Rearranging antigen-receptor genes in enriched Reed-Sternberg cell fractions of Hodgkin's disease.

Abstract

Molecular genetic analysis of rearranging antigen-receptor genes in non-Hodgkin's lymphomas has revealed the clonality and lineage in the majority of cases. In an analogous approach, we sought to apply gene rearrangement analysis to Hodgkin's disease to understand better the clonality and origin of this disorder. However, the putative neoplastic cell of Hodgkin's disease, the Reed-Sternberg cell and its variants, is extraordinarily rare in most cases of Hodgkin's disease. On the average, Reed-Sternberg cells and variants represent 0.1 per cent of total cell suspensions of nodular sclerosing Hodgkin's disease. As this frequency is below the minimum threshold of sensitivity of the Southern blot assay, we attempted to enrich for Reed-Sternberg cells before DNA extraction and analysis. Using either elutrition or Percoll density gradient centrifugation, we were able to enrich the percentage of Reed-Sternberg cells and variants to above 1 per cent in five cases of nodular sclerosing Hodgkin's disease. In three of these cases, immunoglobulin gene rearrangements were identified, but no T cell receptor gene rearrangements were seen. No rearrangements were detected in unseparated cells or in the Reed-Sternberg cell-depleted fractions. In addition, the L428 Hodgkin's disease cell line was found to have one rearranged and one deleted heavy-chain gene, a rearranged kappa gene, a rearranged lambda gene, and a single rearranged beta allele. No rearrangements of the T gamma gene were found in L428. Taken together, these findings indicate that clonal cell populations are present in Hodgkin's disease and suggest the possibility of a clonally expanded lymphoid cell in this disorder.