González-Cabrero J, Egido J, Sancho J, Moldenhauer F
Nephrology Service, Fundación Jiménez Díaz (Universidad Autónoma), Madrid, Spain.
Clin Exp Immunol. 1987 Jun;68(3):694-702.
Patients with IgA nephropathy often present a large array of antibodies against diet antigens and this disease can be experimentally induced by alimentary antigens. In this report, we have described the isolation from a patient with IgA nephropathy of antibovine serum albumin (BSA)-antibody idiotypes that are specifically recognized by auto-and heteroantiidiotypic antibodies. The fact that antigen (BSA) but not monomeric or aggregated human IgG inhibited the binding of antiidiotypic antibodies to the idiotypes, suggested that the idiotypic determinants are in or near the antigen binding site and that it is not a rheumatoid factor. By means of the heteroantiidiotypic antibodies raised in rabbits we observed the presence of increased levels of shared idiotypes in serum and/or immune complexes (IC) of 48 out of 70 (68.5%) genetically unrelated patients with IgA nephropathy. The close correlation (P less than 0.005) between the presence of IgA-IC, measured by Raji cell assay, and the existence of high levels of serum idiotypes, suggest that a portion of circulating IC could consist of idiotype-antiidiotype. A strong concordance between the presence and levels of idiotypes and the clinical activity, as defined by the existence of haematuria, was also noted. The discrepancies and absence of correlation observed in our study among the levels of anti-BSA antibodies of different classes and serum levels of idiotypes, circulating IC and haematuria could suggest that the antibodies reacting with the heterologous antiidiotypic antibodies could be directed to other more pathogenic antigens than dietary antigens. All together, our results suggest that IgA nephropathy might belong to the group of diseases that occur in susceptible individuals with a limited potential in the immunological response repertoire.
IgA肾病患者常常呈现出大量针对饮食抗原的抗体，并且这种疾病可通过食物抗原实验性诱发。在本报告中，我们描述了从一名IgA肾病患者中分离出抗牛血清白蛋白（BSA）抗体独特型，这些独特型能被自身和异种抗独特型抗体特异性识别。抗原（BSA）而非单体或聚合的人IgG抑制抗独特型抗体与独特型的结合，这一事实表明独特型决定簇位于抗原结合位点内或附近，且它不是类风湿因子。通过在兔体内产生的异种抗独特型抗体，我们观察到在70名无亲缘关系的IgA肾病患者中，有48名（68.5%）患者的血清和/或免疫复合物（IC）中存在共享独特型水平升高的情况。通过Raji细胞试验检测的IgA-IC的存在与血清中高水平独特型的存在之间密切相关（P小于0.005），这表明一部分循环IC可能由独特型-抗独特型组成。还注意到独特型的存在和水平与由血尿定义的临床活动之间有很强的一致性。在我们的研究中，不同类别抗BSA抗体水平与独特型血清水平、循环IC和血尿之间观察到的差异及缺乏相关性，可能表明与异种抗独特型抗体反应的抗体可能针对的是比饮食抗原更具致病性的其他抗原。总之，我们的结果表明IgA肾病可能属于在免疫反应库潜力有限的易感个体中发生的疾病类别。
