Post-transplant colitis after kidney transplantation: clinical, endoscopic and histological features

Abstract

Chronic immunosuppression may increase the risk of post-transplant infection and medication-related injury and may also be responsible for the increased risk of gastrointestinal complications in kidney transplant recipients. Differentiating the various forms of post-transplant colitis is challenging, since most have similar clinical and histological features. This study evaluated the incidence of post-transplant gastrointestinal complications during screening colonoscopy. Kidney transplant recipients undergoing a colonoscopy for any reasons in the period 2014-2018 were included. Among the 134 patients completing the colonoscopy, 74 patients (56%) had an abnormal finding: an adenoma was found in 25 patients (18.6%), while 19 patients (14.1%) had colitis. Mycophenolic acid/related colitis was the most common colitis (6%), while 7 patients (5.2%) developed a de novo inflammatory bowel disease. Patients with post-transplant colitis were younger and with shorter time from transplant compared to patients without colitis. In conclusions, immunosuppression may predispose kidney transplant recipients to an increased risk of post-transplant colitis. Diagnostic colonoscopy should be encouraged in all transplant patients with refractory diarrhea and gastrointestinal symptoms to allow a prompt diagnosis and a timely treatment, finally improving the quality of life and long-term outcomes of affected patients.

Keywords: colitis; colonoscopy; cytomegalovirus; inflammatory bowel disease; kidney transplantation.

Figure 1

Mycophenolic Acid colitis. Endoscopic Findings. Colonoscopy demonstrated the presence of severe hyperemia to the right colon (A, B), with erosion of the colonic mucosa (C, D).

Figure 2

Mycophenolic acid colitis. Histological evaluation at 10x (A) and 20x (B). Colon biopsy retrieved from right colon during diagnostic colonoscopy shows (A) a severe eosinophils and plasma cells infiltrate of the submucosal layer (magnification 10x), (B) confirmed at higher magnification (20x).

Figure 3

Mycophenolate mofetil colitis. Histological examination. Biopsy of right colon: (A) severe eosinophils, lymphocytes and plasma cells infiltrate (10x), with (B) severe cryptitis (20x, white arrow) and cell apoptosis (black arrow).

Figure 4

Crohn-like colitis. Endoscopic findings. Multiple erosions and hyperemia of the mucosa of rectum (A) and sigma (B).

Figure 5

Crohn-like colitis. Histological features. (A) Irregular, severe eosinophils, neutrophils and plasma cells infiltrate in the submucosal layer (arrow). (B) Proliferation index Ki67 in the crypt, without apoptosis. Elevated Ki67 suggests regenerative activity as a consequence of crypt injury (cryptitis).

Figure 6

Cytomegalovirus colitis. Histological findings. Positivity for early cytomegalovirus antigen on immunochemistry.