Flow cytometric reticulocyte quantification in the evaluation of hematologic recover

Abstract: The role of flow cytometric reticulocyte (RET) counting and the immature RET fractions (IRF) in the evaluation of hematopoietic recovery following chemoradiotherapy-induced aplasia was studied. RET counts and IRF were studied using an automated flow cytometric reticulocyte counter (Sysmex R-2000) in three groups of patients: 58 patients undergoing an autologous bone marrow transplantation (ABMT group), 28 of whom received granulocyte colony-stimulating factor (G-CSF); 28 patients undergoing an allogeneic bone marrow transplantation (BMT group); and 28 patients receiving remission-induction chemotherapy for acute leukemia (CHEMO group). To evaluate the IRF the percentages of RET fractions with middle and high fluorescence reticulocyte (MFR and HFR, respectively) were used. A rising IRF (expressed as the percentage of MFR ± HFR) was the first sign of hematopoietic recovery (ABMT group, IRF 9 days versus 18 days for the absolute neutrophil count (ANC); BMT group, 15 versus 18 days; CHEMO group, 9 versus 11 days). When recovery of the ANC (>0.5 times 109/1) was compared with that of the IRF (MFR ± HFR > 5%), statistically significant differences were found in all three groups. Additionally, 93.1% of the ABMT, 92% of the BMT and 91.2% of the CHEMO recovered the IRF before the ANC. In conclusion, an elevation in the percentage of IRF is the first sign of hematologic recovery in the majority of patients receiving remission-induction chemotherapy and the first sign of engraftment in those submitted to ABMT or BMT. Serial automated flow cytometric quantitative reticulocyte counting provides a useful and early measure of erythropoiesis indicative of hematopoietic reconstitution or successful bone marrow engraftment following marrow transplantation.     

Clinical course of thrombocytopenia in patients treated with imatinib mesylate for accelerated phase chronic myelogenous leukemia

We studied 28 patients with accelerated phase chronic myelogenous leukemia (CML) who were enrolled on the Novartis expanded access study 114. Diagnosis of accelerated phase CML was based on karyotypic evolution (n = 9) and hematologic criteria (n = 18). All patients were begun on 600 mg/day of imatinib mesylate. Dose reductions to 400 mg/day and then 300 mg/day were prescribed for an absolute neutrophil count (ANC) of <0.5/microl or a platelet count of <20,000/microl. Twenty-seven of the 28 patients continued treatment for a median of 34 weeks. Eleven patients developed thrombocytopenia following an average of 8.4 +/- 1.4 weeks of therapy. The onset of thrombocytopenia was associated with disease progression in one patient and a decline in bone marrow megakaryocytes in the other 10. Nine patients recovered to a platelet count of >20,000/microl after an average of 19.7 +/- 1.8 weeks. Patients who developed thrombocytopenia had a longer duration of disease (9.39 vs. 4.35 years; P < 0.01) and were more likely to be diagnosed with accelerated phase CML by hematologic criteria. Hematologic responses in patients with and without thrombocytopenia were comparable; however, 31.3% of patients without thrombocytopenia had a complete cytogenetic response compared to none of those with thrombocytopenia. Grade III-IV thrombocytopenia is common in accelerated phase CML and may be a marker for the inability to achieve cytogenetic response using single agent imatinib mesylate.     

Economic analysis of a phase III study of G-CSF vs placebo following allogeneic blood stem cell transplantation

Hematopoietic colony-stimulating factors (CSF) decrease the duration of neutropenia following stem cell transplantation (SCT). With CSF-mobilized allogeneic blood SCT (alloBSCT), the yields of CD34+ cells are several-fold higher than in other SCT settings, raising concern that post-transplant CSF use may be unnecessary. In this study, we estimate the resource and cost implications associated with CSF use following alloBSCT. A cost identification analysis was conducted for 44 patients on a randomized, double-blind placebo-controlled trial of G-CSF following alloBSCT. Study drug was given daily until an absolute neutrophil count (ANC) > or = 1000 cells/microl. Billing information from the time of transplant to day +100 was analyzed. The median number of days to an ANC > or = 500 cells/microl was shorter in the G-CSF arm, 10.5 days vs 15 days (P < 0.001), while platelet recovery and rates of acute graft-versus-host disease (GVHD) and survival were similar. Resource use was similar, including days hospitalized, days on antibiotics, blood products transfused and outpatient visits. Total median post-transplant costs were $76577 for G-CSF patients and $78799 for placebo patients (P = 0.93). G-CSF following allogeneic blood SCT decreased the median duration of absolute neutropenia and did not incur additional costs, but did not result in shorter hospitalizations, or less frequent antibiotic use.     

Use of recombinant human granulocyte-macrophage colony-stimulating factor in patients with lymphoid malignancies transplanted with unpurged or adjusted-dose mafosfamide-purged autologous marrow.

The neutropenia-related morbidity and mortality occurring after autologous bone marrow transplantation (ABMT) is increased by marrow purging procedures. While phase I through III clinical trials showed the enhancing activity of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) on neutrophil recovery after ABMT with unpurged marrow, controversial results have been reported when purged marrow was used. Therefore, it was the aim of the present study to evaluate the efficacy of rhGM-CSF administration in a group of patients (n = 15) with lymphoid malignancies transplanted in complete remission with mafosfamide-purged (n = 10) or unpurged (n = 5) marrow. Mafosfamide concentrations used for marrow purging were evaluated on an individual basis by means of a recently described technique that destroys the granulocyte-macrophage (granulocyte-macrophage colony-forming units [CFU-GM]) compartment, but spares 50% of the more primitive stroma adherent colony-forming cells (CFU-Blast). rhGM-CSF (10 micrograms/kg/d) was started within 24 hours of ABMT and administered in a 4-hour infusion daily until the absolute neutrophil count (ANC) reached 500 x 10(6)/L and then for 7 more days. Patients receiving mafosfamide-purged or unpurged marrow failed to show any difference in terms of median number of days required to achieve an ANC > or = 500 x 10(6) (13 v 14.0, P > .4) cells/L. As compared with retrospective controls, granulocytic recovery was reduced by a median time of 11 (P < or = .0005) and 5 (P < or = .0005) days for patients grafted with purged and unpurged marrow, respectively. The number of CFU-GM (mean +/- SD) infused per kilogram of body weight was significantly lower in patients who received purged autografts as compared with those receiving unpurged autografts (0.85 +/- 0.79 x 10(4) v 15.7 +/- 9.2 x 10(4), P < or = .0005). The dose of CFU-GM progenitors infused per kilogram of body weight did not correlate (r = .031, P > .05) with the time required to reach an ANC > or = 500 x 10(6) cells/L. The number of CFU-Blast (mean +/- SD) infused per kilogram of body weight was not significantly different between patients who received purged or unpurged autografts (5.05 +/- 2.51 x 10(3)/kg v 6.18 +/- 2.66 x 10(3)/kg, P < or = .375). A statistically significant correlation (r = -.658, P < or = .05) was observed between the number of CFU-Blast infused and the number of days required to reach an ANC > or = 500 x 10(6) cells/L.(ABSTRACT TRUNCATED AT 400 WORDS)     

Randomized comparison of two different schedules of granulocyte colony-stimulating factor administration after allogeneic bone marrow transplantation.

We performed a randomized trial to determine whether there are differential effects of G-CSF when it is either started on the day (day 0 group) or on the 6th day of marrow infusion (day 5 group) in the allogeneic BMT setting. G-CSF 450 microg was given intravenously daily until the peripheral blood ANC was over 3000/microl. Between May 1995 and April 1998, 60 patients were enrolled (30 in each group). Median number of days of G-CSF administration was significantly longer for the day 0 group (18.5 vs 14.0 days, P < 0. 001). Median days to an ANC over 500/microl were the same in both groups (16 days). Median days to an unsupported platelet count of 20 000/microl did not show significant differences (29.5 vs 28 days, P = 0.202). The frequency of hepatic VOD was higher for the day 0 group (66.7 vs 40.0%, P = 0.038). Mean plasma antithrombin III level was significantly lower in the day 0 group on post-transplant day 7 (83.6 vs 93.9%, P = 0.009). Patients in the day 0 group showed significantly worse 100-day survival (25/30 vs 30/30 surviving respectively, P = 0.019). In conclusion, early initiation of G-CSF after allogeneic BMT did not facilitate marrow engraftment. In addition, early administration of G-CSF was associated with a higher frequency of VOD and a significant fall in plasma antithrombin III level.     

Mortality hazard functions as related to neutropenia at different times after marrow transplantation

We characterized the relationship between severe neutropenia and risk of death in 2,276 patients after marrow transplantation to define objective and clinically relevant criteria that could be used to judge the timing and potential value of interventions designed to improve survival in patients with delayed initial engraftment. Proportional hazard models were used to estimate the relative risk of death before day 100 among patients alive on any given day with an absolute neutrophil count (ANC) less than 100/microL compared with those alive on the same day with an ANC > or = 100/microL. Between day 10 and 14, the risk ratio remained close to 1.0, indicating that the risk of death before day 100 for patients with an ANC less than 100/microL was similar to that for patients with an ANC > or = 100/microL. Between day 15, when 38% of patients had an ANC less than 100/microL, and day 26, when 3.8% of patients had an ANC less than 100/microL, the risk ratio showed an overall upward trend, indicating that patients with an ANC less than 100/microL had a higher risk of death before day 100 than those with an ANC > or = 100/microL. Thereafter, the risk ratio fluctuated between 2.01 and 5.78, indicating consistently higher risks of mortality in patients with severe neutropenia. However, allogeneic and autologous transplant recipients each had distinctive risk ratio patterns. These results could be helpful in deciding the appropriate timing for treatment given to improve graft function after marrow transplantation.     

Influence of recombinant human granulocyte colony-stimulating factor (filgrastim) on hematopoietic recovery and outcome following allogeneic bone marrow transplantation (BMT) from volunteer unrelated donors.

Effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF, filgrastim) on hematopoietic recovery and clinical outcome in patients undergoing allogeneic bone marrow transplantation (BMT) from volunteer unrelated donors (VUD) were analyzed retrospectively. Additionally, the influence of baseline patient and transplant characteristics on hematopoietic recovery was evaluated. From January 1994 to March 1996, 47 consecutive adult patients received VUD-BMT. GVHD prophylaxis was cyclosporin A/short course methotrexate/prednisolone, and in four patients additional ATG. Post-transplantation, cohorts of patients received rhG-CSF (5 microg/kg/day) (n = 22) or no rhG-CSF (n = 25) in a non-randomized manner. The patient groups with and without rhG-CSF were rather comparable with respect to baseline patient and transplant characteristics. Median time to neutrophil counts (ANC) >500/microl was 14 days with rhG-CSF vs 16 days without rhG-CSF (P = 0.048), to ANC >1000/microl was 15 vs 18 days (P = 0.084). Neutrophil recovery was accelerated in patients receiving more than the median MNC dose of 2.54 x 10(8)/kg with a median time to ANC >1000/microl of 13 days vs 19 days (P = 0.017). RhG-CSF did not influence platelet recovery and incidence of infectious complications. Incidence of acute GVHD II-IV was 50% with rhG-CSF and 28% without rhG-CSF (P = 0.144), but death before acute GVHD II-IV occurred in 9% of patients with and 20% of patients without rhG-CSF. The median follow-up time was 38 and 36 months in patients with and without rhG-CSF, respectively. Survival at 2 years post-transplant was 39% (95% confidence interval (18%, 60%)) in patients with rhG-CSF and 24% (95% confidence interval (7%, 41%)) in patients without rhG-CSF. Administration of rhG-CSF after VUD-BMT may lead to more rapid neutrophil recovery, but did not influence the incidence of infectious complications. Patients receiving rhG-CSF showed a slightly higher incidence of acute GVHD II-IV. Higher numbers of MNC in the marrow graft accelerated hematopoietic engraftment.     

Recombinant human granulocyte-macrophage colony-stimulating factor accelerates engraftment kinetics after allogeneic bone marrow transplantation for childhood acute lymphoblastic leukemia

BACKGROUND AND OBJECTIVE: The use of recombinant human granulocyte-macrophage stimulating factor (rhGM-CSF) has been shown to be well-tolerated and to reduce post-transplantation morbidity in adults undergoing HLA-identical allogeneic bone marrow transplantation (BMT). There is however, limited experience in children. DESIGN AND METHODS: We performed a prospective, comparative multicenter trial using rhGM-CSF after allogeneic BMT in children with acute lymphoblastic leukemia (ALL). The study comprised 24 patients with ALL who received rhGM-CSF and 22 patients with ALL who did not receive rhGM-CSF. There were no statistically significant differences in the demographic characteristics between the rhGM-CSF-treated and untreated groups. rhGM-CSF was given at a dose of 10 micrograms/kg/day infusion over 4 hours from day +1 until +28 or until the absolute neutrophil count (ANC) was > or = 1 x 10(9)/L. All patients received HLA-identical sibling marrow and cyclosporine alone for graft-versus-host disease (GvHD) prophylaxis. The number of cells infused was similar in both groups. A software program (Statview 4.0, Abacus Concept, Inc., Berkeley, CA, USA) was used for statistical analysis. RESULTS: The median of days to achieve ANC > or = 0.5 x 10(9)/L was shorter in the rhGM-CSF-treated patients (14 days vs 18.5 days; p < 0.0001). Patients who received rhGM-CSF had a lower incidence of grade III-IV mucositis. The duration of hospital stay was significantly shorter in patients who received rhGM-CSF (31 days vs 45 days; p < 0.005). No differences in GvHD severity, relapse or survival were observed. At the dose and schedule used in the present study, rhGM-CSF was well-tolerated and no side effects were observed. INTERPRETATIONS AND CONCLUSIONS: rhGM-CSF at a dose of 10 micrograms/kg/day in children with ALL undergoing allogeneic BMT is well tolerated, accelerates neutrophil and platelet engraftment, reduces the intensity and severity of mucositis and permits a more rapid discharge from hospital.     

Autologous SCT with a dose-reduced BU and CY regimen in older patients with non-Hodgkin's lymphoma

Autologous SCT is a potentially curative procedure for patients with relapsed lymphoma (NHL). We analyzed the outcomes of 34 patients > or =60 years old, including eight patients > or =70 years old, who received BU and CY and SCT for NHL. Patients received BU 0.8 mg/kg i.v. (n=25) or 1 mg/kg p.o. (n=9) q 6 h x 14 doses and CY 60 mg/kg i.v. q day x 2 days. The median age was 66 (range, 60-78) years. Twenty-two patients had large cell, 10 follicular and two-mantle cell lymphoma. Fifteen patients were in a second or greater CR and 19 patients were in a PR. The median days to ANC >500/microl and platelet count >50,000/microl were 10 and 13 days respectively. The 100-day transplant-related mortality was 0%. Toxicities included interstitial lung disease (n=2), seizures in a patient with CNS lymphoma (n=1), mild veno-occlusive disease (n=2), and transient atrial fibrillation (n=4). With a median follow-up of 40 months, the 2-year overall survival and PFS were 67 and 54% respectively. BU/CY is a well-tolerated conditioning regimen for older patients with NHL. Age alone should not be used as an exclusion criterion for autologous SCT.     

Iron overload is a major risk factor for severe infection after autologous stem cell transplantation: a study of 367 myeloma patients

We evaluated the risk factors for infection of 367 consecutive myeloma patients who underwent high-dose melphalan and autologous stem cell transplantation (ASCT). Examination of bone marrow iron stores (BMIS) prior to ASCT was used to evaluate body iron stores. Other variables included age, sex, active smoking, myeloma remission status, severity of mucositis and duration of severe neutropenia post-ASCT (<100 absolute neutrophils counts (ANC)/microl). Median age was 56 years; 61% of patients were males. 140 episodes of severe infections occurred in 116 patients, including bacteremia (73), pneumonia (40), severe colitis (25) and bacteremia with septic shock (two). The infection incidence per 1,000 days at risk was 45.2. Pre-ASCT risk factors for severe infection by univariate analysis were increased BMIS (OR=2.686; 95% CI 1.707-4.226; P<0.0001), smoking (OR=1.565; 95% CI 1.005-2.437; P=0.0474) and male gender (OR=1.624; 95% CI 1.019-2.589; P=0.0414). Increased BMIS (OR=2.716; 95% CI 1.720-4.287; P<0.0001) and smoking (OR=1.714; 95% CI 1.081-2.718; P=0.022) remained significant by multivariate analysis. Duration of ANC <100 micro/l (OR=1.129; 95% CI 1.039-1.226; P=0.0069 and OR=1.127; 95% CI 1.038-1.224; P=0.0045 by both univariate and multivariate analysis, respectively) was the only post-ASCT risk factor for infection. Increased pre-transplant BMIS and smoking are significant predictors of severe infection after myeloablative chemotherapy followed by ASCT in myeloma patients.     

Impact of baseline viral load and adherence on survival of HIV-infected adults with baseline CD4 cell counts > or = 200 cells/microl

BACKGROUND: Baseline plasma HIV RNA levels > 100 000 copies/ml have been associated with elevated mortality rates after the initiation of HAART. There is uncertainty regarding the optimal strategy for patients with high plasma HIV RNA but CD4 cell count > or = 200 cells/microl. OBJECTIVE: To evaluate the impact of baseline plasma HIV RNA on survival among patients with CD4 cell counts > or = 200 cells/microl. METHODS: Patients were stratified by plasma HIV RNA, CD4 cell count and adherence level. Mortality rates were evaluated using Kaplan-Meier methods and Cox regression. RESULTS: Among 1166 patients initiating HAART with a CD4 cell count > or = 200 cells/microl, a baseline HIV RNA > or = 100 000 copies/ml was statistically associated with elevated mortality among non-adherent patients (log-rank P = 0.032), but not for adherent patients (log-rank P = 0.690). In a multivariate Cox model comparing patients with a baseline CD4 cell count > or = 200 cells/microl and a baseline plasma HIV RNA < 100 000 copies/ml, the mortality rate was statistically similar among patients with a baseline CD4 cell count > or = 200 cells/microl and a baseline plasma HIV RNA > or = 100 000 copies/ml (relative hazard, 1.21; 95% confidence interval, 0.89-1.65; P = 0.232). CONCLUSION: HIV RNA > or = 100 000 copies/ml was only associated with mortality among HIV-infected patients initiating HAART with CD4 cell counts > or= 200 cells/microl if the patients were non-adherent.     

Reduced-intensity allogeneic stem cell transplantation in relapsed and refractory Hodgkin's disease: low transplant-related mortality and impact of intensity of conditioning regimen

A total of 40 patients with relapsed/refractory Hodgkin's disease (HD) underwent reduced-intensity conditioning (RIC) allogeneic stem cell transplantation (allo-SCT) from an HLA-identical sibling (n=20) or a matched unrelated donor (n=20). The median age was 31 years (range 18-58). Disease status at allo-SCT was refractory relapse (n=14) or sensitive relapse (n=26). The conditioning regimens were fludarabine-cyclophosphamide+/-antithymocyte globulin (n=14), a less intensive regimen, and fludarabine-melphalan (FM) (n=26), a more intensive one. The two groups had similar prognostic factors. The median time to neutrophil recovery (ie absolute neutrophil count >/=500/microl) was 12 days (range 10-24). The median time to platelet recovery (ie platelet count >/=20 000/microl) was 17 days (range 7-132). Day 100 and cumulative (18-month) transplant-related mortalities (TRMs) were 5 and 22%. Twenty-four patients (60%) are alive (14 in complete remission or complete remission, unconfirmed/uncertain) with a median follow-up of 13 months (4-78). In all, 16 patients expired (TRM n=8, disease progression n=8). FM patients had better overall survival (73 vs 39% at 18 months; P=0.03), and a trend towards better progression-free survival (37 vs 21% at 18 months; P=0.2). RIC allo-SCT is feasible in relapsed/refractory HD patients with a low TRM. The intensity of the preparative regimen affects survival.     

Rate of AIDS diseases or death in HIV-infected antiretroviral therapy-naive individuals with high CD4 cell count

OBJECTIVE: To assess the absolute rate of AIDS and death in antiretroviral therapy (ART)-naive patients with a high CD4 cell count. Such information would be helpful in the design of a trial investigating early initiation of ART. DESIGN: Analysis of data from an ongoing HIV cohort study. METHODS: The rate of (severe) AIDS or death and death alone was evaluated in ART-naive patients according to the current CD4 cell count, focusing on CD4 cell counts > or = 350 cells/microl among patients in the UK CHIC Study. RESULTS: In a total of 30 313 person-years of follow-up, there were 1557 AIDS or death events. The rate of AIDS or death in persons with most recent CD4 cell count 350-499, 500-649 and > 650 cells/microl was 2.49, 1.54 and 0.96 per 100 person-years, respectively. The rate ratio for those with CD4 cell count 500-649 cells/microl compared with those with CD4 cell count > or = 650 cells/microl was 1.55 [95% confidence interval (CI), 1.11-2.17; P = 0.01]. In a Poisson regression model based on person years with CD4 cell count > or = 350 cells/microl , there was a strong effect of CD4 cell count on rate of AIDS or death (rate ratio, 0.84; 95% CI, 0.76-0.93; P = 0.001), independent of viral load and age. CONCLUSIONS: The trend of decreasing rate of AIDS and death with higher CD4 cell count is present throughout the CD4 cell count > or = 350 cells/microl range in ART-naive people.     

Combined administration of alpha-erythropoietin and filgrastim can improve the outcome and cost balance of autologous stem cell transplantation in patients with lymphoproliferative disorders

We compared the use of G-CSF plus EPO in a group of 32 multiple myeloma and lymphoma patients with historical controls receiving G-CSF alone. Haemopoietic reconstitution was significantly faster in patients receiving G-CSF+EPO (group B), with a median time of 10 days to achieve an ANC count >0.5 x 10(9)/l, compared to 11 days in the historical group (A). The median duration of severe neutropenia (ANC count <100/ml) was significantly shorter in group B compared to group A; platelet counts >20 x 10(9) and >50 x 10(9)/l were achieved at days + 13 and + 17, respectively in group B, compared to days + 14 and + 24, respectively, in group A (P = 0.015, 0.002) patients. The transfusion requirement was reduced in group B, with 0 (0-6) RBC units and 1 (0-5) platelet unit transfused in group B vs 2 RBC (0-9) and 2 platelet units (0-8) in group A. Median days of fever, antibiotic therapy and hospital stay were reduced in group B (9.5 days vs 22). The mean cost of autotransplantation per group A patient was 23,988 Euro, compared with 18,394 Euro for a group B patient. Our study suggests that the EPO + G-CSF combination not only accelerates engraftment kinetics, but can also improve the clinical course of ASCT.     

Effect of stem cell factor with and without granulocyte colony-stimulating factor on neonatal hematopoiesis: in vivo induction of newborn myelopoiesis and reduction of mortality during experimental group B streptococcal sepsis.

Neonatal hematopoiesis and host defense are developmentally immature and under states of increased demand predispose the newborn to peripheral cytopenias and depletion of bone marrow storage pool reserves. We have previously demonstrated that recombinant human granulocyte colony-stimulating factor (rhG-CSF) can significantly modulate neonatal rat granulopoiesis and act synergistically with antibiotic therapy to reduce the mortality rate during experimental group B streptococcal sepsis. Stem cell factor (SCF) has been shown to stimulate early hematopoietic progenitor cells and, in the presence of lineage-specific CSFs, enhance committed progenitor cell proliferation. In the present study we examined the in vivo neonatal hematologic effects of recombinant rat (rr) SCF (14 days), simultaneous rrSCF + rhG-CSF (14 days), and sequential combination of rrSCF (7 days) + rhG-CSF (7 days). Sprague-Dawley newborn rats (less than or equal to 24 hours) were injected intraperitoneal (IP) x 14 days with the above combinations. rrSCF (0 to 200 micrograms/kg/d) had a negligible effect on the peripheral platelet count and absolute neutrophil count (ANC) but the diminution in the hematocrit during the first 10 days of treatment was less pronounced (P = .0001). However, the simultaneous use of rrSCF + rhG-CSF synergistically increased the circulating day 6 to 13 ANC (P = .001). Similarly, sequential rrSCF + rhG-SCF also had a synergistic significant effect during the second week of therapy on the circulating ANC (P = .01). The bone marrow neutrophil storage and proliferative pools were also significantly increased in newborn rats treated with rrSCF + rhG-CSF versus rhG-CSF (P = .02). The bone marrow and liver/spleen CFU-GM pool was unchanged; however, the CFU-GM proliferative rates were significantly increased in the rrSCF + rhG-CSF group (P = .04). rrSCF also induced a significant increase in the bone marrow and liver/spleen mast cell pool (P = .002). Lastly, rrSCF x 14 days +/- rhG-CSF significantly reduced the mortality rate at 48 and 120 hours after experimental group B streptococcus sepsis (P = .03 and .05, respectively). These data suggest that combination SCF + G-CSF therapy compared with G-CSF alone significantly increases the neonatal rat peripheral neutrophil count, bone marrow myeloid pools and proliferative rates, and induces a reduction in the mortality rate during experimental bacterial sepsis. SCF therapy may have future potential applications in the modulation of human neonatal hematopoiesis and host defense.     

The ligand for c-kit, stem cell factor, stimulates the circulation of cells that engraft lethally irradiated baboons.

Recombinant human stem cell factor (SCF), the ligand for c-kit, has been shown to stimulate increased numbers of hematopoietic progenitor cells of multiple types to circulate in the blood of baboons, but it was not known if the cells stimulated to circulate by SCF contained cells capable of engrafting and rescuing lethally irradiated baboons. Peripheral blood mononuclear cells (PBMNC) were collected by leukapheresis from four untreated control baboons and from three baboons on the 10th or 11th day of treatment with SCF (200 micrograms/kg/d). All animals were transplanted with 1.00 to 1.04 x 10(8)/kg of cryopreserved autologous PBMNC after treatment with a single dose of 1,020 cGy total body irradiation (TBI). Three animals were transplanted with PBMNC that had been collected during SCF treatment, 24 to 38 days after the last dose of SCF. Rapid trilineage engraftment was documented by bone marrow biopsy in all three. The mean time to a total white blood cell count (WBC) > or = 500/microL, WBC > or = 1,000/microL, and an absolute neutrophil count (ANC) > or = 500/microL was 15 +/- 3 (mean +/- SD), 19 +/- 1, and 19 +/- 2 days, respectively. Two animals remain alive with stable engraftment more than 180 and 245 days posttransplant. The third died of sepsis 32 days posttransplant with a hypercellular marrow showing trilineage engraftment. The surviving animals were transfusion independent by 10 and 59 days posttransplant. Four control animals were transplanted with PBMNC collected in the absence of SCF stimulation. One was treated for 11 days with SCF (200 micrograms/kg/d) after PBMNC were collected. This animal was transplanted 25 days after the last dose of SCF. None of the four control animals engrafted and they died 13, 16, 28, and 38 days posttransplant with marrow aplasia. Treatment with SCF stimulates the circulation of cells that engraft and rescue lethally irradiated baboons. The characteristics of the transplantable cells present in the circulation are now amenable to direct study.     

Prolonged survival associated with early lymphocyte recovery after autologous hematopoietic stem cell transplantation for patients with metastatic breast cancer.

Early absolute lymphocyte count (ALC) recovery at day 15 post-autologous stem cell transplantation (ASCT) is a powerful prognostic indicator for survival in multiple myeloma and non-Hodgkin's lymphoma. The relationship of ALC with clinical outcomes in metastatic breast cancer is unknown. We evaluated all 29 patients with metastatic breast cancer who underwent ASCT at the Mayo Clinic, Rochester, Minnesota, from 1994 to 1999. The ALC threshold was set at 500 cells/microl on day 15 post-ASCT based on previous experience with hematologic malignancies. All patients were followed for a minimum of 2 years or until death, with a median follow-up for living patients of 2.25 years. Of the 29 patients, 17 have died with disease progression, two are alive and have progressed, and 10 are alive without progression. The median overall and progression-free survival times were significantly better for the 20 patients with ALC > or = 500 cells/microl compared with the nine patients with ALC <500 cells/microl (not reached vs 14 months, P < 0.0001; 24 vs 7 months, P < 0.0015, respectively). In conclusion, ALC > or = 500 cells/microl on day 15 post-ASCT was associated with significantly better survival in patients with metastatic breast cancer, suggesting the importance of early immune recovery post-ASCT in these patients.     

Results of a phase I/II trial of recombinant human granulocyte- macrophage colony-stimulating factor in very low birthweight neonates: significant induction of circulatory neutrophils, monocytes, platelets, and bone marrow neutrophils

Neonates, especially those of very low birthweight (VLBW), have an increased risk of nosocomial infections secondary to deficiencies in development. We previously demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) production and mRNA expression from stimulated neonatal mononuclear cells are significantly less than that from adult cells. Recombinant murine GM-CSF administration to neonatal rats has resulted in neutrophilia, increased neutrophil production, and increased survival of pups during experimental Staphylococcus aureus sepsis. In the present study, we sought to determine the safety and biologic response of recombinant human (rhu) GM-CSF in VLBW neonates. Twenty VLBW neonates (500 to 1,500 g), aged < 72 hours, were randomized to receive either placebo (n = 5) or rhuGM-CSF at 5.0 micrograms/kg once per day (n = 5), 5.0 micrograms/kg twice per day (n = 5), or 10 micrograms/kg once per day (n = 5) given via 2-hour intravenous infusion for 7 days. Complete blood counts, differential, and platelet counts were obtained, and tibial bone marrow aspirate was performed on day 8. Neutrophil C3bi receptor expression was measured at 0 and 24 hours. GM-CSF levels were measured by a sandwich enzyme-linked immunosorbent assay at 2, 4, 6, 12, and 24 hours after the first dose of rhuGM-CSF. At all doses, rhuGM-CSF was well tolerated, and there was no evidence of grade III or IV toxicity. Within 48 hours of administration, there was a significant increase in the circulating absolute neutrophil count (ANC) at 5.0 micrograms/kg twice per day and 10.0 micrograms/kg once per day, which continued for at least 24 hours after discontinuation of rhuGM-CSF. When the ANC was normalized for each patient's first ANC, there was a significant increase in the ANC on days 6 and 7 at each dose level. By day 7, all tested doses of rhuGM- CSF resulted in an increase in the absolute monocyte count (AMC) compared with placebo-treated neonates. In those receiving rhuGM-CSF 5.0 micrograms/kg twice per day, there was additionally a significant increase in the day 7 and 8 platelet count. Tibial bone marrow aspirates demonstrated a significant increase in the bone marrow neutrophil storage pool (BM NSP) at 5.0 micrograms/kg twice per day and 10.0 micrograms/kg once per day. Neutrophil C3bi receptor expression was significantly increased 24 hours after the first dose of rhuGM-CSF at 5.0 micrograms/kg once per day. The elimination half-life (T1/2) of rhuGM-CSF was 1.4 +/- 0.8 to 3.9 +/- 2.8 hours.(ABSTRACT TRUNCATED AT 400 WORDS)     

Early lymphocyte recovery predicts longer survival after autologous peripheral blood stem cell transplantation in multiple myeloma

To understand the prognostic value of lymphocyte recovery after autologous peripheral blood stem cell transplantation (APBSCT), we performed a retrospective study of 59 newly diagnosed multiple myeloma (MM) patients who underwent frontline APBSCT. Conditioning regimens were melphalan 100 mg/m(2) for 2 days. Following APBSCT, all patients showed complete or partial response. Median follow-up time was 29.57 months and median recovery of absolute lymphocyte count (ALC) > or =1000/mm(3) was 23 days. Univariate analysis revealed that significant predictors of overall survival (OS) included bone marrow (BM) plasma cells < or =40% at diagnosis (P=0.0243) and recovery of ALC > or =1000/mm(3) by day +23 (P=0.0156). Positive predictors for progression-free survival (PFS) were BM plasma cells < or =40% at diagnosis (P=0.0134) and recovery of ALC > or =1000/mm(3) by day +23 (P=0.0243). Absolute neutrophil count > or =1000/mm(3) on day +12 was marginally significant for OS and PFS (P=0.0821 and P=0.1153, respectively). Multivariate analysis showed that ALC > or =1000/mm(3) on day +23 independently predicted OS (P=0.031) and prolonged PFS (P=0.011), and that serum beta2-microglobulin was marginally significant for prolonged OS (P=0.066). In conclusion, ALC recovery was an independent predictor of both OS and PFS in MM.     

Hematopoietic growth factors for graft failure after bone marrow transplantation: a randomized trial of granulocyte-macrophage colony- stimulating factor (GM-CSF) versus sequential GM-CSF plus granulocyte- CSF

Delay in hematologic recovery after bone marrow transplantation (BMT) can extend and amplify the risks of infection and hemorrhage, compromise patients' survival, and increase the duration and cost of hospitalization. Because current studies suggest that granulocyte- macrophage (GM) colony-stimulating factor (CSF) may potentiate the sensitivity of hematopoietic progenitor cells to G-CSF, we performed a prospective, randomized trial comparing GM-CSF (250 micrograms/m2/d x 14 days) versus sequential GM-CSF x 7 days followed by G-CSF (5 micrograms/kg/d x 7 days) as treatment for primary or secondary graft failure after BMT. Eligibility criteria included failure to achieve a white blood cell (WBC) count > or = 100/microL by day +21 or > or = 300/microL by day +28, no absolute neutrophil count (ANC) > or = 200/microL by day +28, or secondary sustained neutropenia after initial engraftment. Forty-seven patients were enrolled: 23 received GM-CSF (10 unrelated, 8 related allogeneic, and 5 autologous), and 24 received GM- CSF followed by G-CSF (12 unrelated, 7 related allogeneic, and 5 autologous). For patients receiving GM-CSF alone, neutrophil recovery (ANC > or = 500/microL) occurred between 2 and 61 days (median, 8 days) after therapy, while those receiving GM-CSF+G-CSF recovered at a similar rate of 1 to 36 days (median, 6 days; P = .39). Recovery to red blood cell (RBC) transfusion independence was slow, occurring 6 to 250 days (median, 35 days) after enrollment with no significant difference between the two treatment groups (GM-CSF: median, 30 days; GM-CSF+G- CSF; median, 42 days; P = .24). Similarly, platelet transfusion independence was delayed until 4 to 249 days (median, 32 days) after enrollment, with no difference between the two treatment groups (GM- CSF: median, 28 days; GM-CSF+G-CSF: median, 42 days; P = .38). Recovery times were not different between patients with unrelated donors and those with related donors or autologous transplant recipients. Survival at 100 days after enrollment was superior after treatment with GM-CSF alone. Only 1 of 23 patients treated with GM-CSF died versus 7 of 24 treated with GM-CSF+G-CSF who died 16 to 84 days (median, 38 days) after enrollment, yielding Kaplan-Meier 100-day survival estimates of 96% +/- 8% for GM-CSF versus 71% +/- 18% for GM-CSF+G-CSF (P = .026). These data suggest that sequential growth factor therapy with GM-CSF followed by G-CSF offers no advantage over GM-CSF alone in accelerating trilineage hematopoiesis or preventing lethal complications in patients with poor graft function after BMT.(ABSTRACT TRUNCATED AT 400 WORDS)