A new method for demonstrating antigens in paraffin sections of formol sublimate-fixed tissue is described that utilizes an "indirect" immunohistological technique employing immunoglobulin adsorbed to colloidal gold as the secondary antiserum. The gold particles introduced to antigenic sites are revealed by a silver precipitation reaction. This technique, the immunogold-silver staining method, is of much enhanced sensitivity (up to 200-fold) as corn-''...

Fixatives, fixation additives, paraffin processing reagents, and immunochemical reagents were investigated for effects on preservation of T-lymphocyte surface membrane antigens CD3, CD4, and CD8 in human tonsil. Individual reagent effects were assessed in frozen sections by use of monoclonal antibodies and this information was used to optimize T-cell immunostaining in paraffin sections. Harmful factors were fixation delay, fixation at acid pH, fixation and processing at temperatures above 4 degrees C, hot paraffin wax, proteolytic enzymes, methanolic hydrogen peroxide, Triton X-100, and prolonged iodine treatment. Optimal T-cell demonstration in paraffin sections followed tissue fixation in periodate-lysine-paraformaldehyde dichromate at 4 degrees C, pH 7.5; processing through isopropanol, then xylene or chloroform, at 4 degrees C; and embedding in low melting point wax at 45-50 degrees C. Graded antigen stability occurred: CD3 most stable, CD8 least, and CD4 intermediate. CD4 and CD8 antigen preservation in paraffin sections required critical optimal tissue handling. CD3 was more stable and was also demonstrated in tissue fixed in commercial formalin, glutaraldehyde, and Bouin's fluid when fixation and processing conditions were optimized for pH and temperature. Of the fixation additives studied, polyethylene glycol and several potassium and magnesium salts enhanced immunostaining, whereas calcium chloride and lidocaine were deleterious.

B cell non-Hodgkin lymphoma of the follicular subtype (grade 3/3) affecting the nasopharynx and breast, and containing foci of Langerhans cell histiocytosis, was diagnosed in a 56 year old white woman who was a longstanding heavy smoker. Four years before this she had developed stage 1a mixed cellularity Hodgkin lymphoma affecting the right inguinal region, which was treated by irradiation and chemotherapy without recurrence. Review of the original Hodgkin lymphoma histology demonstrated a small focus of Langerhans cell histiocytosis. This is thought to be the first recorded case of Langerhans cell histiocytosis occurring in a sequential discordant lymphoma. Its importance is discussed.

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The identification of lymphoid surface membrane antigens in tissue sections using immunohistochemical techniques is becoming increasingly important for the diagnosis and classification of lymphoproliferative disorders. Many of the lymphocyte specific monoclonal antibodies used, however, can only be applied to frozen tissue sections. In this paper we report the successful application of a number of these antibodies to paraffin processed tissue utilizing alternative fixatives and the highly sensitive immunogold-silver staining method. The best fixatives for this purpose were formol dichromate, periodate-lysine-paraformaldehyde (PLP) and a novel fixative formed from the addition of a dichromate solution to PLP.