Adult onset of cow's milk protein allergy with small-intestinal mucosal IgE mast cells

Human basophil activation measured by CD63 expression and LTC4 release in IgE-mediated food allergy

BACKGROUND

IgE-dependent basophil activation induced by an allergen elicit the release of LTC4 and the expression of the CD63 membrane marker.

OBJECTIVE

The aim of this study was to check if flow cytometric analysis of basophil activation could be applied to food allergy diagnosis and if this method paralleled LTC4 release.

METHODS

Patients were selected by the clinical history, skin tests, and provocation tests. Basophil activation induced by food extracts was studied in 24 control subjects and in 27 patients having a food allergy by LTC4 release test (LRT) and by flow cytometric anti-IgE+, CD63 + cell counting (BAT = basophil activation test). In case of negative anti-IgE response a passive blood donor basophil passive sensitization step was added to LRT and BAT. Leucocyte histamine release test was performed in 11 patients.

RESULTS

Basophil activation test was positive in 18/31 cases and LRT in 22/34 cases for food-allergic patients and, respectively, in 1/33 and 1/35 cases for the controls. A correlation was observed between specific IgE, BAT, and LRT. Basophil activation test and LRT performed after passive sensitization had an excellent sensitivity only for specific IgE levels ranging between 3.5 and 35 KU/L.

CONCLUSION

The present study shows that allergen-induced LTC4 release and anti-IgE, antiCD63 bicolor flow cytometric analysis of basophil activation may be used for food allergy diagnosis. Both tests have a good sensitivity and specificity. Basophil activation test and LRT are more efficient than histamine release test in case of high spontaneous histamine release, frequently observed in case of food allergy.

Neither intact nor hydrolyzed soy proteins elicit intestinal inflammation in neonatal piglets

BACKGROUND

Efficacy of feeding hydrolyzed soy proteins to infants intolerant to cow milk proteins has not been determined fully. This study compared growth and intestinal responses of neonatal piglets fed formulas with hydrolyzed soy protein to piglets fed formulas with intact soy or cow milk (casein-whey) proteins.

METHODS

Piglets (n = 40, day 2 postpartum) were fed commercial milk replacer until day 7 postpartum (designated day 0) and then were assigned randomly to casein-whey (CW) or soy (intact, SI; hydrolyzed SH) formulas to evaluate intestinal responses on days 0, 2, 5, and 10.

RESULTS

Average daily gain was higher for CW (121 g/d; p < .05) compared with SI piglets 85 g/d); SH pig weight gain was intermediate (109 g/d). Villus height-to-crypt depth ratio in proximal jejunum was lower (p < .05) on day 2 than day 0 in soy-fed pigs and lower (p < .05) on day 5 than day 0 in CW pigs. Mucosal mast cells were generally higher in CW pigs compared with soy-fed pigs. Villus goblet cell numbers in the midjejunum of SH-fed piglets were lower (p < .05) on day 5 compared with day 0. On day 5, crypt goblet cell numbers were higher (p < .05) in the midjejunum of CW-fed piglets compared with SH-fed piglets with numbers intermediate for SI-fed piglets. Intestinal differences were not detected among dietary treatments for major histocompatibility complex class I and II gene expression, tissue concentrations of prostaglandin E2, or CD8+ T-cell numbers.

CONCLUSIONS

Hydrolyzed soy proteins do not elicit intestinal inflammatory responses in piglets and may be viable alternatives to milk and intact soy proteins for feeding infants.

Milk hypersensitivity--key to poorly defined gastrointestinal symptoms in adults

Lactose intolerance is a common adverse reaction to milk in adults, while milk hypersensitivity is a disorder of infancy. We hypothesized that milk hypersensitivity may cause many unspecific gastrointestinal disorders in adults. Twenty adults were subjected to double-blind, placebo-controlled milk challenge. Phagocyte activity, and Fc gamma and complement receptor expression of phagocytes were assayed, and serum total IgE, milk-specific IgE, and serum reactivity to milk protein were determined. The challenge increased phagocyte activity and complement receptor expression of phagocytes in subjects designated milk-hypersensitive, who had gastrointestinal symptoms from milk ingestion but normal lactose tolerance. The increase was not detected in lactose-intolerant or control subjects. The milk-hypersensitive group was also distinguished from the lactose-intolerant group by enhanced serum reactivity to milk protein. Only two out of nine milk-hypersensitive subjects had detectable milk-specific serum IgE. It is concluded that milk hypersensitivity in adults, occurring as gastrointestinal reactions, may be more common than previously thought.

Cow-milk allergy

Hereditary predisposition is the major denominator of allergy, and hypersensitivity reactions contribute to the expression of the genetic predisposition. The route of sensitization varies with age so that dietary antigens predominate in infancy. The immaturity of the immune system and the gastrointestinal barrier may explain the peak prevalence of food allergies at an early age. The treatment of choice for cow-milk allergy is complete avoidance of cow-milk antigens. The approach to control allergic inflammation by antigen elimination, however, has not been satisfactory. New approaches are urgently needed for the management of patients with cow-milk allergy. These may include: (i) immunotherapy to counteract the immunological dysfunction, and (ii) stabilisation of the gut mucosal barrier to strengthen endogenous defence mechanisms.