SLE Antibody-Secreting Cells Are Characterized by Enhanced Peripheral Maturation and Survival Programs [AIRR]. SLE Antibody-Secreting Cells Are Characterized by Enhanced Peripheral Maturation and Survival Programs [AIRR]

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by multiple autoantibodies, some of which are present in high titers in a sustained, B cell-independent fashion consistent with their generation from long-lived plasma cells (LLPC). Active SLE displays high numbers of circulating antibody-secreting cells (ASC). Understanding the mechanisms of generation and survival of SLE ASC would contribute important insight into disease pathogenesis and novel targeted therapies. We studied the properties of SLE ASC through a systematic analysis of their phenotypic, molecular, structural, and functional features. Our results indicate that in active SLE, relative to healthy post-immunization responses, blood ASC contain a much larger fraction of newly generated mature CD19-CD138+ASC similar to bone marrow (BM) LLPC. SLE ASC were characterized by morphological and structural features of premature maturation. Additionally, SLE ASC express high levels of CXCR4 and CD138, and molecular programs consistent with increased longevity based on pro-survival and attenuated pro-apoptotic pathways.Notably, SLE ASC demonstrate autocrine production of APRIL and IL-10 and experience prolonged in vitro survival. Combined, our findings indicate that SLE ASC are endowed with enhanced peripheral maturation, survival and BM homing potential suggesting that these features likely underlie BM expansion of autoreactive PC. Overall design: To investigate the question of whether different types of ASC arise from distinct B cell precursors or whether a common precursor might generate different ASC progeny through separate differentiation pathways, or instead through sequential maturation. Sorted ASC populations (Pop 2, Pop 3, Pop 4 and Pop 5) from active SLE patients were used to extract the total cellular RNA by using the RNeasy Mini Kit (Qiagen, Inc. Valencia, CA) according to the manufacturer's protocol. Approximately 400 pg of RNA was subjected to reverse transcription using the iScript RT kit. Resulting cDNA products were combined with 50 nM VH1- VH6 specific primers and 250 nM Ca, Cm, and Cg specific primers in a 25 μl PCR reaction.

系统性红斑狼疮（Systemic Lupus Erythematosus, SLE）是一种自身免疫性疾病，以多种自身抗体为特征，其中部分抗体以持续高滴度形式存在且不依赖B细胞，这与其由长寿浆细胞（long-lived plasma cells, LLPC）产生的机制相符。活动性SLE患者体内存在大量循环抗体分泌细胞（antibody-secreting cells, ASC）。阐明SLE中ASC的产生与存活机制，将为疾病发病机制研究及新型靶向治疗提供重要见解。本研究通过对SLE患者ASC的表型、分子、结构及功能特征进行系统性分析，探究了其相关特性。研究结果显示，相较于健康人群免疫接种后的应答反应，活动性SLE患者外周血ASC中，新生成的成熟CD19-CD138+ASC占比显著更高，这类细胞与骨髓（bone marrow, BM）长寿浆细胞特征相似。SLE ASC具有早熟成熟的形态学与结构学特征。此外，SLE ASC高表达CXCR4与CD138，且基于促存活通路增强、促凋亡通路减弱的分子特征，其存活能力提升。值得注意的是，SLE ASC可自分泌产生增殖诱导配体（a proliferation-inducing ligand, APRIL）和白细胞介素10（interleukin-10, IL-10），并在体外表现出延长的存活时间。综合来看，本研究结果表明，SLE ASC具有更强的外周成熟、存活及骨髓归巢潜能，提示这些特征可能是自身反应性浆细胞在骨髓中扩增的基础。总体实验设计：为探究以下科学问题——不同类型的ASC是否源自不同的B细胞前体，或是共同前体通过不同分化通路（或依次成熟）产生不同的ASC子代，我们从活动性SLE患者体内分选得到ASC群体（群体2、群体3、群体4及群体5），按照制造商说明书，使用RNeasy Mini试剂盒（Qiagen公司，美国加利福尼亚州巴伦西亚）提取总细胞RNA。取约400 pg RNA，通过iScript RT试剂盒进行逆转录。所得cDNA产物与50 nM的VH1-VH6特异性引物，以及250 nM的Ca、Cm、Cg特异性引物混合，构建25 μl的聚合酶链式反应（Polymerase Chain Reaction, PCR）反应体系。