Detection of major food allergens in amniotic fluid: initial allergenic encounter during pregnancy.

BACKGROUND: Ingestion of food allergens present in maternal milk during breastfeeding has been hypothesized as a gateway to sensitization to food; however, this process could develop during pregnancy, as the maternal-fetal interface develops a Th2- and Treg-mediated environment to protect the fetus. We hypothesized that in these surroundings, unborn children are exposed to food allergens contained in the mother's diet, possibly giving rise to first sensitization. METHODS: The presence of allergens in utero was studied by analyzing amniotic fluid (AF) samples in two different stages of pregnancy: at 15-20 weeks and after delivery at term. An antibody microarray was developed to test for the most common food allergens. The array detects the presence of ten allergens from milk, fruit, egg, fish, nuts, and wheat. RESULTS: AF from 20 pregnant women was collected: eight after delivery at term and 12 from women who underwent diagnostic amniocentesis between weeks 15 and 20 of gestation. The presence of allergens was detected in all samples. Samples from amniocentesis had a higher allergen concentration than samples after delivery at term. CONCLUSIONS: We demonstrated the presence of intact major food allergens in AF samples. This early contact could explain subsequent sensitization to foods never eaten before.

Overview of Five-Years of Experience Performing Non-Invasive Fetal Sex Assessment in Maternal Blood.

Since the discovery of the presence of fetal DNA in maternal blood, non-invasive fetal sex determination has been the test most widely translated into clinical practice. To date there is no agreement between the different laboratories performing such tests in relation to which is the best protocol. As a consequence there are almost as many protocols as laboratories offering the service, using different methodologies and thus obtaining different diagnostic accuracies. By the end of 2007, after a validation study performed in 316 maternal samples collected between the 5th and 12th week of gestation, the fetal sex determination was incorporated into clinical practice in our Service. The test is performed in the first trimester of pregnancy, and it is offered as part of the genetic counseling process for couples at risk of X-linked disorders. As a general rule and in order to avoid misdiagnosis, two samples at different gestational ages are tested per patient. The analysis is performed by the study of the SRY gene by RT-PCR. Two hundred and twenty six pregnancies have been tested so far in these 5 years. Neither false positives nor false negatives diagnoses have been registered, thus giving a diagnostic accuracy of 100%.