Rhinovirus-induced epithelial RIG-I inflammasome suppresses antiviral immunity and promotes inflammation in asthma and COVID-19

Rhinoviruses and allergens, such as house dust mite are major agents responsible for asthma exacerbations. The influence of pre-existing airway inflammation on the infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is largely unknown. We analyse mechanisms of response to viral infection in experimental in vivo rhinovirus infection in healthy controls and patients with asthma, and in in vitro experiments with house dust mite, rhinovirus and SARS-CoV-2 in human primary airway epithelium. Here, we show that rhinovirus infection in patients with asthma leads to an excessive RIG-I inflammasome activation, which diminishes its accessibility for type I/III interferon responses, leading to their early functional impairment, delayed resolution, prolonged viral clearance and unresolved inflammation in vitro and in vivo. Pre-exposure to house dust mite augments this phenomenon by inflammasome priming and auxiliary inhibition of early type I/III interferon responses. Prior infection with rhinovirus followed by SARS-CoV-2 infection augments RIG-I inflammasome activation and epithelial inflammation. Timely inhibition of the epithelial RIG-I inflammasome may lead to more efficient viral clearance and lower the burden of rhinovirus and SARS-CoV-2 infections.

Human Cortex Spheroid with a Functional Blood Brain Barrier for High-Throughput Neurotoxicity Screening and Disease Modeling

The integral selectivity characteristic of the blood brain barrier (BBB) limits therapeutic options for many neurologic diseases and disorders. Currently, very little is known about the mechanisms that govern the dynamic nature of the BBB. Recent reports have focused on the development and application of human brain organoids developed from neuro-progenitor cells. While these models provide an excellent platform to study the effects of disease and genetic aberrances on brain development, they may not model the microvasculature and BBB of the adult human cortex. To date, most in vitro BBB models utilize endothelial cells, pericytes and astrocytes. We report a 3D spheroid model of the BBB comprising all major cell types, including neurons, microglia and oligodendrocytes, to recapitulate more closely normal human brain tissue. Spheroids show expression of tight junctions, adherens junctions, adherens junction-associated proteins and cell specific markers. Functional assessment using MPTP, MPP+ and mercury chloride indicate charge selectivity through the barrier. Junctional protein distribution was altered under hypoxic conditions. Our spheroid model may have potential applications in drug discovery, disease modeling, neurotoxicity and cytotoxicity testing.

Assessment of oncolytic HSV efficacy following increased entry-receptor expression in malignant peripheral nerve sheath tumor cell lines

Limited expression and distribution of nectin-1, the major herpes simplex virus (HSV) type-1 entry-receptor, within tumors has been proposed as an impediment to oncolytic HSV (oHSV) therapy. To determine whether resistance to oHSVs in malignant peripheral nerve sheath tumors (MPNSTs) was explained by this hypothesis, nectin-1 expression and oHSV viral yields were assessed in a panel of MPNST cell lines using γ134.5-attenuated (Δγ134.5) oHSVs and a γ134.5 wild-type (wt) virus for comparison. Although there was a correlation between nectin-1 levels and viral yields with the wt virus (R=0.75, P =0.03), there was no correlation for Δγ134.5 viruses (G207, R7020 or C101) and a modest trend for the second-generation oHSV C134 (R=0.62, P=0.10). Nectin-1 overexpression in resistant MPNST cell lines did not improve Δγ134.5 oHSV output. While multistep replication assays showed that nectin-1 overexpression improved Δγ134.5 oHSV cell-to-cell spread, it did not confer a sensitive phenotype to resistant cells. Finally, oHSV yields were not improved with increased nectin-1 in vivo. We conclude that nectin-1 expression is not the primary obstacle of productive infection for Δγ134.5 oHSVs in MPNST cell lines. In contrast, viruses that are competent in their ability to counter the antiviral response may derive benefit with higher nectin-1 expression.

Systematic review: outpatient management of acute uncomplicated diverticulitis

PURPOSE OF REVIEW

Acute uncomplicated diverticulitis is traditionally managed by inpatient admission for bowel rest, intravenous fluids and intravenous antibiotics. In recent years, an increasing number of publications have sought to determine whether care might instead be conducted in the community, with earlier enteral feeding and oral antibiotics. This systematic review evaluates the safety and efficacy of such an ambulatory approach.

METHODS

Medline, Embase and Cochrane Library databases were searched. All peer-reviewed studies that investigated the role of ambulatory treatment protocols for acute uncomplicated diverticulitis, either directly or indirectly, were eligible for inclusion.

RESULTS

Nine studies were identified as being suitable for inclusion, including one randomised controlled trial, seven prospective cohort studies and one retrospective cohort study. All, except one, employed imaging as part of their diagnostic criteria. There was inconsistency between studies with regards to whether patients with significant co-morbidities were eligible for ambulatory care and whether bowel rest therapy was employed. Neither of these variables influenced outcome. Across all studies, 403 out of a total of 415 (97 %) participants were successfully treated for an episode of acute uncomplicated diverticulitis using an outpatient-type approach. Cost savings ranged from 35.0 to 83.0 %.

CONCLUSION

Current evidence suggests that a more progressive, ambulatory-based approach to the majority of cases of acute uncomplicated diverticulitis is justified. Based on this evidence, the authors present a possible outpatient-based treatment algorithm. An appropriately powered randomised controlled trial is now required to determine its safety and efficacy compared to traditional inpatient management.

Human blood and marrow side population stem cell and Stro-1 positive bone marrow stromal cell numbers decline with age, with an increase in quality of surviving stem cells: correlation with cytokines

Hematological deficiencies increase with aging leading to anemias, reduced hematopoietic stress responses and myelodysplasias. This study tested the hypothesis that side population hematopoietic stem cells (SP-HSC) would decrease with aging, correlating with IGF-1 and IL-6 levels and increases in bone marrow fat. Marrow was obtained from the femoral head and trochanteric region of the femur at surgery for total hip replacement (N=100). Whole trabecular marrow samples were ground in a sterile mortar and pestle and cellularity and fat content determined. Marrow and blood mononuclear cells were stained with Hoechst dye and the SP-HSC profiles acquired. Marrow stromal cells (MSC) were enumerated flow cytometrically employing the Stro-1 antibody, and clonally in the colony forming unit fibroblast (CFU-F) assay. Plasma levels of IGF-1 (ng/ml) and IL-6 (pg/ml) were measured by ELISA. SP-HSC in blood and bone marrow decreased with age but the quality of the surviving stem cells increased. MSC decreased non-significantly. IGF-1 levels (mean=30.7, SEM=2) decreased and IL-6 levels (mean=4.4, SEM=1) increased with age as did marrow fat (mean=1.2mmfat/g, SEM=0.04). There were no significant correlations between cytokine levels or fat and SP-HSC numbers. Stem cells appear to be progressively lost with aging and only the highest quality stem cells survive.

Enteroviruses, type 1 diabetes and hygiene: a complex relationship

Type 1 diabetes (T1D) is an autoimmune disease in which the immune system mounts an attack on the host's insulin‐producing β cells. Because most cases of T1D cannot be attributed only to individual genetics, it is strongly inferred that there is a significant environmental contribution, such as infection, impacting disease development. The human enteroviruses (HEV) are common picornaviruses often implicated as triggers of human T1D, although precisely which of the numerous HEV may be involved in human T1D development is unknown. Experiments using non‐obese diabetic (NOD) mice, commonly used to model T1D, show that induction of T1D by HEV infection in NOD mice is a multifactorial process involving both the virus and the host. Interestingly, results demonstrate that HEV infection of NOD mice can also induce long‐term protection from T1D under certain conditions, suggesting that a similar mechanism may occur in humans. Based upon both experimental animal and observational human studies, we postulate that HEV have a dual role in T1D development and can either cause or prevent autoimmune disease. Whichever outcome occurs depends upon multiple variables in the host‐virus equation, many of which can be deduced from results obtained from NOD mouse studies. We propose that the background to the sharply rising T1D incidences observed in the 20th century correlates with increased levels of hygiene in human societies. Viewing T1D in this perspective suggests that potential preventative options could be developed. Copyright © 2009 John Wiley & Sons, Ltd.

An ex vivo model of hematopoietic stem cell mobilization

BACKGROUND

Mobilization of hematopoietic stem cells to the circulation facilitates their collection, thereby providing a non-marrow source of these cells for transplantation. Hematopoietic cytokine administration induces mobilization for most, but not all, donors. Because the underlying biology of mobilization is not well understood, improving the process on a rational basis is difficult. The design of an in vitro mobilization model was pursued to facilitate investigations of the process.

METHODS

MS5 murine stromal cell line cells were grown to confluence on microporous transwell membranes. Murine femoral marrow plugs were placed on top of the prepared transwell membranes. The transwells were then seated in wells containing media and hematopoietic growth factors. Cells that were released from the marrow plugs over time and migrated through the stromal layer into the wells were assayed for stem cell/progenitor cell characteristics.

RESULTS

Few or no GM-CSF (progenitors) were found in wells containing media alone or media plus mobilizing cytokines after 24 h. After 120 h, the numbers of cells in the cytokine-containing wells increased, as did the numbers of CD34(+) cells. Cells in the wells at the time progenitor cells were most frequent were shown to include side population (SP) hematopoietic stem cells. After 120 h in the presence of cytokines, cells pooled from the wells were transplanted to lethally irradiated mice. Eighty per cent of the transplanted mice survived 30 days or more, demonstrating that radioprotective stem cells were present in the wells.

DISCUSSION

An ex vivo model has been designed that may aid investigations of the various steps of stem cell mobilization.

Immunological properties of mononuclear cells from blood stem cell harvests following mobilization with erythropoietin + G-CSF in cancer patients

BACKGROUND

Although the recombinant granulocyte colony-stimulating factor (G-CSF) is a good CD34 cell mobilizer, the effects of G-CSF mobilization on the immune effector function of the individual is not always optimal. We studied the functional and phenotypic properties of peripheral blood stem cells (PBSC) collected from 15 cancer patients mobilized with G-CSF plus recombinant erythropoietin (EPO).

METHODS

The patients received EPO (300 U/kg) and (G-CSF 1 microg/kg) per day as mobilizing cytokines and an autologous graft product was collected with at least daily apheresis procedures until a target number of CD34 cells and mononuclear cells were obtained. Mononuclear cells from the first four PBSC collections were tested for their natural killer (NK), activated NK and lymphokine activated killer (LAK) cytotoxicity in vitro against K562 and Raji tumor target cells.

RESULTS

There was a significant increase in NK, activated NK and LAK cytotoxicity in EPO + G-CSF mobilized cells when compared to mononuclear cells from premobilization blood baseline values. Although there was no increase in CD3+ T cells, there was a significant increase in myeloid cells (CD14+), B-cells (CD20+) and NK cells (CD56+) following mobilization. There was no difference in T cell response to the mitogens PHA and Con-A, but there was an increase in B-cell response to PWM following mobilization. Thus, the combination of EPO + G-CSF not only mobilized hematopoietic precursor cells but also increased the number of immune effector cells in the PBSC collections.

An integrated process for measuring the physicochemical properties of drug candidates in a preclinical discovery environment

Automated log P, pK(a), solubility, and chemical stability systems comprise an integrated process that provides early stage physicochemical property data to the discovery research organization. Capillary electrophoresis (CE) techniques are used to experimentally determine pK(a) and log P. Solubility is determined using a quasi-equilibrium approach employing sample quantitation by flow injection analysis with ultraviolet (UV) detection at 256 nm. Chemical stability is assessed by challenging compounds with pH 2, pH 7, pH 12, and 3% hydrogen peroxide solutions overnight, and comparing the chromatographic profiles of the stability challenged solutions to that of a freshly prepared control. Validation of the log P method using a set of drug-like compounds demonstrates that the method yields log P values within +/-0.5 units of literature values. The log P method is valid over the range -0.5-5.0, and the technique is compatible with acidic, neutral, and basic compounds. The pK(a) technique yields results within +/-0.2 units of corresponding values obtained by potentiometric titration over a pK(a) range of 2 to 12. Solubility is reported in a 3-60 microg/mL range, and the results are generally within 20% of values measured by equilibrium solubility techniques. The current level of automation supports the measurement of the physicochemical properties of 100 compounds per week. Physicochemical property data for approximately 2000 compounds have been generated to date.

Oligonucleotide enhanced cytotoxicity of Idarubicin for lymphoma cells

Oligonucleotides offer the potential to manipulate gene expression in targeted cells which might be exploitable for therapeutic benefit. The effects of combining a phosphorothioate oligonucleotide OL(1) p53, which transiently down-regulates p53 levels, with an anthracycline, Idarubicin, on the growth of wild-type p53 WMN gene-expressing lymphoma cells was evaluated. Fluorescent OL(1) p53, was used to demonstrate oligonucleotide uptake and retention by the WMN cells. Uptake was maximal at 24 hours and compared to baseline (0 hours) increasing apoptotic cells were evident in WMN cells treated with OL(1) (1 microM) alone and in combination with Idarubicin (0.2 nM) for 24 to 48 hours. In cells treated with OL(1) p53 and Idarubicin, truncated p53 message of a predicted 201 base pair length based on RNAase H cleavage of the OL(1) p53-p53 mRNA heteroduplex was detected after 7 hours of incubation. The message for p53 was transiently downregulated as detected by RT-PCR analysis at 24 hours, and protein levels transiently reduced at 36 hours, as shown by a quantitative Western blot. Corresponding to these events, the growth of WMN cells ceased after 48 hours in the concurrent presence of OL(1) p53 and Idarubicin and, the lymphoma cells were dead after 72 hours. No reduction in hematopoietic colony forming cell capacity of similarly treated hematopoietic progenitor cells harvested from cytokine-mobilized blood by apheresis was observed. Therefore, synergistic cytotoxicity of Idarubicin for lymphoma cells treated with an oligonucleotide targeting p53 message was demonstrated at oligonucleotide and Idarubicin concentrations which were minimally toxic to hematopoietic progenitor cells. This approach offers new opportunities for purging of lymphoma cells from hematopoietic harvests and systemic lymphoma therapy.

Circulating factors may be responsible for murine strain-specific responses to mobilizing cytokines

OBJECTIVE

To determine if circulating factors influence strain-specific responses to administration of hematopoietic stem-cell mobilizing cytokines, a murine model was employed.

METHODS

Plasma aliquots from intact DBA2, Balb/c, and C57Bl/6 mice were injected into intact Balb/c mice prior to delivery of mobilizing cytokines. Control Balb/c mice were injected with mobilizing cytokines alone. Plasma from hemi-body irradiated Balb/c mice, known to inhibit mobilization, was also injected into Balb/c mice. Twenty-four hours later, spleen cells were harvested and assayed for granulocyte-macrophage colony-forming cells (GM-CFC) and high-proliferative-potential colony-forming cells (HPP-CFC). Simultaneously harvested blood aliquots were assayed for CD45(+)/CD34(+) cells using flow cytometric techniques.

RESULTS

Mice receiving plasma from any source demonstrated significant inhibition of mobilization of HPP-CFC and GM-CFC to the spleen as compared to mobilized controls; for HPP-CFC, plasma from C57Bl/6 mice was more inhibitory than plasma from Balb/c (p = 0.001) or from DBA2 mice (p = 0.01), while for GM-CFC, plasma from C57Bl/6 mice was more inhibitory than Balb/c plasma but not more inhibitory than DBA2 plasma. Mice injected with plasma from previously irradiated Balb/c mice exhibited the expected HPP-CFC and GM-CFC mobilization inhibition, which was not statistically different from the inhibition seen in animals that received C57Bl/6 plasma. Mobilization of CD34(+)/CD45(+) cells to the blood also appeared to be inhibited by pretreatment with C57Bl/6 plasma, but not DBA2 plasma.

CONCLUSION

These data suggest that strain-specific patterns of mobilization may be influenced by a circulating mobilization inhibitor(s).

Feasibility of interspecies extrapolation in determining the bioequivalence of animal products intended for intramuscular administration

To examine the validity of extrapolating parenteral product bioequivalence determinations across target animal species, the relative bioavailability of two injectable formulations of ampicillin trihydrate (PolyflexR, a water-based suspension, and Ampi-kel 10R, an oil-based suspension) was examined in calves, sheep and swine. Employing products recognized to be bioinequivalent provided an opportunity to explore potential species-by-formulation interactions. As compared with PolyflexR, Ampi-kel 10R exhibited lower area under the curve (AUC) estimates but higher peak concentrations in all target animal species. Nevertheless, marked interspecies differences were noted in the width and bounds of the confidence intervals about the differences in treatment means. Potential physiological and physico-chemical reasons for these findings are discussed.

Histone H2A.Z has a conserved function that is distinct from that of the major H2A sequence variants

Saccharomyces cerevisiae contains three genes that encode members of the histone H2A gene family. The last of these to be discovered, HTZ1 (also known as HTA3), encodes a member of the highly conserved H2A.Z class of histones. Little is known about how its in vivo function compares with that of the better studied genes (HTA1 and HTA2) encoding the two major H2As. We show here that, while the HTZ1 gene encoding H2A.Z is not essential in budding yeast, its disruption results in slow growth and formamide sensitivity. Using plasmid shuffle experiments, we show that the major H2A genes cannot provide the function of HTZ1 and the HTZ1 gene cannot provide the essential function of the genes encoding the major H2As. We also demonstrate for the first time that H2A.Z genes are functionally conserved by showing that the gene encoding the H2A.Z variant of the ciliated protozoan TETRAHYMENA: thermophila is able to rescue the phenotypes associated with disruption of the yeast HTZ1 gene. Thus, the functions of H2A.Z are distinct from those of the major H2As and are highly conserved.

Activity of acetyl-Ser-Asp-Lys-Pro (AcSDKP) on human hematopoietic progenitor cells in short-term and long-term bone marrow cultures

The tetrapeptide acetyl-Ser-Asp-Lys-Pro (AcSDKP) is a potent inhibitor of hematopoietic stem cell proliferation. We examined the effects of AcSDKP on the production of granulocyte-macrophage colony-forming cells (CFU-GM) and high proliferative potential colony-forming cells (HPP-CFC) in human long-term bone marrow (LTBM) cultures and CFU-GM and erythroid burst-forming cells (BFU-e) in short-term liquid cultures. The addition of AcSDKP in short-term bone marrow cultures resulted in a maximum depression of the total number of progenitor cells as well as the number of progenitor cells entering cell cycle following culture with 10(-12) to 10(-14) M AcSDKP and 10(-14) M AcSDKP when exogenous cytokines (GM-CSF, IL-3, or SCF) were added. AcSDKP was added daily to LTBM cultures at various concentrations (10(-8) M to 10(-16) M) for up to 5 weeks. In these LTBM culture studies, AcSDKP inhibited the entry of nonadherent progenitor cells into S phase and decreased the number of nonadherent progenitor cells with peak activity at 10(-12) M. In contrast, AcSDKP had no effect on the number of adherent CFU-GM, HPP-CFC, or cellularity per culture or percent of adherent progenitor cells in S phase. These studies indicate that the concentration of the tetrapeptide is critical to the activity of AcSDKP on human hematopoietic progenitor cells. Furthermore, we report that the presence of cytokines or stromal cells also affects the response of progenitor cells to AcSDKP. These results will aid in determining kinetic properties of AcSDKP for the development of clinical protocols to protect normal human hematopoietic stem and progenitor cells following cycle-specific chemotherapy agents.

Pharmacokinetics and in vivo effects of a six-base phosphorothioate oligodeoxynucleotide with anticancer and hematopoietic activities in swine

A short phosphorothioate oligodeoxynucleotide telomere mimic with the sequence 5'-d(TTAGGG)-3', TAG-6, has been shown to inhibit telomerase activity and have antineoplastic and hematopoietic stimulatory properties. In this study, three immature male domestic swine (weighing approximately 40 kg) were administered 200 mg/m2 of TAG-6 by continuous intravascular infusion at rates of 0.48 +/- 0.07 mg/hr for 14 days to evaluate the pharmacokinetics, toxicity, and tissue distribution. There was considerable variability (both within each animal and across animals) observed in the pharmacokinetic data. The plasma half-life (t1/2 appeared to be short enough that it could be assumed that steady state was attained by at least 96 h after the start of the infusion. The t1/2 estimates for the three pigs were 8.96, 109, and 1.97 h (the long t1/2 for pig 2 may be explained by poor parameter estimation due to the variability). The volume of distribution ranged from 9.80 to 51.8 L (0.3-1.4 L/kg), and plasma clearance estimates ranged from 0.33 to 3.46 L/h (5.5-57.7 ml/min). The average plasma concentrations at steady state were 0.845, 0.933, and 0.178 microg/ml (0.44, 0.49, and 0.093 microM) for the three animals. Nearly 30% of the administered dose was cleared through renal excretion by day 7 postinfusion. The distribution of TAG-6 was primarily to the liver and kidney, but the spleen and thyroid accumulated relatively high concentrations of TAG-6. TAG-6 was metabolized to apparently higher molecular weight products, which were observed in the urine. The size periodicity of these apparently higher molecular weight products was in 6-base intervals, which is consistent with the actions of telomerase. The infusion did not produce significant changes in serum chemistry or circulating blood cells, but a decrease in colony-forming unit-granulocyte-monocyte (CFU-GM) colony formation from BM was observed. These data suggest that TAG-6 may be a very specific pharmacophore.

Unmet needs in hypertension: challenges and opportunities

On the verge of the new millennium, hypertension remains an area of significant unmet medical need. Although progress has been made in the awareness, treatment, and control of hypertension during the last half of the 20th century, recent trends suggest that progress has stalled. Unfavorable trends in awareness and control have been noted by researchers at the Mayo Clinic, in a community that is socioeconomically prosperous with easy access to primary and tertiary medical care. Evidence suggests that a renewed focus on systolic blood pressure and on efforts to maintain compliance will result in better outcomes in populations at risk. Hiatt and Goldman have presented the case for "making medicine more scientific"--that is, understanding how the application of medical care advances can best be applied to benefit population health status. This is the challenge that hypertension control presents in world populations. Aging societies make this challenge an urgent concern.

Persistence with treatment for hypertension in actual practice

BACKGROUND

Despite the existence of efficacious medications, many patients in actual practice remain with uncontrolled hypertension. Randomized clinical trials, cannot address this issue well given their highly restricted environment. This paper examines persistence with antihypertensive therapy among patients in actual practice.

METHODS

Cohort study of patients who received a diagnosis of hypertension and were treated between 1989 and 1994 identified through the Saskatchewan Health databases. Patients with concurrent diagnoses likely to affect initial treatment choice were excluded. The resulting population of 79,591 subjects was grouped into those with established hypertension (52,227 [66%]) and those with newly diagnosed hypertension (27,364 [34%]). The initial antihypertensive prescription, subsequent changes in treatment and persistence with antihypertensive therapy were analysed.

RESULTS

Persistence with antihypertensive therapy decreased in the first 6 months after treatment was started and continued to decline over the next 4 years. Of the patients with newly diagnosed hypertension, only 78% persisted with therapy at the end of 1 year, as compared with 97% of the patients with established hypertension (p < 0.001). Among those with newly diagnosed hypertension, older patients were more likely than younger ones to persist, and women were more likely than men to persist (p < 0.001).

INTERPRETATION

This analysis of actual practice data indicates that barriers to persistence occur early in the therapeutic course and that achieving successful therapy when treatment is started is important to maintaining long-term persistence.

Effect of initial drug choice on persistence with antihypertensive therapy: the importance of actual practice data

BACKGROUND

Rational medical decisions should be based on the best possible evidence. Clinical trial results, however, may not reflect conditions in actual practice. In hypertension, for example, trials indicate equivalent antihypertensive efficacy and safety for many medications, yet blood pressure frequently remains uncontrolled, perhaps owing to poor compliance. This paper examines the effect of initial choice of treatment on persistence with therapy in actual practice.

METHODS

The authors examined all outpatient prescriptions for antihypertensive medications filled in Saskatchewan between 1989 and 1994 by over 22,000 patients with newly diagnosed hypertension whose initial treatment was with a diuretic, beta-blocker, calcium-channel blocker or angiotensin-converting-enzyme (ACE) inhibitor. Rates of persistence over the first year of treatment were compared.

RESULTS

After 6 months, persistence with therapy was poor and differed according to the class of initial therapeutic agent: 80% for diuretics, 85% for beta-blockers, 86% for calcium-channel blockers and 89% for ACE inhibitors (p < 0.001). These differences remained significant when age, sex and health status in the previous year were controlled for. Changes in the therapeutic regimen were also associated with lack of persistence.

INTERPRETATION

A relation not seen in clinical trials--between persistence with treatment and initial antihypertensive medication prescribed--was found in actual practice. This relation also indicates the importance of real-world studies for evidence-based medicine.

Cell cycle-based purging of lymphoma cells from bone marrow harvests using radioiodinated 5-iodo-2'-deoxyuridine

Minimal residual disease in lymphoma patients is a major problem in the clinical management of their cancer. High-dose chemotherapy followed by autologous bone marrow transplantation has been used to treat the disease. However, residual lymphoma may be reintroduced along with the marrow if it is present in the bone marrow harvest. In this report we describe results of experiments testing the efficacy of 5-[125I]-iodo-2'-deoxyuridine (125IdU) for purging murine RAW117 large cell lymphoma cells (Joshi et al., Oncology 44, 180-185, 1987; Cancer Res. 47, 3551-3557, 1987) from bone marrow in a relevant animal model. Donor BALB/c mice were injected with murine RAW117 cells and euthanized on day 13, and their bone marrow that had been contaminated with tumor cells was harvested and treated in vitro with 125IdU or nonradioactive 127IdU (control). Nine of 10 mice receiving 127IdU-treated bone marrow contaminated with tumor cells died at an average of 17 days after injection. In comparison, 9 of 10 mice injected with 125IdU-treated bone marrow contaminated with tumor cells were still alive after 82 days. In addition, the 125IdU treatment did not diminish the formation of hematopoietic progenitor cell colonies in normal mouse and human peripheral blood stem cells.

Cell adhesion molecule expression on CD34+ cells in grafts and time to myeloid and platelet recovery after autologous stem cell transplantation

The relationship between cell adhesion receptor expression on CD34+ cells in stem cell grafts and the time to neutrophil and platelet recovery after autologous stem cell transplantation (ASCT [n = 25]) was studied with granulocyte/monocyte-colony stimulating factor (GM-CSF)-mobilized peripheral blood stem cells (PBSCs) and steady-state bone marrow (BM) harvests. Cell adhesion receptor expression was analyzed using flow cytometry after CD34+ cell enrichment. Significantly higher expression of L-selectin and CD44, and significantly lower expression of VLA-4, LFA-1, ICAM-1, Sialyl Lewis(x), Sialyl Lewis(A), and Thy-1 were observed on PBSCs compared with BM CD34+ cells. The log of the number of reinfused CD34+ cells, colony forming units granulocyte/macrophage (CFU-GM), and CD34+ cells coexpressing VLA-4, VLA-5, LAF-1, Mac-1, LFA-3, or CD38 but not ICAM-1, Sialyl Lewis(x), Sialyl Lewis(A), or Thy-1 correlated with the time required to reach an absolute neutrophil count (ANC) of > or =0.5 x 10(9)/L. In addition, the log of the number of CD34+ L-selectin+ and CD34+CD44+ cells reinfused after ASCT correlated better with the time required to reach an ANC of > or =0.5 x 10(9)/L than did the log of the number of CD34+ cells or CFU-GM reinfused. The log of the number of reinfused CD34+ cells, CFU-GM, and CD34+ cells coexpressing CD44, L-selectin, VLA-5 Mac-1, or CD38, but not VLA-4, LAF-1, ICAM-1, LAF-3, Sialyl Lewis(X), Sialyl Lewis(A), or Thy-1, correlated with the time required to reach a platelet count of >20 x 10(9)/L. Thus, L-selectin or CD44 may play an important role in the homing of progenitors after ASCT. In addition, the higher proportion of CD34+L-selectin+ or CD34+CD44+ cells in leukapheresis products may provide one explanation for the more rapid hematologic reconstitution observed after PBSC transplantation.

Ex vivo treatment of bone marrow with phosphorothioate oligonucleotide OL(1)p53 for autologous transplantation in acute myelogenous leukemia and myelodysplastic syndrome

Effective ex vivo purging techniques can decrease the likelihood of infusing bone marrow contaminated with leukemic cells during autologous transplantation. In preliminary studies, OL(1)p53, a 20-mer phosphorothioate oligonucleotide directed against p53 mRNA, decreased the number of acute myelogenous leukemia (AML) cells in vitro, suggesting a possible role for OL(1)p53 in purging bone marrow harvests of leukemia cells. To demonstrate that OL(1)p53 was nontoxic to hematopoietic progenitor cells, normal bone marrow cells were incubated with 10 microM OL(1)p53 for 36 h, and hematopoietic progenitor cell survival was determined by in vitro colony assays. OL(1)p53 had no toxic effect on the growth of either myeloid (CFU-GM) or erythroid (BFU-E) progenitor cells. OL(1)p53 was then used to ex vivo purge bone marrow harvests from nine patients with either AML or myelodysplastic syndrome (MDS). Bone marrow cells were incubated with 10 microM OL(1)p53 for 36 h before transplantation. The median times posttransplantation for the patient to recover an absolute neutrophil count greater than 0.5 x 10(9)/L and a platelet transfusion independence were 30 days and 56 days, respectively. Incubation of bone marrow cells with OL(1)p53 had no detrimental effect on the growth of hematopoietic progenitor cells, and transplantation of autologous bone marrow cells treated with the phosphorothioate oligonucleotide, OL(1)p53, resulted in successful recovery of circulating neutrophils following high-dose therapy in patients with AML or MDS. The data show that OL(1)p53 can be used safely to purge autologous bone marrow harvests from patients with leukemia.

A hexameric phosphorothioate oligonucleotide telomerase inhibitor arrests growth of Burkitt's lymphoma cells in vitro and in vivo

A phosphorothioate oligonucleotide (PS-ODN) with sequence identical to the repeat sequence of the mammalian telomere, 5'-d(TTAGGG)-3', was incubated with a Burkitt's lymphoma-derived (OMA-BL1) cell line. This hexanucleotide inhibits telomerase activity in cell lysates, lengthens cell doubling time, and induces apoptosis. Concatenated repeats (12-, 18-, and 24-mers) of the 5'-d(TTAGGG)-3' motif induce similar cellular responses. Scrambled sequences do not efficiently inhibit telomerase activity or significantly alter cell growth and viability. The in vivo efficacy of this PS-ODN was evaluated in a xenograft human-nude mouse model. Once tumors were established these animals were administered the telomere mimic, 5'-d(TTAGGG)-3', a control scrambled sequence 5'-d(TGTGAG)-3', or saline for 14 days via a subcutaneous osmotic pumps in a blinded study monitoring tumor size with dose and time. A significant decrease in tumor size was observed in animals given 50 micrograms/mouse/day 5'-d(TTAGGG)-3', but not following 5'-d(TGTGAG)-3', relative to the saline-treated animals. The antitumor activity of the 6-mer telomere mimic demonstrated a dose dependency including a reduction in metastatic nodules in the spleen. No activity was observed with the scrambled controls. In addition to antitumor activity we observed an increase in the mouse hematopoietic progenitor cell populations, BFU-e and CFU-GM. These results demonstrated the effects of a short hexameric oligonucleotide telomere mimic in vitro and in vivo and the potential utility of short oligonucleotides as telomerase inhibitors.

Allogeneic-blood stem-cell collection following mobilization with low-dose granulocyte colony-stimulating factor

PURPOSE

The optimal dose of granulocyte colony-stimulating factor (G-CSF) for mobilization of allogeneic-blood stem cells (AlloBSC) has yet to be determined. As part of a prospective trial, 41 related human leukocyte antigen (HLA)-matched donors had blood cells mobilized with G-CSF at 5 micrograms/kg/d by subcutaneous administration. The purpose of this trial was to monitor adverse effects during G-CSF administration and stem-cell collection, to determine the optimal timing for stem-cell collection, and to determine the cellular composition of stem-cell products following G-CSF administration.

PATIENTS AND METHODS

The median donor age was 42 years. Apheresis began on day 4 of G-CSF administration. At least three daily 12-L apheresis collections were performed on each donor. A minimum of 1.0 x 10(6) CD34+ cells/kg (recipient weight) and 8.0 x 10(8) mononuclear cells/kg were collected from each donor. All collections were cryopreserved in 5% dimethyl sulfoxide and 6% hydroxyethyl starch.

RESULTS

Toxicities associated with G-CSF administration and the apheresis process included myalgias/arthralgias (83%), headache (44%), fever (27%), and chills (22%). The median baseline platelet count of 242 x 10(4)/ mL decreased to 221, 155, and 119 x 10(6)/mL on days 4, 5, and 6 of G-CSF administration, respectively. Median numbers of CD34+ cells in collections 1, 2, and 3 were 1.99, 2.52, and 3.13 x 10(6)/kg, respectively. The percentage and total number of CD4+, CD8+, and CD56+/CD3- cells remained relatively constant during the three collections. Median total numbers of cells were as follows: CD34+, 7.73 x 10(6)/kg; and lymphocytes, 6.93 x 10(8)/kg.

CONCLUSION

Relatively low doses of G-CSF can mobilize sufficient numbers of AlloBSC safely and efficiently.

Hematopoietic recovery after allogeneic blood stem-cell transplantation compared with bone marrow transplantation in patients with hematologic malignancies

PURPOSE

To compare hematopoietic recovery, duration of hospitalization, and 100-day survival in patients who received allogeneic-blood stem cells (BSC) or conventional allogeneic bone marrow transplantation (BMT).

PATIENTS AND METHODS

From December 1994 to August 1995, 21 patients participated in a phase II study of allogeneic BSC transplantation. Cells mobilized with granulocyte colony-stimulating factor (G-CSF; 5 micrograms/kg/ d) were collected from human leukocyte antigen (HLA)-matched related donors and cryopreserved. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate. G-CSF (10 micrograms/kg/d) was administered posttransplant. The outcomes were compared with 22 identically treated historical patients who received allogeneic BMT.

RESULTS

The median infused CD34+ cell and granulocyte-macrophage colony-forming unit (CFU-GM) content were 7.73 x 10(4)/kg and 41.6 x 10(4)/kg, respectively. The median time to a neutrophil count greater than 500/ microL was 11 days after BSC and 16.5 days after BMT (P = .0003). A trend toward faster platelet and RBC recovery after BSC was observed. BSC patients received fewer platelet transfusions: 10 versus 19 (P = .015). The median length of hospitalization was shorter after BSC transplantation: 25 versus 31.5 days (P = .0243). The 100-day survival rates were similar: 83% after BSC and 75% after BMT (P = .3585). The incidence of acute GVHD grade II to IV was 57% and 45% for BSC and BMT, respectively (P = .4654).

CONCLUSION

In comparison to BMT, allogeneic BSC transplantation may result in faster hematopoietic recovery, shorter hospital stay, and similar early survival. Whether allogeneic BSC are superior to bone marrow needs to be determined in randomized trials.

Sequences within and flanking hypersensitive sites 3 and 2 of the beta-globin locus control region required for synergistic versus additive interaction with the epsilon-globin gene promoter

The locus control region is required for high-level, position-independent expression of mammalian beta-globin genes. It is marked by five major DNase hypersensitive sites (HSs) in a 16 kb region of chromatin, and the protein-DNA complexes that form these HSs may interact in a holocomplex that carries out the full function of the locus control region. Previous studies showed that a large rabbit DNA fragment containing both HS2 and HS3 in their native sequence context and spacing produced a much larger increase in expression of a linked reporter gene than the sum of the largest effects observed with DNA fragments containing HS2 or HS3 individually. To test whether this reflected a synergistic interaction between the 200-400 bp cores of the HSs or if this effect required additional sequences outside the cores, combinations of different restriction fragments containing HS2 or HS3 were tested for their ability to increase the expression of a hybrid epsilon-globin-luciferase reporter gene in transfected K562 cells. The results show that the human HS2 and HS3 cores do not interact either additively or synergistically with the reporter gene when juxtaposed, and separation by spacer DNA has little effect on their function. Fragments of human DNA containing cores plus flanking sequences for HS3 or HS2 show an additive effect in combination, whereas homologous fragments of rabbit DNA containing HS3 and HS2 interact synergistically. At least part of this difference localizes to the rabbit DNA fragment containing HS3, which can interact synergistically with the human DNA fragment containing HS2. The region 5' to the HS3 core plays a role both in the cooperative interaction observed with the rabbit DNA fragment and the domain-opening observed with the human DNA. A minor DNase HS maps to this region, and the pattern of sequence conservation is consistent with some difference in function between species.

Use of gene therapy to suppress the antigen-specific immune responses in mice to an HLA antigen

Hematopoietic chimerism has been used in the laboratory to induce life-long immunologic tolerance to donor antigens. The present study demonstrates that mice transplanted with autologous bone marrow cells retrovirally transduced to express HLA-A2.1 develop a significantly depressed immune response to this antigen while retaining normal reactivity to HLA-B7. Retrovirus-mediated transduction was performed using whole bone marrow-producer cell coculture. This approach did not result in significant gene transfer into hematopoietic progenitor cells. Despite this, the antibody response to HLA-A2.1 in mice reconstituted with genetically modified BMC was completely suppressed three months following bone marrow transplantation. Cell-mediated immunity to HLA-A2.1 was partially suppressed in three-fourths of animals tested three months later, although one animal had a CTL profile similar to that an of HLA-A2.1 transgenic mouse. Complete suppression of the antibody-mediated immune response occurred when only one-third of mice had evidence of the introduced genes in their spleen and one-tenth had the introduced sequences in their circulating WBCs by PCR. In conclusion, engineering of BMC to express donor MHC genes may be an alternative to xenogeneic BMT to induce chimerism and tolerance. More efficient transduction of bone marrow progenitor cells may result in more persistent gene expression and long-lasting transplantation tolerance in recipients of genetically modified bone marrow. Successful application of this technology may also be useful in altering immune responses to other external and self antigens.

Phase I trial of recombinant fusion protein PIXY321 for mobilization of peripheral-blood cells

PURPOSE

Mobilization of peripheral-blood cells (PBC) with cytokines alone results in rapid hematopoietic recovery and avoids the potential morbidity associated with mobilization by chemotherapy. PIXY321, a fusion protein that consists of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), has enhanced hematopoietic colony-forming activity as compared with individual or equimolar combinations of the two cytokines. A phase I trial of PIXY321 for mobilization of PBC in patients with malignant lymphoma was performed.

PATIENTS AND METHODS

Thirteen patients with malignant lymphoma who were eligible for high-dose therapy (HDT) were enrolled onto the trial. All patients were ineligible for autologous bone marrow transplantation due to overt metastatic disease in the marrow or to severe marrow hypocellularity. PIXY321 was administered at three dose levels of 250, 500, and 750 micrograms/m2/d by continuous infusion until completion of PBC collections. Collections were initiated when the WBC count was greater than 10 x 10(9)/L or 4 days after the initiation of PIXY321, whichever came first. Collections were continued until a minimum of 6.5 x 10(8) mononuclear cells (MNC)/kg patient weight were obtained.

RESULTS

PIXY321 was generally well tolerated. Side effects associated with PIXY321 administration did not exceed grade 2 and included fever (85%), chills/sweats (54%), myalgias (38%), fatigue (31%), nausea/vomiting (31%), headache (31%), edema (23%), and rhinorrhea (23%). The median numbers of colony-forming units-granulocyte/macrophage (CFU-GM) in the graft products for the three dose levels were 0.31, 2.94, and 2.88 x 10(4)/kg, respectively; the median numbers of burst-forming units-erythroid (BFU-e) were 0.20, 6.94, and 12.78 x 10(4)/kg, and the median numbers of CD34+ cells were 2.30, 0.74, and 0.39 x 10(6)/kg. Following transplantation, the median times to an absolute neutrophil count (ANC) > 0.5 x 10(9)/L were 12, 15, and 12 days, respectively, and the median times to platelet transfusion independence were 30, 19, and 15 days.

CONCLUSION

PIXY321 can be safely administered and effectively mobilizes PBC in patients with bone marrow defects. PIXY321-mobilized PBC autotransplants result in rapid and sustained hematopoietic recovery.

In vivo haemoprotective activity of tetrapeptide AcSDKP combined with granulocyte-colony stimulating factor following sublethal irradiation

We report that acetyl-N-Ser-Asp-Lys-Pro (AcSDKP), which removes progenitor cells from cell cycle, in combination with granulocyte-colony stimulating factor (G-CSF) can significantly improve myelorestoration following irradiation (7 Gy). Peripheral blood, spleen and bone marrow (BM) cell recovery and progenitor cell reconstitution [IL-3-responsive colony-forming cells (CFC) and high proliferative potential colony-forming cells (HPP-CFC)] were studied. Studies on the optimal schedule of AcSDKP administration revealed maximal effects on progenitor cells when AcSDKP was administered as a continuous infusion for 3 d starting 24 h prior to irradiation and used in combination with G-CSF. The numbers of CFC and HPP-CFC in the BM were significantly increased following irradiation in mice receiving AcSDKP and G-CSF as compared to either drug alone. The numbers of CFC in the spleen were significantly increased in mice receiving AcSDKP and G-CSF on days 10 and 14 as compared to AcSDKP alone, but not G-CSF. Similarly, CFC and HPP-CFC in the spleen were significantly increased in mice receiving AcSDKP and G-CSF on day 18 as compared to mice receiving PBS and G-CSF. These studies suggest that AcSDKP in combination with G-CSF may have potential for the protection of progenitor cells in patients undergoing intensive chemo- and/or radiotherapy.

Role of DNA sequences outside the cores of DNase hypersensitive sites (HSs) in functions of the beta-globin locus control region. Domain opening and synergism between HS2 and HS3

The roles of each DNase hypersensitive site (HS), and the DNA sequences between them, in the activity of the locus control region of the mammalian beta-globin gene domain were examined by placing human and rabbit restriction fragments containing the cores of HS2, HS3, HS4, and HS5, along with varying amounts of flanking DNA, upstream of a hybrid epsilon-globin-luciferase reporter gene and testing for effects on expression both prior to and after integration into the chromosomes of K562 cells, a human erythroid cell line. Prior to integration, fragments containing HS2 enhanced expression to the greatest extent, and the modest enhancement by some fragments containing HS3 correlated with the presence of a well-conserved binding site for AP1/NFE2. The stronger effects of larger locus control region DNA fragments in clones of stably transfected cells indicates a role for sequences outside the HS cores after integration into the genome. The strong effect of a 1.9-kilobase HindIII fragment containing HS3 after, but not prior to, integration argues for the presence of a chromatin domain-opening activity. Use of a rabbit DNA fragment containing both HS2 and HS3 demonstrated a synergistic interaction between the two HSs when their natural context and spacing are preserved.

In vivo protective effects of tetrapeptide AcSDKP, with or without granulocyte colony-stimulation factor, on murine progenitor cells after sublethal irradiation

Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) demonstrated hemato-protective activity in mice after sublethal irradiation (7 GY). Bone marrow interleukin-3 (IL-3)-responsive colony-forming cells (CFC and high proliferative potential colony-forming cells (HPP-CFC) were significantly (p < 0.05) increased by day 10 after irradiation in mice receiving a continuous infusion of 1000 ng/day of AcSDKP compared to irradiated control mice. The maximum protective effect for bone marrow progenitors was achieved when AcSDKP was administered for 3 days beginning 24 hours before irradiation. Other dosages and schedules in relationship to irradiation were less active. Further, when granulocyte colony-stimulating factor (G-CSF) was administered for 10 days beginning 24 hours before irradiation. Other dosages and schedules in relationship to irradiation were less active. Further, when granulocyte colony-stimulating factor (G-CSF) was administered for 10 days after AcSDKP infusion in irradiated mice, significantly increased numbers of IL-3 responsive CSF-only control mice. In addition, platelets were significantly (p < 0.05) increased in mice receiving AcSDKP and G-CSF on days 18 and 21 after irradiation compared with mice receiving G-CSF alone. We conclude that ACSDKP has a radioprotective effect in vivo for progenitor cells, and that time of initiation and duration of AcSDKP administration relative to irradiation are crucial for these effects. Further, AcSDKP has a significant additive protective effect not only for progenitor cells but also for platelets when given in combination with G-CSF. We suggest that these in vivo observations provide a basis on which to design optimal clinical hypothesis and protocols.

Activity of acetyl-n-ser-asp-lys-pro (AcSDKP) on hematopoietic progenitor cells in short-term and long-term murine bone marrow cultures

The tetrapeptide AcSDKP is a potent inhibitor of hematopoietic stem cell proliferation. Its activity was systematically examined in murine long-term bone marrow cultures (LTBMC) and short-term liquid cultures in the presence or absence of exogenous cytokines. The effects of AcSDKP on the production of granulocyte-macrophage colony-forming cells (CFU-GM) and high proliferative potential colony-forming cells (HPP-CFC) in LTBMCs were examined. AcSDKP was added daily to LTBMCs at various concentrations (10-3--10-16M) for up to 5 weeks. AcSDKP inhibited the entry of progenitor cells into S phase as measured by 3H-thymidine suicide assay and the absolute number of progenitor cells with peak activity at 10-12 M with less activity seen at higher or lower concentrations. The number of nonadherent CFU-GM per LTBMC was unchanged from control values at 1 week of treatment with AcSDKP but was significantly depressed at weeks 3 and 5. In contrast, HPP-CFC progenitor cells were decreased throughout the treatment period, and the numbers of CFU-GM and HPP-CFC in S phase were significantly decreased throughout the treatment period. Maximum S-phase inhibitory activity was observed at 10-12 M AcSDKP. AcSDKP had no effect on the number of adherent CFU-GM or HPP-CFC, cellularity per culture or percent of adherent progenitor cells in S phase. Murine short-term bone marrow cultures were also treated with AcSDKP in the presence or absence of cytokines (interleukin-3 [LI-3], stem cell factor [SCF], or granulocyte colony-stimulating factor [G-CSF]) for various time periods. Dose-response studies showed maximum effects at 10-12 M AcSDKP when no cytokines were added and 10-14 M AcSDKP when exogenous cytokines were added. These studies indicate that the concentration of the tetrapeptide critical in obtaining an effect on hematopoietic progenitor cells, and furthermore, we report that the presence of cytokines or stromal cells also affects the response of progenitor cells to AcSDKP.

Immunologic attributes of cytokine mobilized peripheral blood stem cells and recovery following transplantation

The immunologic attributes of cytokine mobilized peripheral blood stem cell (PSC) products (n = 52) and the resulting reconstitution of the hematopoietic and immunologic system following autologous transplantation were examined in a consecutive population of non-Hodgkin lymphoma (NHL), or solid tumor patients at the University of Nebraska Medical Center. Granulocyte-monocyte colony stimulating factor (GM-CSF)-mobilized PSC products had a high frequency of monocytes (31%) and bands (15%) as compared to normal peripheral blood (PB) cells. The phenotypic analysis of the mobilized PSC product revealed that they had normal levels of CD4+ cells, an increased frequency of CD8+ cells and a corresponding decrease in the CD4+:CD8+ cell ratio as compared to the peripheral blood leukocytes (PBL) of normal individuals. PSC products also had an increase in CD34+ cells as compared to PB. Natural killer (NK) and T cell activity in the PSC products were also lower than that observed in PB. Post-transplantation there was an accelerated reconstitution of NK-cell function in the PB as compared to T cell function (PHA (phytohemagglutinin) mitogenesis) which did not return to normal by day 100 post-transplantation. We also report for the first time high levels of an irradiation resistant suppressor cell activity in the PSC product and in the PB post-transplantation. There was also a concomitant increase in CD4-, CD8-, TCR alpha/beta+ cells (phenotypic homolog of 'natural suppressor' (NS) cells) in the PB post-transplantation. The number of months of prior chemotherapy correlated with PHA response but the NS activity and frequency of CD4-, CD8- and TCR alpha/beta+ cells did not. Further, cytokine mobilization and apheresis appears to contribute to the loss of PHA responsiveness and the increased levels of suppressor cell activity.

Effects of BCR-ABL antisense oligonucleotides (AS-ODN) on human chronic myeloid leukemic cells: AS-ODN as effective purging agents

We examined phosphorothioate oligodeoxyribonucleotides (ODNs) directed against bcr in exon 3 or exon 2, which are rearranged with exon 2 of abl (B3A2 and B2A2) at t(9;22) of chronic myelogenous leukemia (CML). Since these ODNs are designed to be CML cell specific, we studied their effects on the human CML cell line K562, which is known to have B3A2 rearrangement, and leukemic cells from patients, as well as normal hematopoietic stem cells in vitro. In vitro experiments were performed to determine a potential role of these two ODNs as ex vivo purging agents. Incubation of B3A2 antisense at 40, 80, and 120 micrograms/ml with K562 CML cells for 72 hours at 37 degrees C resulted in 44%, 56%, and 63% reduction of CFU-L as compared to controls. In contrast, B3A2 sense and B2A2 antisense had no significant growth inhibitory effect on K562 cells. Incubation of B3A2 and B2A2 antisense ODNs at concentration of 80 micrograms/ml at 37 degrees C for 36 hours with normal peripheral blood stem/progenitor cells (PBSC) resulted in 124% and 98% CFU-GM formation as compared to untreated controls, respectively. However, incubation of PBSC with B3A2 and B2A2 sense-ODNs resulted in a 22% and 44% reduction in CFU-GM, respectively. In order to determine the ex vivo purging effects of bcr-abl ODNs, the K562 cells were mixed with PBSC from normal donors at a ratio of 1:20 (CML:PBSC). The mixture of cells was then incubated with B3A2 antisense at 80 micrograms/ml for 36 hrs at 37 degrees C. After incubation, no CML cells were detected by fluorescence in situ hybridization (FISH) as compared to untreated controls. These results were confirmed by RT-PCR using bcr-abl primers and mRNA isolated from the mixture of cells. Further, these results support the hypothesis that bcr-abl antisense ODNs are potentially effective agents for ex vivo purging of autologous stem cells before transplantation to eliminate/reduce the burden of leukemic cells. No significant toxicity to normal hematopoietic stem/progenitor cell population by the bcr-abl antisense ODNs was observed. Although unanticipated reductions in normal hematopoietic progenitor cells (CFU-GM) were observed with sense ODNs, no reduction in CFU-GM was observed with unrelated phosphorothioate ODN controls.

Erythropoietin for mobilization of circulating progenitor cells in patients with previously treated relapsed malignancies

A trial to determine the usefulness of recombinant human erythropoietin (rhEpo) as a mobilizing cytokine for patients with previously treated relapsed malignancies was performed. An initial peripheral stem cell apheresis collection was conducted during steady-state hematopoiesis for each patient to provide baseline data. rhEpo, 200 U/kg/day, was administered subcutaneously until the last apheresis procedure was completed. Immediately after the fourth daily dose of Epo, apheresis procedures were resumed and continued beyond five collections, when necessary, to accrue a total of 6.5 x 10(8) mononuclear cells (MNCs)/kg. Eight female and four male patients (median age = 44 years) were evaluated. Five to 14 (median = 8) apheresis procedures were performed for each patient. Toxicity attributable to Epo administration was negligible. Mobilization effects, as determined by an increase in the number of colony-forming units granulocyte/macrophage (CFU-GM) and burst-forming units-erythroid (BFU-E) in the apheresis products after Epo administration, were observed in all patients. Nine patients received high-dose chemotherapy and Epo-mobilized peripheral stem cell transplantation (PSCT). Beginning the day of the transplant, GM-CSF was administered until neutrophil recovery was satisfactory. The median time to recover 0.5 x 10(9)/L granulocytes was 16 days after PSCT. Epo appears to have mobilization properties. Further studies are needed to determine the clinical usefulness of Epo as a mobilizing cytokine. The addition of Epo to other mobilizing cytokines may provide increased effectiveness without adding toxicity.

Interleukin-12 enhances peripheral hematopoiesis in vivo

Interleukin 12(IL-12) is a cytokine that supports the proliferation and activation of cytotoxic T lymphocytes and natural killer (NK) cells. Recent evidence has suggested that IL-12 also has hematopoietic activities in vitro. We report studies that show that IL-12 has significant in vivo hematopoietic stimulating activity that includes enhancement of peripheral (splenic) hematopoiesis and mobilization of hematopoietic progenitor cells to the peripheral circulation. A single injection of recombinant murine IL-12 significantly reduced the number of bone marrow (BM) colony-forming unit granulocyte-macrophage (CFU-GM) in a time-dependent manner, while concomitantly stimulating high proliferative potential. In contrast, splenic CFU-GM and HPP were increased in a time- and dose-dependent manner. Chronic administration of IL-12 resulted in significant splenic hyperplasia with increased progenitor cells, increased circulating progenitor cells, and BM hypoplasia with decreased progenitor cells. These data show that IL-12 has significant in vivo hematopoietic effects that include the ability to mobilize progenitor cells to the peripheral circulation, which may prove to be of significant benefit for peripheral blood stem cell transplantation. Thus, IL-12 has potential to be an important agent for clinical transplantation because of its hematopoietic mobilization and its previously shown immune augmenting and therapeutic activities. This combination of hematopoietic and immune functions is unique and not achievable with currently used hematopoietic growth factors.

Functional and phenotypic characterization of human peripheral blood stem cell harvests: a comparative analysis of cells from consecutive collections

A considerable number of patients with malignancies who are treated with high-dose therapy and hematopoietic stem cell transplantation subsequently relapse. Analyses of peripheral blood stem cell (PBSC) harvests obtained from 49 cancer patients showed that the PBSC harvest contained precursors for antitumor effector cells. Ex vivo manipulation of these harvests to maximize the antitumor effector cell activity may provide a new therapeutic approach to decrease or eliminate any minimal residual disease that remains after high-dose therapy. Characterization of PBSC from consecutive collections determined the collections best suited for ex vivo augmentation of antitumor cytotoxic effector cells. We report the results of a functional and phenotypical characterization of PBSC obtained from six consecutive collections from 18 cancer patients receiving granulocyte-macrophage colony-stimulating factor (GM-CSF) for hematopoietic stem/progenitor cell mobilization. The PBSC were evaluated for their cytotoxicity using the 51Cr-release assay. The frequency and subsets of lymphocytes were determined using flow cytometry with appropriate specific marker antibodies and differential cell counts. The content of hematopoietic progenitor cells in each collection was determined using a colony-forming unit granulocyte-macrophage (CFU-GM) culture assay. The frequency of cytotoxic effector cells including lymphokine-activated killer (LAK) cell precursors and lymphocytes was significantly greater (P < .05) in the early collections, whereas the later collections contained significantly (P < .05) more CFU-GM progenitor cells and fewer cytotoxic effector cells. Thus, our results show that PBSC obtained from advanced cancer patients do contain considerable levels of precursor cells for the generation of LAK cell populations. These results suggest that cells from the earlier collections are best suited for ex vivo manipulation to augment the antitumor effects.

Fatal eosinophilic disease following autologous bone marrow transplantation

A 15-year-old girl developed massive, fatal eosinophilic disease following autologous bone marrow transplantation (BMT) for Hodgkin's disease (HD). Prior to autologous BMT, the erythrocyte sedimentation rate (ESR) was elevated, with active HD, but eosinophilia was absent. Post-autologous BMT, ESR and peripheral eosinophilia were observed to correlate with respiratory symptoms. Initial evaluation revealed no recurrent tumor, infection or other identifiable etiology. A diagnosis of chronic eosinophilic pneumonia was made following lung biopsy. A complete response was initially achieved with steroid therapy; however, when steroid therapy was tapered, the eosinophilia and elevated ESR recurred with worsening respiratory symptoms. Terminally, severe pulmonary disease developed and recurrent HD was found in lung, lymph nodes and bone marrow. During episodes of eosinophilia, the patient's serum stimulated her bone marrow as well as control marrow to produce predominantly eosinophilic colonies. Eosinophilic colony production was not observed with patient's sera obtained prior to or during autologous BMT or with control sera. This patient died of eosinophilic inflammatory disease following autologous BMT. The etiology of this disease was not definitely identified but appeared to be due to an eosinophilic-stimulating factor which developed after autologous BMT.

Differential recovery of polymorphonuclear neutrophils, B and T cell subpopulations in the thymus, bone marrow, spleen and blood of mice following split-dose polychemotherapy

In these studies, we examined the effect of a maximum-tolerated, split-dose chemotherapy protocol of cyclophosphamide, cisplatin, and 1,3-bis(2-chloroethyl)-1-nitrosourea carmustine on neutrophil and lymphocyte, subpopulations in the peripheral blood (PBL), thymus, bone marrow and spleen. It was found that this protocol of polychemotherapy, modeled after the induction protocol used with autologous bone marrow transplantation for breast cancer, suppressed both B and T cell populations and T cell function at times when the absolute neutrophil count had returned to normal or supernormal numbers. In the peripheral blood, 7 days following initiation of chemotherapy, there was a twofold increase in the percentage of granulocytes as compared to the level in control animals on the basis of a differential count. The polymorphonuclear neutrophil (PMN) frequency in the bone marrow was increased on day 14 and statistically identical to that in control mice on all other days analyzed. In contrast to the bone marrow cells and PBL on day 7, the frequency of PMN in the spleen and thymus was depressed. B cells (B220+) were depressed in the pBL, spleen and bone marrow and took 18-32 days to return to their normal frequency, while the frequency of B cells in the thymus was increased owing to a loss of immature T cells. The percentage of CD3+ cells in the thymus, spleen and bone marrow was significantly increased and required 10-18 days to return to normal levels, while the absolute number of CD3+ cells in the blood varied around the normal value. The ratio of CD4+ to CD8+ cells in all the organs studied varied only slightly owing to a similar reconstitution of CD4+ and CD8+ cells. In contrast to the phenotypic recovery of the CD3+, CD4+, and CD8+ cells, the ability of the splenic lymphocytes to respond to concanavalin-A was depressed and remained depressed, despite the phenotypic reconstitution of the T cell subsets, on the basis of both percentage and absolute cell number. These results show a selective T and B cell depression following multi-drug, split-dose chemotherapy in tissue and blood leukocyte populations and a chronic depression in T cell function.