Evidence that Hodgkin and Reed-Sternberg cells in Hodgkin disease do not represent cell fusions

In most cases, Hodgkin and Reed-Sternberg (HRS) cells of classical Hodgkin disease (HD) carry rearranged immunoglobulin (Ig) genes and thus derive from B cells, In rare cases, HRS cells originate from T cells. However, based on the unusual immunophenotype of HRS cells, often showing coexpression of markers typical for different hematopoetic lineages, and the regular detection of numerical chromosomal abnormalities, it has been speculated that HRS cells might represent cell fusions, Five cases of HD with 2 rearranged IgH alleles were analyzed for the presence of additional IgH alleles in germline configuration as a potential footprint of a cell fusion between a B and a non-B cell. Similarly, one case of T-cell-derived HD with biallelic T-cell receptor beta (TCR beta) rearrangements was studied for the presence of unrearranged TCR beta alleles, In none of the 6 cases was evidence for additional IgH (or TCR beta) alleles obtained, strongly arguing against a role of cell fusion in HRS cell generation. (C) 2001 by The American Society of Hematology.