Jones A C, Miles E A, Warner J O, Colwell B M, Bryant T N, Warner J A
Department of Child Health, University of Southampton, England.
Pediatr Allergy Immunol. 1996 Aug;7(3):109-16. doi: 10.1111/j.1399-3038.1996.tb00117.x.
Blood samples were obtained from fetuses and premature babies (n = 51) (15-34 weeks gestation) to determine at what stage the fetal immune system was able to produce a positive proliferative response to common allergens. Peripheral blood mononuclear cells (PBMC) were stimulated with the mitogen, phytohaemagglutinin (PHA), and the allergens, house dust mite, cat fur, birch tree pollen, beta-lactoglobulin, ovalbumin and bee venom (mellitin). Results were expressed as ratios of stimulated to unstimulated 3H thymidine incorporation, and as percent positive responders. There was an increase in proliferation ratio which correlated with increasing gestational age for PHA (p < 0.0001), cat fur (p = 0.042), birch pollen (p = 0.022) and beta-lactoglobulin (p = 0.006). The point in gestation when cells from some individuals began responding to the allergens with a ratio of 2.0 was at approximately 22 weeks. PBMC proliferative response ratios were higher from samples from babies > 22 weeks gestation compared to < 22 weeks for the mitogen and all allergens, except mellitin. There was also a greater proportion of positive responders from samples > 22 weeks compared to < 22 weeks for the mitogen and all allergens, except mellitin. Maternal exposure to birch pollen, which has a discrete season, was assessed to determine whether exposure had occurred at 22 weeks gestation or beyond. Results showed a higher proliferative response in infant cells stimulated with birch pollen (p = 0.005) and higher proportion of positive responders (p = 0.01) in the group of babies whose mothers had been exposed to birch pollen beyond 22 weeks, compared to those whose mothers had not been so exposed. These results suggest that in utero fetal exposure to an allergen from around 22 weeks gestation may result in primary sensitisation to that allergen, leading to positive proliferative responses, at birth.
采集了胎儿和早产儿（n = 51）（妊娠15 - 34周）的血样，以确定胎儿免疫系统在哪个阶段能够对常见过敏原产生阳性增殖反应。用丝裂原植物血凝素（PHA）以及过敏原屋尘螨、猫毛、桦树花粉、β-乳球蛋白、卵清蛋白和蜂毒（蜂毒肽）刺激外周血单个核细胞（PBMC）。结果以刺激后与未刺激的3H胸苷掺入率之比以及阳性反应者百分比表示。PHA（p < 0.0001）、猫毛（p = 0.042）、桦树花粉（p = 0.022）和β-乳球蛋白（p = 0.006）的增殖率随胎龄增加而升高。一些个体的细胞开始以2.0的比率对过敏原产生反应的妊娠时间约为22周。与妊娠< 22周的样本相比，妊娠> 22周婴儿样本中，除蜂毒肽外，丝裂原和所有过敏原刺激后的PBMC增殖反应率更高。与妊娠< 22周的样本相比，妊娠> 22周的样本中，丝裂原和所有过敏原（除蜂毒肽外）的阳性反应者比例也更高。评估了孕妇在桦树花粉离散季节的暴露情况，以确定在妊娠22周及以后是否发生了暴露。结果显示，与母亲未暴露的婴儿组相比，母亲在妊娠22周后暴露于桦树花粉的婴儿组中，用桦树花粉刺激的婴儿细胞增殖反应更高（p = 0.005），阳性反应者比例更高（p = 0.01）。这些结果表明，妊娠约22周起胎儿在子宫内接触过敏原可能导致对该过敏原的初次致敏，从而在出生时产生阳性增殖反应。
