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 bcl-2 gene family plays a significant role in the propagation of cell survival and tissue modeling. Bcl-2 was originally described in follicular lymphomas and is associated with the suppresion of cellular apoptosis. Evaluation for this protein has been performed for a variety of benign and malignant cutaneous tumors but not to any significant extent on inflammatory disorders. Therefore, we stained biopsy specimens from diseases with interface inflammation (lichen planus, acute graft-versus-host disease, and erythema multiforme) for Bcl-2. Epidermal expression of this protein was minimal for all three diseases; however, lymphocytes stained prominently in lichen planus. The data suggest that Bcl-2 is not prominently involved in the epidermal changes in these diseases. The role of other members of this oncogene family in interface dermatitis still needs to be elucidated.
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PMID:Expression of bcl-2 in lichen planus, acute graft-versus-host disease, and erythema multiforme. 905 54

Graft versus host disease (GVHD) occurs in up to 75% of patients who have had an allogeneic bone marrow transplant (BMT). However, the pathophysiology of this disorder, including the mechanisms responsible for enhanced apoptosis, are poorly understood. Bcl-2 is a cellular protein known to inhibit apoptosis in a variety of human tissues. Therefore, the aim of this study was to evaluate the expression of Bcl-2 in colonic GVHD and to determine its relationship to cell proliferation and apoptosis in this disease. Routinely processed colonic mucosal biopsy specimens from 47 allogeneic BMT patients with diarrhea were evaluated histologically for the grade of GVHD (0-4) and for the degree of apoptosis (apoptosis index). Immunohistochemical staining for Bcl-2 and MIB-1, a cell proliferation marker, was performed, and the results were correlated with the histological findings and with each other. Normal-appearing colonic mucosal biopsy specimens from 10 age-matched patients with noncolonic diarrhea served as controls. Also evaluated were 13 colonic biopsy specimens from 13 patients with chronic ulcerative colitis (three inactive, four mild chronic-active, six moderately severe chronic active) to test the specificity of our findings. When compared with controls, a slight trend toward increased Bcl-2 expression was noted in patients with high-grade GVHD (grade 3 or 4) (P=.09). However, Bcl-2 expression did not correlate with the degree of apoptosis in these patients. In contrast, the degree of Bcl-2 staining correlated positively with the crypt proliferative rate (P=.04). Furthermore, crypt proliferation was significantly higher in the GVHD patients in comparison with controls (MIB-1 index, 27.7+/-17.1 v 15.6+/-11.4, =.02), and increased progressively with each successively higher grade of GVHD, and with the degree of apoptosis. Similar to GVHD, Bcl-2 expression was increased in biopsy specimens of CUC patients with higher grades of active injury and epithelial regeneration. This immunohistochemical study does not provide support for Bcl-2 in the pathogenesis of GVHD-induced apoptosis in the colon, but instead, indicates that this protein may play a nonspecific role in the generalized response to cellular injury in GVHD.
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PMID:Relationship of Bcl-2 expression with apoptosis and proliferation in colonic graft versus host disease. 971 31

Allogeneic hematopoietic stem cell transplantation (AHSCT) leads to a prolonged state of immunodeficiency characterized by low peripheral naive T-cell counts. To identify the mechanisms leading to this defect we quantitatively and qualitatively analyzed thymic function through quantification of T-cell receptor excision circle (TREC) frequencies (both the signal-joint TREC [sjTREC] and 6 different DbetaJbeta TRECs, by-products of T-cell receptor [TCR] alpha and beta gene rearrangement, respectively), in conjunction with immunophenotype and spectratype analyses in a cohort of patients sampled from 1 to 10 years following AHSCT. In this cohort, reduced thymic function was associated only with ongoing clinical chronic graft-versus-host disease (cGVHD). Nonetheless, the diversity of thymic production remained unchanged irrespective of the patient's cGVHD status. Interestingly, increased homeostatic proliferation was found in the naive T-cell compartment of cGVHD- patients who underwent transplantation. However, reduced expression of both the interleukin-7 receptor alpha (IL-7Ralpha) (CD127) chain and the antiapoptotic protein Bcl-2 was observed. Taken together, these data indicate that the inability to reconstitute the naive T-cell compartment for several years after AHSCT, in the absence of cGVHD, is a consequence of impaired naive T-cell survival rather than thymic dysfunction.
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PMID:Evidence for adequate thymic function but impaired naive T-cell survival following allogeneic hematopoietic stem cell transplantation in the absence of chronic graft-versus-host disease. 1293 79

Interleukin-15 (IL-15) is a gamma-common cytokine that plays an important role in the development, survival, and proliferation of natural killer (NK), NK T, and CD8+ T-cells. We administered IL-15 to recipients of an allogeneic bone marrow transplantation (allo BMT) to determine its effects on immune reconstitution. Posttransplantation IL-15 administration significantly increased donor-derived CD8+ T (mostly CD122(+)CD44(+)CD8+ T-cells), NK, and NK T-cells at day +28 in young and old recipients of allo BMT. This was associated with enhanced T-cell and NK-cell function. IL-15 stimulated homeostatic proliferation of donor CD8+ T-cells in recipients of carboxyfluorescein diacetate succinimidyl ester-labeled donor T-cell infusions. Posttransplantation IL-15 administration also resulted in a decrease in apoptotic CD8+ T-cells, an increase in Bcl-2-expressing CD8+ T-cells, and an increase in the fraction of Ki67+ proliferative NK and CD8+ T-cells in recipients of allo BMT. IL-15 did not exacerbate graft-versus-host disease (GVHD) in recipients of T-cell-depleted BMT but could aggravate GVHD in some cases in recipients of a T-cell-repleted BMT. Finally, we found that IL-15 administration could enhance graft-versus-leukemia activity. In conclusion, IL-15 can be administered safely to recipients of a T-cell-depleted allo BMT to enhance CD8+ T, NK, and NK T-cell reconstitution.
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PMID:Interleukin-15 enhances immune reconstitution after allogeneic bone marrow transplantation. 1528 Feb 5

Graft-versus-host disease (GVHD) is caused by alloreactive donor T cells that trigger host tissue injury. GVHD develops over weeks or months, but how this immune response is maintained over time is unknown. In mouse models of human GVHD, we identify a new subset of postmitotic CD44(lo)CD62L(hi)CD8(+) T cells that generate and sustain all allogeneic T-cell subsets in GVHD reactions, including central memory, effector memory and effector CD8(+) T cells, while self-renewing. These cells express Sca-1, CD122 and Bcl-2, and induce GVHD upon transfer into secondary recipients. The postmitotic CD44(lo)CD62L(hi)CD8(+) T cells persist throughout the course of GVHD, are generated in the initial phase in response to alloantigens and dendritic cells and require interleukin-15. Thus, their long life, ability to self-renew and multipotentiality define these cells as candidate memory stem cells. Memory stem cells will be important targets for understanding and influencing diverse chronic immune reactions, including GVHD.
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PMID:Host-reactive CD8+ memory stem cells in graft-versus-host disease. 1633 66

Induction of apoptosis and changes to cytokine secretion patterns have been implicated in the mechanism of action of extracorporeal photopheresis (ECP). Lymphocyte apoptosis is initially detected in significant numbers prior to re-infusion and by 48 h post-ECP the majority of treated lymphocytes are apoptotic. The early apoptosis involves changes to mitochondrial function, reversal of the Bcl-2/Bax ratio and externalisation of phosphatidylserine. Apoptotic lymphocytes, observed from 20 h post-ECP, are associated with enhanced levels of CD95 and Fas-ligand. For cutaneous T cell lymphoma (CTCL), processing of the apoptotic lymphocytes, by suitable antigen presenting cells (APCs), is suggested to induce a clonal cytotoxic response which targets the malignant T cell population. Increased levels of TNFalpha and IFNgamma, observed post-ECP in monocytes and lymphocytes, respectively, are thought to further contribute to the proposed anti-tumour reaction seen in CTCL. However, down-regulation of pro-inflammatory cytokines and enhanced anti-inflammatory responses have been reported following ECP treatment. These immune responses may contribute to the tempering of the inflammatory conditions, such as graft versus host disease, which respond to ECP. Furthermore, untreated monocytes exposed to ECP-treated lymphocytes have also demonstrated a shift in monocyte cytokine-secretory pattern, toward one associated with immune tolerance. Recently, a mechanism of ECP-induced immune tolerance has been linked to the stimulation of the anti-inflammatory cytokines IL10 and TGFbeta by T regulatory cells, following the infusion of ECP-treated CD11c(+) APCs. Ultimately, the multifaceted responses, induced by ECP, may explain the diversity of clinical conditions that benefit.
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PMID:Extracorporeal photopheresis: a focus on apoptosis and cytokines. 1679 26

Delayed T-cell recovery is an important complication of allogeneic bone marrow transplantation (BMT). We demonstrate in murine models that donor BM-derived T cells display increased apoptosis in recipients of allogeneic BMT with or without GVHD. Although this apoptosis was associated with a loss of Bcl-2 and Bcl-X(L) expression, allogeneic recipients of donor BM deficient in Fas-, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)- or Bax-, or BM-overexpressing Bcl-2 or Akt showed no decrease in apoptosis of peripheral donor-derived T cells. CD44 expression was associated with an increased percentage of BM-derived apoptotic CD4(+) and CD8(+) T cells. Transplantation of RAG-2-eGFP-transgenic BM revealed that proliferating eGFP(lo)CD44(hi) donor BM-derived mature T cells were more likely to undergo to apoptosis than nondivided eGFP(hi)CD44(lo) recent thymic emigrants in the periphery. Finally, experiments using carboxyfluorescein succinimidyl ester-labeled T cells adoptively transferred into irradiated syngeneic hosts revealed that rapid spontaneous proliferation (as opposed to slow homeostatic proliferation) and acquisition of a CD44(hi) phenotype was associated with increased apoptosis in T cells. We conclude that apoptosis of newly generated donor-derived peripheral T cells after an allogeneic BMT contributes to delayed T-cell reconstitution and is associated with CD44 expression and rapid spontaneous proliferation by donor BM-derived T cells.
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PMID:Rapidly proliferating CD44hi peripheral T cells undergo apoptosis and delay posttransplantation T-cell reconstitution after allogeneic bone marrow transplantation. 1881 89

Although it is well known that in vivo radiation depletes immune cells via the Bcl-2 apoptotic pathway, a more nuanced analysis of the changes in the balance of immune-cell subsets is needed to understand the impact of radiation on immune function. We show the balance of T-cell subsets changes after increasing single doses of total body irradiation (TBI) or after fractionated irradiation of the lymphoid tissues (TLI) of mice due to differences in radioresistance and Bcl-2 expression of the NKT-cell and non-NKT subsets to favor CD4(+)Bcl-2(hi) NKT cells. Reduction of the Bcl-2(lo) mature T-cell subsets was at least 100-fold greater than that of the Bcl-2(hi) subsets. CD4(+) NKT cells upregulated Bcl-2 after TBI and TLI and developed a Th2 bias after TLI, whereas non-NKT cells failed to do so. Our previous studies showed TLI protects against graft versus host disease in wild-type, but not in NKT-cell-deficient mice. The present study shows that NKT cells have a protective function even after TBI, and these cells are tenfold more abundant after an equal dose of TLI. In conclusion, differential expression of Bcl-2 contributes to the changes in T-cell subsets and immune function after irradiation.
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PMID:Differences in Bcl-2 expression by T-cell subsets alter their balance after in vivo irradiation to favor CD4+Bcl-2hi NKT cells. 1919 37

Adult T-cell Leukemia (ATL) is an aggressive malignant disease of CD4+ T-cells associated with human T-cell leukemia virus type I (HTLV-I). Prognosis of ATL patients is directly correlated to the subtype of ATL. Treatment of the aggressive forms (acute and lymphoma types) of ATL remains inadequate, as most ATL patients receive conventional chemotherapy without stem cell rescue. At present, LSG15 is the standard chemotherapy for the treatment of aggressive ATL, but the efficacy of LSG15 in most patients is transient. To prolong median survival time, additional therapies for maintenance of complete response (CR) are needed after achieving CR by induction chemotherapy. Improved outcome after allogeneic stem cell transplantation (allo-SCT), despite a high incidence of graft-versus-host disease, has been reported. Thus, allogeneic bone marrow transplantation and allogeneic peripheral blood SCT may have great potential for eradication of HTLV-1 and cure of ATL. Recently, reduced-intensity conditioning stem cell transplantation was also reported to be effective for ATL. Although several issues, including selection criteria for patients and sources of stem cells remain to be resolved, allo-SCT may be considered as a treatment option for patients with aggressive ATL. To evaluate whether allo-SCT is more effective than the standard chemotherapy (LSG15) for aggressive ATL, an up front phase II clinical trial of JCOG-LSG is now being planned. Novel innovative targeted strategies, such as antiretroviral therapy, arsenic trioxide, nuclear factor-kappaB inhibitors, proteasome inhibitors, histone deacetylase inhibitors, several monoclonal antibodies including anti-CC chemokine receptor 4, anti-folate, purine nucleotide phosphorylase inhibitor, mTOR (mammalian target of rapamycin) inhibitor, bendamustine, small molecule Bcl-2 inhibitors and Tax-targeted immunotherapy, should be promptly studied in order to develop curative treatments for ATL in the near future.
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PMID:Treatment of adult T-cell leukemia. 2050 72

CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg) play an important role in the control of chronic graft-versus-host disease (cGVHD). In this study, we examined telomere length and telomerase activity of Treg and conventional CD4(+) T cells (Tcon) in 61 patients who survived more than 2 years after allogeneic hematopoietic stem cell transplantation. Cell proliferation and expression of Bcl-2 were also measured in each subset. Treg telomere length was shorter and Treg telomerase activity was increased compared with Tcon (P < .0001). After transplantation, Treg were also more highly proliferative than Tcon (P < .0001). Treg number, telomerase activity, and expression of Bcl-2 were each inversely associated with severity of cGVHD. These data indicate that activation of telomerase is not sufficient to prevent telomere shortening in highly proliferative Treg. However, telomerase activation is associated with increased Bcl-2 expression and higher Treg numbers in patients with no or mild cGVHD. In contrast, patients with moderate or severe cGVHD have fewer Treg with lower levels of telomerase activity and Bcl-2 expression. These results suggest that failure to activate Treg telomerase may restrict proliferative capacity and increase apoptotic susceptibility, resulting in the loss of peripheral tolerance and the development of cGVHD.
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PMID:Low telomerase activity in CD4+ regulatory T cells in patients with severe chronic GVHD after hematopoietic stem cell transplantation. 2190 Jan 96


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