Prevention of refractoriness and HLA-alloimmunization using filtered blood products

Depletion of leukocytes from all blood products may decrease the incidence of alloimmunization to HLA antigens present on the white cells and thus delay the onset of refractoriness to random donor platelet support. In order to test this hypothesis, 54 patients with hematologic malignancy or marrow aplasia were entered on a prospective randomized trial using cotton-wool filtration as a method of leukocyte depletion of red cell and platelet concentrates. Forty patients were considered evaluable; 20 patients received filtered products and 20 patients in the control group received standard unfiltered products. The filter was 99% efficient in removal of leukocytes (average number of WBC/platelet product, 6 X 10(6)). Platelet loss by this technique was 8%. Alloimmunization was assessed by detection of de novo formed lymphocytotoxic and platelet specific antibodies by microcytotoxicity test, Staph A protein radioimmunoassay, and solid phase red cell adherence test. In the group receiving filtered products, three of 20 (15%) patients developed lymphocytotoxic antibodies while ten of 20 (50%) patients in the control group developed cytotoxic antibodies (P = .01 by actuarial methods). Platelet antibodies were detected in seven of ten alloimmunized patients in the control group and three of three patients in the study group. Clinical evidence of refractoriness was seen in three of 20 patients in the filtered group and ten of 20 in the control group (P = .01 by actuarial methods). The cost of filtration was a fraction of the cost of a plateletpheresis product. Filtration appears to be an effective and economical method for reducing alloimmunization and clinical refractoriness to random donor platelets in patient receiving long-term transfusion support.     

Transforming growth factor beta selectively inhibits normal and leukemic human bone marrow cell growth in vitro

The effects of transforming growth factor beta 1 or beta 2 (TGF-beta 1 or -beta 2) on the in vitro proliferation and differentiation of normal and malignant human hematopoietic cells were studied. Both forms of TGF- beta suppressed both the normal cellular proliferation and colony formation induced by recombinant human interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF). In the presence of GM-CSF or IL-3, optimal concentrations of TGF-beta (400 pmol/L) inhibited colony formation by erythroid (BFU-E), multipotential (CFU-GEMM), and granulocyte-macrophage (CFU-GM) progenitor cells by 90% to 100%, whereas granulocyte or monocyte cluster formation was not inhibited. In contrast, neither form of TGF-beta had any effect on G- CSF-induced hematopoiesis. The suppressive action appeared to be mediated directly by TGF-beta since antiproliferative responses were also observed in accessory cell-depleted bone marrow cells. In contrast to normal bone marrow cells, both GM- and G-CSF-induced proliferation of cells from patients with chronic myelogenous leukemia were suppressed in a dose-dependent manner by TGF-beta. Differential effects of TGF-beta on the proliferation of established leukemic lines were also observed since most cell lines of myelomonocytic nature studied were strongly inhibited where erythroid cell lines were either insensitive or poorly inhibited by TGF-beta. These results suggest that TGF-beta is an important modulator of human hematopoiesis that selectively regulates the growth of less mature hematopoietic cell populations with a high proliferative capacity as opposed to more differentiated cells, which are not affected by TGF-beta.     

Induced expression of c-fms in normal hematopoietic cells shows evidence for both conservation and lineage restriction of signal transduction in response to macrophage colony-stimulating factor

Retrovirus-mediated gene transfer was used to obtain expression of the macrophage colony-stimulating factor (MCSF) receptor, c-fms, on hematopoietic lineages that normally do not express this receptor. Cultures of murine fetal liver cells infected with the c-fms retrovirus developed erythroid colonies in cultures stimulated with M-CSF. However, these colonies were fewer and less hemoglobinized than colonies in parallel cultures stimulated by erythropoietin. Culture of isolated clones demonstrated a direct action of M-CSF on erythroid clones. Culture of c-fms retrovirus-infected adult murine bone marrow cells showed megakaryocyte and novel macrophage-megakaryocyte clones when stimulated by M-CSF. Culture of isolated clones again confirmed a direct action of M-CSF on megakaryocyte clones. In contrast, M-CSF stimulation of c-fms-infected granulocytes and granulocyte progenitor cells did not elicit proliferation, enhanced survival, or functional stimulation of granulocytes. These findings provide evidence for both conservation and lineage restriction of signal transduction in normal hematopoietic cells.     

Platelets express a membrane protein complex immunologically related to the fibroblast fibronectin receptor and distinct from GPIIb/IIIa

We have previously identified and characterized a membrane glycoprotein complex (GP150/135) that functions as fibronectin receptor (FN-R) in fibroblast adhesion. Here we report that an immunologically related protein complex is expressed at the surface of human platelets. Antibodies monospecific for the smaller subunit (GP135) of the fibroblast FN-R in fact specifically stained the platelet surface, as determined by FACS analysis, and reacted with a component of molecular weight (mol wt) 138,000 as shown in western blots of platelet membranes. Moreover, the same antibodies precipitated the 138,000 component together with a 160,000 protein, suggesting that the two molecules are associated in a supramolecular complex. A comparative analysis indicated that this protein complex is distinct from the GPIIb/IIIa complex, known to function as a receptor of wide specificity for fibrinogen, fibronectin, and von Willebrand factor. Differential extraction experiments revealed that the platelet 138,000 component is an integral membrane protein.     

缺血性脑卒中的A-S-C-O(表型)分类

背景和目的:国际5国脑血管病专家提出一种新的腩卒中亚型分类法,旨在介绍完整的"脑卒中表型"分类的新观念,该分类是包括脑卒中的病因和存在的所有病因相关的疾病,并将病因疾病按严重程度分成3级.     

Spectrum and origin of phenylketonuria mutations in Spain

In order to characterize the molecular heterogeneity of phenylalanine hydroxylase deficiencies in the Spanish population, 37 PKU patients were initially screened for 16 known European mutations. For the remaining unidentified alleles, we used a combined strategy based on single strand conformation polymorphism analysis and DNA sequencing. Overall, a total of 15 different mutations were found in our sample, which account for 62% of the total mutant alleles. We also investigated the association between the mutations, haplotypes and variable number of tandem repeats described on the phenylalanine hydroxylase gene. In addition, we analyzed the geographical distribution in Spain of the two most prevalent mutations in our population: IVS10 and I65T.     

Evidence for B cell participation in the in vitro and in vivo maintenance of in vivo staphylococcal enterotoxin B-induced T cell anergy

The mechanisms involved in the maintenance of staphylococcal enterotoxin B (SEB)-induced T cell anergy are poorly understood. Here, we demonstrate that CD4+ T cell anergy induced by SEB treatment is under partial B cell control. This effect is not mediated by anti-SEB antibodies or any in vitro B cell-produced suppresser factor. At day 13 after SEB immunization, T cells from B cell-deficient mice proliferate upon in vitro stimulation with SEB. These results suggest that SEB- induced T cell anergy is reversible and that B cells have an important function in anergy maintenance in CD4+ T cells, both in vivo and in vitro.      

A new spontaneous mouse mutation of Hoxd13 with a polyalanine expansion and phenotype similar to human synpolydactyly

Human synpolydactyly (SPD) is an inherited congenital limb malformation caused by mutations in the HOXD13 gene. Heterozygotes are typically characterized by 3/4 finger and 4/5 toe syndactyly with associated duplicated digits; hands and feet of homozygotes are very small because of a shortening of the phalanges, metacarpal and metatarsal bones. Here we describe the phenotype and molecular basis of a spontaneous mutation of Hoxd13 in mice that provides a phenotypically and molecularly accurate model for human SPD. The new mutation, named synpolydactyly homolog (spdh), is a 21 bp in-frame duplication within a polyalanine- encoding region at the 5'-end of the Hoxd13 coding sequence. The duplication expands the stretch of alanines from 15 to 22; the same type of expansion occurs in human SPD mutations. spdh/spdh homozygotes exhibit severe malformations of all four feet, including polydactyly, syndactyly and brachydactylia. The phenotype of spdh is much more severe than that exhibited by mice with a genetically engineered, presumably null, disruption of Hoxd13. Thus spdh probably acts in a dominant-negative manner and will be valuable for examining interactions with other Hox genes and their protein products during limb development. Homozygous mice of both sexes also lack preputial glands and males do not breed; therefore, spdh/spdh mice may also be valuable in studies of reproductive physiology and behavior.