Detection of immunoglobulin light chain mRNA in nodular sclerosing Hodgkin''s disease by in situ hybridization with biotinylated oligonucleotide probes compared with immunohistochemical staining with poly- and monoclonal antibodies

In order to elucidate the origin of the Hodgkin's and Reed-Sternberg cells, the expression of immunoglobulin kappa- and lambda light chain mRNA in 23 cases of nodular sclerosing and two cases of mixed cellularity Hodgkin's disease was examined by in situ hybridization using biotinylated oligonucleotide probes and compared with immunohistochemical staining with mono- and polyclonal antibodies against immunoglobulin kappa- and lambda light chains. No hybridization signals were seen in Hodgkin's or Reed-Sternberg cells in any of the cases. Polyclonal staining with polyclonal anti-immunoglobulin light chain antibodies was seen in Hodgkin's and Reed-Sternberg cells in 12 cases of nodular sclerosis and in two cases of mixed cellularity and with monoclonal antibodies in three cases of nodular sclerosis, but in no cases of mixed cellularity. In all cases, there was polyclonal labelling of plasma cells with both the oligonucleotide probes and the antibodies. In five cases, the Hodgkin's and Reed-Sternberg cells were also stained with one of the B-cell antibodies L26, MB2 or LN1. Lack of mRNA signals in Hodgkin's and Reed-Sternberg cells might indicate that these cells in Hodgkin's disease of the nodular sclerosis subtype are either not B-cell derived or they are early B-cells (precursor B-cells) not yet able to produce immunoglobulin light chain mRNA, at least not at a level detectable by in situ hybridization. Immunohistochemical staining of Hodgkin's and Reed-Sternberg cells, however, with antibodies against immunoglobulin kappa and lambda light chains may be explained by cellular uptake of the light chains, but the difference in reactivity between poly- and monoclonal antibodies cannot be explained at present.