Decreased lymphatic vessel density is associated with postoperative endoscopic recurrence in Crohn's disease

Increased lymphatic vessel (LV) density has been found in uninflamed intestinal wall of patients with Crohn's disease (CD). The goal of the study was to search for an association between LV density in the proximal ileal resection margin at the time of surgery and endoscopic recurrence.

Ileocolonic resection specimens were obtained from 28 CD patients and 10 control subjects. The ileal proximal uninflamed section was used for the histological quantification of LV using immunohistochemistry with D2-40 antibody in the mucosa and submucosa. Quantification of LV was performed in 8 consecutive fields and was blinded to recurrence score. Patients were divided into 2 groups based on the presence (Rutgeerts score, i3/i4) (R+) or absence (Rutgeerts score, i0/i1) (R-) of endoscopic recurrence 1 year after the surgery. All patients were free of immunomodulators or biologics between surgery and postoperative endoscopy.

Median LV density was lower in control subjects than in CD patients in the mucosa (4.5%; interquartile range [IQR], 3.6-5.3 versus 5.9%; IQR, 4.2-8.5; P = 0.04) and submucosa (2.4%; IQR, 1.9-3.6 versus 5.7%; IQR, 4.3-6.9; P < 0.01). R- patients had a higher LV density in the proximal resection margin at surgery than R+ patients, both in the mucosa (8.5%; IQR, 6.5-10.3 versus 4.4%; IQR, 3.1-6.1; P < 0.01) and in the submucosa (6.3%; IQR, 5.5-9.3 versus 5.3%; IQR, 3.4-5.9; P = 0.03). Mucosal LV density greater than 7% predicted the absence of endoscopic recurrence at 1 year, with a sensitivity of 81% and a specificity of 75%.

Decreased LV density is associated with high risk of endoscopic recurrence after surgery. Therapies that improve lymphatic flow in the gut may reduce the incidence of endoscopic recurrence.