The demonstration of plasma cells and other immunoglobulin-containing cells in formalin-fixed, paraffin-embedded tissues using peroxidase-labelled antibody.

A method is described for the demonstration of specific immunoglobulin in plasma cells and other lymphoid cells in sections taken from routine surgical histology specimens which have been formalin fixed and paraffin embedded. An indirect sandwich technique was employed using specific rabbit antihuman immunoglobulin antisera (anti-K, L, G, A, and M) and a swine antirabbit serum Ig G, conjugated with horseradish peroxidase. The presence of plasma cells was revealed by staining the tissue-bound peroxidase-labelled antibody, having previously stained the endogenous peroxidase a contrasting colour. It was possible to demonstrate clearly immunoglobulin in the plasma cells of tissues processed and embedded several years previously. Some of the potential uses of the method are discussed.