Drew P A, Nieuwhof W N, Clarkson A R, Woodroffe A J
Clin Exp Immunol. 1987 Jan;67(1):124-9.
It has been postulated that IgA nephropathy (IgAGN) is caused by deposition within the glomerular mesangium of IgA polymers and IgA containing immune complexes which are overproduced in response to antigens presented at mucosal surfaces. To test this, the concentrations of specific antibodies to capsular polysaccharides from pneumococci, which are common commensal and/or pathogenic bacteria in the respiratory tract, have been measured. Sera from 35 patients with IgAGN, six with systemic lupus erythematosus (SLE), eight with membranous glomerulonephritis (MGN) and six with Goodpasture's syndrome (GPS), and from 20 controls (C) were assayed. The concentrations of IgG and IgA antibodies specific for each of five pneumococcal polysaccharides (serotypes 2, 7F, 9N, 14 and 23F) were determined by ELISA. The results from the SLE, MGN and GPS patients were pooled and used as a control group of patients with forms of nephritis other than IgAGN (patient controls, PC). Groups were compared using the Wilcoxon test or the Chi square test. There were no significant differences in the concentrations of IgG antibody to any of the serotypes between the IgAGN and normals, but the PC sera had significantly lower concentrations than either the IgAGN or normals. By contrast, there were no differences between the PC and C in the proportion with detectable IgA antibody to four of the serotypes, but this was significantly increased in IgAGN. There was insufficient IgA antibody to serotype 2 to detect in the assay system used. It is concluded that IgAGN patients have greater concentrations of IgA antibodies, but not IgG, to these pneumococcal polysaccharides, compared with normal controls or patients with other forms of nephritis.
据推测，IgA肾病（IgAGN）是由IgA聚合物和含IgA免疫复合物沉积于肾小球系膜所致，这些物质是针对黏膜表面呈现的抗原过度产生的。为验证这一点，已对肺炎球菌荚膜多糖特异性抗体的浓度进行了检测，肺炎球菌是呼吸道常见的共生菌和/或病原菌。检测了35例IgAGN患者、6例系统性红斑狼疮（SLE）患者、8例膜性肾小球肾炎（MGN）患者、6例Goodpasture综合征（GPS）患者以及20名对照者（C）的血清。通过酶联免疫吸附测定法（ELISA）测定了针对五种肺炎球菌多糖（血清型2、7F、9N、14和23F）各自的IgG和IgA抗体浓度。将SLE、MGN和GPS患者的结果合并，用作非IgAGN形式肾炎患者的对照组（患者对照，PC）。使用Wilcoxon检验或卡方检验对各组进行比较。IgAGN患者与正常对照者之间，针对任何血清型的IgG抗体浓度均无显著差异，但PC血清的浓度显著低于IgAGN患者和正常对照者。相比之下，PC组和C组中针对四种血清型可检测到IgA抗体的比例无差异，但在IgAGN组中这一比例显著增加。在所使用的检测系统中，针对血清型2的IgA抗体不足，无法检测。得出的结论是，与正常对照者或其他形式肾炎患者相比，IgAGN患者针对这些肺炎球菌多糖的IgA抗体浓度更高，但IgG抗体浓度并非如此。
