Characteristic expression and significance of CCL19 in different tissue types in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous disease, with varying immunological and histopathological features. The CC chemokine ligand 19 (CCL19) can stimulate T cells and antigen-presenting cells into secondary lymphoid node formation, as observed in allergic rhinitis, inflammatory bowel disease and other inflammatory disorders. The purpose of this study was to investigate the expression and significance of CCL19 in CRS. Samples of uncinate process mucosa or nasal polyps were taken from patients with CRS (without or with nasal polyps) and normal controls during surgery. Hematoxylin and eosin, periodic acid Schiff and Masson trichrome staining were used for analysis of the nasal polyps. Western blot and immunofluorescence were used to detect CCL19 expression in the nasal polyps and normal nasal mucosa tissues. Spearman correlation analysis was used to analyze the association between CCL19 and blood eosinophil counts. The results showed that CCL19 protein levels in CRS (with or without nasal polyps) were significantly upregulated compared with those in controls. CCL19 expression in eosinophilic CRS was significantly higher than in non-eosinophilic CRS. CCL19 expression in fibroinflammatory and edematous type CRS with nasal polyps was higher than in controls; the upregulation was greater in the edematous type. Immunofluorescence assays showed that CCL19 was mainly expressed by CD68⁺ macrophages. Spearman correlation analysis demonstrated a positive correlation between CCL19 and blood eosinophils. The upregulation of CCL19 in CRS may play a protective role by limiting eosinophil infiltration and the extent of edema to exert anti-inflammatory and immunomodulatory effects.