The Circulating Fibrocyte - a Novel and Accurate Biomarker in Diagnosing Acute Appendicitis in Adults

Acute appendicitis (AA) is the commonest abdominal emergency. Despite its high prevalence, the diagnosis of appendicitis remains a challenge. The clinical presentation is frequently atypical and symptoms often overlap with many other conditions. Coupled with this, failure to reach a prompt diagnosis can result in adverse outcomes.

Circulating fibrocytes (CFs) were first described in 1994 by Richard Bucala. They are haematopoietic cells derived from the bone marrow. They circulate in the monocyte fraction and can differentiate into myelofibrocytes, fibroblasts and adipocytes (among other cell types). They have a prominent role in inflammatory and healing processes, and in the development of fibrosis.

No studies to date have examined the role of CFs in acute appendicitis. Thus, the aims of this clinical trial were (1) to determine if CFs are altered in acute appendicitis, (2) to assess and compare their diagnostic accuracy with CRP, WCC, neutrophils, lymphocytes, neutrophils-lymphocytes ratio (NLR), monocytes, basophils and eosinophils, and (3) to determine the most reliable predictors in diagnosing AA.

A prospective cohort study was undertaken to (1) determine circulating fibrocytes levels (CF) in patients with histologically confirmed acute appendicitis (AA), and (2) to determine the sensitivity and specificity of circulating CF levels in the diagnosis of AA, in adults (age ≥ 16 years) presenting acutely with right iliac fossa pain, at the University hospital Limerick. The diagnosis of appendicitis was confirmed by histopathological assessment following appendicectomy.

Patients were divided in three cohorts following their final diagnosis on discharge and based on the histopathology results. (1) patients with RIFP who underwent an appendicectomy and had a normal appendix at histological assessment i.e histologically proven normal appendix group (HPNG). (2) patients with RIFP who underwent an appendicectomy and had an inflamed appendix at histological assessment i.e histologically proven appendicitis group (HPAG). (3) patients with RIFP who had an alternate diagnosis on discharge other than appendicitis i.e alternative diagnosis group (ADG). Another cohort was added as (4) healthy controls.