title: Frequency of class III and IV nephritis in systemic lupus erythematosus without clinical renal involvement: an analysis of predictive measures.
abstract: OBJECTIVE
  To determine the frequency of International Society of Nephrology/Renal Pathology Society (ISN/RPS) class III or IV lupus nephritis in patients with systemic lupus erythematosus (SLE) without clinical renal involvement.
  
  
  METHODS
  We investigated the renal pathology of 195 patients with SLE, including 86 patients without clinical renal involvement.
  
  
  RESULTS
  Lupus nephritis other than class I was found in 58% of the patients without clinical renal involvement, and class III and IV nephritis was found in 15% of these patients. To reveal the predictive measures involved in class III or IV lupus nephritis, we explored the clinical measures in patients with SLE who did not have clinical renal involvement. Anti-dsDNA antibody titers were significantly higher (p = 0.0266) and C3 values were significantly lower (p = 0.0073) in patients with class III or IV lupus nephritis than in patients without class III or IV lupus nephritis. The sensitivity and specificity values were 77% and 73%, respectively, for cutoff levels of both 40 IU/ml for anti-dsDNA antibodies and 55 mg/dl for C3 (OR 8.8, p = 0.0011).
  
  
  CONCLUSIONS
  The frequency of nephritis, including ISN/RPS class III and IV, was unexpectedly high in SLE patients without clinical renal involvement. ISN/RPS class III or IV lupus nephritis could be hidden in patients with SLE who present both a high titer of anti-dsDNA antibody and a low concentration of C3, even when they have clinically normal urinary findings and renal function.
authors.affiliation: Institute of Rheumatology, Tokyo Women's Medical University, 10-22 Kawada-cho, Shinjuku-Ku, Tokyo 162-0054, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Wakasugi
authors.forename: Takahisa
authors.initials: T
authors.lastname: Gono
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Masako
authors.initials: M
authors.lastname: Hara
authors.forename: Yumi
authors.initials: Y
authors.lastname: Koseki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Katsumata
authors.forename: Masanori
authors.initials: M
authors.lastname: Hanaoka
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamanaka
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001706:Biopsy; D002648:Child; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology* / Q000503:physiopathology*; D007677:Kidney Function Tests; D008180:Lupus Erythematosus, Systemic / Q000276:immunology* / Q000473:pathology*; D008181:Lupus Nephritis / Q000145:classification* / Q000276:immunology* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D055815:Young Adult