Human adherent cell contact-mediated modulation of normal myeloid colony formation.

The effects of coincubation of normal nonadherent bone marrow cells on adherent monolayers created from human peripheral blood mononuclear cells or marrow cells were investigated. Nonadherent marrow cells were coincubated for 4 hours with peripheral blood adherent cells at ratios of adherent cells to marrow cells of 2:1 to 5:1. This coincubation suppressed subsequent neutrophilic agar colony growth but not eosinophilic growth. Further studies suggested that this suppression was a cell-cell-mediated process and not secondary to soluble factors. However, coincubation on marrow adherent cells caused increased neutrophilic colony recovery. The possible in vivo relevance is discussed.

Nature of the delayed graft-versus-host reactivity of fetal liver cell transplants in mice.

Experiments were designed to determine which actual differences in the cellular composition between fetal liver and bone marrow account for the distinct types of graft-versus-host (GvH) disease. The assay of reactive lymphocytes (by in vitro mitogenic stimulation) in fetal liver transplants in mice, the purification of hemopoietic stem cells (HSC) of the transplants, and the quantitation of HSC numbers in the grafts traced the basis for the distinctly weak type of GvH disease after fetal liver cell grafts. It was found that transplantation of purified HSC concentrates did not modify the severity of GvH mortality. The moderate character of the delayed GvH disease was shown to depend on the presence of an HSC population in fetal liver with different qualities and not on numerical differences between the HSC in fetal liver and bone marrow. Data collected also demonstrated that when GvH disease occurred in the recipients of transplants of fetal liver, it shared the characteristic histologic features of the bone marrow GvH syndrome. The recovery of mitogen responsiveness of spleen cells may have been delayed in fetal liver allotransplantation as compared to syngeneic grafting. By supportive infusion of lymphoid cells, it was suggested that the immunodeficiency coinciding with GvH disease represented a secondary manifestation of the disease rather than a primary impairment in lymphoid differentiation.

In vitro colony formation of transplantable rat leukemias in comparison with human acute myeloid leukemia.

In vitro colony formation in two different soft agar systems was studied with bone marrow from untreated patients suffering from acute myeloid leukemia (AML) and from rats in various stages of two different transplantable myeloid leukemias. In both the thin-agar-layer system, which uses a feeder layer of fetal fibroblasts, and the Robinson culture system, human AML marrow failed to produce colonies. A similar failure was observed with the BN rat leukemia. In contrast, the Shay rat leukemic marrow produced an abnormally large number of colonies in the later stages of the disease. Evidence was obtained that the colonies produced by the Shay leukemic marrow consisted of leukemic cells, and that the disappearance of colonies from human AML and from BN rat leukemic marrow is caused by the numerical disappearance of normal pluripotent hemopoietic stem cells from the marrow and by the inability of the clonogenic leukemic cells to produce colonies in vitro. The results indicate that the BN rat leukemia is a realistic animal model for human AML.

Possible mechanisms of action of lithium on augmentation of in vitro spontaneous myeloid colony formation.

To understand the possible mechanisms of lithium carbonate-induced neutrophilia, the in vitro effect on human myeloid progenitor cells was examined. A significant increase in spontaneous colony formation (15 of 24 experiments) was observed with the addition of lithium. Increased colony formation seldom occurred when human placental conditioned media as a source of colony-stimulating activity (CSA) was simultaneously added to the cultures. Further data suggest that lithium requires an adherent marrow cell population for this action and that increases in CSA-containing cultures may be due to suboptimal CSA concentrations. Lithium was shown to release CSA from marrow cells and adherent cell population prepared from human bone marrow. Lithium possibly increases spontaneous human myeloid colony development indirectly through CSA release by adherent cells.

Effect of pretreatment with cyclophosphamide on high-dose toxicity of melphalan in mice.

This study was undertaken to evaluate the effect of pretreatment (or priming) with cyclophosphamide (CY) on lethal toxicity of high-dose melphalan (MELPH) in mice. In C57BL/6 X DBA/2 F1 (hereafter called B6D2F1) mice given an injection of a single dose of CY, 50 mg/kg, 1-5 days before MELPH, 20 mg/kg, improved survival was noted in only one of five experiments. Reducing the challenge dose of MELPH to 17 mg/kg did not improve survival consistently. Priming with CY, 50 mg/kg, 3 days before a dose of MELPH, 20 mg/kg, did not improve survival in CBA/J or C57BL/6 mice. These results indicate that CY is an inconsistent priming agent for abrogating high-dose MELPH toxicity in mice. A slightly earlier recovery of regenerating hemopoietic and of jejunal crypt cells was noted in CY-primed B6D2F1 mice given injections of a low dose of MELPH, 15 mg/kg. The occasional improved animal survival noted in CY-primed B6D2F1 mice might be related to this earlier cell recovery.

Piperazinedione, total body irradiation, and autologous bone marrow transplantation in chronic myelogenous leukemia.

Eleven patients with Philadelphia chromosome (Ph1)-positive chronic myelogenous leukemia (CML) in blast crisis (ten patients) or accelerated disease (one patient) were treated with piperazinedione (PIP) and fractionated total body irradiation (TBI) followed by autologous bone marrow transplantation (ABMT). Three patients were transplanted with marrow from which the Ph1 clone had been eradicated by prior intensive chemotherapy. All patients responded with disappearance of blasts in bone marrow and peripheral blood. Six patients achieved a second chronic phase lasting 3 to 14 months (median, 6 months). Two patients had incomplete recovery, and three patients failed to engraft and died from infection. Transplantation with Ph1-negative bone marrow did not improve response duration or survival. Recurrence of blast crisis and incomplete engraftment continue to be the two major problems in this patient group, and more active regimens need to be investigated.

Yttrium 90-labeled antiferritin followed by high-dose chemotherapy and autologous bone marrow transplantation for poor-prognosis Hodgkin's disease.

PURPOSE: This study was undertaken to examine the feasibility of combining radiolabeled antibody therapy with high-dose chemotherapy followed by autologous bone marrow transplantation in patients with poor-prognosis Hodgkin's disease. PATIENTS AND METHODS: Patients were entered onto this protocol if they had chemotherapy-resistant disease, bulky disease, or extensive prior therapy. Patients received yttrium-labeled antiferritin on day -13, -12, or -11, followed by high-dose cyclophosphamide, carmustine, and etoposide (CBV) on days -6 to -3, and then bone marrow infusion on day 0. RESULTS: Twelve patients received both radiolabeled antibody and high-dose chemotherapy followed by autologous transplantation. Two additional patients started the study, but were unable to complete all therapy. Four of 12 patients experienced early transplant-related mortality. Four patients are alive more than 2 years following transplantation and three are free from disease progression at 24+, 25+, and 28+ months following transplantation. The progression-free survival rate at 1 year is estimated to be 21%. Considering the poor prognostic characteristics of these patients, toxicity on this protocol was not necessarily greater than that observed with high-dose chemotherapy alone. CONCLUSION: This report demonstrates the feasibility of combining radiolabeled antibody therapy with high-dose chemotherapy and autologous bone marrow transplantation.

Prognostic factors for response and survival after high-dose cyclophosphamide, carmustine, and etoposide with autologous bone marrow transplantation for relapsed Hodgkin's disease.

Sixty-one patients with relapsed Hodgkin's disease who had failed a mechlorethamine, vincristine, procarbazine, and prednisone (MOPP)- and a doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD)-like regimen were treated with a high-dose combination chemotherapy containing cyclophosphamide, carmustine, and etoposide (CBV) and autologous bone marrow transplantation (ABMT). Fifty-nine patients were treated in relapse and two were intensified early in third remission. Following therapy, 29 patients (47%) were in complete remission (CR), 18 patients (30%) achieved a partial response (PR), and 14 patients (23%) had progressive disease (PD). Among the partial responders, six patients achieved a CR following addition of local radiation therapy to sites of residual nodal disease. For a minimum follow-up of 2 years, 23 patients (38%) are alive and free of disease. High-dose CBV therapy produced severe myelosuppression, and there were four (7%) treatment-related deaths. A multivariate analysis identified failure of more than two prior chemotherapy treatments and poor performance status as important adverse risk factors for survival. Patients who had no adverse risk factor and/or were intensified with CBV while Hodgkin's disease was still responding to conventional chemotherapy, had a CR rate of 63%, with 77% projected 3-year survival; whereas, all other patients had a CR rate of 31%, and a projected 3-year survival of only 18%. Our results demonstrated that CBV and ABMT can induce remission duration of 2 years or greater in a significant proportion of patients with relapsed Hodgkin's disease.

Proto-oncogene expression in human normal bone marrow.

We and other investigators have previously reported our findings on oncogene expression in human leukemia in an attempt to study the possible involvement of these genes in the leukemic state. An important shortcoming of these studies has been the lack of information on the expression of these genes in normal hematopoietic cells. To address this question we analyzed both the transcript size and level of expression of six oncogenes in fresh hematopoietic cells obtained from hematologically normal individuals and compared the results to those found in fresh samples obtained from patients with various forms of leukemia (acute myelogenous leukemia, acute lymphocytic leukemia, and chronic myelogenous leukemia). We found low level expression of c-myc, c-myb, c-fes, and c-raf in normal bone marrow in sharp contrast to the high levels of expression found in some forms of leukemia. C-fos was highly expressed in both normal bone marrow and certain leukemias. We were unable to detect c-sis expression in our normal samples. With the exception of c-fes, there was no variation in transcript size when comparing normal and leukemic samples. Having defined the transcript sizes and levels of expression for these proto-oncogenes in normal hematopoietic cells, we know that aberrant transcript size for the genes we have studied is not a common event in leukemias. The levels of expression, however, vary widely between normal hematopoietic cells and leukemia as well as between different types of leukemia.

HLA-identical sibling bone marrow transplants vs chemotherapy for acute myelogenous leukemia in first remission.

There is controversy whether adults with acute myelogenous leukemia (AML) in first remission are best treated with chemotherapy or an HLA-identical sibling bone marrow transplant. We studied 1097 adults, 16-50 years old, with AML in first remission. Results of transplants from HLA-identical siblings reported to the International Bone Marrow Transplant Registry (IBMTR; n = 901) were compared with results of chemotherapy in comparable persons treated by the German AML Cooperative Group (GAMLCG; n = 196). Preliminary analyses identified subject- and disease-related variables differing between the cohorts and associated with treatment outcome within each cohort. We adjusted for these variables and differences in time-to-treatment in subsequent comparisons of treatment-related mortality, relapse, survival and leukemia-free survival (LFS). Five-year probability of treatment-related mortality was greater for transplants than chemotherapy (43% (95% confidence interval, 37-49%) vs 7% (3-11%); P< 0.0001). Five-year relapse probability was less for transplants than chemotherapy (24% (20-28%) vs 63% (55-71%); P< 0.0001). Five-year probability of survival was similar with transplants and chemotherapy (48% (43-53%) vs 42% (33-51%); P = 0.24). Five-year LFS probability was higher for transplants than chemotherapy (46% (42-50%) vs 35% (28-41%); P= 0.01). These data indicate that bone marrow transplants from HLA-identical siblings result in comparable survival but greater LFS than chemotherapy in adults with AML in first remission.

Chemotherapy versus transplants for acute myelogenous leukemia in second remission.

The best therapy for persons with acute myelogenous leukemia (AML) in 2nd remission is unknown. Bone marrow transplants from an HLA-identical sibling are reported to be better than chemotherapy but this is controversial. The objective of the study was to compare 3-year leukemia-free survival (LFS) in comparable subjects receiving chemotherapy or a transplant. 485 persons with AML in 2nd remission were studied. The chemotherapy cohort included 244 persons treated on trials of the British Medical Research Council, Eastern Cooperative Oncology Group and MD Anderson Hospital. The transplant cohort included 257 persons transplanted worldwide and reported to the international Bone Marrow Transplant Registry (16 were also chemotherapy subjects.) Subjects were selected for comparable age and year of treatment. Preliminary analyses identified two factors correlated with LFS: age < or = or > 30 years and 1st remission duration < or = or > 1 year; subsequent analyses were partitioned accordingly. Three-year probabilities of treatment-related mortality with chemotherapy and transplants were 7% (95% confidence interval, 3-15%) vs 56% (49-63%). Three-year leukemia relapse probabilities were 81% (74-86%) vs 41% (33-49%). Three-year probabilities of LFS were 17% (12-23%) vs 26 (20-32%). Cohort analysis showed significantly higher LFS with transplants vs chemotherapy in persons < or = 30 years and 1st remissions > 1 year (41% (29-53%) vs 17% (7-32%); P = 0.017) and those in > 30 years with 1st remissions < or = 1 year (18% (9-29%) vs 7% (2-16%); P = 0.046). Others had comparable LFS with both treatments. These data indicate better LFS with HLA-identical sibling transplants than chemotherapy in some persons with AML in 2nd remission.

Induction of proliferation of haemopoietic stem cells in culture.

The behavior of the pluripotent haemopoietic stem cells (HSC) in liquid culture was investigated by determining CFU-S number and cell cyclinc status (by in vitro thymidine suicide) at regular intervals. The influence of fibroblast feeder cells and fibroblast conditioned medium on these parameters was investigated. Evidence was obtained for self replication of HSC in these cultures. Proliferation of HSC was found to be dependent on a humoral factor, released into the medium by fibroblasts. Separation experiments show that this stem cell activating factor (SAF) is distinct from the colony stimulating factor (CSF). Comparison of SAF with a lysate preparation of red blood cells, a product able to sustain an elevated recovery of stem cells in culture, showed a different mode of action on the persistence of HSC. The system offers an approach to the in vitro study of regulation at the level of HSC self generation.

Effects of fibroblasts on the growth of erythroid progenitor cells in vitro.

The effect of embryo fibroblasts on the growth of erythroid colony-forming cells in vitro (CFU-e) from mouse bone marrow was investigated. First, the maintenance of CFU-e number in suspension culture was assayed. CFU-e recovered from suspension culture fell rapidly to values below 30% of the initial number. When erythropoietin (EP) was added, the initial decline during the first day was followed by a rise to 80%. In cultures supplemented with irradiated fibroblasts, the number of CFU-e did not show an abortive fall, but there was a slight increase during 3 days of culturing. The influence of fibroblasts on the colony-forming ability of CFU-e was studied in a semisolid culture system composed of an agar underlayer and a methylcellulose overlayer. The number of erythroid colonies scored after 5 days of culture in the presence of different levels of EP was proportional to the number of added fibroblasts and the colony size (depending on the number of fibroblasts) increased to macroscopic dimensions. Fibroblasts alone, without EP, induced colony formation by CFU-e if added in concentrations of 1 X 10(5) or higher. EP was not detectable in medium conditioned by the fibroblasts. These data indicate that fibroblasts may stimulate erythroid colony formation (in the absence of EP) and enhance the colony-forming ability of CFU-e in the presence of EP. From these results, it is suggested that fibroblasts exert proliferation activating effects on CFU-e target cells.

Hematologic side effects of radiolabeled immunoglobulin therapy.

Radiolabeled immunoglobulin therapy (RIT) is a new cancer treatment that is more selective than its predecessors. Its dose-limiting normal tissue side effect is bone marrow toxicity, and hematopoietic stem cell damage appears to be its most significant mechanism. Platelet consumption in irradiated normal liver tissues and apoptosis of circulating peripheral blood lymphocytes are other, less important, hematologic side effects. 131I and 90Y are the radioisotopes most commonly used for RIT; in addition, animal toxicology and initial clinical studies of chelate immunoglobulins radiolabeled with 111In (for diagnosis) or 90Y (for therapy) are reviewed. The bone-seeking properties of free 90Y are not considered to be a major component of the hematologic damage caused by yttrium-labeled immunoglobulins. The microenvironment of the bone marrow system is not significantly damaged by current RIT protocols. Moreover, granulocyte colony-stimulating factor (G-CSF) can open the blood-marrow barrier. Bone marrow toxicity after RIT can be corrected by bone marrow transplantation, growth factors, blood products, or fractionation of RIT. Selection of the appropriate corrective regimen depends on the severity of the bone marrow damage and will further enhance the therapeutic ratio of RIT.

Mobilization of murine hemopoietic stem cells (HSC) by Pyran Copolymer.

Pyran Copolymer, divinyl-ether maleic anhydride increases the concentration of circulating pluripotential stem cells in mice by a factor of 15 to 30. Maximal mobilization occurs five days after Pyran Copolymer injection with synchronous peaks of CFU-S and CFU-C. When Pyran fractions of defined molecular weight from 12,000 to 52,000 are injected into mice, mobilization of CFU-S and CFU-C parallels molecular weight. Hemopoietic stem cells are mobilized from bone marrow into peripheral blood and subsequently trapped in the spleen.

One-step procedure for human T-lymphocyte colony growth and its regulation by T and B cells, and monocytes.

Previous systems for cloning human T-cells have been either one step procedures with small colony size (40 less than 40 cells) or two-step procedures with agglutination problems. These systems also require erythrocytes, thiols and human serum. We have regularly grown more than 10(3) colonies (more than 40 cells)/5 X 10(5) cells from purified T-cells or phagocytic and adherent cell depleted mononuclear cells in agar using phytohemagglutinin (PHA) as the mitogenic stimulus. The reason for the poor colony size in other single step procedures using agar may be related to cell-to-cell interaction. We found that both adherent (Ad) and phagocytic cells were suppressive of T-cell colony growth (TCCG) in donors with low or absent TCCG from whole mononuclear cells. This effect was reproduced by adding Ad cells to T-cell concentrated fractions. Both irradiated T and unirradiated enriched B-cells increased TCCG of T fractions. TCCG is possible in simple in vitro systems from both adherent and phagocytic cell depleted fractions and concentrated T-cell fractions. This allows for the examination of factor regulation of TCCG and has enabled the identification of a possible B-cell released T-cell growth factor. Previously described complex growth requirements may be related to cell interactions.

The myeloid progenitor cell: a parallel study of subpopulations in human marrow and peripheral blood.

Ten persons who had no evident hematologic disorder or previous history of chemotherapy or irradiation were studied. Parallel in vitro agar cultures from marrow and peripheral blood were grown, colonies and clusters were scored and examined morphologically after 7 and 14 days of incubation. Mean marrow myeloid progenitor cell (CFUc) incidences after 7 and 14 days were 76 +/- 55.4 S.D. and 37.3 +/- 22.0 S.D. per 10(5)ficoll-hypaque interface cells respectively. Most of the colonies on day 7 were neutrophilic (median 86%). Eosinophil colonies made up only a minority (0%-2%) of the total number of colonies. By day 14 a decrease in neutrophil colonies (median 6%) and a rise in eosinophil colonies (median 37%) was observed. Most of the colonies on day 14 were mixed neutrophil-macrophage colonies (median 55%). Parallel studies from blood revealed no colony growth on day 7 except on one occasion. The mean cluster incidence was 1.1 +/- 0.9 S.D. per 10(5) mononuclear cells. Most of these colonies were identified as eosinophilic (median 83%). The relative incidence of various subpopulations of myeloid progenitor cells in marrow and blood is different. Cluster transplantation from peripheral blood cultures strongly suggests the possibility for separate eosinophil progenitor cells. However a possibility of a rare occurrence of bipotent neutrophil-eosinophil colony forming cell can not be completely excluded.

Adherent cell-mediated inhibition of human leukemic myelopoiesis.

We investigated the possibility that the control of leukemic growth by autologous adherent marrow cells may explain the indolent behavior of oligoleukemia. Leukemic cluster growth was measured by in vitro agar culture. The following marrow fractions (Fr) were examined from 13 patients for leukemic growth: Fr I: ficollisopaque interface cells (density less than 1.077 g/ml); Fr II: adherent-cell depleted Fr I (4.8% +/- 2.1 (SE) monocytes); Fr III: adherent and phagocytic cell depleted Fr I (0.3% +/- 0.2 monocytes); and Fr IV: adherent cells removed from plastic surfaces by lidocaine plus EDTA (74% +/- 10.9 monocytes). Two patient groups were recognized: Group A showed cluster growth in Fr IV with no absolute increase in Fr III and no suppression of Fr III cluster growth with addition of Fr IV. In Group B, Fr III showed an absolute increase in cluster growth. Fr IV did not show cluster growth and addition of Fr IV to Fr III suppressed growth. This suggested that in Group B, monocytes may suppress leukemic growth, the failure to observe this in Group A indicated the possible leukemic nature of the adherent cell fraction and the absence of residual normal monocytes. Other possible explanations are discussed.

Myelopoietic enhancement by immunoadjuvants: in vitro studies for their rational use in neutropenic patients.

Following marrow transplantation, the clinical course of the patients is invariably complicated by severe infections due to neutropenia and immuno-incompetence. With a view to explore means of alleviating these complications, Bacillus Calmette-Guerin (BCG), methanol extraction residue of BCG (MER), Corynebacterium parvum (C. parvum) and Pyran were examined for their myelopoietic activity on human marrow. Light density (less than or equal to 1.077 g/ml) unfractionated (UF) cells (2 X 10(6)/ml and 2ml/dish), and adherent (Ad) and non-adherent (N-Ad) cells alone (derived from 4 X 10(6) UF cells per dish) were incubated with and without the above agents. The conditioned media (CM) were harvested at 24, 72, 96, and 168 hours and colony stimulating activity (CSA) assayed against light density non-adherent human marrow cells using double layer agar-culture system. CSA was maximum at 72 and 96 hours followed by an invariable decline at 168 hours' incubation. The optimal concentrations releasing maximum CSA varied for each agent. CM prepared with higher concentrations were less active. CM prepared in the presence of Pyran had no CSA. Comparisons of the maximally released CSA by the optimal concentrations of these agents revealed BCG and MER to be the most active. The CSA elaborated by UF cells was more than the total combined activity from separately incubated Ad and N-Ad cells. Re-addition studies revealed that almost full CSA could be recovered when Ad and N-Ad cells were incubated together at a ratio of 1:3. Different immunoadjuvants have a differing capacity to elaborate CSA from human marrow cells and each has an optimal concentration for maximum CSA release. This may require a cell-cell and/or humoral interaction(s) between Ad and N-Ad cells.

High dose chemotherapy with autologous bone marrow transfusion.

Details are given of response and toxicity after high dose chemotherapy followed by autologous bone marrow infusion. High dose nitrosurea therapy (600-1000 mg/m2 BCNU) was predominantly associated with hematopoietic toxicity but recovery was within 4-5 weeks after BCNU therapy. High dose combination chemotherapy using cytoxan, VP-16-23 and +/- BCNU produced a response rate of approximately 80% (CR + PR + less than PR) of usually short duration in 18 evaluable patients, 17 of whom were previously treated. Hematopoietic recovery was usually complete in 4 weeks. Initial experience with the hematopoietic toxicity experienced after high dose mitomycin and ABMT is also detailed. Future proposals utilizing high dose chemotherapy with ABMT in selected tumors is presented with associated rationale.