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

We studied the T cell repertoire and the mechanism of tolerance in two patients with severe combined immunodeficiency transplanted with HLA mismatched fetal liver stem cells. They are 17 and 5 years old now, healthy, and show normal immunoresponses to recall antigens. Their T cells are of donor origin, whereas monocytes and B cells remained of the host. The NK cells have different sources since in one patient they derive from the donor and in the other one from the host. Despite the HLA mismatch between donor and host cells, no acute or chronic graft-versus-host disease was observed. In vitro experiments with PBMC showed specific nonresponsiveness for the HLA antigens expressed by the host cells. However, an extensive clonal analysis showed that CD4+ and CD8+ host-reactive T cell clones recognizing class II and class I HLA molecules of the host, respectively, were present in the peripheral blood of both patients. Limiting dilution experiments indicated that the frequency of CD8+ host-reactive cells was in the same range as that observed for alloreactive T cells. In contrast, no donor reactive CD8+ T cells could be isolated. Host-reactive CD4+ and CD8+ T cell clones were normal in their capacity to produce IL-2, IFN-gamma, GM-CSF and IL-5, but they failed completely to synthesize IL-4. In addition, CD4+ T cell clones from patient RV secreted very high levels of IL-10. Interestingly, exogenous IL-10 was able to inhibit the proliferative responses of the CD4+ host-reactive T cell clones. Our data demonstrate that host-reactive cells are not deleted from the donor T cell repertoire following allogenic fetal liver stem cell transplantation. Therefore, in vivo tolerance between the host and the donor is maintained by a peripheral autoregulatory mechanism in which cytokines may play a role.
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PMID:T cell repertoire and tolerance after fetal stem cell transplantation. 135 21

Participation of IE antigens (Ag) in immune response as the transplantation Ag was examined. IE- B10.A(4R)(4R; Kk, IAk, IE-, Db) mice could not reject skin graft from IE Ag alone-disparate B10.A(2R) (2R; Kk, IAk, IEk, Db) mice despite intravenous (iv) injection of 2R spleen cells (SC) before or after skin grafting, indicating that graft rejection could not be caused across IE Ag-barrier alone. Furthermore, 4R SC could not induce lethal graft-versus-host disease (GVHD) in supralethally (950 rad) irradiated 2R mice. On the other hand, infiltration of lymphoid cells was observed at the site of transplanted 2R skin in 4R mice. SC of 4R mice unprimed or primed with 2R skin or 2R SC showed the capability to proliferate in vitro in response to 2R Ag. In immunofluorescence analysis of lymph node cells (LNC) of 4R mice injected iv with 2R SC 7 days earlier, IE-reactive CD4+Vbeta 11+ T cells did not change in number, but slightly increased the expression of interleukin-2 receptor (IL-2R). In 2R mice irradiated with 670 rad and injected iv with 4R SC 7 days earlier, 4R-derived CD4+V beta 11+ T cells proliferated, changed to blastoid form, and showed a markedly increased expression of IL-2R. To further investigate the influence of IE alloantigens on transplantation immunity, IL-2 production and anti-class I CTL activity were assayed. The 4R SC capable of recognizing IEk and Dk Ag of B10.BR (Kk, IAk, IEk, Dk) generated levels of both IL-2 and CTL activities higher than those of 2R SC capable of recognizing Dk Ag alone. These results strongly suggest that IE alloantigens indirectly act as the transplantation Ag by the stimulation of IE-reactive CD4+ helper T cells resulting in the differentiation of class I-restricted CD8+ T cells.
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PMID:Alloreactivity against IE-encoded antigens: evidence of the discrepancy between graft rejection and reactivity of IE-reactive T cells. 138 50

Lymphokine activated killer cells have potent antitumor effect both in vitro and in vivo. They have been reported to suppress bone marrow (BM) progenitor cell activity (PCA) in vitro, thus raising concern about the feasibility of their use after autologous bone marrow transplantation. The present study was carried out to evaluate the effect of LAK cells on BM engraftment in a syngeneic BMT setting in mice. LAK cells supplemented with or without exogenous interleukin-2 therapy did not impair the hematopoietic reconstitution or survival of mice undergoing BMT. LAK cells also did not reduce the PCA of the engrafted BM. LAK cell therapy did not cause graft-versus-host disease. Finally, LAK cells supplemented with IL-2 therapy improved the graft-versus-leukemia effect. These findings suggest that LAK cells plus IL-2 therapy after BMT does not impede hematopoiesis and should be evaluated as an adjuvant therapy with the aim of eradication of minimal residual disease after autologous BMT.
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PMID:Lymphokine-activated killer cells in autologous bone marrow transplantation. Evidence against inhibition of engraftment in vivo. 146 68

We suggest that acute GVHD after marrow transplantation reflects (1) host injury due to the conditioning regimen followed by the production of inflammatory cytokines; (2) stimulation of mature donor T cells in the milieu of increased cell surface expression of leukocyte adhesion molecules and HLA molecules, followed by the autocrine production of IL-2; and, finally, (3) recruitment and activation of additional mononuclear effector cells from donor marrow progenitors, which produce additional inflammatory cytokines, thus sustaining the response. The second step is critical for the amplification of the systemic inflammatory response, and it is absence in autologous, syngeneic, and T-cell-depleted transplants. These T cells may also contribute to the inflammatory cytokine network. Acute GVHD can occur in the absence of primary tissue injury in such settings as transfusion-related GVHD; however, it is likely that a greater HLA disparity between donor and host is required. We propose that inflammatory cytokine production is the final common pathway of acute GVHD. If this model is correct, control of cytokine dysregulation at any of several points should control GVHD. Further studies of GVHD and investigations of cytokine antagonists (eg, IL-4 or IL-10) or combinations of antagonists such as IL-1ra and soluble TNF receptor or pentoxifylline will allow us to determine the validity of this hypothesis.
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PMID:Cytokine dysregulation and acute graft-versus-host disease. 146 11

An immunotoxin containing the B-B10 MoAb, directed against the CD25 determinant, and the ribosome-inactivating protein saporin, inhibits 3H-TdR incorporation in phytohemagglutin, allogeneic-stimulated lymphocytes (primary and secondary mixed-lymphocyte reaction), and in an alloreactive T cell clone. A lower degree of inhibition was obtained with the B-B10 MoAb, which is known to inhibit IL-2 activity, as well as with the unconjugated compounds. These results suggest that the in vivo administration of the conjugate might be a more effective tool in the treatment of patients affected by graft-versus-host disease than B-B10 alone, by inducing an efficient killing of allogeneic-reacting T lymphocytes.
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PMID:B-B10 (anti-CD25)-saporin immunotoxin--a possible tool in graft-versus-host disease treatment. 149 46

Cyclosporin A (CsA) is a potent inhibitor of cytokine (IL-2-IL-6, IFN gamma) production by CD4+ T lymphocytes stimulated via the T cell antigen receptor pathway. This action results in indirect inhibitory effects on the growth and differentiation of B lymphocytes (IL-4 and IL-6). Using experimental models, it has also been shown that the functional activities of mononuclear phagocytes (IFN-gamma) and other antigen-presenting cells, production of mast cells (IL-3) and eosinophils (IL-5) and the activity of natural killer (NK) cells may be inhibited indirectly by CsA. In addition, however, CsA blocks B cell responses to Ca(2+)-dependent signals (e.g., anti-IgM) downstream of phosphatidyl inositol diphosphate hydrolysis; Ca(2+)-independent responses (e.g., to LPS or IL-4) are largely unaffected. In general terms, the functions of macrophages are unchanged or reduced in the presence of CsA. These include phagocytic activity in vitro and in vivo, chemotactic migration, superoxide and H2O2 production, protein (including monokine) secretion and MHC gene product expression. Antigen presentation (e.g., by epidermal Langerhans cells) may be affected, especially at high drug concentrations. There is recent evidence that CsA inhibits mediator (histamine and prostaglandin) release from human mast cells and that mucosal mast cell numbers may be diminished in CsA-treated animals exhibiting graft-versus-host disease or helminth infections.
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PMID:The effects of cyclosporin A on non-T cell components of the immune system. 150 9

Recent data in mice have shown that early administration of recombinant human interleukin-2 (rIL-2) provides significant protection from lethal graft-versus-host disease. Because of the potential clinical importance of these findings, it will be important to assess the effectiveness of this therapy in a large animal preclinical bone marrow transplantation model. We report here our initial studies of the in vitro and in vivo effects of rIL-2 in miniature swine. In vitro 4-day cultures of pig peripheral blood lymphocytes (PBL) in complete medium containing rIL-2 at 1,000 U/ml resulted in optimal proliferation and generation of lymphokine-activated killer (LAK) cells. A pig-mouse hybridoma cell line was found to be highly sensitive as a LAK cell target. Two naive pigs received 20,000 U/kg and 2 pigs received 100,000 U/kg of rIL-2 intravenously twice a day for 4 days. No clinical symptoms were seen during or after administration at the lower dose while both high dose-treated animals showed generalized erythema from days 2 to 4, and one showed mild diarrhea during this period. The disappearance of IL-2 activity from the serum showed two components: (1) an initial fast component with a half-time of approximately 10 min and (2) a slow component with a half-time of approximately 60 min. LAK cell precursors disappeared from the peripheral circulation by 6 min after rIL-2 administration and began to recover by 6 h in the low dose recipients and only after 12 h in the high dose recipients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:In vitro and in vivo effects of recombinant human interleukin-2 in naive miniature swine. 151 21

Despite major advances, graft-versus-host disease (GVHD) remains a major obstacle to clinical bone marrow transplantation. Prophylaxis by T cell depletion is associated with increased rates of engraftment failure and leukemic relapse. Treatment with high-dose IL-2 can markedly protect lethally irradiated mice from GVHD-related mortality, especially when T cell-depleted (TCD) syngeneic bone marrow cells (BMC) are co-administered. In these IL-2-protected animals, allogeneic reconstitution is observed, and a graft-versus-leukemia effect of allogeneic T cells is preserved. To determine whether IL-2 might increase alloresistance under conditions in which alloengraftment is more difficult to achieve, we have now evaluated the possible effect of IL-2 on: (1) competitive repopulation of lethally irradiated mice by mixtures of TCD allogeneic and TCD syngeneic BMC; (2) radiation protection by TCD allogeneic BMC; (3) timing of hematologic recovery; and (4) allogeneic engraftment in sublethally irradiated recipients. The results show that IL-2 has only a limited and strain-restricted effect on alloengraftment. This effect may reflect activation of alloresistant host natural killer cells, a cell population which is not essential for the protective effect of IL-2 against GVHD.
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PMID:Alloengraftment in IL-2-treated mice. 152 5

Natural suppressor (NS) cells, which nonspecifically suppress immune responses, are present in the spleen following exposure to radiation, chronic graft-versus-host disease, or cancer and in normal bone marrow. A model system is described which allows the study of cytokines activating and inhibiting NS cells, cytokines mediating NS activity, and NS effects on cytokine synthesis. Recombinant interleukin-3 (rIL-3) and granulocyte-macrophage colony-stimulating factor (rGM-CSF) efficiently activated NS cells present in normal bone marrow and were effective at concentrations as low as 5 U/ml. At high concentrations, GM-CSF, but not IL-3, did not activate NS cells. Recombinant interferon-gamma (rIFN-gamma) blocked the activation of bone marrow NS cells by rIL-3, but did not down-regulate NS cells once activated. The NS cells secreted one or more soluble suppressor factors, which blocked IL-2 synthesis and also inhibited IL-2-dependent T cell proliferation in the presence of excess IL-2.
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PMID:Cytokine regulation of bone marrow natural suppressor cell activity in the suppression of lymphocyte function. 153 70

We have recently demonstrated that high-dose IL-2, when begun on the day of bone marrow transplantation, has a potent protective effect against graft-vs.-host disease mortality, especially when coadministered with T cell-depleted syngeneic bone marrow cells. Because several groups of investigators have demonstrated that lymphokine-activated killer cells can mediate GVHD protection, we hypothesized that the mechanism of protection by IL-2 administration might involve the in vivo activation of natural killer and/or LAK cells. In order to test this hypothesis, we evaluated the effect of IL-2 administration on the number of NK1+ cells and on NK-mediated cytotoxic activity in recipients of GVHD-producing inocula. Furthermore, we evaluated the effects on IL-2-induced GVHD protection of depleting NK cells and LAK precursor cells in vivo with mAb against NK1.1 or antiserum against asialo GM1. The results demonstrate that: (1) The number of NK1+ cells is not increased in spleens of IL-2-treated compared with control recipients of GVHD-producing inocula; (2) NK activity is not increased in IL-2-treated compared with control recipients of GVHD-producing inocula during or immediately following the period of IL-2 administration; (3) depletion of NK cells and LAK precursors from the donor and host influenced the time course of GVHD-related mortality in a complex fashion; and (4) IL-2-induced GVHD protection is largely independent of the activity of an NK or LAK cell population of donor or host origin. IL-2-induced GVHD protection therefore reflects primarily the activity of non-LAK protective cell populations, or it may be a direct inhibitory effect on responding donor cell populations as they encounter host antigen.
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PMID:The mechanism of IL-2-mediated protection against GVHD in mice. II. Protection occurs independently of NK/LAK cells. 153 68


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