P883 Impaired long-term quantitative cellular response to SARS-COV-2 vaccine in thiopurine-treated IBD patients

Abstract

Abstract Background SARS-CoV-2 mRNA vaccine induces a robust immune response in most patients with inflammatory bowel disease (IBD). However, humoral short-term response appears to be reduced in patients receiving anti-TNF agents or tofacitinib, even after booster doses. Data on long-term immune response is limited. We aimed to assess short and long-term humoral and T-cell response to SARS-CoV-2 mRNA vaccine in IBD patients receiving anti-TNF and/or thiopurines. Methods A prospective, longitudinal study was carried out in IBD patients receiving thiopurines, anti-TNF mono, or combo therapy. Patients had received between 2 and 4 doses of mRNA SARS-CoV-2 vaccine. Cellular and humoral response to the vaccine was assessed by serum interferon-gamma release assay (IGRA) and antibody SARS-CoV-2, respectively. We defined short-term response as humoral and T-cell response six weeks after the second vaccine and long-term response 6 to 12 months after that. Primary outcome was to determine if T-cell immune response differs in IBD patients receiving anti-TNF versus thiopurines. Results We recruited 148 IBD patients, 57 treated with anti-TNF monotherapy, 53 with anti-TNF combo, and 38 with thiopurines. Short-term T-cell and humoral responses were similar between the three groups. However, long-term T-cell concentration was reduced in thiopurine-treated (median 0.7 UI/mL [0.26-2.35]; p<0.05) and anti-TNF-combo-treated patients (median 0.4 UI/mL [0.22-1.13]; p<0.01) when compared to anti-TNF monotherapy (median 2.2 UI/mL [1-4.15]). Multivariate analysis showed that anti-TNF monotherapy (-0.93, p<0.05) and decreased time between vaccination and T-cell response measurement (0.04 [.00005-.078] p=0.05) were associated with increased T-cell concentration long-term when compared to the other groups of patients. Conclusion We found a diminished long-term quantitative cellular response in our cohort of IBD patients vaccinated for SARS-CoV-2 treated with thiopurines or combo therapy compared with anti-TNF monotherapy. These findings highlight the recommendation to receive booster doses in IBD patients, specially those receiving thiopurines.