Early expression of Iϵ, CD23 (FcϵRII), IL-4R⍺, and IgE in the human fetus - 04/09/11
Abstract |
Background: A major predictor of childhood atopy is the concentration of IgE in the cord blood, but whether the source of cord blood IgE is maternal or fetal remains unclear. Objective: We sought to determine the pattern of in situ IgE production during ontogeny. Methods: Ninety-seven fetal, 142 natal, and 96 childhood samples were analyzed by using reverse transcription PCR for transcription of VDJCϵ, Iϵ, and CD23. Thirty-eight fetal liver samples were analyzed for the IL4RA genotype. Results: IL-4R⍺, CD23a, CD23b, and sterile Iϵ transcripts were present as early as 8 weeks’ gestation. VDJCϵ transcripts were found in second-trimester fetal liver and third-trimester cord blood, although they were rare. VDJCϵ transcripts were more common in the blood of children 9 months and older. Sequence analysis suggested that fetal VDJCϵ was the product of selection. All fetal livers actively transcribing Iϵ, VDJCϵ, and IL-4R⍺ contained at least one copy of the atopy-associated IL4RA*A1902G polymorphism. Conclusion: The human fetus contains B cells that are primed to undergo IgE class switching from the earliest stages of ontogeny and can produce endogenous IgE by 20 weeks’ gestation. However, IgE-producing cells are rare until 9 months after birth. (J Allergy Clin Immunol 2000;106:911-7.)
Le texte complet de cet article est disponible en PDF.Keywords : IgE, immunoglobulin variable region, CD23, IL-4 receptor, receptors Fc, spleen, liver, cord blood, gut, mesentery, fetus, human
Abbreviations : RT:
Plan
![]() | Supported in part by NIH grants AI34568, DE11147, HD36292, and RR00032. |
![]() ![]() | Reprint requests: Harry W. Schroeder, Jr, MD, PhD, Division of Developmental and Clinical Immunology, Wallace Tumor Institute 378, 1530 3rd Ave South, University of Alabama at Birmingham, Birmingham, AL 35294. |
Vol 106 - N° 5
P. 911-917 - novembre 2000 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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