Interleukin-13 and interleukin-13 receptor in Hodgkin's disease: possible autocrine mechanism and involvement in fibrosis

Aims: Hodgkin's disease (HD) is characterized by the presence of Hodgkin and Reed-Sternberg (H-RS) cells against a hyperplastic background of reactive cells such as lymphocytes, histiocytes, plasma cells, eosinophils, neutrophils, and stromal cells. There is ample evidence to suggest that proliferation and survival of HD-derived cells is due to cytokine signalling. Recently, high expression of interleukin (IL)-13 was described in HD-derived cell lines. Here we investigated the possible involvement of IL-13 in the pathophysiology, especially autocrine pathways of H-RS cells. Methods and Results: The expression of IL-13 and IL-13 receptor (IL-13R) was determined by immunostaining and reverse transcriptase-polymerase chain reaction in 39 cases of HD, including 17 cases with nodular sclerosis (NS) type, 19 cases with mixed cellularity (MC), and three cases with lymphocyte predominance (LP) type. Expression of IL-13 was confined to H-RS cells and a few lymphocytes. IL-13R was expressed in H-RS cells, lymphocytes, histiocytes, fibroblasts, and endothelial cells. H-RS cells of MC and NS types frequently expressed both IL-13 and IL-13R. However the number of IL-13-positive H-RS cells was statistically higher in NS-type than in MC-type, but the number of IL-13R was similar. IL-13R-positive fibroblasts were frequently encountered in NS-type. H-RS cells of LP type rarely expressed IL-13. Conclusions: Our results suggest that IL-13 might be involved in autocrine pathways of H-RS cells and fibrosis at least in NS-type. Our results also indicated that in addition to the morphological and phenotypic differences, the neoplastic cells of LP type might be functionally different from H-RS cells of MC-and NS-types.