Thymic-derived tolerizing dendritic cells are upregulated in the spleen upon treatment with intravenous immunoglobulin in a murine model of immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by low platelet counts. First-line treatment includes intravenous immunoglobulin (IVIg), however, its working mechanism remains incompletely understood. We investigated splenic and thymic dendritic cell (DC) subsets upon IVIg treatment in a well-characterized active murine model of ITP.

The spleen dictates platelet destruction, anti-platelet antibody production, and lymphocyte distribution patterns in a murine model of immune thrombocytopenia.

For many years, splenectomy has been used to treat immune thrombocytopenia (ITP), and this procedure benefits approximately two-thirds of the treated patients. Although splenectomy may raise platelet counts, antibody-coated platelets and cytotoxic T lymphocytes appear to persist or can change over time. To better understand how the spleen may affect anti-platelet immune responses, we used a murine model of ITP demonstrating both antibody-mediated and T lymphocyte-mediated thrombocytopenia.

Direct antiglobulin ("Coombs") test-negative autoimmune hemolytic anemia: a review.

We have reviewed the literature to identify and characterize reports of warm-antibody type, autoimmune hemolytic anemia in which the standard direct antiglobulin reaction was negative but a confirmatory test indicated that the red cells were opsonized with antibody. Three principal reasons account for the absence of a positive direct antiglobulin test in these cases: a) IgG sensitization below the threshold of detection by the commercial antiglobulin reagent, b) low affinity IgG, removed by preparatory washes not conducted at 4°C or at low ionic strength, and c) red cell sensitization by IgA alone, or rarely (monomeric) IgM alone, but not accompanied by complement fixation, and thus not detectable by a commercial antiglobulin reagent that contains anti-IgG and anti-C3. In cases in which the phenotype is compatible with warm-antibody type, autoimmune hemolytic anemia and the direct antiglobulin test is negative, an alternative method to detect low levels of IgG sensitization, use of 4°C, low ionic strength washes to prepare the cells for the direct antiglobulin test reaction to permit retention and identification of low affinity IgG antibodies, and, if the latter are uninformative, testing for sensitization with an anti-IgA, and, if necessary, an anti-IgM reagent identifies cases of warm-antibody type, immune hemolysis not verified by a commercial reagent.

Management of immune thrombocytopenic purpura in children: potential role of novel agents.

The treatment of immune thrombocytopenic purpura (ITP) in children is controversial, requiring individualized assessment of the patient and consideration of treatment options. If the platelet count is >10 000/μL and the patient is asymptomatic, a 'watch and wait' strategy is appropriate since most children with ITP will recover completely without pharmacotherapy. If therapy is indicated because of bleeding or a platelet count <10 000/μL, then treatment with glucocorticoids, intravenous immunoglobulin (IVIg), or anti-D are possible initial choices.

The paradox of the neutrophil's role in tissue injury.

The neutrophil is an essential component of the innate immune system, and its function is vital to human life. Its production increases in response to virtually all forms of inflammation, and subsequently, it can accumulate in blood and tissue to varying degrees. Although its participation in the inflammatory response is often salutary by nature of its normal interaction with vascular endothelium and its capability to enter tissues and respond to chemotactic gradients and to phagocytize and kill microrganisms, it can contribute to processes that impair vascular integrity and blood flow.

Controversies in the diagnosis and management of childhood acute immune thrombocytopenic purpura.

Acute immune thrombocytopenic purpura (ITP) occurs most commonly in young children who present with severe isolated thrombocytopenia and purpura. A marrow examination is not required unless glucocorticoids are used, lest treatment mask incipient acute lymphoblastic leukemia, but controversy exists here. The recommendations for evaluation and management remain controversial, since prospective controlled trials have not been done.

Early allogeneic stem cell transplantation for chronic myelogenous leukemia in the imatinib era: a preliminary assessment.

We have examined the role of early allogeneic hematopoietic stem cell transplantation in patients with chronic phase chronic myelogenous leukemia (CML) who enter a complete cytogenetic remission with imatinib mesylate. Three kinds of data were used to examine the effect of the outcome of current BCR-ABL inhibitor treatment compared to early allogeneic stem cell transplantation: (1) the life expectancy of the general population of the United States as a function of age, (2) the life expectancy of CML patients as a function of the age of patients treated with imatinib mesylate (imatinib) who achieve a complete cytogenetic remission, and (3) the life expectancy of patients with CML treated with matched-related or matched-unrelated stem cell transplantation as a function of age, derived from data provided by the Center for International Blood and Marrow Transplant Research (CIBMTR). We also considered separately the transplant results of the Fred Hutchinson Cancer Research Center (FHCRC), which are substantially better than the "average" outcome from the CIBMTR.

Uncommon phenotypes of acute myelogenous leukemia: basophilic, mast cell, eosinophilic, and myeloid dendritic cell subtypes: a review.

The potential of the transformed (leukemic) multipotential hematopoietic cell to differentiate and mature along any myeloid lineage forms the basis for the phenotypic classification of acute and chronic myelogenous leukemia. Although most cases of leukemia can be classified phenotypically by the dominant lineage expressed, the genotype within each phenotype is heterogeneous. Thus, covert genetic factors, cryptic mutations, and/or polymorphisms may interact with the seminal transforming genetic mutations to determine phenotype.

Physiological effects of unassembled chaperonin Cct subunits in the yeast Saccharomyces cerevisiae.

Eukaryotic chaperonins, the Cct complexes, are assembled into two rings, each of which is composed of a stoichiometric array of eight different subunits, which are denoted Cct1p-Cct8p. Overexpression of a single CCT gene in Saccharomyces cerevisiae causes an increase of the corresponding Cct subunit, but not of the Cct complex. Nevertheless, overexpression of certain Cct subunits, especially CCT6, suppresses a wide range of abnormal phenotypes, including those caused by the diverse types of conditional mutations tor2-21, lst8-2 and rsp5-9 and those caused by the concomitant overexpression of Sit4p and Sap155p.

Familial (inherited) leukemia, lymphoma, and myeloma: an overview.

We have reviewed the world's literature that addresses familial leukemia, lymphoma, and myeloma. We have catalogued the phenotypic abnormalities associated with an increased risk of developing a hematological malignancy. These syndromes, such as Fanconi anemia or familial platelet syndrome, have been well characterized and in many cases the gene responsible for the predisposition has been defined.

Early gene activation in chronic leukemic B lymphocytes induced toward a plasma cell phenotype.

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of lymphocytes that are arrested at an intermediate stage of B lymphocyte development. CLL B lymphocytes transform (mature) to a plasmacytic phenotype with loss of CD19 and CD20 and the appearance of cytoplasmic immunoglobulin when treated in vitro with phorbol esters. We have used array hybridization technology to describe gene expression patterns for untreated and tetradecanoyl phorbol acetate (TPA)-treated CLL B cells at 5, 10, and 20 min following initial TPA exposure.

Prohibitin expression is increased in phorbol ester-treated chronic leukemic B-lymphocytes.

Chronic lymphocytic leukemia (CLL) is characterized by the gradual accumulation of immature B-lymphocytes. CLL B-lymphocytes mature to a plasmacytoid phenotype when treated in vitro with phorbol esters. CLL B-cell apparent maturation is associated with altered expression of specific plasma membrane and mitochondrial proteins including heightened expression of a 30-kDa heat shock protein 60 (hsp60) analog.

Anticoagulant proteins in childhood venous and arterial thrombosis: a review.

Thrombotic disease is less frequent in children than in adults, but may result in severe morbidity and mortality. The coagulation system is balanced to provide rapid activation to stop bleeding and appropriate inhibition to prevent unwanted clot extension. It is regulated by fibrinolysis and by three major anticoagulant pathways: the protein C, antithrombin, and tissue factor pathway inhibitor systems.

Cloning of rabbit Cct6 and the distribution of the Cct complex in mammalian tissues.

Cct6 protein is one of the subunits of the Cct complex involved in ATP-dependent folding of cellular proteins. We used the cDNA of the human CCT6 subunit to obtain a full-length cDNA from a rabbit kidney cortex library. Two transcripts of 2 and 2.

Developmental biology of erythropoiesis.

A newborn infant represents the culmination of developmental events from conception through organogenesis. Red cells are critically important for survival and growth of the embryo. During development, erythropoiesis occurs in two distinct forms.

Analysis of mutationally altered forms of the Cct6 subunit of the chaperonin from Saccharomyces cerevisiae.

The Cct double-ring chaperonin complex of Saccharomyces cerevisiae is comprised of eight essential subunits, Cct1p-Cct8p, and assists the folding of substrates such as actins and tubulins. Single and multiple amino acid replacements of Cct6p were constructed by oligonucleotide-directed mutagenesis, including changes of charged to alanine residues and uncharged to charged residues. The replacements were targeted, in part, to residues corresponding to functionally critical regions identified in the published crystal structure of the Escherichia coli chaperonin, GroEL.