RESUMO
Immunohistochemistry allows pathologists to examine the presence of specific cell products in tissue sections. It provides a bridge between the morphological and functional aspects of a lesion since it allows for the examination of the presence and/or abscence of a product "in situ". The use of monoclonal antibodies offer advantages over policlonal antisera. Bacground staining is usually low vecause of the high specificity of monoclonal antibodies and the absence of "unwanted antibodies" present in policlcocnal antisera. Standardization of protocols is possible due to the reliable affinity and titre of monoclonal antisera. However there are some disadvantages with the use of monoclonal antibodies. Paradoxically they are related to the hight specificity of these antibodies. The single antigenic determinant recognized by a monoclonal antibody can and is often denatured or destroy by fixation. Also this single antigenic determinant may be present in different substances and are capable of an specifric but undesirable staining. There are some technical tricks to aboid both problems. In the future most substance will be reconized by monoclonal antibodies and so the histophatologic diagnosis will achieved an objective nature