Antisignal recognition particle-positive polymyositis successfully treated with myeloablative autologous stem cell transplantation.

Patients with antisignal recognition particle (SRP)-positive myositis usually present with symmetric, progressive muscle weakness and highly elevated levels of serum creatine phosphokinase (CPK).1 A 32-year-old male patient presented with these symptoms (CPK 3601 U/l, normal range 0–190 U/l) in September 2000. Magnetic resonance imaging (MRI) of the thighs revealed a massive oedema (fig 1). After ineffective treatment with glucocorticosteroids, azathioprine, methotrexate, ciclosporine A, mycophenolate mofetil and intravenous immunoglobulins MRI assessed active myositis. The muscle biopsy revealed a necrotising myopathy. Treatment was switched to cyclophosphamide pulses with 750 mg/m2 every 3 weeks and intensified by high-dose cyclophosphamide for stem cell mobilisation with 4000 …