title: Monocyte chemoattractant-1 as a urinary biomarker for the diagnosis of activity of lupus nephritis in Brazilian patients.
abstract: OBJECTIVE
  Monocyte chemotactic protein (MCP-1), involved in the pathogenesis of lupus nephritis (LN), has recently been indicated as a new biomarker of kidney activity in systemic lupus erythematosus (SLE). Our aim was to assess urinary MCP-1 (uMCP-1) as a biomarker of renal activity in patients with SLE and to compare it to other disease activity markers, using the ELISA.
  
  
  METHODS
  Seventy-five female Brazilian patients with SLE and a control group participated in our study. Patients with SLE were distributed among 3 groups according to kidney involvement and classified according to disease activity based on clinical and laboratory measures such as urinary sediment, proteinuria, kidney function, C3, C4, anti-dsDNA, disease activity index, and renal SLE disease activity index. The serum and uMCP-1 concentrations were measured by sandwich ELISA.
  
  
  RESULTS
  In the A-LN group (active lupus nephritis: SLE with kidney involvement), the concentration of uMCP-1 was significantly higher than in other groups. A cutoff point was established using the results of the control group to apply this test in the detection of LN. A-LN had a higher frequency of positive results for uMCP-1 in comparison to the other groups (p < 0.001). To detect disease activity in patients with LN, a new cutoff was determined based on the results of patients with SLE with kidney involvement. Setting specificity at 90%, the sensitivity of the test was 50%.
  
  
  CONCLUSIONS
  The high specificity makes uMCP-1 a useful test as a predictor of kidney activity in SLE, especially when associated to other measures used in clinical practice.
authors.affiliation: Department of Rheumatology, and the Department of Immunology, Servidor Publico Estadual Hospital, São Paulo, Brazil. renatafrosa@hotmail.com
authors.forename: Renata Ferreira
authors.initials: RF
authors.lastname: Rosa
authors.forename: Kioko
authors.initials: K
authors.lastname: Takei
authors.forename: Nafice C
authors.initials: NC
authors.lastname: Araújo
authors.forename: Sônia M A
authors.initials: SM
authors.lastname: Loduca
authors.forename: José C M
authors.initials: JC
authors.lastname: Szajubok
authors.forename: Wiliam H
authors.initials: WH
authors.lastname: Chahade
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000652:urine; D001938:Brazil; D018932:Chemokine CCL2 / Q000652:urine*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008181:Lupus Nephritis / Q000175:diagnosis* / Q000503:physiopathology / Q000652:urine; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D018932:Chemokine CCL2