De novo Inflammatory Bowel Disease following Liver and Heart Transplantation: A Case Series Exploring the Role of IL-23 Pathway-Targeted Therapy.

INTRODUCTION

De novo inflammatory bowel disease (IBD) is a rare but clinically significant complication after solid organ transplantation (SOT), with incidence higher than that in the general population. Its pathogenesis, diagnostic challenges, and optimal management remain poorly defined. We describe 6 cases of de novo IBD following liver or heart transplantation and evaluate therapeutic outcomes with selective biologics targeting the IL-23 pathway.

METHODS

Six SOT recipients (3 liver, 3 heart) developed new-onset ulcerative colitis-type (UC-type, n = 3) or Crohn's disease-like (CD-like, n = 3) IBD after a median of 47.5 months post-transplantation. None had pre-transplant intestinal symptoms; colonoscopy was negative before transplantation in 2 UC-type cases. Alternative etiologies - including cytomegalovirus colitis, drug-induced colitis, and post-transplant lymphoproliferative disorder - were rigorously excluded. Treatments included systemic corticosteroids, mirikizumab, ustekinumab, or risankizumab. Median follow-up was 15.6 months.

RESULTS

Corticosteroids induced remission in 2 UC-type cases, while one steroid-refractory UC-type case and all CD-like cases achieved clinical improvement and endoscopic response or remission with IL-23-targeted biologics. No opportunistic infections, severe biologic-related adverse events, or graft rejection were observed.

CONCLUSIONS

De novo IBD emerged years after SOT, with variable phenotypes despite baseline immunosuppression. IL-23 pathway inhibitors demonstrated favorable efficacy and safety in this vulnerable population, representing a promising strategy warranting further prospective evaluation.