To determine if reduced CD8 T cells in colonic tissue of IBD patients was indicative of imbalance in cell-mediated immunity versus humoral immunity towards the microbiota, we examined proportions of follicular helper [Tfh-like] cells, key inducers of antibody production through interaction with B cells in germinal centres, alongside the gut-homing function of T cells in PBMC [Figure 4a and Supplementary Figure S3, available as Supplementary data at ECCO-JCC online]. The gene discussed is CD8A; the disease is inflammatory bowel disease.