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 fro m 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 detect ion 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 germli ne 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-cel l receptor beta (TCR beta) rearrangements was studied for the presence of u nrearranged TCR beta alleles, In none of the 6 cases was evidence for addit ional IgH (or TCR beta) alleles obtained, strongly arguing against a role o f cell fusion in HRS cell generation. (C) 2001 by The American Society of H ematology.