Background: The pathogenesis of appendicitis, the most common abdominal emergency for surgical intervention, is still unknown. Epidemiological differences between perforated and nonperforated appendicitis, polymorphism in the interleukin (IL)-6 gene associated with severity of appendicitis and a more pronounced Th1/Th17-like deviation in advanced compared to phlegmonous appendicitis has been reported. Altogether these findings may indicate that appendicitis harbours two different entities with different immuno-pathogenesis, one progressing to gangrene and perforation and one resolving. In this study we aimed to further investigate systemic cytokine profiles in a large sample of patients, with advanced and phlegmonous appendicitis from a Th1, Th2, Th17 and innate perspective, and also clarify if time as duration of symptoms could explain the differences.
Methods: Blood samples were preoperatively collected from patients with advanced (n=61) and phlegmonous appendicitis (n=108). The Th1-associated (IFN-γ, IL-12p70), Th2-associated (IL-4, IL-5), Th17-associated (IL-17, IL-6, CCL20, CCL2) and innate-associated (IL-1β, IL-6, MPO, CXCL8, GM-CSF), markers were analyzed in plasma using multiplex bead assay.
Results: Patients with advanced appendicitis had increased levels of IL-6 (P=0.0001), CCL2 (P=0.001), MPO (P=0.039), IL-12p70 (P=0.010) and CCL20 (P=0.002) as compared to phlegmonous appendicitis and age, sex or duration of symptoms at sampling could not explain the differences.
Conclusion: The findings suggest a dysregulated Th1/Th17 type inflammation in advanced appendicitis, already early in the disease course, that eventuates in gangrene and perforation and gives further support to the notion of appendicitis as two entities.