review recent advances in the use of (1→3)-β-d-glucan to monitor clinical response to antifungal therapy and explore how this assay may be used in the future.

Diagnosis, classification, and therapeutic interventions for sinopulmonary Aspergillosis

INTRODUCTION

Sinopulmonary aspergillosis represents a diverse collection of allergic, invasive, and chronic sinus and respiratory conditions. These diseases can affect patients with and without immune impairment and in some cases may be life-threatening. Areas covered: We review the diagnosis, classification, and therapeutic options available to treat sinopulmonary aspergillosis and look ahead to emerging diagnostic and therapeutic options that may soon play an important role in clinical practice. Expert commentary: Histopathology and tissue culture remain the gold standard for the diagnosis of invasive sinopulmonary aspergillosis, but several new molecular detection methods have recently emerged, including various PCR-based platforms, MALDI-TOF, and lateral flow assays. We examine these methodologies as well as the barriers associated with the standardization, validation, and implementation. We also explore the pipeline of antifungal agents in development to treat sinopulmonary aspergillosis.