Impact of dietary aflatoxin on immune development in Gambian infants: a cohort study
Ya Xu1, Sophie Moore2, Gaoyun Chen3
1School of Medicine, University of Leeds, Leeds, UK.
Insights
Chronic aflatoxin exposure in infants may impair immune development. This study found a negative association between aflatoxin levels and thymic size, a key indicator of immune function in early life.
Area of Science:
- Pediatric immunology
- Toxicology
- Nutritional science
Background:
- Chronic aflatoxin (AF) exposure is prevalent in sub-Saharan African children, linked to growth and immune issues.
- Early infancy is a critical window for immune system development.
Purpose of the Study:
- To investigate the impact of AF exposure on infant immune development.
- Utilized thymic size and antibody response to vaccination as immune indicators.
Main Methods:
- 374 infants enrolled in a nutritional supplementation trial.
- Measured thymic index (TI) via sonography at multiple time points.
- Assessed antibody (Ab) responses to diphtheria-tetanus-pertussis (DTP) vaccine.
- Quantified AF-albumin (AF-alb) adducts as a biomarker of AF exposure.
Main Results:
- AF-albumin levels increased with infant age, with 98% detection by 52 weeks.
- Significant negative association between AF-albumin and thymic index in the first 24 weeks (p<0.001 at 8 weeks).
- No association with pertussis/tetanus antibody response, but a positive correlation with diphtheria antibody titre (p<0.005).
Conclusions:
- High aflatoxin exposure in early infancy may negatively impact immune system development.
- Thymic size is particularly sensitive to AF exposure during rapid growth periods.
Background:
Chronic aflatoxin (AF) exposure has been shown to occur at high levels in children from sub-Saharan Africa (SSA), and has been associated with growth retardation and immune dysfunction. Our objective was to investigate the impact of AF exposure on immune development in early infancy using thymic size and antibody (Ab) response to vaccination as indicators of immune function.
Methods:
A total of 374 infants born between May 2011 and December 2012 were enrolled into the current study. These infants were recruited from a larger, randomised trial examining the impact of nutritional supplementation of mothers and infants on infant immune development (the Early Nutrition and Immune Development Trial). Thymic size (Thymic Index, TI) was measured by sonography at 1 week, 8 weeks, 24 weeks and 52 weeks of infant age. Infants were given the diphtheria-tetanus-pertussis (DTP) vaccine at 8 weeks, 12 weeks and 16 weeks of age, and Ab responses to each vaccine measured at 12 weeks and 24 weeks of age. AF-albumin (AF-alb) adduct levels in infant blood were measured by ELISA as the biomarker of AF exposure.
Results:
The geometric mean (GM) level of AF-alb increased with age. Only half of infants had detectable AF-alb with a GM of 3.52 pg/mg at 24 weeks, increasing to 25.39 pg/mg at 52 weeks, when 98% of infants had AF-alb >limit of detection. Significant negative association of AF-alb level with TI was seen in infants during the first 24 weeks, especially at 8 weeks of age (p<0.001), which is the time point of fastest thymus growth. There were no associations between AF exposure level and Ab response to pertussis and tetanus, but a significant positive correlation was observed between AF-alb level and Ab titre to diphtheria (p<0.005).
Conclusions:
High levels of AF exposure during early infancy may impact on infant immune development.
Trial Registration Number:
ISRCTN49285450.
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