Successful treatment of refractory Langerhans cell histiocytosis by allogeneic peripheral blood stem cell transplantation.

We describe a six-yr-old boy who exhibited typical signs and symptoms of LCH with EBV-associated hemophagocytic syndrome from the age of 15 months. Multiple courses of conventional chemotherapy achieved only marginal improvement over the ensuring five yr. During this period, this boy experienced recurrent episodes of hemophagocytic syndrome associated with CMV infection. Five yr after the first diagnosis of LCH, the patient was treated with allogeneic PBSCT from his HLA-identical eight-yr-old brother. PBSCT was performed using a TBI-incorporating conditioning regimen comprising TBI, busulfan, and cyclophosphamide. Diabetes insipidus, typically a permanent consequence of LCH, was well controlled by DDAVP therapy. At the time of writing, this boy is alive and well, and had been disease-free for more than two yr after the PBSCT.