PDCD1 and inflammatory bowel disease: Using multiplexed IHC, cell density (cells/mm2) of helper T cell (Th), cytotoxic T cell (Tc), regulatory T cell (Treg), PD-1 + cells, PD-1 + Th, PD-1 + Tc, and PD-1 + Treg were compared between the IBD and OID groups.