Clinical relevance of endoscopic peri-appendiceal red patch in ulcerative colitis patients

Human intestinal B cells in inflammatory diseases

The intestinal lumen contains an abundance of bacteria, viruses and fungi alongside ingested material that shape the chronically active intestinal immune system from early life to maintain the integrity of the gut epithelial barrier. In health, the response is intricately balanced to provide active protection against pathogen invasion whilst tolerating food and avoiding inflammation. B cells are central to achieving this protection. Their activation and maturation generates the body's largest plasma cell population that secretes IgA, and the niches they provide support systemic immune cell specialization. For example, the gut supports the development and maturation of a splenic B cell subset - the marginal zone B cells. In addition, cells such as the T follicular helper cells, which are enriched in many autoinflammatory diseases, are intrinsically associated with the germinal centre microenvironment that is more abundant in the gut than in any other tissue in health. In this Review, we discuss intestinal B cells and their role when a loss of homeostasis results in intestinal and systemic inflammatory diseases.

Intestinal ultrasound detects an increased diameter and submucosal layer thickness in the appendix of patients with ulcerative colitis compared to healthy controls - a prospective cohort study

BACKGROUND

Increasing evidence suggests that appendicectomy as alternative treatment for ulcerative colitis (UC), especially in patients with histopathological appendiceal inflammation. Intestinal ultrasound (IUS) is a non-invasive diagnostic modality to characterise appendiceal inflammation.

AIMS

To assess appendiceal IUS characteristics in UC patients and compare findings to healthy controls (HC).

METHODS

In this prospective study, appendiceal IUS was performed in consecutive UC patients with active (A; n = 35) or quiescent (Q; n = 30) disease and in HC (n = 30). Transverse appendiceal diameter (TAD) and additional IUS parameters (bowel wall thickness, submucosal layer thickness and colour Doppler signal) were assessed.

RESULTS

The appendix was visualised in 41/65 UC patients (63.1%; A vs. Q: 23/35 vs. 18/30, p = 0.67) and 18/30 (60%) HC. UC patients had a higher TAD (A: 5.5 mm, Q: 5.0 mm, HC: 4.3 mm; A-HC p < 0.01; Q-HC p = 0.01, A-Q p = ns) and submucosal layer thickness (A: 1.0 mm, Q: 1.0 mm, HC: 0.7 mm; A-HC p < 0.01, Q-HC: p = 0.01, A-Q: p = ns) when compared to HC. A TAD ≥6 mm corresponding to an ultrasonographic suspicion of acute appendicitis was mainly reported in A-UC patients (A: 43%; Q: 6%; HC: 0%, p = 0.01) and occurred irrespective of disease extent. However, none of the patients had a clinical suspicion of acute appendicitis.

CONCLUSION

A TAD ≥6 mm was predominantly seen in A-UC. TAD was higher in UC patients compared to HC irrespective of disease activity and was characterised by an increased submucosal layer thickness. IUS therefore has the potential to identify UC patients with appendiceal inflammation.