S1965 B Adaptive: A Case of Rituximab-Associated Colitis and SARS-CoV-2 Vaccination

Abstract

Introduction: Rituximab (RTX) is a monoclonal antibody against the CD20 surface antigen on B-Cell lymphocytes and is used in various hematologic and autoimmune conditions. Our case describes a patient on RTX therapy with pancolitis that coincided with SARS-CoV-2 vaccination (Moderna-mRNA1273). We attempt to explore a potential correlation of mRNA vaccination platforms, RTX therapy and new onset colitis. Case description/methods: A 49 year old male presented with 6 weeks of watery, non-bloody diarrhea, right upper quadrant pain, >10 pound weight loss and fever. History was significant for stage IVa follicular lymphoma in remission on RTX maintenance therapy, splenectomy and SARS-CoV-2 vaccination (Moderna mRNA-1273) 2 days prior to onset of diarrhea. Infectious work up was negative and CT imaging demonstrated diffuse colonic wall thickening with new interval adjacent pancolonic fat stranding. Initial colonoscopy demonstrated diffuse scattered clean based ulcers between 1-8 mm in size throughout the colon and terminal ileum. Biopsies revealed active chronic ileitis with eosinophils, occasional crypt abscess and crypt destruction negative for HSV, CMV or signs of recurrent lymphoma. He was then treated with oral budesonide, bentyl and loperamide but returned 6 weeks later without any relief in abdominal pain or diarrhea. Repeat colonoscopy demonstrated circumferential hyperemia/edema with apthous ulcers throughout the colon. We plan to treat as a Crohn's patient with corticosteroid induction and trial Vedolizumab for maintenance of remission. Discussion: The novel use of mRNA vaccines has been noted to be game changing in its production time as well as its effectiveness at preventing COVID-19 illness. The mechanism of immunity is proposed to be a combination of generation of neutralizing antibodies and T-helper cell activation. To our knowledge, mRNA-1273 has not directly caused colitis. Literature also describes occurrences of fulminant colitis in patients on RTX therapy and is believed to be secondary to dysregulation caused by depletion of CD20+ B cells and upregulation of autoreactive T-cells. While RTX induced colitis may arise de novo, there may be a correlation between the immunogenicity of mRNA vaccines like mRNA-1273 and the induction of colitis in patients while on immunosuppressants. This case demonstrates the increased need for further evaluation of the pathogenesis of RTX induced colitis as well as the immunogenic response seen in COVID-19 vaccination platforms.