[Treatment of lupus nephritis in children].

The severity of renal disease in systemic lupus erythematosus is variable. Renal biopsy is important to guide the treatment. The World Health Organization classification define six different histological categories with possible transformations from one category to another. Histological signs of activity or chronicity are important with respect to prognosis and treatment. Examination of renal biopsy allows predicting the reversibility of histological lesions following therapy. Apart from histological signs of severity, other factors may influence the prognosis: arterial hypertension, initial serum creatinine, the delay between onset of renal disease and treatment, the occurrence of exacerbations of the nephropathy, and the response to therapy by the end of the first year. The prognosis of severe forms of lupus nephritis, mainly diffuse proliferative glomerulonephritis, has improved during the last 20 years. The addition of immunosuppressive agents (cyclophosphamide, azathioprine) to corticosteroids is responsible for this improvement. Methylprednisolone pulses are as effective as oral high doses of prednisone during initial treatment and have fewer side effects. Many authors advocate monthly cyclophosphamide pulses over six months, sometimes followed by quarterly pulse cyclophosphamide. However, such an approach has not been proven to be more effective than an oral course of cyclophosphamide and/or azathioprine. On follow-up, steroid therapy should be slowly tapered, and close monitoring of lupus serological parameters (anti-DNA antibodies, complement), urinary protein excretion rate, urinary sediment and renal function allow one to detect exacerbations of the disease, which may require adapted therapy. While such protocols have improved the outcome, they have potential side effects. In addition to the deleterious effect of steroids on physical appearance, often badly tolerated by adolescents, immunosuppressive treatments increase the risks of severe infectious complications and the risks of cardiovascular complications in young adults.