EXPRESSION OF INTERLEUKIN-1 RECEPTOR ANTAGONIST PROTEIN IN MALIGNANT-LYMPHOMAS - AN IMMUNOHISTOCHEMICAL STUDY

Objective.-Interleukin-1 (IL-1) receptor antagonist (IL-1ra) is a natu rally occurring modulator of IL-l that functions by competitively bind ing to IL-1 receptors without producing biologic effects. Interleukin- 1 is believed to be a mediator involved in production of constitutiona l symptoms in patients with malignant lymphoma. Because we know of no study regarding IL-1ra expression in lymphomas, we tried to demonstrat e the presence of IL-1ra in lymphomas using immunohistochemistry. Desi gn.-Anti-IL-1ra monoclonal antibody was applied to paraffin sections o f Hodgkin's disease and non-Hodgkin's lymphoma (NHL) with avidin-bioti n complex method. Results.-Interleukin-1 receptor antagonist was found to be present primarily in benign reactive histiocytes in neoplastic tissue. Positivity for IL-1ra was found in 12 (67%) of 18 cases of Hod gkin's disease and 53 (29%) of 184 cases of NHL. The positivity rate v aried in different subtypes of NHL. Three percent (1 in 30) of follicu lar small cleaved-cell lymphomas contained IL-1ra-expressing histiocyt es, whereas 52% (17 of 33) of diffuse mixed-cell and 27% (12 of 44) of diffuse large-cell lymphomas contained IL-1ra-positive histiocytes. N ine of 13 (69%) cases of high-grade NHLs contained IL-1ra-expressing h istiocytes. Among cases of NHL, the higher-grade NHL cases showed high er percentages of positivity. Conclusions.-The findings further suppor t the hypothesis that IL-1 may play a role in producing constitutional symptoms.