title: Serum A08 C1q antibodies are associated with disease activity and prognosis in Chinese patients with lupus nephritis.
abstract: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by overproduction of numerous autoantibodies. Many studies have sought to identify such biomarkers to distinguish patients with active lupus nephritis from SLE patients without renal involvement. Because antibodies to complement C1q appear to be prevalent in patients with active lupus nephritis, we analyzed the frequency of antigenic epitopes of C1q and their clinical significance in a large multicenter study of Chinese patients. The lupus cohort consisted of 210 patients with active lupus nephritis as a discovery cohort, 130 active patients as a validation cohort along with 130 SLE patients without clinical renal involvement, and 100 healthy controls. Serum antibodies to intact C1q, the collagen-like region, the globular head region, and the new linear A08 epitope to C1q were screened by specific ELISA. The frequency of antibodies to intact C1q, the C1q-collagen-like region, and the A08 antibodies in the discovery cohort were significantly higher than that in patients without renal involvement or healthy controls. Antibodies to the globular head region were not prevalent enough for further study. The results were confirmed in the validation cohort. The area under the curve for anti-A08 antibodies was significantly greater than those for both the intact and collagen-like region antibodies to discriminate between active lupus nephritis and active SLE without clinical renal involvement. The A08 antibodies were all negative at remission. The serum A08 antibody level correlated better with disease relapse than that of antibodies to either the intact or the collagen-like region, significantly predicting renal prognosis. Thus, serum levels of A08 C1q antibodies are closely associated with disease activity and prognosis in lupus nephritis.
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China and Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Pang
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China and Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College and Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education; Beijing, PR China.
authors.forename: Yongzhe
authors.initials: Y
authors.lastname: Li
authors.affiliation: Renal Division, Jing Dong Yu Mei Traditional Chinese Medicine and Western Medicine Integrative Kidney Disease Hospital, Hebei, PR China.
authors.forename: Jianchun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Nephrology, Anyang District Hospital, Henan, PR China.
authors.forename: Yongbing
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Nephrology, First Affiliated Hospital of Henan University of Science and Technology, Henan, PR China.
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Department of Nephrology, Beijing General Hospital of Armed Police Forces, Beijing, PR China.
authors.forename: Chengying
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China and Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, PR China; Department of Nephrology, Peking University International Hospital, Beijing, PR China. Electronic address: yufengevert1@sina.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Yu
authors.affiliation: Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China and Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, PR China; Peking-Tsinghua Center for Life Sciences, Beijing, PR China.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zhao
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002681:China; D015331:Cohort Studies; D015922:Complement C1q / Q000276:immunology*; D005260:Female; D006801:Humans; D008181:Lupus Nephritis / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D011379:Prognosis; D055815:Young Adult
chemical_list: D015922:Complement C1q
keywords: anti-c1q autoantibodies; complement; epitope; lupus nephritis; systemic lupus erythematosus