Innate Immunity Gene Polymorphisms and Yeast Colonization

Study Overview
=================
Brief Summary
-----------------
It is proposed to carry out the study in three medical or surgical intensive care units (ICU) in the CHRU, Lille, and the CHU, Besançon. In all patients admitted to these ICU (see Figure 2), a corrected index of colonisation (CIC) will be determined and blood samples will be taken for genotyping of the lectins MBL, Dectin-1 and Galectin-3 and for serology. Over the duration of hospitalisation (on average 28 days) and weekly, fungal colonisation will be assessed in all patients (according to the CIC), and antibodies to yeast glycans will be determined by a simultaneous multiparametric analysis involving several families of natural or synthetic antigens, and the detection of circulating antigens (mannan and β-1,3 glucan).

Detailed Description
-----------------
Determination of the CIC: The CIC will be determined on admission and then once a week during hospitalisation. This will be carried out on a fixed day for all patients; we will avoid determining the CIC any closer than 2 days apart. It is not planned in this study to modify the therapeutic strategy of the ICU services. The strains isolated will be stored in glycerol solution at -80°C. The specimens for genetic and serological analysis will be stored centrally in a local mycology laboratory. Genotyping of lectin genes and TLRs: Two tubes containing 6 ml of blood in EDTA will be taken from each patient for extraction of DNA Serological study, detection of antibodies to yeast glycans: 10 ml of whole blood will be taken from each patient on the day of inclusion and over the duration of hospitalisation (maximum total quantity of 40 ml). This will be done on a fixed day for all patients; we will avoid sampling any closer than 2 days apart. Functional tests on peripheral blood mononuclear cells (PBMCs) Taking into account the fact that the results of genotyping will not be available in real time and the need to work with freshly collected cells, a group size of 50 patients in group 2 (negative CIC over the duration of hospitalisation) and 50 patients in group 3 (negative CIC at admission but positive at hospital discharge) will be analysed. Stimulation tests will be carried out in the presence of whole yeasts or yeast extracts on sub-populations of cells isolated from 20 ml of peripheral blood in EDTA.

Official Title
-----------------
Analysis of TLRs and Lectin Gene Polymorphisms. Impact on Yeast Colonization in Hospitalized Patients and on Adaptive Response Against Yeast Glycans

Conditions
-----------------
Critical Illness

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Male or female patients, ≥18 years of age, admitted to medical or surgical ICU for a duration of >48 h, irrespective of their colonisation status. Exclusion Criteria: -Patient (or their representative) who refuses to participate in the study or to undergo the procedures required for the investigations (mycological sampling in order to determine the CIC, blood sampling for genotyping of DNA and for serology) Previous antifungal treatment (in the 15 days preceding admission to the ICU). A CIC value based on an insufficient number of sampled sites (<6). Neutropenic patients Patients who are receiving immunosuppressants (transplanted, grafted...) Patients who do not have universal cover or Social Security cover

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Group 1<br>Patients with candidemia | |
| Group 2<br>Patients without colonization during follow up | |
| Group 3<br>Patients without colonization at admission, with subsequent colonization during hospitalization | |
| Group<br>Patients colonized at admission, and during the whole hospitalization | |
| Group 5<br>Patients who develop colonization during hospitalization and become negative at discharge | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency of polymorphisms | the frequency is measured for the association between the presence of a polymorphism and colonization by Candida sp. frequency of polymorphisms at least one lectin gene or TLRs between some colonized patients (G5) and the non-colonized patients (G2). | From date of inclusion until the last day hospital stay (at once a week) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Genotyping of lectin genes and toll-like-receptors (TLRs) | The analysis relates to genetic factors already described for lectins and will also include variants of genes involved in innate immunity host-microorganism interactions such as TLRs | From date of inclusion until the last day hospital stay (at once a week) | 
| Colonization index | This index is calculated for each patient at the entrance of the service and then once a week until discharge (at least two weeks after admission). This index is the ratio between the number of body sites colonized heavily on the number of body sites explored when at least one colony of Candida spp. was observed. The determination of Candida colonization index requires the implementation of several samples from different body sites. The sampled anatomical sites concern mouth (oropharyngeal swab) stomach (gastric aspiration) trachea (tracheal suctioning) urine rectum (rectal swab or stool). | at admission and weekly for at least two weeks after. | 
| Functional tests on peripheral blood mononuclear cells (PBMC) | Functional tests on peripheral blood mononuclear cells (PBMC) obtained from mutated patients for given Innate-immunity genes will be carried out through stimulation tests in the presence of whole yeast or derived-molecules on isolated cell subpopulations. | at admission and weekly for at least two weeks after. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
genetic susceptibility, candida infection, colonization