"Proof of the association between adenovirus infection and appendicitis in children through pathological evidence"

Abstract

Background : Appendicitis is inflammation and swelling of the appendix that can occur at any age. It can be caused by fecalith blocking the appendix entrance and has been associated with lamina propria thickening due to infection. Some reports have observed a relation between appendicitis and hyperplastic lymphoid tissue, which might be caused by infections like adenovirus, while others have linked adenovirus infection and appendicitis in children. Methods : We performed a retrospective pathology review of tissue samples from 120 children aged <18 years who underwent an appendectomy in patients with appendicitis at Cathay General Hospital between January 2016 and January 2021. Pathological tissues from appendectomies were processed into formalin-fixed paraffin embedding (FFPE). Adenovirus immunohistochemistry (IHC) and quantitative polymerase chain reaction (qPCR) were analyzed to determine the positive rate of adenovirus in appendicitis. Results : Extracted DNA quality was assessed at an optical density (OD) ratio of 260 nm and OD 280 nm (≥1.8). Concentrations ranged from 91–1087 ng/µL. None of control subjects were positive for IHC with anti-adenovirus antibody and qPCR analysis (Cq ≤40). However, the positive rates were significantly higher in patients by IHC detection (25.8%, 31 of 120; P = 0.010) and qPCR analysis (35.0%, 42 of 120; P = 0.002) Conclusion : Our study directly confirmed the relationship between adenovirus infection and appendicitis using retrospective pathology evidence. IHC analysis and qPCR detection confirmed evidence of adenovirus infection in patients with appendicitis. Further, qPCR is as useful and reliable as IHC for diagnosing adenovirus in appendicitis, showing higher sensitivity compared with IHC.