Study on the Concentrations of Cerebrospinal Fluid Immunoglobulin G and Albumin in Children

小兒脊髓液IgG及白蛋白之研究

洪焜隆(Kun-Long Hung) ； 張明道(Mine-Tao Chang) ； 蔡明蘭(Min-Lan Tsai) ； 陳五常(Wu-Charng Chen)

《Acta Paediatrica Sinica》 33卷5期 (1992/10) Pp. 325-331

摘要

在正常生理狀況下，脊髓液(CSF)之蛋白質如IgG及白蛋白等皆由血液滲透而來，由於有血腦障蔽（blood-brain barrier，簡稱BBB）的關係，正常人只有少量之IgG及白蛋白存在於脊髓液中。
為研究正常BBB之發育情形，著者在過去三年內收集出生至十五歲“正常”（無中樞神經系統病變）小孩之脊髓液共118例，依不同年齡層分為(l)新生兒，25例；(2)1至3個月，38例：(3)3至6個月，12例：(4)6至12個月，12例；(5)l至5歲，11例：(6)5至10歲，10例及(7)10至15歲，10例等七組。將每例脊髓液與同時採取的血清檢體以rate nephelometer測定其IgG及白蛋白值，並依其值計算每例之CSF與血清之IgG比值(IgG ratio)、白蛋白比值(albomin ratio)及IgG index（IgG比值／白蛋白比值）。結果發現脊髓液與血清之IgG及白蛋白值隨著年齡而有所變化。脊髓液之IgG值與IgG比值在出生後逐漸降低，直至六個月後漸趨穩定，而白蛋白比值則繼續下降至一歲以後才趨穩定，顯示BBB對於較小分子的白蛋白有較大的透過性。而一歲以後BBB的功能益趨完全，以至於IgG及白蛋白等蛋白質在高的血清濃度下，只能維持少量的比率進入脊髓液中。至於IgG index則在各年齡層維持恆定狀態；顯示在沒有中樞神經系統感染或發炎情況下此值之穩定性，可以做為神經系統感染或發炎之指標。

並列摘要

Concentrations of immunoglobulin G (IgG) and albumin in cerebrospinal fluid (CSF) and serum were measured in 118 ”normal” Chinese children from birth to 15 years old to obtain the reference values for the evaluation of the blood-brain barrier (BBB) function. The values of the CSF/serum IgG ratio, CSF/serum albumin ratio and IgG index (IgG ratio/albumin ratio) were then calculated for each subject. A relation was found between the content of IgG in CSF and serum depending on age. The gradual decrease of CSF IgG and IgG ratio during the first 6 months indicated a postnatal impediment of the diffusion of IgG from the blood to the CSF. In the meanwhile the CSF/serum albumin ratio continued to drop until the age of one year. The slower slope of the decrement of the latter ratio further demonstrated the differential permeability of the BBB in favor of the shift of small molecular protein. The change of the protein permeability within the first year of life shows a characteristic of the maturational process of the BBB. Nevertheless, IgG index has no age-dependent variation throughout the childhood period. It remains constant in the absence of inflammation within the central nervous system.

並列關鍵字

CSF IgG ； IgG index ； blood-brain barrier