EXPRESSION OF CYTOTOXIC MOLECULE TIA-1 IN MALIGNANT-LYMPHOMAS MIMICKING FULMINANT-HEPATITIS

Involvement of malignant lymphoma in the liver inducing fulminant hepa tic failure has rarely been reported, Therefore, a close association b etween some lymphoma types with severe liver damage and the mechanism underlying the liver damage is intriguing. Three malignant lymphoma ca ses, which were clinically diagnosed as fulminant hepatitis, were coll ected from the autopsy records of Kawasaki Medical School (Kurashiki, Japan), All three cases were characterized by the presence of hepatosp lenomegaly without superficial lymph node swelling, high elevation of transaminase and lactate dehydrogenase (LDH; especially LDH-2), and a quite aggressive clinical course. Immunohistochemically, the tumor cel ls in all three cases were positive for T cell intracellular antigen ( TIA-1), which is a cytolytic protein in cytotoxic T and natural killer (NK) cells. The lymphomas were CD8(+) peripheral T cell lymphoma (cas e 1), CD56(+) T/NK cell lymphoma (case 2), and T cell lymphoma in a pa tient with mosquito hypersensitivity (case 3), Epstein-Barr virus infe ction was demonstrated on the tumor cells of cases 2 and 3 using an in situ hybridization method and those cases showed high titers of serum interferon-gamma and Fas. Frequent apoptosis of liver cells, where th e lymphoma cells had infiltrated, was revealed by a terminal deoxyribo syl transferase-mediated deoxyuridine nick end-labeling (TUNEL) method , The findings in this study suggest that fulminant hepatic injury is closely associated with cytotoxic molecule TIA-1 expression of the lym phoma cells and that some specific mechanism may be involved in liver damage.