At the single-cell level, we found that those living with IBD (in remission) and PD had significantly more FTH1+ colonocytes interacting with other cell types, in particular IgA-producing plasma cells, relative to NHC colonocytes which primarily interacted with myofibroblasts (Fig. 4A; Fig. 4C–Ci). The gene discussed is CD79A; the disease is Parkinson disease.