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Wang F.-M.,Peking University | Yu F.,Peking University | Yu F.,Key Laboratory of Renal Disease | Zhao M.-H.,Key Laboratory of Renal Disease | Zhao M.-H.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment
Protein Expression and Purification

The aim of this study was to establish a method of purifying intact complement factor H (CFH) from human plasma. CFH was isolated from human plasma by polyethylene glycol (PEG) precipitation, following three sequential chromatographic columns, which consisted of l-lysine Sepharose column, Resource Q column and Sephacryl S-300 High Resolution HiPrep 16/60 column. All the above steps were performed at 4 C by Fast Protein Liquid Chromatography (FPLC) AKTA Purifier 10 with Frac-900. Identification of the purified CFH was confirmed by SDS-PAGE and Western blot. The following functions of the purified CFH were further analyzed compared with the commercial CFH in vitro: (1) binding ability with C3b; (2) binding ability with mCRP; (3) the protecting function of the hemolysis of sheep red blood cells; (4) the cofactor role for complement factor I-mediated proteolytic inactivation of C3b. Homogeneous CFH was purified from the plasma fraction through the above four steps. The purity and the functions of the purified CFH were comparable to the commercial CFH. The yield of CFH was 26 ± 3% in our study. Compared with previous methods, our method was high yield with high purity. We established a stable and feasible system for purifying intact CFH, which could be used in the lab and clinical investigations. © 2013 Elsevier Inc. All rights reserved. Source

Tan Y.,Peking University | Tan Y.,Key Laboratory of Renal Disease | Tan Y.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment | Yu F.,Peking University | And 5 more authors.
Current Opinion in Nephrology and Hypertension

PURPOSE OF REVIEW: Vascular injury is one of the typical symptoms of systemic lupus erythematosus (SLE), and may play a key role in the choice of treatment strategy and prediction of prognosis. In this review, diverse vascular lesions in SLE and their clinical significance are discussed. RECENT FINDINGS: The clinical features of vascular disease in SLE differ from organ to organ, and may be extreme with regard to renal vascular lesions. Vascular lesions in SLE may be of inflammatory or thrombotic origin, and immune system dysfunction is considered to be a predominant feature. Numerous lines of evidence suggest that the activation and injury of endothelial cells might play a key role in the pathogenesis. SUMMARY: Vascular lesions in SLE are mediated by a complex interaction between the immune system and other contributing factors. Different therapies developed for vascular lesions, both immunosuppressive and nonimmunosuppressive, should be selected based on the different clinical and pathological characteristics, and our future understanding of the different mechanisms involved. © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. Source

Yang X.-W.,Peking University | Yang X.-W.,Key Laboratory of Renal Disease | Yang X.-W.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment | Tan Y.,Peking University | And 8 more authors.
Nephrology Dialysis Transplantation

Background. Although nephritogenic autoantibodies are considered to play a central role in the initiation of lupus nephritis, whether these autoantibodies are associated with renal clinical and pathological activity or renal outcome is still controversial. Here, we investigated the associations of certain serum autoantibodies with renal disease activity and renal outcome in a large cohort of Chinese patients with lupus nephritis. Methods. One hundred and thirty-six Chinese patients with biopsy-proven lupus nephritis and with long-term follow up data were studied. Sera at renal biopsy were tested for a panel of autoantibodies, including anti-nuclear antibodies, anti-double-stranded DNA (anti-dsDNA) antibodies, anti-extractable nuclear antigen antibodies, anti-C-reactive protein antibodies, anti-C1q antibodies, anti-cardiolipin antibodies and anti-β2-glycoprotein I antibodies. Associations of these autoantibodies with clinical features, laboratory findings, histopathological data and renal outcomes were further investigated. Results. Among the various autoantibodies, anti-dsDNA and anti-C1q antibodies were better than other antibodies to evaluate the renal disease activity. Anti-dsDNA antibodies were correlated with higher incidence of leukocyturia (P< 0.05), total pathological activity index (AI) score (P< 0.05), endocapillary hypercellularity (P< 0.05), subendothelial hyaline deposits (P< 0.05) and leukocyte infiltration (P< 0.05). Anti-C1q antibodies were correlated with leukocyturia (P< 0.01), hematuria (P< 0.003) and the majority of the histopathological AIs including total AI score (P< 0.003), endocapillary hypercellularity (P< 0.003), cellular crescents (P< 0.05), karyorrhexis/fibrinoid necrosis (P< 0.003), subendothelial hyaline deposits (P< 0.003) and leukocyte infiltration (P< 0.01). Patients with both anti-dsDNA and anti-C1q antibodies had higher renal disease activity and poorer renal outcome (log-rank test: P = 0.048) compared with those without the two antibodies. In univariate survival analysis of renal prognosis, neither the presence of anti-C1q nor the presence of anti-dsDNA antibodies was a risk factor of renal survival. However, the combination of the two antibodies predicted renal prognosis (hazard ratio 4.40, 95 confidence interval: 1.26815.269, P = 0.02). Conclusions. Anti-C1q antibodies are more closely correlated with renal disease activity than the other autoantibodies. The combination of anti-C1q and anti-dsDNA autoantibodies indicates higher renal disease activity and predicts poor renal outcome. © 2012 The Author. Source

Song D.,Peking University | Song D.,Key Laboratory of Renal Disease | Song D.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment | Yu X.-j.,Peking University | And 19 more authors.
American Journal of Reproductive Immunology

Problem: Postpartum atypical hemolytic uremic syndrome (aHUS) is a life-threatening syndrome with unclear pathogenesis. The current study aimed to investigate the clinical and pathological features, complement activation status, and the genetic variations in a Chinese cohort of patients with renal biopsy-proven postpartum aHUS. Method of study: Five patients with postpartum aHUS were recruited. Renal biopsy specimens were examined and scored. Plasma levels of complements were detected, and coding sequences of complement regulators were screened. Anti-CFH/CFI autoantibodies were further detected. Results: Patients with postpartum aHUS patients presented with severe clinical manifestations and renal involvement. The renal biopsies of the five patients showed typical features of thrombotic microangiopathies. The levels of the following complement components, C4d, Bb, C3a, C5a, and SC5b-9, were significantly elevated in patients with postpartum aHUS compared with normal non-pregnant controls. The plasma levels of CFH and CFI significantly decreased in patients with postpartum aHUS compared with normal pregnant women. Three CFH single nucleotide polymorphisms (SNPs) were identified in the five patients. Two patients presented with CFH autoantibodies. Conclusion: Postpartum aHUS is a clinical syndrome with severe renal damage. Genetic deficiencies and autoantibodies of CFH may lead to alternative pathway overactivation and participated in the pathogenesis of postpartum aHUS. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source

Wang F.-M.,Peking University | Wang F.-M.,Key Laboratory of Renal Disease | Wang F.-M.,Key Laboratory of Chronic Kidney Disease Prevention and Treatment | Yu F.,Peking University | And 11 more authors.
Rheumatology (United Kingdom)

Objective: The aim of this study was to investigate serum complement factor H (CFH) and its associations with clinical and pathological features in patients with LN. Methods: Serum CFH was detected in 241 LN patients, 38 active and 11 inactive patients with SLE without clinical evidence of renal involvement and 51 normal controls. Serum CFH autoantibodies and CFH Tyr402His were screened in the 241 LN patients. CFH deposition in kidneys was detected in some patients. Results: Serum CFH levels in patients with LN at active phase were significantly lower than in 38 SLE patients or in normal controls. No serum anti-CFH autoantibodies were detected in patients with LN, and there was no significant difference in CFH Tyr402His distribution between patients with LN and normal controls. Glomerular expression of CFH was stronger than in normal controls. Serum CFH levels were mildly negatively associated with SLEDAI scores (r = -0.204, P = 0.001) and positively associated with serum C3 (r = 0.367, P < 0.001) and haemoglobulin levels (r = 0.193, P = 0.003). Patients with LN class III, subclass IV-S and those with thrombotic microangiopathy had the lowest serum CFH. Conclusion: Serum CFH levels were associated with disease activity of LN. © The Author 2012. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. Source

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