Interleukin-6 modulates graft-versus-host responses after experimental allogeneic bone marrow transplantation.

Purpose: The graft-versus-tumor (GVT) effect is a potent form of immunotherapy against many hematologic malignancies and some solid tumors. The beneficial GVT effect after allogeneic bone marrow transplantation (BMT) is tightly linked to its most significant complication, graft-versus-host disease (GVHD). The role of interleukin-6 (IL-6) after allogeneic BMT is not well understood.

A crucial role for host APCs in the induction of donor CD4+CD25+ regulatory T cell-mediated suppression of experimental graft-versus-host disease.

Allogeneic bone marrow transplantation is an effective treatment for a number of malignant and nonmalignant diseases (Applebaum. 2001. Nature.

Frequency of CD4(+)CD25(hi)FOXP3(+) regulatory T cells has diagnostic and prognostic value as a biomarker for acute graft-versus-host-disease.

The relationship between regulatory T cells (Tregs) and acute graft-versus-host disease (aGVHD) in clinical allogeneic bone marrow transplantation (BMT) recipients is not well established. We conducted a prospective analysis of peripheral blood Tregs as determined by the frequency of CD4(+)CD25(hi)FOXP3(+) lymphocytes in 215 BMT patients. Autologous BMT patients (N = 90) and allogeneic BMT patients without GVHD (N = 65) had similar Treg frequencies, whereas allogeneic patients with GVHD (N = 60) had Treg frequencies that were 40% less than those without GVHD.

Immunization with host-type CD8{alpha}+ dendritic cells reduces experimental acute GVHD in an IL-10-dependent manner.

Little is known about the role of active immunization in suppressing undesirable immune responses. Because CD8alpha(+) dendritic cells (DCs) suppress certain immune responses, we tested the hypothesis that immunization of donors with host-derived CD8alpha(+) DCs will reduce host-specific donor T-cell responses. BALB/c T cells from the animals that were immunized with B6 CD8alpha(+) DCs demonstrated, in vitro and in vivo, significantly reduced proliferation and secretion of inflammatory cytokines but showed enhanced secretion of interleukin-10 (IL-10).

Mesenchymal stem cells for treatment and prevention of graft-versus-host disease after allogeneic hematopoietic cell transplantation.

Allogeneic hematopoietic cell transplantation (allo-HCT) is an effective therapy for hematological malignancies and inherited diseases. However, acute graft-versus-host-disease (aGVHD) is a major life-threatening complication after allo-HCT and there are few therapeutic options for severe steroid-refractory aGVHD. Preliminary studies on co-transplantation of mesenchymal stem cells (MSCs) have shown an improvement in or resolution of severe aGVHD.

Extracorporeal photopheresis reverses experimental graft-versus-host disease through regulatory T cells.

Extracorporeal photopheresis (ECP), a technique that exposes isolated white blood cells to photoactivatable 8-methoxypsoralen and ultraviolet A radiation, is used clinically to treat cutaneous T-cell lymphoma and immune-mediated diseases such as graft-versus-host disease (GVHD). ECP is thought to control these diseases in part through direct induction of lymphocyte apoptosis, but its effects on the immune system beyond apoptosis remain poorly characterized. We have developed a novel method for incorporating ECP treatment into well-established and clinically relevant murine models of GVHD to examine its effects during an ongoing immune response.

Combined Th2 cytokine deficiency in donor T cells aggravates experimental acute graft-vs-host disease.

The role of T helper (Th) 1 and Th2 polarization in acute graft-vs-host-disease (GVHD) is unclear. We investigated the role of Th2 cytokine secretion by utilizing donor T cells that cannot make interleukin (IL)-4, IL-5, IL-9, and IL-13 from quadruple cytokine-deficient (Quad-KO) animals in a well-characterized BALB/c-->C57BL/6 model of allogeneic bone marrow transplantation. B6 recipients of BALB/c Quad-KO T cells demonstrated greater clinical severity, target organ damage, and mortality from GVHD than recipients of BALB/c wild-type (WT) T cells.

Critical role of host gammadelta T cells in experimental acute graft-versus-host disease.

Gammadelta T cells localize to target tissues of graft-versus-host disease (GVHD) and therefore we investigated the role of host gammadelta T cells in the pathogenesis of acute GVHD in several well-characterized allogeneic bone marrow transplantation (BMT) models. Depletion of host gammadelta T cells in wild-type (wt) B6 recipients by administration of anti-T-cell receptor (TCR) gammadelta monoclonal antibody reduced GVHD, and gammadelta T-cell-deficient (gammadelta-/-) BM transplant recipients experienced markedly improved survival compared with normal controls (63% vs 10%, P < .001).

Immunologic response to cryoablation of breast cancer.

Purpose: With improvements in breast imaging and image-guided interventions, there is interest in ablative techniques for breast cancer. Cryosurgery initiates inflammation and leaves tumor-specific antigens intact, which may induce an anti-tumor immune response. To help define the mechanisms involved in the cryoimmunologic response, we compared cryosurgery to surgery in a murine model of breast cancer.

Repifermin (keratinocyte growth factor-2) reduces the severity of graft-versus-host disease while preserving a graft-versus-leukemia effect.

Graft-versus-host disease (GVHD) is the principal complication after allogeneic bone marrow transplantation (BMT). Reductions in systemic GVHD are frequently associated with a corresponding diminishment of the graft-versus-leukemia (GVL) response. In this study, we tested the effects of a novel recombinant human keratinocyte growth factor, repifermin (keratinocyte growth factor-2), on the induction of GVHD in a well-defined murine BMT model (B6 --> B6D2F1).

Flt3 ligand therapy for recipients of allogeneic bone marrow transplants expands host CD8 alpha(+) dendritic cells and reduces experimental acute graft-versus-host disease.

Recent evidence suggests that dendritic cells (DCs) can regulate and amplify immune responses. Flt3 ligand (FL)-derived DC function was tested as a stimulator of allogeneic lymphocytes in vitro and in vivo. Treatment of mice with FL dramatically expanded DC number, but DCs isolated from FL-treated mice (FL DCs) were poor stimulators of allogeneic T-cell responses in vitro.

Donor leukocyte infusion from immunized donors increases tumor vaccine efficacy after allogeneic bone marrow transplantation.

Donor T cells play a critical role in mediating both harmful graft-versus-host disease (GVHD) and beneficial graft-versus-tumor effect after allogeneic bone marrow transplantation (BMT). We have recently demonstrated a novel treatment strategy to stimulate specific antitumor activity with preservation of tolerance to host antigens after T cell-depleted allogeneic BMT by vaccination of recipients with irradiated B16 melanoma cells engineered to secrete granulocyte-macrophage colony-stimulating factor. In this murine system, donor leukocyte infusion from a donor immunized with the recipient-derived B16 vaccines enhanced clinical activity of tumor vaccines without exacerbating GVHD.