Rapidly progressive glomerulonephritis after introduction of certolizumab pegol: a case report.

Tumour necrosis factor (TNF) inhibitors are used against a variety of connective tissue diseases, including rheumatoid arthritis. Contrarily, although rare, TNF inhibitors are known to induce autoimmune diseases, such as systemic lupus erythematosus and psoriasis as a paradoxical reaction. We experienced a case of rapidly progressive glomerulonephritis after introduction of certolizumab pegol. The patient was a 30-year-old woman who was previously diagnosed with rheumatoid arthritis in X-8. She received treatment with methotrexate (8 mg/week) and infliximab (3 mg/kg/8 weeks), following which she showed low disease activity and remission. In September X-1, methotrexate and infliximab were discontinued and certolizumab pegol was introduced because she desired to bear children. In March X, the patient experienced renal dysfunction, and urinary protein analysis revealed positivity for myeloperoxidase anti-neutrophil cytoplasmic autoantibody. Renal biopsy showed crescentic glomerulonephritis, and the patient was diagnosed with rapidly progressive glomerulonephritis due to TNF inhibitor-induced microscopic polyangiitis. As she desired to bear children, rituximab was introduced in addition to corticosteroids, which led to remission of the symptoms. TNF inhibitors should be discontinued in patients who develop rapidly progressive glomerulonephritis, and these patients should be treated with immunosuppressive drugs, such as massive corticosteroids and cyclophosphamide. In the present case, rituximab was useful for not only the treatment, but also for the preservation of fertility.