Studies on Autoantibody Idiotype (Id) in Autoimmune Diseases and Its Clinical Application

研究自身抗体独特型(ID)对于阐明自身抗体产生和抑制的机制具有重要意义。类风湿因子(RF)是许多自身免疫性疾病中最常见的自身抗体。我们用细胞杂交技术制备了干燥综合征(SS)患者的3个单抗RF(Ig M-K、Ig A-L和Ig A-K)和1个Waldenstrom‘s巨球蛋白血症患者的单抗RF(Ig M-K)的抗ID抗体(Ma-ID)。这些mA-ID是针对RFS的部位特异性抗体。经Western印迹分析，鉴定了其kappa链(2-IgM-K)、Mu、kappa和α(？)链(Ig A-L)和Mu-α-kappa链(Ig A-K)。一种针对IgA-K RF的MA-ID在增殖的淋巴样细胞中检测到小的核RNPs。用斑点免疫印迹法和琼脂糖凝胶电泳法检测了50份M蛋白和50份含多克隆RF的血清中的交叉反应ID(CRI)，发现40-90%的7份单抗RF、10份M蛋白和10份冷球蛋白存在交叉反应ID(CRI)。部分无RF活性的M蛋白、少数含多克隆RFs的血清和一些正常血清显示CRI。这些结果表明，在患者和正常人中存在一个或多个共有的RF V基因家族，这些基因家族在SS等自身免疫性疾病中高度表达。免疫荧光法检测外周血淋巴细胞表面免疫球蛋白(SMID)和单核细胞免疫球蛋白(SMIG)。4例单克隆性RF SS患者PBL中检测到携带SMID的B细胞(0.3%~11.8%)。3例患者经脉宽调制刺激后，B细胞分化为含胞浆ID的浆细胞。这些结果表明，在RF患者的PBL中存在单克隆性B细胞，并在体内通过一定的刺激分化为浆细胞，可能有某种调控机制刺激或抑制这些单克隆性B细胞的分化。

It is important to study autoantibody idiotype (Id) to clarify the mechanism of autoantibody production and suppression. Rheumatoid factor (RF) is a most common autoantibody seen in many autoimmune diseases. We produced monoclonal anti-Id antisera (mA-Id) by the cell hybridization technique against 3 monoclonal RFs (IgM-K, IgA-L and IgA-K) in patients with Sjogren's syndrome (SS) and one monoclonal RF (IgM-K) in a patient with Waldenstrom's macroglobulinemia. These mA-Id were site-specific antibodies against RFs. The Id determinant was studied by Western blot analysis and identified on the kappa chain (2 IgM-K), mu, kappa and alpha (?) chain (IgA-L) and mu and alpha-kappa chain (IgA-K), respectively. One mA-Id against IgA-K RF detected small nuclear RNPs in the proliferating lymphoid cells. Cross-reactive Id (CRI) was examined among 50 M proteins and 50 sera containing polyclonal RFs by dot and agar gel electrophoresis immunoblot analyses; CRI was found in 40-90% of 7 monoclonal RFs, 10 M proteins and 10 cryoglobulins in SS patients. Some M proteins without RF activity, a few of sera containing polyclonal RFs and even some normal sera showed CRI. These results suggest that there is a RF V gene family or families shared in common in patients and normal persons and these are highly expressed in autoimmune diseases such as SS. Cell surface Id (SmId) and SmIg of peripheral blood lymphocyts (PBL) were examined by the double immunofluorescence method. B cells bearing SmId (0.3-11.8%) were identified in PBL of 4 SS patients with monoclonal RF. B cell differentiation to plasma cells containing cytoplasmic Id was observed in 3 patients by PWM stimulation. These results indicate that monoclonal B cells are pressent in PBL of patients with RF and differentiate to plasma cells in vivo by some stimulations and there might be some controlling mechanism to stimulate or suppress the differentiation of these monoclonal B cells.