Mäki M
Department of Clinical Science, University of Tampere, Finland.
Baillieres Clin Gastroenterol. 1995 Jun;9(2):231-49. doi: 10.1016/0950-3528(95)90030-6.
IgA is transported into intestinal secretions to perform exclusion of luminal antigens. The prerequisites are antigen sampling by the Peyer's patch M cells, antigen processing by antigen-presenting cells, and presentation of antigenic peptides by HLA class II molecules to immunocompetent T-cells. The basis for intestinal immunity is the maturation cycle of specifically primed T and B cells from the gut-associated lymphoid tissue via mesenteric lymph nodes and peripheral blood back to the intestinal lamina propria. In coeliac disease, patients are sensitized against gluten and serum gliadin antibodies are often detected. Gliadin antibodies are also found in other gastrointestinal diseases, other disorders and in healthy individuals not carrying the coeliac disease-specific DQA/DQB alleles. On the other hand, serum reticulin and endomysium autoantibodies are both sensitive and highly disease-specific. Positivity in patients with normal jejunal morphology indicates latency of coeliac disease. These tissue autoantibodies are directed against fibroblast-derived extracellular matrix proteins. The immune system is involved in the amplification and perpetuation of the abnormalities of the intestinal mucosa in coeliac disease. The role of antibody in the pathogenesis remains unknown. The author hypothesizes gluten-triggered autoimmune mechanism to be operative.
IgA被转运至肠道分泌物中以排除管腔抗原。其前提条件是派尔集合淋巴结M细胞进行抗原采样、抗原呈递细胞进行抗原加工，以及通过HLA II类分子将抗原肽呈递给免疫活性T细胞。肠道免疫的基础是特异性致敏的T细胞和B细胞从肠道相关淋巴组织经肠系膜淋巴结和外周血回到肠固有层的成熟循环。在乳糜泻患者中，对麸质敏感，常可检测到血清麦醇溶蛋白抗体。在其他胃肠道疾病、其他病症以及未携带乳糜泻特异性DQA/DQB等位基因的健康个体中也发现了麦醇溶蛋白抗体。另一方面，血清网硬蛋白和肌内膜自身抗体既敏感又具有高度疾病特异性。空肠形态正常的患者呈阳性表明乳糜泻处于潜伏期。这些组织自身抗体针对成纤维细胞衍生的细胞外基质蛋白。免疫系统参与了乳糜泻中肠黏膜异常的放大和持续存在。抗体在发病机制中的作用尚不清楚。作者推测麸质触发的自身免疫机制起作用。
