Bone Marrow Transplantation, (1999) 23, 1283–1289  1999 Stockton Press All rights reserved 0268–3369/99 $12.00 http://www.stockton-press.co.uk/bmt A metalloproteinase inhibitor prevents acute graft-versus-host disease in mice after bone marrow transplantation K Hattori 1 , T Hirano 1 , C Ushiyama 2 , H Miyajima 3 , N Yamakawa 4 , S Ikeda 5 , K Yoshino 5 , M Tateno 6 , K Oshimi 1 , N Kayagaki 4 , H Yagita 4,7 and K Okumura 4,7 1 Division of Hematology and 2 Division of Rheumatology, Department of Internal Medicine, 3 Division of Pathobiology, 4 Department of Immunology, Juntendo University School of Medicine, Tokyo; 5 New Drug Discovery Research Laboratory, Kanebo Ltd, Osaka; 6 Department of Pathology, Sapporo City General Hospital, Sapporo; and 7 CREST (Core Research for Evolutional Science and Technology) of Japan Science and Technology Corporation (JST), Tokyo, Japan Summary: Tumor necrosis factor (TNF) and Fas ligand (FasL) have been implicated in the pathogenesis of graft- versus-host disease (GVHD), which is a major compli- cation after allogeneic bone marrow transplantation. We have examined the ameliorating effect of a metallo- proteinase inhibitor (KB-R7785) that inhibits TNF-a and FasL release in a murine acute GVHD model after bone marrow transplantation. Administration of KB- R7785 to irradiated (BALB/c 3 C57BL/6) F1 mice that received C57BL/6 bone marrow cells and spleen cells reduced the mortality and weight loss in association with minimal signs of GVHD pathology in the liver, intestine, and hematopoietic tissues. The KB-R7785 treatment did not affect hematopoietic reconstitution by donor cells. Therefore, KB-R7785 could be a potent therapeutic agent for GVHD after bone marrow transplantation. Keywords: acute GVHD; TNF-a; Fas ligand; metallo- proteinase inhibitor Allogeneic bone marrow transplantation (BMT) has been a clinical treatment modality for hematopoietic disorders and hematologic malignancies. 1 The success rate of BMT has steadily increased in recent years, but graft-versus-host disease (GVHD) is still a major cause of post-transplant mortality. 2 An acute lethal form of GVHD is caused by activation of the host-reactive donor T cells as found in a murine model involving transfusion of C57BL/6 spleen cells into (DBA/2 3 C57BL/6)F1 or (BALB/c 3 C57BL/6)F1 mice. 3 Acute GVHD affects the skin, liver, gastrointestinal tract, and lymphoid tissues where inflam- matory reactions characterized by mononuclear cell infil- tration and histopathological damage take place, leading to erythroderma, diarrhea, wasting, and finally death. The effector mechanisms leading to the GVHD-associated tissue damage have not been fully clarified. Correspondence: Dr T Hirano, Division of Haematology, Internal Medi- cine Juntendo University School of Medicine, 2–1-1 Hongo, Bunkyo-ku, Tokyo 113, Japan Received 22 October 1998; accepted 19 January 1999 It is well known that the tumor necrosis factor (TNF)-a is an important cytokine in GVHD, and also in veno- occlusive disease (VOD) after human BMT. 4 It has been shown that serum levels of TNF-a are increased in patients undergoing GVHD after allogeneic BMT and that adminis- tration of anti-TNF-a antibody markedly reduced the weight loss and mortality in a mouse model of GVHD. 5 A clinical phase I–II study, using an anti-TNF-a monoclonal antibody (mAb) during pretransplant conditioning as an additive prophylaxis of acute GVHD after BMT, resulted in some beneficial effects. 6 Recently, the ligand for Fas (FasL) has also been impli- cated in the pathogenesis of GVHD. Fas (APO-1, CD95) is a member of the TNF receptor family and transmits an apoptotic cell death signal upon ligation by FasL. 7 Fas is expressed in various tissues, including the skin, liver and intestine which are target tissues of GVHD. 8 A critical involvement of FasL in the development of hepatic and cutaneous GVHD pathology has been demonstrated in a murine model of acute GVHD. 9 A partial contribution of FasL to mortality was also noted in a different murine model of acute GVHD. 10 We also recently demonstrated different contributions of TNF-a and FasL to GVHD patho- logies and a complete protection from mortality by neutralization of both TNF-a and FasL. 11 TNF-a and FasL are type II integral membrane proteins belonging to the TNF family and are predominantly expressed on activated macrophages and activated T cells, respectively. 12 It is known that TNF-a is efficiently shed from the macrophage surface as a soluble cytokine. Several recent studies have shown that some metalloproteinases mediate the processing of TNF-a which can be inhibited by hydroxamic acid-based metalloproteinase inhibitors. 13–17 We previously found that FasL is also efficiently released from the activated T cell surface and that some metalloproteinase inhibitors could inhibit shedding. 18 Moreover, we recently demonstrated a potent ameliorating effect of a metalloprote- inase inhibitor (KB-R7785), which inhibits the release of both TNF-a and FasL, in a lethal acute GVHD model where parental C57BL/6 splenocytes were injected into unirradiated (BALB/c 3 C57BL/6)F1 mice. 19 However, the beneficial effects of such a metalloproteinase inhibitor remain to be determined in a BMT model of acute GVHD which is more relevant to clinical situations. In this context,