Practical and Safe Method of Long-Term Cryopreservation for Clinical Application of Human Adipose-Derived Mesenchymal Stem Cells Without a Programmable Freezer Or Serum

BACKGROUND

Adipose-derived mesenchymal stem cells (ADSCs) have emerged as a promising modality for cellular therapy. However, techniques of ADSC cryopreservation, which can facilitate their clinical application, haven't been established yet.

OBJECTIVE

To determine optimal conditions for ADSC cryopreservation.

MATERIALS AND METHODS

We used three cryoprotectants [serum containing 10% dimethyl sulfoxide; CP-1^TM (5% dimethyl sulfoxide, serum-free); Stem-CellBanker^TM (dimethyl sulfoxide and serum-free)], two storage temperatures (-80°C, -150°C) and two cell densities (1 × 10⁶, 7 × 10⁶ cells/mL). Storage was up to 18 months using cryovials. We didn't use a rate-controlled freezer or liquid nitrogen storage.

RESULTS

We found that CP-1^TM was a suitable cryoprotectant. Storage at -150°C and higher cell density (7×10⁶ cells/mL) kept the best viability of ADSCs, but storage at -80°C and a lower cell density (1×10⁶ cells/mL) is acceptable for up to 9 months. We also confirmed large quantities of ADSCs, stored with CP-1 in a cryobag, were still viable after -150°C cryopreservation for 24 months.

CONCLUSION

We have developed a safe, cost-effective way to cryopreserve ADSCs that could be used in the clinical setting.

Emerging investigator series: investigation of mercury emission sources using Hg isotopic compositions of atmospheric mercury at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS), Japan

This study conducted mercury (Hg) isotopic analysis, which has been expected as a new indicator for understanding the behavior of atmospheric Hg. The dominant atmospheric Hg species, namely gaseous elemental mercury (GEM, Hg0), were collected at the Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) in Okinawa, Japan, for evaluating possible source(s) and transformation process(es) of Hg. The Hg isotopic compositions of GEM samples showed that the mass-dependent fractionation (MDF) of δ202Hg and the mass-independent fractionation (MIF) of Δ199Hg ranged from -2.15‰ to 0.79‰ and from -0.32‰ to 0.00‰, respectively. The results were classified into two groups: (1) negative δ202Hg and near-zero Δ199Hg in summer and (2) near-zero δ202Hg and negative Δ199Hg in the other season. According to the NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the dominant air masses traveled from East Asia during winter and South and East Asia during summer. However, the air masses also traveled from mainland Japan and rotated around Okinawa before reaching CHAAMS. In contrast, clear positive correlations between δ202Hg values and CO and PM2.5 concentrations were observed during summer. A small peak of Ox concentration was observed at three atmospheric monitoring stations, namely Nago, Naha, and Miyako Island during summer. Since Miyako Island is located ∼370 km southwest of CHAAMS, the main emission source of GEM transported to CHAAMS was not from mainland Okinawa but traveled from the southwest during summer.

Early-shared Mycobacterium bovis bacillus Calmette-Guérin sub-strains induce Th1 cytokine production in vivo

Interleukin-12 is one of the cytokines that induce acquired immunity by progressing the differentiation of T cells. When antigens are presented by APCs, including macrophages and DCs, T cells are activated and produce the Th1 cytokines IL-2 and IFN-γ. We have previously reported greater IL-12 production from macrophages infected with early-shared BCG sub-strains (ex. BCG-Japan, -Sweden) than from those infected with late-shared BCG (ex. BCG-Pasteur and -Connaught) . In this study, we investigated the Th1 cytokine-inducing activity of splenocytes co-cultured with BCG-infected DCs. Early-shared BCG-infected DCs produced IL-12 and TNF-α⋅ Furthermore, when they were co-cultured with purified protein derivative-stimulated DCs, the splenocytes of mice immunized with BCG-Tokyo/Japan produced more Th1 cytokine than did those of mice immunized with BCG-Connaught. In conclusion, early-shared BCG sub-strains more strongly induce Th1 cytokine production in vivo. This study provides basic information to inform the selection of candidates for primary vaccination.

Pharmacodynamics of the glucagon-like peptide-1 receptor agonist lixisenatide in Japanese and Caucasian patients with type 2 diabetes mellitus poorly controlled on sulphonylureas with/without metformin

AIMS

The PDY6797 study evaluated efficacy, safety and pharmacodynamics of lixisenatide in Japanese and Caucasian patients with type 2 diabetes mellitus (T2DM) insufficiently controlled with sulphonylureas with/without metformin.

METHODS

This randomized, double-blind, placebo-controlled trial comprised a single-dose assessment of lixisenatide 5 and 10 µg, and a 5- to 6-week repeated dose-escalation assessment of lixisenatide 5 to 30 µg once (QD) or twice daily (BID). The primary endpoint was change in postprandial plasma glucose (PPG) area under the curve (AUC)[0:29-4:30 h] after a standardized breakfast at the highest tolerated lixisenatide dose. Change from baseline in glycated haemoglobin (HbA1c), 2-h PPG and fasting plasma glucose (FPG) were assessed, as were adverse events.

RESULTS

Change from baseline in PPG AUC[0:29-4:30 h] with lixisenatide QD and BID was significantly greater than placebo (p < 0.0001 for all study populations), with particularly prominent effects in Japanese patients. Greater reductions in PPG AUC[0:29-4:30 h] were seen with lixisenatide QD versus BID, while the totality of evidence suggested that the lixisenatide 20 µg dose was optimal. In the overall population, changes from baseline for 2-h PPG, HbA1c and FPG were significant with lixisenatide QD and BID versus placebo (p < 0.01 for all). Lixisenatide was well tolerated.

CONCLUSIONS

Lixisenatide significantly reduced PPG AUC[0:29-4:30 h] versus placebo at the highest well-tolerated dose in patients with T2DM treated with sulphonylureas with/without metformin and had a good safety and tolerability profile. Japanese patients experienced particular benefits with lixisenatide in terms of reductions in PPG excursions.

Successful hyperbaric oxygen therapy for refractory BK virus-associated hemorrhagic cystitis after cord blood transplantation

BK virus-associated hemorrhagic cystitis (BKV-HC) is a common and major cause of morbidity in recipients of allogeneic hematopoietic stem cell transplantation. A 32-year-old woman developed severe BKV-HC on day 24 after cord blood transplantation (CBT). Despite supportive therapies - such as hyperhydration, forced diuresis, and urinary catheterization - macroscopic hematuria and bladder irritation persisted for over a month. Hyperbaric oxygen (HBO) therapy at 2.1 atmospheres for 90 min per day was started on day 64 after CBT. Macroscopic hematuria resolved within a week, and microscopic hematuria was no longer detectable within 2 weeks. Hematuria did not recur after 11 sessions of HBO therapy, and no significant side effects were observed during or after treatment. HBO therapy could thus be useful in controlling refractory BKV-HC after CBT.

Relative incidences and outcomes of Clostridium difficile infection following transplantation of unrelated cord blood, unrelated bone marrow, and related peripheral blood in adult patients: a single institute study

BACKGROUND

Clostridium difficile is a major cause of nosocomial diarrhea. The incidence and prognosis of C. difficile-associated diarrhea (CDAD) has not yet been assessed in adult patients after unrelated cord blood transplantation (uCBT).

METHODS

The medical records of 135 adult unrelated cord blood transplant recipients were reviewed retrospectively to investigate the clinical features of CDAD after uCBT. These data were compared to medical records of 39 unrelated bone marrow transplant recipients and 27 related peripheral blood stem cell transplant recipients as controls.

RESULTS

A total of 17 recipients developed CDAD, with onset occurring at a median of 22 days (range, 0-56 days) after transplantation. Among the unrelated cord blood transplant recipients, 11 (9%) developed CDAD. These results were comparable with those of CDAD after unrelated bone marrow transplantation (uBMT) (2/39, 6%) and related peripheral blood stem cell transplantation (rPBSCT) (4/27, 16%) (P=0.37). Fifteen of the infected recipients were successfully treated with oral metronidazole, vancomycin, or cessation of antibiotics. The remaining 2 recipients who developed CDAD after uCBT died of other causes. The development of CDAD did not negatively affect overall survival after uCBT.

CONCLUSIONS

These data indicate that the incidence and prognosis of CDAD after uCBT are comparable with those after uBMT and rPBSCT.

Randomized, double-blind, placebo-controlled trial of the once-daily GLP-1 receptor agonist lixisenatide in Asian patients with type 2 diabetes insufficiently controlled on basal insulin with or without a sulfonylurea (GetGoal-L-Asia)

AIMS

To assess the efficacy and safety of once-daily lixisenatide versus placebo in Asian patients with type 2 diabetes insufficiently controlled on basal insulin ± sulfonylurea.

METHODS

In this 24-week, randomized, double-blind, placebo-controlled, parallel-group, multicentre study, participants (mean baseline HbA(1c) 8.53%) from Japan, Republic of Korea, Taiwan and the Philippines received lixisenatide (n = 154) or placebo (n = 157) in a stepwise dose increase to 20 µg once daily. The primary endpoint was HbA(1c) change from baseline to week 24.

RESULTS

Once-daily lixisenatide significantly improved HbA(1c) versus placebo (LS mean difference vs. placebo = -0.88% [95%CI= -1.116, -0.650]; p < 0.0001), and allowed more patients to achieve HbA(1c) <7.0% (35.6 vs. 5.2%) and ≤ 6.5% (17.8 vs. 1.3%). Lixisenatide also significantly improved 2-h postprandial plasma glucose and glucose excursion, average 7-point self-monitored blood glucose and fasting plasma glucose. Lixisenatide was well tolerated; 86% of patients on lixisenatide completed the study versus 92% on placebo. Ten (6.5%) lixisenatide and 9 (5.7%) placebo patients experienced serious adverse events. More lixisenatide patients [14 (9.1%)] discontinued for adverse events versus placebo [5 (3.2%)], mainly with gastrointestinal causes. Nausea and vomiting were reported in 39.6 and 18.2% of patients on lixisenatide versus 4.5 and 1.9% on placebo. Symptomatic hypoglycaemia was more frequent with lixisenatide (42.9%) versus placebo (23.6%), but was similar between groups (32.6 vs. 28.3%, respectively), in those not receiving sulfonylureas. No severe hypoglycaemia was reported.

CONCLUSIONS

In an Asian type 2 diabetes population insufficiently controlled by basal insulin  ±  sulfonylurea, once-daily lixisenatide significantly improved glycaemic control, with a pronounced postprandial effect, and was well tolerated.

Randomized, double-blind, placebo-controlled trial of the once-daily GLP-1 receptor agonist lixisenatide in Asian patients with type 2 diabetes insufficiently controlled on basal insulin with or without a sulfonylurea (GetGoal-L-Asia)

AIMS

To assess the efficacy and safety of once-daily lixisenatide versus placebo in Asian patients with type 2 diabetes insufficiently controlled on basal insulin ± sulfonylurea.

METHODS

In this 24-week, randomized, double-blind, placebo-controlled, parallel-group, multicentre study, participants (mean baseline HbA(1c) 8.53%) from Japan, Republic of Korea, Taiwan and the Philippines received lixisenatide (n = 154) or placebo (n = 157) in a stepwise dose increase to 20 µg once daily. The primary endpoint was HbA(1c) change from baseline to week 24.

RESULTS

Once-daily lixisenatide significantly improved HbA(1c) versus placebo (LS mean difference vs. placebo = -0.88% [95%CI= -1.116, -0.650]; p < 0.0001), and allowed more patients to achieve HbA(1c) <7.0% (35.6 vs. 5.2%) and ≤ 6.5% (17.8 vs. 1.3%). Lixisenatide also significantly improved 2-h postprandial plasma glucose and glucose excursion, average 7-point self-monitored blood glucose and fasting plasma glucose. Lixisenatide was well tolerated; 86% of patients on lixisenatide completed the study versus 92% on placebo. Ten (6.5%) lixisenatide and 9 (5.7%) placebo patients experienced serious adverse events. More lixisenatide patients [14 (9.1%)] discontinued for adverse events versus placebo [5 (3.2%)], mainly with gastrointestinal causes. Nausea and vomiting were reported in 39.6 and 18.2% of patients on lixisenatide versus 4.5 and 1.9% on placebo. Symptomatic hypoglycaemia was more frequent with lixisenatide (42.9%) versus placebo (23.6%), but was similar between groups (32.6 vs. 28.3%, respectively), in those not receiving sulfonylureas. No severe hypoglycaemia was reported.

CONCLUSIONS

In an Asian type 2 diabetes population insufficiently controlled by basal insulin  ±  sulfonylurea, once-daily lixisenatide significantly improved glycaemic control, with a pronounced postprandial effect, and was well tolerated.

Successful treatment of Trichosporon fungemia in a patient with refractory acute myeloid leukemia using voriconazole combined with liposomal amphotericin B

Trichosporon fungemia is a rare and fatal fungal infection that occurs in patients with prolonged neutropenia associated with hematologic malignancies. A 21-year-old male developed Trichosporon fungemia during remission induction therapy for acute myeloid leukemia (AML). Although two courses of induction therapy failed to induce a remission of AML, combination therapy with voriconazole and liposomal amphotericin B (L-AmB) followed by monocyte colony-stimulating factor ameliorated the Trichosporon fungemia and enabled the patient to receive reduced-intensity bone marrow transplantation (BMT) from his human leukocyte antigen-A one-locus mismatched mother. The patient achieved a durable remission after BMT without exacerbation of Trichosporon fungemia. The combination therapy with voriconazole and L-AmB may therefore be useful in controlling Trichosporon fungemia associated with prolonged neutropenia after remission induction therapy for AML.

Allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia with t(6;9)(p23;q34) dramatically improves the patient prognosis: a matched-pair analysis

Acute myeloid leukemia (AML) with t(6;9)(p23;q34) is well known to have a poor prognosis treated with chemotherapy and autotransplantation. The presence of this karyotype is an indicator for allogeneic hematopoietic stem cell transplantation (HSCT); however, the impact of t(6;9)(p23;q34) on the HSCT outcome remains unclear. We conducted a matched-pair analysis of de novo AML patients with and without t(6;9)(p23;q34) using data obtained from the Japanese HSCT data registry. A total of 57 patients with t(6;9)(p23;q34) received transplants between 1996 and 2007, and 171 of 2056 normal karyotype patients matched for age, disease status at HSCT and graft source were selected. The overall survival, disease-free survival, cumulative incidence of relapse and the non-relapse mortality in t(6;9)(p23;q34) patients were comparable to those for normal karyotype patients. A univariate analysis showed that t(6;9)(p23;q34) had no significant impact on the overall survival. These findings suggest that allogeneic HSCT may overcome the unfavorable impact of t(6;9)(p23;q34) as an independent prognostic factor.

Immature platelet fraction for prediction of platelet engraftment after allogeneic stem cell transplantation

Platelet regeneration represents an important and separate element in the engraftment process for allogeneic stem cell transplantation. Fully automated flow cytometry using blood cell counters now allows reliable quantification of reticulated platelets, expressed as the immature platelet fraction (IPF). We studied the kinetics of IPF in six patients grafted with allogeneic peripheral blood stem cell transplantation (PBSCT), 12 patients with bone marrow transplantation (BMT) and seven patients with cord blood transplantation (CBT). Preconditioning therapy caused an immediate and rapid fall in tri-lineage hematopoiesis. IPF rose transiently above 3% after a mean duration of 11 days post-PBSCT, 18 days post-BMT and 19 days post-CBT. This was 1, 4 and 13 days earlier than platelet engraftment, respectively. A linear correlation model showed a close association between the rise of IPF and tri-lineage engraftment after transplantation. IPF counting may thus provide an accessible measure of thrombopoietic activity, leading to early evaluation of marrow function and allowing monitoring of platelet regeneration.

Safety and Efficacy of Foscarnet for Preemptive Therapy Against Cytomegalovirus Reactivation After Unrelated Cord Blood Transplantation

In association with the increased use of unrelated cord blood transplantation (UCBT) in adults, numerous patients have developed cytomegalovirus (CMV) reactivation concomitant with cytopenia. Although foscarnet appears to offer similar efficacy and higher safety as a preemptive therapy against CMV infection than ganciclovir, little is known about the usefulness of foscarnet in such patients. Foscarnet was administered as preemptive therapy against CMV antigenemia in 10 UCBT recipients who were unable to receive ganciclovir due to cytopenia or poor response to ganciclovir. Fatal CMV disease developed in one patient, whereas CMV antigenemia resolved without progression to CMV disease in the remaining nine patients. Foscarnet was well tolerated without serious hematotoxicity and was not discontinued due to adverse events in any patient. Foscarnet represents a safe and effective agent for preemptive therapy against CMV infection and may offer a feasible alternative to ganciclovir in UCBT recipients.

Reduced-intensity unrelated cord blood transplantation for treatment of metastatic renal cell carcinoma: first evidence of cord-blood-versus-solid-tumor effect

We report a 69-year-old man with cytokine-resistant metastatic renal cell carcinoma treated with reduced-intensity unrelated cord blood transplantation. The patient achieved durable donor engraftment with minimal graft-versus-host disease. The patient showed regression of metastatic disease, providing the first evidence of a graft-versus-tumor effect on a solid tumor resulting from cord blood graft.

Expansion and activation of minor histocompatibility antigen HY-specific T cells associated with graft-versus-leukemia response

The immune system of females is capable of recognizing and reacting against the male-specific minor histocompatibility antigen (mHA), HY. Thus, cytotoxic T-lymphocytes (CTLs) recognizing this antigen may be useful in eradicating leukemic cells of a male patient if they can be generated in vivo or in vitro from a human leukocyte antigen (HLA)-identical female donor. The HLA-A*0201-restricted HY antigen, FIDSYICQV, is a male-specific mHA. Using HLA-A2/HY peptide tetrameric complexes, we reveal a close association between the emergence of HY peptide-specific CD8(+) T cells in peripheral blood and molecular remission of relapsed BCR/ABL(+) chronic myelogenous leukemia in lymphoid blast crisis in a patient who underwent female-to-male transplantation. Assessment of intracellular cytokine levels identified T cells that produce interferon-gamma in response to the HY peptide during the presence of HY tetramer-positive T cells. These results indicate that transplant with allogeneic HY-specific CTLs has therapeutic potential for relapsed leukemia, and that expansion of such T cells may be involved in the development of a graft-versus-leukemia response against lymphoblastic leukemia cells.

Enhancement of cyclosporin A-induced autologous graft-versus-host disease after peripheral blood stem cell transplantation by utilizing selected CD34+ cells

Although autologous graft-versus-host disease (GVHD) can be induced by administration of cyclosporin A (CsA) after peripheral blood stem cell transplantation (PBSCT), the incidence appears to be remarkably lower compared to the incidence after bone marrow transplantation. The reduced incidence of autologous GVHD after PBSCT may be attributed to peripheral regulatory cells that are transferred with the stem cell inoculum. To determine whether transplantation of CD34-selected peripheral blood stem cells (PBSCs) leads to potentiation of autologous GVHD, five patients with malignant lymphoma were transplanted with CD34-selected PBSCs, followed by administration of CsA and interferon (IFN)-gamma. Inducibility of autologous GVHD and autocytotoxic activities of peripheral blood mononuclear cells (PBMCs) after transplantation were assessed. All patients demonstrated prompt hematologic recovery. Cytotoxic activity of PBMCs against autologous lymphocytes was detectable in four of four patients analyzed during a limited period from days 14 to 34 post-transplant. An erythematous rash compatible with GVHD, confirmed by skin biopsy, developed in three of five patients. One of the three patients developed not only skin, but also gut and liver GVHD. Transplantation of the CD34-selected stem cell graft that does not accompany transfusion of regulatory cells may potentiate the inducibility of autologous GVHD by the administration of CsA and IFN-gamma.

Washout studies of 11C in rabbit thigh muscle implanted by secondary beams of HIMAC

Heavy ion therapy has two definite advantages: good dose localization and higher biological effect. Range calculation of the heavy ions is an important factor in treatment planning. X-ray CT numbers are used to estimate the heavy ion range by looking up values in a conversion table which relates empirically photon attenuation in tissues to particle stopping power; this is one source of uncertainty in the treatment planning. Use of positron emitting radioactive beams along with a positron emission tomograph or a positron camera gives range information and may be used as a means of checking in heavy ion treatment planning. However, the metabolism of the implanted positron emitters in a living object is unpredictable because the chemical forms of these emitters are unknown and the metabolism is dependent on the organ species and may be influenced by many factors such as blood flow rate and fluid components present. In this paper, the washout rate of 11C activity implanted by injecting energetic 11C beams into thigh muscle of a rear leg of a rabbit is presented. The washout was found to consist of two components, the shorter one was about 4.2 +/- 1.1 min and the longer one ranged from 91 to 124 min. About one third of the implanted beta+ activity can be used for imaging and the rest was washed out of the target area.

Menatetrenone, a vitamin K2 analog, ameliorates cytopenia in patients with refractory anemia of myelodysplastic syndrome

Vitamin K2 induces differentiation of leukemic cell lines and apoptosis of immature blasts in myelodysplastic syndrome (MDS). We recently reported a case of MDS-refractory anemia (MDS-RA) with trilineage hematologic response to oral administration of menatetrenone, a vitamin K2 analog. To determine a possible role of this agent in treatment of MDS-RA, we conducted a prospective randomized trial assessing the safety and efficacy of menatetrenone. A total of 18 consecutive patients newly diagnosed with MDS-RA were randomized to receive either 45 mg of oral menatetrenone (group 1) or no menatetrenone (group 2). Administration of menatetrenone was well tolerated. Of the nine patients in group 1 (56%), five improved with menatetrenone treatment while only one (11%) of the group 2 patients improved. Three patients (33%) showed a major response in absolute neutrophil count (ANC), two (22%) showed a major response in hemoglobin concentration, and two of the nine (22%) showed a major response in platelet count. The ANC of group 1 patients rose after treatment, while that of group 2 patients decreased slightly at follow-up after 16 weeks ( p=0.03). Significant improvement was also seen in final platelet count ( p=0.01), but not in hemoglobin concentration. Given the absence of toxicity, menatetrenone can be recommended for all patients with MDS-RA.

Decreased plasma activity of antithrombin or protein C is not due to consumption coagulopathy in septic patients with disseminated intravascular coagulation

We investigated whether depressed plasma antithrombin and protein C activity, considered as a specific finding of disseminated intravascular coagulation (DIC), is due to consumption coagulopathy in septic patients with DIC. An analysis of hemostatic parameters was performed in 139 septic patients (68 with DIC and 71 without DIC). Plasma activity of antithrombin and protein C tended to be significantly decreased in septic patients with DIC but not in those without DIC (p < 0.001). However, when the septic patients were classified into three groups according to the albumin (or choline esterase) level, no significant differences in antithrombin activity or protein C activity were observed between the patients with and without DIC in any of the subgroups. Notably, neither the plasma activity of antithrombin nor protein C was decreased even in septic patients with DIC who had normal plasma levels of albumin (or choline esterase). No significant correlation was observed between plasma levels of thrombin-antithrombin complex (TAT) and antithrombin activity, or between plasma levels of TAT and protein C activity either in septic patients with DIC or without DIC. It is reasonable to conclude that the markedly reduced plasma activity of antithrombin and protein C is not due to consumption coagulopathy in septic patients with DIC.

[Low dose melphalan therapy was effective in an elderly patient with MDS-AML]

An 80-year-old man with MDS-refractory anemia (RA) suffered transformation to a leukemic state after 18 months. The karyotype of the bone marrow cells was 47, XY, +8 in 8 cells among 20 dividing cells analyzed. Combination therapy of 150 micrograms of granulocyte colony-stimulating factor (G-CSF) and 250 mg of cytarabine ocfosfate (SPAC) for 3 weeks had no beneficial effect. Then, the patient was subjected to low-dose (2 mg daily) melphalan therapy. Gradual and concurrent improvement in anemia, thrombocytopenia, and neutropenia occurred, and the patient became free of transfusions at 2 weeks after the treatment began. Since then, his performance status has improved from grade 4 on his diagnosis of AML to grade 2. Cytogenetic analysis was normal in all 20 dividing cells in the bone marrow examination and melphalan had no adverse effect. Recently, several reports of low dose chemotherapy for elderly patients or high risk leukemia have been described, and have sustained for the QOL therapy. In the present case, low-dose melphalan therapy was effective and, moreover the abnormal karyotype of trisomy eight had disappeared.

Elevated levels of free tissue factor pathway inhibitor antigen in cases of disseminated intravascular coagulation caused by various underlying diseases

Tissue factor pathway inhibitor (TFPI) is primarily synthesized by vascular endothelial cells and is found in vivo in association with endothelial cells, lipoproteins, or in free form. Free TFPI is the most potent and important type, because it is released from endothelial cells following an injection of heparin, or as a result of pathological stimuli. In order to study the role of TFPI in disease, the concentration of free form TFPI was measured in the plasma of 114 patients suffering from disseminated intravascular coagulation (DIC), as the result of several underlying diseases. Plasma antigen levels of free TFPI were significantly higher even in those patients not exhibiting DIC than in normal healthy subjects. These levels were even higher among patients exhibiting DIC, especially those with acute promyelocytic leukemia or cancer, receiving continuous heparin drip infusions. A significant correlation was observed between the plasma antigen levels of free form TFPI and those of fibrin/fibrinogen degradation products, and free form TFPI and plasmin inhibitor complex (r = 0.428, P < 0.0001 and r = 0.329, P < 0.0001, respectively) among 114 DIC patients. There were no significant differences between the plasma levels of free TFPI in DIC patients with or without multiple organ failure. It has been suggested that the plasma levels of free TFPI are closely related to the levels of fibrinolysis occurring in DIC patients, although further study is required to clarify the degree to which TFPI is expressed by endothelial cells during DIC.

Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg x kg(-1) x min(-1)) in 8 WHHL rabbits (13.8+/-0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml x min(-1) x g(-1)) did not differ significantly between control and WHHL groups both at baseline (3.67+/-0.72 vs 4.26+/-1.12 ml x min(-1) x g(-1), p=NS) and with adenosine (7.92+/-2.00 vs 9.27+/-2.91 ml x min(-1) x g(-1), p=NS), nor did coronary flow reserve (2.16+/-0.37 vs 2.18+/-0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model.

Orbital T-cell lymphoma in a multiple myeloma patient

PURPOSE

To report an 82-year-old woman with multiple myeloma who developed an orbital T-cell lymphoma concomitantly.

METHODS

The patient presented with left upper eyelid swelling. Magnetic resonance imaging demonstrated an orbital mass compressing the eyeball. The mass was excised for diagnostic purposes and orbital decompression.

RESULTS

Histopathologic and immunohistochemical evaluation identified the mass as a T-cell lymphoma. The disease progressed rapidly despite chemotherapy.

CONCLUSIONS

Orbital T-cell lymphoma is rare and we are unaware of previous reports of orbital T-cell lymphoma in patients with multiple myeloma.

Induction of autologous graft-versus-host disease with cyclosporin A after peripheral blood stem cell transplantation: analysis of factors affecting induction

BACKGROUND

Induction of autologous graft-versus-host disease after peripheral blood stem cell transplantation has not been studied well.

OBJECTIVE

The purpose of this study was to analyze the factors that affect the development of autologous graft-versus-host disease.

METHODS

Nineteen patients with non-Hodgkin's lymphoma underwent peripheral blood stem cell transplantation followed by the administration of cyclosporin A for 28 days (group A) or 21 days (group B) and IFN-gamma.

RESULTS

Autologous graft-versus-host disease failed to develop in the any of the group A patients, who did not receive total body irradiation for conditioning and underwent the transplantation with unmanipulated peripheral blood stem cells, although cytotoxic activity against autologous lymphocytes was detectable in peripheral blood mononuclear cells obtained from all of them after the transplantation. Autologous graft-versus-host disease developed in 2 of 4 patients in group A who received enriched CD34(+) cells and in 7 of 11 patients who underwent conditioning with total body irradiation. Maculopapular erythema that was compatible with graft-versus-host disease developed on days 19 to 27 after the transplantation in these patients and resolved after 3 to 9 days without treatment.

CONCLUSIONS

Either the depletion of regulatory cells from the graft by enrichment of CD34(+) cells or the abolition of the autoregulation by including total body irradiation in the conditioning regimen may be effective in inducing autologous graft-versus-host disease after peripheral blood stem cell transplantation. Three weeks of cyclosporin A therapy appears to be sufficient to induce autologous graft-versus-host disease in recipients of peripheral blood stem cells.

Successful treatment of B-cell lymphoma associated with hemophagocytic syndrome using autologous peripheral blood CD34 positive cell transplantation followed by induction of autologous graft-versus-host disease

A 56-year-old man who presented with persistent high fever and abdominal pain was diagnosed as having a B-cell lymphoma associated with hemophagocytic syndrome (B-LAHS). As post-remission therapy, the patient was treated with high-dose chemoradiotherapy followed by infusion of autologous CD34+ cells that had been isolated from the peripheral blood buffy coat. Cyclosporin and interferon (IFN)-gamma were administered to induce autologous graft-versus-host disease (GVHD). Hematopoietic recovery promptly occurred and skin GVHD developed on day 26 after CD34+ cell transplantation. The patient has been in complete remission without therapy for 20 months since transplant. Autologous CD34+ cell transplantation in combination with induction of autologous GVHD may be efficacious in obtaining a cure for B-LAHS.

Uptakes and images of 38K in rabbit heart, kidney, and brain

The purpose of this study was to evaluate the kinetics and image quality of positron-emitting 38K (half-life, 7.6 min) and high-resolution small-animal PET in the heart, kidney, and brain of rabbits.

METHODS

Studies were performed with 18 closed-chest anesthetized rabbits at baseline and during infusions of adenosine (0.2 mg/kg/min) and propranolol (0.5-1.0 mg/kg intravenously) using high-resolution small-animal PET. 38K was injected intravenously and dynamic PET imaging of the heart, kidney, or brain was performed for 3 min. Colored microspheres were injected into the left ventricle to measure organ blood flow. Arterial blood was withdrawn directly from the femoral artery, and, after the animals were killed, 38K activities in each organ were measured directly with a well counter. Uptake of 38K was calculated by dividing the 38K activities in each organ by the integral of the input function. The extraction fraction of 38K was estimated by dividing the uptake of 38K in each organ by the organ blood flow, measured by microspheres.

RESULTS

The left ventricular myocardium and kidney were clearly visualized, but there was no visual 38K uptake in the brain. For the heart, kidney, and brain, respectively, average blood flow was 2.91 +/- 1.29, 5.49 +/- 0.71, and 0.57 +/- 0.11 mL/min/g, and the extraction fraction of 38K at baseline was 0.55 +/- 0.13, 0.48 +/- 0.13, and 0.022 +/- 0004. The Renkin-Crone model fit the relation between myocardial extraction and flow under a wide range of myocardial blood flow (r = 0.89).

CONCLUSION

38K is a suitable tracer for noninvasively showing the potassium kinetics of the heart, kidney, and brain by PET imaging.

Cytotoxicity against lymphoblastoid cells mediated by a T-cell clone from an aplastic anaemia patient: role of CD59 on target cells

In an attempt to elucidate the pathogenic role of a CD4+ cytotoxic T-cell clone NT4.2 isolated from the bone marrow of a patient with cyclosporine-dependent aplastic anaemia, we characterized the T-cell clone as well as its cytotoxicity against an autologous Epstein-Barr (EB) virus-transformed B-lymphoblastoid cell line (LCL). NT4.2 expressed BV21+ BJ2.7+ with a complementarity-determining region (CDR) 3 motif of SQGQGEVEQY which was homologous to that of a T-cell clone isolated from a patient with connective tissue disease. NT4.2 started to lyse LCL cells within 2 h and exerted maximal cytotoxicity within 3 h of incubation. The cytotoxicity required the presence of divalent cations and was not associated with DNA fragmentation of the target cells. Anti-CD59 monoclonal antibodies (MoAb) blocked the cytotoxicity to the same degree as anti-CD3, HLA-DR or CD2 mAb. Flow cytometric analysis of the peripheral blood of this patient during remission after cyclosporine therapy revealed 1.7% of granulocytes to be deficient in CD59. These findings indicate that NT4.2 exerts its cytotoxicity through a perforin-mediated pathway, not a Fas/Fas ligand-dependent pathway, and that haemopoietic stem cells lacking CD59 may evade cytotoxic T lymphocytes, leading to the in vivo expansion of a paroxysmal nocturnal haemoglobinuria clone.

Cone-beam CT angiography of the thorax: an experimental study

The authors recently developed a cone-beam computed tomography (CT) scanner and this report presents their evaluation of its potential for thoracic vascular imaging. An X-ray tube and a video-fluoroscopic system were rotated around the objects and 360 projected images were collected in a 12-s scan. Each image was digitized and a 3 dimensional (D) image (256x256x256 voxel volume with a voxel dimension of 0.9x0.9x0.9 mm) was reconstructed. Two different 3D-CT angiographies were investigated in 2 pigs: right atriography and thoracic aortography. Each pig was anesthetized, mechanically ventilated and positioned within the scanner. Contrast agent was infused through the right atrium or the aortic root at a rate of 3 ml/s during the scan. The right atriography scan clearly delineated the anatomy of the pulmonary artery, heart chambers and thoracic aorta. The thoracic aortography scan also clearly delineated the aortic anatomy including the internal thoracic and intercostal arteries. In conclusion, cone-beam CT angiography is potentially useful for thoracic vascular imaging.

High inducibility of heat shock protein 72 (hsp72) in peripheral blood mononuclear cells of aplastic anaemia patients: a reliable marker of immune-mediated aplastic anaemia responsive to cyclosporine therapy

To better characterize immunologic aberrations in aplastic anaemia (AA), we examined peripheral blood mononuclear cells (PBMC) of 67 patients with AA and other patients with various haematological diseases for the expression of heat shock protein 72 (hsp72), which is inducible in lymphocytes by various stressors including antigenic stimulation. When freshly obtained PBMC were examined using flow cytometry, the proportion of cells expressing hsp72 in cytoplasm was significantly higher in allogeneic marrow transplant recipients (22 +/- 15%, mean +/-standard deviation (SD)) and AA patients (17 +/- 21%) than in normal individuals (6 +/- 3%). When PBMC were tested after heat treatment, only the proportion of hsp72+ cells of AA patients (37 +/- 30%) was significantly higher than that of the normal control (17 +/- 11%). Dual fluorescence analysis of the PBMC revealed that the majority of hsp72+ cells was CD3+. For 28 untreated AA patients, the proportion of hsp72+ cells in those who later responded to cyclosporine (CyA) (62 +/- 24%) was higher than that in non-responders (19 +/- 13%). Immunoblotting analysis revealed predominant expression of hsp72 in T cells. These findings indicate that high inducibility of hsp72 in PBMC by heat treatment is an immunologic aberration characteristic of CyA-responsive AA and that this simple test may be useful for identifying a subset of AA patients responsive to immunosuppressive therapy.

Characterization of T-cell repertoire of the bone marrow in immune-mediated aplastic anemia: evidence for the involvement of antigen-driven T-cell response in cyclosporine-dependent aplastic anemia

To determine whether the antigen-driven T-cell response is involved in the pathogenesis of aplastic anemia (AA), we examined the complementarity-determining region 3 (CDR3) size distribution of T-cell receptor (TCR) beta-chain (BV) subfamilies in the bone marrow (BM) of untreated AA patients. AA patients who did not respond to immunosuppressive therapy and those who obtained unmaintained remission early after cyclosporine (CyA) or antithymocyte globulin (ATG) therapy exhibited essentially a normal CDR3 size pattern. In contrast, five patients who needed continuous administration of CyA to maintain remission exhibited a skewed CDR3 size pattern in a number (>40%) of BV subfamilies suggestive of clonal predominance. The skewing of CDR3 size distribution became less pronounced in one of the CyA-dependent patients when the patient achieved unmaintained remission after a 4-year therapy with CyA, whereas it persisted longer than 7 years in the other patient requiring maintenance therapy. Sequencing of BV15 cDNA for which the CDR3 size pattern exhibited apparent clonal predominance in all CyA-dependent patients showed high homology of the amino acid sequence of the CDR3 between two different patients. These findings indicate that antigen-driven expansion of T cells is involved in the pathogenesis of AA characterized by CyA-dependent recovery of hematopoiesis.

Impaired response of granulocyte-committed progenitor cells to stem cell factor and granulocyte colony-stimulating factor in human cyclic neutropenia

Although cyclic neutropenia (CN) has been the subject of extensive studies due to its striking clinical picture, the abnormality of hematopoietic progenitor cells in patients with CN has been poorly defined. We studied the sensitivity of progenitor cells of a CN patient to colony-stimulating factors (CSF) including G-CSF, interleukin-3 (IL-3), and stem cell factor (SCF). Peripheral blood progenitor cells of the patient required a significantly higher dose of G-CSF to give rise to colonies than those of normal controls. While the presence of SCF enhanced the number of G-CSF-induced colonies regardless of the concentration of G-CSF in normal controls, this synergistic effect of SCF was limited to the high concentration of G-CSF in the patient, indicating that the abnormality in hematopoiesis in CN involved more immature progenitor cells responsive to SCF.

Early establishment of hematopoietic chimerism following allogeneic peripheral blood stem cell transplantation in comparison with allogeneic bone marrow transplantation

To characterize the process of the establishment of complete chimerism after allogeneic peripheral blood stem cell transplantation (allo-PBSCT), we determined the origin of leukocytes in peripheral blood (PB) obtained from 23 patients in the very early period after allo-PBSCT using amplification of mini- or microsatellite regions of genomic DNA. Donor-specific alleles were amplified from the PB obtained at day 8 post-transplant for 19 allo-PBSCT patients. Among the 19 patients, 12 showed only donor-specific alleles (complete chimerism) while 7 did both donor and host-specific alleles (mixed chimerism). Although donor specific alleles were amplified in 10 of 12 patients who received allogeneic bone marrow transplantation (allo-BMT) similarly to allo-PBSCT, all of these ten showed mixed chimerism. When the chimeric state was examined in PB samples obtained serially at 2-3-day intervals post-transplant, host-specific alleles in allo-PBSCT patients were not detectable in the PB much earlier than those in allo-BMT patients. These findings indicate that the appearance of donor-derived cells associated with the disappearance of host-derived cells in the circulation occurs earlier after allo-PBSCT as compared with allo-BMT, leading to the rapid establishment of complete chimerism.

Successful therapy of myelodysplastic syndrome with menatetrenone, a vitamin K2 analog

Although vitamin K2 is an inducer of the in vitro differentiation of myeloid leukemic cell lines, its clinical efficacy in the treatment of myelodysplastic syndrome (MDS) is unclear. We administered a vitamin K2 analog, menatetrenone, at 45 mg daily to an 80-year-old woman with MDS (refractory anemia) heavily dependent on red-cell transfusions. The patient's pancytopenia gradually improved, and she became transfusion-independent after 14 months. Pancytopenia recurred when menatetrenone was discontinued but recovered again with readministration. Administration of menatetrenone at a dose effective in improving osteoporosis may also be useful in restoring hematopoiesis in MDS patients, possibly by way of inducing differentiation.

Administration of G-CSF to normal individuals diminishes L-selectin+ T cells in the peripheral blood that respond better to alloantigen stimulation than L-selectin- T cells

To determine whether administration of G-CSF induces phenotypic or functional changes in T cells, we examined peripheral blood T cells from normal individuals receiving G-CSF for activation antigen and adhesion molecule expression before and after G-CSF administration. G-CSF (10 microg/kg/day) was administered subcutaneously to 14 normal individuals for 3-5 days and their PBMC were serially analyzed with monoclonal Ab (mAb) directed to HLA-DR, CD45RO, CD45RA, CD25, CD122, CD95, CD11a, CD49d, CD44 and CD62L (L-selectin) coupled with anti-CD3 mAb. Among T cells positive for these antigens, only the proportion of T cells expressing L-selectin significantly decreased from 68% to 37% after 3-day G-CSF administration. When peripheral blood CD3+ T cells obtained before and after G-CSF administration were sorted into two populations depending on the expression of L-selectin and tested for their proliferative response to allogeneic B cells, the reactivity of L-selectin- cells to alloantigen stimulation was consistently lower than that of L-selectin+ cells regardless of the exposure to G-CSF. The decrease in the relative number of L-selectin+ cells induced by G-CSF administration may contribute to the unexpectedly low incidence of severe acute GVHD after allogeneic PBSC transplantation.

High-resolution cardiac PET in rabbits: imaging and quantitation of myocardial blood flow

A high-resolution PET system for small animals was tested for its applicability to the investigation of regional myocardial blood flow (MBF) in rabbits.

METHODS

Nineteen measurements were performed in 10 closed-chest anesthetized rabbits at baseline and during infusions of adenosine (0.2 mg/kg/min) and propranolol (0.20-1.20 mg slow infusion) to obtain a wide range of MBF. Myocardial blood flow was assessed both by dynamic 13N-ammonia PET and by colored microspheres. Blood was withdrawn directly from the femoral artery, and arterial 13N activity was measured by coincidence type gamma detection system for the input function. Nitrogen-13 myocardial uptake was calculated by dividing the myocardial 13N activity by the integral value of the input function.

RESULTS

Three or four contiguous cross-sectional myocardial images were obtained after 13N-ammonia injection. The left ventricular wall and cardiac cavity were clearly visualized. Moreover, initial passage of the tracer through the heart was obtained with serial 10-sec PET images. Nitrogen-13 myocardial uptake correlated well with flow measured with microspheres (r = 0.88).

CONCLUSION

Our cardiac PET system can be used for in vivo imaging and quantitation of MBF in small animals and may play an important role in the future study of animal models of cardiovascular diseases.

CD20-positive T-cell chronic lymphocytic leukaemia

Although CD20 is considered to be a representative marker for B lymphocytes, the antigen is weakly expressed on a small subset of normal T lymphocytes. A 60-year-old man developed pancytopenia and hepatosplenomegaly due to clonal proliferation of atypical lymphocytes that were weakly positive for CD20. The leukaemic cells were also positive for T-cell antigens such as CD2, CD3, CD5, CD7, CD8 and T-cell receptor (TCR) Vbeta8 and for activation antigens such as CD38 and HLA-DR, but were negative for CD19, CD21, CD22, CD25. Southern blot analysis revealed rearrangement of the TCR-beta gene and a germline configuration of the immunoglobulin heavy chain gene. This is the first report of a case of clonal expansion of CD20dim T lymphocytes.

Simple and Patlak models for myocardial blood flow measurements with nitrogen-13-ammonia and PET in humans

The Simple and Patlak models for estimating myocardial blood flow with 13N-ammonia have become attractive for clinical applications with PET because of their simplicity and ease of implementation. However, these models are sensitive to factors such as the data acquisition times and data integration times, which can cause errors in the estimation of myocardial blood flow, as demonstrated in this study. Limiting the application of these models to specific conditions can minimize the errors.

METHODS

Dynamic PET images of the uptake of 13N-ammonia in the heart were obtained in seven humans under rest and dipyridamole stress. Myocardial blood flow was estimated using the Simple and Patlak models for different data acquisition times and data integration times. Blood flow values were compared to flow values computed with the two-compartment model as a reference.

RESULTS

Blood flow values calculated with the Simple and Patlak models during the first 2 min of data acquisition were closely correlated to the two-compartment model values. Longer acquisition times resulted in significant underestimation of blood flow for the Simple model. Long integration times of greater than 60 sec also resulted in significant underestimation of blood flow for both models.

CONCLUSION

The Simple and Patlak models produce estimates of myocardial blood flow that are well correlated with the two-compartment model estimated blood flows for the integration time of 60 sec from 60 to 120 sec postinjection. Because of the errors associated with longer data acquisition times and longer integration times, use of these models should be limited to a well-documented data acquisition paradigm.

Successful treatment of Epstein-Barr virus-associated natural killer cell large granular lymphocytic leukaemia using allogeneic peripheral blood stem cell transplantation

We report a case of natural killer cell large granular lymphocytic (NK-LGL) leukaemia successfully treated with allogeneic peripheral blood stem cell transplantation (allo-PBSCT). The peripheral blood (PB) revealed an abnormal expansion of LGL that were CD3-, CD16- and CD56+, and had natural killer activity. In situ EBER-1 hybridization of the PB mononuclear cells showed the presence of Epstein-Barr virus (EBV) in the LGL as well as in lymphocytes infiltrating the tonsils and colon. Southern blotting with an EBV-terminal repetitive sequence probe demonstrated clonal proliferation of EBV+ cells. The patient received allo-PBSCT from his HLA-matched sister with a conditioning regimen involving the use of cyclophosphamide and fractionated total body irradiation. The patient promptly recovered trilineage haematopoiesis without graft-versus-host disease, and has been in complete remission without therapy for 10 months since allo-PBSCT, suggesting that allo-PBSCT could eradicate the NK-LGL leukaemic cells.

Castability of a commercial castable glass ceramics

This study was carried out to determine the design and thickness of the cervical margin of a castable ceramic restoration from the point of view of its castability. Castability of castable ceramics was lower compared to Ag-Pd-Au and Co-Cr alloy with the use of the mesh pattern and rod pattern test (p < 0.05). It was more dependent on the pattern thickness than alloys (p < 0.05), and perfect reproducibility with non-measurable variability could be estimated to reach 1.0 mm thickness of the original pattern (p < 0.001). Marginal shape was certainly more reproducible in a right angle shoulder than in 30, or 45 degree bevels (p < 0.05). From these results, it is suggested that a right angle shoulder margin with 1.0 mm thickness is more suitable to castable glass ceramic restoration than any other design.

Induction of autocytotoxic T cells with cyclosporine and interferon-gamma for patients with non-Hodgkin's lymphoma after transplantation of peripheral blood stem cells

BACKGROUND

Autologous graft-versus-host disease is inducible after autologous bone marrow transplantation by means of administration of cyclosporine.

OBJECTIVE

This study was performed to investigate the inducibility of autologous graft-versus-host disease after transplantation of peripheral blood stem cells (PBSCs).

METHODS

Two patients with non-Hodgkin's lymphoma in remission underwent PBSC transplantation followed by administration of cyclosporine and low-dose interferon-gamma.

RESULTS

Although autologous graft-versus-host disease did not develop in either patient, T lymphocytes with cytotoxic activity against autologous lymphocytes appeared transiently in the early posttransplant period. Such autocytotoxic lymphocytes were not detectable in another patient who underwent PBSC transplantation who did not receive cyclosporine and interferon-gamma. When CD4+ and CD8+ cells were sorted from the peripheral blood mononuclear cells of one of the two patients and tested for cytotoxicity against autologous lymphocytes, only CD8+ cells exhibited cytotoxic activity.

CONCLUSIONS

The results indicate that administration of cyclosporine and interferon-gamma after PBSC transplantation can induce autocytotoxic CD8+ T cells, even though it may not produce autologous graft-versus-host disease. It is unclear whether induction of such autocytotoxic T cells among patients with non-Hodgkin's lymphoma who undergo PBSC transplantation has any antilymphoma effect.

Inhibition of immature erythroid progenitor cell proliferation by macrophage inflammatory protein-1alpha by interacting mainly with a C-C chemokine receptor, CCR1

Several lines of evidence indicate that macrophage inflammatory protein-1alpha (MIP-1alpha) modulates the proliferation of hematopoietic progenitor cells, depending on their maturational stages. To clarify the mechanisms for the modulation of hematopoiesis by this chemokine, we examined the expression of a receptor for MIP-1alpha, CCR1, on bone marrow cells of normal individuals using a specific antibody and explored the effects of MIP-1alpha on in vitro erythropoiesis driven by stem cell factor (SCF) and erythropoietin (Epo). CCR1 was expressed on glycophorin A-positive erythroblasts in addition to lymphocytes and granulocytes. CCR1+ cells, isolated from bone marrow mononuclear cells (BMMNCs) using a cell sorter, comprised virtually all erythroid progenitor cells in the BMMNCs. Moreover, MIP-1alpha inhibited, in a dose-dependent manner, colony formation by burst-forming unit-erythroid (BFU-E), but not by colony forming unit-erythroid (CFU-E), in a methylcellulose culture of purified human CD34+ bone marrow cells. Although reverse-transcription polymerase chain reaction (RT-PCR) showed the presence of CCR1, CCR4, and CCR5 transcripts in CD34+ cells in BM, anti-CCR1 antibodies significantly abrogated the inhibitory effects of MIP-1alpha on BFU-E formation both in a methylcellulose culture and in a single cell proliferation assay of purified CD34+ cells. Although the contribution of CCR4 or CCR5 cannot be completely excluded, these results suggest that MIP-1alpha-mediated suppression of the proliferation of immature, but not mature erythroid progenitor cells, is largely mediated by CCR1 expressed on these progenitor cells.