Anti-C1q antibodies may help in diagnosing a renal flare in lupus nephritis

Gabriella Moroni, Marten Trendelenburg, Nicoletta Del Papa, Silvana Quaglini, Elena Raschi, Paola Panzeri, Cinzia Testoni, Angela Tincani, Giovanni Banfi, Genesio Balestrieri, Jürg A. Schifferli, Pier Luigi Meroni, Claudio Ponticelli

Research output: Contribution to journalArticlepeer-review


It is still uncertain which, if any, immunologic parameters may help diagnose a renal flare of lupus nephritis. Anti-C1q antibody (Ab) titers have been elevated in patients with lupus with renal involvement, but little information is available on whether the titers are different in quiescent and active phases of lupus nephritis. In this study, we compared anti-C1q Ab titers with other serological test results in 48 patients with biopsy-proven lupus nephritis to assess which parameter could offer the best reliability for differentiating between quiescent and active phases of lupus nephritis. Serum C3 and C4 levels, as well as anti-double-stranded DNA, antiendothelial cell, anti-C1q, and antiphospholipid Ab titers, were evaluated in patients with quiescent renal disease (38 samples) and those with clinical evidence of renal activity (23 samples). Only anti-C1q Ab titers correlated with active renal disease in both univariate (P <0.0001) and multivariate analysis (P <0.0001), with a sensitivity of 87% and a specificity of 92%. In six patients, immunologic parameters were measured serially. In all patients, the high anti-C1q Ab titers returned to normal values after treatment-induced remission. The other serological parameters did not show a significant association with renal disease activity. In patients with biopsy-proven lupus nephritis, anti-C1q Ab titers appear to be strongly related to renal disease activity. Their measurement may be useful for confirming the diagnosis of renal flares of lupus nephritis.

Original languageEnglish
Pages (from-to)490-498
Number of pages9
JournalAmerican Journal of Kidney Diseases
Issue number3
Publication statusPublished - 2001


  • Immunologic tests
  • Renal involvement
  • Systemic lupus erythematosus (SLE)

ASJC Scopus subject areas

  • Nephrology


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