Lack of autologous mixed lymphocyte reaction in patients with chronic lymphocytic leukemia: evidence for autoreactive T-cell dysfunction not correlated with phenotype, karyotype, or clinical status

In the present study, there was a complete lack of autologous MLR between responding T cells or T subsets and unirradiated or irradiated leukemic B cells or monocytes in all 20 patients with CLL, regardless of disease status, stage, phenotype, or karyotype of the disease. The stimulating capacity of unirradiated CLL B cells and CLL monocytes or irradiated CLL B cells was significantly depressed as compared to that of respective normal B cells and monocytes in allogeneic MLR. The responding capacity of CLL T cells was also variably lower than that of normal T cells against unirradiated or irradiated normal allogeneic B cells and monocytes. The depressed allogeneic MLR between CLL B cells or CLL monocytes and normal T cells described in the present study could be explained on the basis of a defect in the stimulating antigens of leukemic B cells or monocytes. The decreased allogeneic MLR of CLL T cells might simply be explained by a defect in the responsiveness of T lymphocytes from patients with CLL. However, these speculations do not adequately explain the complete lack of autologous MLR in these patients. When irradiated CLL B cells or irradiated CLL T cells were cocultured with normal T cells and irradiated normal B cells, it was found that there was no suppressor cell activity of CLL B cells or CLL T cells on normal autologous MLR. Our data suggest that the absence or dysfunction of autoreactive T cells within the Tnon-gamma subset account for the lack of autologous MLR in patients with CLL. The possible significance of the autologous MLR, its relationship to in vivo immunoregulatory mechanisms, and the possible role of breakdown of autoimmunoregulation in the oncogenic process of certain lymphoproliferative and autoimmune diseases in man are discussed.     

Molecular analysis of Polish patients with factor VII deficiency

We analyzed the mutations in patients from 10 Polish kindreds with a bleeding diathesis due to factor VII deficiency. Patients from eight families had plasma levels of factor VII coagulant activity (VII:C) and factor VII antigen (VII:Ag) that were less than 4% of normal. The coding sequence of the factor VII gene was amplified from genomic DNA by polymerase chain reaction (PCR). Sequencing demonstrated a C to T transition at position 10798 resulting in Ala294Val, a G to A transition at 10976 resulting in Arg353Gln, and a single bp deletion at 11125 to 11128 causing a frameshift mutation in the triplet encoding amino acid 404. Homozygosity for the three sequence alterations was confirmed with the restriction enzymes AvaII and MspI and allele specific PCR, respectively. A homozygous patient from a ninth family with levels of VII:C and VII:Ag of 4% and 17%, respectively, had Ala294Val and the frameshift mutation, but not Arg353Gln. Investigation of a homozygous patient from a tenth kindred with VII:C and VII:Ag of 11% and 47%, respectively, demonstrated Ala294Val and Arg353Gln, but not the frameshift mutation. Based on the above data, we conclude that the frameshift mutation in the codon for amino acid 404 is associated with marked reductions in VII:C, Arg353Gln can decrease plasma levels of factor VII in the presence of other mutations in the factor VII gene, and Ala294Val results in a dysfunctional factor VII molecule.     

Single-chain urokinase-type plasminogen activator bound to its receptor is relatively resistant to plasminogen activator inhibitor type 1

Urokinase-type plasminogen activator (uPA) is synthesized as single- chain protein (scuPA) with little intrinsic activity. scuPA is activated when it is converted to two-chain urokinase (tcuPA) by plasmin or when it binds as a single-chain molecule to its cellular receptor (uPAR). Previous data indicate that complexes between scuPA and its receptor have somewhat higher affinity for plasminogen than does tcuPA. The current study indicates that plasminogen activator activity of scuPA bound to recombinant, soluble uPAR (suPAR) is also fivefold less sensitive to inhibition by plasminogen activator type 1 (PAI-1) than is soluble or receptor-bound tcuPA. Binding of PaI-1 to suPAR/scuPA complexes is totally reversible and can be overcome by increasing the concentration of plasminogen, suggesting a competitive mechanism of inhibition (Ki = 18 nmol/L). Binding of scuPA to suPAR also retards its cleavage by plasmin. These results indicates that binding of single-chain urokinase to its receptor promotes its activity, retards its inhibition, and protects it from conversion to a two-chain form of the enzyme, a step that may precede its inactivation and clearance from cell surfaces. These results are consistent with a physiologic role for receptor-bound single-chain urokinase as a cellular plasminogen activator.     

Overexpression of cyclin D1 in the Dami megakaryocytic cell line causes growth arrest

The maturation of megakaryocytes in vivo requires polyploidization or repeated duplication of DNA without cytokinesis. As DNA replication and cytokinesis are tightly regulated in somatic cells by cyclins and cyclin-dependent kinases, we sought to determine the pattern of cyclin gene expression in cells that undergo megakaryocytic differentiation and polyploidization. The Dami megakaryocytic cell line differentiates and increases ploidy in response to phorbol 12-myristate 13-acetate (PMA) stimulation in vitro. We used Northern blotting to analyze mRNA levels of cyclins A, B, C, D1, and E in PMA-induced Dami cells and found that cyclin D1 mRNA levels increased dramatically (18-fold). Similar increases in cyclin D1 mRNA were obtained for other cell lines (HEL and K562) with megakaryocytic properties, but not in HeLa cells. The increase in cyclin D1 was confirmed by Western immunoblotting of PMA-treated Dami cells. This finding suggested that cyclin D1 might participate in megakaryocyte differentiation by promoting endomitosis and/or inhibiting cell division. To address these possibilities, we constructed two stable Zn+2-inducible, cyclin D1-overexpressing Dami cell lines. Cyclin D1 expression alone was not sufficient to induce polyploidy, but in conjunction with PMA-induced differentiation, polyploidization was slightly enhanced. However, unlike other cell systems, cyclin D1 overexpression caused cessation of cell growth. Although the mechanism by which cyclin D1 may affect megakaryocyte differentiation is not clear, these data demonstrate that cyclin D1 is upregulated in differentiating megakaryocytic cells and may contribute to differentiation by arresting cell proliferation.     

A controlled trial of recombinant human erythropoietin after bone marrow transplantation

Recombinant human erythropoietin (rHuEPO) stimulates erythropoietic bone marrow cells and increases erythrocyte production. This prospective study was designed to evaluate the effects of rHuEPO on regeneration of erythropoiesis after allogeneic or autologous bone marrow transplantation (BMT). Seventeen centers participated in this randomized, double-blind, placebo-controlled multicenter trial. The randomization was performed centrally for each center and stratified according to allogeneic or autologous BMT and major ABO-blood group incompatibility. One hundred and six patients received rHuEPO after allogeneic BMT and 109 patients received placebo. After autologous BMT, 57 patients were treated with rHuEPO and 57 with placebo. Patients received either 150 IU/kg/day C127 mouse-cell-derived rHuEPO or placebo as continuous intravenous infusion. Therapy started after bone marrow infusion and lasted until independence from erythrocyte transfusions for 7 consecutive days with stable hemoglobin levels > or = 9 g/100 mL or until day 41. After allogeneic BMT, the reticulocyte counts were significantly higher with rHuEPO from day 21 to day 42 after BMT. The median time (95% confidence intervals) to erythrocyte transfusion independence was 19 days (range, 16.3 to 21.6) with rHuEPO and 27 days (range, 22.3 to > 42) with placebo (P < .003). The mean (+/- SD) numbers of erythrocyte transfusions until day 20 after BMT were 6.6 +/- 4.8 with rHuEPO and 6.0 +/- 3.8 with placebo. However, from day 21 to day 41, the rHuEPO-treated patients received 1.4 +/- 2.5 (median, 0) transfusions and the control group received 2.7 +/- 4.0 (median, 2) transfusions (P = .004). In the follow-up period from day 42 up to day 100, 2.4 +/- 5.6 transfusions were required with rHuEPO and 4.5 +/- 9.6 were required with placebo (P = .075). A multivariate analysis (ANOVA) showed that acute graft-versus-host disease (GVHD), major ABO-blood group incompatibility, age greater than 35 years, and hemorrhage significantly increased the number of transfusions. However, after day 20, rHuEPO significantly reduced the number of erythrocyte transfusions in these patient groups, as well as reducing incompatibility in the major ABO-blood group. For the whole study period, rHuEPO reduced the transfusion requirements in GVHD III and IV from 18.4 +/- 8.6 to 8.5 +/- 6.8 U (P = .05). After autologous BMT, there was no difference in the time to independence from erythrocyte transfusions and in the regeneration of reticulocytes. Marrow purging strongly increased the requirement for transfusions as well as the time to transfusion independence.     

Effects of metoprolol on mortality and late infarction in diabetics with suspected acute myocardial infarction. Retrospective data from two large studies

From two large scale studies in patients with suspected acutemyocardial infarction we report the outcome in diabetics aftertreatment with either metoprolol or placebo. In the GoteborgMetoprolol Trial mortality at 3 months was reduced by metoprololfrom 17.9% to 7.5% and late infarction was reduced from 16.4%to 3.8%. In the MIAMI Trial, mortality was decreased by metoprololfrom 11.3% to 5.7% and the occcurence of late infarction wasdecreased from 4.5% to 31% during 15-day follow-up. Comparedwith the overall results, the effect of metoprolol on mortalityappears particularly impressive in diabetics.     

Study of constancy of hydrogen-consuming flora of human colon

The constancy of the hydrogen consuming flora of the human colon was studied in 15 healthy subjects via two measurements obtained 18 to 36 months apart. Hydrogen disappearance rate and the major products of H₂-consuming bacteria, methane and sulfide, were measured during incubation of fecal homogenates with excess hydrogen and sulfate. In 11/15, the hydrogen consumption rate and the predominant hydrogen-consuming pathway (methanogenesis, sulfate reduction, or neither) remained constant. However, major shifts in these pathways were observed in four subjects, with two losing and two gaining the ability to produce methane. Methanogenesis was associated with the highest hydrogen consumption rate. This study demonstrates that clinically unrecognizable, major alterations of the colonic flora occur in healthy subjects. Understanding of the factors responsible for these alterations might allow for therapeutic manipulation of the colonic flora.Supported in part by the Department of Veterans Affairs and NIDDKD RO1 DK 13309-25.     

Functional and metabolic studies of polymorphonuclear leukocytes in the congenital Pelger-Huet anomaly

Polymorphonuclear leukocytes (PMNL) from two individuals with congenital Pelger-Huet anomaly (PHA) were examined to determine whether functional or metabolic defects accompanied the known morphological abnormality. No abnormalities of the PHA cells, as compared to normal control cells, were found when tested for quantitative leukocyte enzyme activities, nitroblue tetrazolium reduction, hexose monophosphate shunt activity, superoxide production, generation of chemiluminescence, or iodination. The PHA cells, as compared to normal PMNL, demonstrated normal chemotaxis and random migration, as well as bactericidal activity.