Histological healing after infliximab induction therapy in children with ulcerative colitis

Aim: To verify the impact of induction therapy with infliximab (IFX) on mucosal healing in children with ulcerative colitis (UC).

Methods: The study included all UC pediatric patients treated with IFX at our center over the last 10 years. The data were collected from patients' medical charts and analyzed retrospectively. A total of 16 patients with UC underwent colonoscopy with sample collection before and after three IFX injections. Pediatric Ulcerative Colitis Activity Index (PUCAI) was used to assess the clinical condition; endoscopic features were classified according to the Baron scale; and histological changes were evaluated according to the protocol of The British Society of Gastroenterology and Geboes Index. Clinical response was defined as a ≥ 20-point reduction in PUCAI index, and clinical remission as PUCAI index < 10 points. Endoscopic mucosal remission was defined as completely normal (score 0) on the Baron scale. Histological remission was defined as grade 0 in the Geboes Index. To assess correlation between variables, Spearman's rank correlation coefficient was used.

Results: Clinical remission (PUCAI < 10) at week 8 was achieved in 68.75% of investigated subjects. Endoscopic mucosal remission at week 8 (Baron 0) was observed in 12.5% of patients. Histological remission (Geboes 0) after induction therapy with IFX was noticed in 18.75% cases. A general histological improvement, expressed by normal surface and crypt architecture, number of crypts, and lamina propria cellularity, was observed in six (37.5%) patients; there was no improvement in nine (56.25%) individuals, and worsening was observed in one (3.75%) case. Changes were not related to UC location. A reduction of inflammatory process was observed in 10 (62.5%) patients; there were no changes in four (25%) individuals, and the inflammation became more severe in two (12.5 %) cases. Simultaneous clinical, endoscopic and histological improvement of parameters assessing disease activity at week 8 was noticed in six (37.5%) patients. 55.5% of investigated patients with normal mucosa seen on endoscopy showed no inflammation on histology. A Baron score of 2 and 3 showed a good correlation with histology results (78.2% of patients with a Geboes Index ≥ 3).

Conclusion: IFX has a positive histological effect in more than one-third of UC patients. IFX reduces intestinal inflammation and improves clinical condition.