Lucidarme D, Colombel J F, Brandtzaeg P, Tulliez M, Chaussade S, Marteau P, Dehennin J P, Vaerman J P, Rambaud J C
Laboratoire d'Explorations Fonctionelles Digestives, Centre Hospitalier Regional Universitaire, Lille, France.
Gastroenterology. 1993 Jan;104(1):278-85. doi: 10.1016/0016-5085(93)90863-8.
It is unclear why different forms of alpha-chain disease protein appear in intestinal fluid. This was studied in a 23-year-old Mauritanian man in whom alpha-chain disease was diagnosed localized to the duodenum and jejunum, nasopharynx, and bone marrow.
The duodenal infiltrate was studied by immunohistochemistry. Forms of alpha chain-containing proteins in serum and jejunal fluid were analyzed by ultracentrifugation and radioimmunoassays.
The infiltrating cells contained alpha-1 chain but no light chains, and approximately 66% showed variable expression of J chain. Serum contained a large fraction of monomeric alpha-chain disease protein, whereas both monomeric and heavier forms appeared in jejunal fluid. Some of the latter were bound to secretory component, and the fluid contained virtually no free component.
Linkage of polymeric alpha-chain disease protein to secretory component depends on balanced synthesis of alpha chains and J chain in the proliferating B cells, giving rise to polymers with binding site for secretory component expressed as an epithelial receptor. Insufficient receptor-mediated transport capacity (either relative and/or because of intestinal crypt reduction) results in passive external transfer of polymers without bound secretory component along with leakage of serum-derived or locally produced monomeric alpha-chain disease protein, the latter presumably originating from immunocytes with little or no J-chain synthesis.
尚不清楚为何不同形式的α链疾病蛋白会出现在肠液中。我们对一名23岁的毛里塔尼亚男性进行了研究，该男性被诊断患有局限于十二指肠和空肠、鼻咽部及骨髓的α链疾病。
通过免疫组织化学研究十二指肠浸润情况。通过超速离心和放射免疫测定分析血清和空肠液中含α链蛋白的形式。
浸润细胞含有α-1链但无轻链，约66%的细胞显示J链表达可变。血清中含有大部分单体α链疾病蛋白，而单体和较重形式的蛋白均出现在空肠液中。后者中的一些与分泌成分结合，且该液体中几乎不含游离成分。
聚合α链疾病蛋白与分泌成分的连接取决于增殖B细胞中α链和J链的平衡合成，从而产生具有分泌成分结合位点的聚合物，该位点表现为上皮受体。受体介导的转运能力不足（无论是相对不足和/或由于肠隐窝减少）导致聚合物在无结合分泌成分的情况下被动向外转移，同时血清来源或局部产生的单体α链疾病蛋白泄漏，后者可能源自几乎不合成或不合成J链的免疫细胞。
