IgA肾病（IgAN）以肾脏IgA沉积及血中IgA水平增高为主要特点，但IgA来源仍不清楚。我们前期发现IgAN扁桃体IgA与血清及肾脏IgA相关；同时首次发现IgAN扁桃体生发中心滤泡树突细胞（FDC）大量表达胸腺基质淋巴细胞生成素（TSLP），后者与扁桃体IgA生成显著正相关。研究证实FDC可调节B细胞IgA类别转换进而影响IgA生成。由此，我们推测：“IgAN扁桃体内高表达的TSLP通过与FDC作用促进IgA类别转换及生成，引起IgAN的发生发展”。我们拟分析TSLP、IgA类别转换调节因子（AID、BAFF等）与扁桃体、血清、肾脏IgA及肾脏病理分级间的关系。同时在扁桃体生发中心细胞中抑制和诱导TSLP的表达，检测IgA类别转换及IgA生成情况，进而探讨TSLP促进扁桃体IgA生成机制。本研究有助于阐明扁桃体TSLP在IgAN发病机制中的作用，为IgAN扁桃体切除治疗提供理论依据。

IgA nephropathy (IgAN) is characterized by an abnormally high level of IgA in the blood and a severe deposition of IgA in the renal mesangium. However, the origin of the IgA remains unclear. Our previous research indicates that the expression level of IgA is significantly increased in the tonsil of IgAN patients, and the upregulated expression of IgA in the tonsil is mainly IgA1, which correlates with serum IgA level and IgA deposited in the renal mesangium. Moreover, the expression of thymic stromal lymphopoietin (TSLP) is significantly up-regulated in the tonsil in IgAN patients, compared with that in non-IgAN, which correlates with enhanced IgA class switching and production detected in the tonsillar germinal center, mainly consisted of follicular dendritic cells (FDCs). FDCs can promote IgA class switching and IgA production. Together, we hypothesize that TSLP on FDC promotes IgA switching and IgA production in the tonsillar germinal center, leading to IgA deposition in the kidney and followed IgA nephropathy. In the present proposed research, we will investigate the effect TSLP on IgA conversion and production in the tonsil, and followed effects on IgAN occurrence. The research will be conducted in IgAN patients at different levels, including examinations on the tonsil, serum, renal tissue, and tonsillar germinal center FDC-associated cluster. The proposed study will shed light on the origin of IgA deposited in the renal mesangium, promoting the prognosis, as well as it may highlight tonsillectomy as a potential treatment for IgAN.