We read with interest the article by Aarntzen et al¹ reporting the inefficacy of anti-tumour necrosis factor (TNF) α inhibitor treatment with etanercept in adult onset Still’s disease (AOSD).

We found that etanercept and also infliximab were ineffective in two patients with AOSD. Both patients were subsequently successfully treated with the monoclonal anti-CD20 antibody rituximab, targeting B cells. In both cases AOSD was diagnosed according to American College of Rheumatology criteria. Major symptoms were polyarthritis, fever, and typical skin lesions. Despite successive treatment with prednisolone and methotrexate (MTX), ciclosporin, leflunomide, cyclophosphamide po, and intravenous immunoglobulin, the patients’ AOSD remained active, with recurrent febrile episodes, rash, synovitis, a serum ferritin level of 6400 μg/l (normal ⩽200), and a mean C reactive protein level of 82 mg/l (normal …