Histopathological diagnosis of infectious diseases using patients' sera.

It is expected that sera of patients suffering from infectious diseases contain high-titered IgG-type antibodies against the causative pathogen, particularly when inflammatory reactions, such as abscess or granuloma, are histopathologically confirmed in immunocompetent individuals. The present review article describes the usefulness of diluted patients' sera for identifying pathogens, by means of the indirect immunoperoxidase technique, in histopathologic specimens routinely embedded in paraffin. Infectious agents, such as bacteria, fungi, viruses, protozoa, and helminthes, were demonstrable with reliable sensitivity and limited specificity. Endogenous human immunoglobulins in paraffin sections were scarcely detected by the peroxidase-labeled secondary antibody. The method is simple, economic, useful, and beautiful for the histopathologic diagnosis of infectious diseases.