Fatal pulmonary fibrosis after rituximab administration.

Idiopathic nephrotic syndrome is the most frequent glomerular disease during childhood. Although immunosuppressive agents are usually effective, some severe cases remain difficult to treat. We describe a female patient with secondary steroid-resistant nephrotic syndrome who no longer responded to conventional treatment. Owing to cyclosporine toxicity, rituximab was administered. Three days after treatment the patient's clinical condition dramatically worsened and she developed acute respiratory distress. Despite all means used to treat her, she died 5 weeks after rituximab infusion. A pulmonary biopsy showed extensive fibrosis, while the alveolar epithelium was no longer visible.