Background: Langerhans cell histiocytosis (LCH) is granulomatous proliferative disorder characterized by the presence of activated Langerhans cells admixed with macrophages, lymphocytes, and eosinophils. In an effort to obtain an LCH ex vivo model, we succeeded in establishing the DOR-1 cell line from an LCH lesion of bone in a 3-year-old girl.
Procedure: The DOR-1 cell line was established from a CD1a immunoreactive LCH lesion of bone maintained in long-term cell culture. The phenotypic characteristics were assessed by immuno-cytochemistry and fluorescence activated cell sorter (FACS) analysis. Cytogenetic analysis was performed by RHG-banding that was supplemented by fluorescence in situ hybridization (FISH).
Results: The DOR-1 cells grew in vitro as a poorly differentiated mesenchymal-like cells with a doubling time between 72 and 96 hr. The cells exhibited pleomorphism and consistent immuno-reactivity for CD10 (50%), CD13 (55%), CD68 (65%), and CD117 (70%) while CD1a, Langerin and HLA-DR were not detected. By RHG-banding, several aberrant chromosomes were detected including the t (9; 17) (p23; p13) translocation and a pair of long dicentric marker chromosomes indicating clonal abnormality. Functionally, exposure to 33 nM 12-O-tetradecanoyl phorbol mirystate-13-acetate (TPA) induced DOR-1 cell differentiation with appearance of cytoplasmic extensions.
Conclusions: The DOR-1 cell line exhibits distinct immuno-cytochemical features and carries the t (9; 17) (p23; p13) translocation suggesting involvement of stromal-like cell lineage in LCH initiation and progression.