The cytochemical demonstration of intracellular immunoglobulin. In neoplasms of lymphoreticular tissue.

An immunoglobulin-enzyme bridge technique has been employed for the selective localization of immunoglobulin-producing cells in spleen, lymph nodes, and lymphoreticular tumors fixed highly for optimal immunocytochemistry or processed routinely for surgical diagnosis. Immunostaining for immunoglobulin was encountered consistently in the specially fixed tissues and was observed in some of the surgical specimens in areas where presumably fixation was satisfactory. Many, but not all, of the tumor cells in histocytic lymphoma (reticulum cell sarcoma) of spleen and of brain stained for IgG, but none evidenced reactivity for IgM or IgA. In Hodgkin's tumors, the prevalence of IgG-reactive stromal immunocytes in or between tumor areas was greatest in the nodular sclerosing form of the disease, abundant in mixed cellular, and least in lymphocyte-predominant and lymphocyte-depleted types. Immunocytes showing reactivity for IgG greatly exceeded those staining for IgM or IgA. Hodgkin's tumor cells immunostained frequently for IgG, infrequently for IgM, not at all for IgA, and in one instance, stained for k but not for lambda light chains. Individual tumor cells failed to stain for more than one type of Ig or light chain. The proportion of Ig reactive vs. unstained tumor cells correlated with the prevalence of immunocytes in the different Hodgkin's categories. Reed-Sternberg cells differed in their fine structure in ways which possibly correspond with the presence or absence of Ig shown at the light microscope level. Tumor cells in Hodgkin's disease and reticulum cell sarcoma also disclosed argyrophilia and strong staining indicative of ribonucleic acid with a Schiff-methylene blue procedure.