Lupus nephritis flares.

The clinical course of lupus nephritis varies remarkably among SLE patients, even between those with the same histological type. Current immunosuppressive agents induce remission in the majority of the patients with proliferative lupus nephritis, but a substantial proportion of them - ranging in different studies from 27% to 66% - will flare. Flares represent a significant problem because of the potential for cumulative damage that may lead to deterioration of renal function as well as toxicity due to the additional immunosuppression. Maintenance therapy with azathioprine, mycophenolate mofetil or quarterly pulses of cyclophosphamide is usually recommended. Renal flares can be characterized as nephritic or nephrotic and can be mild or severe. The majority of the patients that flare restore renal function, if diagnosed early and treated promptly. However, current immunosuppressive agents have limitations concerning efficacy and toxicity profiles. Unresolved management issues include the value of repeat renal biopsy and issues related to optimal strategy/regimen to prevent flares. Renal flares are an important feature of the natural history of lupus nephritis and provide an opportunity for additional preventive strategies, as well as measures of efficacy in future therapeutic trials.