Bendamustine, etoposide and dexamethasone to mobilize peripheral blood hematopoietic stem cells for autologous transplantation in patients with multiple myeloma.

Chemotherapeutic agents without cross-resistance to prior therapies may enhance PBSC collection and improve patient outcomes by exacting a more potent direct antitumor effect before autologous stem cell transplant. Bendamustine has broad clinical activity in transplantable lymphoid malignancies, but concern remains over the potential adverse impact of this combined alkylator-nucleoside analog on stem cell mobilization. We performed a prospective, nonrandomized phase II study including 34 patients with multiple myeloma (MM) (n=34; International Staging System (ISS) stages I (35%), II (29%) and III (24%); not scored (13%)) to evaluate bendamustine's efficacy and safety as a stem cell mobilizing agent. Patients received bendamustine (120 mg/m2 IV days 1, 2), etoposide (200 mg/m2 IV days 1-3) and dexamethasone (40 mg PO days 1- 4) (bendamustine, etoposide and dexamethasone (BED)) followed by filgrastim (10 µg/kg/day SC; through collection). All patients (100%) successfully yielded stem cells (median of 21.60 × 106/kg of body weight; range 9.24-55.5 × 106/kg), and 88% required a single apheresis. Six nonhematologic serious adverse events were observed in 6 patients including: neutropenic fever (1, grade 3), bone pain (1, grade 3) and renal insufficiency (1, grade 1). In conclusion, BED safely and effectively mobilizes hematopoietic stem cells.

A randomized study of melphalan 200 mg/m(2) vs 280 mg/m(2) as a preparative regimen for patients with multiple myeloma undergoing auto-SCT.

We aimed to examine whether doses of melphalan higher than 200 mg/m(2) improve response rates when used as conditioning before autologous transplant (ASCT) in multiple myeloma (MM) patients. Patients with MM, n=131, were randomized to 200 mg/m(2) (mel200) vs 280 mg/m(2) (mel280) using amifostine pretreatment. The primary end point was the proportion of patients achieving near complete response (⩾nCR). No treatment-related deaths occurred in this study. Responses following ASCT were for mel200 vs mel280, respectively, ⩾nCR 22 vs 39%, P=0.03, ⩾PR 57 vs 74%, P=0.04. The hazard of mortality was not statistically significantly different between groups (mel200 vs mel280; hazard ratio (HR)=1.15 (95% confidence interval (CI), 0.62-2.13, P=0.66)) nor was the rate of progression/mortality (HR=0.81 (0.52-1.27, P=0.36)). The estimated PFS at 1 and 3 years were 83 and 46%, respectively, for mel200 and 78 and 54%, respectively, for mel280. Amifostine and mel280 were well tolerated, with no grade 4 regimen-related toxicities and only one grade 3 mucositis (none with mel200) and three grade 3 gastrointestinal (GI) toxicities (two in mel200). Hospitalization rates were more frequent in the mel280 group (59 vs 43%, P=0.08). Mel280 resulted in a higher major response rate (CR+nCR) and should be evaluated in larger studies.

Maintenance rituximab after autologous stem cell transplantation in patients with mantle cell lymphoma.

BACKGROUND: High-dose therapy and autologous stem cell transplantation (ASCT) improves outcomes for patients with mantle cell lymphoma (MCL), but relapse ultimately occurs in most patients. Recently presented interim results from a phase III prospective trial suggest maintenance rituximab (MR) after ASCT for MCL improves progression-free survival (PFS). The maturation of these data and any benefit of MR on overall survival (OS) remain to be defined. PATIENTS AND METHODS: In this retrospective study, we examined a cohort of consecutive patients with MCL that underwent ASCT for MCL at our center and evaluated their outcomes according to whether they received MR after ASCT (n = 50) or did not (n = 107). MR was treated as a time-dependent covariate to account for variation in timing of its initiation. RESULTS: MR was associated with an improved PFS [hazard ratio (HR) 0.44; confidence interval (CI) (0.24-0.80), P = 0.007] and overall survival (OS; HR 0.46; CI 0.23-0.93, P = 0.03) following a multivariate adjustment for confounding factors with a median follow-up of ∼5 years. Grade 4 neutropenia was increased (34% versus 18%, P = 0.04) in the MR group, but no effect on the rate of mortality unrelated to relapse was observed. CONCLUSIONS: These data support that MR after ASCT for MCL confers a benefit in PFS and additionally suggest it may improve OS. General application of this strategy will require confirmation of benefit in prospective randomized trials.

Utilization of stored autologous PBSCs to support second autologous transplantation in multiple myeloma patients in the era of novel agent therapy.

Outcomes in multiple myeloma (MM) have improved significantly with novel agent therapy and autologous stem cell transplantation (ASCT). ASCTs are typically planned as either tandem or a single transplant with additional stored PBSCs available for a second salvage transplant. To accommodate these strategies, many centers routinely collect and store adequate PBSCs for two ASCTs. We analyzed the cost associated with this practice by determining the expenses of PBSC collection, cryopreservation and storage, and the ultimate use of additional cryopreserved PBSCs in patients who had undergone at least one ASCT. There were 889 MM patients transplanted between 1993 and 2011 at our center. Most (N=726) had residual PBSCs in storage after their first ASCT (ASCT1). Only 135 patients underwent a second ASCT within a median of 14 months after ASCT1. The percentage of patients receiving a second ASCT declined over time. The resources required to collect and store unused PBSCs added up to 336 extra patient days of apheresis and 41 587 extra patient months of cryopreservation, translating into an average extra cost per patient of US$4981.12. A reconsideration of conventional PBSC collection and storage practices would save significant cost for the majority of MM patients who never undergo a second ASCT.

Modified high-dose melphalan and autologous SCT for AL amyloidosis or high-risk myeloma: analysis of SWOG trial S0115.

We designed a trial using two sequential cycles of modified high-dose melphalan at 100 mg/m(2) and autologous SCT (mHDM/SCT) in AL amyloidosis (light-chain amyloidosis, AL), AL with myeloma (ALM) and host-based high-risk myeloma (hM) patients through SWOG-0115. The primary objective was to evaluate OS. From 2004 to 2010, 93 eligible patients were enrolled at 17 centers in the United States (59 with AL, 9 with ALM and 25 with hM). The median OS for patients with AL and ALM was 68 months and 47 months, respectively, and has not been reached for patients with hM. The median PFS for patients with AL and ALM was 38 months and 16 months, respectively, and has not been reached for patients with hM. The treatment-related mortality (TRM) was 12% (11/93) and was observed only in patients with AL after SCT. Grade 3 and higher non-hematologic adverse events were experienced by 81%, 67% and 57% of patients with AL, ALM and hM, respectively, during the first and second HDM/SCT. This experience demonstrates that with careful selection of patients and use of mHDM for SCT in patients with AL, ALM and hM, even in the setting of a multicenter study, OS can be improved with acceptable TRM and morbidity.

The impact of histologic grade on the outcome of high-dose therapy and autologous stem cell transplantation for follicular lymphoma.

The impact of the follicular lymphoma (FL) histologic grade on outcomes after high-dose therapy (HDT) and autologous stem cell transplantation (ASCT) is unknown. We evaluated 219 consecutive patients with grades 1-3 FL who underwent HDT and ASCT at our center. Overall survival (OS), progression-free survival (PFS), relapse and non-relapse mortality (NRM) was estimated for each grade after controlling for other predictive factors. The number of patients with grades 1, 2 and 3 FL was 106 (48%), 75 (34%) and 38 (17%), respectively. Five-year outcome estimates for the entire cohort included 60% OS, 39% PFS and 46% relapse (median follow-up=7.8 years). PFS and relapse were nearly identical among patients with grade 3 FL versus grades 1-2 FL after adjusting for other contributing factors (hazard ratio (HR)=0.90, P=0.68; HR=1.07, P=0.80, respectively). The hazard for mortality (HR=0.70, P=0.23) and NRM (HR=0.33, P=0.07) was non-significantly lower among patients with grade 3 FL compared to patients with grades 1-2 disease. Factors associated with inferior PFS included elevated lactate dehydrogenase (HR=1.52, P=0.03), chemoresistance (HR=1.82, P=0.02), > or =2 prior therapies (HR=1.8, P=0.03) and prior radiation (HR=1.99, P=0.003). These data suggest that the histologic grade of FL does not impact PFS or relapse following HDT and ASCT.

Theratope vaccine (STn-KLH).

Active specific immunotherapy (ASI) is a promising approach to treating cancer. Numerous studies in the laboratory have demonstrated that various cancer vaccines can stimulate antibody and cell mediated immune responses against tumour-associated antigens [1-9]. Yet few studies have demonstrated convincing clinical responses. Sialyl-Tn (STn) is a carbohydrate associated with the MUC1 mucin on a number of human cancer cells and is associated with more aggressive disease. Consequently, STn is an ideal candidate for ASI therapy. Theratope vaccine is a cancer vaccine that was designed by Biomira, Inc. (Edmonton, Alberta, Canada) by incorporating a synthetic STn antigen that emulates the carbohydrate seen on human tumours. The clinical trials conducted to date with Theratope vaccine are outlined in this report. Overall, Theratope vaccine has been well-tolerated with minimal toxicity. The most common side effects have been in duration and erythema at the site of injections. Both in a non-transplant setting following low dose iv. cyclophosphamide and high dose autologous transplant setting, there has been a trend toward Theratope vaccine decreasing the risk for relapse, prolonging the time to relapse and thus impacting on overall survival. The definitive Phase III trial comparing the outcome of patients with metastatic breast cancer receiving vaccinations with Theratope vaccine versus vaccination with the nonspecific immune stimulants Keyhole Limpet Hemocyanin (KLH) and Detox -B stable emulsion (Detox-B) (now called Enhanzyn Immunostimulant) was closed to enrolment on March 30, 2001. Over 1000 women with distant metastatic breast cancer were enrolled into the program.

Autologous stem cell transplantation for non-Hodgkin's lymphoma: comparison of radiation-based and chemotherapy-only preparative regimens.

The aim of this study was to compare toxicity and efficacy of total body irradiation (TBI), cyclophosphamide (CY) and etoposide (E) (TBI/CY/E) vs busulfan, melphalan and thiotepa (Bu/Mel/T) in patients receiving autologous stem cell infusion (ASCI) for malignant lymphoma (NHL). Between September 1990 and July 1998, 351 patients with NHL were treated with TBI/CY/E (n = 221) or Bu/Mel/T (n = 130) followed by ASCI. Patients in first, or second remission, first responding or untreated relapse were defined as having less advanced disease before transplantation. The median follow-up was 5 years (range 1-9) and 3.5 years (1-6) for patients receiving TBI/CY/E and Bu/Mel/T, respectively. The cumulative probabilities of survival, event-free survival (EFS) and relapse at 5 years were 44%, 32%, 49% following TBI/CY/E and 42%, 34% and 42% following Bu/Mel/T. The probability of EFS at 5 years for patients who had prior dose-limiting radiation (n = 59) was 32% after Bu/Mel/T therapy. Transplant-related mortality was 16% for TBI/CY/E and 21% for Bu/Mel/T. In univariate and multivariate analyses, more advanced disease status was associated with poor outcome (TBI/CY/E: RR 0.70, CI 0.50 to 0.97 P = 0.04; Bu/Mel/T: RR 0.61, CI 0.39 to 0.97 P = 0.03). No significant differences in toxicities and outcomes were observed between these two regimens despite the inclusion of patients who had received dose-limiting irradiation in the Bu/Mel/T regimen.

High-dose busulfan, melphalan and thiotepa as consolidation for non-inflammatory high-risk breast cancer.

The purpose of this study was to evaluate the toxicity and efficacy of high-dose busulfan, melphalan and thiotepa (Bu/Mel/TT) in patients with high-risk non-inflammatory breast cancer defined as stage II disease > or =10 lymph nodes (n = 52) or stage III (n = 69), and prognostic factors for treatment outcome. One hundred and twenty-one patients (median age, 46 years) were treated with high-dose Bu (12 mg/kg), Mel (100 mg/m2) and TT (500 mg/m2) (HDC) followed by autologous stem cell infusion (ASCI). One hundred patients were initially treated with surgery followed by standard adjuvant chemotherapy prior to HDC/ASCI. Twenty-one patients with stage III disease had inoperable tumors at diagnosis and were treated with neoadjuvant chemotherapy and surgery before HDC/ASCI. Transplant-related mortality was 6%. The probabilities of event-free survival (EFS) at 3 and 5 years (median follow-up of 36 months) from transplant were, for all patients: 0.62-0.60; stage II: 0.71-0.67: stage III: 0.55-0.55 (for stage III adjuvant and neoadjuvant groups: 0.60-0.60 and 0.42-0.42, respectively). Multivariate analysis did not identify variables associated with poor outcome. The efficacy of Bu/Mel/TT is similar to other HDC regimens reported for patients with high-risk non-inflammatory breast cancer. Bu/Mel/TT has high activity in stage II disease and a moderate benefit in stage III operable tumors.

Enumeration of HPC in mobilized peripheral blood with the Sysmex SE9500 predicts final CD34+ cell yield in the apheresis collection.

Enumeration of CD34+ cells in the peripheral blood before apheresis predicts the quantity of those cells collected, although the cytometric techniques used are complex and expensive. We found that a subpopulation of lysis-resistant cells in the peripheral blood, identified by the Sysmex SE9500 and designated as HPC, can serve as a surrogate marker predictive of the yield of CD34+ cells. Spearman's rank statistics were used to examine the correlation between WBC, MNC, HPC and CD34+ cells in the peripheral blood and final CD34+ cell yield for 112 samples of peripheral blood and matching apheresis collections from 66 patients and donors. The results indicate that WBC and MNC in the peripheral blood were poor predictors of CD34 content, while HPC gave a correlation coefficient of 0.62. The positive predictive values of different cutoff levels of HPC in the peripheral blood ranging from 5 to 50 x 106/l increased from 0.80 to 0.93 when the target collection was 1 x 106cells/kg. However, for patients with HPC levels below various cutoff levels, the proportion of the collections not reaching that target goal ranged between 0.36 and 0.43, indicating that most collections will still exceed the target goal of CD34+ cells. When the target collection was 2.5 x 106 CD34+ cells/kg, the positive predictive value was lower and negative predictive value was higher.

Clinical outcome of breast and ovarian cancer patients treated with high-dose chemotherapy, autologous stem cell rescue and THERATOPE STn-KLH cancer vaccine.

The purpose of this study was to evaluate the toxicity and potential efficacy of administering the THERATOPE STn-KLH cancer vaccine to ovarian and breast cancer patients after an autologous stem cell transplant. Forty patients (11 high-risk stage II/III breast cancer, 22 stage IV breast cancer, and seven stage III/IV ovarian cancer patients) were treated with high-dose chemotherapy followed by autologous/syngeneic stem cell rescue and vaccination with THERATOPE STn-KLH (Sialyl-Tn-KLH with Detox-B Stable Emulsion). Each patient was scheduled to receive a total of five vaccinations beginning on days 30-151 after stem cell infusion. The vaccine was well tolerated. Induration and erythema at the site of injection were the most common side-effects. When one compares the outcome of patients vaccinated with 66 breast and ovarian cancer patients who were not, following risk-adjustment analysis, vaccinated patients appeared more likely to survive (P = 0.07) and less likely to relapse (P = 0. 10). Vaccinated patients with the greatest specific lytic activity against STn+OVCAR tumor cells relative to nonspecific killing of Daudi cells tended to remain in remission longer than patients who displayed less specific immune activity (P = 0.057). We conclude that the THERATOPE STn-KLH cancer vaccine is well tolerated in breast and ovarian cancer patients after autologous transplant and, while not statistically significant, the trends in data support the concept that THERATOPE vaccine may decrease the risk for relapse and death and thus warrants further study. Bone Marrow Transplantation (2000) 25, 1233-1241.

Increased incidence of cytomegalovirus disease after autologous CD34-selected peripheral blood stem cell transplantation.

High-dose therapy with autologous peripheral blood stem cell (PBSC) rescue is widely used for the treatment of malignant disease. CD34 selection of PBSC has been applied as a means of reducing contamination of the graft. Although CD34 selection results in a 2 to 3 log reduction in contaminating tumor cells without significantly delaying engraftment, many other types of cells are depleted from the CD34-enriched grafts and immune reconstitution may be impaired. In the present study, 31 cytomegalovirus (CMV)-seropositive patients who received myeloablative therapy followed by the infusion of CD34-selected autologous PBSC were assessed for the development of CMV disease in the first 100 days posttransplant. Seven patients (22.6%) developed CMV disease and 4 patients (12.9%) died from complications of their infection. In a contemporaneous group of 237 CMV-seropositive patients receiving unselected, autologous PBSC, only 10 patients (4.2%) developed CMV disease, with 5 deaths (2.1%). In a multivariate logistic regression analysis, the use of CD34-selected autologous PBSC after high-dose therapy was associated with a marked increase in the incidence of CMV disease and CMV-associated deaths.

The predictive value of white cell or CD34+ cell count in the peripheral blood for timing apheresis and maximizing yield.

BACKGROUND: The collection of peripheral blood stem and progenitor cells (PBPCs) for transplantation can be time-consuming and expensive. Thus, the utility of counting CD34+ cells and white cells (WBCs) in the peripheral blood was evaluated as a predictor of CD34+ cell yield in the apheresis component. STUDY DESIGN AND METHODS: The WBC and CD34+ cell counts in the peripheral blood and the apheresis components from 216 collections were assessed. Sixty-three patients underwent mobilization with chemotherapy plus filgrastim, and 17 patients and 14 allogeneic PBPC donors did so with filgrastim alone. The relationship between the number of WBC and CD34+ cells in the peripheral blood and in the apheresis component was analyzed by using rank correlation and linear regression analysis. RESULTS: The correlation coefficient for CD34+ cells per liter of peripheral blood with CD34+ cell yield (x 10(6)/kg) was 0.87 (n = 216 collections). This correlation existed for many patient and collection variables. However, patients with acute myeloid leukemia had fewer CD34+ cells in the apheresis component at any level of peripheral blood CD34+ cell count. Components collected from patients with CD34+ cell counts below 10 x 10(6) per L in the peripheral blood contained a median of 0.75 x 10(6) CD34+ cells per kg. When the WBC count in the blood was below 5.0 x 10(9) per L, the median number of CD34+ cells in the peripheral blood was 5.6 x 10(6) per L (range, 1.0-15.5 x 10(6)/L). A very poor correlation was found between the WBC count in the blood and the CD34+ cell yield (p = 0.12, n = 158 collections). CONCLUSION: The number of CD34+ cells, but not WBCs, in the peripheral blood can be used as a predictor for timing of apheresis and estimating PBPC yield. This is a robust relationship not affected by a variety of patient and collection factors except the diagnosis of acute myeloid leukemia. Patients who undergo mobilization with chemotherapy and filgrastim also should undergo monitoring of peripheral blood CD34+ cell counts, beginning when the WBC count in the blood exceeds 1.0 to 5.0 x 10(9) per L.

Evidence of a cellular immune response against sialyl-Tn in breast and ovarian cancer patients after high-dose chemotherapy, stem cell rescue, and immunization with Theratope STn-KLH cancer vaccine.

Seven ovarian and 33 breast high-risk stage II/III and stage IV cancer patients received high-dose chemotherapy followed by stem cell rescue. Thirty to 151 days after stem cell transplantation, the patients received their first immunotherapy treatment with Theratope STn-KLH cancer vaccine. Most patients developed increasing IgG anti-STn titers to a sustained peak after the fourth or fifth immunizations. Only one patient had elevated CA27.29 (MUC1 mucin) serum levels at trial entry. Five of the seven patients with preimmunotherapy elevated serum CA125 levels demonstrated decreasing CA125 levels during immunotherapy, consistent with an antitumor response. Evidence of STn antigen-specific T-cell proliferation was obtained from 17 of the 27 evaluable patients who received at least three immunotherapy treatments. Eleven of the 26 patients tested had evidence of an anti-STn TH1 antigen-specific T-cell response as determined by interferon-gamma, but not interleukin (IL)-4, production. After immunization, lytic activity of peripheral blood lymphocytes (PBLs) tested against a lymphokine activated killer (LAK)-sensitive cell line, a natural killer (NK)-sensitive cell line, and an STn-expressing cancer cell line (OVCAR) increased significantly. In vitro IL-2 treatment of the PBLs after vaccination greatly enhanced killing of the STn+ cancer cell line. Evidence of the development of OVCAR specific killing activity, over and above that seen due to LAK or NK killing, is presented. These studies provide the strongest evidence in humans of the development of an antitumor T-cell response after immunization with a cancer-associated carbohydrate antigen.

High-dose busulfan, melphalan and thiotepa followed by autologous peripheral blood stem cell (PBSC) rescue in patients with advanced stage III/IV ovarian cancer.

The purpose of this study was to evaluate the efficacy of high-dose chemotherapy (HDC) with busulfan, melphalan and thiotepa (BUMELTT) followed by autologous PBSC infusion in treating patients with advanced ovarian cancer. Thirty-one patients, 18 with stage III/IIIc and 13 with stage IV ovarian cancer, were treated with BU (12 mg/kg), MEL (100 mg/m2) and TT (500 mg/m2) and autologous PBSC rescue. Fifteen patients were in clinical complete remission (CR) at treatment; 11 had platinum-sensitive disease. Sixteen patients were not in CR; two had platinum-sensitive disease. The probabilities of overall survival (OS), event-free survival (EFS) and relapse (R) for all patients at 18 months were 0.57, 0.30 and 0.63; for patients in CR, the rates were 0.87, 0.44 and 0.49 and for patients not in CR, 0.38, 0.13 and 0.81. Two patients (6.5%) died of treatment-related causes. Among the 13 patients with platinum-sensitive disease, all are still alive, with seven having relapsed 129-1021 days after PBSC infusion. OS, EFS and R were 1.00, 0.52 and 0.48. Of the 18 patients with platinum-resistant disease, four remain alive (two in remission). Six patients did not respond and eight relapsed from days 104-429. The OS, EFS and R were 0.33, 0.11 and 0.78. We conclude that BUMELTT is well tolerated in patients with advanced ovarian cancer and results are equivalent to other published HDC regimens.

High-dose fractionated total-body irradiation, etoposide and cyclophosphamide for treatment of malignant lymphoma: comparison of autologous bone marrow and peripheral blood stem cells.

Consecutive patients with non-Hodgkin's lymphoma (NHL, n = 133) or Hodgkin's disease (HD, n = 20) were treated with 12.0 Gy of fractionated total body irradiation, etoposide 60 mg/kg, and CY 100 mg/kg followed by infusion of autologous hematopoietic stem cells. Seventy-nine patients received purged (n = 62) or unpurged BM (n = 17), and 74 received unpurged PBSCs alone (n = 56) or with BM (n = 18). The median day for achieving a sustained granulocyte count of 0.5 x 10(9)/I was 14 range (7-66) for BM recipients and 10 (7-30) for PBSC +/- BM recipients (P = 0.03). A platelet count of 20 x 10(9)/I was achieved at a median of day 24 (6-145) in BM recipients and day 11 (range, 7-56) in PBSC +/- BM recipients (P = 0.007). The median number of platelet units transfused was 86 (0-1432) for BM recipients and 30 (6-786) for PBSC +/- BM recipients (P = 0.001). The median number of hospital days was 36 (10-88) for BM recipients and 27 (14-76) for PBSC +/- BM recipients (P = 0.0001). The unadjusted Kaplan-Meier (KM) estimates of survival, event-free survival (EFS) and relapse at 2 years were 0.57, 0.45 and 0.43 for patients receiving BM and 0.55, 0.36 and 0.59 for patients receiving PBSC +/- BM. After adjusting for confounding variables, the estimated relative risk (RR) of death from any cause was 0.92 (P = 0.75), of relapse was 1.25 (P = 0.39), of non-relapse mortality was 0.71 (P = 0.42) and of mortality and/or relapse was 1.17 (P = 0.48) for patients receiving PBSC +/- BM as compared to BM. For 46 patients with NHL receiving unpurged PBSC alone, the unadjusted KM estimate of relapse was 0.61 compared with 0.48 for 52 comparable patients receiving purged BM, while the RR for relapse for patients receiving unpurged PBSCs was 1.37 (P = 0.33) after adjusting for other significant covariates. These data confirm previous observations that patients who receive PBSC +/- BM have faster engraftment, fewer transfusions and shorter hospital stays than patients who receive only BM. There were no statistically significant differences between the two groups in survival, relapse, death from causes other than relapse and event-free survival.

Aplastic anemia: analysis of stromal cell function in long-term marrow cultures.

Marrow samples from 89 patients with aplastic anemia (AA) were evaluated for their ability to grow stromal layers in standard long-term marrow cultures (LTMCs). Results were highly variable: 6.8% failed to grow any stromal cells (group I); 42.5% either failed to grow to confluency or appeared to have a decreased number of adipocytes and/or macrophages (group II); and 52.8% appeared as normal confluent cultures with fibroblasts, adipocytes, and macrophages (group III). Analyses of patient data suggested that group I patients had a longer disease duration and poorer survival (P = .07). Enzyme-linked immunosorbent assay analysis of cytokine production was performed on 20 of the normal-appearing AA LTMCs and 12 LTMCs established from normal donors. Significant differences between the AA and control groups were apparent for macrophage inflammatory protein-1 alpha (MIP-1 alpha), interleukin-1 receptor antagonist (IL-1ra), granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), and leukemia-inhibitory factor (LIF). The most dramatic differences observed were elevated levels of MIP-1 alpha and GM-CSF and decreased levels of IL-1ra, particularly after IL-1 alpha stimulation. In contrast, IL-1 alpha stimulation of AA LTMCs produced levels of IL-6, LIF, and G-CSF comparable with those of controls. These data suggest that defects exist within the microenvironment of some AA marrows. Whether the majority of these defects are the cause or consequence of aplasia is not clear. However, we speculate that some of these abnormalities may contribute to the maintenance of the hypoplastic state and, in extreme cases, prevent engraftment of donor marrow.

The effect of natural killer cells on the development of syngeneic hematopoietic progenitors.

To determine whether natural killer (NK) cells are involved in the regulation of hematopoiesis, well-characterized, cell sorter-purified NK cells were incubated with syngeneic bone marrow, and the effect of this interaction on the development of various hematopoietic progenitors was assessed. NK cells were obtained from the peritoneal exudates of CBA/J mice after i.p. infection with live Listeria monocytogenes (LM). These NK cells were nylon wool-nonadherent and were purified by using M1/70, a rat anti-murine macrophage monoclonal antibody, and a fluorescence-activated cell sorter (FACS). Syngeneic bone marrow was incubated overnight with these M1/70-purified NK cells. The cells were then assayed in vitro to determine the effect on the colony formation of the following hematopoietic progenitor cells: the myeloid progenitor that produces mixed granulocyte/macrophage colonies (CFU-G/M), the myeloid progenitor that is committed to macrophage differentiation (CFU-M), and the early erythroid progenitor that is known as the burst-forming unit-erythroid (BFU-E). The marrow cells, after incubation with NK cells, were also injected into lethally irradiated syngeneic recipients to assay for the splenic colony formation capacity of the trilineage myeloid stem cell (CFU-S). Although the formation of BFU-E-, CFU-G/M-, and CFU-M-derived colonies was not adversely affected by the exposure of syngeneic bone marrow to purified NK cells, there was a dramatic decrease in the number of CFU-S-derived colonies. Incubation with NK-depleted cells did not result in an inhibition of colony formation by the CFU-S. Mixing experiments showed that the M1/70-labeled NK cells exerted their effect directly on the CFU-S and not on any accessory cells. The effect of the NK cells on colony formation by the CFU-S could be blocked competitively and selectively by the addition, before incubation, of a classic murine NK tumor target, Yac-1. Another tumor line (WTS) that is poorly recognized by NK cells was less effective in blocking the inhibitory effect of NK cells on CFU-S. The demonstration that purified NK cells can selectively inhibit the development of the tripotential CFU-S may point to the importance of NK cells in the regulation of hematopoiesis, in the development of some types of marrow dysfunction, and in the failure of engraftment of transplanted bone marrow.

Characterization of natural killer cells induced in the peritoneal exudates of mice infected with Listeria monocytogenes: a study of their tumor target specificity and their expression of murine differentiation antigens and human NK-associated antigens.

That M1/70, a monoclonal anti-murine macrophage antibody, recognizes murine natural killer cells (NK) and that there is an increase in NK following intraperitoneal infection with live Listeria monocytogenes (LM) was previously reported. Here, LM-induced NK cells were further characterized with respect to tumor target specificity and the expression of murine mast cell, mononuclear phagocyte, and lymphocyte differentiation antigens plus human NK-associated antigens. The M1/70-selected NK (Mac 1 NK) lysed Yac 1, RLmale 1, and WEHI 164.1, but not EL 4 or WTS cells. Immunoprecipitation with M1/70 demonstrated that Mac 1, the antigen recognized by M1/70, was present on NK and thioglycollate-elicited macrophages. Contaminating macrophages in the NK-enriched population did not account for the immunoprecipitated Mac 1. Mac 1 NK that lysed Yac 1 displayed Qa 5, LFA 1, asialo GM 1, Ly 5.1, and NK 1.2, but not Lyt 1, Lyt 2, Mac 2, Mac 3, or Mac 4. Thirty percent of these Mac 1 NK bore Thy 1.2. The presence of Thy 1.2 did not correlate with individual lytic efficiency or cell cycle. Antibodies to human NK antigens Leu 7, Leu 11a, and Leu 15 did not recognize LM-induced NK cells.