LIGHT-CHAIN MESSENGER-RNA IN LYMPHOCYTE-PREDOMINANT AND MIXED-CELLULARITY HODGKINS-DISEASE

There is growing evidence for a B-cell lineage of lymphocyte-predomina nt Hodgkin's disease (1). To support this assumption, in situ hybridiz ation techniques were used to detect immunoglobulin light-chain mRNA i n 44 formalin-fixed specimens of Hodgkin's lymphoma (22 of lymphocyte- predominant Hodgkin's disease; 22 of mixed-cellularity Hodgkin's disea se). In addition, immunoglobulin light chains were evaluated by polycl onal antisera All specimens had been unequivocally diagnosed histologi cally by the referees of the German Hodgkin Trial and been immunopheno typed by monoclonal antibodies against CD15, CD20, CD30, and CD45, Lig ht-chain mRNA coding either for kappa or for lambda could be detected by an enhanced irt situ hybridization protocol using microwave heating in tbe lymphocytic and histiocytic cells of 14 (64%) of 22 specimens of lymphocyte-predominant Hodgkin's disease tested. None of the specim ens, however, belonging to one of the classic subtypes of Hodgkin's di sease (mixed-cellularity Hodgkin's disease) showed positivity for mRNA in the giant tumor cells. Om results support the idea that lymphocyte -predominant Hodgkin's disease represents a B-cell malignancy that is a entity separate from classic Hodgkin's disease. Diverging results of former studies in assessing light-chain mRNA in lymphocytic and histi ocytic cells probably reflect problems with the detection threshold, i .e., the sensitivity of the techniques applied.