Immunological study of pathogenesis and fibrosis in autoimmune pancreatitis

自身免疫性胰腺炎(AIP)是胰腺疾病的一个新的临床实体。有几种免疫学和组织学异常是该病特有的，包括血清IgG4水平升高，淋巴细胞和IgG4阳性浆细胞的渗透。近年来，调节性T细胞(Tregs)参与了多种自身免疫性疾病的发生和B细胞向IgG4的转化。为了阐明Treg在AIP病理生理学中的作用，我们分析了AIP中的循环Treg。我们招募了28名MP患者作为研究对象。为了进行比较，我们还招募了23名其他各种胰腺疾病患者和32名健康受试者作为对照。用流式细胞仪分析外周血中的Tregs为CD4+CD25High和CD4+CD25+CD45RA+(Naive)。酒精性慢性胰腺炎(CP)、特发性…患者外周血中CD_4~+CD_(25)高T细胞比例(2.99±1.75%)显著高于酒精性慢性胰腺炎(1.65±0.58%，P<0.05)。C-CP(1.53±0.56%，p&lt；0.05)高于健康对照组(1.72±0.81%，p&lt；0.05)。MP组幼稚Tregs(0.32±0.22%，p&lt；0.005)显著低于健康对照组(0.83±0.65%)。AIP组幼稚Tregs较酒精性CP(0.60±0.45%)和特发性CP(0.41±0.31%)有下降趋势(p=0.08)。在初治MP患者中，幼稚Tregs数与IgG4值呈正相关(R=0.286)。CD4+CD25High Tregs数量的增加可能影响空气中IgG4的产生，而幼稚Tregs数量的减少可能参与AIP的发病机制。我们还利用Wistar Bonn/Kobori大鼠(WBN/KOB大鼠)建立了自身免疫性胰腺炎的动物模型，该模型是一种自发性慢性胰腺炎模型，具有广泛分布的纤维化和实质变性，并伴有淋巴细胞的浸润。除胰腺炎外，WBN/KOB大鼠3月龄出现泪囊炎，18月龄以上出现涎腺炎、甲状腺炎、硬化性胆管炎，甚至小管间质性肾炎。损伤胰腺和泪腺中CD8~+细胞浸润，组织特异性IgG2b沉积。此外，WBN/KOB大鼠外周血中的调节性T细胞(Tregs)即CD4^+Foxp3^+细胞减少，提示这些疾病的发生至少是由于维持外周免疫耐受失败所致。这些特征清楚地表明WBN/KOB大鼠可以作为人类自身免疫性胰腺炎伴干燥样综合征或多灶性纤维硬化的有用动物模型。我们还表明，这些自身免疫性疾病可以通过一种新设计的骨髓移植(BMT)策略来预防，这种策略将骨髓细胞(BMC)直接注入骨髓腔；骨髓内BMT(IBM-BMT)。这些结果证实WBN/KOB大鼠是第一个人类AIP和多灶性纤维硬化的自发动物模型。综上所述，我们在人和动物模型中确认了调节性T细胞在自身免疫性胰腺炎发生发展中的作用。较少

Autoimmune pancreatitis (AIP) is a new clinical entity of pancreatic disorder. There are several immunologic and histologic abnormalities specific for the disease, including increased levels of serum IgG4, and infiltration of lymphocytes and IgG4-positive plasmacytes. The role of IgG4 is unclean Recently regulatory T cells (Tregs) have been reported to be involved in the development of various autoimmune diseases and B-cell shifting to IgG4. To clarify the role of Treg in pathophysiology of AIP, we analyzed circulating Tregs in AIP.We recruited 28 patients with MP for this study. For comparison, we also recruited 23 patients with various other pancreatic diseases and 32 healthy subjects as controls. We analyzed Tregs as CD4+CD25high and CD4+CD25+CD45RA+ (naive) from peripheral blood by flow cytometry. In peripheral blood, CD4+CD25high Tregs were significantly increased in AIP patients (2.99±1.75%, p<0.05) compared with alcoholic chronic pancreatitis (CP) (1.65±0.58%, p<0.05), idiopathi … More c CP (1.53±0.56%, p<0.05), and healthy control (1.72±0.81%, p<0.05). Naive Tregs significantly decreased in MP (0.32±0.22%, p<0.005) compared with healthy control (0.83±0.65%). Naive Tregs in AIP tended to be decreased compared with alcoholic CP (0.60±0.45%) and idiopathic CP (0.41±0.31%) (p=0.08). In untreated MP patients, the number of naive Tregs and IgG4 are correlated (R=0.286). Increased number of CD4+CD25high Tregs may influence IgG4 production in AIR while decreased number of naive Tregs may be involved in pathogenesis in AIP.We also established an animal model of autoimmune pancreatitis using Male Wistar Bonn/Kobori rat (WBN/Kob rat), which is a model of spontaneous chronic pancreatitis with widely distributed fibrosis and degeneration of parenchyma with the infiltration of lymphocytes. In addition to pancreatitis, we demonstrated dacryoadenitis in 3 months of age, and sialadenitis, thyroditis, sclerotic cholangitis and even tubulointerstitial nephritis in over 18 months of age of WBN/Kob rats. Infiltration of CD8^+ cells and deposition of tissue-specific IgG2b were observed in the injured pancreas and lacrymal glands. Furthermore, regulatory T cells (Tregs) defined as CD4^+Foxp3^+ cells decreased in the periphery of WBN/Kob rats, which suggests that the onset of these diseases is at least, attributable to the failure in the maintenance of peripheral immune tolerance. These features clearly show that WBN/Kob rats can be a useful animal model for autoimmune pancreatitis with Sjogren-like syndrome or multifocal fibrosclerosis in the human patients. We also show that these autoimmune diseases can be prevented with a newly devised strategy of bone marrow transplantation (BMT) where bone marrow cells (BMCs) are directly injected into the bone marrow cavity; intra BM BMT (IBM-BMT). These results identify the WBN/Kob rat as the first spontaneous animal model of human AIP and multifocal fibrosclerosis.In conclusion, we identified the role of regulatory T cells in the development of autoimmune pancreatitis in human and animal model. Less