This report describes the geno- and immunophenotypic analysis of the Hodgkin's disease-derived cell lines HDLM-2, KM-H2, and L-428. The lines were all positive for the antigens CD15 (Leu-M1), CD30 (Ki-1), Hefi-1 (antigen detected by a monoclonal antibody produced against L-428), HLA class I and II, and activation/proliferation markers. The cells from all 3 cell lines lacked almost all cell lineage-associated/specific markers: HDLM-2 was only CD2+, KM-H2 was only CD9+ and CD21+, and L-428 was negative for all the specific markers tested. Genomic analysis of HDLM-2 cells revealed monoclonal rearrangements of T cell receptor beta and gamma loci and germ line configuration of immunoglobulin genes. Immunoglobulin heavy chain genes were rearranged in KM-H2 and L-428. These data suggest a possible lymphoid origin for HDLM-2, KM-H2, and L-428. Although the data presented do not provide formal proof of a lymphoid nature of Hodgkin and Reed-Sternberg cells and do not unequivocally exclude a derivation from other hematopoietic cells, extrapolation of the results from the in vitro cultures to the in vivo situation suggests a lymphoid (T or B cell) origin of these cells.