Associations between the human immune system and gut microbiome with neurodevelopment in the first 5 years of life: A...

Area of Science:

• Neuroscience
• Immunology
• Microbiology
• Developmental Pediatrics

Background:

• The early life immune system and gut microbiome are increasingly recognized for their potential influence on brain development.
• Understanding these interactions is crucial for identifying early markers of neurodevelopmental trajectories.
• Current literature has not comprehensively mapped the available evidence on biomarker associations.

Purpose of the Study:

• To systematically review and map existing literature on maternal and infant immune and gut microbiome biomarkers.
• To assess their associations with child neurodevelopmental outcomes within the first five years of life.
• To identify gaps in the current research landscape.

Main Methods:

• A PRISMA-ScR compliant systematic review of peer-reviewed, English-language articles.
• Inclusion criteria focused on studies reporting immune or gut microbiome biomarkers and neurodevelopmental outcomes before age five.
• Data extraction and synthesis of findings from eligible studies.

Main Results:

• Sixty-nine studies were included out of 23,495 retrieved.
• Most studies focused on the infant immune system (40) or maternal immune system (18), with fewer on the infant gut microbiome (13).
• No studies examined the maternal microbiome, and very few integrated both immune and microbiome biomarkers or maternal and infant biomarkers; reported associations were largely nonsignificant with small effect sizes.

Conclusions:

• There is a significant gap in research examining the interplay between maternal/infant immune and gut microbiome biomarkers and early neurodevelopment.
• The heterogeneity in study designs and methodologies hinders consistent findings.
• Future research should adopt integrated, multi-system approaches to elucidate the biological underpinnings of early child development.