Get access

Anti-C1q Autoantibodies in Lupus Nephritis


Address for correspondence: Dr. R. A. Sinico, Clinical Immunology Unit and Renal Unit, Department of Medicine, Azienda Ospedaliera Ospedale San Carlo Borromeo, Via Pio Secondo, 3 – 20153 Milano, Italy. Voice: +39.02.40222489/2343; fax: +39.02.40222222.


Anti-C1q antibodies are found in a variety of diseases, in addition to systemic lupus erythematosus (SLE), and in 3–5% of normal individuals. In particular, anti-C1q antibodies are detected at a high titer in 100% of patients with hypocomplementemic urticarial vasculitis and in 30–48% of SLE patients. Their titer correlates with active renal disease with a sensitivity of 44–100% and a specificity of 70–92%. An increase in anti-C1q antibody titer has been suggested to be able to predict renal flares in lupus nephritis so that monitoring anti-C1q might be valuable for the clinical management of SLE patients as a noninvasive biological marker. Recently our group studied 228 patients affected by lupus nephritis and found that the association of anti-C1q, C3, and C4, in a multivariate analysis, provided the best prediction of renal flares, particularly in patients with focal and diffuse proliferative lupus nephritis and in the absence of antiphospholipid antibodies.

Get access to the full text of this article