Unique display of a pathologic karyotype in Hodgkin's disease by Reed-Sternberg cells.

The clonality of Reed-Sternberg cells is still a matter of controversy. In Hodgkin's disease, these cells rarely constitute more than 2% of all cells in tissue biopsies of lymph node lesions, the rest being a large collection of various reactive cells. To determine in which cells the abnormal karyotype occurs, we studied two patients with Hodgkin's disease by a cytogenetic method allowing simultaneous analysis of cell morphology, immunologic phenotype, and karyotype in the same mitotic cell. The Ber-H2 (CD30) and Leu-M1 (CD15) monoclonal antibodies were used to identify mitotic Reed-Sternberg cells. In 24-48-hour cultures of lymph node cells from Hodgkin's lesions, there was a mixture of cells with an abnormal clonal karyotype and a normal karyotype. The abnormal clonal karyotype was restricted to Ber-H2- and Leu-M1-positive cells, i.e., the Reed-Sternberg cells. In keeping with these findings, most of the clonal atypical karyotypes occurred in kappa- and lambda-positive large cells, i.e., Reed-Sternberg cells. Mitotic cells with T markers (CD3,4,8) or B markers (CD22) had the normal karyotype. There were no mitoses in cells expressing the antigens recognized by Leu11 (CD16) or Leu11 + Leu7. These findings provide strong evidence suggesting that in Hodgkin's disease only the Reed-Sternberg cells possess a clonal karyotypic abnormality and thus are most probably the only neoplastic component in Hodgkin's disease.