Biomedical subjects

Y Z Jiang

Publications and source records attributed to Y Z Jiang.

At least 19 recordsLinked to original sources

PubMed2000

Thyroid storm presenting as multiple organ dysfunction syndrome.

Thyroid storm is a rare disorder characterized by hypertension, hyperthermia, and multiple systems involvement. Early recognition and treatment of thyroid storm are essential in reducing morbidity and mortality from this disorder. We present the case of a patient with an atypical (normothermic, normotensive) presentation of thyroid storm, accompanied by multiple organ dysfunction syndrome, including lactic acidosis and liver dysfunction, both of which are very rare complications. This case highlights both the multiple organ systems that can be involved in thyroid storm and the importance of recognizing atypical presentations of thyroid storm.

Adult↗

PubMed2000

Pain as a mutual experience for patients, nurses and families: a perspective from Shanghai, China.

The author of this article visited China for the purpose of helping the faculty of the School of Nursing learn research skills by participating in research--a kind of learn by doing. Both investigators had conducted quantitative studies in the US--one with children and one with adults--that were adapted for use in China. Seeking to also include a qualitative study, the investigators explored several possible research areas. Because pain is a universal phenomena, it was chosen as the subject for the study using the qualitative methodology reported in the first part of this article.

Adult↗

PubMed1999

A technique for dual determination of cytotoxic and helper lymphocyte precursor frequency by a miniaturized dye release method.

Helper (HTLPf) and cytotoxic (CTLPf) lymphocyte precursor frequency assays are increasingly used in bone marrow stem cell and organ transplant compatibility testing. Current techniques require large cell numbers and radioisotopes. To improve the technique, we developed a miniaturized fluorescent read-out combined HTLPf/CTLPf limiting dilution assay. The assay requires only 5 x 10(6) stimulators, 2 x 10(6) responders and 0.24 x 10(6) target cells in Terasaki plates (40 microl/well). For the HTLPf, culture supernatants from each well were assayed for IL-2 production. The IL-2-dependent proliferation of the mouse 9.12 cell line was detected by a semi-automated fluorescent dye technique. After addition of rhIL-2 (recombinant human IL-2) on days 3 and 7, CTLPs were detected on day 10 by measuring the lysis of dye-labeled targets. Results were comparable to standard radioisotope-based techniques. The assay had a coefficient of variation of approximately 30%. The assay detected helper CD4 cells, pure cytotoxic CD8, helper CD8 cells and helper/cytotoxic CD8 cells. Discrimination was demonstrated between HLA-matched related and non-related pairs. The ease of testing and small cell numbers required should facilitate further evaluation of HTLPf and CTLPf for compatibility testing in unrelated donor transplantation and monitoring immune responses following adoptive transfer of lymphocytes.

Animals↗

PubMed1999

Human G-CSF-mobilized CD34-positive peripheral blood progenitor cells can stimulate allogeneic T-cell responses: implications for graft rejection in mismatched transplantation.

To investigate mechanisms of stem cell graft rejection we studied the allo-stimulatory potential of G-CSF mobilized peripheral blood progenitor cells (PBPC). CD34+ cells were purified (>95%) in a two-step procedure using immunoaffinity columns for CD34 selection and T-depletion. The capacity of CD34+ cells to stimulate allogeneic T-cell responses was compared with other cells from the same individual. CD34+ cells induced potent proliferative responses at stimulator:responder ratios of 1:20, but were approximately 50-fold less efficient compared to dendritic cells. Furthermore, CD34+ cells primed responses from partially matched allogeneic T cells in bulk cultures. Dual-colour flow cytometry showed that the co-stimulatory molecules B7.1, CD40 and ICAM-1 were absent on resting CD34-positive progenitor cells, but were induced during incubation with allogeneic lymphocytes due to a cytokine-mediated effect. Up-regulation of accessory molecules on CD34+ cells was reproduced by incubation with interferon-gamma or GM-CSF which enhanced the allo-stimulatory activity of CD34+ cells. Blocking studies with inhibitory antibodies suggested co-stimulatory functions for B7.2, ICAM-3, CD40 and LFA-3. CD34+ cells were more efficient in inducing allogeneic T-cell responses when compared to the unprocessed leukapheresis products. The reduced allo-stimulatory ability of G-CSF mobilized PBPC could be explained by the presence of CD3+ 4+ and CD3+ 8+ lymphocytes with suppressor activity. We conclude that current methods of stem cell selection for transplantation do not avoid allosensitization of the recipient and that further graft manipulation with add-back of lymphocytes or selection of subsets of CD34+ cells with reduced allo-stimulatory ability may reduce graft rejection.

Antibodies, Blocking↗

PubMed1998

Specific depletion of alloreactive T cells in HLA-identical siblings: a method for separating graft-versus-host and graft-versus-leukaemia reactions.

Accumulating evidence indicates that alloreactive donor T cells confer both graft-versus-host (GVH) and graft-versus-leukaemia (GVL) reactivity following allogeneic bone marrow transplantation. We have developed a method to deplete alloreactive donor T cells with an immunotoxin targeting the alpha chain of the IL-2 receptor. In patients with chronic myeloid leukaemia and their HLA-identical sibling donors, we measured donor helper T-lymphocyte precursor frequencies (HTLPf) against recipient peripheral blood mononuclear cells (PBMNC; donor versus host), recipient leukaemia cells (donor versus leukaemia) and third-party PBMNC, before and after the depletion. In seven pairs there was a 4.3-fold reduction of donor-versus-host HTLPf (P=0.017), without a significant change in the donor frequencies against third party (P=0.96). In eight further donor-recipient pairs, immunotoxin-depleted donor versus patient PBMNC HTLPf 4.5-fold (mean 1/155,000 before and 1/839,000 after depletion, P=0.007). There was a smaller non-significant 1.8-fold reduction in donor-versus-leukaemia HTLPf from 1/192,000 to 1/334,000 (P=0.19). These results suggest that selective T-cell depletion can significantly deplete donor anti-host reactivity while conserving anti-leukaemia reactivity in HLA-matched donor-recipient pairs.

Bone Marrow Transplantation↗

PubMed1998

Haematological response of patients with myelodysplastic syndrome to antithymocyte globulin is associated with a loss of lymphocyte-mediated inhibition of CFU-GM and alterations in T-cell receptor Vbeta profiles.

We have demonstrated that 44% of myelodysplastic syndrome (MDS) patients with cytopenia have a haematological response to antithymocyte globulin (ATG). Three ATG responders and two non-responders with refractory anaemia were further studied for lymphocyte-mediated inhibition of bone marrow using a standard CFU-GM assay. In responders, peripheral blood lymphocytes (PBL) added at a 5:1 ratio suppressed CFU-GM by 54+/-9% (P=0.04) and was reversed by ATG treatment. Pre-treatment marrow depleted of CD3 lymphocytes, increased CFU-GM by 32% (P=0.02) in an ATG responder, but not in a non-responder. CD3 lymphocytes from 6-month post-treatment marrow did not inhibit pre-treatment CFU-GM, indicating ATG had affected the T cells. Pre-treatment marrow depleted of CD8 lymphocytes, increased CFU-GM by 60% (P=0.01) and 49% (P=0.03) in two ATG responders, but not in a non-responder. Inhibition required cell-cell interaction through MHCI. TCRVbeta families, analysed by SSCP, changed from clonal to polyclonal in one ATG responder after 6 months, but clones persisted in a non-responder. These results indicate patients with refractory anaemia who respond to ATG have CD8 T-cell clones that mediate MHCI-restricted suppression of CFU-GM which are replaced by polyclonal T cells that do not suppress CFU-GM after ATG treatment.

Adult↗

PubMed1997

Regulation of a graft-versus-leukemia effect by major histocompatibility complex class II molecules on leukemia cells: HLA-DR1 expression renders K562 cell tumors resistant to adoptively transferred lymphocytes in severe combined immunodeficiency mice/nonobese diabetic mice.

To understand the role of key molecules in determining the strength and nature of allogeneic T-cell response to leukemia, we transfected HLA-DR1 into the major histocompatibility complex (MHC)-deficient, natural killer (NK)-cell sensitive K562 leukemia cell line. Untransfected K562 cells stimulated NK proliferation in vitro and formed subcutaneous tumors in severe combined immunodeficiency/non-obese diabetic (SCID/NOD) mice. Tumor growth was inhibited by adoptive intravenous transfer of fresh unprimed peripheral blood mononuclear cells (PBMC). In contrast, HLA-DR1 transfected cells stimulated CD4(+) T cells, but not NK-cell proliferation in vitro and formed tumors resistant to fresh PBMC in SCID/NOD mice. Tumors not expressing MHC were infiltrated with CD16(+)CD56(+) lymphocytes whereas nonregressing HLA-DR1 expressing tumors showed only a scanty infiltration with both T-cell and NK-cell subsets. The results indicate that MHC class II expression by leukemia cells can determine the effector cell type that it engages. In vivo MHC class II expression rendered K562 cell tumors resistant to NK-cell mediated antitumor reactivity.

Adoptive Transfer↗

PubMed1997

Cytotoxic T lymphocytes specific for a nonpolymorphic proteinase 3 peptide preferentially inhibit chronic myeloid leukemia colony-forming units.

We previously showed that a peptide (PR1) derived from the primary granule enzyme proteinase 3 induced peptide specific cytotoxic T lymphocytes (CTL) in a normal HLA-A2.1+ individual. These CTL showed HLA-restricted cytotoxicity to myeloid leukemias (which overexpress proteinase 3). To further investigate their antileukemic potential, we studied the ability of PR1-specific CTL, derived from two HLA-A2.1+ normal individuals, to inhibit colony-forming unit granulocyte-macrophage (CFU-GM) from normal and leukemic individuals. CTL from 20 day PR1 peptide-pulsed lymphocyte cultures showed 89% to 98% HLA-A2.1-restricted colony inhibition of chronic myeloid leukemia targets. Colony formation in normal HLA-A2.1+ bone marrow or HLA-A2.1- CML cells was not inhibited. Sequencing of the exon encoding PR1 showed that colony inhibition was not caused by polymorphic differences in proteinase 3 between effectors and targets. Analysis by flow cytometry showed that proteinase 3 was overexpressed in the leukemia targets compared with normal marrow targets (median channel fluorescence 1,399 v 298, P = .009). These results show that PR1-specific allogeneic T cells preferentially inhibit leukemic CFU-GM based on overexpression of proteinase 3, and that proteinase 3-specific CTL could be used for leukemia-specific adoptive immunotherapy.

Bone Marrow↗

PubMed1997

Association of natural killer cell immune recovery with a graft-versus-leukemia effect independent of graft-versus-host disease following allogeneic bone marrow transplantation.

There is good evidence that T lymphocytes play an important role in the graft-versus-leukemia (GVL) effect following allogeneic bone marrow transplantation (BMT) for hematologic malignancies. However, the role of natural killer (NK) cells in GVL is less clear. To further investigate a possible association of NK cells with GVL we studied 15 patients undergoing BMT for chronic myeloid leukemia (CML), correlating T-cell (CD4+ and CD8+) and NK-cell (CD16+ 56+) recovery with relapse and graft-versus-host disease (GVHD). Patients were studied on three occasions up to 9 months after BMT, for lymphocyte surface phenotype and for spontaneous and IL-2-stimulated (LAK cell) cytotoxic function. Circulating CD8+ and NK but not CD4+ cell numbers were significantly lower in five patients who relapsed compared with those remaining in remission after BMT (mean 0.03 vs 0.32 x 10(9)/l, p = 0.002 for CD8+ cells: mean 0.03 vs 0.11 x 10(9)/l, p = 0.002 for NK cells). There was no correlation of CD4+. CD8+, or NK cell numbers and development of grade-II or more acute GVHD. Spontaneous NK cytotoxic function rose to within the normal range in the first month after BMT. LAK function remained low during the study period. These results link NK cell recovery more closely with a GVL than with a GVH effect.

Adolescent↗

PubMed1997

Preferential usage of T cell receptor (TCR) V beta by allogeneic T cells recognizing myeloid leukemia cells: implications for separating graft-versus-leukemia effect from graft-versus-host disease.

New understanding of the alloresponse following bone marrow transplantation supports the possibility that the graft-versus-host disease (GVHD) response can be separated from a favorable graft-versus-leukemia (GVL) effect. We used chronic myeloid leukemia (CML) cells to generate 122 recipient-reactive T cell clones from a closely HLA-matched sibling responder. Clones were tested for their proliferative response to stimulator CML cells or PHA-transformed (non-leukemic) lymphoblasts. Of 78 clones tested, 32 recognized both leukemia cells and PHA blasts, 19 only CML and four only PHA blasts. The remainder were non-specific responders. This functional specificity corresponded to distinct patterns of T cell receptor (TCR) V beta usage: clones recognizing CML cells preferentially used V beta 5, V beta 6/7 while clones recognizing both CML and PHA blasts or only PHA blasts preferentially used V beta 3 and V beta 8. It may therefore be possible to identify in vitro-generated myeloid leukemia-restricted donor T cells by their pattern of V beta usage. TCR V beta antibodies could thus be used to select and expand leukemia-restricted donor T cells for transfusion after BMT to specifically enhance the GVL response.

Bone Marrow Transplantation↗

PubMed1997

Immune escape from a graft-versus-leukemia effect may play a role in the relapse of myeloid leukemias following allogeneic bone marrow transplantation.

We studied patients relapsing with myeloid leukemias following allogeneic bone marrow transplantation (BMT) for evidence of immune escape by clonal evolution of the leukemia. Relapsed cells from four out of five patients had a reduced ability to stimulate proliferation of lymphocytes from an HLA-mismatched responder. There was decreased susceptibility to lysis by CTL in three and reduced susceptibility to NK-mediated lysis in one. Relapsed leukemias had marked alterations in expression of critical surface molecules involved in immune responsiveness. Three had decreased expression of MHC class I and II, with no change or increase in CD54 (ICAM-1) or CD80 (B7.1). None of these responded to treatment with donor lymphocytes. Three patients showed no change, or increased expression of MHC with no change or decrease in ICAM-1 or B7.1. Two achieved remission - one in response to donor lymphocytes and one following withdrawal of cyclosporine. In one patient transplanted with myelodysplastic syndrome in transformation, interferon-gamma upregulated expression of MHC molecules in relapsed cells and increased their stimulatory capacity and target susceptibility to unmatched responder lymphocytes. These results suggest that immune escape through clonal evolution of the leukemia is a common occurrence in patients who relapse with myelogenous leukemias after BMT.

Adolescent↗

PubMed1997

The allogeneic CD4+ T-cell-mediated graft-versus-leukemia effect.

CD4+ T-cells have emerged as important cells in the initiation and delivery of the GVL response. Nevertheless it seems likely that they act in concert with other T-cells and NK cell effectors to produce the full in vivo effect of GVL. How they interact with other effectors is yet to be determined. Furthermore it is very likely that different hematological malignancies have different susceptibility to attack by various lymphocyte subsets, depending upon their MHC expression, nature of the antigens presented and other properties not yet defined. Here we specifically focus on the role of CD4+ T-cells in mediating GVL, particularly in chronic myeloid leukemia. Candidate antigens recognised by CD4+ cells are described and new approaches to GVL modulation in clinical bone marrow transplantation are discussed.

Bone Marrow Transplantation↗

PubMed1996

Targeted T-cell therapy for human leukemia: cytotoxic T lymphocytes specific for a peptide derived from proteinase 3 preferentially lyse human myeloid leukemia cells.

Proteinase 3 is present in high concentration in the primary granules of acute and chronic myeloid leukemia blasts, and may represent a potential T-cell target antigen. We screened proteinase 3 against the binding motif of HLA-A2.1. Based on its high predicted binding, a 9-mer peptide, "PR-1," was synthesized and tested for binding to HLA-A2.1 using the T2 cell line. PR-1 at 100 micrograms/mL significantly increased expression of HLA-A2.1, with median channel of fluorescence increasing from 22 to 294. Binding half-life was determined to be 1,460 minutes by I125-labeled beta 2-microglobulin incorporation. HLA-A2.1+ peripheral blood mononuclear cells from a normal donor were used to generate a T-cell line specific for PR-1. The line demonstrated 85% PR-1-specific lysis at an E:T ratio of 50:1, compared with 20% lysis without PR-1, using T2 cells as targets. It also showed 79% specific lysis to fresh chronic myelogenous leukemia blasts, 54% to fresh acute myelogenous leukemia blasts, and only background lysis (< 20%) to HLA-A2.1+ normal allogeneic marrow cells. The amount of lysis of HLA-A2.1+ myeloid cells was proportional to cytoplasmic proteinase 3 expression. Thus, HLA-A2.1-restricted cytotoxic T cells, raised against a peptide contained in proteinase 3, preferentially lysed fresh human leukemic cells.

Amino Acid Sequence↗

PubMed1996

Alloreactive CD4+ T lymphocytes can exert cytotoxicity to chronic myeloid leukaemia cells processing and presenting exogenous antigen.

Existing evidence supports that CD4+ T lymphocytes play a role in the graft-versus-leukaemia (GVL) reaction after allogeneic bone marrow transplantation (BMT) for chronic myeloid leukaemia (CML), not only as initiators of the immune response but also as effectors of GVL. In BMT between HLA-identical pairs this CD4-mediated GVL would require CML cells to process and present antigens through MHC class II molecules. To investigate whether CML cells are capable of processing and presenting antigens, and suitable targets for CD4+ T-cell-mediated cytotoxicity, we generated HLA-DR1-restricted CD4+ cytotoxic T-cell clones that specifically recognized tuberculous purified protein derivative (PPD). We have shown that CML cells and B lymphoblastoid cell line (B-LCL) cells but not PHA-blasts from patients with CML processed exogenous antigen, PPD, and induced proliferative and cytotoxic CD4+ T-cell responses. Antigen presentation was blocked by antibodies to HLA-DR but not to MHC class I and by treatment with chloroquine and brefeldin. This indicates that CML cells use a classic MHC class II antigen processing pathway to present PPD antigens to CD4+ T cells. Cytotoxicity to CML was shown by antibody blocking studies to be mediated mainly through fas antigen. These findings indicate that donor CD4+ T cells alone are sufficient to mediate GVL effects following allogeneic BMT for CML.

Bone Marrow Transplantation↗

PubMed1996

Interaction of natural killer cells with MHC class II: reversal of HLA-DR1-mediated protection of K562 transfectant from natural killer cell-mediated cytolysis by brefeldin-A.

Major histocompatibility complex (MHC) class I antigens on tumour cell surfaces have been shown to modulate target susceptibility to natural killer (NK) cell-mediated lysis in some, although not all, systems investigated. MHC class II expression may also affect NK cell function, but the mechanism by which MHC class II antigen regulates NK cell activity has not been fully examined. In this study we induced HLA-DR1 expression by gene transfection into the classic NK-sensitive K562 cell line to study the interaction of NK cells with MHC class II molecules and the effect of brefeldin-A (BFA), an endogenous antigen-processing pathway blocker, on NK-target cell interaction. We demonstrated that the expression of HLA-DR1 on the cell surface reduced K562 cell susceptibility to NK lysis by peripheral blood monuclear cells and a NK cell line. The effect was demonstrable in prolonged (8 hr) cytotoxicity assays and was blocked by pretreatment of target cells with anti-HLA-DR antibody. Treatment of K562 DR transfectant with BFA abrogated the resistance of K562 transfectant to NK-mediated cytolysis. These findings indicate that HLA class II molecules regulate NK cell function and target recognition, and suggest that endogenous peptides presented through MHC molecules are responsible for regulating NK cytolysis.

Brefeldin A↗

PubMed1996

Specific depletion of alloreactivity against haplotype mismatched related individuals by a recombinant immunotoxin: a new approach to graft-versus-host disease prophylaxis in haploidentical bone marrow transplantation.

Haploidentical bone marrow transplantation (BMT) is associated with a high risk of severe graft-versus-host disease (GVHD). While pan-T cell depletion of the graft is the most effective means of preventing severe GVHD, it is associated with delayed recovery of T cell function leading to fatal infections. We used two related Pseudomonas exotoxin-based immunotoxins, anti-Tac(Fv)-PE38 and anti-Tac(Fv)-PE38KDEL, that both target the IL-2 receptor on activated T cells, to specifically deplete alloreactive lymphocytes against haploidentical stimulators. The functional capacity of the remaining lymphocytes was tested in proliferative assays against the original haploidentical stimulator and pooled cells from other mismatched donors (third party). We varied the recombinant toxin concentration and schedule to determine the optimum conditions for selective depletion. In 10 experiments, the mean residual reactivity after depletion was 7.6 +/- 1.4% against the haploidentical stimulator and 64.2 +/- 5% against the third party, expressed as a percentage of the undepleted response to the same stimulators. Depletion was shown to be specific for mixed lymphocyte culture (MLC)-activated lymphocytes. The immunotoxin did not affect CFU-GM growth of normal BM cells. This selective depletion of haploidentical alloreactivity could be used to prevent GVHD while conserving immune recovery following haploidentical BMT.

ADP Ribose Transferases↗

PubMed1995

Cellular and cytokine-mediated effects of CD4-positive lymphocyte lines generated in vitro against chronic myelogenous leukemia.

Leukemia cells from a patient with chronic myelogenous leukemia (CML) in accelerated phase were used to generate CD4+, CD8- T lymphocyte lines from an unrelated normal subject sharing HLA-A2 and DR4 with the patient. In chromium release cytotoxicity assays, lines showed specificity for patient cells and were unreactive against third-party CML and K562 cells. Cytotoxicity was blocked by anti HLA-DR on target cells. Some lines showed preferential cytotoxicity to PHA-induced lymphoblasts and some to CML cells. There was a broad correlation between cytotoxicity to CML cells by 51Cr release and CFU-CM inhibition. However, even weakly cytotoxic lines were inhibitory to CML CFU-GM. This effect was partly mediated by the T cell line supernatant: four of five supernatants tested inhibited the growth of CFU-GM. Antibody neutralization studies demonstrated the presence of gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in these supernatants. There was a greater suppression of CML CFU-GM when compared with CFU-GM from normal individuals. One supernatant from a noncytotoxic T cell line stimulated CFU-GM and was demonstrated by antibody neutralization studies to contain interleukin-3 (IL-3) and GM-CSF. These data indicate that alloreacting CD4 cells exert both cytotoxic and cytokine-mediated antileukemia effects which may relate to the graft-vs.-leukemia (GVL) effect in CML following bone marrow transplantation.

Antibodies, Monoclonal↗

PubMed1994

Comparison of helper and cytotoxic antirecipient T cell frequencies in unrelated bone marrow transplantation.

Donor/recipient histocompatibility antigen differences initiate acute graft-versus-host disease (GVHD) after bone marrow transplantation. Frequency analysis, using limiting dilution techniques, of functionally defined (helper or cytotoxic) antirecipient T lymphocyte precursors in the peripheral blood of the donor has been shown to be an accurate predictor for the development of moderate-to-severe acute GVHD. Here, we describe a sensitive assay for measuring alloreactive helper (IL-2-producing) T lymphocyte precursor (HTLp) frequencies, and compare the ability of this assay and the cytotoxic T lymphocyte precursor (CTLp) assay to detect HLA- class II and class I differences and to predict clinical outcome in a cohort of unrelated donor/recipient BMT pairs. Twenty-two pairs underwent unrelated donor BMT. Patients with high (> 1:100 x 10(3)) HTLp or CTLp frequencies had a higher incidence of moderate-to-severe (grades II-IV) acute GVHD (80% and 100%, respectively) than pairs with low (< 1:100 x 10(3)) frequencies (40% and 57%, respectively). Ten (45%) patients have died, but all patients with both a low HTLp and low CTLp frequency remain alive. The HTLp and CTLp assays provided similar predictive information for outcome. Given that the HTLp assay is more rapid and less labor intensive, it offers an additional or alternative functional method for donor selection in unrelated donor BMT.

Bone Marrow Transplantation↗