Lymphatic vascular density and lymphangiogenesis during tumour progression of carcinoma ex pleomorphic adenoma.

AIMS: To assess lymphatic vascular density (LVD) and lymph vessel endothelial proliferation in a series of carcinoma ex pleomorphic adenoma (CXPA) that represents the tumour in the different carcinogenesis phases and tumour progression. METHODS: In 8 cases of early CXPA (intracapsular and minimally invasive tumours), 8 of advanced CXPA (widely invasive tumours) and 10 of pleomorphic adenoma (PA) without malignant transformation, lymphatic vessels and proliferating cells were detected using the antibodies D2-40 and Ki-67 respectively. RESULTS: Comparing early tumours with advanced ones, LVD was not significantly different at the tumour margin. In contrast, regarding intratumoural lymphatics, PA without malignant transformation and early CXPA contained rare, if any, lymph vessels, whereas in widely invasive carcinomas they were more numerous. However, neither intratumoural nor peritumoural LVD were increased in comparison to adjacent normal salivary gland tissue. In no case did dual immunohistochemistry using D2-40 and the cell proliferation marker Ki-67 reveal the existence of proliferating lymphatics. Carcinomatous emboli were found in peritumoural as well as in intratumoural lymphatics only in advanced CXPA without myoepithelial differentiation. CONCLUSION: In CXPA, the lymphatic network is mainly composed of pre-existing lymphatics which are rare in tumours that have not infiltrated outside the confines of the original PA. In the widely invasive CXPA, intratumoural as well as peritumoural lymphatics are a conduit for carcinoma cells, but in carcinomas with myoepithelial differentiation, the neoplastic cells seem to have a lower invasion capacity.

Cytotoxic chemotherapy preceding apheresis of peripheral blood progenitor cells can affect the early reconstitution phase of naive T cells after autologous transplantation.

Transient T cell immunodeficiency is a common complication following hematopoietic stem cell transplantation. In breast cancer patients transplanted with autologous peripheral blood progenitor cells (PBPC) harvested after cytotoxic treatment with either cyclophosphamide or epirubicin plus paclitaxel, we evaluated T cells infused in grafts and in peripheral blood during the early reconstitution phase. We found that PBPC grafts harvested after treatment with epirubicin plus paclitaxel contained substantially larger numbers of T cells with less altered composition than after cyclophosphamide. Three months after high-dose cytotoxic chemotherapy, the numbers and the kinetics of circulating naive T cells, but not of memory and CD28- T cells, correlated positively with the number of naive T cells infused PBPC grafts. Finally, retrospective analysis of two cohorts of patients transplanted in different clinical settings with PBPC grafts harvested following cyclophosphamide or epirubicin plus paclitaxel showed apparently different susceptibilities to develop endogenous varicella zoster virus reactivation in the first year after high-dose cytotoxic chemotherapy. On the whole, these data indicate that number and composition of T cells in PBPC grafts vary according to the former cytotoxic therapy, and suggest that autologous transfer of T cells may accelerate the early T cell reconstitution phase and possibly ameliorate immune competence in patients rendered lymphopenic by high-dose chemotherapy.

Primitive haematopoietic progenitors in the blood of patients with sickle cell disease appear to be endogenously mobilized.

To investigate whether haematopoietic stem cells in patients with sickle cell (SS) disease might be altered, we examined the number and cycling status of 5-week long-term culture-initiating cells (LTC-ICs) and in vitro multilineage colony-forming cells (CFCs) present in the blood of a large and clinically diverse group of SS patients. The concentrations of both of these cell types per ml of blood varied over a wide range in individual patients, but, on average, were significantly elevated above normal values ( approximately sevenfold and 15-fold respectively) and to an even greater extent than the lineage-restricted CFCs in the same samples. Wide variations in the concentration of circulating progenitors, particularly the LTC-ICs, were also seen over time (in concert with changes in the white blood cell count) in SS patients. [3H]-Thymidine suicide assays showed most of the CFCs and LTC-ICs in SS blood to be quiescent like their counterparts in normal blood. However, by comparison with historical data, the SS progenitors could be recruited into the cycle more quickly (i.e. within 2 vs. 3 d), thus showing the same kinetics of activation exhibited by 'mobilized' progenitors from patients given chemotherapy and exogenous growth factors. Taken together, these findings implicate previously documented increases in endogenous Steel factor, interleukin 3 and granulocyte-macrophage colony-stimulating factor levels in SS patients in the establishment of a chronically mobilized progenitor phenotype.

Four-day infusion of fluorouracil plus vinorelbine as salvage treatment of heavily pretreated metastatic breast cancer.

AIMS: Anthracyclines-taxanes containing regimens are widely used for breast cancer treatment both in neoadjuvant-adjuvant setting and in metastatic disease. Recently high-dose chemotherapy (HDC) with autologous stem cell support has been introduced as adjuvant treatment for high-risk primary breast cancer and for selected subsets of women with metastatic disease. Therefore, salvage treatment for previously treated patients with progressive disease becomes even more problematic. A regimen of continuous infusion of fluorouracil (FU) and vinorelbine (VNR) has been evaluated in heavily pretreated metastatic breast cancer patients. PATIENTS AND METHODS: Forty-eight women, median age 52 years, with previously treated breast cancer entered the study. All but one received more than one line of prior systemic chemotherapy for metastatic disease. Furthermore 14 women had undergone HDC with peripheral blood progenitor cells transplantation in adjuvant setting (6 pts), or metastatic disease (8 pts). Treatment consisted of four-day infusion of FU (1000 mg/m2/day) plus VNR (20 mg/m2/i.v. day 1 and 5), recycled every 3 weeks for a total of six courses. Drugs administration was discontinued for G4 toxicity, tumor progression or patient's refusal. RESULTS: Twenty PR and four CR for an overall response rate of 50% (95%C.I. 36-64%) were recorded. The therapeutic efficacy of the tested regimen was documented both in patients unresponsive to previous anthracyclines-taxanes combinations and in those relapsing after HDC. The median duration of response was 9 months and median survival 16 months. One third of patients experienced Grade-3 stomatitis-mucositis, hematological toxicity was mild and no cardiac toxicity was observed. Twenty-five women (52%) suffered from infusion-related phlebitis (in half of patients a central venous device was necessary at some point of the treatment program). CONCLUSIONS: The combination of FU infusion and VNR i.v. is an effective salvage treatment for heavily pretreated metastatic breast cancer patients, and may represent a valid alternative when other cytotoxic regimens are not feasible.

Negative immunomagnetic purging of peripheral blood stem cell harvests from breast carcinoma patients reduces tumor cell contamination while not affecting hematopoietic recovery.

BACKGROUND: Because tumor contamination of hematopoietic stem cell grafts may influence the outcome in breast carcinoma (BC) patients undergoing high dose chemotherapy (HDC), several ex vivo procedures for the purging of autologous harvests have been investigated. The authors studied the presence of epithelial tumor cells and the growth of hematopoietic progenitors in peripheral blood stem cell (PBSC) collections from patients with metastatic breast carcinoma before and after a purging procedure performed by a negative immunomagnetic BC cell separation. METHODS: Eighteen patients entered the study. Tumor contamination was assessed by conventional immunocytochemistry (ICC) and by a liquid culture assay developed in the study laboratory. Committed and more primitive hematopoietic progenitors were quantitated before and after the negative selection. Ten patients received HDC with purged PBSC support. RESULTS: Before purging, 4 of 18 PBSC collections were found to be contaminated by liquid culture; among these samples, only 1 was positive by ICC. Three of the four positive collections, including the ICC positive sample, became negative after immunomagnetic selection whereas BC cells still were present after the procedure in one harvest. A high recovery of both primitive and mature hematopoietic progenitors was found after the purging procedure. Patients receiving purged PBSC after myeloablation had a prompt and complete hematopoietic reconstitution, and no graft failure was observed at a median follow-up of 1 year. CONCLUSIONS: The preliminary results of the current study suggest that negative selection of BC cells is able to purge PBSC effectively while having no apparent affect on hematopoietic progenitor recovery in vitro and in vivo.

Transfusion of platelet concentrates cryopreserved with ThromboSol plus low-dose dimethylsulphoxide in patients with severe thrombocytopenia: a pilot study.

We have recently reported the possibility of supporting the phase of severe thrombocytopenia after high-dose chemotherapy (HDC) and stem cell transplantation using 5% dimethylsulphoxide (DMSO)-cryopreserved autologous platelet concentrates (PCs). The aim of the present study was to evaluate the therapeutic potential of ThromboSol (a recently developed platelet storage solution) plus PCs cryopreserved in 2% DMSO in patients undergoing myeloablative chemotherapy and autologous transplantation. PCs were collected from 14 women with breast cancer by a single plateletapheresis and cryopreserved in ThromboSol/2% DMSO by either direct insertion in a -80 degrees C freezer or in liquid nitrogen after computer-controlled rate (CR) freezing. When required, PCs were thawed, centrifuged to remove the cryoprotectants and transfused. In vitro studies on thawed platelets showed loss of epitopes of surface glycoproteins and a marked reduction of functional activity compared with fresh platelets. Transfusion of CR-frozen PCs was associated with a mean 1 h corrected count increment (CCI) of 9.2 +/- 5.4 x 109/l and only one allogeneic PC was required in this group. In contrast, six out of seven patients required additional allogeneic transfusions in the -80 degrees C group (CCI = 2.7 +/- 1.4 x 109/l). ThromboSol-treated PCs have the ability to overcome thrombocytopenia if processed by a CR freezing protocol, but appear ineffective when frozen by direct placing at -80 degrees C.

Mitomycin C as an alternative to irradiation to inhibit the feeder layer growth in long-term culture assays.

BACKGROUND: Mitomycin C (MMC), an antitumoral antibiotic, has been described inhibiting the proliferation of different cell types in vitro. Since irradiation is commonly used to stop the cell growth of adherent cells in several experimental models, we aimed to define the optimal dose and incubation time of MMC capable of inhibiting the growth of murine fibroblasts, used as an adherent feeder layer in long-term hematopoietic culture assay. METHODS: M2 10B4 (both parental and engineered to produce human IL-3 and G-CSF) and Sl/Sl (engineered to produce human IL-3 and steel factor) murine fibroblast cell-lines, frequently used in LTC-IC assay, were incubated with increasing doses of MMC for either a short (3 h) or a long (16 h) period. The efficiency of MMC in stopping the cell growth was evaluated for 5 days following MMC removal. The effects of MMC treatment on human hematopoietic cells were studied using both LTC-IC and limiting dilution (CAFC) assays. RESULTS: The growth of M2 10B4 cells was stopped at 3 and 16 h in the presence of 20 microg/mL and 2 microg/mL of MMC, respectively while Sl/Sl fibroblasts required a lower dose of drug (2 and 0.2 microg/mL, respectively). No significant difference was found between the number of LTC-IC or CAFC obtained from cultures containing irradiated or MMC-treated feeder cells. DISCUSSION: MMC inhibits the growth of murine fibroblasts used as adherent feeder cells in long-term culture assays, without interfering with the subsequent growth of co-cultured hemopoietic cells. Different cell types might present a different sensitivity to MMC and therefore a dose-response curve to MMC has to be obtained for each cell type of interest.

Minimal tumor contamination of hematopoietic harvests from breast cancer patients can be easily detected by liquid culture assay.

BACKGROUND: Recurrence after PBSC transplantation in breast cancer (BC) patients may be related to the reinfusion of tumor cells contaminating the graft. We have developed a liquid culture (LC) method for the identification of viable epithelial tumor cells in PBSC collections. METHODS: Mononuclear fraction from PBSC harvests of BC patients undergoing high dose chemotherapy (HDC) (adjuvant setting n = 60, metastatic disease n = 30) were seeded in petri dishes containing round cover slips. Cells were cultured for 3 weeks, then cover slips were stained with the pan-cytokeratin A45-B/B3 mAb and scored under a light microscope. Samples were considered positive when more than one adherent cell or a cluster of cells staining bright red was present. Results were compared with those obtained on cytospins prepared directly from the PBSC harvest. Specificity of the method was tested on lymphoma patients, collections: all were negative. The sensitivity, evaluated by serial dilutions of CG5 BC cell line, was 1 epithelial cell in 10(6) mononuclear cells. RESULTS: The percentage of positivity was superimposable in the two groups (adjuvant 25%, metastatic 24%). However, a significantly higher proportion of positive samples from metastatic vs adjuvant patients has shown the presence of tumor clusters (86% vs 33%, p = 0.063). In 21% of all samples a discrepancy with the results obtained by immunocytochemical analysis (ICC) was found, mostly due to liquid-culture-positive/ICC-negative PBSCs. DISCUSSION: Our data suggest that LC assay may enhance the identification of viable disseminated epithelial tumor cells in PBSC grafts and might provide insights about their growth capacity.

Efficacy of epirubicin/paclitaxel combination in mobilizing large amounts of hematopoietic progenitor cells in patients with metastatic breast cancer showing optimal response to the same chemotherapy regimen.

BACKGROUND AND OBJECTIVE: Based on our preliminary experience, we have further evaluated the capacity of the paclitaxel/epirubicin combination (at the dose of 175 and 90 mg/m(2), respectively) plus G-CSF to mobilize hematopoietic progenitors into the circulation. DESIGN AND METHODS: The study was conducted in a homogeneous cohort of 25 stage IV breast cancer patients showing response to three cycles of the same chemotherapy regimen and who were included in a high-dose chemotherapy program. RESULTS: In most cases (68%) more than 5_10(6) CD34+ cells/kg b.w. (the threshold fixed in our study) were collected by a single leukapheresis, 28% and 4% of patients requiring 2 and 3 procedures, respectively. Based on the CD34+ cell count in the peripheral blood, most of the leukaphereses (53%) were performed on day 11 after chemotherapy. More than 50 CD34+ cells/mL along with a preleukapheresis WBC count between 10 and 20_10(9)/L predicted that only a single harvest would be required in 100% of cases. The evaluation of the clonogenic potential of collected cells showed that a large number of committed colony-forming cells (CFCs) and more primitive long-term culture-initiating cell (LTC-IC) hematopoietic progenitors were present in 20 harvests studied. INTERPRETATION AND CONCLUSIONS: These data demonstrate that the epirubicin/paclitaxel combination followed by G-CSF, besides being a very active regimen in MBC, is effective in releasing large amounts of progenitor cells into the circulation which can then be safely employed to support myeloablative regimens.

Poor outcome of patients with resectable breast cancer receiving adjuvant high-dose sequential chemotherapy following preoperative treatment.

BACKGROUND/OBJECTIVES: The prognosis of resectable high risk breast cancer (BC) patients (N+ > 10) is poor with a five-year disease-free survival (DFS) after standard adjuvant ADM/CMF chemotherapy (CT) of about 40%. An improvement in survival has been reported when high-dose chemotherapy with autologous stem cell support is given. It has been recently suggested that nodal status and the degree of pathological remission following preoperative CT administered in patients harbouring tumors larger than 3 cm represent the most important prognostic factors for DFS. Since no data are available regarding the impact of primary CT in the high dose CT adjuvant setting, we retrospectively evaluated the efficacy of administering megadoses of cytotoxic drugs with stem cell support in the subgroup of patients showing poor response to preoperative CT., PATIENTS AND METHODS: Fourteen women with high risk BC, N+ > 10 and tumor size > 3 cm following antracyclin-based primary CT, received high dose sequential chemotherapy (HDS). The median number of positive axillary nodes at surgery was 18 and tumor size was greater than 5 cm in 6 patients. HDS chemotherapy consisted of cyclophosphamide (7 gr/m2), methotrexate (8 gr/m2) plus vincristin (2 mg), 2 courses of carboplatin (360 mg/m2), and Thiotepa (600 mg/m2) plus L-PAM (160 mg/m2) as final myeloablative regimen requiring stem cell support. RESULTS: At a minimum follow up of 12 months (median 18 months, range 12-40) 5 patients remained disease free (36%) and 9 (64%) have relapsed (7 within the first 10 months). CONCLUSION: Our retrospective analysis suggests that BC patients showing poor response to primary CT might fail to achieve the benefits expected from high dose intensification.

Differences between normal and CML stem cells: potential targets for clinical exploitation.

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder in which there is a deregulated amplification of CML progenitors at intermediate stages of their differentiation along the myeloid, erythroid and megakaryocyte pathways. Such cell populations are routinely quantified using standard in vitro colony-forming cell (CFC) assays. The excessive production of leukemic CFC that is seen in most CML patients at diagnosis may be explained at least in part by their increased proliferative activity. An anomalous cycling behavior in vivo has also been found to extend to more primitive CML progenitor populations detectable as long-term culture-initiating cells (LTC-IC). Although the molecular basis of these changes in CML progenitor regulation is not fully understood at the level of the primitive CFC compartment, a selective inability of CML progenitors to be inhibited by certain -C-C-type chemokines has been demonstrated. Failure of the CML stem cell compartment to expand in vivo at the same rate as later progenitor cell types may be explained by their unique additional possession of an intrinsically upregulated probability of differentiation. Such a mechanism would be consistent with the observed loss of LTC-IC activity by CML cells incubated in vitro under conditions that sustain or expand normal LTC-IC populations. Initial clinical studies undertaken at our center established the feasibility of exploiting the differential behavior of primitive normal and CML cells in vitro as a potential purging strategy for reducing the leukemic stem cell content of CML marrow autografts. The results of a larger, second trial now in progress on a group of unselected patients are encouraging. Future studies of nonobese diabetic/severe-combined immunodeficiency mice engrafted with CML cells should provide another useful preclinical model for evaluating treatments that may more effectively eradicate the neoplastic clone in vivo.

Both cycling and noncycling primitive progenitors continue to be mobilized into the circulation during the leukapheresis of patients pretreated with chemotherapy and G-CSF.

Colony-forming cells (CFC) and long-term culture-initiating cells (LTC-IC) include a spectrum of progenitor types whose potential contributions to the haemopoietic recovery seen in patients transplanted with mobilized peripheral blood progenitor cells (PBPC) remains unclear. We evaluated both the number and cycling status of the circulating LTC-IC and CFC harvested from 12 patients treated with chemotherapy and G-CSF using a modified 6-week LTC-IC assay. The frequency of the LTC-IC and CFC in the mobilized PB samples were increased 45- and 750-fold, respectively. Interestingly, comparison of these values for PB samples, taken just prior to the start of the leukapheresis, with the progenitor content of the 3 h harvest, showed that, on average, the leukapheresis product contained 19 times more LTC-IC (P < 0.01) than had been detectable in the entire blood volume of the patients at the start of the collection, whereas the number of CFC collected was approximately the same as the number in the initial circulating pool of PBPC. Cycling studies showed many of the LTC-IC in the apheresis collections to be proliferating although not more so than in the steady-state marrow LTC-IC compartment (i.e. per cent kill of mobilized LTC-IC after 16 h in 3H-Tdr = 70 +/- 8%, n = 9). On the other hand, the majority of the CFC in the apheresis collections were initially quiescent (per cent kill after 16 h in 3H-Tdr = 37 +/- 6%, n = 12). These findings demonstrate the rapidity with which a primitive subset of LTC-IC may enter the circulation during the early phase of rebound haemopoiesis induced by chemotherapy plus G-CSF and provide evidence of differences in the mechanisms regulating LTC-IC and CFC mobilization.

Allogeneic hematopoietic stem cells from sources other than bone marrow: biological and technical aspects.

BACKGROUND AND OBJECTIVE: Identification and characterization of hematopoietic stem cells in peripheral blood (PB) and cord blood (CB) have suggested feasible alternatives to conventional allogeneic bone marrow (BM) transplantation. The growing interest in this use of allogeneic stem cells has prompted the Working Group on CD34-positive Hematopoietic Cells to review this subject by analyzing its biological and technical aspects. EVIDENCE AND INFORMATION SOURCES: The method used for preparing this review was informal consensus development. Members of the Working Group met three times, and the participants at these meetings examined a list of problems previously prepared by the chairman. They discussed the individual points in order to reach an agreement on the various concepts, and eventually approved the final manuscript. Some of the authors of the present review have been working in the field of hematopoietic stem cell biology and processing, and have contributed original papers published in peer-reviewed journals. In addition, the material examined in the present review includes articles and abstracts published in journals covered by the Science Citation Index and Medline. STATE OF ART: Several studies have now shown that hematopoietic stem cells collected from peripheral blood after the administration of G-CSF, or from cord blood upon delivery, are capable of supporting rapid and complete reconstitution of BM function in allogeneic recipients. Perhaps more importantly, reinfusion of large numbers of HLA-matched T-cells from PB collections or T-cells with various degrees of HLA disparity from CB did not result in a higher incidence or greater severity of acute graft-versus-host disease than expected with BM. Based on the data reviewed, operative guidelines for mobilization, collection and graft processing are provided. PERSPECTIVES: It should be remembered that despite the growing interest, these procedures must be still considered as advanced clinical research and should be included in formal clinical trials aimed at demonstrating their definitive role in stem cell transplantation. In this regard, a large European randomized study is currently comparing PB and BM allografts. However, the possibility of collecting large quantities of hematopoietic progenitor-stem cells, perhaps with reduced allo-reactivity, offers an exciting perspective for widening the number of potential stem cell donors and greater leeway for graft manipulation than is possible with BM.

A moderate transfusion regimen may reduce iron loading in beta-thalassemia major without producing excessive expansion of erythropoiesis.

BACKGROUND: Hypertransfusion with a baseline hemoglobin of 10 to 12 g per dL is still considered by many to be the mainstay of conservative therapy for beta-thalassemia major. However, this regimen is frequently associated with manifestations of transfusion iron overload, despite regular chelation therapy with subcutaneous desferoxamine. STUDY DESIGN AND METHODS: To verify whether a transfusion regimen with a target pretransfusion hemoglobin level between 9 and 10 g per dL can allow a significant reduction in blood consumption, while still effectively suppressing erythropoiesis, the records were reviewed of 32 beta-thalassemia major patients, who were maintained at a pretransfusion hemoglobin of 11.3 +/- 0.5 g per dL between 1981 and 1986. These patients were switched at the beginning of 1987 to a transfusion regimen with pretransfusion hemoglobin of 9.4 +/- 0.4 g per dL. The degree of erythroid marrow activity was evaluated in these patients and in 32 subjects with beta-thalassemia intermedia through the simple measurement of serum transferrin receptor. RESULTS: After the adoption of the moderate transfusion regimen, transfusion requirements decreased from 137 +/- 26 to 104 +/- 23 mL per kg per year of red cells (p < 0.0001), and mean serum ferritin decreased from 2448 +/- 1515 to 1187 +/- 816 micrograms per L (p < 0.0001), with one-half of patients achieving serum ferritin levels lower than 1000 micrograms per L. The proportion of patients having spontaneous pubertal development increased significantly (p < 0.01), as a result of less iron-related gonadotropin insufficiency. At the lower pretransfusion hemoglobin, erythroid marrow activity did not exceed two to three times normal levels in most subjects. CONCLUSION: As compared with hypertransfusion, moderate transfusion may allow more effective prevention of iron loading, with higher likelihood of spontaneous pubertal development and without producing excessive expansion of erythropoiesis.

Prediction of response to recombinant human erythropoietin (rHuEpo) in anemia of malignancy.

BACKGROUND: Since only a portion of anemic patients outside the uremia setting benefit from erythropoietin treatment, a reliable means of predicting potential responders and nonresponders would be very useful. MATERIALS AND METHODS: We retrospectively reviewed the clinical records of 58 patients with refractory anemia associated with various malignant disorders who had been treated with subcutaneous rHuEpo. The starting rHuEpo dose was 375 U/kg/week for 4 weeks, and was increased to 750 U/kg/week for another 4 weeks if no response was observed. Response was defined as a Hb increase > or = 2 g/dL with no need for blood transfusion. We examined the value of various laboratory parameters (baseline levels, 2-week and 4-week changes) as predictors of response. Endogenous erythropoietin production was evaluated by its serum level and erythroid activity was assessed through reticulocyte count and circulating transferrin receptor. RESULTS: Forty-eight individuals were evaluable, 58% of whom responded to rHuEpo within 8 weeks. Multiple regression analysis showed that 53% of the variation in the 8-week Hb concentration was explained by variations in baseline serum erythropoietin and the 2-week change in serum transferrin receptor (p < 0.001). Based on these two parameters, response prediction in individual patients would have resulted in a sensitivity of 96%, a specificity of 79% and an overall accuracy of 88%. In addition, 58% of the variation in the 8-week Hb was explained by variations in the 4-week changes in Hb and reticulocyte count (p < 0.001). Utilizing these latter parameters and baseline serum erythropoietin, response prediction in individual patients would have resulted in a sensitivity of 92%, a specificity of 82% and an overall accuracy of 88%. CONCLUSIONS: This retrospective analysis suggests that response to rHuEpo can be reasonably predicted by pretreatment serum erythropoietin together with early changes in simple laboratory parameters.

Characterization of primitive subpopulations of normal and leukemic cells present in the blood of patients with newly diagnosed as well as established chronic myeloid leukemia.

Elevated numbers of primitive Philadelphia chromosome-positive (Ph+) progenitors, including long-term culture-initiating cells (LTC-IC) as well as colony-forming cells (CFC), have been previously described in the blood of patients with chronic myeloid leukemia (CML) in chronic phase with high white blood cell counts. In the present study, which focused primarily on an analysis of circulating progenitors present in such patients at diagnosis, we discovered the frequent and occasionally exclusive presence of circulating normal (Ph-) LTC-IC, often at levels above those seen for LTC-IC in the blood of normal individuals. The presence of detectable numbers of circulating Ph- LTC-IC was independent of the fact that the same peripheral blood samples also contained elevated numbers of predominantly or exclusively Ph+ CFC. Interestingly, both the Ph+ and Ph- LTC-IC in these samples were CD34+CD71- and variably CD38- and Thy-1+, as previously documented for LTC-IC in normal marrow. Thus, neither CD38 nor Thy-1 expression was useful for discriminating between Ph+ and Ph- LTC-IC in mixed populations. Nevertheless, an association of these phenotypes with LTC-IC function did allow highly enriched (> 5% pure) suspensions of either Ph+ or Ph- LTC-IC to be obtained from selected samples of CML blood in which the initial LTC-IC population was either predominantly Ph+ or Ph-, respectively. These findings suggest that the mechanisms causing mobilization of leukemic stem cells in untreated CML patients may affect their normal counterparts. They also indicate a possible new source of autologous cells for the support of intensive therapy of CML patients. Finally, they provide a method for obtaining the most highly purified populations of Ph+ LTC-IC described to date. This method should be useful for further analyses of the molecular activities of these very primitive neoplastic cells.

Defective iron supply for erythropoiesis and adequate endogenous erythropoietin production in the anemia associated with systemic-onset juvenile chronic arthritis.

Systemic-onset juvenile chronic arthritis (SoJCA) is associated with high levels of circulating interleukin-6 (IL-6) and is frequently complicated by severe microcytic anemia whose pathogenesis is unclear. Therefore, we studied 20 consecutive SoJCA patients with hemoglobin (Hb) levels <12 g/dL, evaluating erythroid progenitor proliferation, endogenous erythropoietin production, body iron status, and iron supply for erythropoiesis. Hb concentrations ranged from 6.5 to 11.9 g/dL. Hb level was directly related to mean corpuscular volume (r = .82, P < .001) and inversely related to circulating transferrin receptor (r = -.81, P < .001) suggesting that the severity of anemia was directly proportional to the degree of iron-deficient erythropoiesis. Serum ferritin ranged from 18 to 1,660 microgram/L and was unrelated to Hb level. Bone marrow iron stores wore markedly reduced in the three children investigated, and they also showed increased serum transferrin receptor and normal-to-high serum ferritin. All 20 patients had elevated IL-6 levels and normal in vitro growth of erythroid progenitors. Endogenous erythropoietin (epo) production was appropriate for the degree of anemia as judged by both the observed to predicted log (serum epo) ratio 10.95 +/- 0.12) and a comparison of the serum epo-Hb regression found in these subjects with that of thalassemia patients. Multiple regression analysis showed that serum transferrin receptor was the parameter most closely related to hemoglobin concentration: variation in circulating transferrin receptor explained 61% of the variation in Hb level (P < .001). In 10 severely anemic patients, amelioration of anemia following intravenous iron administration resulted in normalization of serum transferrin receptor. Defective iron supply to the erythron rather than blunted epo production is the major cause of the microcytic anemia associated with SoJCA. A true body-iron deficiency caused by decreased iron absorption likely complicates long-lasting inflammation in the most anemic children, and this can be recognized by high serum transferrin receptor levels. Although oral iron is of no benefit, intravenous iron saccharate is a safe and effective means for improving iron availability for erythropoiesis and correcting this anemia. Thus, while chronically high endogenous IL-6 levels do not appear to blunt epo production, they are probably responsible for the observed abnormalities in iron metabolism. Anemia of chronic disease encompasses a variety of anemic conditions whose peculiar features may specifically correlate with the type of cytokine(s) predominantly released.