Background: The nodular sclerosis and mixed cellularity subtypes of Hodgkin
's disease are histologically characterised by a small population of neopla
stic cells, the so-called Reed-Sternberg cells and their mononuclear varian
ts (RS cells) and an extensive admixture of other cell types including lymp
hocytes, plasma cells, eosinophils, and histiocytes. The nature of this inf
iltrate is largely known, but the mechanisms and functional effects are not
. The small lymphocytes immediately surrounding the RS cells are mostly CD4
+ T cells that express early activation markers. The absence of prominent s
pecific cytotoxic I cell or natural killer (NK) cell populations seems to a
rgue against a Th1-type response, whereas the sometimes prominent admixture
of plasma cells and eosinophils is suggestive of a Th2-type response. Enri
chment of the CD4 T-cell population may result from selective influx of CD4
T cells or from selective depletion of CD8 cells and NK cells.
Results and discussion: The T cells surrounding RS cells have an immuno-phe
notype and cytokine production capability consistent with a Th2-type respon
se. RS cells express several members of the TNF receptor family such as the
FAS ligand (CD95L) that may induce apoptosis of activated, FAS expressing,
CD8+ T cells and NK cells. The RS cells also produce TGF beta and interleu
kin-10 that may downmodulate the Th1 response. In addition, the Reed-Sternb
erg cells produce the chemokine TARC that could lead to the specific attrac
tion of a Th2 I-cell subset.
Conclusion: RS cells have several mechanisms that may allow it to escape an
effective immune response. The relative contributions of each of these and
other potential mechanisms are not yet known.