CD4 and inflammatory bowel disease: After three vaccine doses we found no impact of an IBD diagnosis on T cell responses compared to healthy controls by multivariable linear regression, and CD4 and CD8 T cell responses reached similar levels in both patients with IBD and healthy controls (CD4 T cells, 0.11% (0.052–0.20) vs. 0.13% (0.080–0.20); CD8 T cells, 0.031% (0.008–0.11) vs. 0.022% (0.012–0.14), Fig. 3b and c).