Autoimmune response to M3 muscarinic acetylcholine receptor in Sjogren's syndrome

目的：探讨M3受体自身免疫反应在干燥综合征（SS）发病中的作用。方法：1）抗M3受体抗体在SS中的特异性; 2）检测SS中M3受体反应性T细胞;在来自类风湿性关节炎（RA）（N=21）、系统性红斑狼疮（SLE）（N = 21）、原发性胆汁性肝硬化（PBC）（N=84）、获得性无汗症（AA）12例。RA、SLE、PBC、AA N端抗体阳性率分别为42.9%、28.6%、90.5%、16.7%。第一环抗体阳性率分别为33.3%、28.6%、72.6%、0%，第二环抗体阳性率分别为33.3%、57.1%、76.2%、0%，第三环抗体阳性率分别为33.3%、28.6%、69.0%、0%。2)从SS（N=3）和对照（N=3）分离的PBMC用M3 R混合肽（N末端、第1、第2、第3胞外环）刺激。IFNγMACS细胞因子分泌试验在1例SS中检测到M3 R反应性IFNγ产生性CD 4 +T细胞，但在对照组中未检测到。总之，显示抗M3 R抗体不是SS特异性的，并且在SS中检测到M3 R反应性T细胞。

To clarify the pathogenic roles of autoimmune response to M3 muscarinic acetylcholine receptor (M3R) in Sjogren’s syndrome (SS)1) the disease specificity of anti-M3R antibodies in SS2) the detection of M3R reactive T cells in SS.1) Anti-M3R antibodies were examined by M3R peptides (N terminal, 1st, 2nd, 3rdextracellular loops) based ELISA in sera from rheumatoid arthritis (RA) (N=21), systemic lupus erythematosus (SLE) (N=21), primary biliary cirrhosis (PBC) (N=84), and acquired anhidrosis (AA) (N=12)Antibodies for N terminal were positive in 42.9% of RA, 28.6% of SLE, 90.5% of PBC, 16.7% of AA. Antibodies for 1stloop were positive in 33.3%, 28.6%, 72.6%, 0%, for 2ndloop, 33.3%, 57.1%, 76.2%, 0%, for 3rdloop, 33.3%, 28.6%, 69.0%, 0%, respectively. 2) PBMC isolated from SS (N=3) and controls (N=3) were stimulated with M3R mix peptides (N terminal, 1st, 2nd, 3rd extracellular loops). M3R reactive IFNγproducing CD4+T cells were detected by IFNγMACS cytokine secretion assay in one SS, but not in controls. In conclusion, it was revealed that anti-M3R antibodies were not SS-specific, and M3R reactive T cells were detected in SS.