Rate nephelometry assay

The levels of blood lipids, including triglyceride (TG) (BIOSINO BIO-TECHNOLOGY&SCIENCE INC, Beijing, China; normal range: 0.56–1.7mmol/L),total cholesterol (TCHO) (BIOSINO BIO-TECHNOLOGY&SCIENCE INC, Beijing, China; normal range: 3.4–5.2mmol/L), high-density lipoprotein cholesterol (HDL-C) (SEKISUI MEDICAL TECHNOLOGY (CHINA) LTD, Beijing, China; normal range: 0.9–1.4mmol/L) and low-density lipoprotein cholesterol (LDL-C) (SEKISUI MEDICAL TECHNOLOGY (CHINA) LTD, Beijing, China; normal range: 2.1–3.1mmol/L), for all the patients were detected before the day of renal biopsy.
Serum antinuclear antibodies (ANA) were detected using indirect immunofluorescence assay (EUROIMMUN, Lübeck, Germany) and anti-double-stranded DNA antibodies were detected using Crithidia luciliae indirect immunofluorescence test (EUROIMMUN, Lübeck, Germany). Anti-extractable nuclear antigen (ENA) antibodies, including anti-Sm, anti-SSA, anti-SSB and anti-RNP antibody, were detected using immunodotting assay (EUROIMMUN, Lübeck, Germany). Anti-cardiolipin antibodies were detected using ELISA (enzyme-linked immunosorbent assay) (EUROIMMUN). Serum C3 was determined using rate nephelometry assay (Beckman-Coulter, IMMAGE, USA, normal range>0.85g/L).

An indirect immunofluorescence assay (EUROIMMUN, Lübeck, Germany) was used to detect serum antinuclear antibodies [26 (link)]. A Crithidia luciliae indirect immunofluorescence assay (EUROIMMUN, Lübeck, Germany) was used to detect anti-double-stranded DNA antibodies [26 (link)]. An enzyme-linked immunosorbent assay (ELISA) (EUROIMMUN, Lübeck, Germany) was used to detect anticardiolipin antibodies [26 (link)]. A rate nephelometry assay (IMMAGE; Beckman-Coulter, USA) was used to determine circulating C3 levels [26 (link)]. Urinary neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) were detected by commercial kits (R&D Systems, Minneapolis, MN, USA).