Jonard P P, Rambaud J C, Dive C, Vaerman J P, Galian A, Delacroix D L
J Clin Invest. 1984 Aug;74(2):525-35. doi: 10.1172/JCI111450.
Parameters of secretion of IgA and several other plasma proteins from the jejunal mucosa were investigated in 11 individuals who had a normal distribution of Ig-containing cells in the lamina propria and in one patient who was totally deficient in jejunal IgA and IgM plasmacytes. Jejunal samples were collected during segmental gut perfusion. The following results were obtained: (a) The secretion of polymeric IgA (p-IgA, mean equals 217 micrograms/40 cm per min) exceeded those of albumin (132 micrograms), IgG (35 micrograms), and monomeric IgA (m-IgA, 15 micrograms, or 6.4% of total IgA). About 35% of IgA was IgA2 in the jejunal secretion, compared with approximately 23% in serum. This closely corresponds to the 35 and 24% of IgA2 plasmocytes in jejunal mucosa and peripheral lymph nodes, respectively. (b) For each protein, a relative coefficient of excretion (RCE) was calculated (jejunum to serum concentration ratio expressed relative to that of albumin). RCEs of 1.41 for orosomucoid, 1.0 for albumin, 0.83 for IgG, and 0.74 for IgE and, in the deficient patient, of 0.64 for m-IgA and 0.016 for IgM were obtained. This was inversely related to the molecular weight of these proteins and indicated their predominantly passive transport into the jejunum. However, in normal individuals, the RCE of transferrin (approximately 1.11 greater than 1, P greater than 0.05), alpha 2-macro globulin (approximately 0.77), m-IgA (approximately 1.98), and p-IgA (approximately 218) exceeded the value expected from simple seepage from plasma, thus pointing to an additional role of either local gut synthesis and/or active transepithelial transport. (c) Approximately 98% of p-IgA, approximately 99% of IgM, and approximately 68% of m-IgA in jejunal secretions were derived from local production in the gut wall, as determined by 125I-p-IgA specific activities and/or by comparison between the RCE values of the deficient patient to the values of controls. Therefore, the jejunal production of p-IgA (approximately 312 mg/d per 40 cm vs. approximately 54 mg/d from bile) contributes the majority of upper intestinal IgA in humans. The active transport of plasma p-IgA across the intestinal mucosa (approximately 0.08 mg/40 cm per kg per d) contributes less than 2% of the total amount of p-IgA (4.5 mg/kg per d) that is cleared daily from plasma.
对11名固有层含免疫球蛋白细胞分布正常的个体以及1名空肠IgA和IgM浆细胞完全缺乏的患者的空肠黏膜分泌IgA和其他几种血浆蛋白的参数进行了研究。在肠道节段灌注期间采集空肠样本。获得了以下结果：(a) 聚合IgA（p-IgA，平均值等于217微克/40厘米每分钟）的分泌量超过白蛋白（132微克）、IgG（35微克）和单体IgA（m-IgA，15微克，占总IgA的6.4%）。空肠分泌物中约35%的IgA为IgA2，而血清中约为23%。这与空肠黏膜和外周淋巴结中分别为35%和24%的IgA2浆细胞密切对应。(b) 对于每种蛋白质，计算了相对排泄系数（RCE）（空肠与血清浓度比相对于白蛋白表示）。获得了以下RCE值：类粘蛋白为1.41，白蛋白为1.0，IgG为0.83，IgE为0.74，在缺乏的患者中，m-IgA为0.64，IgM为0.016。这与这些蛋白质的分子量呈负相关，表明它们主要通过被动转运进入空肠。然而，在正常个体中，转铁蛋白（约1.11大于1，P大于0.05）、α2-巨球蛋白（约0.77）、m-IgA（约1.98）和p-IgA（约218）的RCE超过了从血浆简单渗漏预期的值，因此表明局部肠道合成和/或主动跨上皮转运有额外作用。(c) 根据125I-p-IgA比活性和/或通过比较缺乏患者与对照的RCE值确定，空肠分泌物中约98%的p-IgA、约99%的IgM和约68%的m-IgA源自肠壁的局部产生。因此，空肠产生的p-IgA（约312毫克/天每40厘米对胆汁中的约54毫克/天）占人类上肠道IgA的大部分。血浆p-IgA跨肠黏膜的主动转运（约0.08毫克/40厘米每千克每天）占每天从血浆清除的p-IgA总量（约4.5毫克/千克每天）的不到2%。
