Harats N, Rubinow A, Fischel R, Eilat D
Department of Medicine A, Hadassah University Hospital, Jerusalem, Israel.
Br J Rheumatol. 1989 Jun;28(3):227-32. doi: 10.1093/rheumatology/28.3.227.
There are inherent technical difficulties in measuring IgG rheumatoid factor (IgG-RF) in the serum of patients with rheumatoid arthritis (RA). These arise from measuring a reaction between two IgG molecules and the interference of IgM-RF in the reaction. We compared the prevalence of IgG-RF in whole sera and purified IgG fractions from 58 RA patients (43 of whom were latex or sheep cell agglutination positive). Methods of purification were: ammonium sulphate precipitation and DEAE cellulose or protein A-Sepharose chromatography. IgG-RF was measured by two methods: (1) radioimmunoassay and ELISA with a monoclonal myeloma IgG (IgG4,K) as the antigen and radiolabelled rabbit anti-human IgG (previously absorbed on a column with IgG4,K) as the second antibody; (2) ELISA using rabbit IgG as the antigen and a peroxidase conjugated goat anti-human IgG as the second antibody. When whole sera were assayed, 18 (31%) contained IgG-RF. In contrast, only three of the IgG fractions (5%) were positive for IgG-RF by all methods, while the remainder were uniformly negative. These results suggest that IgG-RF determination in whole sera does not accurately reflect IgG-RF activity.
在类风湿性关节炎（RA）患者血清中测量IgG类风湿因子（IgG - RF）存在一些固有的技术难题。这些难题源于测量两个IgG分子之间的反应以及IgM - RF在该反应中的干扰。我们比较了58例RA患者（其中43例乳胶或绵羊细胞凝集试验呈阳性）全血清和纯化IgG组分中IgG - RF的患病率。纯化方法有：硫酸铵沉淀法以及DEAE纤维素或蛋白A - 琼脂糖层析法。通过两种方法测量IgG - RF：（1）以单克隆骨髓瘤IgG（IgG4，K）作为抗原，用放射性标记的兔抗人IgG（先前已在IgG4，K柱上吸附）作为二抗的放射免疫测定法和酶联免疫吸附测定法；（2）以兔IgG作为抗原，用过氧化物酶偶联的山羊抗人IgG作为二抗的酶联免疫吸附测定法。当检测全血清时，18份（31%）含有IgG - RF。相比之下，所有方法检测的IgG组分中只有3份（5%）IgG - RF呈阳性，其余均为阴性。这些结果表明，在全血清中测定IgG - RF并不能准确反映IgG - RF活性。
