Chen H C, Guh J Y, Chang J M, Lai Y H
Division of Nephrology, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China.
Nephron. 2001 Jul;88(3):211-7. doi: 10.1159/000045992.
IgA nephropathy (IgAN) is characterized by predominant deposition of IgA in the glomerular mesangium. Serum IgA is often elevated in patients with IgAN, and it has been postulated that it is responsible for the mesangial lesions. However, the direct effect of circulating IgA on mesangial cells is not clear.
We investigated the effects of sera and IgA which were isolated from patients with IgAN on thymidine uptake, superoxide and fibronectin production and fibronectin mRNA expression of cultured rat mesangial cells, and we compared the findings to the effects of IgA isolated from patients with non-IgA mesangial proliferative glomerulonephritis (MsPGN) and normal controls. IgA was isolated with affinity chromatography using cyanogen bromide activated Sepharose 4B coupled to sheep antihuman IgA antiserum.
Our results demonstrated that both sera and IgA from patients with IgAN dose-dependently increased mitogenesis of mesangial cells as measured by (3)H-labeled thymidine uptake. The thymidine uptake by sera and IgA isolated from patients with IgAN was significantly higher than that of sera and IgA isolated from patients with MsPGN and normal controls. Sera and IgA from patients with IgAN significantly enhanced superoxide and fibronectin production and fibronectin mRNA expression of mesangial cells. The superoxide and fibronectin production was also significantly higher as compared with patients with MsPGN and normal controls.
Our results indicate that circulating IgA isolated from patients with IgAN is different from that of patients with MsPGN and normal controls and may potentially induce oxidative injury and production of extracellular matrix of glomerular mesangial cells in IgAN.
IgA肾病（IgAN）的特征是IgA主要沉积于肾小球系膜。IgAN患者血清IgA常升高，据推测其与系膜病变有关。然而，循环IgA对系膜细胞的直接作用尚不清楚。
我们研究了从IgAN患者分离的血清和IgA对培养的大鼠系膜细胞的胸腺嘧啶核苷摄取、超氧化物和纤连蛋白产生以及纤连蛋白mRNA表达的影响，并将结果与从非IgA系膜增生性肾小球肾炎（MsPGN）患者和正常对照分离的IgA的作用进行比较。使用与羊抗人IgA抗血清偶联的溴化氰活化的琼脂糖4B通过亲和层析分离IgA。
我们的结果表明，IgAN患者的血清和IgA均以剂量依赖方式增加系膜细胞的有丝分裂，通过（3）H标记的胸腺嘧啶核苷摄取来衡量。IgAN患者分离的血清和IgA的胸腺嘧啶核苷摄取显著高于MsPGN患者和正常对照分离的血清和IgA。IgAN患者的血清和IgA显著增强系膜细胞的超氧化物和纤连蛋白产生以及纤连蛋白mRNA表达。与MsPGN患者和正常对照相比，超氧化物和纤连蛋白产生也显著更高。
我们的结果表明，从IgAN患者分离的循环IgA不同于MsPGN患者和正常对照，可能会在IgAN中潜在地诱导肾小球系膜细胞的氧化损伤和细胞外基质产生。
