孕妇及新生儿体内B组链球菌Ⅲ型特异性IgG抗体水平的研究

目的　测定一组孕妇及其新生儿体内 B组链球菌 (GBS) 型特异性 Ig G抗体的水平 ,初步探讨国内新生儿 GBS感染的发生率较低的原因。　方法　随机选取 10 2例孕妇 ,取其静脉血及新生儿脐血测定 GBS 型特异性抗体含量 ,取 6 2例 1周龄以内的新生儿及 32例 2个月～ 13岁的健康查体儿童的静脉血作为对照 ,也测定该抗体含量 ;抗体检测方法为酶联免疫试验 (EL ISA )。　结果　本组孕妇 GBS 型特异性 Ig G抗体的平均水平为 2 1.5 9mg/ L ,新生儿脐血该抗体的平均水平为 17.90 mg/ L ,二者存在相关性 (r=0 .83,P<0 .0 5 ) ,后者随孕周增加而增加 ;小于 1周龄的新生儿该抗体平均水平为 14.75 mg/ L ,2个月～ 13岁儿童该抗体平均水平为 10 .75 mg/ L ,四组之间差异有显著性 ,并逐渐下降 (P<0 .0 5 )。　　结论　 (1)所测值绝大多数大于 2 m g/ L这个被初步认为能起保护作用的水平 ,并且明显高于欧美国家 ,提示由于国内孕妇天然获得的抗体水平较高 ,对新生儿 GBS感染提供保护作用 ,这可能是我国新生儿感染发生率低的原因之一。 (2 )新生儿体内该抗体来源于母体 ,随年龄增加而降低。(3)新生儿脐血中该抗体含量与母亲产前静脉血含量密切相关 ,且随孕周的增加而增加。提示 Ig G型抗体经胎盘的主动转运与孕周相关 ,早

GBS Type Ⅲ Specific IgG Antibody Level in Prenatal Mother and Neonatal Cord Serums

Objective To explore the reason of low incidence of neonatal GBS infection in China. Methods The serum level of GBS type III specific antibody in 102 randomly selected prenatal mother and their neonatal cord blood were measured using ELISA method. Sixty-two neonates less than 7 days old and 32 children between 2 months and 13 years old served as control. Results The average level of GBS type III specific antibody in the mother was 21.59 mg/L, and that in the paired cord serum was 17.90 mg/L, which was correlate with their mother(r=0.83,P<0.05) and increased as the gestational age increased. In the neonates less than 7 days the level of the antibody was 14.75 mg/L,and in the children between 2 months and 13 years old it was 10.75 mg/L. The level of the antibody decreased(P<0.05) when the children went old. Conclusions (1) Comparing our results with data from other countries such as USA, Sweden and Gambia, the antibody level was significantly higher in our cases, and antibody level higher than 2 mg/L is considered highly protective. So the incidence of GBS infection is relatively low in China maybe because of the relatively higher le- vel of antibody which is nature acquired. (2) The antibody in the newborns were transferred from the mothers through placenta and decreased as the age increased. (3) Preterm babies are easier to suffer from GBS infection due to the deficiency of mother-derived antibody.