No lupus nephritis in the absence of antiC1q autoantibodies?

One of the characteristics of systemic lupus erythematosus (SLE) is the large interand intra-individual variability of the clinical course. Lupus nephritis is no exception. Some patients with kidney involvement may show rapid progression to renal failure, while others may enter complete and stable remission after adequate therapy. More difficult to manage are the large number of patients who have similar clinical and histological patterns at presentation, but alternate periods of clinical quiescence with renal relapses of different severity. It is still uncertain which, if any, immunologic parameters may help to diagnose a renal flare. The increase in anti double-stranded DNA (dsDNA) titre or hypocomplementaemia related to classical pathway activation provides no indication as to whether a relapse includes the kidney. Here we review the evidence, which has accumulated over the last few years and appears to indicate that antiC1q autoantibodies (antiC1q Ab) may help in distinguishing a renal from a non-renal relapse under certain circumstances.