58对母婴麻疹抗体水平衰减的研究

目的 通过配对研究母亲及其分娩新生儿的麻疹抗体水平的动态变化过程,探询低月龄婴儿麻疹高发的原因,为制定麻疹免疫策略提供理论依据。 方法 采用横断面研究的方式,采集母亲外周血2 ml和分娩时脐带血(代表新生儿出生时的水平)2 ml,同时在婴儿3、5、7月龄时随访动态观察,采用德国IBL公司试剂ELESA方法测定血清中麻疹IgG抗体水平。 结果 孕产妇及新生儿脐带血的麻疹抗体滴度分别是:Max_孕妇=6 522,Min_孕妇=62,Med_孕妇=834.5和Max_脐带=6 233,Min_脐带=61,Med_脐带=760.5,两者差异无统计学意义(t=0.87,P=0.39)。母亲及婴儿脐带血麻疹血清抗体阳性率分别为84.48%和86.21%,血清抗体保护率分别为50.00%和46.55%。母婴麻疹血清抗体水平具有正相关性(r=0.83,P<0.01),婴儿脐带血抗体水平随母亲抗体水平的升高而升高(χ²=42.85,P<0.01)。婴儿麻疹抗体阳性率3月龄时为29.27%,5月龄时为5.88%,7月龄及以后全阴。母亲保护性抗体阳性者的婴儿脐带血保护性抗体阳性率(89.66%)比母亲保护性抗体阴性者的(3.45%)高(χ²=20.06,P<0.01)。不论母亲是否有保护性抗体,3月龄及以后各月龄时婴儿的麻疹保护性抗体阳性率均为0。 结论 目前新生儿麻疹抗体水平低且衰减速度快,7月龄时已经全部转阴,3月龄时婴儿胎传抗体已无保护性。育龄期妇女孕前麻疹抗体水平对婴儿麻疹抗体水平有直接影响,孕前接种麻疹疫苗可在一定程度上提高婴幼儿麻疹抗体水平。

Attenuation of measles antibody in 58 pairs of mothers and neonates

Objective To make a matched-pair study on the dynamic changes of measles antibody level in mothers and their neonates, to explore the causes of the high incidence rate of measles in newborn infants so as to provide theoretical evidence for formulating measles immunization strategy. Methods A cross-sectional study was made. 2 ml maternal peripheral blood and 2 ml umbilical cord blood (UCB) during parturition, which informed a neonate’s initial antibody level at birth, were collected in 58 pairs of mothers and their neonates. A follow-up study was conducted among the neonates at the 3rd, 5th and 7th months after birth. The serum IgG antibody levels of the mothers and neonates were determined by ELESA with reagents from German LBL Company. Results The measles antibody titers in sera of mothers during pregnancy (maximum 6,522, minimum 62, median 834.5) and in UCB of neonates (maximum 6,233, minimum 61, median 760.5) were not significantly different (t=0.87, P=0.39). The serum antibody positive rates and antibody protective rates in the mothers and UCB of the neonates were 84.48% and 86.21%, 50.00% and 46.55% respectively. There was a positive correlation between the maternal measles antibody level and the neonates’ (r=0.83, P<0.01). The antibody levels in the UCB of the neonates were elevated with the increase of their mothers’ antibody levels (χ²=42.85, P<0.01). The positive rates of serum antibody in the neonates at the 3rd and 5th months were 29.27% and 5.88% respectively, but the serum antibody turned to be negative in all neonates at the 7th months and thereafter. The positive rate of protective antibody in the UCB of the neonates with positive- antibody mothers was higher than that of those with negative-antibody mothers (89.66% vs. 3.45%, χ²=20.06, P<0.01). The positive rate of measles protective antibody in the neonates at the 3rd month and thereafter decreased to 0 despite their mothers with or without the protective antibody. Conclusions The measles antibody level in the neonates is low and falls rapidly. Maternal-transferred measles antibody turns to be negative in the neonates at the 7th month; moreover, it is not protective since the 3rd month. The measles antibody levels of the neonates are directly influenced by those of women of childbearing age. Pre-pregnancy vaccination can improve the neonates’ measles antibody in a certain degree.