Presence of circulating abnormal CD34+ progenitors in adult Langerhans cell histiocytosis.
Langerhans cell histiocytosis (LCH) is related to the proliferation of cells, which are similar to Langerhans cells (LC) but possess many abnormal characteristics. Lesions are widespread and this fact suggests that LCH cells or their precursors are present in the blood of patients. In five adult patients, we have isolated and cultured CD34+ blood progenitors of dendritic cells. We studied their phenotype by flow cytometry and their functional properties in mixed culture with heterologous lymphocytes and with autologous lymphocytes in the presence of tri-nitro-phenyl antigen (TNP). The amount of CD34+ precursors was dramatically higher than controls but a high mortality occurred during the in vitro differentiation. The phenotype of surviving cells was similar to LC phenotype (CD1a+, CD83+, Lag+) but some of them expressed CD2. These cells were able to induce T cell proliferation in mixed culture. They could not initiate primary response to TNP, except in a patient treated with thalidomide. In our hands, these CD34+ cells may be precursors of LCH cells.
Misery
L
L
Department of Dermatology and INSERM U346 'Human Skin and Immunity', Hôpital Edouard Herriot, Lyon, France. Laurent.Misery@univ-st-etienne.fr
Rougier
N
N
Crestani
B
B
Faure
M
M
Claudy
A
A
Schmitt
D
D
Vincent
C
C
D000328:Adult; D018952:Antigens, CD34 / Q000032:analysis*; D002454:Cell Differentiation; D019070:Cell Lineage; D002478:Cells, Cultured; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000473:pathology*; D006646:Histiocytosis, Langerhans-Cell / Q000097:blood / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007801:Langerhans Cells / Q000473:pathology*; D008213:Lymphocyte Activation; D008297:Male; D016176:T-Lymphocyte Subsets; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D018952:Antigens, CD34; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor