Ontogeny of MAIT Cells in Neonates and Hematopoietic Stem Cell Transplant Recipients

Completed

• Conditions: Hematopoietic Stem Cell Transplant Recipient Children; Term and Preterm Neonates (24-41 Weeks Gestational Age)
• Interventions: Other: the rest of the blood test and stool sample; Other: Tubes fund recovery blood count

• Registration Number: NCT02403089
• Lead Sponsor: Assistance Publique - Hôpitaux de Paris

Brief Summary

The objective of this study is 1/ to determine the rate and kinetics of MAIT cell expansion and maturation in neonates in relation with gestational age, and in HSCT recipient children in relation with the source of donor stem cells, 2/ to correlate gut microbiota diversity and function with MAIT cell maturation and function in neonates and HSCT recipients; and 3/ to link MAIT cells and gut microbiota composition with microbial infections and severe intestinal inflammatory events in term and preterm neonates, and in HSCT recipients

Detailed Description

The mucosa-associated invariant T (MAIT) cells are innate-like T cells with restricted T cell receptor (TCR) usage, which are preferentially localized in mucosal tissues and respond to microbial infection by rapidly producing cytokines and cytotoxic effectors. They recognize the non-classical related molecule (MR1). MAIT cells react against a newly identified class of antigens presented by MR1: Riboflavin (Rib) precursors, which are found in most bacteria and yeasts. Currently, very little is known about the ontogeny of MAIT cells in the human, because of the difficulty to follow longitudinally their development. Cross-sectional studies have identified only the initial (cord blood) and final (adult subjects) steps of human MAIT cell maturation program. Moreover, there are no data on relationships between human MAIT cell expansion and maturation, and gut microbiota development. Given the potential importance of MAIT cells in protection from microbial infections at epithelial surfaces, we will investigate the maturation dynamics of MAIT cells in relation with gut microbiota diversity and function in two clinical settings characterized by a high predisposition to severe microbial infections before the establishment of protective adaptive immunity, namely i/ the neonatal period and ii/ the early immune reconstitution period following allogeneic hematopoietic stem cell transplantation (HSCT) in children. Our study will combine multiparametric phenotypic and functional characterization of MAIT cells with the use of new molecular microbiota analytic methodology (high throughput sequencing, metagenomics, Rib microbiology) to determine how the presence or functionality of MAIT cells is influenced by the gut microbiota.

Our consortium is composed of three independent research teams, experts in innate immunity, microbial ecology and MAIT cell biology, three independent clinical teams providing exceptional resources to patient samples, and one team providing expertise for methodology and statistical analysis. Their synergistic interaction will offer the various complementary expertise that is necessary for this project.

This project will decipher how MAIT cell numbers or functions are influenced by the gut microbiota composition, and reciprocally, how MAIT cells regulate or control expansion of gut microbiota components competing with opportunistic or pathogenic bacteria or responsible for infections. Ultimately, this study will determine how and when gut microbiota and MAIT cell interactions are involved in the control of severe infectious or intestinal inflammatory events in high risk infants, an indispensable step to design predictive biomarkers and ultimately propose new therapeutic options.

Study Timeline

• Study Start: 2015-03
• Study First Submitted: 2015-03-06
• Study First Submitted QC: 2015-03-25
• Study First Posted: 2015-03-31
• Status Verified: 2018-02
• Primary Completion: 2018-02
• Study Completion: 2018-02
• Last Update Submitted: 2023-02-02
• Last Update Posted: 2023-02-03

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 300

Inclusion Criteria

• neonates 24-41 weeks gestational age
• hematopoietic stem cell transplant recipient children (< 18 years old, donor source: cord blood or genoidentical donor)

Exclusion Criteria

• neonates : chromosomal abnormalities detected before birth
• source of HSCT: phenol-identical donors

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
children	the rest of the blood test and stool sample	hematopoietic stem cell transplant recipient children (\< 18 years old, donor source: cord blood or genoidentical donor)
neonates	Tubes fund recovery blood count	neonates 24-41 weeks gestational age

Primary Outcome Measures

Name	Time	Method
MAIT cell numbering neonates after birth	to 60days	Absolute number, percentage and phenotype of MAIT cells by flow cytometry in the circulating blood after birth according to gestational age and / or maternal-fetal infections (IMF), or after allogeneic HSCT according to the origin of HSCs.

Secondary Outcome Measures

Name	Time	Method
Absolute number of MAIT	to 60days	Absolute number and percentage of MAIT among mothers of infants on the day of delivery and in geno-identical donors before transplantation.
Absolute number of other immune cell populations	to 60 days	Absolute number and percentage of other immune cell populations by flow cytometry on the same blood samples.

Trial Locations

Locations (1)

Hôpital Robert Debré; 🇫🇷 Paris, France