Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of cell-mediated cytotoxicity in the complex pathophysiology of graft-versus-host disease (GVHD) has remained poorly defined for several decades. We transplanted T cells from Fas-ligand (FasL)-defective and perforin-deficient mutant donor mice into lethally irradiated MHC-matched allogeneic recipient mice to characterize the role of cell-mediated cytotoxicity in GVHD. Although recipients of allogeneic FasL-defective donor T cells underwent severe GVHD-associated cachexia, they exhibited only minimal signs of hepatic and cutaneous GVHD pathology. Recipients of perforin-deficient allogeneic donor T cells developed signs of acute GVHD, but the time of onset was significantly delayed. These findings demonstrate that Fas-mediated anti-recipient cytotoxicity may be critical for the development of hepatic and cutaneous GVHD, but is not required for GVHD-associated cachexia. In addition, perforin-mediated anti-recipient cytotoxicity appears to play an important role in the kinetics of GVHD pathophysiology, but is not required for GVHD-associated tissue damage.
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PMID:The role of cell-mediated cytotoxicity in acute GVHD after MHC-matched allogeneic bone marrow transplantation in mice. 867 85

Fas (APO-1, CD95) is a type I integral membrane protein initially identified by mAbs that induce apoptotic cell death upon binding to certain tumor cells and its belongs to the TNFR family. Fas is expressed on activated lymphocytes and in various tissues including the liver, lung, intestine, and skin. Molecular cloning of Fas ligand (FasL) revealed that it is a type II integral membrane protein homologous to TNF. FasL is predominantly expressed on activated T and NK cells, and mediates Fas divided by target cell lysis by these effector cells. The Fas/FasL system has been also implicated in the pathogenesis of autoimmune diseases, fulminant hepatitis, GVHD, and AIDS. It has been recently reported that human FasL was released as a 26 kD soluble form from COS cells transfected with human FasL cDNA and activated human T cells. In this communication, metalloproteinase-mediated release of FasL and it's clinical relevance are discussed.
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PMID:[Metalloproteinase-mediated release of human fas ligand]. 874 61

Transfusion-associated graft-versus-host disease (TA-GVHD) is one of the most serious adverse effects of blood transfusion. It is generally thought to be caused by the infused lymphocytes. Donor-derived cytotoxic T lymphocytes (CTLs) directed against the recipient's HLAs, which have escaped the recipient's immune system and are proliferating, are considered to attack recipient organs and tissues. Despite the seriousness of the disease, the precise mechanism of its development remains unclear and no definitive treatment has been developed. With the aim of developing an effective treatment, we established and characterized T-cell clones from peripheral blood lymphocytes (PBLs) of a TA-GVHD patient. Three types of clones were established. Type I clones were CD8+ and specifically lyse cells that express HLA B52. Type II clones were CD4+, specifically lysed cells that express HLA DR15, and proliferated in response to stimulation with cells that express DR15. Type III clones were also CD4+, showed no cytotoxic activity toward any HLA-expressing cells, and proliferated in response to stimulation with cells that express DR15. Furthermore, we found that the Fas/Fas-ligand (Fas-L) system is involved in the cytotoxicity of the type I and II clones and that the type III clones produce and secrete a large amount of tumor necrosis factor beta (TNFbeta) after antigen stimulation. Based on our results, these three types of clones can be classified into two categories: those that have the ability to induce GVHD directly by cytolysis and that show no cytotoxic activity and those that have the ability to cause GVHD indirectly through secretion of cytotoxic lymphokines.
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PMID:Characterization of T-cell clones derived from peripheral blood lymphocytes of a patient with transfusion-associated graft-versus-host disease: Fas-mediated killing by CD4+ and CD8+ cytotoxic T-cell clones and tumor necrosis factor beta production by CD4+ T-cell clones. 902 68

The CD95 (APO-1/Fas) receptor mediates programmed cell death in apoptosis sensitive cells upon oligomerization either by CD95 antibody or by its natural ligand, CD95 ligand (CD95 L). Studies on tissue distribution have shown that CD95 is broadly expressed in normal adult tissues. Furthermore, the spectrum of CD95-expressing cells in inducibly enlarged in the context of chronic inflammation. In contrast, the number of cells capable of expressing CD95 L is strikingly limited to small subsets of lymphocytes and histiocytes and to some specialized normal epithelia. This suggests that cell death via this receptor/ligand system, although possible in almost every tissue and cell type, is limited to very special scenarios one of which is chronic lymphohistiocytic inflammation. The lpr/lpr mouse and the gld/gld mouse are well-known models for autoimmune disorders. Both mutants have abnormal B and T lymphocytes and high titers of autoantibodies. Recently, these mice have been discovered to have functional defects in the murine equivalents of human CD95 and CD95 L, respectively. This suggests that the CD95/CD95 L system might act by preventing autoimmune disease, e.g., by preventing emergence of autoreactive T and B lymphocytes. A human homologue of the lpr mutation has been described as autoimmune lymphoproliferative syndrome. We show that, in mice, CD95/ CD95 L might be operative in experimental graft versus host disease. Further, we suggest a role of this system in early steps of ulcerative colitis. Considering our observations against the background of current literature, CD95/CD95 L is likely to play a dual role in induction and maintenance of peripheral tolerance on the one hand and in tissue damage by chronic inflammation on the other.
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PMID:[CD95 (APO-1/Fas) and CD95-ligand (CD95L). Implications of these apoptosis mediating receptor/ligand systems in the pathogenesis of autoimmune diseases]. 906 94

The inability of B and T lymphocytes from mice expressing the lpr mutation to express functional Fas on their cell surface leads to an immunoregulatory defect associated with excessive autoantibody production. Nevertheless, T-dependent antibody response to foreign antigens in these mice appears relatively normal. To better understand exactly how Fas/FasL interactions control autoantibody production, studies were undertaken to determine (1) what kind(s) of B cells are sensitive to Fas-mediated apoptosis and (2) where the autoantibody-producing cells in lpr mice are located. We found that B cells activated by CD40L are extremely sensitive as targets in assays of Th1 CMC. However, B cells that receive a complete signal through their sIgM antigen receptor acquire a FasL-resistant phenotype. In situ analysis of splenic sections from lpr mice demonstrated that autoantibody-producing cells were uniquely localized to the T cell-rich inner PALS. A similar distribution pattern of IgG AFC was found in mice with chronic GVH disease. These data are consistent with the premise that the inner PALS, and not the germinal center, is the major site of FasL regulation of B cell activity and that, as a result of genetic or inducible loss of sensitivity to Fas-mediated apoptosis, autoreactive B cells may survive and differentiate in this location to cause serological autoimmunity.
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PMID:Unique site of autoantibody production in Fas-deficient mice. 918 58

Granzymes are neutral serine proteases that are stored in the specialized lytic granules of cytotoxic lymphocytes. A mutation introduced into the granzyme B locus leads to a severe defect in the ability of cytotoxic lymphocytes to induce apoptosis in susceptible target cells, and reduces the severity of class I-dependent acute graft-versus-host disease (GvHD). However, granzyme B-independent cytotoxicity also exists: in CD8+ cells, most of it is perforin-dependent, but in CD4+ cells, the Fas system and an additional pathway are involved. The identification of these pathways and their physiological relevance may lead to new approaches for inhibiting cytotoxic lymphocyte functions.
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PMID:The role of granzyme B cluster proteases in cell-mediated cytotoxicity. 919 23

Graft-versus-host disease (GvHD) is the major limiting toxicity of allogeneic bone marrow transplantation. T cells are important mediators of GvHD, but the molecular mechanisms that they use to induce GvHD are controversial. Three effector pathways have been described for cytotoxic T lymphocytes: one requires perforin and granzymes, the second Fas (APO-1; CD95) and its ligand. Thirdly, secreted molecules (e.g., TNF-alpha, gamma-IFN) can also mediate cytotoxicity. Together, these mechanisms appear to account for virtually all cytotoxicity induced by activated CTL in standard in vitro lytic assays. Using transplants across histocompatibility barriers, we were able to analyze the contributions of these effector molecules to cell-mediated cytotoxicity in vivo in a GvHD model. We found that Fas ligand is an important independent mediator of class II-restricted acute murine GvHD, while perforin/granzyme-dependent mechanisms have only a minor role in that compartment. In contrast, perforin/ granzyme-dependent mechanisms are required for class I-restricted acute murine GvHD, while Fas ligand is not. The perforin/granzyme pathway may therefore represent a novel target for anti-GvHD drug design. In support of this approach, we provide additional data suggesting that specific perforin/granzyme inhibitors should not adversely affect hematopoietic recovery after transplantation.
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PMID:Perforin/granzyme-dependent and independent mechanisms are both important for the development of graft-versus-host disease after murine bone marrow transplantation. 925 90

Transfusion-associated graft-versus-host disease (TA-GVHD) in immunocompetent patients is mediated by activated lymphocytes derived from the donor directed against host allogeneic HLA antigens. When considering this pathogenesis, the target of TA -GVHD treatment should be focused on the cytotoxic T cells (CTL) directed against host HLA. The combination therapy of anti-CD3 monoclonal antibody, OKT3, cyclosporin A, and corticosteroid may be effective to inhibit the cytotoxic activity of CTL. In addition to these immunosuppressive agents, monoclonal antibodies against functional cell surface molecules, such as LFA-1, ICAM-1, Fas, and Fas ligand, must be effective for treatment of TA-GVHD. Since the effective standard therapy of TA -GVHD has not been established, the prevention by gamma irradiation of cellular blood components is most important.
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PMID:[Treatment of transfusion-associated graft-versus-host disease]. 930 Dec 92

In vitro studies have demonstrated that intestinal intraepithelial lymphocytes (IEL) are constitutively cytotoxic; however, the mechanism and target of their cytotoxicity are unknown. Apoptosis of intestinal epithelial cells (IEC) and an increase in IEL numbers are classical signs of intestinal graft-versus-host disease (GVHD), although whether IEL can mediate IEC apoptosis directly in GVHD is unclear. Recent evidence suggests that target epithelial organ injury observed in GVHD is predominantly Fas-mediated; therefore, we investigated the possibility that IEL induce apoptosis of IEC through a Fas-mediated mechanism. Here, we demonstrate that the IEL isolated from normal mice readily display potent Fas ligand (FasL)-mediated killing activity after CD3 stimulation, and that IEC express Fas, suggesting that IEC are potential targets for FasL-mediated killing by IEL. In vitro, IEL isolated from GVHD mice have markedly increased FasL-mediated killing potential and are spontaneously cytolytic toward host-derived tumor cells predominantly through a Fas-mediated pathway. In vivo transfer of IEL isolated from GVHD mice induced significantly more IEC apoptosis in F1 wild-type mice than in Fas-defective F1lpr mice. Thus, these results demonstrate that FasL-mediated death of IEC by IEL is a major mechanism of IEC apoptosis seen in GVHD.
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PMID:Fas ligand- mediated killing by intestinal intraepithelial lymphocytes. Participation in intestinal graft-versus-host disease. 944 89

Graft-versus-host disease (GVHD) and infections are two major complications of allogeneic bone marrow transplantation (BMT). In the course of GVHD, one of the pathways that activated cytotoxic T cells use to execute their killing mechanisms is the Fas/Fas ligand pathway. This killing mechanism might be accompanied by the release of soluble Fas (sFas) in the circulation. To examine the association of serum sFas levels and post-BMT complications, we have analyzed sFas levels in sera of bone marrow recipients with and without GVHD. Postallogeneic BMT sFas levels were significantly increased during clinically relevant acute GVHD (aGVHD; P = .002). However, during infections sFas levels tended to decrease (P = .088). Yet, the simultaneous occurrence of GVHD and infections resulted in extreme high sFas levels. These results suggested that sFas release may be correlated with the amount of tissue damage, because aGVHD induces more damage than infections. The presence of significantly increased sFas levels during aGVHD provides new insights into the GVHD pathogenesis.
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PMID:Soluble Fas levels in sera of bone marrow transplantation recipients are increased during acute graft-versus-host disease but not during infections. 945 79


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