Abstract

Allergen-specific T-cell priming

Postnatal maturation of T-cell immunity

Cross-sectional studies

Genetic basis for atopic risk

Prospective studies

Discussion
Board

Recent studies on the aetiology of allergy indicate that immunological processes which occur during very early life may determine the nature of an individual's allergen responder phenotype in adulthood. In particular, the programming of persistent allergen-specific Th2-polarised immunological memory which eventually leads to the expression of full blown allergic disease may frequently be complete by the end of infancy, or by the commencement of primary school. The key observations relevant to this process which are reviewed below include: (i) allergen specific T-cell priming to common environmental allergens occurs transplacentally in most subjects during late gestation and displays an overt Th2 polarity; (ii) following birth, Th2 polarised responses to food allergens are usually rapidly downregulated (anergy and/or deletion?), whereas those to inhalants are in the majority of cases immune deviated towards the Th1 cytokine phenotype; in infants with the atopic genotype, this immune deviation process occasionally fails, leading instead to the progressive amplification of Th2 responses against the inhalant allergens; (iii) infants with the atopic genotype display a transient maturational deficiency in Th1-associated function(s) during infancy, which appears to compromise their ability to immune deviate fetally-primed Th2 responses against inhalant allergens.

Back to the top.
Presentation Number SAholt0863
Keywords: atopy, perinatal, T cells, cytokines, immune deviation