There are few data on how histological signs of inflammation develop under treatment with infliximab (IFX). We investigated the patterns of histological features of inflammation in patients with UC in sustained clinical and endoscopic remission under IFX.

We performed a retrospective study on 47 patients with UC in clinical and endoscopic remission and undergoing surveillance colonoscopy with biopsies while receiving maintenance therapy with IFX. Each colonic segment was evaluated based on the Mayo endoscopic subscore and the Geboes histology score (range 0−5.4).

Globally, 6110 biopsy specimens were collected from 235 colonoscopies. At the beginning of the follow-up, histological features of inflammation were found in 48.9% of patients receiving maintenance IFX therapy; 25.9% of them had at least moderate inflammation based on histology scores. At the end of the follow-up, when patients were still under endoscopic and clinical remission, 40.4% of patients had at least one biopsy specimen with evidence of any histological inflammation during the follow-up, and 19.1% had biopsy specimens that met the Geboes criteria for histological inflammation and architectural alteration. In none of the different disease locations (pancolitis, left-sided colitis, distal colitis) histological inflammation improved significantly during the follow-up.

Patients in clinical and endoscopic remission from UC under IFX still frequently have histological features of inflammation.