AUTHOR=Duan Suyan , Sun Lianqin , Nie Guangyan , Chen Jiajia , Zhang Chengning , Zhu Huanhuan , Huang Zhimin , Qian Jun , Zhao Xiufen , Xing Changying , Zhang Bo , Yuan Yanggang 

TITLE=Association of Glomerular Complement C4c Deposition With the Progression of Diabetic Kidney Disease in Patients With Type 2 Diabetes

JOURNAL=Frontiers in Immunology

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.02073

DOI=10.3389/fimmu.2020.02073

ISSN=1664-3224

ABSTRACT=Objectives As accumulating data supporting the potential role of the complement system in the pathogenesis of diabetic kidney disease (DKD), the present study aimed to explore the association of glomerular complement C4 deposition with the baseline clinicopathological characteristics and the prognosis of DKD in type 2 diabetes (T2DM) patients.
Methods A total of 79 T2DM patients with biopsy-proven DKD were enrolled. Clinicopathological features and renal outcomes were compared between groups divided by the glomerular C4c deposition patterns and median values of serum C4. Renal outcomes were defined by doubling of serum creatinine level or progression to end-stage renal disease (ESRD). A Cox proportional hazards model was employed to identify the risk factors associated with renal events.
Results Patients with glomerular C4c deposition had more severe renal insufficiency than those without C4c deposits, along with significantly higher levels of 24-h urinary protein, triglyceride, but lower serum albumin and interstitial inflammation score. Besides, serum C4 levels positively correlated with urinary protein and serum C3 levels. During 21.85±16.32 months of follow-up, Kaplan-Meier curve analysis showed significantly faster deterioration of renal function for patients with positive glomerular C4c deposition as well as higher levels of serum C4. More specifically, more than half of our patients with C4c deposition had C3c or C1q deposition, and patients with glomerular complement complex of C4c and one or two of C3/C1q deposition had more severe proteinuria and a higher rate of DKD progression than those with negative C4c deposits. The univariate Cox regression indicated that factors of combined serum and glomerular C4, urinary protein, serum creatinine, serum C3, combined glomerular C4c and IgM and interstitial inflammation were associated with an increased risk of DKD, but only glomerular C4c intensity (HR 1.584, 95%CI [1.001,2.508], p=0.0497), as well as baseline age and diabetic neuropathy, were independent risk factors for renal survival by the multivariate Cox analysis.
Conclusions Glomerular C4c deposition was associated with poor renal function and prognosis in T2DM patients with DKD. Glomerular C4c deposition was an independent risk factor for DKD progression.