Abstract
Gastric, duodenal, and rectal biopsy specimens from 20 patients with chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma (NHL), not primarily of gastrointestinal origin, were examined using the immunogold-silver staining (IGSS) technique. In paraffin sections the presence of kappa and lambda surface immunoglobulin in lymphoid infiltrates was shown. Using this technique, nine patients were shown to have infiltration of the gastrointestinal mucosa by monoclonal B cells at one or more sites. In a further case a lymphoid aggregate was shown to express both kappa and lambda surface light chains, suggesting that it had a benign nature.