Long-term follow-up of allogeneic stem cell transplantation in patients with severe aplastic anemia after conditioning with cyclophosphamide plus antithymocyte globulin

We investigated the efficacy of an antithymocyte globulin/cyclophosphamide preparative regimen prior to allogeneic stem cell transplantation from HLA-identical siblings in patients with severe aplastic anemia. Since 1990, 21 patients, 6 males and 15 females, with a median age of 25 years (range: 7-43) have been enrolled in the protocol consisting of 200 mg/kg cyclophosphamide and 90-120 mg/kg antithymocyte globulin (ATG, rabbit, Fresenius, Bad Homburg, Germany). For further graft-versus-host disease (GVHD) prophylaxis all patients received cyclosporin A and a short course of methotrexate (MTX). Only one patient had a primary graft failure (5%). All other patients engrafted with a leukocyte count >1.0 x 10(9)/l and a platelet count >20 x 10(9)/l after a median of 19 (range: 11-28) and 26 days (range: 13-67), respectively. No late graft failure or relapse was observed. Two patients experienced mild acute GVHD grade I (10%), and one patient developed grade II GVHD (5%). No severe grade III/IV GVHD was observed; 17% of the patients developed limited chronic GVHD. The treatment-related mortality was 14% and mainly due to fungal infection. After a median follow-up of 70 months (range: 2-139), the estimated overall and event-free survival at 10 years for all patients is 86% (95% confidence interval: 70-100%). We conclude that ATG plus cyclophosphamide is an effective conditioning regimen in patients with aplastic anemia undergoing stem cell transplantation with a low treatment-related mortality, resulting in an excellent outcome.

TNFalpha, interleukin-10 and interleukin-18 expression in cells of the bronchoalveolar lavage in patients with pulmonary complications following bone marrow or peripheral stem cell transplantation: a preliminary study

Pulmonary complications pose a major clinical problem after bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT). The underlying pathophysiological mechanisms are under investigation. Twenty patients with infectious or non-infectious pulmonary complications after BMT or PBSCT underwent bronchoalveolar lavage (BAL) and tumor necrosis factor-alpha (TNFalpha), interleukin-10 (IL-10) and interleukin-18 (IL-18) mRNA expression was determined in BAL cells in comparison to 11 healthy volunteers. Patients were divided into two groups (infectious pneumonia, n = 14 or idiopathic pneumonia syndrome (IPS)/bronchiolitis obliterans (BO), n = 6). TNFalpha expression was significantly increased in both patient groups compared to the control (0.40 +/- 0.07 and 0.39 +/- 0.09 vs 0.15 +/- 0.05; P < 0.05; semiquantitative PCR analysis; mean +/- s.e.m.). IL-10 expression was significantly elevated the group of patients with infectious pneumonia in comparison to normal controls (0.15 +/- 0.06 vs 0.01 +/- 0.01; P < 0.05) but not in patients with IPS/BO (0.05 +/- 0.04; P > 0.05). However, IL-10 was not expressed in BAL cells of all patients and control individuals. IL-18 expression was significantly decreased in the both patient groups (1.47 +/- 0.24 and 1.79 +/- 0.63) in comparison to the control group (4.29 +/- 0.77; P < 0.05). Survival analysis showed a significant association between elevation of TNFalpha and poor prognosis (P < 0.05). These results highlight the immunoregulatory disturbances in the lungs after BMT/PBSCT.

Persisting multilineage transgene expression in the clonal progeny of a hematopoietic stem cell

Many applications of hematopoietic gene therapy require selection for clones with active transgene expression. However, it was unclear whether the clonal progeny of a retrovirally transduced hematopoietic stem cell would be capable of maintaining transgene expression through serial repopulation and multilineage differentiation. Such investigations require simultaneous analyses of clonality, multilineage activity and transgene copy numbers. Using a mouse model, the present study demonstrates that a single hematopoietic stem cell expressing a marker gene from one or two insertions of a simple retroviral vector actively maintains multilineage transgene expression in the vast majority (80-99%) of bone marrow and peripheral blood cells. Gene expression persisted through serial transplantations for at least 97 weeks post gene transfer and was observed in the lymphoid (B, T and NK cells), myeloid (CD11b(+), Gr-1(+)), erythroid (Ter119(+), mature red blood cells) and megakaryocytic (as indicated by platelets) progeny. Therefore, a single immunoselection for hematopoietic stem cells expressing the transgene in vivo was sufficient to establish a completely chimeric hematopoiesis. These observations imply that the retroviral vectors used in this study contain cis-elements that mediate expression through massive clonal expansion and multilineage differentiation, provided the insertion occurred in genetic loci permissive for expression in hematopoietic stem cells.

[Unrelated donor stem cell transplantation in children: low toxicity using a GvHD-prophylaxis regimen with CSA, MTX, metronidazole,iv-immunoglobulin and ATG]

BACKGROUND

Unrelated donor (UD) hematopoietic stem cell transplantation (HSCT) is accepted as a therapy for leukaemic diseases and varying inborn diseases if a suitable related donor cannot be found. The goal of immunosuppressive therapy with UD-HSCT is an effective prevention of graft-versus-host-disease (GvHD) on one hand. On the other hand an optimal balance with immunocompetence of the transplanted bone marrow is desirable in order to prevent graft failure, infection and, in the case of leukaemic diseases, potentially control the underlying disease.

PATIENTS AND METHODS

Between 1992 and 2000 49 patients aged 11 months to 16.7 years received an UD-HSCT in Hamburg. Underlying diseases were leukaemia or MDS in 35, of these ALL in 21, hemophagocytic lymphohistiocytosis (HLH) in 9, immunodeficiency or inborn error of metabolism in 5 patients. GvHD-prophylaxis consisted of a combination of Cyclosporin A (CSA), methotrexate (MTX), metronidazole, IgM-enriched iv-immunoglobulin (ivIg) (Pentaglobin(R)) or ivIgG and anti-thymocyte-globulin (ATG). Within the same time span 10 patients with ALL received a matched related donor HSCT (MRD-HSCT). GvHD-prophylaxis in these patients was done without ATG in 8 of 10 cases. UD-HSCT were analyzed for survival, relapse and toxicity. Probability of survival of the patients with ALL after UD-HSCT was compared with results of MRD-HSCT in children with ALL.

RESULTS

The Kaplan-Meier estimates of three year overall-survival (OS) were 74 % for all patients. Probability of disease-free survival (DFS) at three years was 62 % for leukaemia/MDS-patients and 100 % for the HLH-patients. Acute GvHD (aGvHD) grades II or III occurred in 51 % of patients. Chronic GvHD (cGvHD) occurred in 22 % of patients. There were 5 cases of treatment-related mortality (TRM). Probability of DFS for patients with ALL at three years was 65 % after UD-HSCT and 30 % in the patients after MRD-HSCT.

CONCLUSIONS

UD-HSCT in children is an effective and safe therapy. A GvHD-prophylaxis regimen combining the standard immunosuppressive agents CSA and MTX with ivIg, metronidazole and serotherapy using ATG may result in a low incidence of severe GvHD-complications and low TRM rate without increase in relapse rates.

Stem cell mobilisation with 16 microg/kg vs 10 microg/kg of G-CSF for allogeneic transplantation in healthy donors

We compared two doses of recombinant human granulocyte-stimulating factor (G-CSF) for stem cell mobilisation in 90 healthy donors for allogeneic stem cell transplantation in a retrospective analysis. Group I (n = 46) received 10 microg/kg G-CSF (filgrastim) given as 5 microg/kg twice daily, and group II (n = 44) received 16 microg/kg, given as 8 microg/kg twice daily with a 12-h interval. The groups were well-balanced for age and body-weight. G-CSF application was performed on an out-patient basis, and leukapheresis was started in all donors on day 5. The most frequent side-effects of G-CSF were grade I/II, bone pain, headache and fatigue in both groups, whereas grade III of bone pain, headache and fatigue occurred in the 2 x 8 microg/kg group only. One serious non-fatal event with non-traumatic spleen rupture occurred in the 2 x 5 microg/kg group. The CD34(+)cell count in the first apheresis of all donors was 5.1 x 10(6)/kg donor weight (range, 1.5-19.3). The CD34(+) cell harvest was higher in the 2 x 8 microg/kg group than in the 2 x 5 microg/kg group (7.1 x 10(6)/kg vs 4.9 x 10(6)/kg; P = 0.09). The target of collecting >5.0 x 10(6) CD34(+) cells/kg donor weight with one apheresis procedure was achieved in 45% of group I and in 61% of group II, respectively. Administering G-CSF at a dosage of 8 microg/kg twice daily leads to a higher CD34(+) cell yield than a dosage of 2 x 5 microg/kg, but is associated with increased toxicity and higher cost.

Correlation of time to platelet engraftment with amount of transplanted CD34+CD41+ cells after allogeneic bone marrow transplantation

A major problem after autologous or allogeneic stem cell transplantation is prolonged thrombocytopenia. There are several studies published about correlations of the composition of the graft and time to platelet engraftment for autologous transplantation but only a few studies for allogeneic transplantation. In our study, we wanted to find out whether the correlation between the time to platelet engraftment and amount of transplanted CD34(+)CD41(+) cells described previously after autologous peripheral blood stem cell transplantation could be reproduced in the allogeneic bone marrow transplantation setting. We found correlations not only for the number of transplanted CD34(+) cells with the time to leukocyte engraftment (r = -0.32, p = 0.045) but also for the number of transplanted CD34(+)CD41(+) cells and time to platelet engraftment (r = -0.34, p = 0.038), which were both statistically significant. A significant correlation between transplanted CD34(+) cells versus platelet engraftment and transplanted CD34(+)CD41(+) cells versus leukocyte engraftment was not found. The finding that the amount of committed megakaryocyte progenitor cells in the graft is an important predictive factor for platelet engraftment after allogeneic bone marrow transplantation might be the base for future studies of ex vivo expansion of clonable megakaryocyte precursors.

In vivo T cell depletion with pretransplant anti-thymocyte globulin reduces graft-versus-host disease without increasing relapse in good risk myeloid leukemia patients after stem cell transplantation from matched related donors

One-hundred and two patients with good risk myeloid leukemia (CML first chronic phase or AML first CR) were transplanted from HLA-related donors after conditioning with (n = 45) or without anti-thymocyte globulin (ATG) (n = 57). One graft failure was observed in the non-ATG and none in the ATG group. The median time to leukocyte engraftment (> 1 x 10(9)/l) was 16 (range 12-33) in the ATG group and 17 days (range 11-29) in the non-ATG group (NS) and for platelet engraftment (> 20 x 10(9)/l) 24 and 19 days (P = 0.002), respectively. Acute GVHD grade II-IV was observed in 47% of the non-ATG and in 20% of the ATG group (P = 0.004). Grade III/IV GVHD occurred in 7% of the ATG and in 32% of the non-ATG group (P = 0.002). Chronic GVHD was seen in 36% and 67% (P = 0.005), respectively. After a median follow-up of 48 months (range 2-128), the 5-year estimated OS is 66% (95% KI: 51-81%) for the ATG group and 59% (95% KI: 46-72%) for the non-ATG group (NS). The 5-year estimated DFS is 64% (95% KI: 50-78%) for ATG and 55% (95% KI: 43-67%) for the non-ATG regimen (NS). The 5-year probability of relapse was 5% in the ATG and 15% in the non-ATG group (NS). ATG as part of the conditioning regimen leads to a significant reduction in GVHD without increase of relapse in patients with myeloid leukemia after stem cell transplantation from HLA-related donors.

Interference of cytokeratin-20 and mammaglobin-reverse-transcriptase polymerase chain assays designed for the detection of disseminated cancer cells

Several reverse-transcriptase polymerase chain reaction (rtPCR) assays have been designed for the detection of disseminated cancer cells. The specificity of these discussed molecular approaches is controversial. Biological interference of the cytokeratin-20 and mammaglobin rtPCR assays has been investigated. Cell lines of different lineages and bone marrow and peripheral stem cells from patients without epithelial cancer have been examined for the transcription of the cytokeratin-20 (CK20) and mammaglobin messages prior to and after stimulation with different cytokines in a total of 370 liquid cultures. Amplification of both messages from clinical samples prior to stimulation does not support the high specificity for the detection of disseminated epithelial cancer cells as reported. Cytokeratin-20 was amplified from the chronic myeloic leukemia (CML)-derived line K562. Transcription was not influenced by cytokines, either in cell-line experiments or in clinical samples. The thesis of a low-level background transcription in granulocytes is supported. Mammaglobin was induced in cell lines significantly by GM-CSF and in clinical samples additionally by several more cytokines. These results indicate that under certain conditions involving cytokine production, the use of mammaglobin rtPCR for the detection of epithelial cancer cells could be limited. In conclusion, the mechanism of interference of both rtPCR assays are completely different and further research is necessary before the cytokeratin-20 or mammaglobin rtPCR could become standard methods for the detection of disseminated epithelial cancer cells. These factors leading to so-called false-positive results have to be considered in future applications of rtPCR for the detection of minimal residual disease.

The role of biomedical and psychosocial factors for the prediction of pain and distress in patients undergoing high-dose therapy and BMT/PBSCT

Recent research has shown that cancer patients undergoing bone marrow transplantation (BMT) experience moderate to severe mouth pain due to treatment-related mucositis in spite of morphine therapy. Treatment-related emotional distress in BMT patients is also described widely. This study examined several biomedical, psychological and social variables as possible predictors for the intensity of treatment-related mouth pain and anxious mood in 63 cancer patients undergoing BMT or stem cell transplantation (SCT) within a prospective longitudinal design. Biomedical predictors included biomedical risk, mucositis, the mode of transplantation, total body irradiation, age and gender. Psychological predictors were depression (BDI), BMT-related distress, chronic stress and resources in everyday life (KISS), pain-related coping behaviour (KPI-17) and social support (ISSS). Among the social variables we evaluated education, being married and the living situation. Criteria variables were the intensity of mouth pain and anxious mood which were assessed daily by numeric self-rating scales for 24 days after transplantation. Results of stepwise multiple regressions indicated that psychological and social variables were important predictors of mouth pain, besides biomedical variables. Whereas the biomedical variables revealed the most predictive power during the second week after BMT, psychological predictors were more important during the early and late phases of the treatment. Daily anxious mood was best predicted by psychological and social variables. Among the biomedical variables mucositis was most strongly related to mouth pain besides mode of transplantation, risk, TBI and age. Among the psychological variables BMT-related distress was the most important predictor, with resources in private life or at work and pain-related coping modes as further significant predictors. These results imply that relevant predictors should be assessed as high risk factors for an increased vulnerability for treatment-related side-effects before treatment starts indicating an additional offer of psychological treatment in high risk patients.

Busulfan, cyclophosphamide, and etoposide as high-dose conditioning regimen in patients with malignant lymphoma

We investigated the efficacy and toxicity of the combination of busulfan, cyclophosphamide, and etoposide (Bu/Cy/VP-16) as a preparative regimen prior to autologous hematopoietic stem cell transplantation (ASCT) in patients with Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL). Fifty-three patients with recurrent ( n=30), refractory ( n=20), or high-risk ( n=3) lymphoma were enrolled. The 10 patients with HD and 43 with NHL (median age: 46 years, range: 18-64) received busulfan (16 mg/kg), cyclophosphamide (120 mg/kg), and etoposide (30 or 45 mg/kg) followed by ASCT. A total of 50 patients (94%) were consolidated in complete ( n=25) or partial ( n=25) remission, whereas 3 patients had chemoresistant disease before Bu/Cy/VP-16. Thirty-five patients (66%) had received prior radiotherapy (RT) excluding total body irradiation (TBI) as part of the conditioning regimen. The main nonhematological toxicities (grade II-IV according to the Bearman score) in 52 evaluable patients were mucositis (79%) and hepatic toxicity (15%). Severe veno-occlusive disease (VOD) occurred in three patients (5.8%) including one treatment-related death caused by VOD. Overall, treatment-related mortality was 3.8%. After a median follow-up for surviving patients of 21 months (range: 6-118), 20 patients (38%) are in continuous complete remission, 8 patients (15%) are alive in relapse, and 25 patients (47%) died. Probabilities of relapse, event-free survival, and overall survival at 3 years were 63% [95% confidence interval (CI): 48-79%], 31% (95% CI: 17-46%), and 43% (95% CI: 27-59%), respectively. In conclusion, Bu/Cy/VP-16 is an effective and well-tolerated conditioning regimen in patients with HD and NHL. Both toxicity and outcome were not significantly different in patients treated with 30 mg/kg and 45 mg/kg etoposide, respectively. The observed long-term results are even comparable to those published for other established high-dose protocols, including TBI-based regimens. However, further investigations are necessary to evaluate the value of Bu/Cy/VP-16 as a high-dose protocol for malignant lymphoma, especially in patients who have already received extensive RT.

The effect of IgM-enriched human Ig and rabbit antithymocyte globulin on the stimulation of mononuclear cells

Whether IgM-enriched intravenous Ig (pentaglobin) is a useful adjunct treatment for graft versus host disease (GvHD) prophylaxis in allogeneic stem-cell transplantation is unclear. Clinical data with the use of a five-agent GvHD prevention regimen, including pentaglobin and antithymocyte globulin (ATG), are encouraging. In vitro both have been reported to modulate alloreactive T cells. We compared their inhibitory effect on the phytohemagglutinin-induced lymphocyte proliferation. ATG blocked the proliferation of lymphocytes at lower doses and much stronger than pentaglobin. The combination of both was not different from ATG alone. In pentaglobin, glucose used as stabiliser, caused the effect. Starting at a concentration of 40 mg/dL glucose, glucose alone showed a dose-dependent inhibition of phytohemaglutinin (PHA)-induced proliferation. For the in vivo application of pentaglobin, the results suggest that pentaglobin does not inhibit the proliferation of T cells.

Second German consensus on immunogenetic donor search for allotransplantation of hematopoietic stem cells

The present paper summarizes the results of the second German consensus meeting on immunogenetic donor search for allotransplantation of hematopoietic stem cells held in Essen in November 1999 under the auspices of the German Society for Immunogenetics (DGI) and the German Working Party for Blood and Marrow Transplantation (DAG-KBT). Immunogeneticists and transplant physicians from all over the country agreed to update the national standards for: (1) search strategy including the role of unrelated and extended family donor search after unsuccessful core family donor search, (2) histocompatibility loci to be typed, (3) histocompatibility typing techniques to be used (HLA serology vs DNA-based HLA typing, cellular tests, serum cross-match), and (4) acceptable HLA mismatches in the context of a defined underlying disease, donor type, and conditioning regimen.

Practices of infectious disease prevention and management during hematopoietic stem cell transplantation: a survey from the European group for blood and marrow transplantation

Protocols for the prevention of infections after allogeneic or autologous hemopoietic stem cell transplantations are usual. A questionnaire was sent out to the members of the European Group for Bone and Marrow Transplantation (EBMT) in the spring of 1999. A total of 308 questionnaires from 180 centers were returned. Both allogeneic and autologous transplantation was reported from 128 centers, and allogeneic or autologous transplantation alone from four and 48 centers, respectively. Hemopoietic stem cell transplantation is still a domain of university hospitals. Intensive measures of isolation are usual. Allotransplantation is commonly performed in single rooms with HEPA-filtered air on special wards. However, even in the autologous setting, extensive measures of isolation are commonly used. This observation could be explained by historical developments and by the fact that nearly all centers for allogeneic transplantation perform both allogeneic and autologous transplantations, and thus similar measures are used in both settings. Other measures are usual but heterogeneous due to lack of clinical trials in this field. Drug prophylaxis during transplantation is mostly carried out with quinolones, TMP/SMZ, fluconazole, acyclovir, and pentamidine. Differences in drug prophylaxis after engraftment and in the use of different venous accesses do reflect the requirements after engraftment and discharge of patients from the transplant unit. The intensity of measures in autologous stem cell reinfusion does not reflect the development during the last decade. For cost effectiveness and convenience, it is necessary to abolish senseless measures. It is necessary to investigate anti-infectious strategies separately for allogeneic transplantation and other modalities of anti-cancer treatment in future.

T lymphocytes as targets of gene transfer with Moloney-type retroviral vectors

Peripheral T lymphocytes are a target of choice for many gene therapeutic strategies. Retrovirus-mediated transduction allows genomic integration and long-term expression of transgenes in target cells. Over many years, low transduction efficiency into primary T lymphocytes has limited clinical application of existing protocols. Recently, gene transfer rates > 50% have been achieved facilitating clinical studies. More attention is thus being focused on the ability of gene-modified cells to carry out innate as well as conferred functions in vivo and the influence of culture conditions, retroviral vector and host response thereon.

Disseminated breast cancer cells prior to and after high-dose therapy

Women with breast cancer in a distinct stage of disease can benefit from high-dose therapy (HDT) with autologous stem cell support; however, a significant number of these patients relapse despite this intensive treatment. This study investigates the persistence of malignancy on the single-cell level. A total of 194 data sets consisting of bone marrow and blood samples obtained prior to and after HDT and of aliquots of apheresis products were searched with immunocytochemistry and reverse transcriptase polymerase chain reaction (RT-PCR) for disseminated cancer cells. Presence of cancer cells in the marrow is frequent prior to and after HDT, but HDT reduces the amount of malignant cells in marrow significantly. In contrast, there was no effect on the number of circulating cancer cells. Reinfusion of contaminated apheresis products was surprisingly associated with a low number of malignant cells in bone marrow after HDT and vice versa. The impact of disseminated tumor cells in bone marrow, apheresis, and peripheral blood on disease-free survival after HDT could be investigated in a total of 165 samples. Surprisingly, neither the presence of tumor cells in marrow or blood nor in apheresis was associated with a bad prognosis in Kaplan-Meyer survival analysis. These results suggest that apheresis products and bone marrow should be regarded as different biological compartments for epithelial cancer cells. It can be concluded that complete elimination of disseminated cancer cells by HDT is not always possible. The theory of reinduction of metastatic breast cancer by accidentally reinfused contaminants is not supported by this study so far. However, further research is necessary to identify distinct cell populations with the potentially capacity to metastasize.

A fludarabine-based dose-reduced conditioning regimen followed by allogeneic stem cell transplantation from related or unrelated donors in patients with myelodysplastic syndrome

We investigated the feasibility and efficacy of a fludarabine-based dose-reduced conditioning regimen followed by stem cell transplantation from related (n = 5) or unrelated HLA-matched donors (n = 7) in 12 patients with high risk MDS, who were not eligible for a standard myeloablative conditioning regimen. The conditioning regimen consisted of fludarabine 30 mg/m(2) daily for 6 days, busulfan 4 mg/kg daily for 2 days and anti-thymocyte globulin (ATG, rabbit) 10 mg/kg daily for 4 days in 11 patients, while one patient received fludarabine, ATG, cyclophosphamide and thiotepa. Graft-versus-host disease prophylaxis consisted of cyclosporine and a short course of methotrexate. The median age of the patients was 53 years (range 37-59). The median percentage of blasts in bone marrow aspirate at transplantation was 15% (range <5% to 35%). Diagnosis at transplant was RA (n = 1), RAEB (n = 5), RAEB-T (n = 5) and sAML (n = 1). A complex karyotype including monosomy 7 was noted in five patients. The reasons for using a dose-reduced conditioning regimen were prior autologous/syngeneic BMT (n = 4), active fungal infection (n = 2) or age/reduced performance status (n = 6). Engraftment was observed in all patients with complete donor chimerism. The incidence of acute GVHD (grade II-IV) was 33%. Eight patients died during follow-up due to relapse (n = 4), liver toxicity (n = 2), aspergillus (n = 1) or aGVHD grade IV (n = 1). After a median follow-up of 19 months, the 2-year estimated disease-free survival is 12% (95% CI: 2-23%) and the overall survival is 26% (95% CI: 4-52%). Fludarabine dose-reduced conditioning prior to allogeneic stem cell transplantation in high risk MDS patients, who were not eligible for standard transplantation, resulted in stable engraftment with complete chimerism, but the toxicity and relapse rate were considerable.

Salvage chemotherapy with mitoxantrone, fludarabine, cytarabine, and cisplatin (MIFAP) in relapsing and refractory lymphoma

PURPOSE

The aim of the study was to evaluate the feasibility and efficacy of the combination of mitoxantrone, fludarabine, cytarabine, and cisplatin (MIFAP) in patients with prognostically unfavorable recurrent and refractory Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL).

METHODS

Forty-six patients (median age 43 years, range 18-63) with relapsed (n = 15) or refractory (n = 31) malignant lymphoma were enrolled (HD, n = 13; low-grade/transformed NHL, n = 4; high-grade NHL, n = 29). A total of 39 patients (85%) showed multiply relapsed diseases with a duration of prior remission of < 12 months (n = 8) or had lymphoma being resistant to prior chemotherapy (n = 31). The MIFAP therapy consisted of fludarabine (15 mg/m2, q. 12 h, day 1-4), cytarabine (50 mg/m2 by continuous infusion (CI) over 22 h, day 1-4), cisplatin (25 or 30 mg/m2 by CI over 24 h, day 1-4), and mitoxantrone (4 mg/m2, day 2-5).

RESULTS

Thirteen patients (28%) achieved complete remission (CR) and 15 patients (33%) partial remission (PR), for an overall response (OR) rate of 61%. Twenty-two patients responding to MIFAP (10 CR, 12 PR) have been consolidated by high-dose therapy (HDT) with hematopoietic stem cell transplantation (SCT). After a median follow-up of 12 months, 16 patients are in continuous CR (CCR) (n = 14) or CCRu (unconfirmed) (n = 2). The median duration of event-free survival (EFS) and overall survival (OS) were 6.5 and 19.3 months, respectively. Probabilities of EFS and OS after 3 years were 19% and 40%. Responders consolidated by subsequent HDT showed rates for 3-year EFS and OS of 40% and 66%, respectively. Unfavorable prognostic factors for EFS by univariate analysis were refractory lymphoma and the presence of B-symptoms. Significant prognostic factors for OS were NHL, refractory lymphoma, B-symptoms, and bone marrow involvement. The major toxicities were leukocytopenia and thrombocytopenia of the World Health Organization (WHO) grade IV in nearly all courses (median duration 10 and 11 days). In contrast, non-hematological side effects were moderate, predominantly of WHO grades I and II. Treatment-related mortality with MIFAP was 4% (two patients with septicemia by Aspergillus fumigatus).

CONCLUSIONS

MIFAP is an effective salvage protocol for patients with poor-risk recurrent or refractory HD and NHL. The observed toxicity seems to be acceptable considering the unfavorable prognosis and intensive pretreatment. The results in patients responding to MIFAP and afterwards undergoing HDT with autologous stem cell support are even comparable to those published in patients with prognostically more favorable diseases.

Jurkat cell-reactive anti-thymocyte globulin assessed ex vivo by flow cytometry persists three weeks in circulation

Rabbit anti-thymocyte globulin (ATG-Fresenius) is a polyclonal anti-serum raised against the lymphoblastic T cell line Jurkat. It is used for in vivo depletion of host and donor T cells for allogeneic stem cell transplantation. After administration of 90 mg/kg prior to transplant, rabbit immunoglobulin G (IgG) remains present for 4-5 weeks, but it is unknown how long T cell-reactive antibodies persist. Therefore, we measured anti-Jurkat antibodies by flow cytometry. The detection limit for Jurkat-reactive antibodies was 0.1 microg/ml rabbit IgG; half-maximal labeling of Jurkat cells required 183 microg/ml rabbit ATG. The mean half-life of Jurkat-reactive antibodies in 7 patients was 4 days. Detectable levels persisted up to 3 weeks with antibody levels equivalent to 0.2-4.1 microg/ml rabbit ATG. Jurkat-reactive antibodies were eliminated two-fold faster than rabbit IgG, as assessed by enzyme-linked immunosorbent assay (ELISA). The results suggest that in patients pretreated with ATG before transplantation, residual anti T-cell antibodies may effectively modulate recovery of T cells generated after transplantation, thereby lowering the incidence of severe GVHD.

Patient cytomegalovirus seropositivity with or without reactivation is the most important prognostic factor for survival and treatment-related mortality in stem cell transplantation from unrelated donors using pretransplant in vivo T-cell depletion with anti-thymocyte globulin

We evaluated the cytomegalovirus (CMV) serostatus as a risk factor for survival and treatment-related mortality (TRM) in 125 patients allografted from an unrelated donor between 1994 and 1999. All patients received pretransplant in vivo T-cell depletion using rabbit anti-thymocyte globulin (ATG). Only one patient had primary graft failure and severe grade III/IV graft-versus-host disease occurred in 14% of the patients. The overall survival (OS) at 3 years was 70% for CMV-negative patients (n = 76) and 29% in the seropositive cohort (n = 49) (P > 0.001). In multivariate analyses, CMV seropositivity remained an independent negative prognostic factor for OS (RR: 2.1; CI: 1.2-3.8; P = 0.014), apart from age > 20 years (RR: 2.74; CI: 1.2-3.8; P = 0.004) and late leucocyte engraftment (RR: 2.4; CI: 1.2-4.9; P = 0.015). The TRM for all patients was 27%. Despite monitoring for CMV antigenaemia and preemptive therapy with ganciclovir when reactivation occurred, seropositive patients had a three times higher risk of fatal treatment-related complications than seronegative patients. In multivariate analyses, CMV seropositivity remained the strongest independent negative factor for TRM (RR: 5.3; CI: 1.9-14.6; P = 0.002), followed by age > 20 years (RR: 4.8; CI: 1.3-18.1; P = 0.02) and delayed leucocyte engraftment (RR: 3.6; CI: 1.2-11; P = 0.02). The TRM was identical in seropositive patients with (n = 27) or without (n = 22) CMV reactivation (44% versus 50%). We conclude that CMV seropositivity, despite preemptive ganciclovir therapy and even without reactivation, is a major negative prognostic factor for survival as well as for TRM in unrelated stem cell transplantation using pretransplant in vivo T-cell depletion with ATG.

Real-time quantitative Y chromosome-specific PCR (QYCS-PCR) for monitoring hematopoietic chimerism after sex-mismatched allogeneic stem cell transplantation

Y chromosome-specific sequences can be used to detect remaining male cells after sex-mismatched allogeneic blood stem cell transplantation (HSCT) involving a male patient and female donor, which represents approximately 25% of all cases. We developed a quantitative Y chromosome-specific PCR assay (QYCS-PCR) based on the DFFRY gene for the determination of hematopoietic donor chimerism. We analyzed blood and marrow samples from more than 40 patients at various time points after both standard and nonmyeloablative allogeneic HSCT. We found that real-time PCR combines extreme sensitivity, with a detection level of less than 1 male in 100,000 female cells (<0.001%), with very good reproducibility, especially in the important range of minor host chimerism. QYCS-PCR results were in close agreement with data from other techniques as bcr/abl-PCR and/or fluorescent in situ hybridization (FISH) analysis. In two relapsed patients, increasing numbers of Y-positive hematopoietic cells indicated recurrence of malignant disease prior to clinical confirmation. In conclusion, quantitative Y chromosome-specific PCR is a promising approach for monitoring the extent of chimerism in blood and other tissues after sex-mismatched hematopoietic stem cell transplantation (HSCT) or organ transplantation.

Anti-thymocyte-globulin as part of the preparative regimen prevents graft failure and severe graft versus host disease (GvHD) in allogeneic stem cell transplantation from unrelated donors

To reduce the incidence of GvHD and the rate of graft failure in unrelated stem cell transplantation, we incorporate anti-thymocyte globulin in the preparative regimen in 98 patients with hematological or inherited storage disease. The median age was 32 years (range: 1-56) and 84 patients underwent transplantation from HLA-A,-B and DR identical donor, while in 14 patients the donor were mismatched either in HLA- A, -B or -DR locus. Only one patient with chronic myelocytic leukemia (CML) and blast crisis had a primary graft failure (1%). Grade II-IV acute GvHD occurred in 37 patients (37%), grade III/IV GvHD developed in 15 patients (15%). Chronic GvHD was observed in 29%, and only 12 patients had extensive GvHD (17%). After a median follow-up of 34 months (range, 9-90), the estimated overall survival at 3 years for all patients is 58% (CI 95%: 48%-68%), and the estimated disease-free survival at 3 years is 49% (CI 95%: 38%-60%). For patients with CML transplanted in first chronic phase or accelerated phase (n=40), the estimated overall survival at 3 years is 70% (CI 95%: 56%-84%), and the estimated disease-free survival at 3 years is 58% (CI 95%: 17%-85%). ATG in unrelated stem cell transplantation reduces the risk of severe acute and chronic GvHD and of graft failure without an obvious increase of severe infection. Further follow-up is mandatory to determine the incidence of late relapse.

Influence of Preharvest Tumor Cell Contamination in Bone Marrow or Blood Does Not Predict Resultant Tumor Cell Contamination of Granulocyte Colony-Stimulating Factor Mobilized Stem Cells

Tumor cell contamination of stem cell collections harvested from breast cancer patients is a common phenomenon described by several investigators but with findings that vary among reports. Although so-called co-mobilization of these cells has been hypothesized, the origin of tumor cell contamination in stem cells is still unknown. A total of 47 G-CSF mobilized stem cell grafts from patients with nodal-positive (n = 30), chemosensitive metastatic (n = 11), and 5 women with inflammatory breast cancer were evaluated for cancer cells by immunocytochemistry. Additionally, 40 bone marrow aspirations and 23 peripheral blood samples collected prior to apheresis and after one to two cycles of conventional chemotherapy were available for examination. Tumor cell contamination of leukapheresis correlated best with preharvest blood state. This was valid when the nominal (positive/negative) presence of tumor cells in blood was compared to the nominal presence of tumor cells in apheresis samples and when the it was correlated to the tumor cell load of apheresis samples (TCL = tumor cells per 10(6) nucleated cells investigated). The correlation between blood and stem cells was better (nominal and quantitative) than that between marrow and stem cells, despite the larger sample size of marrow aspirations. The presence or absence of cancer cells in apheresis samples could not be safely predicted by the presence or absence of tumor cells in marrow or blood alone. Diagnostic specificity seems to improve from a combination of results from marrow and blood analysis. No correlation was found in quantitative analysis of tumor cell contamination between marrow and blood. In conclusion, the results suggest that blood and bone marrow represent different compartments for epithelial cancer cells and that contaminating tumor cells in stem cell harvests may be derived from the blood and/or marrow compartment. The tumor cell contamination of a stem cell harvest cannot be safely predicted by a preceding blood or marrow analysis.

Urokinase-like plasminogen activator receptor expression on disseminated breast cancer cells

Disseminated tumor cells are detected frequently in bone marrow, peripheral blood, and cytokine-mobilized peripheral blood cell products of women undergoing high-dose therapy for breast cancer. Several attempts were made to purge autografts from contaminating cancer cells; however, the biological and clinical impact of these contaminations has not been clarified so far. Expression of distinct phenotypes is a surrogate marker for metastatic behavior of cancer cells. The expression of the urokinase-like plasminogen activator receptor seems to be a factor of high importance. It is not expressed by normal mammary tissue. Disseminated cancer cells from marrow, blood, and stem cell products have been investigated by double-stain technique for urokinase-like plasminogen activator receptor (uPA-R) expressing cytokeratin-positive cells. uPA-R(+)/CK(+) cells could be found in all qualities of samples; however, significantly less in G-CSF-mobilized peripheral blood stem cells compared to samples of other provenance (p = 0.02). It can be concluded that epithelial cells of malignant phenotype occur in blood, marrow, and autografts of breast cancer patients. Populations of disseminated tumor cells are phenotypically heterogeneous. Reduced uPA-R expression on cancer cells from leukapheresis samples might suggest a less aggressive nature of these cells compared to disseminated cells found in bone marrow. Furthermore, the data suggest that the phenotype of tumor cell contamination in leukapheresis products differs significantly from those of disseminated cancer cells in bone marrow or blood.

Comparison of total body irradiation vs busulfan in combination with cyclophosphamide as conditioning for unrelated stem cell transplantation in CML patients

We compared fractionated total body irradiation (12 Gy)/cyclophosphamide (120 mg/kg) with busulfan (16 mg/kg)/cyclophosphamide (120 mg/kg) as preparative therapy in unrelated donor stem cell transplantation of CML patients. Fifty patients with CML (1.CP = 46; aP = 4) and a median age of 36 years (range 16-52) were enrolled in this sequential trial between 1994 and 1999. In both groups patients were well balanced with respect to age, disease status, stem cell source and CMV status. All patients received standard doses of cyclosporin A, methotrexate and anti-thymocyte globulin (ATG) as GVHD prophylaxis. No graft failures occurred in either group. The median day of leukocyte engraftment was earlier in the Bu/Cy than in the TBI/Cy group (day 15 vs 17; P = 0.006). The incidence of grade II-IV GVHD was 40% in the TBI/Cy and 36% in the Bu/Cy group, whereas severe grade III/IV GVHD was only observed in 12% of patients in both groups. The incidence of chronic GVHD (limited and extensive) at 1 year was higher in the Bu/Cy arm (65% vs 30%; P = 0.02). More toxicity grade I/II of the liver (88% vs 44%; P = 0.002) and more hemorrhagic cystitis (32% vs 8%; P = 0.02) were observed in the Bu/Cy regimen. Seven relapses in the TBI and no relapse in the Bu/Cy group were observed after a median follow-up of 44 and 15 months, respectively. The estimated 3 year OS and DFS was 72% (95% CI: 55-98%) and 58% (95% CI: 39-77%) in the TBI and 70% (95% CI: 51-89%) for DFS and OS in the Bu/Cy group. We conclude that the anti-leukemic effect of the Bu/Cy regimen seems to be at least as effective as the TBI/Cy combination in unrelated stem cell transplantation of CML patients, with no graft failures, but that it correlates with a higher incidence of liver toxicity, hemorrhagic cystitis and chronic GVHD. Longer follow-up is necessary to determine the late relapse rate and late toxicity.