TLR9 increased detection in positive infiltrating immune cells in active UC. Representative immunoperoxidase analysis of TLR9 expression of inflamed colonic tissue from six patients (panel A-D) uninflamed colonic tissue (panel E-F) and taken from a representative patient with UC. In the negative controls (neg. ctrl), the secondary antibody was omitted. Original magnification was 20 × (panels A, C, D).