IMMUNOCYTOCHEMICAL IDENTIFICATION OF MALL ORY BODIES - THEORETICAL-ANALYSIS ABOUT THEIR FORMATION

Background: Mallory bodies are hepatocyte intracytoplasmic inclusions frequently observed in liver diseases. They contain altered intermedia ry filaments that have immunoreactivity with epidermic antikeratin ant ibodies (A-QEp). They also contain ubiquitin (Ubq) a 76 residue polype ptide that has an important role in the proteolysis of rapid exchange and abnormal cytosol proteins. Aim: To standardize an immunohistochemi cal method for the detection of Mallory bodies in percutaneous liver b iopsies. Methods: A-QEp and A-Ubq polyclonal antibodies were used in t he study of 131 percutaneous liver biopsies obtained from patients wit h different liver diseases. Mallory body immunoreactivity was confirme d with immunoelectron microscopy. Results: Mallory bodies had scanty i mmunostaining with A-QEp, specially in formalin fixed biopsies. There was a specific and sensitive staining with A-Ubq, that was not influen ced by the fixation method. Immunoelectron microscopy demonstrated tha t Mallory bodies ae partially formed by altered intermediate filaments . Conclusions: Antibodies against ubiquitin may be very useful for the detection of Mallory bodies in liver biopsies.