Berggren Olof, Hagberg Niklas, Alexsson Andrei, Weber Gert, Rönnblom Lars, Eloranta Maija-Leena
Department of Medical Sciences, Rheumatology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
Department of Molecular Structural Biology, Institute of Biochemistry, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany.
PLoS One. 2017 Aug 28;12(8):e0183946. doi: 10.1371/journal.pone.0183946. eCollection 2017.
Hyperactive B cells and a continuous interferon (IFN)-α production by plasmacytoid dendritic cells (pDCs) play a key role in systemic lupus erythematosus (SLE). We asked whether the interaction between B cells and pDCs stimulated with RNA-containing immune complexes affects peripheral B cell subsets.
B cells and pDCs were isolated from blood of healthy individuals and stimulated with immune complexes consisting of SLE-IgG and U1snRNP (RNA-IC). Expression of cell surface molecules as well as IL-6 and IL-10 production were determined by flow cytometry and immunoassays. Gene expression profiles were determined by a NanoString nCounter expression array.
We found a remarkable increase of double negative CD27-IgD- B cells, from 7% within fresh CD19+ B cells to 37% in the RNA-IC-stimulated co-cultures of B cells and pDCs, comparable to the frequency of double negative B cells in SLE patients. Gene expression analysis of the double negative CD27-IgD- and the CD27+IgD- memory B cells revealed that twenty-one genes were differentially expressed between the two B cell subsets (≥ 2-fold, p<0.001). The, IL21R, IL4R, CCL4, CCL3, CD83 and the IKAROS Family Zinc Finger 2 (IKZ2) showed higher expression in the double negative CD27-IgD- B cells.
The interactions between B cells and pDCs together with RNA-containing IC led to an expansion of B cells with similar phenotype as seen in SLE, suggesting that the pDC-B cell crosstalk contributes to the autoimmune feed-forward loop in SLE.
活跃的B细胞以及浆细胞样树突状细胞（pDC）持续产生干扰素（IFN）-α在系统性红斑狼疮（SLE）中起关键作用。我们研究了含RNA的免疫复合物刺激的B细胞与pDC之间的相互作用是否会影响外周B细胞亚群。
从健康个体血液中分离出B细胞和pDC，并用由SLE-IgG和U1snRNP组成的免疫复合物（RNA-IC）进行刺激。通过流式细胞术和免疫测定法测定细胞表面分子的表达以及IL-6和IL-10的产生。通过NanoString nCounter表达阵列测定基因表达谱。
我们发现双阴性CD27-IgD- B细胞显著增加，从新鲜CD19 + B细胞中的7%增加到B细胞与pDC的RNA-IC刺激共培养物中的37%，与SLE患者双阴性B细胞的频率相当。对双阴性CD27-IgD-和CD27 + IgD-记忆B细胞的基因表达分析表明，两个B细胞亚群之间有21个基因差异表达（≥2倍，p<0.001）。IL21R、IL4R、CCL4、CCL3、CD83和IKAROS家族锌指2（IKZ2）在双阴性CD27-IgD- B细胞中表达较高。
B细胞与pDC之间的相互作用以及含RNA的IC导致了具有与SLE中所见相似表型的B细胞扩增，提示pDC-B细胞串扰促成了SLE中的自身免疫前馈循环。
