Mononuclear cell reactivity to food allergens in neonates, children and adults.
A model of antigen-specific T-cell proliferative responses based on reciprocal patterns of responses to dietary and inhalant allergens has been suggested, the former being frequent in infancy but rare in adults, whereas the latter are preserved and expand between infancy and adulthood. We have evaluated the age-related variations of mononuclear cell reactivity to food allergens. The cord blood mononuclear cells (CBMC) of 30 neonates without family history of atopy and the peripheral blood mononuclear cells (PBMC) of 20 healthy children and of 40 healthy adults were stimulated in vitro with beta-lactoglobulin (BLG) or ovalbumin (OVA) and the cultures were harvested after 7 days. Neonates, children and adults were compared for the percentages of positive responses and for the magnitude of response. Adult subjects showed significantly lower percentages of positive responses and reduced magnitude of response than those observed in neonates and children either in BLG or in OVA cultures. We have not observed a decrease of food allergen mononuclear cell reactivity between neonates and children for the frequency of positive responses. The magnitude of response of neonates was significantly lower than that of children in BLG cultures. Our results seem to confirm the loss of mononuclear cell reactivity to food allergens in adult age. However, other reports show conflicting data. We suggest that a rigorous standardization of the methodological steps of in vitro mononuclear cell stimulation with allergen is necessary.