Harrison Linda M, Morris James A, Bishop Lisa A, Lauder Robert M, Taylor Christine A M, Telford David R
Department of Pathology, Royal Lancaster Infirmary, Lancaster LA1 4RP, UK.
FEMS Immunol Med Microbiol. 2004 Sep 1;42(1):94-104. doi: 10.1016/j.femsim.2004.06.010.
The common bacterial toxins hypothesis of sudden infant death syndrome (SIDS) is that nasopharyngeal bacterial toxins can trigger events leading to death in infants with absent/low levels of antibody that can neutralise the toxins. The aim of this study was to investigate nasopharyngeal carriage of Staphylococcus aureus and determine levels of immunity in the first year of life to toxic shock syndrome toxin (TSST-1) and staphylococcal enterotoxin C (SEC). Both toxins have been implicated in SIDS cases. Seventy-three mothers and their infants (39 males and 34 females) were enrolled onto the study. The infants had birth dates spread evenly throughout the year. In infants, S. aureus carriage decreased significantly with age (P<0.001). Between 40% and 50% of infants were colonised with S. aureus in the first three months of life and 49% of the isolates produced one or both of the staphylococcal toxins. There was a significant correlation between nasopharyngeal carriage of S. aureus in mothers and infants in the three months following the birth (P<0.001). Carriage of S. aureus in infants and their mothers was not significantly associated with levels of antibody to TSST-1 or SEC in cord blood, adult saliva or breast milk. Infants colonised by S. aureus had higher levels of salivary IgA to TSST-1 than infants who were culture negative. Analysis of cord blood samples by a quantitative ELISA detected IgG bound to TSST-1 and SEC in 95.5% and 91.8% of cases respectively. There was a marked variation in levels of maternal IgG to both TSST-1 and SEC among cord blood samples. Maternal age, birth weight, and seasonality significantly affected the levels of IgG binding to TSST-1 or SEC. Analysis of infant saliva samples detected IgA to TSST-1 and SEC in the first month after birth; 11% of samples tested positive for salivary IgA to TSST-1 and 5% for salivary IgA to SEC. By the age of two months these proportions had increased to 36% and 33% respectively. More infants who used a dummy tested positive for salivary IgA to TSST-1 compared to infants who did not use a dummy. Levels of IgA to TSST-1 and SEC detected in the breast-milk samples varied greatly among mothers. There was a trend for infants receiving breast milk with low levels of antibody to TSST-1 or SEC to have higher levels of salivary antibody to the toxins. In conclusion, passive immunity to toxins implicated in SIDS cases varies greatly among infants. Infants are able to mount an active mucosal immune response to TSST-1 and SEC in the first month of life.
婴儿猝死综合征（SIDS）的常见细菌毒素假说是，鼻咽部细菌毒素可引发一系列事件，导致抗体水平缺失/较低、无法中和毒素的婴儿死亡。本研究的目的是调查金黄色葡萄球菌在鼻咽部的携带情况，并确定婴儿出生后第一年对中毒性休克综合征毒素（TSST-1）和葡萄球菌肠毒素C（SEC）的免疫水平。这两种毒素都与SIDS病例有关。73名母亲及其婴儿（39名男性和34名女性）参与了该研究。婴儿的出生日期在全年均匀分布。在婴儿中，金黄色葡萄球菌的携带率随年龄显著下降（P<0.001）。在出生后的前三个月，40%至50%的婴儿被金黄色葡萄球菌定植，49%的分离株产生一种或两种葡萄球菌毒素。母亲和婴儿在出生后三个月内，金黄色葡萄球菌在鼻咽部的携带情况存在显著相关性（P<0.001）。婴儿及其母亲金黄色葡萄球菌的携带情况与脐带血、成人唾液或母乳中TSST-1或SEC的抗体水平无显著关联。被金黄色葡萄球菌定植的婴儿唾液中针对TSST-1的IgA水平高于培养阴性的婴儿。通过定量ELISA分析脐带血样本，分别在95.5%和91.8%的病例中检测到与TSST-1和SEC结合的IgG。脐带血样本中母亲针对TSST-1和SEC的IgG水平存在显著差异。母亲年龄、出生体重和季节显著影响与TSST-1或SEC结合的IgG水平。对婴儿唾液样本的分析在出生后第一个月检测到针对TSST-1和SEC的IgA；11%的样本唾液中针对TSST-1的IgA检测呈阳性，5%针对SEC的IgA检测呈阳性。到两个月大时，这些比例分别增至36%和33%。与不使用安抚奶嘴的婴儿相比，使用安抚奶嘴的婴儿唾液中针对TSST-1的IgA检测呈阳性的更多。母乳样本中检测到的针对TSST-1和SEC的IgA水平在母亲之间差异很大。接受TSST-1或SEC抗体水平较低的母乳的婴儿，其唾液中针对这些毒素的抗体水平有升高的趋势。总之，婴儿对与SIDS病例相关毒素的被动免疫存在很大差异。婴儿在出生后的第一个月就能对TSST-1和SEC产生活跃的黏膜免疫反应。
