Aberrant chemokine receptor expression and chemokine production by Langerhans cells underlies the pathogenesis of Langerhans cell histiocytosis.
Langerhans cell histiocytosis (LCH) is characterized by a clonal proliferation and retention of cells with a Langerhans cell (LC)-like phenotype at various sites within the body. The present study set out to elucidate whether aberrant expression of chemokine receptors or dysregulation of chemokine production in LCH lesions could explain abnormal retention of these cells. Immunohistochemical analysis on 13 LCH biopsies of bone, skin, and lymph node all expressed the immature dendritic cell (DC) marker CCR6 on the lesional LCs and absence of the mature DC marker CCR7. Furthermore, regardless of the tissue site, LCH lesions markedly overexpressed CCL20/MIP-3alpha, the ligand for CCR6. The lesional LCs appeared to be the source of this CCL20/MIP-3alpha production as well as other inflammatory chemokines such as CCL5/RANTES and CXCL11/I-TAC. These may explain the recruitment of eosinophils and CD4+CD45RO+ T cells commonly found in LCH lesions. The findings of this study emphasize that, despite abundant TNF-alpha, lesional LCs remain in an immature state and are induced to produce chemokines, which via autocrine and paracrine mechanisms cause not only the retention of the lesional LCs but also the recruitment and retention of other lesional cells. We postulate that the lesional LCs themselves control the persistence and progression of LCH.
Leiden University Medical Center, Department of Pediatrics, Division of Immunology, Hematology, Oncology, BMT and Autoimmune Diseases, PO Box 9600, 2300 RC Leiden, Netherlands.
Nicola E
NE
Annels
Cristiana E T
CE
Da Costa
Frans A
FA
Prins
Annemieke
A
Willemze
Pancras C W
PC
Hogendoorn
R Maarten
RM
Egeler
D000818:Animals; D018949:Antigens, CD1 / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology; D054418:Chemokine CCL20; D054371:Chemokine CXCL11; D018925:Chemokines / Q000096:biosynthesis*; D019742:Chemokines, CC / Q000032:analysis; D019743:Chemokines, CXC / Q000032:analysis; D006646:Histiocytosis, Langerhans-Cell / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007801:Langerhans Cells / Q000276:immunology*; D019402:Macrophage Inflammatory Proteins / Q000032:analysis; D051379:Mice; D011817:Rabbits; D054399:Receptors, CCR6; D019707:Receptors, Chemokine / Q000032:analysis*
D018949:Antigens, CD1; C108355:CCL20 protein, human; C106311:CCR6 protein, human; C419393:CD1a antigen; C515202:CXCL11 protein, human; D054418:Chemokine CCL20; D054371:Chemokine CXCL11; D018925:Chemokines; D019742:Chemokines, CC; D019743:Chemokines, CXC; C515203:Cxcl11 protein, mouse; D019402:Macrophage Inflammatory Proteins; D054399:Receptors, CCR6; D019707:Receptors, Chemokine