Soy Gly m 8 sIgE Has Limited Value in the Diagnosis of Soy Allergy in Peanut Ara h 2-Sensitized Adults

INTRODUCTION

Recently, specific IgE (sIgE) sensitization against Gly m 8 (soy 2S albumin) has been described as a good diagnostic marker for soy allergy (SA). The aim of this study was to evaluate the diagnostic value of Gly m 8 by determining the sensitization profiles based on the homologues soy allergens Bet v 1, Ara h 1, Ara h 2, and Ara h 3.

METHODS

Thirty soy-allergic adults were included; sIgE to total soy extract, Gly m 8, Gly m 4, Gly m 5, Gly m 6, Bet v 1, Ara h 1, Ara h 2, and Ara h 3 were determined. Sensitization patterns were analyzed and determined. The clinical relevance of sIgE of Gly m 8 sensitization was measured by assessing its capacity to degranulate basophils in Gly m8-sensitized patients by an indirect basophil activation test (iBAT).

RESULTS

Based on the sIgE patterns of sensitization, two groups of SA patients were identified: (i) peanut-associated SA group (all patients were sensitized to one or more of the peanut compounds) and (ii) non-peanut/PR-10-associated SA group (22 patients were sensitized to Gly m 4 and Bet v 1 but not to any of the peanut compounds). A high and significant correlation between total soy extract and Gly m 6 (R2 = 0.97), Gly m 5 (R2 = 0.85), and Gly m 8 (R2 = 0.78) was observed. A nonsignificant correlation was observed between the levels of sIgE of Gly m 8 versus Ara h2. The iBAT results showed that Gly m 8 did not induce basophil degranulation in any of the peanut-associated patients, indicating that the Gly m8 sensitizations were not clinically relevant.

CONCLUSIONS

Gly m 8 was not a major allergen in the selected soy-allergic population. The iBAT results indicated that Gly m 8 was not able to induce basophil degranulation in sIgE Gly m 8-sensitized soy-allergic patients. Thus, Gly m 8 would have no added value in the diagnosis of SA in the present study population.

Maternal and Fetal Determinants of Neonatal Body Composition

BACKGROUND

Body composition in early life influences the development of obesity during childhood and beyond. It is, therefore, important to adequately determine neonatal body composition. Fetal growth and maternal factors might influence neonatal fat mass percentage (FM%), independent of birth weight.

METHODS

In 194 healthy neonates, we investigated neonatal body composition, measured by air-displacement plethysmography (PEAPOD), and its associations with estimated fetal weight (EFW), neonatal anthropometric data, maternal preconceptional body mass index (BMI) and maternal weight gain during pregnancy.

RESULTS

There was a large variation in neonatal FM%, even in case of a similar birth weight, corrected for gender and gestational age. Neonatal FM% was associated with EFW at 30 and 36 weeks of gestation and with catch-up in weight between 30 and 36 weeks of gestation, but not with EFW at 20 weeks (p < 0.01, p < 0.01 and p = 0.64, respectively). Neonatal FM% was also associated with preconceptional BMI of the mother (p < 0.01). There was no correlation with maternal weight gain.

CONCLUSION

Our study shows that term neonates have a large variation in FM%. Neonatal FM% is associated with EFW at 30 and 36 weeks, catch-up in weight between 30 and 36 weeks of gestation and preconceptional BMI of the mother.