IgE, Reed-Sternberg cells, and eosinophilia in Hodgkin's disease

Tissues containing Hodgkin's disease tumors of the nodular sclerosis and mixed cellularity subtypes are frequently infiltrated by numerous degranulating eosinophils that release granule proteins such as eosinophil peroxidase and major basic protein. Until recently, the causes of the eosinophil infiltration and degranulation in Hodgkin's disease tumors were unknown. Analysis of Hodgkin's disease tissues by a sensitive and specific immunoperoxidase technique has now demonstrated the extensive presence of IgE in the Reed-Sternberg cells and adjacent cells of Hodgkin's disease tumors. Because eosinophils express a cell-surface receptor (CD23) for IgE and degranulate in the presence of IgE deposits, the extensive eosinophilia that is frequently present in Hodgkin's disease tumors is, at least in part, attributable to the IgE deposits within the tumor. In this review, we discuss the possible mechanisms and biological significance of IgE-related eosinophilia in Hodgkin's disease.