Autologous peripheral blood stem cell transplantation in a patient with severe mixed connective tissue disease.

A 65-year old man with mixed connective tissue disease (MCTD) and severe therapy resistant polymyositis was considered for high-dose cyclophosphamide (200 mg/kg) supported by autologous stem cell transplantation (ASCT). During a 21 months follow-up there has been a significant subjective, but objectively only a slight improvement in muscle strength. Initially the levels of serum creatine kinase and serum aldolase normalised, but are at 21 months at about the same level as before ASCT. Based on histopathological examination there is still active myositis. Our case would suggests that this treatment may have some efficacy in MCTD with severe polymyositis although longer follow-up is needed.