Mast cells in surgically resected appendices.

Mast cells are known to be effector cells in various inflammatory reactions, but their role in appendicitis is unclear. The present study was undertaken to investigate the extent of mast cell involvement in appendicitis and evaluate their possible role. A total of 150 appendices including normal and inflamed appendices, were assessed for their histological changes and density of neutrophil, lymphocyte and eosinophil infiltration. The mast cells were counted in 1% toluidine blue-stained sections. It was found that eosinophil counts in all the layers were significantly low in normal appendices (P<0.01) and in chronic appendicitis (P<0.1) as compared to acute appendicitis. Mast cell counts were lowest in normal appendices, significantly higher in acute appendicitis (P<0.01) and highest in chronic appendicitis (P<0.001). Obstruction due to faecoliths or parasites were seen in only 20.1% and 2.1% of the inflamed appendices respectively. Hence a Type I hypersensitivity reaction with release of mediators by mast cells might be another triggering factor for the sequence of events leading to appendicitis.