Contemp Clin Trials
July 2024
Background: Allogeneic stem cell transplantation (allo-SCT) is the preferred therapy for patients with high-risk or relapsed hematologic malignancies, but may be complicated by psychological distress (e.g., depression, anxiety) and symptom burden (e.
View Article and Find Full Text PDFBackground: VEGF promotes an immunosuppressive microenvironment and contributes to immune checkpoint inhibitor resistance in cancer. We aimed to assess the activity of the VEGF receptor tyrosine-kinase inhibitor axitinib plus the anti-PD-1 immune checkpoint inhibitor pembrolizumab in patients with sarcoma.
Methods: This single-centre, single-arm, phase 2 trial was undertaken at a tertiary care academic medical centre in Miami, FL, USA, and participants were recruited from all over the USA and internationally.
Cytomegalovirus (CMV) is the most common viral infection in hematopoietic cell transplantation (HCT) recipients. We performed deep phenotyping of CMV-specific T cells to predict CMV outcomes following allogeneic HCT. By using 13-color flow cytometry, we studied ex vivo CD8 T-cell cytokine production in response to CMV-pp65 peptides in 3 clinically distinct subgroups of CMV-seropositive HCT patients: (1) (n = 19): did not have evidence of CMV DNAemia on surveillance testing; (2) (n = 16): spontaneously resolved low-grade CMV DNAemia without antiviral therapy; and (3) (NC; n = 21): experienced clinically significant CMV.
View Article and Find Full Text PDFAllogeneic hematopoietic stem cell transplantation (SCT) offers the best chance for cure and/or long-term survival for a broad range of diseases, including many high-risk hematologic malignancies, bone marrow failure states and subsets of inherited metabolic diseases and hemoglobinopathies. Clinical advances in allogeneic SCT have resulted in dramatically improved clinical outcomes over the past two decades, resulting in a significant expansion of transplant utilization to many recipients who would previously have been excluded from consideration, including elderly recipients and individuals lacking matched sibling or unrelated donors. Despite these advances, significant clinical challenges remain, including delayed immune reconstitution and the frequent occurrence of acute and chronic graft-versus-host disease, especially in the unrelated donor transplant setting.
View Article and Find Full Text PDFImmunosuppressive strategies currently used in hematopoietic stem cell transplantation reliably decrease graft-versus-host disease (GVHD) rates, but also impair pathogen-specific immunity. Experimental transplant studies indicate that GVHD-initiating alloreactive T cells reside primarily in naive and central memory T-cell compartments. In contrast, virus-specific T cells comprise a more differentiated memory population.
View Article and Find Full Text PDFVitamin D deficiency is adversely associated with diseases characterized by inflammation. The combination of the high incidence of vitamin D deficiency in patients undergoing allogeneic stem cell transplants (SCT) and the potential role of vitamin D deficiency in influencing graft-versus-host disease led us to further characterize the expression of VDR on alloreactive T cells. We hypothesized that vitamin D receptor expression may directly regulate alloreactive T cell responses.
View Article and Find Full Text PDFCross-presentation is an important mechanism by which exogenous tumor antigens are presented to elicit immunity. Because neutrophil elastase (NE) and proteinase-3 (P3) expression is increased in myeloid leukemia, we investigated whether NE and P3 are cross-presented by dendritic cells (DC) and B cells, and whether the NE and P3 source determines immune outcomes. We show that NE and P3 are elevated in leukemia patient serum and that levels correlate with remission status.
View Article and Find Full Text PDFBackground Aims: Tumor antigen-specific cytotoxic T lymphocytes (CTL) have been used in the treatment of human cancer, including leukemia. Several studies have established PR1 peptide, an HLA-A2.1-restricted peptide derived from proteinase 3 (P3), as a human leukemia-associated antigen.
View Article and Find Full Text PDFLate memory T cell skewing is observed in the setting of immune recovery after cord blood transplantation, and may be associated with inferior control of viral reactivation and cancers. Therefore, we sought to understand how late memory cells differ functionally from earlier stage memory T cells, and whether surface phenotypes associated with differentiation stages were predictably associated with functional signatures. Higher order cytokine flow cytometry allows characterization of human T cells based on complex phenotypic markers and their differential capacity to simultaneously secrete effector proteins, including cytokines and chemokines.
View Article and Find Full Text PDFThe alpha(4)beta(1) integrin VLA-4 (very-late activation antigen-4) and the lineage-specific CD4 and CD8 receptors have been proposed as putative co-stimulatory receptors on T cells. To assess the relative contribution of signaling through the TCR, CD28 and these accessory molecules, we activated human T cells using soluble antibodies recognizing all four of these T-cell receptor classes (CD3, CD28, CD4/CD8, and VLA-4), and we assessed the degree of activation using higher-order flow cytometry detecting intracellular Erk1/2 phosphorylation and production of IL-2 and IFN-gamma. We found that: (1) co-stimulation via CD4/CD8, in addition to CD28, is required for optimal T-cell activation; (2) VLA-4 binding consistently potentiates CD4(+) and CD8(+) T-cell activation; (3) augmentation of T-cell activation through VLA-4 binding is most pronounced following engagement of CD4/CD8.
View Article and Find Full Text PDFTumor necrosis factor (TNF) receptor 1 (TNFR1, p55) and 2 (TNFR2, p75) are characterized by several cysteine-rich modules in the extracellular domain, raising the possibility that redox-induced modifications of these cysteine residues might alter TNFR function. To test this possibility, we examined fluorescence resonance energy transfer (FRET) in 293T cells transfected with CFP- and YFP-tagged TNFRs exposed to the thiol oxidant diamide. Treatment with high concentrations of diamide (1 mm) resulted in an increase in the FRET signal that was sensitive to inhibition with the reducing agent dithiothreitol, suggesting that oxidative stress resulted in TNFR self-association.
View Article and Find Full Text PDFBackground: Non-small cell lung cancer (NSCLC) is the most common cause of cancer-related death in Western countries. Developing more effective NSCLC therapeutics will require the elucidation of the genetic and biochemical bases for this disease. Bronchioalveolar stem cells (BASCs) are a putative cancer stem cell population in mouse models of oncogenic K-ras-induced lung adenocarcinoma, an histologic subtype of NSCLC.
View Article and Find Full Text PDFAdoptive therapy with antigen-specific T cells is a promising approach for the treatment of infectious diseases and cancer. However, cloning of antigen-specific T cells by the traditional approach of limiting dilution is a time-consuming, laborious, and inefficient process. Here, we describe a novel flow cytometric strategy for rapid isolation of human tumor antigen-specific T-cell clones by using T-cell receptor (TCR) Vbeta antibodies in combination with carboxyfluorescein succinimidyl ester (CFSE)-based proliferation assay.
View Article and Find Full Text PDFAdvances in immune assessment, including the development of T-cell receptor excision circle (TREC) assays of thymopoiesis, cytokine-flow cytometry assays of T-cell function, and higher-order phenotyping of T-cell maturation subsets have improved our understanding of T-cell homeostasis. Limited data exist using these methods to characterize immune recovery in adult cord blood (CB) transplant recipients, in whom infection is a leading cause of mortality. We now report the results of a single-center prospective study of T-cell immune recovery after cord blood transplantation (CBT) in a predominantly adult population.
View Article and Find Full Text PDFT cell activation and differentiation is accompanied and mediated by transcriptional reprogramming. The NFATc1 transcription factor is strongly induced upon T cell activation and controls numerous genes involved in the T cell effector function. However, its regulation by physiological stimuli in primary T cells has not been well understood.
View Article and Find Full Text PDFBy confining germline transcription as a byproduct of the mechanisms inherent to genetic rearrangements, the translation of respective mRNAs and their biological relevance might have been overlooked. Here we report the identification, cloning, and biochemical characterization of a human Vkappa-like protein that is encoded by a germline transcript. This surrogate protein assembles with the immunoglobulin mu heavy chain at the surface of B cell progenitors and precursors to form a kappa-like antigen receptor.
View Article and Find Full Text PDFHuman T-cell alloreactivity plays an important role in many disease processes, including the rejection of solid organ grafts and graft-versus-host disease (GVHD) following allogeneic stem cell transplantation. To develop a better understanding of the T cells involved in alloreactivity in humans, we developed a cytokine flow cytometry (CFC) assay that enabled us to characterize the phenotypic and functional characteristic of T cells responding to allogeneic stimuli. Using this approach, we determined that most T-cell alloreactivity resided within the CD4(+) T-cell subset, as assessed by activation marker expression and the production of effector cytokines (eg, tumor necrosis factor alpha [TNF]alpha) implicated in human GVHD.
View Article and Find Full Text PDFPoor immune reconstitution after haploidentical stem cell transplantation results in a high mortality from viral infections and relapse. One approach to overcome this problem is to selectively deplete the graft of alloreactive cells using an immunotoxin directed against the activation marker CD25. However, the degree of depletion of alloreactive cells is variable following stimulation with recipient peripheral blood mononuclear cells (PBMCs), and this can result in graft versus host disease (GVHD).
View Article and Find Full Text PDFThe small number of progenitor cells is the major limitation to the use of umbilical cord blood (UCB) for the transplantation of adults. We tested the hypothesis that two units transplanted simultaneously could each contribute to haematopoietic reconstitution. A patient with advanced acute lymphocytic leukaemia received a mismatched, unrelated UCB transplant using units from two donors after conditioning.
View Article and Find Full Text PDFEvidence suggests that T lymphocyte-mediated inhibition of hematopoiesis in myelodysplastic syndrome (MDS) contributes to cytopenia in some patients and can be reversed by treatment with immunosuppression. We examined the T-cell repertoires of 12 patients with MDS before and after antithymocyte globulin (ATG)-based treatment by T-cell receptor Vbeta (TCR-Vbeta) spectratype analysis. The average number of TCR-Vbeta families with skewed spectratypes, representative of clonal or oligoclonal T-cell populations, was 7.
View Article and Find Full Text PDFMolecular events involved in specification of early hematopoietic system are not well known. In Xenopus, a paired-box homeodomain family (Mix.1-4) has been implicated in this process.
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