Lung and sinus fungal infection imaging in immunocompromised patients

BACKGROUND

Imaging is a key diagnostic modality for suspected invasive pulmonary or sinus fungal disease and may help to direct testing and treatment. Fungal diagnostic guidelines have been developed and emphasize the role of imaging in this setting. We review and summarize evidence regarding imaging for fungal pulmonary and sinus disease (in particular invasive aspergillosis, mucormycosis and pneumocystosis) in immunocompromised patients.

OBJECTIVES

We reviewed data on imaging modalities and findings used for diagnosis of invasive fungal pulmonary and sinus disease.

SOURCES

References for this review were identified by searches of PubMed, Google Scholar, Embase and Web of Science through 1 April 1 2023.

CONTENT

Computed tomography imaging is the method of choice for the evaluation of suspected lung or sinus fungal disease. Although no computed tomography radiologic pattern is pathognomonic of pulmonary invasive fungal disease (IFD) the halo sign firstly suggests an angio-invasive pulmonary aspergillosis while the Reversed Halo Sign is more suggestive of pulmonary mucormycosis in an appropriate clinical setting. The air crescent sign is uncommon, occurring in the later stages of invasive aspergillosis in neutropenic patients. In contrast, new cavitary lesions should suggest IFD in moderately immunocompromised patients. Regarding sinus site, bony erosion, peri-antral fat or septal ulceration are reasonably predictive of IFD.

IMPLICATIONS

Imaging assessment of the lung and sinuses is an important component of the diagnostic work-up and management of IFD in immunocompromised patients. However, radiological features signs have sensitivity and specificity that often vary according to underlying disease states. Periodic review of imaging studies and diagnostic guidelines characterizing imaging findings may help clinicians to consider fungal infections in clinical care thereby leading to an earlier confirmation and treatment of IFD.

Invasive pulmonary and central nervous system aspergillosis in a child: A case report and literature review

RATIONALE

Children with haematological malignancies have a higher risk of developing aggressive pulmonary aspergillosis and a higher mortality rate. The most common site of extrapulmonary aspergillosis in children is the central nervous system (CNS), and the death rate is higher when CNS is affected. Therefore, early diagnosis and treatment of invasive aspergillosis are essential for reducing mortality.

PATIENT CONCERNS

We report a case of an 8-year-old girl with acute lymphoblastic leukaemia who developed invasive pulmonary aspergillosis complicated by CNS aspergillosis. Aspergillus was confirmed by metagenomic sequencing of pathogenic microorganisms.

DIAGNOSES

Invasive pulmonary and central nervous system aspergillosis.

INTERVENTIONS

The patient was treated with combined systemic antifungal agents (voriconazole and liposomal amphotericin B) and intrathecal injection of amphotericin B.

OUTCOMES

The treatment was well tolerated and resulted in remarkable clinical and radiological head improvements.

LESSONS

Invasive aspergillosis has a high mortality rate and requires early diagnosis and treatment. Pathogenic microbial metagenomic sequencing is a convenient method to assist in the early diagnosis of aspergillosis. Voriconazole is the drug of choice for the treatment of invasive aspergillosis. When CNS aspergillosis occurs, it can be combined with other systemic antifungal drugs and intrathecal injection of amphotericin B.

The Challenge of Diagnosing Invasive Pulmonary Aspergillosis in Children: A Review of Existing and Emerging Tools

Invasive pulmonary aspergillosis remains a major cause of morbidity and mortality for immunocompromised children, particularly for patients with acute leukaemia and those undergoing haematopoietic stem cell transplantation. Timely diagnosis, using a combination of computed tomography (CT) imaging and microbiological testing, is key to improve prognosis, yet there are inherent challenges in this process. For CT imaging, changes in children are generally less specific than those reported in adults and recent data are limited. Respiratory sampling by either bronchoalveolar lavage or lung biopsy is recommended but is not always feasible in children, and serum biomarkers, including galactomannan, have important limitations. In this review we summarise the current paediatric data on available diagnostic tests for IPA and highlight key emerging diagnostic modalities with potential for future use.

Atypical imaging patterns during lung invasive mould diseases: lessons for clinicians

Imaging of pulmonary invasive mould diseases (IMDs), which represents a cornerstone in their work-up, is mainly based on computed tomography (CT). The purpose of this review is to discuss their CT features, mainly those related to aspergillosis and mucormycosis. We will especially focus on atypical radiological presentations that are increasingly observed among non-neutropenic emerging populations of patients at risk, such as those receiving novel anticancer therapies or those in the intensive care unit. We will also discuss the interest of other available imaging techniques, mainly positron emission tomography/CT, that may play a role in the diagnosis as well as evaluation of disease extent and follow-up. We will show that any new airway-centred abnormality or caveated lesion should evoke IMDs in mildly immunocompromised hosts. Limitations in their recognition may be due to potential underlying abnormalities that increase the complexity of interpretation of lung imaging, as well as the non-specificity of imaging features. In this way, the differentials of all morphological/metabolic aspects must be kept in mind for the optimal management of patients, as well as the benefit of evaluation of the vascular status.

Radiology-based diagnosis of fungal pulmonary infections in high-risk hematology patients: are we making progress?

PURPOSE OF REVIEW

In patients with hematological malignancies, high-resolution computed tomography (CT) is the recommended imaging approach for diagnosis, staging and monitoring of invasive fungal disease (IFD) but lacks specificity. We examined the status of current imaging modalities for IFD and possibilities for more effective applications of current technology for improving the specificity of IFD diagnosis.

RECENT FINDINGS

Although CT imaging recommendations for IFD are largely unchanged in the last 20 years, improvements in CT scanner technology and image processing algorithms now allow for technically adequate examinations at much lower radiation doses. CT pulmonary angiography can improve both the sensitivity and specificity of CT imaging for angioinvasive molds in both neutropenic and nonneutropenic patients, through detection of the vessel occlusion sign (VOS). MRI-based approaches also show promise not only for early detection of small nodules and alveolar hemorrhage but can also be used to detect pulmonary vascular occlusion without radiation and iodinated contrast media. 18F-fluorodeoxyglucose (FDG) PET/computed tomography (FDG-PET/CT) is increasingly used to monitor long-term treatment response for IFD, but could become a more powerful diagnostic tool with the development of fungal-specific antibody imaging tracers.

SUMMARY

High-risk hematology patients have a considerable medical need for more sensitive and specific imaging approaches for IFD. This need may be addressable, in part, by better exploiting recent progress in CT/MRI imaging technology and algorithms to improve the specificity of radiological diagnosis for IFD.

Epidemiology, Modern Diagnostics, and the Management of Mucorales Infections

Mucormycosis is an uncommon, yet deadly invasive fungal infection caused by the Mucorales moulds. These pathogens are a WHO-assigned high-priority pathogen group, as mucormycosis incidence is increasing, and there is unacceptably high mortality with current antifungal therapies. Current diagnostic methods have inadequate sensitivity and specificity and may have issues with accessibility or turnaround time. Patients with diabetes mellitus and immune compromise are predisposed to infection with these environmental fungi, but COVID-19 has established itself as a new risk factor. Mucorales also cause healthcare-associated outbreaks, and clusters associated with natural disasters have also been identified. Robust epidemiological surveillance into burden of disease, at-risk populations, and emerging pathogens is required. Emerging serological and molecular techniques may offer a faster route to diagnosis, while newly developed antifungal agents show promise in preliminary studies. Equitable access to these emerging diagnostic techniques and antifungal therapies will be key in identifying and treating mucormycosis, as delayed initiation of therapy is associated with higher mortality.

Development and evaluation of RPA-NFO-LFT and RPA-Cas12a-LFT systems for the detection of Candida albicans

Recently, the growing number of medical interventions has led to the risk of invasive candidiasis. Among them, Candida albicans (C. albicans) infection has the highest incidence, which has led to great demand for developing early diagnosis methods. In this study, two lateral flow device based molecular assay systems, RPA-NFO-LFT and RPA-Cas12a-LFT, were established and optimized to achieve the detection of C. albicans. Firstly, efficient and specific primers for C. albicans detection were designed and screened, and the purification of amplification products was also explored. Then, many important conditions and issues for each system were investigated and discussed to improve the performances of the test strip devices in C. albicans detection. An evaluation study revealed that both systems showed favorable specificity and sensitivity in the detection of C. albicans samples with a lower detection limit of 10³ CFU ml^-1, while RPA-Cas12a-LFT is more accurate for visual interpretation and more stable toward samples that exhibit serum nucleic acid interference. Finally, the performances of RPA-NFO-LFT and RPA-Cas12a-LFT were compared with that of the conventional qPCR method. This work might provide a reference for the development of molecular assay devices in practical candidiasis diagnosis.

Invasive Fungal Infections after Liver Transplantation

Invasive fungal infections represent a major challenge in patients who underwent organ transplantation. Overall, the most common fungal infections in these patients are candidiasis, followed by aspergillosis and cryptococcosis, except in lung transplant recipients, where aspergillosis is most common. Several risk factors have been identified, which increase the likelihood of an invasive fungal infection developing after transplantation. Liver transplant recipients constitute a high-risk category for invasive candidiasis and aspergillosis, and therefore targeted prophylaxis is favored in this patient population. Furthermore, a timely implemented therapy is crucial for achieving optimal outcomes in transplanted patients. In this article, we describe the epidemiology, risk factors, prophylaxis, and treatment strategies of the most common fungal infections in organ transplantation, with a focus on liver transplantation.

Invasive aspergillosis in liver transplant recipients

BACKGROUND

Liver transplantation is increasing worldwide with underlying pathologies dominated by metabolic and alcoholic diseases in developed countries.

METHODS

We provide a narrative review of invasive aspergillosis (IA) in liver transplant (LT) recipients. We searched PubMed and Google Scholar for references without language and time restrictions.

RESULTS

The incidence of IA in LT recipients is low (1.8%), while mortality is high (∼50%). It occurs mainly early (<3 months) after LT. Some risk factors have been identified before (corticosteroid, renal, and liver failure), during (massive transfusion and duration of surgical procedure), and after transplantation (intensive care unit stay, re-transplantation, re-operation). Diagnosis can be difficult and therefore requires full radiological and clinicobiological collaboration. Accurate identification of Aspergillus species is recommended due to the cryptic species, and susceptibility testing is crucial given the increasing resistance of Aspergillus fumigatus to azoles. It is recommended to reduce the dose of tacrolimus (50%) and to closely monitor the trough level when introducing voriconazole, isavuconazole, and posaconazole. Surgery should be discussed on a case-by-case basis. Antifungal prophylaxis is recommended in high-risk patients. Environmental preventative measures should be implemented to prevent outbreaks of nosocomial aspergillosis in LT recipient units.

CONCLUSION

IA remains a very serious disease in LT patients and should be promptly sought and, if possible, prevented by clinicians when risk factors are identified.

What Is New in Pulmonary Mucormycosis?

Mucormycosis is a rare but life-threatening fungal infection due to molds of the order Mucorales. The incidence has been increasing over recent decades. Worldwide, pulmonary mucormycosis (PM) presents in the lungs, which are the third main location for the infection after the rhino-orbito-cerebral (ROC) areas and the skin. The main risk factors for PM include hematological malignancies and solid organ transplantation, whereas ROC infections are classically favored by diabetes mellitus. The differences between the ROC and pulmonary locations are possibly explained by the activation of different mammalian receptors—GRP78 in nasal epithelial cells and integrin β1 in alveolar epithelial cells—in response to Mucorales. Alveolar macrophages and neutrophils play a key role in the host defense against Mucorales. The diagnosis of PM relies on CT scans, cultures, PCR tests, and histology. The reversed halo sign is an early, but very suggestive, sign of PM in neutropenic patients. Recently, the serum PCR test showed a very encouraging performance for the diagnosis and follow-up of mucormycosis. Liposomal amphotericin B is the drug of choice for first-line therapy, together with correction of underlying disease and surgery when feasible. After a stable or partial response, the step-down treatment includes oral isavuconazole or posaconazole delayed release tablets until a complete response is achieved. Secondary prophylaxis should be discussed when there is any risk of relapse, such as the persistence of neutropenia or the prolonged use of high-dose immunosuppressive therapy. Despite these novelties, the mortality rate from PM remains higher than 50%. Therefore, future research must define the place for combination therapy and adjunctive treatments, while the development of new treatments is necessary.

New approaches to management of fever and neutropenia in high-risk patients

PURPOSE OF REVIEW

Patients receiving treatment for acute leukaemia and haematopoietic cell transplantation (HCT) have prolonged neutropenia and are at high risk of neutropenic fever, with bacterial and particularly invasive fungal infections as feared complications, possessing potentially serious consequences including intensive care admission and mortality. Concerns for these serious complications often lead to long durations of broad-spectrum antimicrobial therapy and escalation to even broader therapy if fever persists. Further, the default approach is to continue neutropenic fever therapy until count recovery, leaving many patients who have long defervesced on prolonged antibiotics.

RECENT FINDINGS

This article details recent progress in this field with particular emphasis on early discontinuation studies in resolved neutropenic fever and improved imaging techniques for the investigation of those with persistent neutropenic fever. Recent randomized controlled trials have shown that early cessation of empiric neutropenic fever therapy is well tolerated in acute leukaemia and autologous HCT patients who are clinically stable and afebrile for 72 h. Delineation of the best approach to cessation (timing and/or use of fluoroquinolone prophylaxis) and whether this approach is well tolerated in the higher risk allogeneic HCT setting is still required. Recent RCT data demonstrate utility of FDG-PET/CT to guide management and rationalize antimicrobial therapy in high-risk patient groups with persistent neutropenic fever.

SUMMARY

Acute leukaemic and autologous HCT patients with resolved neutropenic fever prior to count recovery can have empiric therapy safely discontinued or de-escalated. There is an emerging role of FDG-PET/CT to support decision-making about antibiotic and antifungal use in high-risk persistent/recurrent neutropenic fever patients.

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.

Early low-dose computed tomography with pulmonary angiography to improve the early diagnosis of invasive mould disease in patients with haematological malignancies: A pilot study

OBJECTIVE

High-resolution computed tomography (CT) is an essential diagnostic tool for invasive mould disease (IMD) in patients with haematological malignancies but is infrequently performed in the first 72 h of neutropenic fever until after chest X-ray (CXR). We hypothesised that early (< 48 h) low-dose CT (LD-CT; 90% reduction in radiation dose) combined with CT pulmonary angiography (CTPA) to detect the venous occlusion sign (VOS) inside suspected infiltrates could improve IMD diagnosis.

METHODS

We prospectively studied 68 consecutive adult patients undergoing treatment for haematological malignancies who developed fever following chemotherapy or haematopoietic stem cell transplantation. Within 48 h of fever, patients underwent a standard CXR followed by LD-CT imaging and CTPA if eligible based on baseline imaging findings; the same protocol was performed in 42/68 (61.7%) of patients at day 7 follow-up. The diagnostic performance of CT signs for EORTC/MSG-defined proven, probable, and possible IMD was analysed at both imaging periods.

RESULTS

The baseline LD-CT was positive for abnormalities in 43/68 (63%) of patients within 48 h of fever and 35/42 (83%) of patients at the follow-up exam. Amongst these 43 patients, CTPA was performed in 17/43 (39%) and in 18/35 (51%) at D + 7 follow-up. A positive VOS was associated with the highest estimated positive likelihood ratio for EORTC/MSG-defined proven, probable, or possible IMD at baseline (20.6; 95% CI 1.4-311.2) and at day 7 follow-up (19.0; 95% CI 0.93-300.8) followed by the baseline non-contrast enhanced hypodense sign (18.3; 0.93-361.7), reverse halo (11.0; 0.47-256.5), halo sign (8.68;3.13-24.01) and air-crescent sign at day 7 (16.7; 0.93-301.0). However, a negative VOS was the only CT sign at baseline or day 7 associated with sufficiently low negative likelihood ratio (0.05;0.001-0.8) to possibly support ruling-out IMD in patients with positive CT findings.

CONCLUSIONS

Early LD-CT combined with CTPA shows promise for improving the early radiographic diagnosis of IMD.

Invasive aspergillosis in solid organ transplant patients: diagnosis, prophylaxis, treatment, and assessment of response

BACKGROUND

Invasive aspergillosis (IA) is a rare complication in solid organ transplant (SOT) recipients. Although IA has significant implications on graft and patient survival, data on diagnosis and management of this infection in SOT recipients are still limited.

METHODS

Discussion of current practices and limitations in the diagnosis, prophylaxis, and treatment of IA and proposal of means of assessing treatment response in SOT recipients.

RESULTS

Liver, lung, heart or kidney transplant recipients have common as well as different risk factors to the development of IA, thus each category needs a separate evaluation. Diagnosis of IA in SOT recipients requires a high degree of awareness, because established diagnostic tools may not provide the same sensitivity and specificity observed in the neutropenic population. IA treatment relies primarily on mold-active triazoles, but potential interactions with immunosuppressants and other concomitant therapies need special attention.

CONCLUSIONS

Criteria to assess response have not been sufficiently evaluated in the SOT population and CT lesion dynamics, and serologic markers may be influenced by the underlying disease and type and severity of immunosuppression. There is a need for well-orchestrated efforts to study IA diagnosis and management in SOT recipients and to develop comprehensive guidelines for this population.

Core Recommendations for Antifungal Stewardship: A Statement of the Mycoses Study Group Education and Research Consortium

In recent years, the global public health community has increasingly recognized the importance of antimicrobial stewardship (AMS) in the fight to improve outcomes, decrease costs, and curb increases in antimicrobial resistance around the world. However, the subject of antifungal stewardship (AFS) has received less attention. While the principles of AMS guidelines likely apply to stewarding of antifungal agents, there are additional considerations unique to AFS and the complex field of fungal infections that require specific recommendations. In this article, we review the literature on AMS best practices and discuss AFS through the lens of the global core elements of AMS. We offer recommendations for best practices in AFS based on a synthesis of this evidence by an interdisciplinary expert panel of members of the Mycoses Study Group Education and Research Consortium. We also discuss research directions in this rapidly evolving field. AFS is an emerging and important component of AMS, yet requires special considerations in certain areas such as expertise, education, interventions to optimize utilization, therapeutic drug monitoring, and data analysis and reporting.

Clinical characteristics and CT manifestations of invasive pulmonary aspergillosis in hospitalised patients with systemic lupus erythematosus

AIM

To investigate clinical and computed tomography (CT) findings of invasive pulmonary aspergillosis (IPA) in patients with systemic lupus erythematosus (SLE) and to explore the relationships of CT findings with clinical characteristics and outcomes.

MATERIALS AND METHODS

Clinical and CT findings of 14 SLE patients with proven (n=4) and probable (n=10) IPA between January 2006 and April 2013 were reviewed retrospectively and related to patients' outcomes.

RESULTS

All patients (mean age, 42.3 ± 15.1 years; 11 women, three men) had active SLE, prior corticosteroid, and/or immunosuppressive therapy. Dominant CT findings performed within 10 days of the clinical onset consisted of nodules/masses (100%, 14/14), consolidations (92.9%, 13/14), and ground-glass opacity (85.7%, 12/14). Bilateral, multilobar, and upper-lobe involvement was common. Regardless of dominant patterns, the halo, reversed halo, air-crescent, hypodense, and feeding vessel signs were found in 12 (85.7%), one (7.1%), three (21.3%), seven (50%), and seven (50%) patients, respectively. There was no significant difference in CT findings between the IPA alone (n=5) and co-infection (n=9) groups and between survived (n=4) and non-survived (n=10) patients. The IPA-alone group more frequently had alcohol consumption (p=0.018), haemoptysis (p=0.023), and disseminated aspergillosis (p=0.027) than did the co-infection group. Non-survived patients tended to be older and have a history of recent hospitalisation.

CONCLUSIONS

IPA is a rare, life-threatening disease affecting SLE patients in the early course of disease with high disease activity requiring corticosteroid and/or immunosuppressive therapy. Dominant CT findings are characteristics of angio-invasive form with a high frequency of the halo sign and bilateral, multilobar, and upper-lobe involvement.

Detection of invasive pulmonary aspergillosis in mice using lung perfusion single-photon emission computed tomography with [99mTc]MAA

There is an urgent need for development of better diagnostic strategies to improve outcomes in patients with invasive pulmonary aspergillosis (IPA). We hypothesized that lung perfusion single-photon emission computed tomography (SPECT) may be more sensitive and specific than computed tomography (CT) of the chest for detection of IPA because it is an angioinvasive pulmonary infection with characteristics that are different from those of bacterial pneumonia. We used SPECT with injection of technetium-99m-labeled macroaggregated albumin ([99mTc]MAA) to measure pulmonary perfusion in noninfected mice, mice with IPA, and mice with bacterial pneumonia. Histopathologic analysis was performed to evaluate the correlation between the perfusion defect and mould invasion. We also attempted to quantitatively evaluate the SPECT images to identify differences in decreased perfusion levels in affected areas in the mouse lung. Histopathologic analysis in the IPA mouse model showed a clear match between areas with a perfusion defect and the presence of mold, indicating that the location of the perfusion defect on a SPECT image reflects angioinvasion of the mould in the lungs. Some of these perfusion defects could be seen before appearance of the infiltrate of CT images. Quantitative analysis confirmed that perfusion in the affected areas was significantly decreased in the IPA model but not in the bacterial pneumonia model (P < .0001). This imaging method may be preferable to the alternative methods presently used to identify the presence of mold in a patient's lungs.

Diagnosis and treatment of invasive fungal infections: looking ahead

Improved standards of care depend on the development of new laboratory diagnostic and imaging procedures and the development of new antifungal compounds. Immunochromatography technologies have led to the development of lateral flow devices for the diagnosis of cryptococcal meningitis and invasive aspergillosis (IA). Similar devices are being developed for the detection of histoplasmosis that meet the requirements for speed (∼15 min assay time) and ease of use for point-of-care diagnostics. The evolution of molecular tools for the detection of fungal pathogens has been slow but the introduction of new nucleic acid amplification techniques appears to be helpful, for example T2Candida. An Aspergillus proximity ligation assay has been developed for a rapid near-patient bedside diagnosis of IA. CT remains the cornerstone for radiological diagnosis of invasive pulmonary fungal infections. MRI of the lungs may be performed to avoid radiation exposure. MRI with T2-weighted turbo-spin-echo sequences exhibits sensitivity and specificity approaching that of CT for the diagnosis of invasive pulmonary aspergillosis. The final part of this review looks at new approaches to drug discovery that have yielded new classes with novel mechanisms of action. There are currently two new classes of antifungal drugs in Phase 2 study for systemic invasive fungal disease and one in Phase 1. These new antifungal drugs show promise in meeting unmet needs with oral and intravenous formulations available and some with decreased potential for drug-drug interactions. Novel mechanisms of action mean these agents are not susceptible to the common resistance mechanisms seen in Candida or Aspergillus. Modification of existing antifungal susceptibility testing techniques may be required to incorporate these new compounds.

Pre-transplant sTIM-3 levels may have a predictive impact on transplant outcome in acute leukemia patients

Objectives: T-cell immunoglobulin and mucin domain-containing protein-3 (TIM-3) is considered as a negative regulator of T-cell driven immune response. This study is planned to investigate the prognostic role of pre-transplant soluble TIM-3 (sTIM-3) levels in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Methods: Pre-transplant serum sTIM-3 levels were measured in 177 allo-HSCT recipients [median age: 36(16-66) years; male/female: 111/66]. Results: Pre-transplant sTIM-3 levels were significantly higher in acute myeloid leukemia (AML) patients compared to acute lymphoblastic leukemia (ALL) patients (p = 0.01). Pre-transplant sTIM-3 levels were significantly lower in patients with abnormal cytogenetics (p = 0.017). Pre-transplant sTIM-3 levels were significantly higher in patients who developed viral hemorrhagic cystitis (p = 0.034). A positive correlation was demonstrated between sTIM-3 levels and acute graft versus host disease (GvHD) grade (p = 0.013; r = 0.299). Overall survival (OS) was not statistically different between low- and high-TIM-3 groups (%35.2 vs %20.4; p > 0.05). Primary diagnosis (p = 0.042), sinusoidal obstruction syndrome (p < 0.001), acute GvHD (p = 0.001), chronic GvHD (p = 0.009) and post-transplant relapse (p = 0.003) represented significant impact on OS. Discussion: Increased sTIM-3 levels in AML patients seem to be compatible with the previous reports. The inhibitor role of TIM-3 in cellular immune response may be a possible explanation for the association of sTIM-3 with viral infections and GvHD. However, the main challenge remains to be the ambiguous association of pre-transplant sTIM-3 levels and post-transplant complications, as allo-HSCT recipients are expected to represent donor genetic features in the post-transplant setting. Conclusion: Further studies are warranted to clarify the particular role of sTIM-3 in the allo-HSCT setting.

Galactosaminogalactan secreted from Aspergillus fumigatus and Aspergillus flavus induces platelet activation

Platelets are meanwhile recognized as versatile elements within the immune system and appear to play a key role in the innate immune response to pathogens including fungi. Previous experiments revealed platelet activation by direct contact with the hyphal-associated polysaccharide galactosaminogalactan (GAG). Since secreted fungal products may also be relevant and trigger immune reactions or thrombosis, we screened culture supernatants (SN) of human-pathogenic fungi for their capacity to activate platelets. For that purpose, platelets were incubated with SN from various fungal species; platelet activation and GAG deposition on the surface of platelets were detected by flow cytometry and electron and confocal microscopy, Culture supernatants of Aspergillus fumigatus and flavus isolates were potent platelet stimulators in a dose- and time-dependent manner, while SN of other Aspergillus species and all tested mucormycete species did not significantly induce platelet activation. The capacity of culture SN to activate platelets was dependent on fungal production of GAG and deposition of secreted GAG on the platelet surface; supernatants from mucormycetes or mutants of A. fumigatus lacking GAG secretion did not affect platelet activity. These results suggest that invading fungi can stimulate platelets not only locally through direct interactions with fungal hyphae, but can also act over a certain distance through secreted GAG.

CT Halo sign: A systematic review

PURPOSE

The CT Halo sign or Halo sign (HS) refers to ground-glass opacity surrounding a nodule or mass in the lung parenchyma. We conducted a systematic review to find the etiological associations of HS. We also evaluated the diagnostic performances of HS for invasive fungal infections (IFI) in immunosuppressed patients.

METHOD

The systematic review was conducted as per PRISMA guidelines. We searched the PubMed and EMBASE database till June 2018 without any restrictions. Only case reports, case series and original articles published in English language were included. A database created from the electronic searches was compiled and subsequent analysis was done. [PROSPERO registration: CRD42018094739] RESULTS: 168 studies were eligible, which included 51 case reports, 15 prospective studies, 102 retrospective studies. A total of 1977 patients (out of 6371) with HS were identified with age range between <1year-94years. The most common diagnosis in the immunosuppressed, mixed, immunocompetent and not specified groups were IFI (86.9 %, n = 1194), Cryptococcosis (51.6 %, n = 124), Cryptococcosis (40 %, n = 20) and lung neoplasms (81.8 %, n = 36) respectively. 14 studies (11 retrospective, 3 prospective) were included in quantitative analysis. The pooled sensitivity(sn), specificity(sp) and odd's ratio (OR) of HS for diagnosing IFI were 50.4 %, 91 % and 6.61 respectively. Also, HS could not reliably differentiate IPA from mucormycosis in the pooled analysis.

CONCLUSIONS

HS can be seen in a large number of diverse conditions both in immunosuppressed and immunocompetent population. In immunosuppressed patients HS is specific for IFI but cannot rule it out. Additionally, it cannot reliably distinguish between IPA and mucormycosis.

Aspergillus fumigatus and Aspergillosis in 2019

Aspergillus fumigatus is a saprotrophic fungus; its primary habitat is the soil. In its ecological niche, the fungus has learned how to adapt and proliferate in hostile environments. This capacity has helped the fungus to resist and survive against human host defenses and, further, to be responsible for one of the most devastating lung infections in terms of morbidity and mortality. In this review, we will provide (i) a description of the biological cycle of A. fumigatus; (ii) a historical perspective of the spectrum of aspergillus disease and the current epidemiological status of these infections; (iii) an analysis of the modes of immune response against Aspergillus in immunocompetent and immunocompromised patients; (iv) an understanding of the pathways responsible for fungal virulence and their host molecular targets, with a specific focus on the cell wall; (v) the current status of the diagnosis of different clinical syndromes; and (vi) an overview of the available antifungal armamentarium and the therapeutic strategies in the clinical context. In addition, the emergence of new concepts, such as nutritional immunity and the integration and rewiring of multiple fungal metabolic activities occurring during lung invasion, has helped us to redefine the opportunistic pathogenesis of A. fumigatus.

Fungal Infections of the Stem Cell Transplant Recipient and Hematologic Malignancy Patients

Despite advances in chemotherapy and supportive care, morbidity and mortality remain high for patients with hematologic malignancies (HMs). Those who require hematopoietic stem cell transplantation (HSCT) often require significant immunosuppression and are subject to a variety of complications. These patients carry multiple risk factors for infectious complications, including the development of invasive fungal infections, compared with the general population. Because antifungal prophylaxis has been widely adopted, there has been a shift away from invasive candidiasis toward invasive mold infections, including breakthrough infections. For patients with HM and HSCT, we outline the epidemiology, manifestations, diagnosis, and treatment of invasive fungal infections.

Diagnosis of invasive fungal disease in children: a narrative review

Introduction: Invasive fungal diseases (IFD) represent important causes of morbidity and mortality in pediatrics. Early diagnosis and treatment of IFD is associated with better outcome and this entails the need to use fast and highly sensitive and specific methods that can support clinicians in the management of IFD.Areas covered: A narrative review was performed on conventional diagnostic methods such as culture, microscopy and histopathology are still gold standard but are burdened by a lack of sensitivity and specificity; on the other hand, imaging and noninvasive antigen-based such as beta-D-glucan, galactomannan and molecular biomarkers are the most convenient nonculture methods for diagnosis and monitoring effects of therapy. Aim of the present review is to summarize what is available in these fields at end of the second decade of the third millennium and look for future perspectives.Expert opinion: Promising and useful diagnostic methods have been applied in infectious disease diagnosis in clinical practice or in designing platforms. Unfortunately, most of them are not standardized or validated in pediatric population. However, clinicians should be aware of all innovative diagnostic tools to use in combination with conventional diagnostic methods for a better management of pathology and patient.

Beyond biomarkers: How enhanced CT imaging can improve the diagnostic-driven management of invasive mould disease

CT imaging remains an essential diagnostic test for identification, staging and management of invasive mould infection (IMI) in patients with hematological malignancies. Yet the limited specificity of standard CT imaging can drive excessive antifungal use in patients, especially when more definitive diagnosis cannot be established through microbiology or invasive diagnostic procedures. CT pulmonary angiography (CTPA) is a complimentary, non-invasive approach to standard CT that allows for direct visualization of pulmonary arteries inside infiltrates for signs of angioinvasion, vessel destruction and vessel occlusion. Experience from several centers that are using CTPA as part of a standard diagnostic protocol for IMI suggests that a positive vessel occlusion sign (VOS) is the most sensitive and a specific sign of IMI in both neutropenic and non-neutropenic patients. CTPA is particularly useful in patients who develop suspected breakthrough IMI during antifungal prophylaxis because, unlike serum and/or BAL galactomannan and polymerase chain reaction (PCR) testing, the sensitivity is not reduced by antifungal therapy. A negative VOS may also largely rule-out the presence of IMI, supporting earlier discontinuation of empirical therapy. Future imaging protocols for IMI in patients with hematological malignancies will likely replace standard chest X-rays in favor of early low radiation dose CT exams for screening, with characterization of the lesions by CTPA and routine follow-up using functional/metabolic imaging such as 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (FDG-PET/CT) to assess treatment response. Hence, enhanced CT imaging techniques can improve the diagnostic-driven management of IMI management in high-risk patients with hematological malignancies.

A clinical approach to respiratory disease in patients with hematological malignancy, with a focus on respiratory infection

Respiratory complications, in particular infections, are common in the setting of hematological malignancy and after hematopoetic stem cell transplant. The symptoms can be nonspecific; therefore, it can be difficult to identify and treat the cause. However, an understanding of the specific immune defect, clinical parameters such as speed of onset, and radiological findings, allows the logical diagnostic and treatment plan to be made. Radiological findings can include consolidation, nodules, and diffuse changes such as ground glass and tree-in-bud changes. Common infections that induce these symptoms include bacterial pneumonia, invasive fungal disease, Pneumocystis jirovecii and respiratory viruses. These infections must be differentiated from inflammatory complications that often require immune suppressive treatment. The diagnosis can be refined with the aid of investigations such as bronchoscopy, computed tomography (CT) guided lung biopsy, culture, and serological tests. This article gives a schema to approach patients with respiratory symptoms in this patient group; however, in the common scenario of a rapidly deteriorating patient, treatment often has to begin empirically, with the aim to de-escalate treatment subsequently after targeted investigations.

Saprochaete clavata infections in patients undergoing treatment for haematological malignancies: A report of a monocentric outbreak and review of the literature

Saprochaete clavata is a rare cause of fungaemia with deep organ involvement in patients with haematological malignancies with reported mortality rates of 60%-80%. We describe four cases of S clavata infection in a haematology unit over several months that were treated with voriconazole-based regimens. We also review the literature on factors that could contribute to earlier recognition and effective treatment of S clavata. We included all cases of culture-positive S clavata from sterile sites with associated signs of infection in patients undergoing treatment for a haematological malignancy. Isolates were identified by MALDI-TOF MS, and spectrum profiles were used to prepare clustering analysis of isolates. Susceptibility testing was performed using a commercial microtitre methods. Saprochaete clavata was isolated from the bloodstream in three cases and bronchial alveolar lavage (BAL) fluid in one case. Clustering analysis suggested strains of S clavata were clonal without evidence of divergence although a common source was not identified. Susceptibility testing yielded elevated MICs to fluconazole (8 mg/L) and echinocandins (>1-8 mg/L). All patients were treated with voriconazole-based regimens resulting in survival of 3/4 patients, who continued chemotherapy for their underlying malignancy without evidence of relapse. Saprochaete clavata is a rare but aggressive cause of breakthrough yeast infection in patients undergoing treatment for haematological malignancies, particularly patients with a prior history of echinocandin treatment. Timely initiation of appropriate treatment, aided by more rapid identification in microbiology laboratory, can reduce the risk of deep organ dissemination and patient death.

Invasive mould infections in solid organ transplant patients: modifiers and indicators of disease and treatment response

PURPOSE

Invasive mould infections, in particular invasive aspergillosis (IA), are comparatively frequent complications of immunosuppression in patients undergoing solid organ transplantation (SOT). Guidelines provide recommendations as to the procedures to be carried out to diagnose and treat IA, but only limited advice for SOT recipients.

METHODS

Literature review and expert consensus summarising the existing evidence related to prophylaxis, diagnosis, treatment and assessment of response to IA and infections by Mucorales in SOT patients RESULTS: Response to therapy should be assessed early and at regular intervals. No indications of improvement should lead to a prompt change of the antifungal treatment, to account for possible infections by Mucorales or other moulds such as Scedosporium. Imaging techniques, especially CT scan and possibly angiography carried out at regular intervals during early and long-term follow-up and coupled with a careful clinical diagnostic workout, should be evaluated as diagnostic tools and outcome predictors, and standardised to improve therapy monitoring. The role of biomarkers such as the galactomannan test and PCR, as well as selected inflammation parameters, has not yet been definitively assessed in the SOT population and needs to be studied further. The therapeutic workup should consider a reduction of immunosuppressive therapy.

CONCLUSIONS

The role of immunosuppression and immune tolerance mechanisms in the response to invasive fungal infection treatment is an important factor in the SOT population and should not be underestimated. The choice of the antifungal should consider not only their toxicity but also their effects on the immune system, two features that are intertwined.

Diagnostic-driven management of invasive fungal disease in hematology in the era of prophylaxis and resistance emergence: Dutch courage?

Patients receiving intensive anti-leukemic treatment or recipients of allogeneic hematopoietic stem cell transplantation (HSCT) are prone to develop invasive fungal disease caused by both Aspergillus and non-Aspergillus moulds. Overall mortality following invasive mould disease (IMD) is high; adequate and timely antifungal treatment seems to ameliorate the outcome, yet early diagnosis in the haematological patient remains a challenge for most clinicians. Prophylaxis and the empiric addition of antifungal therapy to neutropaenic patients with fever persisting or recurring during broad-spectrum antibiotic treatment is therefore standard of care in many institutions. However, aside from the potential for overtreatment and important side effects, the emergence of resistance to medical triazoles in Aspergillus fumigatus poses a risk for inadequate initial treatment. Initial voriconazole therapy in patients with azole-resistant invasive aspergillosis was recently shown to be associated with a 23% increased mortality rate compared to the patients with azole-susceptible infection, despite changing to appropriate antifungal therapy once resistance was detected. Moreover, fever is not always present with IMD; therefore, cases may be missed when relying solely on this symptom for starting diagnostic procedures and antifungal treatment. At our institution, a diagnostic-driven treatment approach for IMD was implemented relying on clinical but also laboratory markers to start antifungal treatment. We describe the basis and clinical implementation of our diagnostic-driven approach in this review.

ESCMID-ECMM guideline: diagnosis and management of invasive aspergillosis in neonates and children

SCOPE

Presenting symptoms, distributions and patterns of diseases and vulnerability to invasive aspergillosis (IA) are similar between children and adults. However, differences exist in the epidemiology and underlying conditions, the usefulness of newer diagnostic tools, the pharmacology of antifungal agents and in the evidence from interventional phase 3 clinical trials. Therefore, the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) and the European Confederation of Medical Mycology (ECMM) have developed a paediatric-specific guideline for the diagnosis and management of IA in neonates and children.

METHODS

Review and discussion of the scientific literature and grading of the available quality of evidence was performed by the paediatric subgroup of the ESCMID-ECMM-European Respiratory Society (ERS) Aspergillus disease guideline working group, which was assigned the mandate for the development of neonatal- and paediatric-specific recommendations.

QUESTIONS

Questions addressed by the guideline included the epidemiology of IA in neonates and children; which paediatric patients may benefit from antifungal prophylaxis; how to diagnose IA in neonates and children; which antifungal agents are available for use in neonates and children; which antifungal agents are suitable for prophylaxis and treatment of IA in neonates and children; what is the role of therapeutic drug monitoring of azole antifungals; and which management strategies are suitable to be used in paediatric patients. This guideline provides recommendations for the diagnosis, prevention and treatment of IA in the paediatric population, including neonates. The aim of this guideline is to facilitate optimal management of neonates and children at risk for or diagnosed with IA.

Utility of CT assessment in hematology patients with invasive aspergillosis: a post-hoc analysis of phase 3 data

BACKGROUND

Pulmonary computed tomography (CT) scans are commonly used as part of the clinical criteria in diagnostic workup of invasive fungal diseases like invasive aspergillosis, and may identify radiographic abnormalities, such as halo signs or air-crescent signs. We assessed the diagnostic utility of CT assessment in patients with hematologic malignancies or those who had undergone allogeneic hematopoietic stem cell transplantation in whom invasive aspergillosis was suspected.

METHODS

This post-hoc analysis assessed data from a prospective, multicenter, international trial of voriconazole (with and without anidulafungin) in patients with suspected invasive aspergillosis (IA; proven, probable, or possible, using 2008 European Organisation for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria) [NCT00531479]. Eligible patients received at least one baseline lung CT scan.

RESULTS

Of 395 patients included in this post-hoc analysis, 240 patients (60.8%) had 'confirmed' proven (9/240, 3.8%) or probable (231/240, 96.3%) invasive aspergillosis (cIA) and 155 patients (39.2%) had 'non-confirmed' invasive aspergillosis (all nIA; all possible IA (de Pauw et al., Clin Infect Dis 46:1813-21, 2008)). Mean age was 52.3 and 50.5 years, 56.3 and 60.0% of patients were male, and most patients were white (71.7 and 71.0%) in the cIA and nIA populations, respectively. Median baseline galactomannan was 1.4 (cIA) and 0.2 (nIA), mean Karnofsky score was 65.3 (cIA) and 66.8 (nIA), and mean baseline platelet count was 48.0 (cIA) and 314.1 (nIA). Pulmonary nodules (46.8% of all patients), bilateral lung lesions (37.5%), unilateral lung lesions (28.4%), and consolidation (24.8%) were the most common radiographic abnormalities. Ground-glass attenuation (cIA: 24.2%; nIA: 11.6%; P < 0.01) and pulmonary nodules (cIA: 52.5%; nIA: 38.1%; P < 0.01) were associated with cIA. Other chest CT scan abnormalities (including halo signs and air-crescent signs) at baseline in patients with hematologic malignancy or hematopoietic stem cell transplantation, and suspected IA, were not associated with cIA.

CONCLUSIONS

These findings highlight the limitations in the sensitivity of chest CT scans for the diagnosis of IA, and reinforce the importance of incorporating other available clinical data to guide management decisions on individual patients, including whether empirical treatment is reasonable, pending full evaluation.

TRIAL REGISTRATION

NCT00531479 (First posted on ClinicalTrials.gov on September 18, 2007).

The role of Aspergillus fumigatus polysaccharides in host-pathogen interactions

Aspergillus fumigatus is a saprophytic mold that can cause infection in patients with impaired immunity or chronic lung diseases. The polysaccharide-rich cell wall of this fungus is a key point of contact with the host immune system. The availability of purified cell wall polysaccharides and mutant strains deficient in the production of these glycans has revealed that these glycans play an important role in the pathogenesis of A. fumigatus infections. Herein, we review our current understanding of the key polysaccharides present within the A. fumigatus cell wall, and their interactions with host cells and secreted factors during infection.

Diagnostic work up to assess early response indicators in invasive pulmonary aspergillosis in adult patients with haematologic malignancies

In immunocompromised patients with acute leukaemia as well as in allogeneic hematopoietic stem cell transplant patients, pulmonary lesions are commonly seen. Existing guidelines provide useful algorithms for diagnostic procedures and treatment options, but they do not give recommendations on how to evaluate early success or failure and if or when it is best to change therapy. Here, we review the diagnostic techniques currently used in association with clinical findings and propose an approach using a combination of computer tomography, clinical and all available biomarkers and inflammation parameters, especially those positive at baseline, to assess early response in invasive pulmonary aspergillosis. Computed tomography scans should be carried out at regular intervals during early and long-term follow-up. Imaging on day seven, or even earlier in clinically unstable patients, combined with an additional testing of biomarkers and inflammatory markers in between, is needed for a reliable assessment at day 14. If no improvement is seen after 2 weeks of therapy or the clinical condition is deteriorating, a change of antifungal therapy should be considered. Alleged breakthrough infections or treatment failure should undergo early diagnostic workup, including tissue biopsies when possible, to retrieve fungal cultures for resistance testing.

Invasive Aspergillosis in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated AST-IDCOP guidelines provide information on epidemiology, diagnosis, and management of Aspergillus after organ transplantation. Aspergillus is the most common invasive mold infection in solid-organ transplant (SOT) recipients, and it is the most common invasive fungal infection among lung transplant recipients. Time from transplant to diagnosis of invasive aspergillosis (IA) is variable, but most cases present within the first year post-transplant, with shortest time to onset among liver and heart transplant recipients. The overall 12-week mortality of IA in SOT exceeds 20%; prognosis is worse among those with central nervous system involvement or disseminated disease. Bronchoalveolar lavage galactomannan is preferred for the diagnosis of IA in lung and non-lung transplant recipients, in combination with other diagnostic modalities (eg, chest CT scan, culture). Voriconazole remains the drug of choice to treat IA, with isavuconazole and lipid formulations of amphotericin B regarded as alternative agents. The role of combination antifungals for primary therapy of IA remains controversial. Either universal prophylaxis or preemptive therapy is recommended in lung transplant recipients, whereas targeted prophylaxis is favored in liver and heart transplant recipients. In these guidelines, we also discuss newer antifungals and diagnostic tests, antifungal susceptibility testing, and special patient populations.

FDG-PET/CT in managing infection in patients with hematological malignancy: clinician knowledge and experience in Australia

PET/CT is useful for investigation of neutropenic fever (NF) and potential invasive fungal infection (IFI) in those with hematological malignancies (HM). An online survey evaluating the utility and current practices regarding PET/CT scanning for investigation of NF was distributed to infectious diseases (ID) clinicians and hematologists via email lists hosted by key professional bodies. One-hundred and forty-five clinicians responded (120 ID; 25 hematologists). Access to PET/CT was fair but timeliness of investigation was limited (within 3 days in 35% and 46% of ID and hematology respondents, respectively). Among those with experience with PET/CT for infection (n = 109), 40% had utilized PET/CT for prolonged NF and 20% for diagnosing IFI. The majority of respondents indicated the desire to utilize PET/CT more frequently for infection indications. There is a strong desire among surveyed Australian clinicians to use PET/CT for prolonged NF and potential IFI. However, access to PET/CT is a current barrier to uptake.

Breakthrough invasive fungal diseases in acute myeloid leukemia patients receiving mould active triazole primary prophylaxis after intensive chemotherapy: An Italian consensus agreement on definitions and management

In the attempt to establish definitions and provide shared approaches to breakthrough invasive fungal diseases (br-IFD) in acute myeloid leukemia (AML) patients submitted to intensive chemotherapy and receiving triazoles as mould active primary antifungal prophylaxis (MA-PAP), literature on br-IFD in AML patients receiving triazoles MA-PAP was reviewed and a Consensus Development Conference Project was convened. The following four candidate key-questions were generated and formed the set of questions of the present document: "definition of br-IFD," "diagnostic strategy during MA-PAP to detect br-IFD," "possible causes of MA-PAP failure," "management of br-IFD."

Galactosaminogalactan (GAG) and its multiple roles in Aspergillus pathogenesis

Aspergillus spp and particularly the species Aspergillus fumigatus are the causative agents of invasive aspergillosis, a progressive necrotizing pneumonia that occurs in immunocompromised patients. The limited efficacy of currently available antifungals has led to interest in a better understanding of the molecular mechanisms underlying the pathogenesis of invasive aspergillosis in order to identify new therapeutic targets for this devastating disease. The Aspergillus exopolysaccharide galactosaminogalactan (GAG) plays an important role in the pathogenesis of experimental invasive aspergillosis. The present review article summarizes our current understanding of GAG composition and synthesis and the molecular mechanisms whereby GAG promotes virulence. Promising directions for future research and the prospect of GAG as both a therapy and therapeutic target are reviewed.

Development and Applications of Prognostic Risk Models in the Management of Invasive Mold Disease

Prognostic models or risk scores are frequently used to aid individualize risk assessment for diseases with multiple, complex risk factors and diagnostic challenges. However, relatively little attention has been paid to the development of risk models for invasive mold diseases encountered in patients with hematological malignancies, despite a large body of epidemiological research. Herein we review recent studies that have described the development of prognostic models for mold disease, summarize our experience with the development and clinical use of one such model (BOSCORE), and discuss the potential impact of prognostic risk scores for individualized therapy, diagnostic and antifungal stewardship, as well as clinical and epidemiological research.

Improving the rates of Aspergillus detection: an update on current diagnostic strategies

INTRODUCTION

The spectrum of disease caused by Aspergillus spp. is dependent on the immune system of the host, and ranges from invasive aspergillosis (IA) to chronic pulmonary aspergillosis (CPA). Early and reliable diagnosis of Aspergillus disease is important to decrease associated morbidity and mortality. Areas covered: The following review will give an update on current diagnostic strategies for the diagnosis of IA and CPA. Expert commentary: Several new diagnostics for IA (including point-of-care tests) are now available to complement galactomannan testing. In particular, immunoPET/MRI imaging may be a promising approach for diagnosing IA in the near future. Notably, nearly all new biomarkers and tests for IA have been evaluated in the hematology setting only. Validation of biomarkers and tests is therefore needed for the increasing proportion of patients who develop IA outside the hematology setting. As an important first step, reliable definitions of IA are needed for non-hematology settings as clinical presentation and radiologic findings differ in these settings. CPA diagnosis is based on a combination of radiological findings in chest CT, mycological evidence (e.g. by the Aspergillus-specific IgG assay), exclusion of alternative diagnosis and chronicity. ([18F]FDG) PET/CT and immuno PET/MRI imaging are promising new imaging approaches.

Diagnosis of invasive fungal diseases in haematology and oncology: 2018 update of the recommendations of the infectious diseases working party of the German society for hematology and medical oncology (AGIHO)

Invasive fungal diseases (IFD) are a primary cause of morbidity and mortality in patients with haematological malignancies. These infections are mostly life-threatening and an early diagnosis and initiation of appropriate antifungal therapy are essential for the clinical outcome. Most commonly, Aspergillus and Candida species are involved. However, other Non-Aspergillus moulds are increasingly identified in case of documented IFD. For definite diagnosis of IFD, a combination of diagnostic tools have to be applied, including conventional mycological culture and non-conventional microbiological tests such as antibody/antigen and molecular tests, as well as histopathology and radiology. Although varying widely in cancer patients, the risk of invasive fungal infection is highest in those with allogeneic stem cell transplantation and those with acute leukaemia and markedly lower in patients with solid cancer. Since the last edition of Diagnosis of Invasive Fungal Diseases recommendations of the German Society for Hematology and Oncology in 2012, integrated care pathways have been proposed for the management and therapy of IFDs with either a diagnostic driven strategy as opposed to a clinical or empirical driven strategy. This update discusses the impact of this additional evidence and effective revisions.

[Pulmonary infiltrates in haematological patients]

BACKGROUND

Pulmonary complications are frequent in haematologic patients.

METHOD

This review article summarizes the outcome of a discussion that took place during an expert meeting on the subject of pulmonary infiltrates.

RESULTS AND CONCLUSIONS

The most common causes of pulmonary infiltrates in haematologic patients are bacterial infections. Viral infections are subject to relevant seasonal variations, but they may also cause an important proportion of pulmonary infiltrates. Microbiological examination of respiratory tract material (if possible, bronchoalveolar lavage, BAL) is the most important diagnostic procedure. Particularly in the case of prolonged (> 7 days) neutropenia, the likelihood of infiltrates being caused by fungal infections increases. For a differential diagnosis, however, also non-infectious causes, e.g. drug-induced infiltrates, have to be taken into consideration. The diagnostic workup, however, should not delay a timely start of an adequate antimicrobial therapy.

The evolving landscape of new diagnostic tests for invasive aspergillosis in hematology patients: strengths and weaknesses

PURPOSE OF REVIEW

The diagnosis of invasive aspergillosis in hematologic patients is a complex composite of clinical preconditions and features, imaging findings, biomarker combinations from appropriate clinical samples and microbiological and/or histological findings.

RECENT FINDINGS

Recent developments in the evolving landscape of diagnostic tests for invasive aspergillosis in adult hematology patients are highlighted.

SUMMARY

Novel approaches and tools are currently under development. Focusing optimized diagnostic performance, in particular the combination of biomarkers from appropriate clinical samples, improved diagnostic performance distinctly.

Is a biomarker-based diagnostic strategy for invasive aspergillosis cost effective in high-risk haematology patients?

Empirical antifungal therapy is frequently used in hematology patients at high risk of invasive aspergillosis (IA), with substantial cost and toxicity. Biomarkers for IA aim for earlier and more accurate diagnosis and targeted treatment. However, data on the cost-effectiveness of a biomarker-based diagnostic strategy (BDS) are limited. We evaluated the cost effectiveness of BDS using results from a randomized controlled trial (RCT) and individual patient costing data. Data inputs derived from a published RCT were used to construct a decision-analytic model to compare BDS (Aspergillus galactomannan and PCR on blood) with standard diagnostic strategy (SDS) of culture and histology in terms of total costs, length of stay, IA incidence, mortality, and years of life saved. Costs were estimated for each patient using hospital costing data to day 180 and follow-up for survival was modeled to five years using a Gompertz survival model. Treatment costs were determined for 137 adults undergoing allogeneic hematopoietic stem cell transplant or receiving chemotherapy for acute leukemia in four Australian centers (2005-2009). Median total costs at 180 days were similar between groups (US$78,774 for SDS [IQR US$50,808-123,476] and US$81,279 for BDS [IQR US$59,221-123,242], P = .49). All-cause mortality was 14.7% (10/68) for SDS and 10.1% (7/69) for BDS, (P = .573). The costs per life-year saved were US$325,448, US$81,966, and US$3,670 at 180 days, one year and five years, respectively. BDS is not cost-sparing but is cost-effective if a survival benefit is maintained over several years. An individualized institutional approach to diagnostic strategies may maximize utility and cost-effectiveness.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

Molecular Imaging of Invasive Pulmonary Aspergillosis Using ImmunoPET/MRI: The Future Looks Bright

Invasive pulmonary aspergillosis (IPA) is a life-threatening lung disease of immuno-compromised humans caused by the ubiquitous environmental mold Aspergillus. Biomarker tests for the disease lack sensitivity and specificity, and culture of the fungus from invasive lung biopsy is slow, insensitive, and undesirable in critically ill patients. A computed tomogram (CT) of the chest offers a simple non-intrusive diagnostic procedure for rapid decision making, and so is used in many hematology units to drive antifungal treatment. However, radiological indicators that raise the suspicion of IPA are either transient signs in the early stages of the disease or not specific for Aspergillus infection, with other angio-invasive molds or bacterial pathogens producing comparable radiological manifestations in a chest CT. Improvements to the specificity of radiographic imaging of IPA have been attempted by coupling CT and positron emission tomography (PET) with [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG), a marker of metabolic activity well suited to cancer imaging, but with limited use in invasive fungal disease diagnostics due to its inability to differentiate between infectious etiologies, cancer, and inflammation. Bioluminescence imaging using single genetically modified strains of Aspergillus fumigatus has enabled in vivo monitoring of IPA in animal models of disease. For in vivo detection of Aspergillus lung infections in humans, radiolabeled Aspergillus-specific monoclonal antibodies, and iron siderophores, hold enormous potential for clinical diagnosis. This review examines the different experimental technologies used to image IPA, and recent advances in state-of-the-art molecular imaging of IPA using antibody-guided PET/magnetic resonance imaging (immunoPET/MRI).