Ultrastructural immunolabeling in renal diseases. Past, present and future expectations.

The use of immunoelectron microscopy in the evaluation of renal diseases represents a valuable addition to existing techniques. The ability to immunolabel immune-complex deposits for light- and heavy-chain determinants, and complement fractions virtually eliminates the need for traditional immunofluorescence. One of the main advantages of performing immunoelectron microscopy relates to the fact that immunologic events can be adequately correlated morphologically with the degree and type of tissue reactions in the various renal compartments. Immunopathogenetic mechanisms can be clearly evaluated with this technique. The need to submit specimens in different fixatives is eliminated and all diagnostic modalities can be performed on a single fragment of tissue. The examination of the thick sections prepared from plastic-embedded tissue for survey provides excellent material for interpretation of findings at the light-microscopic level. These sections can be stained with hematoxylin/eosin, trichrome, silver methenamine and PAS stains with excellent results. The time and resources needed for processing renal biopsies can be significantly reduced by utilizing the proposed methodology. Likewise, interpretation of results may benefit from utilization of the same fragment for all diagnostic modalities.