Hematopoietic Stem Cell Transplantation
Transfer of HEMATOPOIETIC STEM CELLS from BONE MARROW or BLOOD between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). Hematopoietic stem cell transplantation has been used as an alternative to BONE MARROW TRANSPLANTATION in the treatment of a variety of neoplasms.
Hematopoietic Stem Cells
Progenitor cells from which all blood cells derive.
Transplantation between individuals of the same species. Usually refers to genetically disparate individuals in contradistinction to isogeneic transplantation for genetically identical individuals.
Stem Cell Transplantation
The transfer of STEM CELLS from one individual to another within the same species (TRANSPLANTATION, HOMOLOGOUS) or between species (XENOTRANSPLANTATION), or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). The source and location of the stem cells determines their potency or pluripotency to differentiate into various cell types.
Graft vs Host Disease
Peripheral Blood Stem Cell Transplantation
Bone Marrow Transplantation
Individuals supplying living tissue, organs, cells, blood or blood components for transfer or transplantation to histocompatible recipients.
Cord Blood Stem Cell Transplantation
Identification of the major histocompatibility antigens of transplant DONORS and potential recipients, usually by serological tests. Donor and recipient pairs should be of identical ABO blood group, and in addition should be matched as closely as possible for HISTOCOMPATIBILITY ANTIGENS in order to minimize the likelihood of allograft rejection. (King, Dictionary of Genetics, 4th ed)
Hematopoietic Stem Cell Mobilization
An alkylating agent having a selective immunosuppressive effect on BONE MARROW. It has been used in the palliative treatment of chronic myeloid leukemia (MYELOID LEUKEMIA, CHRONIC), but although symptomatic relief is provided, no permanent remission is brought about. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), busulfan is listed as a known carcinogen.
The degree of antigenic similarity between the tissues of different individuals, which determines the acceptance or rejection of allografts.
Glycoproteins found on immature hematopoietic cells and endothelial cells. They are the only molecules to date whose expression within the blood system is restricted to a small number of progenitor cells in the bone marrow.
Graft vs Leukemia Effect
A progressive, malignant disease of the blood-forming organs, characterized by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow. Leukemias were originally termed acute or chronic based on life expectancy but now are classified according to cellular maturity. Acute leukemias consist of predominately immature cells; chronic leukemias are composed of more mature cells. (From The Merck Manual, 2006)
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
Bone Marrow Cells
Mesenchymal Stem Cell Transplantation
Agents that suppress immune function by one of several mechanisms of action. Classical cytotoxic immunosuppressants act by inhibiting DNA synthesis. Others may act through activation of T-CELLS or by inhibiting the activation of HELPER CELLS. While immunosuppression has been brought about in the past primarily to prevent rejection of transplanted organs, new applications involving mediation of the effects of INTERLEUKINS and other CYTOKINES are emerging.
Hepatic Veno-Occlusive Disease
Combined Modality Therapy
The treatment of a disease or condition by several different means simultaneously or sequentially. Chemoimmunotherapy, RADIOIMMUNOTHERAPY, chemoradiotherapy, cryochemotherapy, and SALVAGE THERAPY are seen most frequently, but their combinations with each other and surgery are also used.
A malignancy of mature PLASMA CELLS engaging in monoclonal immunoglobulin production. It is characterized by hyperglobulinemia, excess Bence-Jones proteins (free monoclonal IMMUNOGLOBULIN LIGHT CHAINS) in the urine, skeletal destruction, bone pain, and fractures. Other features include ANEMIA; HYPERCALCEMIA; and RENAL INSUFFICIENCY.
The developmental history of specific differentiated cell types as traced back to the original STEM CELLS in the embryo.
A nucleoside antibiotic isolated from Streptomyces antibioticus. It has some antineoplastic properties and has broad spectrum activity against DNA viruses in cell cultures and significant antiviral activity against infections caused by a variety of viruses such as the herpes viruses, the VACCINIA VIRUS and varicella zoster virus.
Leukemia, Myeloid, Acute
Clonal expansion of myeloid blasts in bone marrow, blood, and other tissue. Myeloid leukemias develop from changes in cells that normally produce NEUTROPHILS; BASOPHILS; EOSINOPHILS; and MONOCYTES.
Clonal hematopoietic stem cell disorders characterized by dysplasia in one or more hematopoietic cell lineages. They predominantly affect patients over 60, are considered preleukemic conditions, and have high probability of transformation into ACUTE MYELOID LEUKEMIA.
Stem Cell Niche
A particular zone of tissue composed of a specialized microenvironment where stem cells are retained in a undifferentiated, self-renewable state.
The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.
Embryonic Stem Cells
Graft vs Tumor Effect
Immunological rejection of tumor tissue/cells following bone marrow transplantation.
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
A general term for the complex phenomena involved in allo- and xenograft rejection by a host and graft vs host reaction. Although the reactions involved in transplantation immunology are primarily thymus-dependent phenomena of cellular immunity, humoral factors also play a part in late rejection.
A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.
Severe Combined Immunodeficiency
Group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. It is inherited as an X-linked or autosomal recessive defect. Mutations occurring in many different genes cause human Severe Combined Immunodeficiency (SCID).
The soft tissue filling the cavities of bones. Bone marrow exists in two types, yellow and red. Yellow marrow is found in the large cavities of large bones and consists mostly of fat cells and a few primitive blood cells. Red marrow is a hematopoietic tissue and is the site of production of erythrocytes and granular leukocytes. Bone marrow is made up of a framework of connective tissue containing branching fibers with the frame being filled with marrow cells.
Transplantation between genetically identical individuals, i.e., members of the same species with identical histocompatibility antigens, such as monozygotic twins, members of the same inbred strain, or members of a hybrid population produced by crossing certain inbred strains.
Precursor of an alkylating nitrogen mustard antineoplastic and immunosuppressive agent that must be activated in the LIVER to form the active aldophosphamide. It has been used in the treatment of LYMPHOMA and LEUKEMIA. Its side effect, ALOPECIA, has been used for defleecing sheep. Cyclophosphamide may also cause sterility, birth defects, mutations, and cancer.
Colony-Forming Units Assay
A cytologic technique for measuring the functional capacity of stem cells by assaying their activity.
Precursor Cell Lymphoblastic Leukemia-Lymphoma
Granulocyte Colony-Stimulating Factor
A glycoprotein of MW 25 kDa containing internal disulfide bonds. It induces the survival, proliferation, and differentiation of neutrophilic granulocyte precursor cells and functionally activates mature blood neutrophils. Among the family of colony-stimulating factors, G-CSF is the most potent inducer of terminal differentiation to granulocytes and macrophages of leukemic myeloid cell lines.
A therapeutic approach, involving chemotherapy, radiation therapy, or surgery, after initial regimens have failed to lead to improvement in a patient's condition. Salvage therapy is most often used for neoplastic diseases.
Leukemia, Myelogenous, Chronic, BCR-ABL Positive
Clonal hematopoetic disorder caused by an acquired genetic defect in PLURIPOTENT STEM CELLS. It starts in MYELOID CELLS of the bone marrow, invades the blood and then other organs. The condition progresses from a stable, more indolent, chronic phase (LEUKEMIA, MYELOID, CHRONIC PHASE) lasting up to 7 years, to an advanced phase composed of an accelerated phase (LEUKEMIA, MYELOID, ACCELERATED PHASE) and BLAST CRISIS.
A form of anemia in which the bone marrow fails to produce adequate numbers of peripheral blood elements.
The procedure established to evaluate the health status and risk factors of the potential DONORS of biological materials. Donors are selected based on the principles that their health will not be compromised in the process, and the donated materials, such as TISSUES or organs, are safe for reuse in the recipients.
Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
Antineoplastic Combined Chemotherapy Protocols
The use of two or more chemicals simultaneously or sequentially in the drug therapy of neoplasms. The drugs need not be in the same dosage form.
Mesenchymal Stromal Cells
Bone-marrow-derived, non-hematopoietic cells that support HEMATOPOETIC STEM CELLS. They have also been isolated from other organs and tissues such as UMBILICAL CORD BLOOD, umbilical vein subendothelium, and WHARTON JELLY. These cells are considered to be a source of multipotent stem cells because they include subpopulations of mesenchymal stem cells.
Multipotent Stem Cells
Specialized stem cells that are committed to give rise to cells that have a particular function; examples are MYOBLASTS; MYELOID PROGENITOR CELLS; and skin stem cells. (Stem Cells: A Primer [Internet]. Bethesda (MD): National Institutes of Health (US); 2000 May [cited 2002 Apr 5]. Available from: http://www.nih.gov/news/stemcell/primer.htm)
Stem Cell Factor
All of the processes involved in increasing CELL NUMBER including CELL DIVISION.
Any of a group of malignant tumors of lymphoid tissue that differ from HODGKIN DISEASE, being more heterogeneous with respect to malignant cell lineage, clinical course, prognosis, and therapy. The only common feature among these tumors is the absence of giant REED-STERNBERG CELLS, a characteristic of Hodgkin's disease.
Deliberate prevention or diminution of the host's immune response. It may be nonspecific as in the administration of immunosuppressive agents (drugs or radiation) or by lymphocyte depletion or may be specific as in desensitization or the simultaneous administration of antigen and immunosuppressive drugs.
Mice homozygous for the mutant autosomal recessive gene "scid" which is located on the centromeric end of chromosome 16. These mice lack mature, functional lymphocytes and are thus highly susceptible to lethal opportunistic infections if not chronically treated with antibiotics. The lack of B- and T-cell immunity resembles severe combined immunodeficiency (SCID) syndrome in human infants. SCID mice are useful as animal models since they are receptive to implantation of a human immune system producing SCID-human (SCID-hu) hematochimeric mice.
Fetal Stem Cells
Minor Histocompatibility Antigens
Allelic alloantigens often responsible for weak graft rejection in cases when (major) histocompatibility has been established by standard tests. In the mouse they are coded by more than 500 genes at up to 30 minor histocompatibility loci. The most well-known minor histocompatibility antigen in mammals is the H-Y antigen.
A pyrimidine nucleoside analog that is used mainly in the treatment of leukemia, especially acute non-lymphoblastic leukemia. Cytarabine is an antimetabolite antineoplastic agent that inhibits the synthesis of DNA. Its actions are specific for the S phase of the cell cycle. It also has antiviral and immunosuppressant properties. (From Martindale, The Extra Pharmacopoeia, 30th ed, p472)
Neural Stem Cells
Self-renewing cells that generate the main phenotypes of the nervous system in both the embryo and adult. Neural stem cells are precursors to both NEURONS and NEUROGLIA.
Formation of LYMPHOCYTES and PLASMA CELLS from the lymphoid stem cells which develop from the pluripotent HEMATOPOIETIC STEM CELLS in the BONE MARROW. These lymphoid stem cells differentiate into T-LYMPHOCYTES; B-LYMPHOCYTES; PLASMA CELLS; or NK-cells (KILLER CELLS, NATURAL) depending on the organ or tissues (LYMPHOID TISSUE) to which they migrate.
A genus of the family HERPESVIRIDAE, subfamily BETAHERPESVIRINAE, infecting the salivary glands, liver, spleen, lungs, eyes, and other organs, in which they produce characteristically enlarged cells with intranuclear inclusions. Infection with Cytomegalovirus is also seen as an opportunistic infection in AIDS.
The blood-making organs and tissues, principally the bone marrow and lymph nodes.
Mice, Inbred NOD
Induced Pluripotent Stem Cells
Cells from adult organisms that have been reprogrammed into a pluripotential state similar to that of EMBRYONIC STEM CELLS.
A malignant disease characterized by progressive enlargement of the lymph nodes, spleen, and general lymphoid tissue. In the classical variant, giant usually multinucleate Hodgkin's and REED-STERNBERG CELLS are present; in the nodular lymphocyte predominant variant, lymphocytic and histiocytic cells are seen.
Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.
Blood Group Incompatibility
An antigenic mismatch between donor and recipient blood. Antibodies present in the recipient's serum may be directed against antigens in the donor product. Such a mismatch may result in a transfusion reaction in which, for example, donor blood is hemolyzed. (From Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984).
Substances that inhibit or prevent the proliferation of NEOPLASMS.
One of a pair of excretory organs (mesonephroi) which grows caudally to the first pair (PRONEPHROI) during development. Mesonephroi are the permanent kidneys in adult amphibians and fish. In higher vertebrates, proneprhoi and most of mesonephroi degenerate with the appearance of metanephroi. The remaining ducts become WOLFFIAN DUCTS.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
The mechanism by which latent viruses, such as genetically transmitted tumor viruses (PROVIRUSES) or PROPHAGES of lysogenic bacteria, are induced to replicate and then released as infectious viruses. It may be effected by various endogenous and exogenous stimuli, including B-cell LIPOPOLYSACCHARIDES, glucocorticoid hormones, halogenated pyrimidines, IONIZING RADIATION, ultraviolet light, and superinfecting viruses.
Antineoplastic Agents, Alkylating
A class of drugs that differs from other alkylating agents used clinically in that they are monofunctional and thus unable to cross-link cellular macromolecules. Among their common properties are a requirement for metabolic activation to intermediates with antitumor efficacy and the presence in their chemical structures of N-methyl groups, that after metabolism, can covalently modify cellular DNA. The precise mechanisms by which each of these drugs acts to kill tumor cells are not completely understood. (From AMA, Drug Evaluations Annual, 1994, p2026)
A semisynthetic derivative of PODOPHYLLOTOXIN that exhibits antitumor activity. Etoposide inhibits DNA synthesis by forming a complex with topoisomerase II and DNA. This complex induces breaks in double stranded DNA and prevents repair by topoisomerase II binding. Accumulated breaks in DNA prevent entry into the mitotic phase of cell division, and lead to cell death. Etoposide acts primarily in the G2 and S phases of the cell cycle.
Blood Cell Count
Inflammation of the URINARY BLADDER, either from bacterial or non-bacterial causes. Cystitis is usually associated with painful urination (dysuria), increased frequency, urgency, and suprapubic pain.
A de novo myeloproliferation arising from an abnormal stem cell. It is characterized by the replacement of bone marrow by fibrous tissue, a process that is mediated by CYTOKINES arising from the abnormal clone.
Epstein-Barr Virus Infections
A genus of the family RETROVIRIDAE consisting of non-oncogenic retroviruses that produce multi-organ diseases characterized by long incubation periods and persistent infection. Lentiviruses are unique in that they contain open reading frames (ORFs) between the pol and env genes and in the 3' env region. Five serogroups are recognized, reflecting the mammalian hosts with which they are associated. HIV-1 is the type species.
Immunologic Deficiency Syndromes
Islets of Langerhans Transplantation
An organism whose body contains cell populations of different genotypes as a result of the TRANSPLANTATION of donor cells after sufficient ionizing radiation to destroy the mature recipient's cells which would otherwise reject the donor cells.
Proto-Oncogene Proteins c-kit
A protein-tyrosine kinase receptor that is specific for STEM CELL FACTOR. This interaction is crucial for the development of hematopoietic, gonadal, and pigment stem cells. Genetic mutations that disrupt the expression of PROTO-ONCOGENE PROTEINS C-KIT are associated with PIEBALDISM, while overexpression or constitutive activation of the c-kit protein-tyrosine kinase is associated with tumorigenesis.
A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Congenital disorder affecting all bone marrow elements, resulting in ANEMIA; LEUKOPENIA; and THROMBOPENIA, and associated with cardiac, renal, and limb malformations as well as dermal pigmentary changes. Spontaneous CHROMOSOME BREAKAGE is a feature of this disease along with predisposition to LEUKEMIA. There are at least 7 complementation groups in Fanconi anemia: FANCA, FANCB, FANCC, FANCD1, FANCD2, FANCE, FANCF, FANCG, and FANCL. (from Online Mendelian Inheritance in Man, http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=227650, August 20, 2004)
A pathologic change in leukemia in which leukemic cells permeate various organs at any stage of the disease. All types of leukemia show various degrees of infiltration, depending upon the type of leukemia. The degree of infiltration may vary from site to site. The liver and spleen are common sites of infiltration, the greatest appearing in myelocytic leukemia, but infiltration is seen also in the granulocytic and lymphocytic types. The kidney is also a common site and of the gastrointestinal system, the stomach and ileum are commonly involved. In lymphocytic leukemia the skin is often infiltrated. The central nervous system too is a common site.
Reverse Transcriptase Polymerase Chain Reaction
Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.
Polymerase Chain Reaction
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
Fetal Tissue Transplantation
Disease Models, Animal
Myeloid Progenitor Cells
A macrolide isolated from the culture broth of a strain of Streptomyces tsukubaensis that has strong immunosuppressive activity in vivo and prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro.
DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.
Family of RNA viruses that infects birds and mammals and encodes the enzyme reverse transcriptase. The family contains seven genera: DELTARETROVIRUS; LENTIVIRUS; RETROVIRUSES TYPE B, MAMMALIAN; ALPHARETROVIRUS; GAMMARETROVIRUS; RETROVIRUSES TYPE D; and SPUMAVIRUS. A key feature of retrovirus biology is the synthesis of a DNA copy of the genome which is integrated into cellular DNA. After integration it is sometimes not expressed but maintained in a latent state (PROVIRUSES).
Systemic lysosomal storage disease caused by a deficiency of alpha-L-iduronidase (IDURONIDASE) and characterized by progressive physical deterioration with urinary excretion of DERMATAN SULFATE and HEPARAN SULFATE. There are three recognized phenotypes representing a spectrum of clinical severity from severe to mild: Hurler syndrome, Hurler-Scheie syndrome and Scheie syndrome (formerly mucopolysaccharidosis V). Symptoms may include DWARFISM; hepatosplenomegaly; thick, coarse facial features with low nasal bridge; corneal clouding; cardiac complications; and noisy breathing.
Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)
Killer Cells, Natural
Bone marrow-derived lymphocytes that possess cytotoxic properties, classically directed against transformed and virus-infected cells. Unlike T CELLS; and B CELLS; NK CELLS are not antigen specific. The cytotoxicity of natural killer cells is determined by the collective signaling of an array of inhibitory and stimulatory CELL SURFACE RECEPTORS. A subset of T-LYMPHOCYTES referred to as NATURAL KILLER T CELLS shares some of the properties of this cell type.
Diseases that result in THROMBOSIS in MICROVASCULATURE. The two most prominent diseases are PURPURA, THROMBOTIC THROMBOCYTOPENIC; and HEMOLYTIC-UREMIC SYNDROME. Multiple etiological factors include VASCULAR ENDOTHELIAL CELL damage due to SHIGA TOXIN; FACTOR H deficiency; and aberrant VON WILLEBRAND FACTOR formation.
A cell-cycle phase nonspecific alkylating antineoplastic agent. It is used in the treatment of brain tumors and various other malignant neoplasms. (From Martindale, The Extra Pharmacopoeia, 30th ed, p462) This substance may reasonably be anticipated to be a carcinogen according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985). (From Merck Index, 11th ed)
Neoplastic Stem Cells
A family of receptors found on NK CELLS that have specificity for a variety of HLA ANTIGENS. KIR receptors contain up to three different extracellular immunoglobulin-like domains referred to as D0, D1, and D2 and play an important role in blocking NK cell activation against cells expressing the appropriate HLA antigens thus preventing cell lysis. Although they are often referred to as being inhibitory receptors, a subset of KIR receptors may also play an activating role in NK cells.
Bone Marrow Purging
Techniques for the removal of subpopulations of cells (usually residual tumor cells) from the bone marrow ex vivo before it is infused. The purging is achieved by a variety of agents including pharmacologic agents, biophysical agents (laser photoirradiation or radioisotopes) and immunologic agents. Bone marrow purging is used in both autologous and allogeneic BONE MARROW TRANSPLANTATION.
A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.
ABO Blood-Group System
The major human blood type system which depends on the presence or absence of two antigens A and B. Type O occurs when neither A nor B is present and AB when both are present. A and B are genetic factors that determine the presence of enzymes for the synthesis of certain glycoproteins mainly in the red cell membrane.
Cell- and Tissue-Based Therapy
Therapies that involve the TRANSPLANTATION of CELLS or TISSUES developed for the purpose of restoring the function of diseased or dysfunctional cells or tissues.
Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.
Connective tissue cells of an organ found in the loose connective tissue. These are most often associated with the uterine mucosa and the ovary as well as the hematopoietic system and elsewhere.
Polymorphic class I human histocompatibility (HLA) surface antigens present on almost all nucleated cells. At least 20 antigens have been identified which are encoded by the A locus of multiple alleles on chromosome 6. They serve as targets for T-cell cytolytic responses and are involved with acceptance or rejection of tissue/organ grafts.