Persistent poor long-term prognosis of allogeneic hematopoietic stem cell transplant recipients surviving invasive aspergillosis

CD56-mediated activation of human natural killer cells is triggered by Aspergillus fumigatus galactosaminogalactan

Invasive aspergillosis causes significant morbidity and mortality in immunocompromised patients. Natural killer (NK) cells are pivotal for antifungal defense. Thus far, CD56 is the only known pathogen recognition receptor on NK cells triggering potent antifungal activity against Aspergillus fumigatus. However, the underlying cellular mechanisms and the fungal ligand of CD56 have remained unknown. Using purified cell wall components, biochemical treatments, and ger mutants with altered cell wall composition, we herein found that CD56 interacts with the A. fumigatus cell wall carbohydrate galactosaminogalactan (GAG). This interaction induced NK-cell activation, degranulation, and secretion of immune-enhancing chemokines and cytotoxic effectors. Supernatants from GAG-stimulated NK cells elicited antifungal activity and enhanced antifungal effector responses of polymorphonuclear cells. In conclusion, we identified A. fumigatus GAG as a ligand of CD56 on human primary NK cells, stimulating potent antifungal effector responses and activating other immune cells.

The Specific Binding and Promotion Effect of Azoles on Human Aldo-Keto Reductase 7A2

Human AKR 7A2 broadly participates in the metabolism of a number of exogenous and endogenous compounds. Azoles are a class of clinically widely used antifungal drugs, which are usually metabolized by CYP 3A4, CYP2C19, and CYP1A1, etc. in vivo. The azole-protein interactions that human AKR7A2 participates in remain unreported. In this study, we investigated the effect of the representative azoles (miconazole, econazole, ketoconazole, fluconazole, itraconazole, voriconazole, and posaconazole) on the catalysis of human AKR7A2. The steady-state kinetics study showed that the catalytic efficiency of AKR7A2 enhanced in a dose-dependent manner in the presence of posaconazole, miconazole, fluconazole, and itraconazole, while it had no change in the presence of econazole, ketoconazole, and voriconazole. Biacore assays demonstrated that all seven azoles were able to specifically bind to AKR7A2, among which itraconazole, posaconazole, and voriconazole showed the strongest binding. Blind docking predicted that all azoles were apt to preferentially bind at the entrance of the substrate cavity of AKR7A2. Flexible docking showed that posaconazole, located at the region, can efficiently lower the binding energy of the substrate 2-CBA in the cavity compared to the case of no posaconazole. This study demonstrates that human AKR7A2 can interact with some azole drugs, and it also reveals that the enzyme activity can be regulated by some small molecules. These findings will enable a better understanding of azole-protein interactions.

International Multicenter Experience in the Treatment Outcome of Invasive Aspergillosis in Immunocompromised Cancer Patients

Background

Invasive aspergillosis (IA) is a life-threatening infection in immunocompromised patients. In this study, we compared the efficacy of voriconazole containing regimen vs non-voriconazole containing regimen in patients with IA.

Methods

In this retrospective study, we reviewed the medical records of all immunocompromised cancer patients diagnosed with proven or probable IA between February 2012 and March 2018. This trial included 26 patients from the American University of Beirut, Lebanon, 20 patients from Hospital das Clinicas da Faculdade de Medicina, Universidade de São Paulo, Brazil, and 10 patients from St. Luke’s International Hospital Tokyo, Japan.

Results

A total of 56 patients were analyzed. They were divided into 2 groups voriconazole containing regimen and non-voriconazole containing regimen (90% Amphotericin B based regimen). Both groups had similar characteristic, age, gender, and immunocompromised status. The majority of patients had underlying leukemia (63%), followed by lymphoma (20%), myeloma (16%) and other hematologic malignancy (1%). Antifungal primary therapy with voriconazole-containing regimen was associated with better response to treatment (p = 0.003). Survival analysis showed that primary therapy with a voriconazole containing regimen was significantly associated with improved survival (p =0.006). By multivariate logistic regression analysis, mechanical ventilation was a predictor of worse outcomes (poor response to therapy and increased mortality within 6 months), whereas primary treatment with voriconazole containing regimen was associated with improved outcomes including response to primary therapy (OR=18.1, p=0.002) and 6-month mortality (OR=0.14, p=0.011).

Conclusions

Based on international experience in immunocompromised cancer patients with IA, primary therapy with voriconazole-containing regimen is associated with improved response and survival compared with non-voriconazole amphotericin B based regimen

CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells

Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.

A new time-dependent approach for assessment of the impact of invasive aspergillosis shows effect on short- but not on long-term survival of patients with AML or high-risk MDS

Invasive aspergillosis (IA) has been reported to yield high mortality rates. Patients with an unfavourable prognostic haematological disease not only have a higher probability of developing IA but are also more likely to die due to causes directly related to the underlying disease. This complexity of risk mechanisms confounds the causal interpretation of IA occurrence and mortality. Full consideration of the changing patient characteristics over time is necessary to obtain reliable estimates of the correlation of IA with mortality. We studied the effect of IA on mortality in 167 consecutive patients starting with remission-induction therapy for AML or of whom most patients continued to haematopoietic stem cell transplantation (HSCT). No standard antifungal prophylaxis was administered in the period before HSCT. Survival analyses were performed to determine risk estimates of IA for different phases of treatment before and after HSCT. Time-dependent adjustment for confounding variables was performed using Cox proportional hazards models. In 55 of 167 enroled patients, IA was diagnosed. Before HSCT, adjusted hazard ratios and 95% confidence intervals on mortality after the diagnosis of IA were 3.5 (1.7-7.5), 2.0 (0.69-5.9), 2.3 (0.79-6.8) and 0.80 (0.49-1.4) within 30 days, between 30 and 60 days, between 60 and 90 days or more than 90 days, respectively. A similar pattern was observed after HSCT. The occurrence of IA did not significantly influence the decision to follow through with HSCT. The results provide new insights in short- and long-term survival of patients diagnosed with IA. A significantly increased mortality risk was only observed in the first month after diagnosis of IA. No unfavourable association with mortality was observed in the later course of treatment. The occurrence of IA did not affect the probability of attaining HSCT in our population.

Fulminant Laryngeal-tracheobronchial-pulmonary Aspergillosis: A Rare and Fatal Complication in Allogeneic Hematopoietic Stem Cell Transplantation Recipients

A 23-year-old man who had previously undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT) for severe aplastic anemia was diagnosed with invasive laryngeal-tracheobronchial-pulmonary aspergillosis after presenting with a persistent dry cough at six months post-transplantation based on the findings of laryngoscopy and fiberoptic bronchoscopy. A fiberoptic bronchoscope was used to remove the obstructive material from the patient's airway and posaconazole plus caspofungin were administered to successfully to treat the patient. Our report suggests that laryngoscopy and fiberoptic bronchoscopy should be considered as alternative approaches to the diagnosis and treatment of allo-HSCT recipients with persistent respiratory symptoms when invasive laryngeal aspergillosis and invasive tracheobronchial aspergillosis are suspected.

The Changing Epidemiology of Invasive Fungal Infections

Invasive fungal infections (IFI) are an emerging problem worldwide with invasive candidiasis and candidemia responsible for the majority of cases. This is predominantly driven by the widespread adoption of aggressive immunosuppressive therapy among certain patient populations (e.g., chemotherapy, transplants) and the increasing use of invasive devices such as central venous catheters (CVCs). The use of new immune modifying drugs has also opened up an entirely new spectrum of patients at risk of IFIs. While the epidemiology of candida infections has changed in the last decade, with a gradual shift from C. albicans to non-albicans candida (NAC) strains which may be less susceptible to azoles, these changes vary between hospitals and regions depending on the type of population risk factors and antifungal use. In certain parts of the world, the incidence of IFI is strongly linked to the prevalence of other disease conditions and the ecological niche for the organism; for instance cryptococcal and pneumocystis infections are particularly common in areas with a high prevalence of HIV disease. Poorly controlled diabetes is a major risk factor for invasive mould infections. Environmental factors and trauma also play a unique role in the epidemiology of mould infections, with well-described hospital outbreaks linked to the use of contaminated instruments and devices. Blastomycosis is associated with occupational exposure (e.g., forest rangers) and recreational activities (e.g., camping and fishing).The true burden of IFI is probably an underestimate because of the absence of reliable diagnostics and lack of universal application. For example, the sensitivity of most blood culture systems for detecting candida is typically 50 %. The advent of new technology including molecular techniques such as 18S ribosomal RNA PCR and genome sequencing is leading to an improved understanding of the epidemiology of the less common mould and dimorphic fungal infections. Molecular techniques are also providing a platform for improved diagnosis and management of IFI.Many factors affect mortality in IFI, not least the underlying medical condition, choice of therapy, and the ability to achieve early source control. For instance, mortality due to pneumocystis pneumonia in HIV-seronegative individuals is now higher than in seropositive patients. Of significant concern is the progressive increase in resistance to azoles and echinocandins among candida isolates, which appears to worsen the already significant mortality associated with invasive candidiasis. Mortality with mould infections approaches 50 % in most studies and varies depending on the site, underlying disease and the use of antifungal agents such as echinocandins and voriconazole. Nevertheless, mortality for most IFIs has generally fallen with advances in medical technology, improved care of CVCs, improved diagnostics, and more effective preemptive therapy and prophylaxis.

Current Indications, Techniques, and Imaging Findings of Stem Cell Treatment and Bone Marrow Transplant

The role of stem cell therapy in the treatment of hematologic and nonhematologic conditions is ever increasing. A thorough knowledge of the applications of stem cells and transplant physiology is essential for understanding the imaging manifestations. Stem cell imaging includes molecular imaging, and diagnostic and interventional radiology. It is possible to make a diagnosis of various complications and diseases associated with stem cell transplant. This article presents a simplified overview of stem cell applications and techniques with focus on hematopoietic stem cell transplant imaging.

Invasive aspergillosis in neutropenic patients during hospital renovation: effectiveness of mechanical preventive measures in a prospective cohort of 438 patients

BACKGROUND

Aspergillus species are the main cause of invasive fungal disease for patients with severe and prolonged neutropenia. Building or renovation works have been shown as one of the major causes of outbreaks of aspergillosis.

OBJECTIVES

This study aimed to assess the effectiveness of introduction and adaptation by air sampling of mechanical preventive measures on the incidence of invasive pulmonary aspergillosis in neutropenic patients during hospital renovation.

PATIENTS

All of the patients admitted for prolonged and severe neutropenia during a renovation period from 2003 to 2008 were prospectively enrolled. Invasive pulmonary aspergillosis (IPA) cases were classified as possible, probable, and proven, according to the 2008 European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) Consensus Group criteria. The effectiveness of preventive measures was determined by air sampling.

RESULTS

We recorded 705 hospitalizations for neutropenia concerning 438 patients. The majority of hospitalized neutropenic patients was treated for acute leukemia (38.3 %), followed by patients suffering from non-Hodgkin and Hodgkin lymphomas (33 %). The total cumulative incidence of probable and proven IPA was 4.1 %. Risk factors for developing IPA were underlying disease, treatment course at the time of hospitalization, and the mean duration of hospitalization and of neutropenia.

CONCLUSIONS

In this prospective study, the incidence of invasive pulmonary aspergillosis did not increase in neutropenic patients during a renovation period because of efficient mechanical preventive measures systematically adjusted using the results of air sampling.

Invasive aspergillosis caused by Aspergillus terreus: an emerging opportunistic infection with poor outcome independent of azole therapy

OBJECTIVES

Invasive aspergillosis (IA) caused by Aspergillus terreus is a significant cause of morbidity and mortality in patients with haematological malignancy (HM). Very few data are available in this patient population to differentiate IA patients with A. terreus from those with non-terreus species of Aspergillus to compare outcomes. We retrospectively investigated 513 HM patients who were treated for either definite or probable IA between June 1993 and August 2012 in a cancer centre.

METHODS

We compared baseline characteristics, antifungal therapies and outcomes between patients infected with A. terreus (n = 96, 18.7%) and those infected with non-terreus Aspergillus species (n = 335, 65.3%). Eighty-one patients with mixed or unspecified Aspergillus infections were excluded.

RESULTS

Breakthrough infections occurred more frequently in the A. terreus group (91% versus 77%, P = 0.009). A. terreus infection was associated with a lower rate of final response to antifungal therapy (21% versus 38%, P = 0.0015) and a higher rate of IA-associated mortality (51% versus 30%, P < 0.001). Multivariate analyses showed that these associations were independent of patients' clinical characteristics and the antifungal regimens they received. Factors independently associated with final response included treatment with azoles (OR 3.1, 95% CI 1.9-5.0, P < 0.0001) and Aspergillus species (A. terreus versus non-terreus Aspergillus species) (OR 0.5, 95% CI 0.3-0.98, P = 0.043). Additionally, Aspergillus species and treatment with azoles were independently associated with IA-associated mortality.

CONCLUSIONS

A. terreus IA in HM patients was associated with worse outcome than IA caused by non-terreus Aspergillus species. Poor prognosis in patients with invasive A. terreus infections is independent of anti-Aspergillus azole-based treatment.

Fever-range temperature modulates activation and function of human dendritic cells stimulated with the pathogenic mould Aspergillus fumigatus

In immunocompromised patients, invasive aspergillosis (IA) is the most frequent disease caused by the pathogenic mould Aspergillus fumigatus. Fever is one of the most common yet nonspecific clinical symptoms of IA. To evaluate the role of hyperthermia in the innate immune response to A. fumigatus in vitro, human monocyte-derived dendritic cells (DCs) were stimulated with germ tubes of A. fumigatus or the fungal cell wall component zymosan at 37°C or 40°C, followed by characterization of specific DC functions. While maturation of DCs was enhanced and DC phagocytic capacity was reduced at 40°C, we observed that DC viability and cytokine release were unaffected. Thus, our results suggest that hyperthermia has substantial impacts on DC function in vitro, which might also influence the course and outcome of IA in immunocompromised patients.

An update on pulmonary complications of hematopoietic stem cell transplantation

The indications for hematopoietic stem cell transplantation (HSCT) continue to expand. However, the risk for pulmonary complications post-HSCT continues to be high. Early recognition and treatment of pulmonary complications may improve outcomes. This is an overview of diagnosis, manifestations, and treatment of the most common infectious and noninfectious pulmonary complications post-HSCT. Knowing the patient's timeframe post-HSCT (preengraftment, postengraftment, late), type of HSCT (allogeneic vs autologous), radiographic findings, and clinical presentation can help to differentiate between the many pulmonary complications. This article will also address pretransplantation evaluation and infectious and noninfectious complications in the patient post-HSCT. While mortality post-HSCT continues to improve, respiratory failure continues to be the leading cause of ICU admissions for patients who have undergone HSCT. Mechanical ventilation is a predictor of poor outcomes in these patients, and further research is needed regarding their critical care management, treatment options for noninfectious pulmonary complications, and mortality prediction models posttransplantation.

Role of management strategies in reducing mortality from invasive fungal disease in children with cancer or receiving hemopoietic stem cell transplant: a single center 30-year experience

BACKGROUND

In the last decades, several diagnostic and therapeutic strategies have been implemented for management of invasive fungal diseases (IFD) in patients with cancer or receiving allogeneic hemopoietic stem cell transplant. Few data are available on their impact on mortality in children.

METHODS

All IFD episodes diagnosed at tertiary care center during a 30-year period between 1983 and 2012 were analyzed for 90-day mortality and risk factors. Diagnoses were coded according to international (European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group) criteria. Four treatment eras (1983-1990, 1991-1999, 2000-2005 and 2006-2012) were defined according to availability of diagnostic technologies, new antifungal drugs and use of a diagnostic-driven approach without empiric antifungal therapy.

RESULTS

A total of 198 IFD were diagnosed in 191 patients; 71.2% were proven/probable infections; 39.9% were caused by yeasts and 31.3% by molds. Within 90 days from IFD diagnosis, 58 (30.4%) patients died for a 28.3% cumulative probability of death. A multivariable analysis showed that the highest risk of death was associated with alternative donor-hemopoietic stem cell transplant [hazard ratio (HR): 3.96] and mold etiology (HR: 1.34). The risk of death significantly decreased across the treatment eras, with almost a 3-fold reduced risk for patients diagnosed during the 2006-2012 period (HR: 0.24). Also if the variable year of diagnosis was considered as continuous, the hazard of death significantly decreased by 5% per year (HR: 0.95).

CONCLUSIONS

New management strategies resulted in a better prognosis of IFD in children with cancer or hemopoietic stem cell transplant. A diagnostic-driven approach was not associated with an increase in mortality.

Molecular methods for detection of invasive fungal infections and mycobacteria and their clinical significance in hematopoietic stem cell transplantation

Infection remains an important source of morbidity and mortality in patients who undergo hematopoietic stem cell transplantation (HSCT). In the immune reconstitution period after transplantation, HSCT recipients are most likely to have bacterial or fungal infections. Invasive fungal infections (IFIs) and mycobacterial infections (MBIs) are among the complications of HSCT, with high morbidity and mortality rates. Early diagnosis of both is crucial in order to manipulate the disease and to avoid fulminant outcomes. This chapter reviews the current knowledge on the molecular diagnosis of IFIs and MBIs in HSCT recipients, describing two different polymerase chain reaction (PCR)-based methods, one commercial (qPCR, Roche) and one in-house IS6110-based protocol.