Extensive deposition of eosinophil peroxidase in Hodgkin's and non-Hodgkin's lymphomas

To determine whether occult eosinophil degranulation occurs in lymphomas, the authors performed immunohistologic and cytochemical studies on cryostat sections from 25 consecutive lymph node biopsies. A glucose-oxidase immunohistochemical technique was employed with a murine monoclonal antibody specific for human eosinophil peroxidase (EPO). In 7 cases of Hodgkin's disease, 3 cases of T-immunoblastic sarcoma, and 1 case of small cleaved follicular center cell lymphoma with sclerosis, there was extensive and striking extracellular deposition of EPO in a granular and fibrillar pattern within the connective tissue. Similar degranulation of eosinophils was not observed in any of the benign lymph node specimens or other B-cell lymphomas. It is concluded that eosinophils extensively degranulate and release EPO in some types of lymphoma.