Tolerance of activated pathogenic CD4+ T cells by transcriptional targeting of dendritic cells

We have recently shown that targeted expression of myelin oligodendrocyte glycoprotein (MOG) to dendritic cells with self-inactivating-lentivirus vectors induces antigen-specific tolerance in naive antigen-specific CD4+ T cells and protects mice from experimental autoimmune encephalomyelitis (EAE). In the present study, we demonstrate that this approach also induces tolerance of activated antigen-specific CD4+ T cells and completely protects mice from passive EAE induction. Tolerance induction did not correlate with the depletion of the preactivated antigen-specific CD4+ T cells. However, upon isolation and in vitro re-stimulation at day 6 after adoptive transfer the MOG-specific CD4+ T cells from the non-tolerized mice produced large amounts of inflammatory cytokines, whereas those from tolerized mice did not. This unresponsiveness correlated with the upregulation of regulatory molecules associated with anergy and regulatory T cells (Tregs). The in vivo depletion of Tregs resulted in EAE susceptibility of the tolerized animals, suggesting that these cells have indeed a role in tolerance induction/maintenance.

Transcriptional targeting of DCs with lentiviral vectors induces antigen-specific tolerance in a mouse model of multiple sclerosis

The aim of this work was to induce permanent tolerance toward self-antigens involved in autoimmune diseases, such as multiple sclerosis (MS). We hypothesized that the stable auto-antigen presentation by dendritic cells (DCs) would tolerize auto-reactive T cells and, therefore, prevent disease development in a mouse model of experimental autoimmune encephalomyelitis (EAE), which closely resembles MS. Specifically, our strategy included the ex vivo modification of hematopoietic stem cells (HSCs) with self-inactivating (SIN) lentivirus vectors that transcriptionally target the expression of myelin antigens to DCs. As SIN lentivirus vectors support the genomic integration of transgene sequences in HSC, the transduced and transplanted HSC may provide a constant supply of antigen expressing steady-state DCs. Here, we demonstrate that targeting myelin oligodendrocyte glycoprotein (MOG) expression to DCs indeed resulted in complete and stable protection from EAE. No histological signs of EAE, such as demyelination, axonal damage, or infiltration of leukocytes in brain, spinal cord and optical nerve, were observed in tolerized mice. Tolerance induction was concomitant with the efficient deletion of MOG-specific T cells and the generation of Foxp3(+) regulatory T cells and, most importantly, directed toward a specific self-antigen while T-cell reactivity to unrelated foreign antigens was fully preserved.

Immunosuppressive therapy for kidney transplant prevents vaso-occlusive crisis in a haemoglobin SC disease patient

Although the molecular basis of sickle cell disease (SCD) is well established, the wide variability in clinical manifestations still puzzles haematologists and clinicians. Recently, SCD started to be considered by different groups as a chronic inflammatory condition, where the inflammatory tendency of each individual could drive more or less severe clinical features. Here we describe a haemoglobin SC disease patient (heterozygous to both HbS and HbC variants) that experienced several vaso-occlusive crises before underwent a successful kidney transplantation. Since then (16 years ago), she is on uninterruped immunosuppressive therapy, and do not experienced any severe vaso-occlusive crisis. Considering SCD associated morbidity as a result of exacerbated immune responses, we suggest that the immunosuppressive therapy directed to the kidney graft maintenance is actually also helping in the control of the chronic inflammatory responses associated to SCD.

TCRBV3S1 and TCRBV18 gene segment polymorphisms in Brazilian Caucasoid and Black populations

The T-cell receptor (TCR) repertoire plays an important role in shaping specific immune responses. Genetic polymorphisms at the TCR locus, in both constant and variable regions, seem to represent an important mechanism for generating inter-individual and inter-population differences. Considering the scarcity of immune parameters characterized for normal human populations, we decided to determine the frequency of two TCRBV polymorphisms (located in the TCRBV3S1 and TCRBV18 gene segments) in two ethnically distinct groups of the general Brazilian population. Both polymorphisms are related to the expression of these segments at the T-cell surface and can consequently modulate the T-cell repertoire, potentially modifying the capacity of a given individual to develop an immune response. These DNA polymorphisms were analysed in material obtained from adult, normal South-American Caucasoid and Black individuals. A total of 139 individuals were analysed for the TCRBV3S1 and 141 for the TCRBV18 gene segment polymorphisms. The data indicated statistically significant differences in allelic frequencies for the two ethnic groups analysed, suggesting that any correlation between TCR usage or T-cell repertoire and development of a given disease should take in account the ethnic origin of the population studied.

Risk of leukaemia, carcinoma, and myelofibrosis in 32P- or chemotherapy-treated patients with polycythaemia vera: a prospective analysis of 682 cases. The "French Cooperative Group for the Study of Polycythaemias"

An analysis of the risk of progression towards leukemia, carcinoma and myelofibrosis was performed in 93 patients treated by 32P alone (PVSG protocols) since 1970-1979, 395 patients over the age of 65 years treated by 32P with or without maintenance therapy using hydroxyurea (French protocol) since 1980-1994, and 202 patients under the age of 65 treated by either hydroxyurea or pipobroman since 1980. The risk of leukemia, or myelodysplasia, or lymphoma in the 32P-treated patients was 10% at the 10th year, but increase after that time to reach a value of about 30% at the 20th year, in the surviving case. This risk was not dose-related. Despite a marked reduction of the cumulative 32P dose in the patients maintained by hydroxyurea, the actuarial risk was 19% at the 10th year. In the patients treated exclusively by non radio-mimetic agents (hydroxyurea or pipobroman) a risk of 10% at the 10th year was observed. The risk of carcinoma (excluding skin cancers) was about 15% at the 10th year in the 32P-treated cases, a value similar to that generally reported by the French statistics. There was no prevalence of digestive carcinomas. In contrast, the patients receiving 32P and hydroxyurea as maintenance had an excess risk: 29% at the 10th year. In the relatively young cases treated by non radio-mimetic agents, the risk was similar in both arms: 9% at the 10th year, similar to the expected incidence at this age. The risk of myelofibrosis with myeloid metaplasia was still relatively low at the 10th year, about 15% in all arms, but increased towards a value higher than 30% in the patients surviving at the 20th year. At the present time, but in only a few cases with long-term following, no myelo-fibrosis with splenic metaplasia has been observed in the pipobroman-treated cases. The present results, which need to be confirmed (the present analysis has been done in spring 95) suggest that:-the use of non radio-mimetic agents does not protect against leukemic transformation, which may be a consequence of the disease; rather than of the treatment,-maintenance therapy after initial use of 32P increases the risk of both leukemia and carcinoma,-and hydroxyurea does not delay the risk of developing myelo-fibrosis, in comparison with 32P alone.

The very-long-term course of polycythaemia: a complement to the previously published data of the Polycythaemia Vera Study Group

The very-long-term follow-up of patients initially included in the PVSG protocols provides useful information. The excess risk of cancer after chlorambucil appears to persist for 5 years after stopping this treatment. The risk of leukaemia induced by marrow suppression (32P or chemotherapy) was marked before the 10th year, but low thereafter. Phlebotomy is unacceptable as permanent treatment because of the poor clinical tolerance and the frequency of vascular complications. This treatment is also associated with a risk of early progression towards myelofibrosis with myeloid splenomegaly. In the very long term, 15 years or more after the diagnosis, this complication is the major clinical risk, affecting almost 50% of our patients surviving at this time. The prevention of this type of complication could constitute one of the objectives of future protocols dealing with this disease.

Retinoid acid supports granulocytic but not erythroid differentiation of myeloid progenitors in normal bone marrow cells

In the new context of the use of retinoic acid (RA) therapy as an inducer of leukemic differentiation and a selective inhibitor of human myeloid leukemia cell growth, we undertook to explore the potential physiological role of retinoids on the proliferation and differentiation of normal bone marrow myeloid progenitors. The effects of continuous exposure of all-trans-RA, its naturally occurring isomer, 13-cis-RA, and its metabolite 4-oxo-all-trans-RA were studied on the growth of normal human bone marrow cells in soft agar, directly and after liquid culture. Retinoids enhanced the total number of granulocytic colony and macrocluster formation in the presence of exogenous colony-stimulating factor (n = 9). Dose-response curve were bell-shaped, with a maximal increment between concentration of 0.5 and 0.05 nM. In all cases, a concomitant decrease of macrophagic colonies was noted. The positive effect on granulocytic colony formation was observed with each of the retinoids tested (all-trans, 13-cis and 4-oxo-all-trans) (n = 5). On erythroid colony formation, all-trans-RA had the opposite effect. Constant suppression of CFU-E and BFU-E colony formation and coloring was observed in a dose-related fashion from 0.1 to 10 microM (n = 5). Thus, in granulocytic, as in erythroid colony formation, retinoids affected both proliferation and differentiation parameters. However, after short-term suspension culture in the presence of all-trans-RA, an increase of both CFU-GM and BFU-E colonies, was observed. These results suggest a specific effect of retinoids on late myeloid precursors and places retinoids as possible candidates for enhancement of normal granulocytic differentiation.

[Treatment of neutropenia in Shwachman's syndrome with granulocyte growth factor (G-CSF)]

BACKGROUND

Patients with Shwachman syndrome have neutropenia and depressed neutrophil chemotaxis and are therefore susceptible to recurrent infections. The diversity of causative microbial agents makes prevention of infection difficult. Some may be life-threatening, despite antibiotic therapy and even leukocyte transfusion.

PATIENT

A 15 day-old boy presented with a staphylococcal cutaneous abscess. Neutropenia was detected when he was 45 day-old and Shwachman syndrome was diagnosed at the age of 8 months. He was then suffering from pneumonia plus pancreatic insufficiency, metaphysical chondroplasia and short stature. Frequent infections continued through childhood, but became less frequent from the age of 11 years. At 17 years, he still had neutropenia (polymorphonuclear leukocytes less than 300/mm3) and profound depressed chemotaxis. He was given subcutaneous injections of recombinant human granulocytes colony stimulating factor (rhG-CSF), 1 microgram/kg/day, for 15 days. The polymorphonuclear count increased above 1000/mm3 during the second week of treatment, and this effect was seen again during a second course of rhG-CSF. The benefit was not sustained when treatment was discontinued.

CONCLUSION

These results confirm earlier reports of the effect of 5 micrograms/kg/day of rhG-CSF but the responses were greater and earlier. While more precise information concerning the treatment of this disease is required, rhG-CSF can be useful in patients with severe infections.

Use of liquid culture and cell cycle analysis to compare drug damage following in vitro treatment of normal human bone marrow cells with adriamycin, arabinosyl-cytosine, and etoposide

The effects of adriamycin (ADM), arabinosyl-cytosine (ARA-C), and etoposide (VP16) were studied on human bone marrow mononucleated cells using colony formation in agar, a modified liquid culture system, and flow cytometry analysis of the cell cycle. Drug concentrations tested during a 1-h incubation ranged from 0.1 to 4 micrograms/ml for ADM, from 0.3 to 30 micrograms/ml for VP16, and from 10(-7) to 10(-3) M for ARA-C. Regression analysis of the dose-response curves was used to assess the drug concentration that inhibited 90% +/- 5% (LD90) of colony growth. LD90s were 0.4 microgram/ml for ADM, 20 micrograms/ml for VP16, and 10(-4) M for ARA-C. LD90-surviving cells were cultured in liquid medium for 3 weeks. Surviving cells over this time were 13% of the control for ADM, 22% for VP16, and 95.7% for ARA-C. Although cells decreased drastically in ADM- and VP16-treated samples, granulocyte-macrophage colony-forming units (CFU-GM) per 10(5) surviving cells rose to twice the control for ADM, to 60% for VP16, and to 150% for ARA-C. Flow cytometry analysis of the cell cycle was performed at day 0 and at day 4 after treatment with the LD90 dose. It showed a rapid and reversible effect of ARA-C on cells in the S-phase, whereas the action of VP16 concerned all cells, regardless of their cycle phase. We conclude that the direct effects of the three drugs on CFU-GM in agar are poorly predictive of hematopoietic reconstitution capacity, except for VP16. Liquid culture gives a much more accurate appraisal of the long-term damage and recovery due to anticancer drugs.

Acute leukemia and myelodysplasia in polycythemia vera. A clinical study with long-term follow-up

The analysis of 288 cases of polycythemia vera (PV) with a minimal follow-up of 10 years enabled us to study the characteristics of acute leukemia as observed in 33 patients (11.4%). In 50% of the patients (16 of 33), the malignant transformation is of the refractory anemia with excess of blasts (RAEB) type. Half of these further transform to acute nonlymphocytic leukemia (ANLL). Their life expectancy is not better than patients who abruptly develop ANLL. Leukemic transformation shows a frequency peak in the eighth year after initial evaluation in PV treated with chemotherapy and in the 11th year in patients treated with radiotherapy. In 30% of the patients myelofibrosis, or the spent phase of PV, is present before the transformation to acute leukemia (AL). This complication is, however, part of the natural history of PV and is observed in 20% of PV patients at 10 years when leukemic transformation is absent. Marrow fibrosis can therefore not be considered as a preleukemic phase. It was also noted that the occurrence of myeloid metaplasia/myelofibrosis is more frequent and begins earlier in patients treated by phlebotomy alone, and who do not transform to leukemia. The clinical characteristics of these AL, including high frequency of partial marrow invasion, difficulties in cytologic classification, a peak incidence similar to that in patients treated by chemotherapy or radiotherapy for a prior malignancy, multiple chromosome abnormalities, and poor response to therapy are all highly suggestive of secondary leukemias.

Polycythaemia vera in young people: an analysis of 58 cases diagnosed before 40 years

Over 20 years, 58 cases of PV in young people (46 meeting the full PVSG criteria, 12 with elevated red cell volume and leucocytosis or thrombocytosis, without splenomegaly) were studied and have been followed for periods of 3-24 years. These cases represent approximately 5% of the cases of PV referred to the Department of Nuclear Medicine of St Louis Hospital during this period. They differ from older patients in the initial clinical severity, the short interval between the first symptoms and the diagnosis, frequent presentation with a life-threatening complication (two cases of hepatic vein thrombosis, six thrombotic or haemorrhagic events, six splenectomies, two abortions) and a very enlarged spleen in half the cases. However, after the initial complications, the overall survival is very long (exceeding 70%, even when including the initial complications, at 15 years). The vascular accidents occur exclusively in the phlebotomized patients, the main risk factor being the poor stability of the haematocrit. Only one acute leukaemia was observed among the 14 cases treated by radioactive phosphorus and/or alkylating chemotherapy. The most frequent late complication was evolution towards myelofibrosis. This spent phase seemed to occur earlier in patients treated by phlebotomy. On the basis of this data, we would advise the following therapeutic strategy: phlebotomies, as soon as the diagnosis is established, and a systematic long-term treatment by hydroxyurea with the hope of reducing the number of vascular complications and of delaying the evolution towards the spent phase and the myelofibrosis.

[Polyglobulia vera. Difficulties and complications of treatment by phlebotomy]

The authors report the results of phlebotomy for polyglobulia vera in a series of 73 patients eligible for inclusion in an international co-operative study. Previous studies usually gave actuarial survival curves but failed to mention the complications and discomfort associated with phlebotomy, although these are of importance in clinical practice. Most of the 73 patients were excluded on account of discomfort (20%), vascular thrombosis (almost 50%) or transformation into myelofibrosis within a mean period of 4 years (20%). Only 10% were treated with long-term phlebotomy. Although phlebotomies avoid the long-term risk of leukaemia attached to radiophosphorus or chemotherapy (20% on average after a mean delay of 12 years), they have practical limitations and their own, important risks. In patients over 65 and in those at high vascular risk, the best treatment is myelosuppression. However, younger subjects with polyglobulia vera but no vascular risk and/or thrombocytosis may benefit, at least temporarily, from phlebotomy.

Growth fraction of myelocytes in normal human granulopoiesis

The labelling index (LI) of myelocytes (M) after flash labelling of normal human bone marrow cells with [3H]-thymidine ([3H]TdR) is always lower that the LI obtained for myeloblasts (MB) and for promyelocytes (PM). This fact can be interpreted in two ways: it may mean that the duration of the G1 phase of the cell cycle is longer in M than in MB or PM, or it may mean that the proportion of cells in cycle, i.e., the growth fraction (GF), is lower in the M population than in MB or PM. The evolution of the LI and of the mean number of grains per cell was monitored in [3H]TdR-labelled normal bone marrow during in vitro incubation for 50 hr. The generation time, measured by the halving time of the mean number of grains per cell after flash labelling, was similar for M to that for MB and PM. During continuous labelling, the LI of MB and PM reached 1 and the LI value for M never rose to more than 50% of the values recorded for MB and PM after 30 hr. These findings give support to the second hypothesis, i.e., a lower GF in the M population. Good correlation was found between the LI of M and the proportion of mature polymorphonuclear cells in the bone marrow of normal subjects and of patients with chronic benign neutropenia or hyperleucocytosis. Variations in the M growth fraction could be a medium-term (2-3 days) regulatory factor in granulocyte production.

Differentiation of mixed colony-forming cells in normal human bone marrow and blood

In blood and marrow samples from ten normal adults, mixed colonies were found in agar cultures at concentrations of 4.1 +/- 3.4/10(5) mononuclear bone marrow cells, and of 4.7 +/- 4/5 X 10(5) mononuclear blood cells. Reseeding of five- to seven-day clusters of immature cells in fresh medium with 5% PHA leukocyte-conditioned medium (PHA-LCM) and 2 U erythropoietin (Epo) showed that 10(5) mononuclear cells contained as many as 42 +/- 12 CFU-mix in bone marrow and 12 +/- 7 CFU-mix in blood, i.e., ten times more than in the primary cultures. Attempts were made to discover why these potentially mixed colonies failed to develop in primary cultures. For this purpose five- to seven-day clusters of immature cells from cultures of 5 X 10(4) bone marrow cells grown with PHA-LCM, Epo, or both were reseeded in medium containing one or both stimulants. The presence of both in secondary culture gave the best CFU-mix growth, whatever the primary stimulation, i.e., more than one-third of the immature clusters gave rise to colonies of red cells and granulocyte lineages. The addition of one or both stimulants between days 7 and 14 of primary culture, however, did not increase the number of mixed colonies or give rise to late developing ones. Reseeding of colonies and clusters of 14-day primary cultures showed that at least one-third of erythroid bursts or of late-developing granulocyte colonies contained CFU-mix, but that less than 10% of 14-day clusters developed into mixed colonies. Cultures of nonadherent cells, mononuclear cells of less than 1.065/g density or with a velocity sedimentation rate of less than 6 mm/h gave the same results as the culture of total mononuclear cells; i.e., at least ten times more multipotent progenitors were found by reseeding after five to seven days than in primary cultures. We conclude that in human bone marrow and blood the physical and kinetic properties of pluripotent stem cells are similar to those of 14-day erythroid bursts and GM colonies. Under normal culture conditions, most of these cell types differentiate into one cell lineage only, and plurilineage differentiation is inhibited.

Chromosome studies in polycythemia vera patients

One hundred thirty-five polycythemia vera (PV) patients (30 untreated by chemotherapy and 105 treated) were studied cytogenetically . The incidence of clonal chromosomal abnormalities was 20.7% (28 patients in nonleukemic phase). The incidence of 20q - was 3.7% (5 patients). The presence of cytogenetically abnormal clones did not allow prediction of the evolution of the disease. In a few cases, abnormal clones disappeared at the time of later studies. Although nonrandom, the majority of clonal chromosomal abnormalities are believed to be secondary events in PV patients.

An analysis of prognostic factors in preleukemia: interest of bone marrow scintigraphy

Simultaneous bone marrow scintigraphy with 99m Technetium colloids and 111 Indium transferrin was performed on 34 cases of preleukemic anemias and was shown to be of good prognostic value. Groups of different outcome were defined: for a normal and parallel uptake of the two markers, 90% of the patients died of acute leukemia; for a low Indium and high Technetium uptake, only 1 patient out of 15 died of leukemia (P less than 0.001). Standard clinical and hematological data were of no predictive value. Iron kinetic data and CFU/GM colony growth were correlated to the scintigraphic results. Taken together, these three kinetic parameters have a good sensitivity and specificity for the prognosis of preleukemic states.

Cytogenetic studies on acute nonlymphocytic leukemias following polycythemia vera

Chromosome studies were performed on 15 patients suffering from acute nonlymphocytic leukemia (ANLL) and in one patient in a preleukemic state following polycythemia vera (PV). Clonal chromosome abnormalities that were present in all cases were clearly nonrandom and involved chromosomes #1, #5, #7, #8, #9, #11, and #21. A subdivision of ANLL into two categories occurring in the course of PV is proposed from the clinical, hematologic, and cytogenetic data: one resembling de novo ANLL with rapid initial evolution, easy classification into one group of the FAB nomenclature, and simple chromosome abnormalities; the other resembling induced leukemia, often with more progressive initial evolution, difficulty or impossibility of classification into one group of the FAB nomenclature, and complex chromosome abnormalities. The consequences for the commitment level of progenitor cell from which the leukemic clones originate are discussed.

In vivo protection of normal mouse hematopoiesis by a beta 2 blocking agent during S-phase chemotherapy

Butoxamine, a beta 2-adrenergic blocking agent, which temporarily blocks the G1-S transition of human bone marrow granulocyte precursors in vitro, was used in vivo together with 1-beta-D-arabinofuranosylcytosine (ara-C) in mice. Butoxamine alone depressed the granulocyte labeling index and granulocyte-monocyte colony-forming Cell (GM-CFC) suicide rate at a dose of 3 micrograms/g body weight. A maximum effect was produced 6 to 12 hr after injection. Butoxamine administered 8 hr before an injection of ara-C modified the proportion of GM-CFC in S phase as compared with the number found after ara-C alone. After a series of five ara-C injections, administered at intervals of 16 hr, 70% of the treated mice died within 2 weeks, whereas only 42% of mice pretreated with butoxamine 7 to 9 hr before each ara-C injection died. This difference was due to the more rapid return to normal of GM-CFC numbers and an increase in the proportion of GM-CFC and granulocyte precursors in S phase in the butoxamine-pretreated animals. These findings suggest that butoxamine may have a potential use in protecting hematopoiesis during intensive chemotherapy for cancer.

The 'spent' phase of polycythaemia vera: hypersplenism in the absence of myelofibrosis

A clinical phase (spent phase) in the course of polycythaemia vera (PV) cases is described as enlargement of the spleen in spite of treatment, frequent cytopenia of one or several lines, persistent red cell hypervolaemia with considerable increase of plasma volume, persistence of myeloid hyperplasia with no collagen myelofibrosis or osteomyelosclerosis, absence of hepatosplenic erythroblastic metaplasia, as shown by radio-iron kinetics and/or 111In-transferrin scintigraphy. The frequency of this phase was 5% in a study where it was not systematically sought, but it could in fact be greater. Its occurrence is not related to the clinical and biological parameters of PV. On the other hand, it is significantly more frequent and earlier in patients treated by phlebotomies than in those treated by myelosuppression (32P). In four of the 12 cases, this phase was rapidly followed by an acute leukaemia. In eight cases there was a 1-5 year interval before a myelofibrosis with splenic myeloid metaplasia. This evolution could at this stage be delayed by chemotherapy. The efficacy of splenectomy should be studied.

[Anemia in renal insufficiency. I--Mechanisms of anemia in patients treated with periodic hemodialysis]

Fifty-two patients with anaemia due to chronic renal insufficiency treated by haemodialysis were divided into three severity groups. Except for bi-nephrectomized patients, none of the usual criteria such as age, sex, cause of the renal disease and duration of dialysis correlated with clinical severity. Kinetic studies showed that the severity of anaemia was unrelated to the degree of haemolysis, haemoglobin function or haemodilution. Stem cells were increased in all cases, irrespective of clinical severity. However, the degree of anaemia closely correlated with the degree of erythropoietic deficiency, as measured by radio-iron kinetics. A qualitative defect (slow release of labelled cells from the bone marrow) was associated with severe quantitative erythroid defect. These data indicate that kinetic studies of erythropoiesis constitute objective methods for measuring clinical severity. They favour the theory which makes a hypothetical inhibitor of differentiation and/or proliferation of erythropoietic precursors the main cause of anaemia.

Cytosine arabinoside as a suicide agent for human colony forming cells

The fractional reduction of cloning efficiency, otherwise known as in vitro suicide, produced by HU or 3H-TdR, is considered equivalent to the fraction of colony forming cells (CFC) in S phase and is used for the evaluation of proliferation in this population. The accuracy of both agents has been discussed. We tested cytosine arabinoside (Ara-C) on normal and pathological human bone marrow GM-CFC on different parameters. A plateau of concentrations between 1 and 5 X 10(-6) M was found to be as effective as 3H-TdR in diminishing 7 to 9 day colonies. Ara-C solutions were equally effective up to 18 weeks of storage at 4 degrees C; suicide levels were unchanged between 2 X 10(5) and 5 X 10(6) cells/ml; incubation with Ara-C was not critical between 1 and 2 h. Unlike HU, Ara-C does not require strict conditions of cell concentration, incubation time or extemporaneous preparation. Compared with 3H-TdR, Ara-C is easy to handle and does not show a decrease in cell cloning with the duration of the culture suggesting a prolonged action of the drug. Results on cell killing are comparable with the three drugs on day 7 to 9 colonies and we conclude that Ara-C is a reliable agent for suicide studies on human bone marrow GM-CFC.

Prognostic value of the combined suicide level of granulocyte progenitors and the labelling index of precursors in preleukemic states and oligoblastic leukemias

Although abnormalities in granulopoiesis detected by means of bone marrow cytology, culture and kinetic studies have provided prognostic data in preleukemic states and oligoblastic leukemias, this information cannot be applied to individual cases. In order to determine the indications for treatment and the form it should take in a given case, data would be required concerning the probability of impending transformation into acute leukemia. In 45 studies involving 34 patients who were followed for 10-42 months, a combination of a rise in the proportion of granulocyte precursors in S-phase, indicated by a colony-forming cell suicide rate of over 40%, and a low labelling index of myeloblasts and promyelocytes, was always followed by the onset of acute leukemia within 10 months. Sequential studies in 13 patients revealed an increase in cluster-forming cells and in the suicide level in the second study. The changed kinetics of granulopoietic proliferation may provide an indication for chemotherapy.

Inhibitory effects of peripheral blood cells on in vitro colony formation by autologous bone marrow in aplastic anaemia: relation with response to immunosuppressive therapy

The inhibitory activity of peripheral blood lymphocytes on autologous bone marrow was studied in 27 patients with aplastic anaemia after treatment with androgen. Inhibitory activity was hard to assess in 10 patients studied during the first year of treatment. The colony count was too low to be certain of differences between the samples incubated with or without lymphocytes. Among the 17 patients who had more than 10 colonies per 2 x 10(5) mononuclear bone marrow cells, nine showed inhibitory activity by peripheral blood lymphocytes. After 12 months of androgen therapy each of these patients showing inhibitory activity of bone marrow colony forming cells by peripheral lymphocytes responded to antithymocyte globulin. None of nine patients with few colony forming cells or no inhibitory activity of lymphocytes responded to immunosuppression.

[Mechanisms and prognosis of neutropenia in Felty's syndrome. 27 cases (author's transl)]

Twenty patients with Felty's syndrome were investigated. Isotopic studies of polymorphonuclear neutrophils, bone marrow biopsies and autoradiographies, and cultures of granulous stem cells showed that neutropenia resulted from three mechanisms acting simultaneously: hypermargination of the neutrophils predominantly in the spleen, decreased production of granulocytes in the bone marrow, and peripheral hyperdestruction of the neutrophils. Anti-granulocyte antibodies were detected in 3/12 patients. Other factors present in the serum of 2/4 patients seem capable of inhibiting the growth of granulocytic stem cells. Secondary bacterial infection (77%) may explain the severity of the prognosis: 13 out of 27 patients died 4 years on average after neutropenia was diagnosed.

The use of cimetidine for the treatment of pruritus in polycythemia vera

Thirty-four patients with polycythemia vera complicated by pruritus were treated with 900 mg of cimetidine daily for 30 days and their responses to treatment were evaluated. The conditions of 15 (44%) were improved, with 12 patients stating that pruritus completely disappeared. Nineteen patients either showed no improvement or had increasing symptoms. No toxic effects were reported. The positive responses seen are encouraging and suggest that controlled studies are indicated to further evaluate the effectiveness of H2 antagonists.

Effect of beta adrenergic agonists and beta blocking agents on hemopoiesis in human bone marrow

The effect of propranolol (non specific blocking agent), acebutolol (beta 1 blocking agent), butoxamine (beta 2 blocking agent) and several beta adrenergic agonists was studied on 3H-thymidine (3H-TdR) incorporation and granulo-monocyte colony formation in agar by human bone marrow. Only butoxamine and propranolol decreased 3H-TdR incorporation by total normal bone marrow cells at concentrations above 10(-6) M for butoxamine and 10(-5) M for propranolol. Autoradiography showed that inhibition of 3H-TdR incorporation by butoxamine was slightly more pronounced on neutrophil precursors than on red cell precursors (neutrophil series LI..53 and erythroblasts .67 compared to control bone marrow cells at 10(-5) M concentration). The development of granulo-monocyte colonies in agar culture was delayed by preincubation with butoxamine at concentrations above 5 X 10(-6) M. Hydroxyurea suicide showed that this was due to a decrease in the number of CFU-C in S phase. beta 2 blocking agents are able to decrease the number of normal hematopoietic cells entering S phase. This effect is seen on both neutrophil and erythroblastic precursors and on granulo-monocyte progenitors. It could be used as a means of protecting bone marrow cells during cancer intensive chemotherapy.

Pure erythrocytosis: reappraisal of a study of 51 cases

Fifty-one cases of pure, primary erythrocytosis were identified and followed at Hôpital Saint-Louis, Paris, and compared with 350 cases of polycythemia vera (PV) observed during the same period. At the initial evaluation, these cases did not differ from PV cases with respect to age, sex ratio, degree of red cell volume increase, and clinical symptoms. They did differ by the absence of splenomegaly, granulocytosis and thrombocytosis. At a late stage of evolution only a few cases developed classical criteria of PV. From this group of apparently homogeneous cases, two subgroups evolved. Sixty percent of the cases were highly responsive to myelosuppression with 32P. The median duration of the first remission was greater than five years, the mean yearly dose of 32P was very low, and there was a low incidence of complications. The other group (40% of cases) was relatively resistant to myelosuppressive agents. The development of better methods of investigate this disorder might help in discriminating these two groups from both an etiological and pathophysiological viewpoint. The thromboembolic risk of these diseases suggests that myelosuppressive therapy should be utilized in older patients with higher risk of vascular accidents, reserving phlebotomy for younger patients and those who are shown to be resistant to 32P therapy.

Granulocyte progenitor compartments after allogeneic bone marrow grafts

Bone marrow granulocyte colony forming cells (CFU-C) were measured in HLA compatible sibling donor-recipient pairs. The regeneration of granulocytes and CFU-C compartments were also studied in order to evaluate haemopoietic recovery. The number of nucleated bone marrow cells in the donation was 23 +/- 4 X 10 cells, which recipients received (3.5 +/- 0.4) X 10(8) nucleated cells/kg and (1.19 +/- 0.32) X 10(5) CFU-C/kg. This produced a bone marrow reconstitution of (67 +/- 26) X 10(5) CFU-C/kg by day 30. There was a significant correlation between CFU-C/kg and (1) granulocyte count on day 30 (P equal less than 0.05) and (2) the first day of reappearance of neutrophils in the blood (P equal less than 0.05). These results indicate that the speed and completeness of granulocyte regeneration can be predicted by measurement of the size of the CFU-C inoculant in the bone marrow graft.

Phagocytosis of neutrophil polymorphonuclears by macrophages in human bone marrow: importance in granulopoiesis

The cytological and electron-microscopic appearance of aneutrophil phagocytosis by macrophages in normal human bone marrow is described. This feature can be observed in every normal bone marrow and is especially frequent in autoimmune disease. Bone marrrow phagocytosis of polymorphonuclear neutrophils seems to be a physiological process resulting from the random egress of neutrophils from bone marrow to blood.

Hydroxyurea suicide study of the kinetic heterogeneity of colony forming cells in human bone marrow

The kinetics of granulomonocyte colony forming cells have been studied in unfractionated normal human bone marrow by hydroxyurea suicide and in cells separated by velocity sedimentation. Sequential studies revealed two subpopulations of colony forming cells, having different sizes and different multiplication potentialities. There are large cells with a high suicide rate which develop small granulocyte and monocyte colonies during the first week of culture in semi-solid agar. Smaller cells develop larger colonies of granulocytes, monocytes and eosinophils between 2 and 3 weeks of culture. Only granulocyte progenitors have a substantial suicide rate in this small cell population. This population is also less responsive to stimulation than is the large cell class, which is a more highly differentiated progeny. The role of these different kinetics of colony forming cells is discussed in the context of the heterogeneity of the in vitro differentiation of neutrophil, monocyte and eosinophil lines.

Maintenance therapy of 32P-induced remission in polycythemia vera. A clinical trial of chlorambucil and hydroxy-urea in 109 cases

In 109 patients with polycythemia vera, previously treated by 32P without maintenance therapy, a trial was carried out to determine the best way to reduce the number of injections needed. Chlorambucil and hydroxy-urea have been used to lengthnen the remission. Both of them are well tolerated and compatible with follow-up at reasonable time intervals. Chlorambucil maintenance increases the mean duration of remission by 12 months, the best results being observed when the drug was used continuously, instead of an intermittent (3 consecutive days every fortnight) schedule. Hydroxy-urea does not produce statistically demonstrable advantage whatever it is given, continuously or intermittently. Our study shows that, if a long-term cooperative study of the possible advantage of maintenance therapy in P.V. was undertaken in the future, low-dosage maintenance by chlorambucil could be the treatment of choice.

Erythrokinetic studies in myelofibrosis: their significance for prognosis

Eighty-three patients with myelofibrosis have been studied by erythrokinetics and have been followed up until death or for at least 12 months. Because of a large plasma volume the venous haematocrit gives only a poor idea of the red blood cell volume. The red cell survival was reduced in the majority of cases but significant haemolysis was rare. The amount of haemolysis of autologous and isologous red cells was similar, suggesting an extra-corpuscular origin for the haemolysis. Plasma iron turnover was always increased, sometimes markedly, but red cell iron incorporation was reduced in 70% of cases, indicating ineffective erythropoiesis. Surface counting showed an absence on diminution of sacral iron fixation and a rapid and marked splenic uptake in more than 90% of the cases; uptake of iron by the liver occurred in half the cases, usually not very high; iron release from the spleen was absent or reduced in 67% of the cases. The degree of ineffective erythropoiesis as measured by radio-iron incorporation and release by the spleen, the amount of haemolysis, and the red cell volume were strongly correlated with prognosis. These factors enabled a more precise prediction to be made of the clinical outcome in the 2 years following the study, than the clinical data alone. A prospective study might show whether erythrokinetic studies are also useful in determining the choice of treatment.

Prognostic value of in vitro bone marrow culture in refractory anaemia with excess of myeloblasts

Bone marrow from 17 patients with refractory anaemia with excess of myeloblasts (RAEM) was cultured in methylcellulose semi-solid medium. Compared with normal bone marrow, 3 patterns of growth occurred corresponding with different clinical stages of the condition. Patients whose bone marrow grew normal colonies and those who produced a predominance of microclusters had the longest life expectance, while those who produced a predominance of macroclusters had the shortest life expectancy with a high rate of acute leukaemic transformation. Colony culture appears to be a useful prognostic tool in the condition.

Heterogeneity in human neutrophil, macrophage and eosinophil progenitor cells demonstrated by velocity sedimentation separation

Progenitor cells of neutrophils, monocyte-macrophages, and eosinophils in human marrow were enumerated in agar cultures stimulated by placental conditioned medium or white cell underlayers. Fractionation of marrow populations by velocity sedimentation showed that the profiles of neutrophil and macrophage colony-forming cells shifted from a peak of 8-9 mm/hr in 7-day cultures to a peak of 6-7 mm/hr in 14-day cultures. This shift was due to degeneration of some early colonies formed by rapidly sedimenting cells and the delayed formation of colonies by slowly sedimenting cells. Eosinophil colony formation was delayed until the second week of incubation. Further evidence of heterogeneity was the observation that rapidly sedimenting colony forming cells were more responsive to stimulation than more slowly sedimenting cells. In the macrophage and eosinophil populations, cluster-forming cells were partially segregatable form colony-forming cells. The observed heterogeneity was similar to the described previously in the mouse and suggests that separate subpopulations of progenitor cells may exist within each hemopoietic family that could possibly give rise to functionally different progeny.

The influence of circadian variations in plasma iron on the measure of plasma iron turnover

In 92 cases studied in vivo with 59Fe, the variations of plasma iron during the study were measured. Errors in calculation of plasma iron turnover of up to 25% can be made in normosideremic patients if such variations are not taken into account. In hypersideremic patients the variations of plasma iron are low or nil; in hyposideremic patients the slow variations of plasma iron concentration do not alter the rapid slope of radio-iron removal.

Cell culture studies in 19 cases of refractory aneamia: comparison of clinical data with in vivo erythrokinetic studies

A total of 19 cases of chronic refractory anaemia underwent simultaneous in vivo erythrokinetic study and in vitro bone marrow culture. They were followed up clinically for at least 2 years. Good correlation has been found between erythrokinetic data (simultaneous quantitative and qualitative disorders of erythroblastic proliferation in preleukaemic states; pure qualitative disorders in primary sideroblastic anaemia) and the results of culture of granulocyte precursors in the bone marrow (small number of colonies, reduced size of colonies in preleukaemic states; normal number and growth in non malignant refractory anaemia). It would seem thus that both examinations are of practical interest in clinical haematology, making it possible to foresee the malignant evolution of some refractory anaemias.