L and H cells of nodular lymphocyte predominant Hodgkin's disease show immunoglobulin light-chain restriction.

The nodular form of lymphocyte predominant Hodgkin's disease (NLPHD) is widely accepted to be a B-cell-derived neoplasm. Despite this consensus, previous studies have not shown monotypic immunoglobulin (Ig) light-chain expression by the putatively malignant L & H cells. We have studied paraffin-embedded tissue from 19 cases of NLPHD for the presence of Ig light and heavy chains and J chain. In addition, frozen tissue, available from one case, was examined with antibodies to light chains. In paraffin material, in each case L & H cells in individual nodules were examined for the presence of Ig light chain restriction. Kappa-light-chain restriction was detected in all L & H cells in all nodules in 5/19 cases (26.5%) and this was confirmed in frozen sections available from one case. Of the remaining 14 cases, 13 (68.5%) showed kappa-light-chain restriction in a proportion of nodules and in 1 case light-chain restriction was not observed. Of 14 cases stained with antibodies to Ig heavy chains 13 contained IgG, and in 1 case no heavy chains were demonstrable. Most L & H cells in 15 cases examined contained J chain. Our finding of monotypic L & H cells in NLPHD in 95% of our investigated cases provides strong evidence for the neoplastic nature of L & H cells and supports the hypothesis that NLPHD is a malignant nonHodgkin's B-cell lymphoma.