Patogenia de la infección fúngica invasora

Risk Factors and Environmental Preventive Actions for Aspergillosis in Patients with Hematological Malignancies

(1) Background: Aspergillus spp. is a widely distributed filamentous fungus in the environment due to its high sporulation capacity. Currently, invasive aspergillosis (IA) is the most common invasive fungal infection in patients with hematologic malignancies, with high rates of mortality and morbidity. The multifactorial nature of the disease requires appropriate risk stratification to enable the most appropriate preventive measures to be adapted and implemented according to the characteristics of the patient. In this sense, the present research aims to identify recent risk factors and environmental control measures against invasive aspergillosis to establish preventive actions to reduce the incidence of invasive aspergillosis in hospitals. (2) Methods: We conducted a qualitative systematic review of the scientific literature on environmental risk factors and preventive measures for invasive aspergillosis in patients with hematologic malignancies. The Medline, Cochrane, and Scopus databases were consulted, following the PRISMA and STROBE guidelines. (3) Results: Adequate implementation of environmental control measures is presented as the most efficient intervention in terms of prevention to decrease the incidence of invasive aspergillosis in hospitals. Neutropenia, fungal contamination, insufficient environmental control measures in hospital and home settings, length of hospital stay, and anemia, are identified as independent risk factors. We show that HEPA, LAF, and Plasmair® systems are suitable methods to reduce the concentration of airborne fungal spores. Antifungal prophylaxis did not significantly influence IA reduction in our study. (4) Conclusions: Proper professional training and environmental control measures in hospitals are essential for the prevention of invasive aspergillosis. We should optimize risk stratification for patients with hematologic malignancies. Antifungal prophylaxis should be complementary to environmental control measures and should never be substituted for the latter. Studies should also be undertaken to evaluate the efficiency of environmental control measures against IA at patients' homes.

Cytokine response as a biomarker for early diagnosis and outcome prediction of stem cell transplant recipients and acute leukemia patients with invasive aspergillosis

We aimed to determine the role of serum cytokine expression in invasive aspergillosis (IA) diagnosis and outcome prediction in hematologic patients. In this multicenter study, serum cytokines (IL6, IL10, INF-gamma, IL12, IL4, TNF-alpha, IL17 and IL23) were prospectively recruited from all consecutive patients with hematologic malignances at IA diagnosis and compared to control patients matched by center, age, baseline disease and therapeutic regimen. We included 36 patients with IA and 36 controls. Serum levels of IL6 and IL10 cytokines on day 0 were significantly increased in patients with IA when compared to controls (p = 0.001 and p = 0.025, respectively), even in those who were neutropenic. No differences were observed for the other cytokines. IL6 and IL10 predicted IA with an area under the ROC curve of 0.74 (95% CI 0.62-0.86) and 0.64 (95% CI 0.51-0.77), respectively. The best cut-off point in predicting IA was 20.85 pg/mL for IL6 (sensitivity 72.2%; specificity 77.8%; PPV 76.5% and NPV 73.7%), and 0.045 pg/mL for IL10 (sensitivity 62.9%; specificity 63.9%; PPV 62.9% and NPV 63.9%). IL6 levels were associated with increased mortality, with the best cut-off value being 65.59 pg/mL in mortality prediction. In conclusion, in addition to current tests in place, IL6 and IL10 levels-as measured in plasma-may help clinicians diagnose IA. High levels of IL6 at IA diagnosis are related with worse outcomes.

Candida bloodstream infection in patients with systemic autoimmune diseases

OBJECTIVES

To describe the epidemiological, clinical and microbiological characteristics and mortality of patients with Candida bloodstream infection and systemic autoimmune diseases.

METHODS

We performed a retrospective multicenter study of candidemia in adults with systemic autoimmune diseases between 2010 and 2016.

RESULTS

Among 1040 patients with candidemia, 36 (3.5%) had a systemic autoimmune disease. The most common systemic autoimmune disease was rheumatoid arthritis (27.8%). The most common species was Candida albicans (66.7%). Twenty-two (61.1%) patients received a corticosteroid therapy and nine (25%) received an immunosuppressive therapy at the time of candidemia. The mortality rate was 27.8%.

CONCLUSIONS

Systemic autoimmune diseases are not common in patients with candidemia. The unadjusted mortality rate was comparable to other candidemia studies in the general population.

Aspergillus niger bloodstream infection in gastric cancer after common hepatic artery embolization: A case report

The present case study reported on a 62-year-old male patient with gastric cancer-associated Aspergillus (A.) niger bloodstream infection. The patient presented with massive hemorrhage in the gastrointestinal tract 3 months after total gastrectomy for gastric cancer. Conservative treatment consisting of blood transfusion to supplement blood volume loss was ineffective. Digital subtraction angiography indicated gastroduodenal artery bleeding. The first attempt of performing arterial embolization using gelatin sponges failed, while the second attempt of performing common hepatic artery embolization using gelatin sponges and micro-coil springs stopped the bleeding. Four weeks after angiography, the patient presented with the complication of A. niger bloodstream infection, which was cured using intravenous and oral voriconazole. Clinicians should be aware of the possibility of A. niger bloodstream infection after invasive operations in immunocompromised patients and apply timely antifungal treatment.

[Immunopathogenesis of invasive mould infections]

Invasive fungal infections caused by filamentous fungi are devastating diseases that occur in patients with a variety of immunosuppressive conditions. This review focuses on the pathogenesis of the most important invasive mycosis in the human being caused by the filamentous fungi Aspergillus, Fusarium, Scedosporium and mucorales. The first contact between the mould and the patient, the host defense to different fungi, including the role of mucosa in the innate immune system, the whole innate immune recognition receptors, and the pathways connecting innate and adaptive immunity, as well as the virulence factors of fungi, are discussed in this paper.

The role of IL-33 in host response to Candida albicans

BACKGROUND

Interleukin (IL) 33 is a recently identified pleiotropic cytokine that influences the activity of multiple cell types and orchestrates complex innate and adaptive immune responses.

METHODS

We performed an extensive review of the literature published between 2005 and 2013 on IL-33 and related cytokines, their functions, and their regulation of the immune system following Candida albicans colonization. Our literature review included cross-references from retrieved articles and specific data from our own studies.

RESULTS

IL-33 (IL-1F11) is a recently identified member of the IL-1 family of cytokines. Accumulating evidence suggests a pivotal role of the IL-33/ST2 axis in host immune defense against fungal pathogens, including C. albicans. IL-33 induces a Th2-type inflammatory response and activates both innate and adaptive immunity. Studies in animal models have shown that Th2 inflammatory responses have a beneficial role in immunity against gastrointestinal and systemic infections by Candida spp.

CONCLUSIONS

This review summarizes the most important clinical studies and case reports describing the beneficial role of IL-33 in immunity and host defense mechanisms against pathogenic fungi. The finding that the IL-33/ST2 axis is involved in therapeutic target has implications for the prevention and treatment of inflammatory diseases, including acute or chronic candidiasis.