PRENATAL ALLERGEN CONTACT WITH MILK-PROTEINS

Background Cellular proliferation to various allergens (Dermatophagoid es pteronyssinus, beta-lactoglobulin, bovine serum albumin, ovalbumin) has been found in cord blood cells. Whether this reflects a sensitiza tion during foetal life is uncertain. Objective We studied the cellula r reactivity and cytokine production of cord blood cells in response t o cow's milk proteins in a randomly selected group of newborns. The de lineation of possible in utero allergen contact was attempted.Methods Cord blood mononuclear cells from 39 neonates were incubated with cow' s milk proteins (alpha-lactalbumin, beta-lactoglobulin, casein, alpha- casein, beta-casein, kappa-casein, bovine serum albumin) for 7 days, a nd proliferation was assessed by incorporation of [H-3]thymidine. Cord blood cell-derived interferon-gamma (IFN gamma) and interleukin-4 (IL -4) secretion was evaluated in response to allergen or phytohaemagglut inin (PHA) stimulation. Results A pronounced proliferation of cells st imulated with alpha-lactalbumin (ALA; mean stimulation index 8.0, 95% confidence interval 5.2-10.8), beta-lactoglobulin (BLG; mean stimulati on index 5.9, 95% confidence interval 3.2-8.6) and alpha-casein (2.6, 95% confidence interval 2.9-9.1), as opposed to unstimulated cells in medium, was found. No correlation was found between cellular prolifera tion to milk proteins and parental atopy, maternal total IgE or cord b lood IgE. IFN gamma production (but not IL-4) was inducible by PHA (ra nge 429-1810 pg/ml), but only in one individual upon stimulation with BLG. Preferentially, reduced IFN gamma levels were found in individual s with positive parental allergic history. Conclusion The recognition of allergen by cord blood cells indicates that allergen priming must o ccur prenatally. The relevance for subsequent sensitization is unclear .