MIP-1 alpha expression in tissues from patients with hemophagocytic syndrome

Hemophagocytic syndrome (HPS) is a clinicopathologic syndrome that can be p recipitated by a variety of causes and is characterized by a systemic activ ation of macrophages, which are induced to undergo phagocytosis. Chemokines play an important role in the inflammatory cell recruitment into tissues. We examined the expression of chemokines and cytokines in tissues exhibitin g histologic evidence of HPS in a variety of settings: peripheral T-cell ly mphoma, three patients; nasal T/NK cell lymphoma, one patient; subcutaneous panniculitis-like T-cell lymphoma, one patient; and chronic EBV infection, one patient. Compared with control tissues, we found elevated macrophage i nflammatory protein-alpha (MIP-1 alpha) and interferon-gamma (IFN-gamma) ex pression, but not macrophage-derived chemotactic factor (MDC) or TNF-alpha, in tissues of patients with HPS irrespective of the cause or setting. MIP- 1 alpha can promote macrophage chemotaxis and IFN-gamma promotes macrophage activation. Elevated expression of IP-10 and monokine induced by IFN-gamma (Mig) was also detected in tissues exhibiting features of HPS, providing a n explanation for the occurrence of chemoattraction of T-cells and NK cells . Immunohistochemical analysis of tissues with evidence of phagocytic activ ity in that site showed MIP-1 alpha characteristically localized to endothe lial cells of blood vessels and splenic sinuses, lymphocytes, and macrophag es. These results provide evidence for MIP-1 alpha chemokine expression in tissues from patients with HPS and suggest that MIP-1 alpha may play an imp ortant role in the pathogenesis of the hemophagocytic syndrome.