Study of Innate Host Immune Response to C. Glabrata Clinical Isolates Resistant to Echinocandins: Impact on the Management of Candidemia in High-risk Patients

Study Overview
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Brief Summary
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In the context of Candida yeast infections, a large number of studies have been published over the past two decades specifying the molecular mechanisms of antifungal resistance in different Candida species. However, few of these studies have explored how these mechanisms influence host immune response to this opportunistic pathogen. Recent advances in understanding how the host's immune system responds to Candida have initiated the emergence of a new research theme aimed at better understanding Candida's intrinsic and adaptive resistance mechanisms to antifungals can modulate escape to or recognition by the host's immune system. This knowledge could lead to (i) a better understanding of the predominance of certain Candida species with antifungal resistance in certain patient populations, (ii) a better understanding of why high levels of in vitro resistance are not necessarily correlated with in vivo therapeutic failure, and (iii) effective immunotherapeutic strategies to control Candida resistance to antifungals. It is therefore crucial to investigate the impact of Candida's resistance to antifungals on the host's innate immune response. Indeed, most antifungal resistance mechanisms have a direct or indirect structural modification of the fungal wall. However, it is the composition of this wall that is involved in the recognition of Candida by the host cell via the pattern recognition receptors (PRRs). We therefore put forward the very probable hypothesis that changes in the fungal wall, induced by the appearance of resistance, could alter the recognition of Candida by PRRs and thus trigger a different immune response, either qualitatively (type of cytokines secreted) or quantitatively (amplitude and duration of the immune response). However, even if initial experimental data support the hypothesis of a possible link between resistance and a modulation of the innate immune response in digestive mucosa (the most frequent starting point for disseminated candidiasis), many questions remain regarding (i) the proteins and mechanisms of the modulated immune cascade, (ii) the modification of the immune response according to the Candida species in question and (iii) the modification of the immune response according to the resistance phenotype in question.

Official Title
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Study of Innate Host Immune Response to C. Glabrata Clinical Isolates Resistant to Echinocandins: Impact on the Management of Candidemia in High-risk Patients

Conditions
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Candidemia of C. Glabrata

Intervention / Treatment
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* Other: in vitro evaluation of epithelial immune response during C. glabrata infection
* Other: study of the impact of resistance phenotype acquisition on the virulence of C. glabrata isolates


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 10 clinical isolates sensitive to all antifungal agents 10 echinocandin-resistant clinical isolates (Eucast, caspofungin > 8µg/ml) Clinical strains of C. glabrata susceptible or resistant to echinocandins will be selected on selected criteria: patient's immune status therapeutic management clinical developments Exclusion Criteria: Not applicable
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Reference strain ATCC<br>1 strain sensitive to all antifungals | Other: in vitro evaluation of epithelial immune response during C. glabrata infection<br>* study of the expression of genes coding for different proteins involved in the RTqPCR activation cascade study of protein expression by the Western-Blot method<br>Other: study of the impact of resistance phenotype acquisition on the virulence of C. glabrata isolates<br>* in vitro evaluation by measuring cell invasion, cell adhesion and by determining epithelial cell cytotoxicity. in vivo evaluation measured by a survival study on a CD-1 mouse model.<br>|
| Clinical isolates sensitive to all antifungal agents<br>10 clinical isolates sensitive to all | Other: in vitro evaluation of epithelial immune response during C. glabrata infection<br>* study of the expression of genes coding for different proteins involved in the RTqPCR activation cascade study of protein expression by the Western-Blot method<br>Other: study of the impact of resistance phenotype acquisition on the virulence of C. glabrata isolates<br>* in vitro evaluation by measuring cell invasion, cell adhesion and by determining epithelial cell cytotoxicity. in vivo evaluation measured by a survival study on a CD-1 mouse model.<br>|
| Echinocandin-resistant clinical isolates<br>10 echinocandin-resistant clinical isolates (Eucast, Caspofungin > 8µg/ml) | Other: in vitro evaluation of epithelial immune response during C. glabrata infection<br>* study of the expression of genes coding for different proteins involved in the RTqPCR activation cascade study of protein expression by the Western-Blot method<br>Other: study of the impact of resistance phenotype acquisition on the virulence of C. glabrata isolates<br>* in vitro evaluation by measuring cell invasion, cell adhesion and by determining epithelial cell cytotoxicity. in vivo evaluation measured by a survival study on a CD-1 mouse model.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quantification of accession and invasion | In vitro study of different virulence markers | Baseline | 
| Test SytoxOrange | In vitro study of different cytotoxicity markers in digestive epithelial cells | Baseline | 
| Quantification of the gene expression of the various cytokines associated with the immune response in digestive epithelial cells. |  | Baseline |