2007 Volume 21 Issue 5-6 Pages 281-288
Langerhans cell histiocytosis (LCH) is a rare disease and its clinical manifestations vary from single system disease to severe and sometimes life-threatening multisystem disease (MS-LCH). Multi-agent chemotherapy is indicated for patients with multisystem involvement. Results of previous studies revealed that 1) under 2 yearsof age, 2) multiorgan involvement, especially in case of a high-risk organ such as bone marrow, liver/spleen and lung, or 3) poor responder to therapy at 6 weeks, were the predictors of poor prognosis. Current salvage protocols include 2-chlorodeoxyadenosine/cytarabine and allogeneic hematopoietic stem cell transplantation (HSCT). Twenty-nine patients with infantile LCH, who received HSCT during 1992 and 2003, and additional 10 patients who received reduced intensity hematopoietic stem cell transplantation (RIST) were reviewed in this article. Despite the mixed chimerism after RIST, long-term remission of LCH was achieved in several patients. It could be presumed that not an eradication of the pathologic cell clone, but rather a strong immunomodulating influence, probably mainly exerted by allogeneic T-cells (graft versus LCH effect), plays a role. The approach of less-toxic RIST with antibodies to the CD52, TNF-α and CD1a will be promising for the patients with progressive or refractory LCH in the near future.
