The cellular origin and the type of proliferation of the Hodgkin and R
eed-Sternberg (HRS) cells, the malignant cells of Hodgkin's disease (H
D), is an issue of constant debate. Immunohistochemical and molecularb
iological studies of different research groups revealed contradictory
results among the different groups ranging from a complete absence to
a frequent presence of B-cell or T-cell characteristic features in the
HRS cells. The determination of their clonality by cytogenetic means
produced no conclusive results. To unequivocally clarify these questio
ns we and others isolated single HRS cells and amplified their immunog
lobulin (Ig) rearrangements. Most groups found Ig rearrangements withi
n the HRS cells pointing to a B-cell nature of these HD cases. Individ
ual IgH rearrangements were found in a proportion of the HD cases wher
eas most cases harbor monoclonal HRS cells with or without additional
polyclonal rearranged HRS cells. Further studies are needed to clarify
whether the differences among the different groups are caused by the
selection of the HD cases used for investigation.