Immune function in rural Gambian children is not related to season of birth, birth size, or maternal supplementation status

Background: We previously showed that mortality from infectious diseases am ong young adults in rural Gambia is strongly correlated with the season of their birth. This suggests that early life insults that involve fetal malnu trition, exposure to natural toxins, or highly seasonal infections affectin g the infant or pregnant mother cause permanent damage to the immune system . Excess mortality begins after puberty and has a maximal odds ratio of > 1 0 for deaths between ages 25 and 50 y. Objective: We investigated the immune function of children according to bir th weight, season of birth, and exposure to maternal dietary supplementatio n during pregnancy. Design: Immune function was measured in 472 prepubertal children aged 6.5-9 .5 y from 28 villages in rural Gambia. The mothers of these children had be en randomly assigned to a high-energy prenatal supplementation program, whi ch significantly increased birth weight. This permitted supplementation sta tus, birth weight, and season of birth to be investigated as exposure varia bles. The outcome variables tested were naive responses to rabies and pneum ococcus vaccines, delayed-type hypersensitivity skin reactions, and mucosal defense (secretory immunoglobulin A and dual-sugar permeability). Results: Immune responses were strongly related to current age and sex, sug gesting a high level of sensitivity, but were not consistently related to b irth weight, season of birth, or maternal supplementation (control compared with intervention). Conclusion: Events in early life did not predict a measurable defect in imm une response within this cohort of rural Gambian children. It is possible t hat the early programming of immune function may be mediated through a defe ct in immunologic memory or early senescence rather than through impairment of early responses.