Hodgkin's disease: an immunohistochemical and histological study.

The distribution of immunoglobulin (Ig) in Hodgkin's tissue has been demonstrated in paraffin and cryostat sections by the unlabelled antibody peroxidase-antiperoxidase (PAP) method and the two-stage fluorescein isothiocyanate (FITC)-based technique. The morphology and histogenesis of the Reed-Sternberg (RS) and Hodgkin (HD) cells has been studied with the metalophil method of Marshall (1948) and this revealed a population of dendritic histiocytes which corresponded in number, sizes and distribution to the RS and HD cells in adjacent sections stained by haematoxylin and eosin. The largest RS cells, however, appeared to be non-dendritic. A notable feature of Hodgkin's tissue was the tendency for the dendritic cells to form "nodules", in combination with a population of small lymphocytes. The PAP technique reveals Ig in the form of mu and delta heavy chains, as well as kappa and lambda light chains, in close association with and probably on the surface of a high proportion of these lymphocytes, suggesting that they are immature B cells. Similar reactions were given by the mantle of lymphocytes of surviving normal lymphoid follicles, and metalophil dendritic histiocytes were also demonstrated within the mantle and subjacent part of the germinal centre. Numerous immunocytes containing Ig were present in all lesions; in the majority of cases, more cells contained gamma than alpha or mu heavy chains, although in these cases alpha-positive cells outnumbered those containing gamma or mu heavy chains. In two-thirds of the cases, one-third of the RS cells contained cytoplasmic immunoglobulin. This was exclusively gamma heavy, although both light chains were present. In about half the cases a minority of the HD cells contained gamma chain. The results suggest that HD and RS cells are dendritic histiocytes of the type normally found in the lymphoid follicles and that their tendency to form nodules in assoication with B lymphocytes is a manifestatin of this origin. It is suggested that the presence of Ig most probably results from absorption of antigen-antibody complexes on the cell surface.