Treatment of Refractory Langerhans Cell Histiocytosis (LCH) With a Combination of 2-Chlorodeoxyadenosine and Cytosine Arabinoside

The combination of 2-chlorodeoxyadenosine (2-CDA) and cytosine arabino-side (Ara-C) has been shown to be effective ill children with refractory Langerhans cell histiocytosis (LCH) We have treated 5 patients with recurrent LCH with 2-CDA/Ara-C chemotherapy and closely followed immune and hematopoietic function. These patients display a decline in the absolute CD4, CDS. and natural killer cell number, decrease in the CD4/CD8 ratio. Septic events. including pneumocystis Infection were present after most of-the treatment courses (15/21). These data suggest that 2-CDA Ara-C. should be considered in resistant and relapsed pediatric patients with LCH with high-risk multiorgan involvement. Consequent profound prolonged combined immune deficiency and myelosupression should he anticipated.