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 VDJCepsilon, Iepsilon, and CD23. Thirty-eight fetal liver samples were analyzed for the IL4RA genotype. RESULTS: IL-4Ralpha, CD23a, CD23b, and sterile Iepsilon transcripts were present as early as 8 weeks' gestation. VDJCepsilon transcripts were found in second-trimester fetal liver and third-trimester cord blood, although they were rare. VDJCepsilon transcripts were more common in the blood of children 9 months and older. Sequence analysis suggested that fetal VDJCepsilon was the product of selection. All fetal livers actively transcribing Iepsilon, VDJCepsilon, and IL-4Ralpha 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.
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 VDJCepsilon, Iepsilon, and CD23. Thirty-eight fetal liver samples were analyzed for the IL4RA genotype. RESULTS:IL-4Ralpha, CD23a, CD23b, and sterile Iepsilon transcripts were present as early as 8 weeks' gestation. VDJCepsilon transcripts were found in second-trimester fetal liver and third-trimester cord blood, although they were rare. VDJCepsilon transcripts were more common in the blood of children 9 months and older. Sequence analysis suggested that fetal VDJCepsilon was the product of selection. All fetal livers actively transcribing Iepsilon, VDJCepsilon, and IL-4Ralpha 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.
Authors: E Rindsjö; I Hulthén Varli; M F Ofori; M Lundquist; U Holmlund; N Papadogiannakis; A Scheynius Journal: Clin Exp Immunol Date: 2006-05 Impact factor: 4.330
Authors: E Sverremark Ekstrom; C Nilsson; U Holmlund; I van der Ploeg; B Sandstedt; G Lilja; A Scheynius Journal: Clin Exp Immunol Date: 2002-02 Impact factor: 4.330