Good Manufacturing Practice-compliant change of raw material in the manufacturing process of a clinically used advanced therapy medicinal product-a comparability study.

The development of medicinal products often continues throughout the different phases of a clinical study and may require challenging changes in raw and starting materials at later stages. Comparability between the product properties pre- and post-change thus needs to be ensured. Here, we describe and validate the regulatory compliant change of a raw material using the example of a nasal chondrocyte tissue-engineered cartilage (N-TEC) product, initially developed for treatment of confined knee cartilage lesions.

Increase of endothelial progenitor cells in acute graft-versus-host disease after allogeneic haematopoietic stem cell transplantation for acute myeloid leukaemia.

Introduction: Circulating endothelial progenitor cells (EPCs; CD31+ CD34(bright)CD133+ CD45(dim) cells) are novel markers of endothelial dysfunction and related to inflammatory processes such as acute graft-versus-host disease (aGvHD).

Patients And Methods: 47 patients with acute myeloid leukaemia (AML) who were in complete remission as they underwent allogeneic hematopoietic stem cell transplantation with myeloablative conditioning with PBSC as stem cell source were enrolled in the study. Blood samples for the quantitative analysis of circulating EPC levels were drawn at different time points in patients with and without aGvHD.

A novel, bedside technique to rapidly identify umbilical cord blood units with high total nucleated cell numbers.

Background: With increasing demand for umbilical cord blood units (CBUs) with total nucleated cell (TNC) counts of more than 150 × 10(7) , preshipping assessment is mandatory. Umbilical cord blood processing requires aseptic techniques and laboratories with specific air quality and cleanliness. Our aim was to establish a fast and efficient method for determining TNC counts at the obstetric ward without exposing the CBU to the environment.

Cell Growth Dynamics in Embryonic and Adult Mouse Thyroid Revealed by a Novel Approach to Detect Thyroid Gland Subpopulations.

Background: The thyroid is composed of endocrine epithelial cells, blood vessels, and mesenchyme. However, no data exist thus far on absolute cell numbers, relative distribution, and proliferation of the different cell populations in the developing and mature thyroid. The aim of this study was therefore to establish a flow cytometry protocol that allows detection and quantification of discrete cell populations in embryonic and adult murine thyroid tissues.

Impaired thymic expression of tissue-restricted antigens licenses the de novo generation of autoreactive CD4+ T cells in acute GVHD.

During acute graft-versus-host disease (aGVHD) in mice, autoreactive T cells can be generated de novo in the host thymus implying an impairment in self-tolerance induction. As a possible mechanism, we have previously reported that mature medullary thymic epithelial cells (mTEC(high)) expressing the autoimmune regulator are targets of donor T-cell alloimmunity during aGVHD. A decline in mTEC(high) cell pool size, which purges individual tissue-restricted peripheral self-antigens (TRA) from the total thymic ectopic TRA repertoire, weakens the platform for central tolerance induction.

Epithelial cytoprotection sustains ectopic expression of tissue-restricted antigens in the thymus during murine acute GVHD.

Development of acute graft-versus-host disease (aGVHD) predisposes to chronic GVHD with autoimmune manifestations. A characteristic of experimental aGVHD is the de novo generation of autoreactive T cells. Central tolerance is dependent on the intrathymic expression of tissue-restricted peripheral self-antigens (TRA), which is in mature medullary thymic epithelial cells (mTEC(high)) partly controlled by the autoimmune regulator (Aire).

Use of human embryonic stem cells and umbilical cord blood stem cells for research and therapy: a prospective survey among health care professionals and patients in Switzerland.

Background: Scientific progress in the biology of hematopoietic stem cells (HSCs) provides opportunities for advances in therapy for different diseases. While stem cell sources such as umbilical cord blood (UCB) are unproblematic, other sources such as human embryonic stem cells (hESCs) raise ethical concerns.

Study Design And Methods: In a prospective survey we established the ethical acceptability of collection, research, and therapy with UCB HSCs versus hESCs among health care professionals, pregnant women, patients undergoing in vitro fertilization therapy, parents, and HSC donors and recipients in Switzerland.

High acceptance rate of hybrid allogeneic-autologous umbilical cord blood banking among actual and potential Swiss donors.

Background: Two competitive concepts of umbilical cord blood (UCB) banking are currently available: either allogeneic UCB is donated to a public bank or autologous cells are stored in a private bank. Allogeneic-autologous hybrid banking is a new concept that combines these two approaches. However, acceptance of hybrid UCB banking among potential donors is unknown to date.

Thymic T-cell development in allogeneic stem cell transplantation.

Cytoreductive conditioning regimens used in the context of allogeneic hematopoietic cell transplantation (HCT) elicit deficits in innate and adaptive immunity, which predispose patients to infections. As such, transplantation outcomes depend vitally on the successful reconstruction of immune competence. Restoration of a normal peripheral T-cell pool after HCT is a slow process that requires the de novo production of naive T cells in a functionally competent thymus.

The role of the thymus in allogeneic hematopoietic stem cell transplantation.

Allogeneic haematopoietic stem cell transplantation (HSCT) is used to treat an increasing number of congenital and acquired disorders of the haematopoietic system. Even though cytoreductive conditioning regimens vary in intensity, all clinically used protocols invariably cause side effects that compromise transiently or long-term the response of the natural and the adaptive immune systems. However, in the context of the reconstruction of immunity, the generation of naïve T cells constitutes a slow process, and requires a functionally competent thymus.

Emerging strategies to boost thymic function.

The thymus constitutes the primary lymphoid organ for the generation of T cells. Its function is particularly susceptible to various negative influences ranging from age-related involution to atrophy as a consequence of malnutrition, infection or harmful iatrogenic influences such as chemotherapy and radiation. The loss of regular thymus function significantly increases the risk for infections and cancer because of a restricted capacity for immune surveillance.

Stabilized beta-catenin in thymic epithelial cells blocks thymus development and function.

Thymic T cell development is dependent on a specialized epithelial microenvironment mainly composed of cortical and medullary thymic epithelial cells (TECs). The molecular programs governing the differentiation and maintenance of TECs remain largely unknown. Wnt signaling is central to the development and maintenance of several organ systems but a specific role of this pathway for thymus organogenesis has not yet been ascertained.

The immunopathology of thymic GVHD.

The clinical success of allogeneic hematopoietic stem cell transplantation (HSCT) depends on the appropriate reconstitution of the host's immune system. While recovery of T-cell immunity may occur in transplant recipients via both thymus-dependent and thymus-independent pathways, the regeneration of a population of phenotypically naive T cells with a broad receptor repertoire relies entirely on the de novo generation of T-cells in the thymus. Preclinical models and clinical studies of allogeneic HSCT have identified the thymus as a target of graft-versus-host disease (GVHD), thus limiting T-cell regeneration.

The thymus in GVHD pathophysiology.

A favorable outcome of allogeneic hematopoietic stem-cell transplantation (HSCT) depends on the complete reconstitution of the host's immune system. While recovery of peripheral T cells occurs in transplant recipients via both thymus-dependent and thymus-independent pathways, the regeneration of a population of phenotypically naive T cells with a broad T-cell receptor (TCR) repertoire relies entirely on the de novo generation of T cells in the thymus. However, preclinical models and clinical studies of allogeneic HSCT have identified the thymus as a target of graft-versus-host disease (GVHD).

A short primer on early molecular and cellular events in thymus organogenesis and replacement.

Haematopoietic precursors have to undergo a complex series of maturational steps in the thymus before they exit into the periphery as functional T lymphocytes. Thymic stroma cells, the majority being of epithelial origin, provide the functional partners for the maturational progression along this differentiation pathway. Here we review some of the molecular and cellular mechanisms that account for thymus organogenesis and discuss a strategy to use thymic epithelial precursor cells for the regeneration of the thymic microenvironment.

Normal erythropoiesis but severe polyposis and bleeding anemia in Smad4-deficient mice.

The tumor suppressor Smad4 mediates signaling by the transforming growth factor beta (TGF-beta) superfamily of ligands. Previous studies showed that several TGF-beta family members exert important functions in hematopoiesis. Here, we studied the role of Smad4 in adult murine hematopoiesis using the inducible Mx-Cre/loxP system.

Donor T-cell alloreactivity against host thymic epithelium limits T-cell development after bone marrow transplantation.

Acute graft-versus-host disease (aGVHD) impairs thymus-dependent T-cell regeneration in recipients of allogeneic bone marrow transplants through yet to be defined mechanisms. Here, we demonstrate in mice that MHC-mismatched donor T cells home into the thymus of unconditioned recipients. There, activated donor T cells secrete IFN-gamma, which in turn stimulates the programmed cell death of thymic epithelial cells (TECs).

Keratinocyte growth factor (KGF) enhances postnatal T-cell development via enhancements in proliferation and function of thymic epithelial cells.

The systemic administration of keratinocyte growth factor (KGF) enhances T-cell lymphopoiesis in normal mice and mice that received a bone marrow transplant. KGF exerts protection to thymic stromal cells from cytoablative conditioning and graft-versus-host disease-induced injury. However, little is known regarding KGF's molecular and cellular mechanisms of action on thymic stromal cells.

A short primer on early molecular and cellular events in thymus organogenesis and replacement.

Haematopoietic precursors have to undergo a complex series of maturational steps in the thymus before they exit into the periphery as functional T lymphocytes. Thymic stroma cells, the majority being of epithelial origin, provide the functional partners for the maturational progression along this differentiation pathway. Here we review some of the molecular and cellular mechanisms that account for thymus organogenesis and discuss a strategy to use thymic epithelial precursor cells for the regeneration of the thymic microenvironment.

Invasion of hematopoietic cells into the brain of amyloid precursor protein transgenic mice.

The significance of the peripheral immune system in Alzheimer's disease pathogenesis remains controversial. To study the CNS invasion of hematopoietic cells in the course of cerebral amyloidosis, we used a green fluorescence protein (GFP)-bone marrow chimeric amyloid precursor protein transgenic mouse model (APP23 mice). No difference in the number of GFP-positive invading cells was observed between young APP23 mice and nontransgenic control mice.

Leydig cell injury as a consequence of an acute graft-versus-host reaction.

Hematopoietic stem cell transplantation (HSCT) is associated with significant posttransplantation gonadotoxicity. This deficit has been mainly attributed to pretransplantation conditioning, but lower sperm counts in humans also appear to be associated with graft-versus-host disease (GVHD) following allogeneic HSCT. However, the mechanisms leading to diminished spermatocyte levels during GVHD remain unknown.

On the relevance of TCR rearrangement circles as molecular markers for thymic output during experimental graft-versus-host disease.

Efficient reconstitution of the pool of peripheral T cells after hemopoietic stem cell transplantation (HSCT) is dependent on normal thymic function. However, the development of graft-vs-host disease (GVHD) in the context of allogeneic HSCT is associated with injurious effects on thymocyte development. In this study, we examined in models of syngeneic and allogeneic murine HSCT whether actual posttransplant thymic output is accurately reflected by analysis of signal-joint TCR rearrangement excision circles (sjTRECs).

Keratinocyte growth factor preserves normal thymopoiesis and thymic microenvironment during experimental graft-versus-host disease.

Thymus-dependent reconstitution of the peripheral T-cell compartment is critical for the successful outcome of bone marrow transplantation. However, graft-versus-host disease (GVHD) affects thymic stromal function and thus prevents normal T-cell maturation and selection. To determine whether cytoprotection of thymic epithelial cells (TECs) by keratinocyte growth factor (KGF) averts GVHD-related injury to the thymus, a nonirradiated murine parent-->F(1) transplantation model was investigated.