Hodgkin's disease (HD) is a lymphoid malignancy characterized by the presence of Reed-Sternberg (RS) and Hodgkin's cells in a background of mixed inflammatory cells and stromal reaction. Studies have documented that HD is a neoplasm associated with abnormal cytokine and chemokine production. To define the expression of macrophage-derived chemokine (MDC) in HD, 57 cases (18 lymphocyte predominant, 11 mixed cellularity, 28 nodular sclerosis) were stained for MDC by immunohistochemistry and compared with reactive lymph nodes as controls. MDC was expressed by RS cells in classical HD (CHD) and showed a distinct cytoplasmic and Golgi localization. Accumulating evidence suggests that lymphocyte-predominant HD (LPHD) represents an entity distinct from CHD, with different biological properties and clinical course. On the basis of the high level of MDC staining alone, CHD could be distinguished from LPHD (P <.001), which showed only faint staining of scattered histiocytes similar to control tissues. CHD cases with high MDC mRNA levels showed high levels of MDC protein expression by immunohistochemistry (P <.001) and significant eosinophil infiltration, suggesting that MDC may represent another molecule that plays a critical role in eosinophil recruitment. We also analyzed 102 cases of non-Hodgkin's lymphoma and normal spleen, lymph node, and thymic tissue. High levels of MDC expression were specific to CHD cases because only low levels of MDC were observed in a minor subset of LPHD, NHL or normal lymphoid tissues.