Sinico R A, Fornasieri A, Maldifassi P, Colasanti G, D'Amico G
Department of Nephrology, San Carlo Borromeo General Hospital, Milano, Italy.
Clin Nephrol. 1988 Oct;30(4):182-6.
IgA rheumatoid factor, IgA and IgG immune complexes were measured in 119 patients with IgA nephropathy. IgA rheumatoid factor was detected in 62/119 (52%) patients and in 92/265 (35%) serum samples. There was a good correlation (p less than 0.001) between the presence of IgA rheumatoid factor and the presence as well as levels of IgG immune complexes, but not between levels of IgA rheumatoid factor and other clinical or immunological parameters. However, higher levels of serum IgA were found in the subgroup of patients with constantly positive IgA rheumatoid factor. Using aggregated human IgG, we could not demonstrate antiglobulin activity in renal biopsy specimens from 36 patients. These results suggest that IgA rheumatoid factor does not play a primary role in renal damage in IgA nephropathy, but could simply reflect a response to IgG immune complexes in a disorder characterized by abnormalities of IgA production. Nevertheless, the presence of circulating IgA rheumatoid factor in a substantial proportion of patients, especially in those with features of polyclonal IgA activation, provides additional evidence for a general perturbation of IgA metabolism in this disease and could represent an antigen-specific system with which to study regulation of IgA synthesis.
对119例IgA肾病患者检测了IgA类风湿因子、IgA和IgG免疫复合物。在62/119（52%）例患者及92/265（35%）份血清样本中检测到IgA类风湿因子。IgA类风湿因子的存在与IgG免疫复合物的存在及水平之间存在良好相关性（p<0.001），但IgA类风湿因子水平与其他临床或免疫学参数之间无相关性。然而，IgA类风湿因子持续阳性的患者亚组血清IgA水平较高。使用聚合人IgG，我们未能在36例患者的肾活检标本中证实抗球蛋白活性。这些结果表明，IgA类风湿因子在IgA肾病的肾损伤中不发挥主要作用，而可能只是反映了在以IgA产生异常为特征的疾病中对IgG免疫复合物的反应。然而，相当一部分患者中存在循环IgA类风湿因子，尤其是那些具有多克隆IgA激活特征的患者，这为该疾病中IgA代谢的普遍紊乱提供了额外证据，并且可能代表一个用于研究IgA合成调节的抗原特异性系统。
