PDF(Pubmed)
Abstract：
Poststreptococcal acute kidney glomerulonephritis (PSAGN) has been seen in adults in recent years, especially in patients with type 2 diabetes mellitus, and the renal prognosis has not always been good. There have been cases of PSAGN in which complete remission was not achieved and hematuria and proteinuria persisted, leading to end-stage renal disease. Previous reports showed that the patients subjected to PSAGN have an underlying defect in regulating the alternative pathway of complement, and they identified that antibodies to the C3 convertase, C3 nephritic factors (C3NeF), are involved. C3NeF stabilizes C3 convertase, sustains C3 activation, and causes C3 glomerulonephritis (C3GN). On the other hand, factor H is a glycoprotein that suppresses the overactivation of the alternative pathway by decaying the C3 convertase. Anti-factor H (aFH) antibodies interfere with factor H and cause the same activation of the alternative pathway as C3NeF. However, a limited number of reports describe the clinical course of C3GN with aFH antibodies. We encountered a 49-year-old Japanese man with type 2 diabetes mellitus. He was referred to our hospital because of his elevated serum creatinine, proteinuria, hematuria, and developed edema on both legs. He was diagnosed as PSAGN at the first kidney biopsy, and his renal function improved and edema and hematuria disappeared, but proteinuria persisted after 5 months. He was diagnosed as C3GN at the second kidney biopsy. In our case, no C3NeF was detected. However, a high titer of aFH antibodies was detected in stored serum from the initial presentation, providing a unified diagnosis of aFH antibody-positive C3GN secondary to PSAGN. He progressed to end-stage renal disease (ESRD) and hemodialysis was started. The persistence of high levels of aFH autoantibodies may have caused C3GN secondary to PSAGN due to activating the alternative complement pathway, which eventually worsened the nephropathy and led to ESRD.
摘要：
链球菌感染后急性肾小球肾炎（PSAGN）近年来在成人中出现，尤其是2型糖尿病患者，肾脏预后并不总是好的。有PSAGN病例未能完全缓解，血尿和蛋白尿持续存在，导致终末期肾病.以前的报道表明，接受PSAGN的患者在调节补体替代途径方面存在潜在的缺陷，他们确定了C3转化酶的抗体，C3肾病因子（C3NeF），参与其中。C3NeF稳定C3转化酶，维持C3激活，并导致C3肾小球肾炎（C3GN）。另一方面,因子H是一种糖蛋白，通过衰变C3转化酶来抑制旁路途径的过度激活。抗H因子(aFH)抗体干扰H因子并引起与C3NeF相同的替代途径活化。然而,有限数量的报告描述了使用aFH抗体的C3GN的临床过程.我们遇到了一名49岁的日本2型糖尿病患者。他因为血清肌酐升高被转诊到我们医院,蛋白尿,血尿,两条腿都出现水肿.他在第一次肾活检时被诊断为PSAGN，肾功能改善，水肿和血尿消失，但5个月后仍有蛋白尿。他在第二次肾脏活检中被诊断为C3GN。在我们的案例中,未检测到C3NeF。然而,从初始呈递开始，在储存的血清中检测到高滴度的aFH抗体，为PSAGN继发aFH抗体阳性C3GN提供统一诊断。他进展为终末期肾病（ESRD），开始血液透析。高水平的aFH自身抗体的持续存在可能由于激活替代补体途径而导致PSAGN继发的C3GN，最终使肾病恶化并导致ESRD。
