Eosinophil peroxidase is detectable with a monoclonal antibody in collagen bands of nodular sclerosis Hodgkin's disease.

An IgG2a murine monoclonal antibody derived against human eosinophils was shown to immunoprecipitate the 78,000 dalton form of human eosinophil peroxidase (EPO). To confirm the specificity of the antibody, we used a glucose-oxidase avidin biotin procedure to immunostain 32 human cell lines and tissues. An eosinophilic subline of HL-60 promyelocytic leukemia was the only cell type other than eosinophils to be recognized by the antibody. Because previous reports have described occult eosinophilic degranulation in tissues with a variety of pathological conditions, we immunostained cryostat sections of four consecutive lymph node biopsies of nodular sclerosis Hodgkin's disease with the monoclonal antibody. Our objective was to characterize by immunohistology the eosinophilic infiltration in a lymphoma that frequently contains substantial numbers of eosinophils. In all four cases of nodular sclerosis Hodgkin's disease, there was striking and extensive deposition of EPO in a dendritic pattern throughout the connective tissue and collagen bands. The extent of deposition of EPO in the bands far exceeded the degree of infiltration by intact eosinophils, as determined by examination of routinely stained tissue sections. A similar dendritic pattern was not observed in any of six benign lymph nodes that were immunostained for EPO. We conclude that the monoclonal antibody described in this report is specific for EPO and that eosinophils extensively degranulate and release EPO in the bands of nodular sclerosis Hodgkin's disease. Moreover, the degree of eosinophilic infiltration in this disorder cannot be assessed solely on the basis of intact eosinophils.