Prevalence and serological diagnosis of relapse in paracoccidioidomycosis patients

Standardization of Semi-Quantitative Dot Blotting Assay-Application in the Diagnosis, Follow-Up, and Relapse of Paracoccidioidomycosis

INTRODUCTION

This study standardized a semi-quantitative dot blotting assay (DB) and a quantitative real-time polymerase chain reaction (qPCR) to detect specific antibodies for Paracoccidioides brasiliensis and its DNA in PCM patients.

METHODOLOGY

We evaluated 42 confirmed PCM patients upon admission using a serological double agar gel immunodiffusion test (DID), DB, and molecular tests (qPCR in total blood). The control groups included 42 healthy individuals and 37 patients with other infectious diseases. The serological progress during treatment was evaluated in eight patients, and there was a relapse diagnosis in ten patients using the Pb B.339 strain antigen. The cut-off points for the serological tests were determined by a receiver operator characteristic curve.

RESULTS

The DB and DID tests showed similar accuracy, but the DB identified lower antibody concentrations. Cross-reactions were absent in the DB assay. In the relapse diagnoses, DB exhibited much higher sensitivity (90%) than DID (30%).

CONCLUSIONS

A DB assay is easier and faster than a DID test to be performed; DB and DID tests show the same accuracy, while blood qPCR is not recommended in the diagnosis at the time of admission; cross-reactions were not observed with other systemic diseases; DB and DID tests are useful for treatment monitoring PCM patients; and a DB assay is the choice for diagnosing relapse. These findings support the introduction of semi-quantitative DB assays in clinical laboratories.

Diagnosis and Treatment of Pulmonary Coccidioidomycosis and Paracoccidioidomycosis

Coccidioidomycosis (CM) and paracoccidioidomycosis (PCM) are systemic mycoses that are highly endemic in Latin America and have recently been included on the World Health Organization (WHO) Fungal Priority Pathogens List. Coccidioides immitis and Coccidioides posadasii are recognized as etiological agents of CM, with peculiarities in their geographic distribution. The genus Paracoccidioides now includes Paracoccidioides lutzii and the Paracoccidioides brasiliensis complex, which encompasses four phylogenetic species. In both diseases, pulmonary signs and symptoms are the main reasons for patients to seek medical assistance, and they are frequently misdiagnosed as tuberculosis. In this paper, we present a critical view of the strategies for diagnosis and clinical management of CM and PCM. Over the past few decades, there has been an increase in the number of reports of endemic fungal infections in areas previously thought to be "non-endemic" due to climate change and increased travel, among other factors. Learning to recognize their main epidemiological aspects and clinical manifestations is crucial so that clinicians can include them in the differential diagnosis of lung disease and avoid late diagnosis.

Paracoccidioidomycosis: Current Status and Future Trends

Paracoccidioidomycosis (PCM), initially reported in 1908 in the city of São Paulo, Brazil, by Adolpho Lutz, is primarily a systemic and neglected tropical mycosis that may affect individuals with certain risk factors around Latin America, especially Brazil. Paracoccidioides brasiliensis sensu stricto, a classical thermodimorphic fungus associated with PCM, was long considered to represent a monotypic taxon. However, advances in molecular taxonomy revealed several cryptic species, including Paracoccidioides americana, P. restrepiensis, P. venezuelensis, and P. lutzii, that show a preference for skin and mucous membranes, lymph nodes, and respiratory organs but can also affect many other organs. The classical diagnosis of PCM benefits from direct microscopy culture-based, biochemical, and immunological assays in a general microbiology laboratory practice providing a generic identification of the agents. However, molecular assays should be employed to identify Paracoccidioides isolates to the species level, data that would be complemented by epidemiological investigations. From a clinical perspective, all probable and confirmed cases should be treated. The choice of treatment and its duration must be considered, along with the affected organs, process severity, history of previous treatment failure, possibility of administering oral medication, associated diseases, pregnancy, and patient compliance with the proposed treatment regimen. Nevertheless, even after appropriate treatment, there may be relapses, which generally occur 5 years after the apparent cure following treatment, and also, the mycosis may be confused with other diseases. This review provides a comprehensive and critical overview of the immunopathology, laboratory diagnosis, clinical aspects, and current treatment of PCM, highlighting current issues in the identification, treatment, and patient follow-up in light of recent Paracoccidioides species taxonomic developments.

Invasive Fungal Diseases in Africa: A Critical Literature Review

Invasive fungal diseases (IFDs) are of huge concern in resource-limited settings, particularly in Africa, due to the unavailability of diagnostic armamentarium for IFDs, thus making definitive diagnosis challenging. IFDs have non-specific systemic manifestations overlapping with more frequent illnesses, such as tuberculosis, HIV, and HIV-related opportunistic infections and malignancies. Consequently, IFDs are often undiagnosed or misdiagnosed. We critically reviewed the available literature on IFDs in Africa to provide a better understanding of their epidemiology, disease burden to guide future research and interventions. Cryptococcosis is the most encountered IFD in Africa, accounting for most of the HIV-related deaths in sub-Saharan Africa. Invasive aspergillosis, though somewhat underdiagnosed and/or misdiagnosed as tuberculosis, is increasingly being reported with a similar predilection towards people living with HIV. More cases of histoplasmosis are also being reported with recent epidemiological studies, particularly from Western Africa, showing high prevalence rates amongst presumptive tuberculosis patients and patients living with HIV. The burden of pneumocystis pneumonia has reduced significantly probably due to increased uptake of anti-retroviral therapy among people living with HIV both in Africa, and globally. Mucormycosis, talaromycosis, emergomycosis, blastomycosis, and coccidiomycosis have also been reported but with very few studies from the literature. The emergence of resistance to most of the available antifungal drugs in Africa is yet of huge concern as reported in other regions. IFDs in Africa is much more common than it appears and contributes significantly to morbidity and mortality. Huge investment is needed to drive awareness and fungi related research especially in diagnostics and antifungal therapy.

Immunologic Diagnosis of Endemic Mycoses

The endemic mycoses blastomycosis, coccidioidomycosis, histoplasmosis, paracoccidioidomycosis, cryptococcosis, sporotrichosis, talaromycosis, adiaspiromycosis, and emergomycosis are mostly caused by geographically limited thermally dimorphic fungi (except for cryptococcosis), and their diagnoses can be challenging. Usual laboratory methods involved in endemic mycoses diagnosis include microscopic examination and culture of biological samples; however, serologic, histopathologic, and molecular techniques have been implemented in the last few years for the diagnosis of these mycoses since the recovery and identification of their etiologic agents is time-consuming and lacks in sensitivity. In this review, we focus on the immunologic diagnostic methods related to antibody and antigen detection since their evidence is presumptive diagnosis, and in some mycoses, such as cryptococcosis, it is definitive diagnosis.

Epidemiology of paracoccidioidomycosis in Venezuela: a retrospective study from 1954 to 2019

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic mycosis endemic to Latin America. Etiological agents are Paracoccidioides species that diverge phylogenetically throughout South America.

OBJECTIVES

This study aimed to document the epidemiology of PCM in Venezuela.

METHODS

We have performed a retrospective cross-sectional descriptive study in 31,081 clinical records of patients from two reference centres during 65 years (1954-2019).

FINDINGS

PCM diagnosis was confirmed in 745 patients. Chronic PCM was the most prevalent form (90.06% cases); 80.67% were male and the most affected age range was 41-60. Farming and construction were the most prevalent occupation and Miranda State had a higher prevalence. Lung and skin were the most affected organs, followed by oral manifestations. Direct examination, culture and serology showed a high sensibility, and no statistical difference was observed among the diagnostic tools. Out of 17 Paracoccidioides isolates genotyped from Venezuela, one was typed as Paracoccidioides americana and 16 as Paracoccidioides venezuelensis.

MAIN CONCLUSIONS

Clinical manifestations observed, information about the epidemiology and molecular profile is essential not only for diagnosis but also for understanding therapeutic responses to mycotic drugs and prognosis. Therefore, it is necessary to sequence all positive isolated strains in order to confirm the dominance of P. venezuelensis in Venezuela.

Serological diagnosis of paracoccidioidomycosis using a Paracoccidioides spp. comercial antigen and the counterimmunoelectrophoresis method

Purpose

In-house Paracoccidioides spp. antigens are commonly used in the serological diagnosis of paracoccidioidomycosis (PCM). The sensitivity and specificity of a commercial Paracoccidioides spp. antigen was assessed for PCM serological testing.

Method

Counterimmunoelectrophoresis and double immunodiffusion were used to evaluate the Paracoccidioides ID Antigen® reagent in sera from PCM cases and patients with other diseases.

Results

All active PCM sera (n=24) were reactive using counterimmunoelectrophoresis (sensitivity = 100%), including 11 cases of infection by P. brasiliensis sensu stricto and one by P. americana. Fifteen (88%) out of 17 sera from patients on treatment or cured were reactive, including one case of P. lutzii infection. One to three bands of antigen-antibody precipitate were observed on the agarose gel, with a predominance of two to three bands in the test with untreated PCM sera or at the beginning of antifungal therapy. All sera from patients with histoplasmosis (n=7), aspergillosis (n=5), and other diseases (n=27) tested negative (specificity = 100%). The overall sensitivity and specificity using the commercial antigen and double diffusion test were 75% and 100%, respectively.

Conclusion

The commercial antigen performed satisfactorily and may contribute to the dissemination of the use of serological tests for the PCM diagnosis.

Delayed Relapse of Paracoccidioidomycosis in the Central Nervous System: A Case Report

Paracoccidioidomycosis is a dimorphic fungal infection endemic in Latin America. We report a patient with a history of pulmonary paracoccidioidomycosis who presented with relapsed disease in the central nervous system 4 years after initial treatment. We review current treatment strategies for paracoccidioidomycosis and neuroparacoccidioidomycosis.

Re-drawing the Maps for Endemic Mycoses

Endemic mycoses such as histoplasmosis, coccidioidomycosis, blastomycosis, paracoccidioidomycosis, and talaromycosis are well-known causes of focal and systemic disease within specific geographic areas of known endemicity. However, over the past few decades, there have been increasingly frequent reports of infections due to endemic fungi in areas previously thought to be “non-endemic.” There are numerous potential reasons for this shift such as increased use of immune suppressive medications, improved diagnostic tests, increased disease recognition, and global factors such as migration, increased travel, and climate change. Regardless of the causes, it has become evident that our previous understanding of endemic regions for these fungal diseases needs to evolve. The epidemiology of the newly described Emergomyces is incomplete; our understanding of it continues to evolve. This review will focus on the evidence underlying the established areas of endemicity for these mycoses as well as new data and reports from medical literature that support the re-thinking these geographic boundaries. Updating the endemic fungi maps would inform clinical practice and global surveillance of these diseases.

Virulence factors of Paracoccidioides brasiliensis as therapeutic targets: a review

Paracoccidiodomycosis (PCM) is a systemic mycosis caused by the fungus Paracoccidioides brasiliensis and Paracoccidioides lutzii. The disease requires long and complicated treatment. The aim of this review is to address the fungal virulence factors that could be the target of the development of new drugs for PCM treatment. Virulence factors favoring the process of fungal infection and pathogenicity are considered as a microbial attribute associated with host susceptibility. P. brasiliensis has some known virulence factors which are 43 kDa glycoprotein (gp 43) which is an important fungal antigen, 70 kDa glycoprotein (gp 70), the carbohydrates constituting the fungal cell wall α-1,3, glucan and β-1,3-glucan, cell adhesion molecules and the presence of melanin pigments. The discovery and development of drugs that interact with these factors, such as inhibitors of β-1,3-glucan, reduced synthesis of gp 43, inhibitors of melanin production, is of great importance for the treatment of PCM. The study of virulence factors favors the understanding of pathogen-host relationships, aiming to evaluate the possibility of developing new therapeutic targets and mechanisms that these molecules play in the infectious process, favoring the design of a more specific treatment for this disease.

Treatment compliance of patients with paracoccidioidomycosis in Central-West Brazil

Objective:

To evaluate the treatment compliance of patients with paracoccidioidomycosis.

Methods:

We studied 188 patients with paracoccidioidomycosis admitted to a tertiary referral hospital in the Central-West Region of Brazil from 2000 to 2010, to assess their compliance to treatment. In order to be considered compliant, patients needed to present two established criteria: (1) receive medicines from the pharmacy, and (2) achieve a self-reported utilization of at least 80% of the dispensed antifungal compounds prescribed since their previous appointment.

Results:

Most patients were male (95.7%), had the chronic form of the disease (94.2%), and were treated with cotrimoxazole (86.2%). Only 44.6% of patients were treatment compliant. The highest loss to follow-up was observed in the first 4 months of treatment (p < 0.02). Treatment compliance was higher for patients with than for those without pulmonary involvement (OR: 2.986; 95%CI 1.351-6.599), and higher for patients with than without tuberculosis as co-morbidity (OR: 2.763; 95%CI 1.004-7.604).

Conclusions:

Compliance to paracoccidioidomycosis treatment was low, and the period with the highest loss to follow-up corresponds to the first four months. Pulmonary paracoccidioidal involvement or tuberculosis comorbidity predicts a higher compliance to paracoccidioidomycosis therapy.

Ceruloplasmin, transferrin and apolipoprotein A-II play important role in treatment's follow-up of paracoccidioidomycosis patients

Paracoccidioidomycosis (PCM) is a systemic disease caused by thermodymorphic fungi of the Paracoccidioides brasiliensis complex, (Paracoccidioides spp.). Patients with PCM reveal specific cellular immune impairment. Despite the effective treatment, quiescent fungi can lead to relapse, usually late, the serological diagnosis of which has been deficient. The present study was carried out with the objective of investigating a biomarker for the identification of PCM relapse and another molecule behaving as an immunological recovery biomarker; therefore, it may be used as a cure criterion. In the evolutionary analysis of the proteins identified in PCM patients, comparing those that presented with those that did not reveal relapse, 29 proteins were identified. The interactions observed between the proteins, using transferrin and haptoglobin, as the main binding protein, were strong with all the others. Patient follow-up suggests that cerulosplamin may be a marker of relapse and that transferrin and apolipoprotein A-II may contribute to the evaluation of the treatment efficacy and avoiding a premature decision.

Serological proteomic biomarkers to identify Paracoccidioides species and risk of relapse

The sensitivity of the double agar gel immunodiffusion test is about 90% in patients with untreated paracoccidioidomycosis (PCM), but it is much lower in cases of relapse. In addition, serum from patients with PCM caused by Paracoccidioides lutzii, frequent in the Midwest region of Brazil, do not react with the classical antigen obtained from Pb B-339. These findings showed the need for alternative diagnostic methods, such as biological markers through proteomics. The aim of this study was to identify biomarkers for the safe identification of PCM relapse and specific proteins that could distinguish infections caused by Paracoccidioides brasiliensis from those produced by Paracoccidioides lutzii. Proteomic analysis was performed in serum from 9 patients with PCM caused by P. brasiliensis, with and without relapse, from 4 patients with PCM produced by P. lutzii, and from 3 healthy controls. The comparative evaluation of the 29 identified plasma proteins suggested that the presence of the immunoglobulin (Ig) alpha-2 chain C region and the absence of Ig heavy chain V-III TIL indicate infection by P. lutzii. In addition, the absence of complement factor B protein might be a predictor of relapse. The evaluation of these proteins in a higher number of patients should be carried out in order to validate these findings.

Paracoccidioidomycosis: Current Perspectives from Brazil

BACKGROUND

This review article summarizes and updates the knowledge on paracoccidioidomycosis. P lutzii and the cryptic species of P. brasiliensis and their geographical distribution in Latin America, explaining the difficulties observed in the serological diagnosis.

OBJECTIVES

Emphasis has been placed on some genetic factors as predisposing condition for paracoccidioidomycosis. Veterinary aspects were focused, showing the wide distribution of infection among animals. The cell-mediated immunity was better characterized, incorporating the recent findings.

METHODS

Serological methods for diagnosis were also compared for their parameters of accuracy, including the analysis of relapse.

RESULTS

Clinical forms have been better classified in order to include the pictures less frequently observesiod.

CONCLUSION

Itraconazole and the trimethoprim-sulfamethoxazole combination was compared regarding efficacy, effectiveness and safety, demonstrating that azole should be the first choice in the treatment of paracoccidioidomycosis.

Therapeutic Response in Adult Patients with Nonsevere Chronic Paracoccidioidomycosis Treated with Sulfamethoxazole-Trimethoprim: A Retrospective Study

According to the Brazilian Consensus on Paracoccidioidomycosis (PCM), itraconazole is the drug of choice for treatment. However, the combination of sulfamethoxazole and trimethoprim (SMX-TMP) is most commonly used in clinical practice because of its higher availability in the public health services. The aims of this study were to evaluate the therapeutic response of patients with nonsevere chronic PCM to SMX-TMP and highlight the factors related to treatment failure. An adequate therapeutic response was defined as completely improved disease signs and symptoms after medication use for a minimum of 6 months, followed by normalized hematological and biochemical changes, radiological improvements, and negative mycological examination findings. Medical records were analyzed for 244 patients with nonsevere chronic PCM who were treated between 1998 and 2014. In total, 41.9% of the patients had PCM for ≥ 8 months. Seven (2.9%) patients were coinfected with human immunodeficiency virus (HIV). The median (25%, 75% percentiles) treatment duration was 21 (10, 25) months. Adequate treatment adherence was reported by 68.3% of patients. In addition, 73.6% of patients exhibited an adequate therapeutic response. The majority (82.6%) of patients who were treated with SMX-TMP for > 24 months displayed an adequate therapeutic response, and the frequency of adequate therapeutic response gradually decreased as the duration of treatment decreased. Treatment nonadherence (P < 0.001) and PCM-HIV coinfection (P = 0.019) were factors associated with therapeutic failure. The study results support the good efficacy of SMX-TMP. Attention should be given to PCM-HIV coinfection, emphasizing the concern of a higher risk of PCM therapeutic failure in these patients.

Voice disorders in residual paracoccidioidomycosis in upper airways and digestive tract

BACKGROUND

Paracoccidioidomycosis (PCM) is a systemic mycosis of acute and chronic evolution, caused by species belonging to the genus Paracoccidioides. It is considered the most prevalent systemic endemic mycosis in Latin America, with cases in the tropical and subtropical regions. Residual PCM refers to the fibrotic scar sequelae resulting from the disease treatment which, when associated with collagen accumulation, leads to functional and anatomic alterations in the organs.

AIMS

The aim of this study was to evaluate the vocal function of patients with residual PCM in upper airways and digestive tract.

METHODS

We performed a cross-sectional study in 2010 in a cohort of 21 patients with residual PCM in upper airways and digestive tract.

RESULTS

The average age was 49.48±9.1 years, and only two (9.5%) patients were female. The study was performed in the 1-113 month-period (median 27) after the end of drug treatment. Five (23.8%) patients had alterations in the larynx as a sequela of the disease. However, all patients had vocal changes in vocal auditory perceptual analysis by GRBASI scale. The computerized acoustic analysis using the software Vox Metria, showed that 11 patients (52.4%) presented alterations in jitter, 15 (71.4%) in shimmer, 8 (38.1%) in F0, 4 (19%) in glottal to noise excitation (GNE), 7 (33.3%) in the presence of noise and 12 (57.1%) in the presence of vibratory irregularity.

CONCLUSIONS

The great frequency of alterations in residual PCM suggests that the patients in such phase could benefit from a multidisciplinary treatment, offering them integral monitoring of the disease, including speech rehabilitation after the PCM is healed.

Standardization and validation of Dot-ELISA assay for Paracoccidioides brasiliensis antibody detection

Background

Paracoccidioidomycosis (PCM) is a neglected systemic mycosis caused by a dimorphic fungus of the Paracoccidioides genus. The standard diagnosis is based on isolation of the fungi in culture, and by microscopic visualization of characteristic multiple budding yeast cells in biological samples. However, in some situations, access to the site of injury prevents the collection of biological material. A variety of immuno-serological techniques has proven useful for allowing inferring diagnosis with a certain degree of certainty, thus optimizing time. The aim of this study was to standardize and validate the Dot-ELISA (DE) assay, comparing it with the serological standard, double immunodiffusion (DI).

Methods

In order to standardize the DE assay, 143 serum samples were used. Out of those, 23 were from apparently healthy patients, 77 were from patients with confirmed PCM and 43 were from patients with other lung infections (tuberculosis, aspergillosis and histoplasmosis). To validate the DE technique, 300 serum samples from patients with PCM clinical suspicion (probable and possible cases) were employed, and these results were compared with those of DI.

Results

The DE assay showed sensitivity of 91%, specificity of 95.4%, positive predictive value of 96%, negative predictive value of 98.2%, accuracy of 93%, and great precision (k = 0.93). In addition, the nitrocellulose membranes have proved to be viable for using at least 90 days after P. brasiliensis B-339 antigen sensitization.

Conclusion

Dot-ELISA method was found to be an extremely promising tool as serologic screening technique, because of its high sensitivity. Furthermore, Dot-ELISA shows the prospect of being transferred to laboratories of mycoserology including those with fewer resources or even to be used directly in the field. It has an excellent shelf life – membranes coated with antigen can be used for testing without changes in the pattern of reactivity among laboratories – and presents reliable values of sensitivity, specificity, predictive values, accuracy and a high correlation with the serological standard methodology. Based on the present findings, it possible to state that this technique constitutes a remarkable option to be used in routine diagnosis for public health centers.

Cyclopalladated Compound 7a Induces Apoptosis- and Autophagy-Like Mechanisms in Paracoccidioides and Is a Candidate for Paracoccidioidomycosis Treatment

Paracoccidioidomycosis (PCM), caused by Paracoccidioides species, is the main cause of death due to systemic mycoses in Brazil and other Latin American countries. Therapeutic options for PCM and other systemic mycoses are limited and time-consuming, and there are high rates of noncompliance, relapses, toxic side effects, and sequelae. Previous work has shown that the cyclopalladated 7a compound is effective in treating several kinds of cancer and parasitic Chagas disease without significant toxicity in animals. Here we show that cyclopalladated 7a inhibited the in vitro growth of Paracoccidioides lutzii Pb01 and P. brasiliensis isolates Pb18 (highly virulent), Pb2, Pb3, and Pb4 (less virulent) in a dose-response manner. Pb18 was the most resistant. Opportunistic Candida albicans and Cryptococcus neoformans were also sensitive. BALB/c mice showed significantly lighter lung fungal burdens when treated twice a day for 20 days with a low cyclopalladated 7a dose of 30 μg/ml/day for 30 days after intratracheal infection with Pb18. Electron microscopy images suggested that apoptosis- and autophagy-like mechanisms are involved in the fungal killing mechanism of cyclopalladated 7a. Pb18 yeast cells incubated with the 7a compound showed remarkable chromatin condensation, DNA degradation, superoxide anion production, and increased metacaspase activity suggestive of apoptosis. Autophagy-related killing mechanisms were suggested by increased autophagic vacuole numbers and acidification, as indicated by an increase in LysoTracker and monodansylcadaverine (MDC) staining in cyclopalladated 7a-treated Pb18 yeast cells. Considering that cyclopalladated 7a is highly tolerated in vivo and affects yeast fungal growth through general apoptosis- and autophagy-like mechanisms, it is a novel promising drug for the treatment of PCM and other mycoses.

Advances and challenges in paracoccidioidomycosis serology caused by Paracoccidioides species complex: an update

Understanding the possible methodologies for the rapid and inexpensive identification of fungal infections is essential for disease diagnosis, but there are some limitations. To help with this problem, serological methods that detect antigens or antibodies are widely used and are useful for the diagnosis of paracoccidioidomycosis (PCM) through the detection of gp43, which is the main antigen employed for the immunodiagnosis of this disease caused by Paracoccidioides brasiliensis. However, the use of gp43 has become restricted because it was recently found that this marker is not identified in the infections caused by Paracoccidioides lutzii. Therefore, it is necessary to identify new antigens in both species or antigens specific for P. lutzii to decrease the morbidity and/or mortality associated with PCM. This review provides a discussion of new diagnostic challenges after the recent discoveries regarding the taxonomy of the Paracoccidioides genus.

Opportunistic yeast pathogens: reservoirs, virulence mechanisms, and therapeutic strategies

Life-threatening invasive fungal infections are becoming increasingly common, at least in part due to the prevalence of medical interventions resulting in immunosuppression. Opportunistic fungal pathogens of humans exploit hosts that are immunocompromised, whether by immunosuppression or genetic predisposition, with infections originating from either commensal or environmental sources. Fungal pathogens are armed with an arsenal of traits that promote pathogenesis, including the ability to survive host physiological conditions and to switch between different morphological states. Despite the profound impact of fungal pathogens on human health worldwide, diagnostic strategies remain crude and treatment options are limited, with resistance to antifungal drugs on the rise. This review will focus on the global burden of fungal infections, the reservoirs of these pathogens, the traits of opportunistic yeast that lead to pathogenesis, host genetic susceptibilities, and the challenges that must be overcome to combat antifungal drug resistance and improve clinical outcome.

Low-level laser therapy to the mouse femur enhances the fungicidal response of neutrophils against Paracoccidioides brasiliensis

Neutrophils (PMN) play a central role in host defense against the neglected fungal infection paracoccidioidomycosis (PCM), which is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb). PCM is of major importance, especially in Latin America, and its treatment relies on the use of antifungal drugs. However, the course of treatment is lengthy, leading to side effects and even development of fungal resistance. The goal of the study was to use low-level laser therapy (LLLT) to stimulate PMN to fight Pb in vivo. Swiss mice with subcutaneous air pouches were inoculated with a virulent strain of Pb or fungal cell wall components (Zymosan), and then received LLLT (780 nm; 50 mW; 12.5 J/cm2; 30 seconds per point, giving a total energy of 0.5 J per point) on alternate days at two points on each hind leg. The aim was to reach the bone marrow in the femur with light. Non-irradiated animals were used as controls. The number and viability of the PMN that migrated to the inoculation site was assessed, as well as their ability to synthesize proteins, produce reactive oxygen species (ROS) and their fungicidal activity. The highly pure PMN populations obtained after 10 days of infection were also subsequently cultured in the presence of Pb for trials of protein production, evaluation of mitochondrial activity, ROS production and quantification of viable fungi growth. PMN from mice that received LLLT were more active metabolically, had higher fungicidal activity against Pb in vivo and also in vitro. The kinetics of neutrophil protein production also correlated with a more activated state. LLLT may be a safe and non-invasive approach to deal with PCM infection.

PCM triggers a typical granulomatous inflammatory reaction with PMN playing a major role; these inflammatory cells are crucial in the initial stages of PCM, participating in the innate immune reaction and also directing the acquired immune response in the later stages. In some PCM patients, these immune mechanisms are insufficient to eradicate the infection, and need to be boosted with antifungal drugs that have to be administered for long periods and can show serious side-effects. We aimed to develop a novel and safe way to activate PMN through low-level laser irradiation of the bone marrow in the mouse femoral medulla. LLLT increased PMN viability and activation, shown by a significantly greater production of protein and ROS, as well as a higher fungicidal capacity; PMN even retained their higher metabolic activity and fungicidal ability after a second exposure to the pathogenic fungus in vitro. This is the first time that LLLT has been shown to increase the immune response against a fungal infection, and could be a promising and safe technique to be used with antifungal drugs in PCM.