Immunocytochemical analysis of cellular infiltrates in human appendicitis

This study was conducted to determine the immunologic cellular composition in human appendicitis and its association with the development of perforated appendicitis. Appendiceal specimens from 27 patients with acute appendicitis were immunostained to detect lymphocyte surface markers. Moreover, the lymphocyte surface markers of peripheral blood were analyzed by laser flow cytometry in 12 patients. Helper T lymphocytes (CD4) were present in all the patients, while B lymphocytes (CD19), natural killer (NK) cells (CD56), and cytotoxic T lymphocytes (CD8) were present in 7 (70%), 10 (100%), and 9 patients (90%) with perforated appendicitis, and in 12 (63.2%), 10 (58.8%), and 6 (54.5%) patients without perforation, respectively. There were significant differences between the patients with a perforated appendix and those without perforation, in the positivity rate for CD8 and CD56 cells (P < 0.05). The number of cells positive for CD56, being NK cells, in the blood from the patients with perforation was significantly lower than that in the blood from those without perforation (P < 0.05). The infiltration of a greater number of cytotoxic T lymphocytes and NK cells was observed in the appendices from patients with perforated appendicitis than in those from patients with nonperforated appendicitis.