The aim of this study was to evaluate serum levels of Infliximab (IFX) in patients with Crohn’s disease (CD) who underwent an ileocolonic resection and to correlate them with the presence or absence of endoscopic disease recurrence.

An observational and cross-sectional study was carried out in patients from 2 treatment centers in Curitiba-PR, with CD, who underwent ileocaecal resection and used IFX after surgery. Drug serum levels were measured, and colonoscopy was performed 30 days before or after collection. Patients were then divided into two groups: with or without endoscopic recurrence (defined as a Rutgeerts score greater than or equal to 2), and mean serum IFX levels were identified and compared. The primary objective was the correlation between recurrence and the median levels of IFX, performed comparatively between groups.

Of the 21 patients included in the study, 14 had no endoscopic recurrence and 7 had it. There was no difference between groups in terms of baseline patient characteristics, mono or combo therapy treatment, serum albumin, and the time elapsed between collection of serum levels and diagnosis, surgery, and beginning of therapy. Patients with endoscopic recurrence used more biologics previously (P = 0.027). There was no difference between the median values of serum IFX levels between the groups: (4.71 [0.03–14.4]) in patients without recurrence versus (2.18 [0.88–14]) in those with recurrence (P = 0.601).

Low serum IFX levels were not correlated with postoperative endoscopic recurrence. Studies with a larger number of patients are needed to better test the proposed hypothesis.