Persistent Campylobacter jejuni enterocolitis after CAR T-cell therapy in a patient with hypogammaglobulinemic follicular lymphoma

ABSTRACT Background Campylobacter jejuni is a leading cause of bacterial gastroenteritis worldwide and typically results in self-limiting enterocolitis in immunocompetent individuals. In contrast, immunocompromised patients are at risk for severe, recurrent, or persistent infection. Chimeric antigen receptor (CAR) T-cell therapy targeting CD19 induces prolonged B-cell aplasia and hypogammaglobulinemia, predisposing patients to atypical infections. We report the first case of persistent and disseminated C. jejuni infection following CD19-directed CAR T-cell therapy, confirmed by whole-genome sequencing. Case Summary A 68-year-old man with relapsed follicular lymphoma underwent autologous CD19-directed CAR T-cell therapy and achieved complete remission. Pre-existing hypogammaglobulinemia worsened after treatment. Eighteen months later, he developed recurrent bacteremia and chronic enterocolitis caused by C. jejuni . Over the following year, he experienced severe watery diarrhea, 20 kg weight loss, and disseminated infection with a prosthetic hip abscess. More than 10 stool cultures remained positive despite multiple antibiotic regimens and two fecal microbiota transplantations. Whole-genome sequencing demonstrated a single clonal strain with minimal variation, confirming persistent infection rather than reinfection. Microbiological clearance was achieved after 8 weeks of oral gentamicin, followed by 2 weeks of intravenous meropenem and azithromycin, with sustained negative cultures and PCR. Conclusion Persistent and disseminated C. jejuni infection can occur in patients with hypogammaglobulinemia after CD19-directed CAR T-cell therapy. Whole-genome sequencing may help distinguish persistence from reinfection. Standard immunoglobulin replacement may be insufficient due to limited IgA and IgM, and prolonged combination antimicrobial therapy may be required for durable remission.