Shingu M, Ezaki I, Nobunaga M
Department of Internal Medicine, Kyushu University, Beppu, Japan.
Rheumatol Int. 1988;8(3):95-100. doi: 10.1007/BF00272429.
The effect of rheumatoid factor (RF) on complement-activating capacity of aggregated IgG was investigated. The degree of complement activation induced by the addition of specific amounts of aggregated IgG to patients' sera and normal sera was demonstrated by the inhibition of hemolytic activity (%IHA). The %IHA was significantly lower in rheumatoid arthritis (RA) sera and higher in systemic lupus erythematosus (SLE) sera, compared with normal sera. There was a negative correlation between %IHA and IgMRF/IgGRF ratio in RA and SLE sera, and RA synovial fluid. The %IHA and IgGRF were positively correlated in RA sera. The IgMRF/IgGRF ratio was significantly lower in SLE sera than in RA sera and systemic sclerosis sera, and was significantly lower in RA synovial fluid than in osteoarthritis synovial fluid. Isolated RF, consisting of mostly IgMRF class, inhibited complement-activating properties of aggregated IgG, depending on the concentration of RF. Isolated RF was further purified by the fractionation using high pressure liquid chromatography, and IgGRF and IgMRF were obtained. IgMRF significantly suppressed the complement-activating capacity of aggregated IgG, whereas IgGRF promoted it. These observations suggest that IgMRF acts protectively, while IgGRF induces inflammation. Thus, the expression of the biological activity of RF with special reference to immune complex interaction mainly depends on the IgMRF/IgGRF ratio.
研究了类风湿因子（RF）对聚集IgG补体激活能力的影响。通过溶血活性抑制率（%IHA）来证明向患者血清和正常血清中添加特定量的聚集IgG所诱导的补体激活程度。与正常血清相比，类风湿关节炎（RA）血清中的%IHA显著降低，而系统性红斑狼疮（SLE）血清中的%IHA则较高。在RA和SLE血清以及RA滑液中，%IHA与IgM RF/I gG RF比值呈负相关。在RA血清中，%IHA与IgG RF呈正相关。SLE血清中的IgM RF/I gG RF比值显著低于RA血清和系统性硬化症血清，RA滑液中的该比值显著低于骨关节炎滑液。主要由IgM RF类组成的分离RF可抑制聚集IgG的补体激活特性，这取决于RF的浓度。通过高压液相色谱分级分离进一步纯化分离的RF，得到IgG RF和IgM RF。IgM RF显著抑制聚集IgG的补体激活能力，而IgG RF则促进其激活。这些观察结果表明，IgM RF起保护作用，而IgG RF诱导炎症。因此，RF生物活性的表达，特别是与免疫复合物相互作用相关的表达，主要取决于IgM RF/I gG RF比值。
