Immunohistochemistry using different fixation procedures. Immunohistochemical detection of pHp in human lung tissues using a mouse monoclonal primary antibody and horseradish-peroxidase conjugated polymer for detection with aminoethylcarbazole as a color-substrate. Image-acquisition was performed using a Leica DM-LB2-microscope with 40x PL-Fluotar optics and a Leica DFC 320 camera with Leica software (Leica Microsystems, Germany). White balance, and contrast were adjusted using FixFoto (Koopmann, Germany). A: FFPE lung tissue revealing granular staining in AECII (400x). B: HOPE-fixed lung tissue revealing ‘greasy’ staining (400x). C: HOPE-fixed lung section, which was briefly formalin-fixed after de-paraffinization displaying granular, FFPE-like staining (400x). A: one example of 115 FFPE lungs, B: one example of more than 15 HOPE-fixed lungs, C: one example of more than 15 lungs.