The course and treatment of lupus nephritis.

Renal involvement by systemic lupus is variable; some patients have minimal clinical and histologic involvement, whereas others have fulminant renal failure and severe proliferative renal lesions on biopsy. The World Health Organization (WHO) classification has greatly aided in the study of lupus nephritis. This classification defines six major patterns of renal involvement, each with characteristic clinical correlates and a typical course and prognosis. Transformations from one pattern of lupus nephritis to another may occur, and there may also be prominent involvement of the tubulointerstitial compartment and vasculature. Treatment of the renal lesions may be directed at the individual class of lupus nephritis. Thus patients with mesangial involvement (WHO Class II) do not require therapy directed at their kidney lesions. Many patients with biopsies showing focal proliferative disease (WHO Class III) and all patients whose biopsies show diffuse proliferative lesions (WHO Class IV) require vigorous treatment, which has included high-dose daily and alternate-day corticosteroids, azathioprine, i.v. pulse methylprednisolone, plasmapheresis, total lymphoid irradiation, cyclosporine, and oral and i.v. cyclophosphamide. Controlled trials have yielded reasonable evidence for the safety and efficacy of some treatments, whereas others have been used only in uncontrolled studies. When used judiciously, such vigorous therapy can improve the renal survival of patients with severe lupus nephritis.