He X, Goronzy J J, Zhong W, Xie C, Weyand C M
Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota, USA.
Mol Med. 1995 Nov;1(7):768-80.
Rheumatoid factor (RF) is a characteristic but not pathognomic feature in patients with rheumatoid arthritis (RA). It is unknown whether the repertoire of immunoglobulin genes utilized by RF+ B cells of RA patients is unique and whether RF+ B cells in normal individuals are silenced or deleted.
Clonal B cell populations were established from the peripheral blood of normal donors (127 B cell clones), RA patients (113 RF- and 60 RF+ B cell clones) and patients with primary Sjögren's syndrome (82 RF- and 47 RF+ B cell clones) by coculturing with anti-CD3-stimulated T helper cell clones. The cross-reactivity pattern of antibodies secreted by the B cell clones was determined by ELISA on a panel of antigens. The molecular structure of the IgM heavy chains was characterized by VH family-specific RT-PCR and sequencing. VH elements which correlated with RF specificity were identified. The responsiveness of B cells expressing these VH elements to T helper cell signals was compared in normal individuals and RA patients.
The majority of RF+ B cells were monospecific when specificity was tested on five antigens. RF+ B cells expressed a significantly different repertoire of VH gene segments than RF- B cells. In particular, the VH3 gene segment V3-21 was not detected in B cell clones from normals but was the most frequent VH element in RF+ B cell clones from RA patients. Most of the V3-21 sequences were in germline configuration. The correlation between RF specificity and V3-21 gene segment usage was maintained in patients with Sjögren's syndrome. V3-21 transcripts were present in peripheral blood B cells from normal individuals. VH3-21+ B cells from RA patients but not from normal donors were responsive to preactivated T helper cells. Stimulation with a bacterial superantigen could overcome the nonresponsiveness of V3-21+ B cells in normal donors and induce the secretion of RF.
RF production is correlated with the usage of the V3-21 gene segment in two distinct RF+ diseases. In patients with these diseases, V3-21+ B cells secrete antibodies with RF activity in response to activated T helper cells. V3-21+ B cells remain in a state of nonresponsiveness in normal individuals that can be broken by superantigen stimulation. The germline configuration of VH3-21+ RF+ immunoglobulins in RA patients suggests that the loss of tolerance is not an antigen-driven process.
类风湿因子（RF）是类风湿关节炎（RA）患者的一个特征性但非诊断性的特征。目前尚不清楚RA患者RF阳性B细胞所利用的免疫球蛋白基因库是否独特，以及正常个体中的RF阳性B细胞是否沉默或缺失。
通过与抗CD3刺激的T辅助细胞克隆共培养，从正常供体（127个B细胞克隆）、RA患者（113个RF阴性和60个RF阳性B细胞克隆）和原发性干燥综合征患者（82个RF阴性和47个RF阳性B细胞克隆）的外周血中建立克隆B细胞群体。通过ELISA在一组抗原上测定B细胞克隆分泌的抗体的交叉反应模式。通过VH家族特异性RT-PCR和测序对IgM重链的分子结构进行表征。鉴定与RF特异性相关的VH元件。比较正常个体和RA患者中表达这些VH元件的B细胞对T辅助细胞信号的反应性。
当在五种抗原上测试特异性时，大多数RF阳性B细胞是单特异性的。RF阳性B细胞表达的VH基因片段库与RF阴性B细胞有显著差异。特别是，VH3基因片段V3-21在正常个体的B细胞克隆中未检测到，但在RA患者的RF阳性B细胞克隆中是最常见的VH元件。大多数V3-21序列处于种系构型。在干燥综合征患者中，RF特异性与V3-21基因片段使用之间的相关性得以维持。V3-21转录本存在于正常个体的外周血B细胞中。RA患者的VH3-21阳性B细胞对预激活的T辅助细胞有反应，而正常供体的则没有。用细菌超抗原刺激可以克服正常供体中V3-21阳性B细胞的无反应性并诱导RF的分泌。
在两种不同的RF阳性疾病中，RF的产生与V3-21基因片段的使用相关。在患有这些疾病的患者中，V3-21阳性B细胞在活化的T辅助细胞的刺激下分泌具有RF活性的抗体。在正常个体中，V3-21阳性B细胞保持无反应状态，这种状态可被超抗原刺激打破。RA患者中VH3-21阳性RF阳性免疫球蛋白的种系构型表明耐受性的丧失不是一个抗原驱动的过程。
