Growth of in vitro colony-forming cells from normal human peripheral blood leukocytes cultured in diffusion chambers

The growth of granulopoietic progenitor cells (CFU-C) in diffusion chambers during culture of peripheral blood leukocytes from 10 normal subjects has been studied. At various times after initiation of diffusion chamber culture, cells harvested from the chambers were transferred to agar culture for measurement of CFU-C concentration. Under these conditions colonies could be grown successfully in agar culture provided pronase, necessary for the chamber harvesting procedure, was first removed by careful washing. A marked increase in the number of CFU-C, up to 25-fold the initial value, was observed in 8 out of 10 subjects. Here the growth pattern was similar, independent of the initial CFU-C values, with an immediate rise to a maximum between 6 and 13 days of culture followed by a decrease. In the other two subjects the growth of CFU-C throughout the diffusion chamber culture period was very poor. The growth of CFU-C from a given individual's blood was shown to be reproducible in repeated studies in 2 subjects, one of whom showed a proliferative and the other a non-proliferative pattern. Evidence suggests that the increase in CFU-C in diffusion chambers is the result of both self-renewal of these cells and influx from a more primitive compartment, although the present data do not allow an estimate of the relative magnitude of each.     

Normal range of blood colony-forming cells (CFU-C) in humans: influence of experimental conditions, age, sex, and diurnal variations.

Blood colony-forming cells (CFU-C) and colony-stimulating activity obtained from feeder layers of peripheral blood leucocytes (leucocyte CSA) have been studies in 69 normal subjects by means of semisolid agar culture system. Groups of normal volunteers were selected according to sex and age (20 to 45 and older than 60 years) and the results compared. The mean number of circulating CFU-C was significantly lower in young women (20-45 years old) than in males over 60 years of age, but no differences were found among the other age and sex groups. Leucocyte CSA did not significantly differ among these groups. In 5 young males the blood CFU-C did not show significant variations at 8 AM and at 4 PM of the same day. When the study was repeated in 18 subjects at longer time intervals, the number of colonies showed a maximum fivefold variation. The amount of plasma and polymorphonuclear granulocytes present in our culture system did not inhibit the colony growth. In most cases, double layer cultures grow a higher number of colonies than single layer, but feeder layers of some normal subject seem to inhibit the colony growth.     

Expression of MY7 antigen on myeloid precursor cells

A murine monoclonal antibody (anti-MY7) has been developed that detects an antigen expressed by 6% of normal human bone marrow cells, including approximately 40% of myeloid colony-forming cells (CFU-C). The number of bone marrow cells and CFU-C expressing MY7 is significantly increased in regenerating bone marrow, but less than 5% of peripheral blood CFU-C express the MY7 antigen. Erythroid precursors are MY7 negative from peripheral blood and bone marrow. Thymidine suicide studies indicate that CFU-C in S-phase tend to be MY7 positive while CFU-C not in S-phase are MY7 negative. MY7 expression thus appears to identify a fraction of CFU-C that is actively proliferating.     

Collection, storage and transfusion of blood stem cells for the treatment of hemopoietic failure.

Migration of hemopoietic stem cells via the blood to sites of stem cell need is a principle that becomes established during the embryonic development of hemopoiesis and can be observed in the adult whenever bone marrow transplantations are being performed. The regular presence of stem cells in the peripheral blood lends itself to the study of their collection, storage, and use for transfusion purposes in cases of bone marrow failure. Both in dog and in man, granulocyte-macrophage progenitor cells (CFU-C) can be collected by leukapheresis from the blood in large quantities, particularly if the yield is increased by the administration of mobilizing agents such as dextran sulfate, and appear to be an indicator for the presence of stem cells. For collection and storage, a closed plastic bag system has been developed that allows the safe handling of the cells. The loss of CFU-C from freezing and thawing with DMSO as a cryoprotective agent is only 10%-20%. If frozen and thawed mononuclear leukocytes are transfused into 1200 rad whole-body X-irradiated autologous or allogeneic recipient dogs, a hemopoietic take is observed when 0.2 X 10(5) CFU-C are present among the mononuclear leukocytes (MNC). Graft-versus-host disease can be avoided in the allogeneic situation when a purified CFU-C rich cell fraction is being transfused. In man collection and storage of MNC including CFU-C is feasible and may eventually become a therapeutic tool.     

Respective influence of extrinsic and intrinsic factors on the age-related decrease of thymic secretion.

The serum level of a circulating thymic factor (FTS) described in our laboratory diminishes in mice after adult thymectomy and with age. However, thymuses from old mice, when grafted into young adult thymectomized recipients lacking circulating FTS, can still partially restore the circulating FTS level of the recipients, whereas newborn thymuses are less efficient in restoring the serum level of FTS in old recipients than in young adult thymectomized recipients. Taken together, our results suggests that in addition to an intrinsic deficiency of the thymic secretion, "environmental" factors play a role in the disappearance of circulating FTS with age, the more so since we observed in old mouse sera factors inhibiting the in vitro biologic activity of FTS, factors that are absent from young mouse sera.     

Deficient protein kinase C-dependent Na+/H+ exchanger activity in T cells from bone marrow transplantation recipients

The early Na+/H+ exchanger-mediated alkalinization of intracellular pH (pHi) was analyzed in peripheral blood T cells from 23 bone marrow transplantation (BMT) recipients (17 allogeneic and 6 autologous) and a group of 13 healthy controls, in response to stimulation of protein kinase C (PKC) with a phorbol ester. In parallel we evaluated the proliferative response of peripheral blood T cells to an anti-CD3 mAb in the presence of either IL-2 or PMA. The pHi increase (delta pHi) observed in control samples ranged from 0.14 to 0.23 pH units (X +/- SD = 0.17 +/- 0.03). In 10 allogeneic and four autologous BMT recipients the delta pHi was under the lower limit of the control range (range: 0.01 to 0.09, X +/- SD = 0.05 +/- 0.02), whereas the remaining nine cases responded similarly to control samples (range: 0.14 to 0.24, X +/- SD = 0.17 +/- 0.04). The response of the Na+/H+ antiporter to a PKC-independent osmotic stimulation appeared to be normal, thus indicating that the intrinsic Na+/H+ exchanger activity was unaltered. The anti-CD3 induced proliferative response of the group of samples displaying a suboptimal delta pHi, was significantly lower (p less than 0.01) than that detected in control samples. T cell proliferation in samples from BMT recipients displaying a normal delta pHi was undistinguishable from the control group (p greater than 0.05). Our results provide the first evidence for a defective early metabolic event, closely related to PKC activity, in T cells from BMT recipients displaying a low proliferative response to T cell mitogens.     

Effect of activated lymphocytes on the regulation of hematopoiesis: suppression of in vitro granulopoiesis by OKT8+Ia+T cells induced by alloantigen stimulation

We studied the effects of alloantigen-stimulated lymphocytes in the regulation of hematopoiesis. Alloantigen-stimulated lymphocytes were harvested on days 2 to 3, days 6 to 7, or days 9 to 10 of MLC and were tested for their effects on granulocyte/macrophage progenitor cells (CFU-C). Dose-dependent suppression of CFU-C was observed when alloantigen-stimulated lymphocytes from days 6 to 7 and days 9 to 10 MLC were added to the cultures of autologous or allogeneic bone marrow cells for CFU-C assays. Suppressive activity was detected in the T cell fraction but not in the non-T cell fraction. For further characterization of these CFU-C/suppressor cells, alloantigen-stimulated lymphocytes were treated with radiation (2000 rad) or with monoclonal antibodies against T cell subsets and complement (C) before culture. Suppressive activity was completely abolished by treatment with OKT8 or OKIa1 antibodies and C whereas suppression was retained after radiation treatment. These observations suggest that CFU-C/suppressor cells can be induced by alloantigen stimulation in MLC and that they are radioresistant OKT8+ and Ia+ T cells.     

The predominant role of the spleen in lymphocyte recirculation. II. Pre- and postsplenectomy retransfusion studies in young pigs.

Autologous blood lymphocytes from three normal pigs were labelled with 3H-uridine and retransfused before and after splenectomy. Frequent samples for up to 150 min after retransfusion were evaluated autoradiographically to determine the rate of disappearance of labelled lymphocytes from the blood. In one pig retransfusion was performed before and after sham-splenectomy. In all preoperative experiments the pattern of disappearance of labelled lymphocytes was very similar. After a first rapid decline (halving time on average 8 min) a short rise of the labelling index was observed from 10 to 15 min after retransfusion. Then a second more gradual decrease of labelled lymphocytes followed. The mean halving time during this period was less than 32 min. From 60 min onwards the labelling index remained nearly constant. Retransfusions performed 3 days after splenectomy revealed only one nearly constant decline of the labelling index (halving time on average 129 min). After sham-splenectomy the pattern of disappearance was similar to the preoperative experiment. One hour after the end of retransfusion the labelling index had decreased by three-quarters of the initial value in normal pigs and by only one-third in the splenectomized ones. These results indicate that in the pig the total rate of recirculation is at least 4 times faster with the spleen in situ than without the spleen.     

Blood leukocyte responses to extracorporal circulation. III. Long term extracorporeal circulation without and with irradiation in normal and splenectomized dogs

Long term (12-48 h) extracorporeal circulation without and with irradiation of the blood was performed in normal and splenectomized dogs in order to observe the effect of these procedures on blood leukocyte counts including CFU-C. A transient granulocytopenia and a decrease of lymphocyte count were observed. The blood CFU-C level diminished to a very low level and remained low for the whole time of the experiments. There was no significant difference between the results of procedures with or without irradiation. The similar effect of a shortened tubing system on the blood leukocyte count is also reported. Heparin infusion alone did not decrease the peripheral CFU-C concentration. The possible explanations for the observed phenomena are discussed.     

Acute leukemia in adults: assessment of remission induction with combination chemotherapy by clinical and cell-culture criteria.

Remission induction was assessed by clinical and cell-culture criteria for 65 patients with acute myelogenous leukemia (AML), 11 patients with chronic myelogenous leukemia (CML) in blast crisis and 19 patients with acute lymphoblastic leukemia (ALL). Cyclophosphamide, cytosine arabinoside and vincristine (CAV) therapy resulted in complete remission in 23 of 50 previously untreated patients with AML and in 3 of the 11 patients with CML. Fourteen patients with ALL responded to vincristine-prednisone induction therapy and two to induction therapy with CAV. The median duration of survival of the responding patients was 2.2 years, compared with 4 months for the patients who did not respond to treatment. Granulopoietic colony formation, assessed by assay of colony-forming units dependent on colony-stimulating activity in culture (CFU-C), was abnormal in 37 of 42 bone marrow aspirates from patients with AML before treatement. CFU-C concentration increased when leukocyte-conditioned medium (LCM) was added to the cultures; 13 cultures had normal or elevated CFU-C concentration with LCM. Marrow cells of patients with ALL or CML in blast crisis demonstrated a similar pattern. Serial studies of marrow CFU-C concentration of 31 patients with AML demonstrated a change to a normal pattern with successful remission induction. Results of this study suggest that administration of purified LCM to leukemic patients might increase granulocyte production from potential but unstimulated granulopoietic precursors. This therapy would lessen the probability of death from infection during remission induction.     

THE PREDOMINANT ROLE OF THE SPLEEN IN LYMPHOCYTE RECIRCULATION

Autologous blood lymphocytes from three normal pigs were labelled with ³H-uridine and retransfused before and after splenectomy. Frequent samples for up to 150 min after retransfusion were evaluated autoradiographically to determine the rate of disappearance of labelled lymphocytes from the blood. In one pig retransfusion was performed before and after sham-splenectomy. In all preoperative experiments the pattern of disappearance of labelled lymphocytes was very similar. After a first rapid decline (halving time on average 8 min) a short rise of the labelling index was observed from 10 to 15 min after retransfusion. Then a second more gradual decrease of labelled lymphocytes followed. The mean halving time during this period was less than 32 min. From 60 min onwards the labelling index remained nearly constant. Retransfusions performed 3 days after splenectomy revealed only one nearly constant decline of the labelling index (halving time on average 129 min). After sham-splenectomy the pattern of disappearance was similar to the preoperative experiment. One hour after the end of retransfusion the labelling index had decreased by three-quarters of the initial value in normal pigs and by only one-third in the splenectomized ones. These results indicate that in the pig the total rate of recirculation is at least 4 times faster with the spleen in situ than without the spleen.     

RECOVERY OF PROLIFERATING HAEMOPOIETIC PROGENITOR CELLS AFTER KILLING BY HYDROXYUREA

Two doses of 1 mg/g of hydroxyurea (HU), injected 7 hr apart into irradiated mice in which CFU-S were proliferating during marrow regeneration, killed about 90% of CFU-S. This same dose regime injected into normal female mice, with non-proliferating CFU-S killed 92 % of CFU-C, 99 % of ESC and only 30 % of CFU-S. One day after the treatment CFU-S had decreased to 50 % and remained at about this level for a further day then returned to normal values. In spleen the increase in CFU-S was delayed by a day and showed a marked overshoot. During the period that CFU-S were decreased in number they were actively proliferating. Marrow CFU-C recovered in an exponential manner with a doubling time of 16 hr. Spleen CFU-C recovered 1 day later than marrow and showed a pronounced overshoot. ESC recovered very rapidly with doubling time of 5 hr. The changes in ⁵⁹Fe incorporation into RBC, and the peripheral blood picture, were a delayed reflection of the changes in ESC and CFU-C.     

Direct stimulation of cytokines (IL-1 beta, TNF-alpha, IL-6, IL-2, IFN-gamma and GM-CSF) in whole blood: II. Application to rheumatoid arthritis and osteoarthritis.

Rheumatoid arthritis (RA) is an immune disease in which the pathological immune reaction is thought to be initiated by the presentation of an (auto) antigen or superantigen by MHC class II positive cells to CD4 T cells. These successive immunological events can be studied by the cytokines produced at the different stages. Cytokine secretion by stimulated cells in autologous diluted whole blood has allowed the study of the immune profile characteristic of rheumatoid arthritis. The pattern of RA patient whole blood cells cultured in autologous blood is characterized by hyperactivity of the mononuclear cells with high secretion of IL-1 beta, TNF-alpha and IL-6 and low production of IFN-gamma, in comparison with the normal (N) and osteoarthrosis (OA) populations. The IL-2 secretion pattern is unique, arising from production followed by consumption. This production-consumption turnover is the most elevated in the RA group. The T cells are indeed activated in rheumatoid arthritis but regulatory events suppress some of their functions. A correlation was found between the inflammatory proteins and mediators of cellular immunity and macrophagic function: IL-1 beta and the sedimentation rate; IL-6 and fibrinogen; TNF-alpha and the number of blood monocytes. The secretion of OA-stimulated whole blood cells was similar to RA for two monokines (overproduction of TNF-alpha and IL-6) and different for IL-1 beta, not different from normal in OA. Stimulated whole blood cell cytokine secretion profile from RA and OA groups, was the same as previously observed in synovial fluid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Circulating microRNAs as Biomarkers for Detection of Autologous Blood Transfusion

MicroRNAs (miRNAs) are small non-coding RNAs that regulate various biological processes. Cell-free miRNAs measured in blood plasma have emerged as specific and sensitive markers of physiological processes and disease. In this study, we investigated whether circulating miRNAs can serve as biomarkers for the detection of autologous blood transfusion, a major doping technique that is still undetectable. Plasma miRNA levels were analyzed using high-throughput quantitative real-time PCR. Plasma samples were obtained before and at several time points after autologous blood transfusion (blood bag storage time 42 days) in 10 healthy subjects and 10 controls without transfusion. Other serum markers of erythropoiesis were determined in the same samples. Our results revealed a distinct change in the pattern of circulating miRNAs. Ten miRNAs were upregulated in transfusion samples compared with control samples. Among these, miR-30b, miR-30c, and miR-26b increased significantly and showed a 3.9-, 4.0-, and 3.0-fold change, respectively. The origin of these miRNAs was related to pulmonary and liver tissues. Erythropoietin (EPO) concentration decreased after blood reinfusion. A combination of miRNAs and EPO measurement in a mathematical model enhanced the efficiency of autologous transfusion detection through miRNA analysis. Therefore, our results lay the foundation for the development of miRNAs as novel blood-based biomarkers to detect autologous transfusion.     

Blood leukocyte responses to extracorporeal circulation. I. Short term extracorporeal circulation in dogs without and with extracorporeal irradiation

Short term (1 h) extracorporeal circulation without or with irradiation of blood was performed in two normal dogs in a series of experiments. The granulocyte count was constantly diminished, while the lymphocytes did not show any particular change in their concentration. In the majority of the experiments a decrease of the CFU-C content occurred to less than 70% of the initial level. There was no difference in the results of experiments with or without irradiation. In the "bag to bag" procedures, no significant change in the blood leukocyte counts including CFU-C, was established.     

Kinetics of neutrophil-releasing activity of filtration leukapheresis and postleukapheresis plasma

A rat model was used to study the effect of filtration leukapheresis on the kinetics of granulocyte mobilization in normal rat donors and in recipients of plasma obtained from these donors. Our earlier observations showed that infusion of postpheresis plasma (PPP) into normal homologous recipients is consistently capable of inducing a marked granulocytosis. The effects of such a transfusion is dose related and duration dependent. This study shows that the granulocytosis occurring subsequent to administration of PPP was directly related to the duration of pheresis in the donor. Its maximum effect occurred 2–3 hr after transfusion. Animals with a low granulocyte count were less capable of mobilizing granulocytes during filtration leukapheresis than animals with a higher prepheresis count, possibly due to low endogenous stores of granulopoietin. Additionally, rats < 300 g were capable of mobilizing fewer granulocytes per volume of circulating blood than were larger (older?) animals. The maximum ability of PPP to increase circulating granulocyte numbers was found when postpheresis plasma was injected along with concurrent removal of circulating granulocytes by filtration leukapheresis.     

CFU-C YIELDS FROM THE HAEMOPOIETIC TISSUES OF NORMAL AND LEUKAEMIC RFM MICE

Spleen and bone marrow cells from normal and leukaemic RFM mice have been assayed for numbers of colony forming cells in soft agar (CFU-C). The fluctuations in CFU-C yield observed during the development of myeloid leukaemia are similar to the results from in vitro experiments set up to test a model, and are not incompatible with the idea that interaction between normal and leukaemic cells may modify the yield of CFU-C under the present conditions of culture. Colonies grown from leukaemic spleen and bone marrow cells appear to be derived from the residual population of normal haemopoietic cells within the leukaemic mouse.     

Interferon is the suppressor of hematopoiesis generated by stimulated lymphocytes in vitro

Lymphocytes that inhibit hematopoiesis may have a pathogenic role in some forms of bone marrow failure, and lymphocyte-mediated suppression may also be important in the normal regulation of bone marrow function. We have investigated the mechanism of in vitro suppression of hematopoiesis by T cells by using the methylcellulose colony culture system. Total peripheral blood T cells and separated subpopulations of helper (OKT4+) and suppressor (OKT8+) cells that have been stimulated by exposure to lectin suppress autologous colony formation by bone marrow myeloid (CFU-C) and erythroid (BFU-E) progenitor cells. Medium conditioned by these cells is also inhibitory, indicating that the suppressor activity is a soluble factor. A strong correlation existed for the concentration of interferon and the degree of hematopoietic suppressor activity in these supernatants; both activities peaked at days 3 to 5 of incubation and had sharply declined by day 7. Interferon production was enhanced by exposure of lymphocytes to sheep red blood cells during the rosetting procedure. Specific antiserum and a monoclonal antibody directed against gamma-(immune) interferon abrogated the inhibitory activity for hematopoiesis produced by lectin-stimulated T cells; an antiserum to alpha-interferon was generally much less effective in neutralizing activity. We infer from these results that gamma-interferon is the mediator of hematopoietic suppression generated by lectin-treated T-cells.     

Merocyanine 540 as a fluorescent probe of membranes: selective staining of leukemic and immature hemopoietic cells.

We have reported (Easton, Valinsky and Reich, 1978) that merocyanine 540 (MC 540) specifically stains a variety of living excitable cells, but not nonexcitable cells. This paper describes the exceptional permeability to MC 540 of leukemic leukocytes and immature hemopoietic precursor cells. We have used fluorescence microscopy and uptake of radioactive dye to study MC 540 staining of peripheral blood leukocytes from 80 leukemic and 34 normal individuals; leukemic leukocytes stain, whereas normal leukcytes do not. The leukocyte staining reaction differs from that previously described for excitable cells since it is independent of the ionic composition of the staining medium, kinetically complex, enhanced by light, enhanced by oxygen and essentially irreversible. Virtually all circulating nucleated cells from leukemic individuals are stained to approximately the same extent, and there is no qualitative or quantitative distinction between the various forms of leukemia. We have also found that MC 540 interacts with granulopoietic colony-forming cells (CFU-C) and with spleen colony-forming cells derived from mouse bone marrow (CFU-S). We cannot as yet identify a specific property of leukocyte plasma membranes that determines MC 540 permeability; since changes in MC 540 uptake appear to be correlated with cellular maturation during normal hemopoiesis, the retention of staining by leukemic cells, some of which appear morphologically normal, may indicate of failure in membrane maturation during leukemic blood cell development.     

Red blood cell life span in the ovine fetus

Red cell life span within the fetal circulation has not been reported, although erythrocyte life span has been studied in the adult and newborn. The present study quantified red cell life span in 12 chronically catheterized fetal sheep at 97-136 days gestation (term = 150 days) with the use of autologous red cells labeled with [(14)C]cyanate. Cyanate forms a permanent covalent bond with hemoglobin and acts as a permanent red cell label. In the fetuses, blood (14)C activity decreased in a curvilinear fashion with time and reached 50% of the initial activity at 16.4 +/- 1.6 (SE) days. In contrast, (14)C activity of autologous red cells in two adult ewes decreased linearly with time as expected, reached 50% of the initial (14)C activity in 59 days, and yielded life spans of 117 and 121 days. Computer modeling and parameter optimization taking into account growth and skewed life span distribution were used to analyze the (14)C disappearance curve in each fetus. The mean life span of all red cells in the fetal circulation was 63.6 +/- 5.8 days. Mean red cell life span increased linearly from 35 to 107 days as fetal age increased from 97 to 136 days (r = 0.83, P < 0.001). Life span of cells produced at the time of labeling was significantly greater than the mean life span. Fetal growth rate estimated from parameter optimization was 3.28 +/- 0.72%/day; this compared well with the rate of 3.40 +/- 0.14%/day calculated from fetal weights at autopsy. Mean corpuscular volume decreased as a function of gestational age, but the decrease was small compared with the large increase in red cell life span. We conclude the following: 1) red cell life span in the fetal circulation is short compared with the adult; 2) red cells in younger fetuses have shorter life spans than in near-term fetuses; 3) the curvilinear disappearance of labeled red cells in the fetus appears to be due primarily to an expanding blood volume with fetal growth; and 4) red blood cell life span in a growing organism will be significantly underestimated unless the expansion of blood volume with growth is taken into account.