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Biomedical subjects

H J Kolb

Publications and source records attributed to H J Kolb.

At least 145 records · Page 8Linked to original sources
PubMed1994

Prevention of graft-versus-host disease in DLA-haplotype mismatched dogs and hemopoietic engraftment of CD6-depleted marrow with and without cG-CSF treatment after transplantation.

Prevention of graft-versus-host disease by depletion of CD6-positive T cells was studied in the dog. Donors were DLA-homozygous, recipients DLA-heterozygous with one DLA haplotype identical to the donor. Seven control dogs received untreated marrow and died of GvHD after full hemopoietic recovery within 28 days of transplantation. For prevention of GvHD, immunomagnetic separation of T cells with a monoclonal antibody against human CD6 that crossreacted with canine T cells was evaluated. Depletion of CD6-positive cells depleted CD4-positive cells completely, but only part of CD8-positive cells and DR-positive cells. CD6-depleted marrow exhibited strong nonspecific "natural" suppression of the generation of cytotoxic T cells in vitro. Eleven dogs received CD6-depleted marrow. Only 1 dog developed GvHD and died. Sustained engraftment was seen in 8 dogs. Hemopoietic recovery was delayed and slower after transplantation of CD6-depleted marrow than after transplantation of untreated marrow. Four of these dogs were treated with G-CSF, and this accelerated the recovery of leukocytes, but did not prevent rejection. Chimerism was mixed in 7 of 10 evaluable dogs and 1 dog recovered its own hemopoiesis 2 years after transplantation. CD6 depletion prevents GvHD across a DLA-haplotype difference, but rejection and mixed chimerism may occur. Treatment with G-CSF accelerates leukocyte recovery, but cannot prevent rejection.

Animals↗
PubMed1994

Parameters of the fibrinolytic system in patients undergoing BMT: elevation of PAI-1 in veno-occlusive disease.

Veno-occlusive disease (VOD) represents one of the more frequent and most severe complications after BMT. The pathophysiology of VOD is poorly understood. To investigate a possible link between endothelial cell damage and VOD, tissue plasminogen activator (tPA) and its inhibitor (PAI-1) were measured in 32 patients as endothelial cell-derived parameters of the fibrinolytic system. A nearly fivefold increase (mean 103.9 ng/ml, range 22.6-582.4 ng/ml, p < 0.05) in PAI-1 levels was found in the four patients who developed VOD compared with patients without this complication (mean 22.2 ng/ml, range 1.4-131.6 ng/ml). No significant difference was found in tPA levels between patient groups with or without VOD or other complications following BMT, indicating a shift of the fibrinolytic balance towards hypofibrinolysis particularly in patients with VOD. We conclude that alterations of the fibrinolytic system occur in patients undergoing BMT. Hypofibrinolysis seems to be at least one factor in the pathogenesis of VOD and the determination of PAI-1 might be helpful for diagnosing the disease. Our data also may explain the reported successful treatment of VOD by recombinant tPA.

Bone Marrow Transplantation↗
PubMed1994

Therapeutic progress and comparative aspects in chronic myelogenous leukemia (CML): interferon alpha vs. hydroxyurea vs. busulfan and expression of MMTV-related endogenous retroviral sequences in CML. German CML Study Group.

In summary, it can be expected that the availability of unrelated donors will increase the number of CML patients that can be treated curatively with allogeneic BMT. Hydroxyurea has replaced busulfan as first line treatment in CML since it prolongs survival. Ongoing randomized studies comparing IFN-based treatment regimens with standard chemotherapy or IFN-monotherapy probably will answer the question whether IFN can cure a small percentage of CML patients and whether this small percentage can be increased by additional chemotherapy. The present attempts to improve prognostic scores and to apply them to early treatment decisions will allow treatment adaptation more individually. The implications of endogenous retroviral sequences expressed in CML cells are not known now, but may be far reaching.

Bone Marrow Transplantation↗
PubMed1993

Randomized comparison of busulfan and hydroxyurea in chronic myelogenous leukemia: prolongation of survival by hydroxyurea. The German CML Study Group.

In a randomized multicenter study the influence of hydroxyurea versus busulfan on the duration of the chronic phase and on survival of chronic myelogenous leukemia (CML) was determined. In addition cross resistance and adverse reactions of the drugs were analyzed. From July 1983 to January 1991, 441 CML patients were randomized to receive hydroxyurea or busulfan. Of these, 90.7% were Philadelphia positive; 25.7% were low, 38.2% intermediate, and 36.2% high risk patients according to Sokal's score. The median survival of the busulfan treated Philadelphia-positive patients is 45.4 months and of the hydroxyurea group 58.2 months (P = .008). The survival advantage for the hydroxyurea treated patients is recognized in all risk groups. Sixty four patients reached therapy resistance before blast crisis and were crossed over to the alternative drug. The 23 patients with primary hydroxyurea had a median survival of 5.6 years, the 41 patients with primary busulfan therapy a median survival of 2.7 years (P = .02). Adverse reactions were less frequent with hydroxyurea with no severe adverse effects (lung fibrosis, long lasting bone marrow aplasia). The analysis of white blood cell counts in the course of treatment showed lower counts in the hydroxyurea patients. We conclude that hydroxyurea is superior to busulfan in therapy of CML in chronic phase and should be used as first line therapy. Busulfan may have a role as secondary therapy after hydroxyurea resistance or intolerance.

Blast Crisis↗
PubMed1993

Interferon in chronic myeloid leukemia. A workshop report.

The therapeutic efficacy of interferon-alpha (IFN-alpha) in the treatment of chronic myeloid leukemia is currently being tested in a number of institutional, interinstitutional, and international trials. There is no doubt that responses are achieved in many patients, and in a small subset complete eradication of clonogenic cells may be possible. However, it has not yet been shown that overall survival of patients treated with IFN-alpha is better than that of those treated with conventional cytoreductive drugs. There are still controversial opinions on problems such as dosages and duration of treatment, combination with cytostatic agents, definition of responses, and relevance of cytogenic and molecular data. An international workshop discussed the data on interferon therapy and attempted to define the role of interferon today in the management of chronic myeloid leukemia.

Bone Marrow Transplantation↗
PubMed1993

Identification and characterization of a mouse monoclonal antibody (M10) directed against canine (dog) CD8+ lymphocytes.

Monoclonal antibodies (mAb) were produced by immunizing BALB/c mice with non-adherent dog lymphocytes. M10 was specific for a subset of dog lymphocytes. M10 belonged to the IgG1 subclass and reacted with 26% of dog peripheral blood lymphocytes, 24% of spleen lymphocytes, 81% of thymus cells, 1.2% of bone marrow cells (5.8% of bone marrow lymphocytes) and 23% of PHA-stimulated lymphocytes. Immunohistology of snap-frozen thymus and spleen showed that the spleen B-cell area stained negative, whereas the spleen T-cell area and the thymus medulla exhibited positive reaction in 20-30%. The thymus cortex was strongly positive. M10 diminished cell lysis by 58% in cell mediated lysis assays (CML). Immunoblot assays revealed that M10 recognized an antigen with a molecular weight of 76 kD under non-reducing and 33 kD under reducing conditions. Finally, M10 bound to a canine CD8 alpha transfected rat T-cell line (NB2). These findings characterize M10 as an antibody directed against the dog CD8 antigen.

Animals↗
PubMed1993

The German CML study, comparison of busulfan vs. hydroxyurea vs. interferon alpha and establishment of prognostic score 1.

From July 1983 to January 1991 a total of 622 patients were randomized (585 eligible) to compare the effects of hydroxyurea, interferon alpha (IFN), and busulfan on the duration of chronic phase, and survival. Further goals included the determination of prognostic parameters. 598 CML patients were documented and 575 evaluable. The Ph-status was known for 547 patients. 89.4% of the patients were Ph-positive (+). 11% had additional chromosome aberrations. The median survival of Ph+ patients by now is 4.2 years, that of Ph-patients 1.4 years. Ph-negative patients are older, tend to have lower cell counts and, as a group are more ill at diagnosis. A survival difference of about one year is expected between busulfan and hydroxyurea treated patients. Prospectively evaluated age, organomegaly related symptoms, Karnofsky index, extramedullary manifestations, number of erythroblasts and percent of circulating blasts proved to be of prognostic significance. A prognostic score (score 1) was determined which was superior to Sokal's score in the study population. 164 patients were randomized to receive IFN. In 54 patients (33%) IFN had to be terminated because of adverse effects, therapy resistance or other reasons. Clinically relevant neutralizing antibodies were detected in 9 cases. Most frequent adverse events were flu-like symptoms in 74%, gastrointestinal symptoms in 52%, and neurologic-psychiatric symptoms in 30% of patients. Reduction of the Ph-chromosome was observed in 13% of evaluable patients (10 of 75). In 4 patients complete cytogenetic remissions were observed, in three of these ongoing. Cytogenetic responders have a survival advantage. Interferon treated Philadelphia-negative CML patients have no survival disadvantage. The study is expected to allow statements as to the advantages or disadvantages of the use of busulfan, hydroxyurea and IFN in the treatment of CML as well as to the reliability of prognostic markers.

Adult↗
PubMed1993

[HDL subfractions in post-prandial lipidemia].

The influence of a standardised fatty test meal on the composition of high-density lipoprotein (HDL) subfractions (HDL3, HDL2) and the concentration of other lipid parameters was investigated in a group of young women of the age 20-25 years, in women of the age range 60-90 years, and in a group of patients with arteriosclerotic diseases. Total cholesterol and HDL cholesterol in serum do not change significantly under extreme conditions of postprandial lipaemia. This is true also regarding persons in high age groups and patients with arteriosclerotic diseases. In contrast to the group of young subjects, 60-90 years old women show both elevated HDL triglyceride levels under basal conditions and a greater magnitude of HDL triglyceride enrichment under the conditions of postprandial lipaemia. Patients with arteriosclerotic diseases also exhibit a marked postprandial HDL triglyceride enrichment. It is concluded that there are metabolic relations between the observed low HDL2 cholesterol concentrations in the group of older subjects and in patients with arteriosclerotic diseases and the high magnitude of HDL triglyceride increase in the postprandial state which are relevant within the risk syndrome hypertriglyceridaemia-low HDL2 levels.

Adult↗
PubMed1992

Changing trends in allogeneic bone marrow transplantation for leukemia in the 1980s.

OBJECTIVE: To identify changes in practice and outcome of bone marrow transplants for leukemia in the 1980s. DESIGN: Comparison of key explanatory and outcome variables in five 2-year cohorts, from 1980 through 1981 to 1988 through 1989, using a large database of detailed clinical information. PATIENTS: Recipients (7788) of bone marrow transplants for acute lymphoblastic, acute myelogenous, or chronic myelogenous leukemia reported to the International Bone Marrow Transplant Registry, Milwaukee, Wis, by 185 transplant teams worldwide. RESULTS: Linear increases occurred during the periods 1980 through 1981 to 1988 through 1989 as follows with 95% confidence intervals: (1) transplants for chronic myelogenous leukemia from 14% +/- 2% to 35% +/- 2%; (2) transplants from unrelated donors from 1% +/- 1% to 7% +/- 1%; (3) preparative regimens without radiation from 3% +/- 1% to 30% +/- 2%; and (4) use of methotrexate plus cyclosporine to prevent graft-vs-host disease from 2% +/- 1% to 55% +/- 2%. Among recipients of human lymphocyte antigen-identical sibling bone marrow, the 2-year probability of treatment-related mortality decreased by 6% to 22%. The probability of relapse decreased from 46% +/- 6% to 38% +/- 6% in intermediate leukemia but did not change appreciably in early or advanced leukemia. Probabilities of leukemia-free survival improved from 51% +/- 4% to 57% +/- 3% in early leukemia, from 28% +/- 4% to 36% +/- 5% in intermediate leukemia, and from 12% +/- 4% to 18% +/- 5% in advanced leukemia. A separate analysis of a homogenous population of patients indicated that improvements in outcome in the 1980s were due to improvements in transplant practice rather than improved patient selection. CONCLUSIONS: Modest increases in leukemia-free survival rates occurred after human lymphocyte antigen-identical sibling bone marrow transplants in the 1980s. Improvements were due primarily to reductions in treatment-related mortality with little or no change in relapse risk. More effective antileukemia strategies and continued reductions in treatment-related toxic effects are needed.

Adult↗
PubMed1992

Increased levels of tissue plasminogen activator (t-PA) and tissue plasminogen activator inhibitor (PAI) correlate with tumor necrosis factor alpha (TNF alpha)-release in patients suffering from microangiopathy following allogeneic bone marrow transplantation (BMT).

Severe microangiopathy resembling thrombotic thrombocytopenic purpura (TTP) has been reported as a complication of acute graft-versus-host disease (aGvHD) in patients receiving cyclosporin (CsA) prophylaxis following allogeneic BMT. In order to analyze the pathophysiological events involved in microangiopathy, a prospective study comparing release of von Willebrand Factor (vWF), t-PA and PAI, as well as TNF alpha and further coagulation parameters was performed in 32 patients. Endothelial damage as the central lesion was confirmed by the close association of vWF and t-PA:Antigen with severity of microangiopathy. t-PA activity, however, was neutralized by a simultaneous rise in PAI. Activation of coagulation in the course of microangiopathy was further confirmed by increased levels of DDimer (DDi), fibrinopeptide A (FPA), beta-thromboglobulin (beta TG) and platelet factor 4 (PF4). As clinical grades of microangiopathy, as well as the release of t-PA:Ag and PAI were correlated with systemic release of TNF alpha our data further support our hypothesis of cytokine induced endothelial damage in clinical complications following allogeneic BMT.

Acute Disease↗