The development of pulmonary aspergillosis and its histologic, clinical, and radiologic manifestations

Characterization of Aspergillus fumigatus secretome during sublethal infection of Galleria mellonella larvae

Introduction. The fungal pathogen Aspergillus fumigatus can induce prolonged colonization of the lungs of susceptible patients, resulting in conditions such as allergic bronchopulmonary aspergillosis and chronic pulmonary aspergillosis.Hypothesis. Analysis of the A. fumigatus secretome released during sub-lethal infection of G. mellonella larvae may give an insight into products released during prolonged human colonisation.Methodology. Galleria mellonella larvae were infected with A. fumigatus, and the metabolism of host carbohydrate and proteins and production of fungal virulence factors were analysed. Label-free qualitative proteomic analysis was performed to identify fungal proteins in larvae at 96 hours post-infection and also to identify changes in the Galleria proteome as a result of infection.Results. Infected larvae demonstrated increasing concentrations of gliotoxin and siderophore and displayed reduced amounts of haemolymph carbohydrate and protein. Fungal proteins (399) were detected by qualitative proteomic analysis in cell-free haemolymph at 96 hours and could be categorized into seven groups, including virulence (n = 25), stress response (n = 34), DNA repair and replication (n = 39), translation (n = 22), metabolism (n = 42), released intracellular (n = 28) and cellular development and cell cycle (n = 53). Analysis of the Gallerial proteome at 96 hours post-infection revealed changes in the abundance of proteins associated with immune function, metabolism, cellular structure, insect development, transcription/translation and detoxification.Conclusion. Characterizing the impact of the fungal secretome on the host may provide an insight into how A. fumigatus damages tissue and suppresses the immune response during long-term pulmonary colonization.

The Role of Ultrasound in the Diagnosis of Pulmonary Infection Caused by Intracellular, Fungal Pathogens and Mycobacteria: A Systematic Review

BACKGROUND

Lung ultrasound (LUS) is a widely available technique allowing rapid bedside detection of different respiratory disorders. Its reliability in the diagnosis of community-acquired lung infection has been confirmed. However, its usefulness in identifying infections caused by specific and less common pathogens (e.g., in immunocompromised patients) is still uncertain.

METHODS

This systematic review aimed to explore the most common LUS patterns in infections caused by intracellular, fungal pathogens or mycobacteria.

RESULTS

We included 17 studies, reporting a total of 274 patients with M. pneumoniae, 30 with fungal infection and 213 with pulmonary tuberculosis (TB). Most of the studies on M. pneumoniae in children found a specific LUS pattern, mainly consolidated areas associated with diffuse B lines. The typical LUS pattern in TB consisted of consolidation and small subpleural nodes. Only one study on fungal disease reported LUS specific patterns (e.g., indicating "halo sign" or "reverse halo sign").

CONCLUSIONS

Considering the preliminary data, LUS appears to be a promising point-of-care tool, showing patterns of atypical pneumonia and TB which seem different from patterns characterizing common bacterial infection. The role of LUS in the diagnosis of fungal disease is still at an early stage of exploration. Large trials to investigate sonography in these lung infections are granted.

Imaging Approach to Pulmonary Infections in the Immunocompromised Patient

Pulmonary infections are the major cause of morbidity and mortality in immunocompromised patients and almost one-third of intensive care unit patients with pulmonary infections belong to the immunocompromised category. Multiple organisms may simultaneously infect an immunocompromised patient and the overwhelming burden of mixed infections further predisposes critically ill patients to acute hypoxemic respiratory failure. Notwithstanding that lung ultrasound is coming into vogue, the primary imaging investigation is a chest radiograph, followed by thoracic CT scan. This review based on our experience at tertiary care teaching hospitals provides insights into the spectrum of imaging features of various pulmonary infections occurring in immunocompromised patients. This review is unique as, firstly, the imaging spectrum described by us is categorized on basis of the etiological infective agent, comprehensively and emphatically correlated with the clinical setting of the patient. Secondly, a characteristic imaging pattern is emphasized in the clinical setting-imaging-pattern conglomerate, to highlight the most likely diagnosis possible in such a combination. Thirdly, the simulating conditions for a relevant differential diagnosis are discussed in each section. Fourthly, not only are the specific diagnostic and tissue sampling techniques for confirmation of the suspected etiological agent described, but the recommended pharmaco-therapeutic agents are also enumerated, so as to provide a more robust insight to the radiologist. Last but not the least, we summarize and conclude with a diagnostic algorithm, derived by us from the characteristic illustrative cases. The proposed algorithm, illustrated as a flowchart, emphasizes a diagnostic imaging approach comprising: correlation of the imaging pattern with clinical setting and with associated abnormalities in the thorax and in other organs/systems, which is comprehensively analyzed in arriving at the most likely diagnosis. Since a rapid evaluation and emergent management of such patients is of pressing concern not only to the radiologist, but also for the general physicians, pulmonologists, critical care specialists, oncologists and transplant surgery teams, we believe our review is very informative to a wide spectrum reader audience.

Co-existing active pulmonary tuberculosis with aspergilloma in a diabetic patient: A rare case report

Pulmonary aspergilloma is commonly associated with tuberculosis. Pulmonary aspergilloma is found in residual tuberculosis cavities and potential for other pathogens’ infections due to its sufficient oxygen and necrotizing tissue. A 48-year-old woman came with shortness of breath and cough for 7 months. She was diagnosed with pulmonary tuberculosis 9 months ago and was still under anti-tuberculosis drug therapy. She also suffered from type II diabetes mellitus. Chest examination showed vesicular sound decreased in third to fourth left intercostal spaces. A chest x-ray revealed a thick-walled cavity with the air-crescent sign in the left upper lobe lung leads to aspergilloma and active pulmonary tuberculosis. This finding was confirmed by the contrast-enhanced CT scan of the chest and continued to lobectomy. Histological examination confirmed the presence of a granuloma formation, necrosis, hyphae structure with the conclusion of Aspergillus sp. infection.

Imaging of pulmonary infections after lung transplantation: a pictorial essay of early and late computed tomography findings

Pulmonary infections are among the most common complications after lung transplants and a major cause of morbidity and mortality in these patients. Computed tomography is one of the main non-invasive diagnostic tools for detecting lung infections but characterizing the correct etiology may be very challenging. Indeed, although several pathogens show typical patterns at imaging, others, such as bacteria, may demonstrate quite unspecific features. Therefore, additional parameters, like the timing of the infection, should be evaluated to support the radiologists in narrowing the differential diagnoses. In fact, it has been demonstrated that several pathogens, like Candida albicans, usually occurring within the first month after the transplant, frequently occur at specific time points. Thus, aim of this review is to make radiologists and clinicians familiar with the computed tomography patterns of pulmonary infections occurring after lung transplant, considering the etiology and the time of onset, according to the extensive experience gained in our tertiary center.

Systemic Aspergillosis: Radiological Findings in a Case With Diffuse Large B Cell Lymphoma Treated by Ibrutinib

Herein, we present a case of systemic aspergillosis with a fatal outcome in a case with diffuse large B cell lymphoma (DLBCL) treated by ibrutinib. Aspergillosis was suspected clinically and proven microbiologically. Radiological findings were compatible with aspergillosis. We aim to review radiological findings in a case with DLBCL treated with ibrutinib, which is an important tyrosine kinase inhibitor used in lymphoid neoplasias.

Characteristics of the Computed Tomography Imaging Findings in 72 Patients with Airway-Invasive Pulmonary Aspergillosis

BACKGROUND This multiple-center retrospective study aimed to investigate computed tomography (CT) imaging findings in 72 patients with airway-invasive pulmonary aspergillosis. MATERIAL AND METHODS Seventy-two patients with airway-invasive pulmonary aspergillosis confirmed by pathology results were divided into 3 types according to image characteristics. Type I involved the trachea or the main bronchus. Type II involved the lobular and segmental bronchi, which manifested early as bronchial wall thickening, and later development was divided into types IIa and IIb. Type IIa manifested as bronchiectasis, and type IIb manifested as consolidation around the bronchus. Type III involved the bronchioles and pulmonary parenchyma, with tree-in-bud sign and acinar nodules around. CT signs of the various types and their differentiation were investigated. RESULTS The main clinical manifestations of the 72 patients with airway-invasive pulmonary aspergillosis were shortness of breath (55/72, 76.4%), cough (40/72, 55.6%), expectoration (35/72, 48.6%), dyspnea (8/72, 11.1%), weight loss (2/72, 2.8%), and fever (30/72, 41.7%). CT typing identified 3 types: 2 patients (2.8%) had type I, presenting as thickening of trachea or main bronchial walls; 3 patients (4.2%) had early type II, manifesting as thickening of lobular or segmental bronchial walls; 27 patients (37.5%) developed type IIa, manifesting as bronchiectasis; 22 patients (30.6%) had type IIb, manifesting as consolidation around the bronchus; and 18 patients (25.0%) had type III, presenting as nodules and patchy shadows with small cavities in the periphery of the lung. CONCLUSIONS Airway pulmonary aspergillosis has characteristic imaging findings, which can help early clinical diagnosis through classification according to CT imaging characteristics.

[Individualized antifungal therapy in critically ill patients with invasive fungal infection]

Invasive candidiasis (IC) is the most common invasive fungal infection (IFI) affecting critically ill patients, followed by invasive pulmonary aspergillosis (IPA). International guidelines provide different recommendations for a first-line antifungal therapy and, in most of them, echinocandins are considered the first-line treatment for IC, and triazoles are so for the treatment of IPA. However, liposomal amphotericinB (L-AmB) is still considered a second-line therapy for both clinical entities. Although in the last decade the management of IFI has improved, several controversies persist. The antifungal drugs currently available may have a suboptimal activity, or be wrongly used in certain IFI involving critically ill patients. The aim of this review is to analyze when to provide individualized antifungal therapy to critically ill patients suffering from IFI, emphasizing the role of L-AmB. Drug-drug interactions, the clinical status, infectious foci (peritoneal candidiasis is discussed), the fungal species involved, and the need of monitoring the concentration of the antifungal drug in the patient are considered.

Differential diagnoses of COVID-19 pneumonia: the current challenge for the radiologist-a pictorial essay

BACKGROUND

COVID-19 pneumonia represents the most severe pandemic of the twenty-first century and has crucial clinical, social and economical implications. The scientific community has focused attention and resources on clinical and radiological features of COVID-19 pneumonia. Few papers analysing the vast spectrum of differential diagnoses have been published.

MAIN BODY

Complexity of differential diagnosis lays in the evidence of similar radiological findings as ground-glass opacities, crazy paving pattern and consolidations in COVID-19 pneumonia and a multitude of other lung diseases. Differential diagnosis is and will be extremely important during and after the pandemic peak, when there are fewer COVID-19 pneumonia cases. The aim of our pictorial essay is to schematically present COVID-19 pneumonia most frequent differential diagnoses to help the radiologist face the current COVID-19 pneumonia challenge.

CONCLUSIONS

Clinical data, laboratory tests and imaging are pillars of a trident, which allows to reach a correct diagnosis in order to grant an excellent allocation of human and economical resources. The radiologist has a pivotal role in the early diagnosis of COVID-19 pneumonia because he may raise suspicion of the pathology and help to avoid COVID-19 virus spread.

Pulmonary Aspergillosis: What the Generalist Needs to Know

Aspergillus spp. is a ubiquitous mold found commonly in our environment that can cause a spectrum of pulmonary disorders, ranging from a hypersensitivity reaction to an acutely invasive disease with significant mortality. Allergic bronchopulmonary aspergillosis results from airway hypersensitivity from aspergillus colonization almost exclusively in patients with asthma and cystic fibrosis. Chronic pulmonary aspergillosis typically presents in immunocompetent patients with underlying lung pathology. Treatment is primarily with antifungal agents; however, other measures such as surgical resection may be necessary. Invasive pulmonary aspergillosis is a severe infection in immunocompromised patients and is characterized by invasion of pulmonary vasculature by the Aspergillus hyphae. Recent advances in the diagnosis and management of invasive pulmonary aspergillosis include emerging risk factors such as critically ill patients, and those with chronic obstructive pulmonary disease and liver disease. In addition, noninvasive biomarkers have made it easier to suspect and diagnose invasive pulmonary aspergillosis. There are more effective and better-tolerated antifungal agents that have improved patient outcomes. This review introduces the spectrum of pulmonary aspergillosis geared toward generalists, including disease manifestations, most recent diagnostic criteria, and first-line treatment options. Involving a multidisciplinary team is vital to the early diagnosis and management of these diseases.

Infective patterns of cryptococcosis in patients with connective tissue disease: a retrospective study

OBJECTIVES

To explore the clinical features and associated factors of cryptococcosis in patients with connective tissue disease (CTD) from Southern China.

METHODS

Demographic and clinical data were collected between 2007 and 2018. Associated factors were analyzed by logistic regression analysis.

RESULTS

A total of 6809 inpatients with CTD were included. Cryptococcosis was diagnosed in 30 patients (prevalence, 0.4%). Cryptococcosis was predominant in patients with ANCA-associated vasculitis (AAV) (prevalence, 6/530, 1.1%). Lung was commonly involved (18/30, 60.0%), followed by meninges (6/30, 20.0%), blood stream (5/30, 16.7%), and disseminated cryptococcosis (involved blood stream and meninges) (1/30, 3.3%). Infiltrates (10/18, 55.6%) and small nodules (8/18, 44.4%) were the main radiographic manifestation of pulmonary cryptococcosis (PC). The positive rate of serum cryptococcal antigen (CrAg) in patients with PC was 88.2%. Cryptococcus spp. were found in 75% (3/4) patients who underwent lung biopsy. Most of the patients with cryptococcal meningitis (CM) had elevated cerebrospinal fluid (CSF) opening pressure (6/7, 85.7%) and decreased CSF glucose level (5/7, 71.4%). Positive blood culture confirmed the diagnosis of cryptococcal sepsis (CS). Three patients died (10.0%), including one with CM and two with PC. Multivariate logistic regression analysis showed that accumulated dose of glucocorticoid (GC) [odds ratio (OR) = 1.42, 95% confidence interval (CI) 1.04-1.93, P = 0.03] was associated with cryptococcosis in patients with CTD.

CONCLUSIONS

Cryptococcosis develops in various organs. Typical radiological manifestation accompanied with positive serum CrAg provides helpful clues for the diagnosis. Lumbar puncture is a critical diagnostic method to distinguish CM. The accumulated dose of GC is associated with cryptococcosis in patients with CTD. Key Points • Pulmonary cryptococcosis is suspected if pulmonary nodules adjacent to the pleura are present, with serum CrAg positive. • Cryptococcal meningitis has insidious onset and the diagnosis mainly depends on lumber puncture. • Cryptococcal sepsis is not rare and needs timely blood culture in suspected patients.

Overexpression of Dendritic Cell-Specific Intercellular Adhesion Molecule-3-Grabbing Nonintegrin in Dendritic Cells Protecting against Aspergillosis

Background:

Dendritic cells (DCs) play an important role in host defense against pathogen infection. DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (SIGN) is a group II C-type lectin receptor and specifically expressed on the surface of DCs. This study aimed to determine whether DC-SIGN affects intracellular signaling activation, Th1/Th2 imbalance and aspergillus immune evasion in aspergillus infection, and explore the application of DC-SIGN-modified DCs in immunotherapy.

Methods:

DCs were first obtained from the mononuclear cells of peripheral blood. The interferon (IFN)-γ and dexamethasone (Dex) were used to stimulate DCs. The expression of DC-SIGN, Th1 and Th2 cytokines, and the capacity of DCs in stimulating T cells proliferation and phagocytosis, and nuclear factor (NF)-κB activation were analyzed. In addition, adenovirus expression vector Ad-DC-SIGN was generated to transfect DCs. Mannan was used to block DC-SIGN signaling for confirming the involvement of DC-SIGN function in Aspergillus fumigatus (Af)-induced DCs maturation. The unpaired, two-tailed Student's t-test was used in the comparisons between two groups.

Results:

Exogenous IFN-γ could activate Af-induced DCs and promote the Th0 cells toward Th1 profile (interleukin [IL]-12 in IFN-γ/Af group: 50.96 ± 4.38 pg/ml; control/Af group: 29.70 ± 2.00 pg/ml, t = 10.815, P < 0.001). On the other hand, Dex inhibited the secretion of Th2 cytokines (IL-10 in Dex/Af group: 5.27 ± 0.85 pg/ml; control/Af group: 15.14 ± 1.40 pg/ml, t = 14.761, P < 0.001)), and successfully caused immunosuppression. After transfection with Ad-DC-SIGN, DCs have improved phagocytosis (phagocytosis rates in Ad-DC-SIGN group: 74.0% ± 3.4%; control group: 64.7% ± 6.8%, t = 3.104, P = 0.013). There was more Th1 cytokine secreted in the Af-induced DC-SIGN modified DCs (IL-12 in Ad-DC-SIGN/Af group: 471.98 ± 166.31 pg/ml; control/Af group: 33.35 ± 5.98 pg/ml, t = 6.456, P = 0.001), correlated to the enhanced NF-κB activation.

Conclusion:

Overexpressing DC-SIGN in DCs had a protective function on aspergillosis.