CSF-1–dependant donor-derived macrophages mediate chronic graft-versus-host disease

Chronic GVHD (cGVHD) is the major cause of late, nonrelapse death following stem cell transplantation and characteristically develops in organs such as skin and lung. Here, we used multiple murine models of cGVHD to investigate the contribution of macrophage populations in the development of cGVHD. Using an established IL-17–dependent sclerodermatous cGVHD model, we confirmed that macrophages infiltrating the skin are derived from donor bone marrow (F4/80+CSF-1R+CD206+iNOS–). Cutaneous cGVHD developed in a CSF-1/CSF-1R–dependent manner, as treatment of recipients after transplantation with CSF-1 exacerbated macrophage infiltration and cutaneous pathology. Additionally, recipients of grafts from Csf1r–/– mice had substantially less macrophage infiltration and cutaneous pathology as compared with those receiving wild-type grafts. Neither CCL2/CCR2 nor GM-CSF/GM-CSFR signaling pathways were required for macrophage infiltration or development of cGVHD. In a different cGVHD model, in which bronchiolitis obliterans is a prominent manifestation, F4/80+ macrophage infiltration was similarly noted in the lungs of recipients after transplantation, and lung cGVHD was also IL-17 and CSF-1/CSF-1R dependent. Importantly, depletion of macrophages using an anti–CSF-1R mAb markedly reduced cutaneous and pulmonary cGVHD. Taken together, these data indicate that donor macrophages mediate the development of cGVHD and suggest that targeting CSF-1 signaling after transplantation may prevent and treat cGVHD

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Immune regulatory cell infusion for graft-versus-host disease prevention and therapy

Current approaches to prevent and treat graft-versushost disease (GVHD) after stem cell transplantation rely principally on pharmacological immune suppression. Such approaches are limited by drug toxicity, nonspecific immune suppression, and a requirement for long-term therapy. Our increased understanding of the regulatory cells and molecular pathways involved in limiting pathogenic immune responses opens the opportunity for the use of these cell subsets to prevent and/or GVHD. The theoretical advantages of this approach is permanency of effect, potential for facilitating tissue repair, and induction of tolerance that obviates a need for ongoing drug therapy. To date, a number of potential cell subsets have been identified, including FoxP3 regulatory T (Treg) and FoxP3IL-10 (FoxP3-negative) regulatory T (Tr1), natural killer (NK) and natural killer T (NKT) cells, innate lymphoid cells, and various myeloid suppressor populations of hematopoietic (eg, myeloid derived suppressor cells) and stromal origin (eg, mesenchymal stem cells). Despite initial technical challenges relating to large-scale selection and expansion, these regulatory lineages are now undergoing early phase clinical testing. To date, Treg therapies have shown promising results in preventing clinical GVHD when infused early after transplant. Results from ongoing studies over the next 5 yearswill delineate themost appropriate cell lineage, source (donor, host, third party), timing, and potential exogenous cytokine support needed to achieve the goal of clinical transplant tolerance

Neurogenesis in adult human

THIS report describes neurogenesis in the adult human olfactory epithelium in vitro. Olfactory epithelium was collected at autopsy and by biopsy, and grown in serum-free medium. Basic fibroblast growth factor induced the differentiation of bipolar cells which were immunopositive for several neuronal proteins but not glial proteins. [H-3]thymidine autoradiography confirmed that these neurones were born in vitro. The results demonstrate that the adult human olfactory epithelium retains the capacity for neurogenesis and neuronal differentiation, at least until the age of 72 years. It is now possible to examine neurones and neurogenesis in biopsies from patients with disorders that may involve a neurodevelopmental or neurodegenerative aetiology such as schizophrenia, bipolar disorder and Alzheimer's disease

PD-1 Dependent Exhaustion of CD8+ T Cells Drives Chronic Malaria

Malaria is a highly prevalent disease caused by infection by Plasmodium spp., which infect hepatocytes and erythrocytes. Blood-stage infections cause devastating symptoms and can persist for years. Antibodies and CD4+ T cells are thought to protect against blood-stage infections. However, there has been considerable difficulty in developing an efficacious malaria vaccine, highlighting our incomplete understanding of immunity against this disease. Here, we used an experimental rodent malaria model to show that PD-1 mediates up to a 95% reduction in numbers and functional capacity of parasite-specific CD8+ T cells. Furthermore, in contrast to widely held views, parasite-specific CD8+ T cells are required to control both acute and chronic blood-stage disease even when parasite-specific antibodies and CD4+ T cells are present. Our findings provide a molecular explanation for chronic malaria that will be relevant to future malaria-vaccine design and may need consideration when vaccine development for other infections is problematic

NKT cell–dependent leukemia eradication following stem cell mobilization with potent G-CSF analogs

NKT cells have pivotal roles in immune regulation and tumor immunosurveillance. We report that the G-CSF and FMS-like tyrosine kinase 3 ligand (Flt-3L) chimeric cytokine, progenipoietin-1, markedly expands the splenic and hepatic NKT cell population and enhances functional responses to α-galactosylceramide. In a murine model of allogeneic stem cell transplantation, donor NKT cells promoted host DC activation and enhanced perforin-restricted CD8(+) T cell cytotoxicity against host-type antigens. Following leukemic challenge, donor treatment with progenipoietin-1 significantly improved overall survival when compared with G-CSF or control, attributable to reduced graft-versus-host disease mortality and paradoxical augmentation of graft-versus-leukemia (GVL) effects. Enhanced cellular cytotoxicity was dependent on donor NKT cells, and leukemia clearance was profoundly impaired in recipients of NKT cell–deficient grafts. Enhanced cytotoxicity and GVL effects were not associated with Flt-3L signaling or effects on DCs but were reproduced by prolonged G-CSF receptor engagement with pegylated G-CSF. Thus, modified G-CSF signaling during stem cell mobilization augments NKT cell–dependent CD8(+) cytotoxicity, effectively separating graft-versus-host disease and GVL and greatly expanding the potential applicability of allogeneic stem cell transplantation for the therapy of malignant disease

Complement receptor C3aR1 controls neutrophil mobilization following spinal cord injury through physiological antagonism of CXCR2

Traumatic spinal cord injury (SCI) triggers an acute-phase response that leads to systemic inflammation and rapid mobilization of bone marrow (BM) neutrophils into the blood. These mobilized neutrophils then accumulate in visceral organs and the injured spinal cord where they cause inflammatory tissue damage. The receptor for complement activation product 3a, C3aR1, has been implicated in negatively regulating the BM neutrophil response to tissue injury. However, the mechanism via which C3aR1 controls BM neutrophil mobilization, and also its influence over SCI outcomes, are unknown. Here, we show that the C3a/C3aR1 axis exerts neuroprotection in SCI by acting as a physiological antagonist against neutrophil chemotactic signals. We show that C3aR1 engages phosphatase and tensin homolog (PTEN), a negative regulator of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway, to restrain C-X-C chemokine receptor type 2-driven BM neutrophil mobilization following trauma. These findings are of direct clinical significance as lower circulating neutrophil numbers at presentation were identified as a marker for improved recovery in human SCI. Our work thus identifies C3aR1 and its downstream intermediary, PTEN, as therapeutic targets to broadly inhibit neutrophil mobilization/recruitment following tissue injury and reduce inflammatory pathology

Chronic graft-versus-host disease after granulocyte colony-stimulating factor-mobilized allogeneic stem cell transplantation: The role of donor T-cell dose and differentiation

The use of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood as a source of stem cells has resulted in a high incidence of severe chronic graft-versus-host disease (cGVHD), which compromises the outcome of clinical allogeneic stem cell transplantation. We have studied the effect of G-CSF on both immune complex and fibrotic cGVHD directed to major (DBA/2 --> B6D2F1) or minor (B10.D2 --> BALB/c) histocompatibility antigens. In both models, donor pretreatment with G-CSF reduced cGVHD mortality in association with type 2 differentiation. However, after escalation of the donor T-cell dose, scleroderma occurred in 90% of the recipients of grafts from G-CSF-treated donors. In contrast, only 11% of the recipients of control grafts developed scleroderma, and the severity of hepatic cGVHD was also reduced. Mixing studies confirmed that in the presence of high donor T-cell doses, the severity of scleroderma was determined by the non-T-cell fraction of grafts from G-CSF-treated donors. These data confirm that the induction of cGVHD after donor treatment with G-CSF is dependent on the transfer of large numbers of donor T cells in conjunction with a putatively expanded myeloid lineage, providing a further rationale for the limitation of cell dose in allogeneic stem cell transplantation. (C) 2004 American Society for Blood and Marrow Transplantation