Chemokine Receptor 7 (CCR7) Participates in the Migration of DCs and Has Impact on the Progression of Primary Pterygium

Abstract

Background: The effect of chemokine receptors and their ligands for dendritic cells (DCs) plays a critical role in the immune response, but whether chemokine receptor 7 (CCR7) has an impact on DCs migrating in pterygia remains unclear. The aim of this article is to investigate the involvement of CCR7 signaling in pathogenesis of primary pterygium.Methods: Slip lamp photographs of 85 pterygia patients were used to divide the pterygia into three groups, the width, extension, and area of pterygia were measured by computer software, the blood vessels of pterygium and general eye redness were quantitatively analyzed by a specific algorithm. Expression of CCR7 and its ligands C-C motif ligand 19 (CCL19) and C-C motif ligand 21 (CCL21) in normal conjunctivae and excised pterygia collected in surgery were analyzed by qRT-PCR and immunofluorescence staining. The phenotype of CCR7-expressing cells was identified by double-staining with major histocompatibility complex II (MHC II), CD11b and CD11c.Results: The level of CCR7 was significantly increased with 9.6-fold in pterygium when compared with normal conjunctivae (p=0.008). The higher expression of CCR7, the more blood vessels in pterygium ((R2=0.44, p<0.001) and more general ocular redness ((R2=0.25, p<0.001) pterygium patients had. CCR7 positive cells were co-located with D11b+, CD11c+ or MHC II in mature DCs. Immunofluorescence staining showed CCL21 co-staining with CCR7, which implied CCL21 may be a key ligand of CCR7 in pterygia, rather than CCL19. And CCR7 was significantly associated with the extension of pterygia (R2=0.083, p=0.047, β=0.192).Conclusions: Our research revealed a possible involvement of CCR7 in the migration of mature DCs and influence the progression of primary pterygia. Targeting CCR7 may be considered as a potential therapeutic approach for the treatment of pterygium.