Camussi G, Stratta P, Mazzucco G, Gaido M, Tetta C, Castello R, Rotunno M, Vercellone A
Clin Nephrol. 1985 Mar;23(3):134-41.
Deposits of C3 but not of C1q and C4 were detected on the proximal tubules of kidneys from nephrotic patients with non-selective proteinuria. The incidence of tubular C3 deposits was significantly higher in patients with membranous glomerulonephritis, focal glomerulosclerosis, membrano-proliferative glomerulonephritis and non-selective proteinuria than in patients with minimal change disease, nephrotic syndrome and selective proteinuria or in patients with glomerular disease, but without nephrotic syndrome. The occurrence of tubular C3 deposits was positively correlated with the amount of urinary C3 excretion. In vitro studies showed that the human normal kidney as well as pathologic specimens negative for in vivo tubular C3 deposits were able to bind C3 on the brush border of proximal tubules when incubated with fresh heterologous serum. In contrast, in patients with non-selective proteinuria and in vivo tubular C3 deposits, the binding of heterologous C3 to the brush border of proximal tubules was markedly reduced. The positive correlation between the occurrence of tubular C3 deposits and the urinary complement excretion, together with the detection of the C3 breakdown products in the urines further supported the hypothesis that complement components, once filtrated through the glomerular barrier, might be activated by the brush border of the proximal tubule.
在非选择性蛋白尿的肾病患者的肾脏近端小管中检测到C3沉积，但未检测到C1q和C4沉积。膜性肾小球肾炎、局灶性肾小球硬化、膜增生性肾小球肾炎和非选择性蛋白尿患者的肾小管C3沉积发生率显著高于微小病变病、肾病综合征和选择性蛋白尿患者或无肾病综合征的肾小球疾病患者。肾小管C3沉积的发生与尿C3排泄量呈正相关。体外研究表明，人正常肾脏以及体内肾小管C3沉积阴性的病理标本在与新鲜异源血清孵育时能够在近端小管刷状缘结合C3。相反，在非选择性蛋白尿和体内有肾小管C3沉积的患者中，异源C3与近端小管刷状缘的结合明显减少。肾小管C3沉积的发生与尿补体排泄之间的正相关，以及尿中C3裂解产物的检测进一步支持了这样的假设，即补体成分一旦通过肾小球屏障滤过，可能会被近端小管的刷状缘激活。
