Evidence for eosinophil degranulation in acute appendicitis

Finding of increased numbers of eosinophils in the muscle in cases of acute appendicitis has led to the hypothesis that it may have an allergic origin. This study aimed to measure the eosinophil degranulation resulting in a rise in the serum of eosinophil granule proteins that would be expected in such cases. The levels of serum eosinophil cationic protein (ECP) measured by chemiluminescence assay in acute appendicitis were compared, with those of appropriate controls. Mean (95% CI) serum ECP (microg/L) levels were: acute appendicitis 45.3 (27.7-63.0); normal appendix 22.7 (16.0-29.3); asthma 24.2 (4.6-43.8); and healthy volunteers 13.2 (8.3-18.1). In cases of acute appendicitis, there is an inverse relationship between duration of symptoms and serum ECP. However, this was not statistically significant. Significant local eosinophil activation and degranulation occurs in acute appendicitis, enough to cause a rise in serum levels of eosinophil chemotactic protein.