Department of Gastroenterology at Guy's & St. Thomas NHS Foundation Trust, London, UK.
Inflamm Bowel Dis. 2010 Jun;16(6):1051-60. doi: 10.1002/ibd.21169.
Orofacial granulomatosis (OFG) is a chronic, disfiguring, granulomatous inflammation of the lips and oral mucosa. The pathogenesis is unknown, but it has been linked previously to Crohn's disease (CD) and more recently to dietary sensitivity. The oral mucosa is an immunologically responsive site associated with the generation of protective mucosal and systemic immune responses to vaccination and also hyperresponsiveness to allergens in some individuals. Classically, immune responses in oral mucosa are considered to be mediated by mucosa-associated lymphoid tissues (MALT), secondary lymphoid follicles that are intimately associated with epithelia.
Immunohistochemistry was used to investigate the inflammatory infiltrate in OFG and control tissue samples. Polymerase chain reaction (PCR), cloning of PCR products, and sequencing were used to characterize the local immunoglobulin gene profile in OFG.
We describe large, active, dendritic B cells in oral mucosa that were not associated with any organized lymphoid tissues in the local subepithelial microenvironment. They express activation induced cytidine deaminase, which is essential for immunoglobulin gene diversification by somatic hypermutation and class switch recombination. IgE is also expressed by these B cells. They do not align with any other previously described B-cell subset in secondary lymphoid tissues in terms of morphology, proliferative activity, or phenotype.
These subepithelial dendritic B cells may contribute to the immune responsiveness of the oral mucosa, including IgE-mediated allergic responses. In patients with OFG, further understanding of the role these cells play in oral immunity may lead to novel therapeutic possibilities.
口面肉芽肿病（OFG）是一种慢性、毁容性、肉芽肿性唇和口腔黏膜炎症。其发病机制尚不清楚，但以前与克罗恩病（CD）有关，最近与饮食敏感有关。口腔黏膜是一个具有免疫反应性的部位，与疫苗接种产生保护性黏膜和全身免疫反应以及某些个体对过敏原的高反应性有关。经典地，口腔黏膜中的免疫反应被认为是由黏膜相关淋巴组织（MALT）介导的，MALT 是与上皮密切相关的次级淋巴滤泡。
我们使用免疫组织化学方法研究 OFG 和对照组织样本中的炎症浸润。聚合酶链反应（PCR）、PCR 产物的克隆和测序用于描述 OFG 中的局部免疫球蛋白基因谱。
我们描述了口腔黏膜中大量活跃的树突状 B 细胞，这些细胞与局部上皮下微环境中的任何组织淋巴组织都没有关联。它们表达激活诱导的胞苷脱氨酶，这对于通过体细胞超突变和类别转换重组进行免疫球蛋白基因多样化是必不可少的。这些 B 细胞也表达 IgE。就形态、增殖活性或表型而言，它们与次级淋巴组织中任何其他先前描述的 B 细胞亚群都不相符。
这些上皮下树突状 B 细胞可能有助于口腔黏膜的免疫反应性，包括 IgE 介导的过敏反应。在 OFG 患者中，进一步了解这些细胞在口腔免疫中所起的作用可能会带来新的治疗可能性。
