Assessment of clinicopathological characteristics and immunoexpression of COX-2 and IL-10 in oral pyogenic granuloma.

OBJECTIVE: The aim was to investigate the relationship between patient clinical background, histological features, and immunoexpression of COX-2 and IL-10 in oral pyogenic granuloma (PG).

DESIGN: Paraffin-embedded samples of oral PG (n=57) were prepared for histological and immunohistochemical assessment. Based on the histological features, the samples were categorised into lobular capillary hemangioma (LCH) and non-LCH subtypes. The epithelial lining, angiogenic index, inflammatory infiltrate density, and interstitial fibrosis, were assessed in haematoxylin-eosin stained sections. In addition, the marker expression estimation (stained cells/total cell number) was used to assess immunoreactivity for each sample.

RESULTS: Although there were no significant differences between histological subtypes regarding demographic and clinical parameters, mean values of microvessel count and inflammatory infiltrate density were significantly greater in the non-LCH PG subtype. Also, whilst cellular immunolocalisation patterns of COX-2 and IL-10 were similar, mean values of expression estimation of each immunomarker were significantly higher in non-LCH PGs in comparison with LCH subtypes. Furthermore, significant variations for immunohistochemical parameters were evident regarding to angiogenic index and inflammatory infiltrate density, but not concerning demographic and clinical data. Finally, linear regression analysis showed a significant positive correlation between the expression estimation of the two immunomarkers.

CONCLUSION: These findings suggest a role for COX-2 and IL-10 in the etiopathogenesis of oral PG and indicate that LCH and non-LCH histological subtypes represent different stages in the evolution of a single lesion with varying degrees of proliferative, angiogenic, and inflammatory activity.