Innate Immunity Gene Polymorphisms and Yeast Colonization

University Hospital, Lille2,200 enrolled

Overview

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).

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.

Study Type

OBSERVATIONAL

Enrollment

2,200

Conditions

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

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

Locations (6)

CHRU de Lille

Lille, Nord, France

Centre hospitalier

Arras, France

Centre hosptialier

Boulogne-sur-Mer, France

CH Schaffner

Lens, France

Hôpital Saint-Philibert

Lomme, France

CH Victor Provo

Roubaix, France

Outcomes

Primary Outcomes

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).

Time frame: From date of inclusion until the last day hospital stay (at once a week)

Secondary Outcomes

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

Time frame: 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 1. mouth (oropharyngeal swab) 2. stomach (gastric aspiration) 3. trachea (tracheal suctioning) 4. urine 5. rectum (rectal swab or stool).

Time frame: 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.

Time frame: at admission and weekly for at least two weeks after.