Monitoring anti-thymocyte globulin (ATG) in bone marrow recipients

The present study was undertaken to acquire a rationale for clinical dose adjustment of anti-thymocyte globulin (ATG) to improve cost effectiveness and safety of graft-versus-host disease prophylaxis. The concentration of rabbit ATG in the serum of 12 patients was measured by ELISA and by the inhibitory effect on phytohaemagglutinin-induced blastogenesis. At 10 mg/ml ATG, 3H-thymidine incorporation was effectively blocked. Serial two-fold dilution of ATG showed that this effect decreased in a concentration-dependent manner and was lost at 10 ng/ml ATG. One hundred microlitres serum taken at day -1 to +22 post transplant effected significant inhibition of the phytohaemagglutinin-response with 49+/-12% c.p.m. (x +/- s.d.) on day +1 post transplant compared to 93+/-13% c.p.m. on day -1 (P<0.001, unpaired one-sided t-test). The rabbit-IgG was maximal at a concentration of 907+/-187 microl/ml at day 0. Subsequently, it decreased with time. While rabbit-IgG was detectable for a long period (e.g. 160 microg/ml at day +22 in patient MD), the effect on the phytohaemagglutinin-response of normal mononuclear cells lasted up to 4 days post transplant. We conclude that 90 mg/kg body weight ATG-Fresenius given prior to marrow transplant leads to sustained T cell immunosuppression post transplant.

Tumour cell detection in G-CSF mobilised stem cell harvests of patients with breast cancer

Peripheral blood stem cells were mobilised with G-CSF from steady-state haemopoiesis after previous anthracyclin-containing standard dose chemotherapy in patients with high-risk breast cancer. 48 samples were obtained from patients with stage II-III breast cancer and > or = 10 lymph nodes, 15 samples from patients with chemotherapy sensitive metastatic disease, and 13 samples from women with inflammatory breast cancer. 44 samples were first or single leukaphereses and 32 samples were second or third harvests. Aliquots were searched for contaminating tumour cells by immunocytochemistry (IC) and cytokeratin-19 reverse transcriptase polymerase chain reaction rtPCR). The median count of MNCs examined by IC was 2 x 10(6); cDNA prepared from 2 x 10(7) cells was subjected to PCR. Fifty-nine samples were examined by immunocytochemistry, 36 samples by rtPCR, and 19 samples by both techniques. Samples investigated by IC and rtPCR were judged as positive if there was at least one positive test. On the whole, 42/79 (55.3%) of the samples were positive with an insignificant trend to a higher positivity rate in second or subsequent leukaphereses (52.3% vs 59.3%). The median tumour cell load per 10(6) MNCs was low with 0.5 (0-7) cells in all, and a total of 2.2 (0.5-7) cells in positive specimen. Differences in the cancer cell load of first and subsequent leukaphereses and between subgroups of patients were not found. PCR and IC gave consistent results in 63.2%. This phenomenon can be explained by the greater sensitivity of the molecular method and by a Poisson distribution of coharvested tumour cells in samples. Tumour cell contamination in G-CSF mobilised stem cells from patients with breast cancer from steady state haemopoiesis after preceding anthacyclin-containing chemotherapy is frequent, but the tumour cell load is low. To allow a comparison of different studies dealing with cancer cell contamination in stem cells, standardisation of assays is necessary.

Early infections in patients undergoing bone marrow or blood stem cell transplantation--a 7 year single centre investigation of 409 cases

Infections are a major cause of morbidity and mortality in patients undergoing high-dose therapy and subsequent autologous or allogeneic haemopoietic stem cell transplantation, despite the change from topical to systemic anti-infection prophylaxis and the introduction of growth factors and new antimicrobial drugs. We report our single centre experience with data from 409 patients treated at our unit from its opening in 1990 until May 1997. Three hundred and seventy-eight patients were transplanted for the first time, 12 patients were retransplanted or boosted and 19 patients were readmitted for miscellaneous reasons. 245 patients were allografted and 157 autografted. Antimicrobial prophylaxis was mainly quinolones, fluconazole plus amphotericin-B orally, aciclovir, and TMP/SMX or pentamidine. Three hundred and nineteen (78%) developed fever of significantly longer duration in the allogeneic setting with anti-CMV seropositivity. The most frequent infection was fever of unknown origin (50.6%), followed by septicaemia (12.5%) and pneumonia (11.0%). Pathogens isolated in 24.6% of the infections were mostly gram-positive bacteria (57.9%), followed by non-fermenting rods (11.2%), Aspergillus spp. and Candida spp. (10.3%, each). Cumulative response rate to antimicrobial therapy was 66.9%. Infections were responsible for 62.5% (25/40) of deaths after transplantation. Predominant pathogens were Aspergillus spp. (11), Candida spp. (four), and Pseudomonas spp. (three). None of the patients died from gram-positive bacterial infection. The risk of dying from infection was 11.2% after allografting and 0.8% after autotransplantation. Infections remain a major risk for early death after allogeneic transplantation of haemopoietic stem cells. Infection with gram-negative bacteria can be prevented by quinolone prophylaxis. Predominant pathogens are Aspergillus spp. Candida spp. and nonfermenting rods. Systemic infection with these pathogens is associated with a poor prognosis. Antimycotic prophylaxis and the therapy must be improved.

Factors influencing platelet recovery after autologous transplantation of G-CSF-mobilized peripheral blood stem/progenitor cells following myeloablative therapy in 50 heavily pretreated lymphoma patients

Delayed platelet recovery following autologous PBPCs transplantation after myeloablative therapy remains an unresolved problem in lymphoma patients heavily pretreated with several chemotherapy cycles and/or radiotherapy. In the present study of 50 lymphoma patients, the factors influencing platelet recovery after myeloablative therapy followed by autologous PBPCs transplantation were analysed retrospectively. The median age was 42 years (range, 15-58). Fourteen patients had HD and 36 had NHL (13 high-grade and 23 low-grade); most (80%) had stage III or IV. Twenty-two patients had received radiotherapy to various extents before mobilization. The mean number of previous chemotherapy cycles was seven (range 3-24) of different regimens (range 1-4). A median of three leukapheresis procedures (range 1-5) was performed after G-CSF mobilization. Single leukapheresis was sufficient in only one patient. A significant correlation was found between the BFU-E content of autografts and platelet recovery after transplantation. Neither the patient's age and sex nor the stage and grade of lymphoma had any effect on platelet recovery after transplantation. Neither the type of myeloablative therapy used or the dose of G-CSF administered after transplantation had any effect on platelet recovery after transplantation. The type of previous chemotherapy cycles was a major adverse factor affecting the progenitor cell yield in the autografts. Lymphoma patients previously treated with ASHAP and/or Dexa-BEAM cycles had less progenitor cell yield. The chemotherapeutic agents used in previous cycles also had a clear adverse effect on the progenitor cell yield in the autografts. Lymphoma patients previously treated with cycles including cytarabine and/or cisplatin showed significantly less progenitor cell yield and slower platelet recovery after transplantation. All seven patients with delayed platelet recovery had received cytarabine and/or cisplatin in several previous ASHAP and/or Dexa-BEAM cycles. All seven patients had a BFU-E count of less than 1 x 10(5)/kg yield in the autografts.

Stem cell mobilization with G-CSF alone in breast cancer patients: higher progenitor cell yield by delivering divided doses (2 x 5 microg/kg) compared to a single dose (1 x 10 microg/kg)

We investigated the schedule dependency of G-CSF (10 microg/kg) alone in mobilizing peripheral blood progenitor cells (PBPC) in breast cancer patients. After a median of three cycles (range, 2-6) of anthracycline-based chemotherapy, 49 patients with breast cancer (stage II/III, > or = 10+ Ln n = 36; locally advanced/inflammatory n = 8, stage IV (NED) n = 5) underwent PBPC collection after steady-state mobilization either with 1 x 10 microg/kg (n = 27) or with 2 x 5 microg/kg (n = 22) G-CSF daily for 4 consecutive days until completion of apheresis. Apheresis was started on day 5. Priming with 2 x 5 microg/kg resulted in a higher median number of CD34+ cells (5.8 vs 1.9 x 10(6)/kg, P = 0.003), MNC (6.6 vs 2.6 x 10(8)/kg, P < 0.001) and CFU-GM (6.5 vs 1.3 x 10(4)/kg, P = 0.001) in the first apheresis than with 1 x 10 microg/kg. Also the overall number of collected BFU-E was higher in the 2 x 5 microg group (9.2 vs 3.1 x 10(4)/kg; P = 0.01). After high-dose chemotherapy with cyclophosphamide/thiotepa/mitoxantrone (n = 46) hematopoietic engraftment with leukocyte count > 1.0/nl was reached in both groups after a median of 10 days (range, 8-15) and with platelets count > 50/nl after 12 (range, 9-40) and 13 days (range, 12-41), respectively. A threshold of > 2.5 x 10(6)/kg reinfused CD34+ cells ensured rapid platelet engraftment (12 vs 17 days; P = 0.12). Therefore, the target of collecting > 2.5 x 10(6) CD34+ cells was achieved in 21/27 (80%) patients of the 1 x 10 microg group and in 21/22 (95%) patients of the 2 x 5 microg/kg group with a median of two aphereses (range, 1-4). None in the 10 microg/kg group, but 6/22 (28%) patients in the 2 x 5 microg/kg group required only one apheresis procedure, resulting in fewer apheresis procedures in the 2 x 5 microg/kg group (mean, 1.8 vs 2.3, P = 0.01). These results demonstrate that priming with 10 microg/kg G-CSF alone is well tolerated and effective in mobilizing sufficient numbers of CD34+ cells in breast cancer patients and provide prompt engraftment after CTM high-dose chemotherapy. G-CSF given 5 microg/kg twice daily (2 x 5 microg) leads to a higher harvest of CD34+ cells and required fewer apheresis procedures than when given 10 microg/kg once daily (1 x 10 microg).

Treatment of mycotic infections after haemopoietic progenitor cell transplantation with liposomal amphotericin-B

115 patients undergoing allogeneic or autologous bone marrow or peripheral blood stem cell transplantation were treated empirically or for documented fungal infection with liposomal amphotericin-B in doses up to 10mg/kg bodyweight for a duration up to 61 days. The therapy was excellent tolerated and clinical side effects occurred in only eight patients. The drug had to be withdrawn in one episode. A significant influence of liposomal amphotericin-B on laboratory parameters was not observed. Creatinine increased under therapy from a median base point of 1,0 (0,2-3,5) mg/dl to the upper normal value of 1,4 (0,4-4,2) mg/dl. Heavy increases of creatinine as well as of bilirubin, OT and PT were mostly associated with GvHD or regimen related toxicity. Considering the high-risk state of the patients the overall response rate was favourable with 62,9%. However, despite administration of liposomal amphotericin-B culture-proven mycoses were associated with a high morbidity (93,3%). Only one of fourteen patients was cured from Candida lambica septicaemia. We conclude that the antimycotic therapy with liposomal amphotericin-B has a low incidence of side effects. This should, considering the high mortality of fungal infections in BMT recipients, encourage investigators to perform dose escalating studies against the conventional formulation.

Intensified conditioning regimen in bone marrow transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia

We investigated an intensified conditioning regimen including fractionated total body irradiation (12 Gy), etoposide (30-45 mg/kg) and cyclophosphamide (120 mg/kg), followed by autologous (n = 5), allo-related (n = 13) or allo-unrelated (n = 6) bone marrow (n = 22) or peripheral stem cell (n = 2) transplantation in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia. One patient received busulfan (16 mg/kg) instead of TBI. Nineteen patients were transplanted in 1CR, two in 2CR, one in 1PR and two in relapse. Major toxicity was mucositis grade II according to the Bearman scale in all patients. The treatment-related mortality was 25%, mainly due to infection or GVHD after allogeneic transplantation. After a median follow-up of 45 months (range 2-93), nine patients (37.5%) remain alive in CR. Nine patients (37.5%) relapsed and eight (33.3%) of these subsequently died. After autologous transplantation, four of five patients (80%) relapsed and died. Late relapse was seen after allogeneic, as well as autologous transplantation, at 33 and 59 months, respectively. The Kaplan-Meier estimate of leukemia-free survival for all patients is 38% at 3 years (95% CI: 18-58%) and 35% at 5 years (95% CI: 15-55%). For allogeneic transplants in first CR (n = 15) the estimate of disease-free survival was 46% at 3 years (95% CI: 19-73%) and 34% at 5 years (95% CI: 17-51%). Patients aged below 30 years had a better estimated overall survival at 3 years (61% vs 11%, P < 0.001). The bcr-abl fusion transcript (p210 vs p190 vs p210/190) did not affect disease-free or overall survival. In our experience, an intensified conditioning regimen seems to improve the results of bone marrow transplantation in patients with Ph+ acute lymphoblastic leukemia. However, the high relapse rate warrants novel approaches to enhance anti-leukemic efficacy.

Specificity of reverse transcriptase polymerase chain reaction assays designed for the detection of circulating cancer cells is influenced by cytokines in vivo and in vitro

Several reverse transcriptase polymerase chain reaction (RT-PCR) assays have been described for the detection of circulating tumour cells in blood and bone marrow. Target mRNA sequences for this purpose are the cytokeratins (CK) 19 and 20, the carcinoembryonic antigen (CEA), and the prostate-specific antigen messages. In this study, we investigated biological factors influencing the specificity of the CK19 and CEA RT-PCR assays. Bone marrow, granulocyte colony-stimulating factor (G-CSF)-mobilized blood stem cells and peripheral blood samples obtained from healthy volunteers (n = 15; CEA n = 7), from patients with epithelial (n = 29) and haematological (n = 23) cancer and from patients with chronic inflammatory diseases (n = 16) were examined. Neither CEA nor cytokeratin 19 messages could be amplified from bone marrow samples from healthy subjects and from patients with haematological malignancies. In contrast, specimens from patients with inflammatory diseases scored positive up to 60%. To investigate the influence of inflammation on target mRNA expression, haemopoietic cells were cultured with and without cytokine stimulation in vitro. CK19 messages could be easily detected in cultured marrow cells without further stimulation, CEA messages only after gamma-interferon (gamma-INF) stimulation. In contrast, G-CSF-mobilized peripheral blood stem cells were positive for CK19 messages only after stem cell factor (SCF) or interleukin stimulation. We conclude that transcription of so-called tissue-specific genes is inductible in haemopoietic tissues under certain conditions. These factors have to be considered in future applications of RT-PCR for the detection of minimal residual disease.

[Psychological problems and treatment possibilities in intensive care medicine exemplified by bone marrow transplantation]

Bone Marrow resp. Peripheral Blood Stem Cell Transplantation (BMT/PBSCT) represents the only chance of cure for many patients with haematological diseases. Treatment and convalescence place significant stress not only on patients but on partners, siblings (who are frequently donors) and medical staff. Stressors are the high risk of mortality and chronic disabilities, acute treatment side-effects and multiple psychological and social demands. This requires support during longt-term psychosocial sequelae. We present problems and possible interventions in an acute and a rehabilitative medical setting, discussing recent findings in respect of donors' motivations, social support and quality of life. Psychosocial support in BMT should be given in a process perspective systematically combining and assessing in- and outpatient interventions.

Mobilizing peripheral blood stem cells with high-dose G-CSF alone is as effective as with Dexa-BEAM plus G-CSF in lymphoma patients

We compared retrospectively the efficacy of granulocyte colony stimulating factor (G-CSF) alone with chemotherapy plus G-CSF in mobilizing CD34-positive cells in patients with malignant lymphoma. 35 patients underwent peripheral blood stem cell (PBSC) collection following mobilization either with 24 microg/kg G-CSF for 4 consecutive days (n = 18) or Dexa-BEAM chemotherapy plus 5 microg/kg G-CSF (n = 17). High-dose G-CSF was well tolerated with only slight bone pain and/or myalgia. The Dexa-BEAM therapy required hospitalization with a median duration of 21 d. The median number of apheresis procedures in both groups was two (range two to four), resulting in a median of 5.3 and 5.1 x 10(6) CD34+ cells/kg. No patients in the G-CSF group, but one in the Dexa-BEAM group, failed to reach the target of collecting >2.0 x 10(6) CD34+ cells/kg. The number of CFU-GM (10.4 v 6.0 x 10(5)/kg) and of BFU-E (10.6 v 4.5 x 10(5)/kg; P = 0.04) was higher in the G-CSF group than in the Dexa-BEAM group. A subset analysis of CD34+ cells was performed in 16 patients showing a higher mean of Thy-1 (CD90w) coexpression in the G-CSF than in the Dexa-BEAM group (4.8 v 1.8%, P = 0.12). Additionally the percentage of CD34+/CD38- cells was higher in the G-CSF group (10.66% v 8.8%). However, these differences were not statistically significant. The median time to leucocyte and platelet engraftment after high-dose chemotherapy was slightly shorter in the G-CSF than in the Dexa-BEAM group (9 v 10 and 12 v 13.5 d, respectively). These results demonstrate that high-dose G-CSF is as effective as Dexa-BEAM plus G-CSF in mobilizing peripheral blood stem cells and produces prompt engraftment. The major advantages of G-CSF mobilization were the safe outpatient self-application and the fixed-day apheresis.

[Treatment of hemophagocytic lymphohistiocytosis, HLH, with bone marrow transplantation]

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease of infancy and young childhood. The clinical presentation includes recurrent unexplained fever with hepatosplenomegaly. Cytopenia, hypofibrinogenemia and/or hypertriglyceridemia and hemophagocytosis in bone marrow, spleen and lymphnode confirm the diagnosis. Hemophagocytosis may not be present at the beginning. In these cases, diagnosis is facilitated by a positive family history, a relapsing course of the disease, the frequent involvement of the central nervous system and positive findings on immunological work-up. Treatment by chemotherapy and immunosuppressants can achieve sustained remissions in most patients and reinduction of remission after relapse is possible. Most children however, eventually die from progressive disease. At present, allogeneic bone marrow transplantation is the only curative therapeutic option. Between August 1992 and May 1997 eleven consecutive patients with HLH received bone marrow from unrelated (n = 7) or matched sibling donors (n = 4). The conditioning regimen consisted of busulfan, VP-16 and cyclophosphamide. Patients engrafted after a median time of 16 days (13-43). Only one patient developed grade III acute GVHD, another patient, grade II acute GVHD. Although regimen-related toxicity was extensive, all patients have survived without signs of HLH after a median follow up of 20 months (8-63). One patient suffers from chronic GVHD, three patients reveal psychomotoric retardation and one patient has severe impairment with spastic tetraparesis, amaurosis and seizures. Our experience shows that HLH can be successfully treated by allogeneic BMT from unrelated donors.

Highly-efficient gene transfer with retroviral vectors into human T lymphocytes on fibronectin

Genetically modified lymphocytes have been successfully used for correction of ADA deficiency in children and in controlling graft-versus-host disease (GvHD) after allogeneic bone marrow transplantation. Low transduction efficiencies are, however, limiting for gene therapeutic strategies based on lymphocytes. In this study we compared protocols for highly efficient gene transfer into human T cells using retroviral vector-containing supernatant. We showed that infection of both human primary T cells and CD4+ Jurkat cells is most efficient on the matrix component fibronectin. Transduction was carried out with a retroviral vector encoding both the human intracytoplasmatically truncated low-affinity nerve growth factor receptor (deltaLNGFR) as a gene transfer marker and the Herpes simplex virus thymidine kinase for negative selection. Based on LNGFR expression genetically modified cells were enriched to near purity by magnetic cell sorting (MACS). Enriched cells could be shown to be highly sensitive to ganciclovir.

Busulfan, cyclophosphamide and etoposide as high-dose conditioning therapy in patients with malignant lymphoma and prior dose-limiting radiation therapy

Relapse after transplant for malignant lymphomas remains the main cause of treatment failure. Most conditioning regimens contain total body irradiation (TBI). We investigated the toxicity and efficacy of an intensified chemotherapy conditioning regimen without TBI in patients with relapsed or high-risk malignant lymphoma who had received prior radiation therapy and were therefore not eligible for TBI. Twenty patients with a median age of 38 (18-56) and relapsed or high-risk malignant non-Hodgkin's lymphoma (NHL, n = 16) or Hodgkin's disease (HD, n = 4) underwent high-dose chemotherapy consisting of busulfan (16 mg/kg), cyclophosphamide (120 mg/kg) and etoposide 30 mg/kg (n = 8) or 45 mg/kg (n = 12) followed by peripheral stem cell support (n = 14), autologous bone marrow (n = 3), allogeneic (n = 2) or syngeneic (n = 1) transplantation. All but two had chemosensitive disease before high-dose chemotherapy. The main toxicity -- according to the Bearman score -- was mucositis II in 18 (90%) patients; five patients (25%) suffered a grade I hepatic toxicity. GI toxicity I occurred in three (15%) and renal toxicity I in two patients (10%). Sixty percent of the patients developed transient dermatitis with erythema and three of them (15%) had skin desquamation; one patient experienced asymptomatic pancreatitis. Toxicity was slightly higher in patients treated with 45 mg/kg etoposide. One patient (5%) died of treatment-related venoocclusive disease. After a median follow-up of 50 months (24-84) the disease-free and overall survival were 50% and 55%. One of the nine relapsing patients developed secondary AML 18 months after transplant. High-dose busulfan, cyclophosphamide and etoposide is an effective regimen resulting in long-term disease-free survival in 50% of patients with relapsed malignant lymphoma and prior radiation therapy. The toxicity is moderate with a low treatment-related mortality (5%).

Successful mobilization of peripheral blood stem cells in heavily pretreated myeloma patients with G-CSF alone

We investigated the feasibility of mobilizing peripheral blood stem cells (PBSC) with G-CSF alone in 24 patients with multiple myeloma. The median age was 53 years (range 33-62). All patients had stage II/III disease and responded to standard first-line (n = 6) or salvage chemotherapy (n = 18). The median number of previous chemotherapy cycles was 7 (4-18) and the median number of prior melphalan-cycles was 6 (0-14). Nine (35%) patients had experienced prior radiation therapy. The patients received either 10 microg/kg G-CSF (n = 18) or 24 microg/kg G-CSF (n = 7, including one patient with previous 10 microg/kg G-CSF stimulation) daily s.c. for 5 or more consecutive days until completion of harvesting, starting apheresis on the fifth day. G-CSF treatment was well tolerated, with only slight bone pain in half of the patients (51%). After a median of three (range 1-7) apheresis procedures, medians of 3.8 (0.3-17) x 10(6) CD34+ cells/kg, 8.5 (4.5-24) x 10(8) MNC/kg, 2.9 (0.6-39.4) x 10(4) CFU-GM/kg, and 5.6 (0.9-49) x 10(4) BFU-E/kg were harvested. Three patients (12%) with extensive melphalan pretreatment failed the target collection of at least 2.0 x 10(6) CD34+ cell/kg. Pretreatment with six or more cycles of melphalan yielded a smaller number of CD34+ cells than pretreatment with fewer than six cycles (2.5 vs 5.3 x 10(6)/kg; p = 0.001). Nineteen patients underwent high-dose chemotherapy consisting of either total marrow irradiation (9 Gy)/busulfan (12 mg/kg) and cyclophosphamide (120 mg/kg) (n = 10), or busulfan (14 mg/kg)/cyclophosphamide (120 mg/kg) (n = 5), or tandem melphalan (200 mg/m2). The median time for granulocyte (> 1.0/nl) and platelet (> 50/nl) recovery was 10 and 14 days (ranges 7-12 and 8-40), respectively. G-CSF alone is a safe, alternative approach to mobilizing sufficient PBSC in patients with multiple myeloma and allows an exact prediction of harvest time. G-CSF-mobilized PBSCs ensure rapid engraftment after myeloablative therapy. Melphalan treatment should be avoided in patients who are candidates for high-dose chemotherapy.

Purging and haemopoietic progenitor cell selection by CD34+ cell separation

Tumour cell contamination of autologous peripheral blood stem cell samples (PBSC) and bone marrow (BM) is frequent. Enrichment of CD34+ stem cells is a promising approach to purging tumour cells from autografts without damaging progenitor cells. Breast cancer cells were seeded (10(-3)-10(-7)) into mononuclear cells from G-CSF-mobilised PBSC and BM harvests from patients without breast cancer. CD34+ cells were enriched from mixtures either by immunomagnetic separation (Isolex-50, and MiniMACS) or by biotin-streptavidin immunoaffinity columns (Ceprate-LC). CD34+ cell fractions were determined by FACS, cancer cells were detected immunocytochemically with an anti-pancytokeratin antibody. The CD34+ cells were enriched with a median purity of 92.2% (43.5-96.1) (n = 17) (Isolex-50), 96.5% (66.6-99.2) (n = 17) (MiniMACS) and 77.9% (31.4-93.6) (n = 15) (Ceprate-LC) from PBSC and BM harvests. The percentages of median recovery of CD34+ cells were 30.8% (18.6-71.8) (Isolex-50), 69.9% (39.1-100) (MiniMACS) and 42.9% (23.7-100) (Ceprate-LC). The median tumour cell reductions in log steps were 3.7 (2.9-4.3) (n = 13) (Isolex-50), 3.5 (2.6-4.3) (n = 13) (MiniMACS) and 1.5 (0.9-2.9) (n = 17) (Ceprate-LC). Results were compared statistically by univariate analysis. Purity was significantly (P < 0.05) better after MiniMACS selection. Recovery rates were significantly different between all devices tested. Tumour cell purging was superior after immunomagnetic separation (P < 0.001). Tumour cell purging is a main objective of CD34+ selection in the autologous setting. Our in vitro data clearly indicate that immunomagnetic separation is more efficient in the prevention of accidental reinfusion of contaminating tumour cells compared to immunoaffinity. However, it is not yet known if the same results can be obtained with fresh contaminating tumour cells.

Difference between expression of adhesion molecules on CD34+ cells from bone marrow and G-CSF-stimulated peripheral blood

Three-color immunofluorescence cytometry was used to quantify the expression of different adhesion molecules on CD34+ cells of steady-state bone marrow (BM) and peripheral blood stem cells (PBSC) after mobilizing with G-CSF (10 micrograms/kg/body weight) in nine cancer patients undergoing high-dose chemotherapy with subsequent autologous blood stem cell rescue. The expression rate of each adhesion molecule on CD34+ cells showed great inter-individual variations. High expression (> 50%) on CD34+ cells from PBSC and BM was found for CD58 (leukocyte function-associated antigen-3), CD31 (platelet-endothelial cell adhesion molecule-1), CD11a (leukocyte function-associated antigen-1) and CD49d (very late activation antigen-4); a moderate expression (20%-40%) was seen for CD49e (very late activation antigen-5), CD62L (leukocyte-endothelial cell adhesion molecule), CD54 (ICAM-1) and CD117 (c-kit). c-kit, CD58, CD62L and CD49d were less expressed on CD34+ cells of PBSC than of BM, the difference being statistically significant for CD49d (p < 0.05). CD49e and CD37 were expressed more in PBSC than BM without being statistically significant. The mean fluorescence intensity for all adhesion molecules on CD34+ cells did not differ significantly between PBSC and BM. The significantly lower expression of CD49d on G-CSF-mobilized PBSCs might suggest that downregulation of this molecule may be involved in the process of peripheral stem cell mobilization.

Long-term disease-free survival of patients with advanced mantle-cell lymphoma following high-dose chemotherapy

In advanced stage mantle cell lymphoma, conventional chemotherapy yields a complete remission rate below 40%, and the median survival rate is only about 3 years. Between 1991 and 1996 we treated nine such patients (six male; three female) with high-dose chemotherapy (six of these also with 12 Gy fractionated total body irradiation (TBI)) and peripheral stem cell support (n = 8) or allogeneic bone marrow transplantation (n = 1). The median age was 47 years (range, 28-61). At the time of high-dose chemotherapy, five patients were in first complete remission (CR), two in first partial remission (PR) and two in second remission (CR = 1; PR = 1). High-dose chemotherapy included TBI (12 Gy), etoposide and cyclophosphamide (patients 1-5), TBI and cyclophosphamide (patient 7), busulfan, etoposide and cyclophosphamide (patients 6 and 9), cyclophosphamide and busulfan (patient 8). The patterns of toxicity according to the Bearman score were usually mild (mucositis grade 2, n = 7; renal grade I, n = 2) with no therapy-related fatality. Only one patient developed hepatic toxicity grade III (veno-occlusive disease) but recovered completely. The median time to neutrophil engraftment was 10 days (range, 8-15). After high-dose chemotherapy all patients achieved complete remission. After a median follow-up of 22 months (range, 9.4-64) all patients remain in continuous complete remission. These encouraging results suggest that high-dose chemotherapy can be applied safely and leads to long-term disease-free survival in otherwise incurable disease.

Soluble interleukin-2 receptor serum levels after allogeneic bone marrow transplantations as a marker for GVHD

Acute GVHD (aGVHD) is one of the major problems after allogeneic BMT. The diagnosis of aGVHD is difficult to establish, relying mainly on clinical evaluations and symptoms of aGVHD, often resembling those of organ toxicity, infection or drug rash. In 21 patients after BMT several serum cytokine levels (soluble interleukin-2 receptor (sIL-2R), sTNF-R, SCF, IL-6, IL-8, G-SCF and ICAM-1) were determined in order to evaluate their value as an indicator for aGVHD. The maximum levels of sIL-2R (and none of the other evaluated cytokines) correlated significantly (r = 0.8, P = 0.008) with the severity of aGVHD. We also found a significant correlation between the day of engraftment (neutrophil count >0.5 x 10(9)/l) and the severity of aGVHD (r = 0.5, P = 0.03): engraftment was earlier in patients without aGVHD (median of day 11) than in those with aGVHD (median of day 18). No correlation between sIL-2R and fever or organ toxicity could be found. Our data suggest that the sIL-2R level might be an indicator for aGVHD, reflecting the severity of the disease. In patients with late engraftment the risk of aGVHD seems to be increased, therefore these patients especially should be monitored closely, possibly using sIL-2R levels.

High dose chemotherapy with busulfan, cyclophosphamide, and etoposide as conditioning regimen for allogeneic bone marrow transplantation for patients with acute myeloid leukemia in first complete remission

We explored the combination of busulfan/cyclophosphamide/etoposide as conditioning regimen prior to bone marrow transplantation in 31 patients with acute myeloid leukemia (AML) in first complete remission. The preparative regimen consisted of 16 mg/kg busulfan, 30-60 mg/kg VP-16, and 120 mg/kg cyclophosphamide. With a median follow-up of 30.5 months (range, 5-60 months), 25 patients are alive in continuous complete remission. Estimated disease-free survival at 5 years is 80.5%. Death was due to transplant-related toxicity (graft-versus-host disease and cytomegalovirus infection, graft-versus-host disease and pneumonia, sepsis and mucositis, respectively). None of the patients have relapsed. As demonstrated by the results of this analysis, the conditioning regimen busulfan/cyclophosphamide/etoposide is effective and well tolerated in patients with AML in first complete remission. Main nonhematological toxicities were mucositis and hepatotoxicity. The low mortality and relapse rate appears to justify allogeneic bone marrow transplantation for patients with AML in first complete remission who have an HLA-identical donor. Whether this regimen offers a substantial improvement in disease-free and overall survival over presently used regimens warrants further investigation.

Selective immunoaffinity-based enrichment of CD34+ cells transduced with retroviral vectors containing an intracytoplasmatically truncated version of the human low-affinity nerve growth factor receptor (deltaLNGFR) gene

Human hematopoietic stem cells remain one of the most promising target cells for gene therapeutic approaches to treat malignant and nonmalignant diseases. To rapidly characterize transduced cells and to isolate these from residual nontransduced, but biologically equivalent, cells, we have used a Moloney murine leukemia virus (Mo-MuLV)-based retroviral vector containing the intracytoplasmatically truncated human low-affinity nerve growth factor receptor (deltaLNGFR) cDNA as a marker gene. Supernatant transduction of CD34+ cells (mean purity 97%) in fibronectin-coated tissue culture flasks resulted in 5.5-45% (mean 26%) transduced cells expressing deltaLNGFR (LNGFR+ cells). After transduction, more than 65% of the transduced cells remained CD34+. Compared with control (mock- and nontransduced) CD34+ cells, transduction did not decrease the cloning efficiency of CD34+ cells. Immunomagnetic selection of the transduced cells with a monoclonal anti-LNGFR antibody resulted in >90% LNGFR+ cells. Further phenotypic characterization of these highly enriched LNGFR+ cells indicated that the majority co-expressed the CD34 and CD38 antigens. These results show that transduced cells expressing an ectopic cell-surface protein can be rapidly and conveniently quantitated and characterized by fluorescence-activated cell sorting (FACS) analysis and fast and efficiently enriched by immunoadhesion using magnetic beads. The use of cell-surface reporters should facilitate optimization of methods of gene transfer into more primitive hematopoietic progenitors.

Factors influencing haematological recovery after allogeneic bone marrow transplantation in leukaemia patients treated with methotrexate-containing GVHD prophylaxis. A single-centre experience

In the present single institution study of 66 leukaemia patients (28 AML, 23 ALL, 15 CML), the factors influencing haematological recovery after allogeneic bone marrow transplantation (alloBMT) were analysed retrospectively to identify the optimal conditions required for rapid haematological recovery after alloBMT. All patients received GVHD prophylaxis with cyclosporine A plus methotrexate. The mean number of days required to achieve a neutrophil count > or = 0.5 x 10(9)/l after alloBMT was 17 (range 9-27), 19 patients (28.8%) had rapid neutrophil recovery within 15 days after alloBMT. Haematological recovery was more rapid in the 38 patients without GVHD or with only grade I GVHD. Also, 50% and 40% of patients receiving 10 (n = 18) or 5 (n = 20) micrograms/kg G-CSF per day, respectively, had rapid neutrophil recovery within 15 days after alloBMT, as against only 7.1% of patients not receiving G-CSF after the transplant (n = 28); P < 0.001. The neutrophil recovery was similar in patients receiving either fresh or cryopreserved allografts and either a TBI-containing or a busulfan-containing conditioning regimen. A significant correlation was found between the neutrophil recovery and either the MNCs or CFU-GM contents of the allografts. The mean number of days required for neutrophil recovery was only 16 (range 9-24) in patients receiving allografts containing > 1 x 10(5) CFU-GM/kg (n = 28), as against 19 (range 13-27) in patients receiving allografts containing < or = 1 x 10(5) CFU-GM/kg (n = 35). Three patients receiving allografts containing < 0.5 x 10(5) CFU-GM/kg had primary neutrophil engraftment failure. The mean number of days required to achieve a platelet count > or = 20 x 10(9)/l was 21 (range 11-50), and 30 patients (46.9%) had platelet recovery within 20 days after alloBMT. The platelet recovery after alloBMT was not affected by the type of leukaemia, conditioning regimen, or G-CSF administration. The mean number of days required for platelet recovery after alloBMT was 20 in patients receiving allografts containing > 1.0 x 10(5) BFU-E/kg (n = 35), as against 23 days in patients receiving allografts containing < or = 1.0 x 10(5) BFU-E/kg (n = 24). Seven patients receiving allografts containing < 0.5 x 10(5) BFU-E/kg had primary platelet engraftment failure. The present study has identified the high number of progenitor cells in the allografts infused and the daily administration of G-CSF posttransplant as the optimal combination for rapid neutrophil recovery after alloBMT. More significantly, the number of BFU-E in allografts was the most significant determining factor in platelet recovery after alloBMT. The development of GVHD of grade II or more during the first weeks after alloBMT was associated with slower haematological recovery, a longer period of fever during neutropenia and longer hospitalization.