Long-term follow-up of high-dose chemotherapy with autologous stem-cell transplantation and response-adapted whole-brain radiotherapy for newly diagnosed primary CNS lymphoma: results of the multicenter Ostdeutsche Studiengruppe Hamatologie und Onkologie OSHO-53 phase II study.

BACKGROUND: We previously reported the results of a phase II study for patients with newly diagnosed primary central nervous system lymphoma treated with autologous peripheral blood stem-cell transplantation (aPBSCT) and response-adapted whole-brain radiotherapy (WBRT). Now, we update the initial results. PATIENTS AND METHODS: From 1999 to 2004, 23 patients received high-dose methotrexate. In case of at least partial remission, high-dose busulfan/thiotepa (HD-BuTT) followed by aPBSCT was carried out. Patients refractory to induction or without complete remission after HD-BuTT received WBRT. Eight patients still alive in 2011 were contacted and Mini-Mental State Examination (MMSE) and the European Organisation for Research and Treatment of Cancer quality-of-life questionnaire (QLQ)-C30 were carried out. RESULTS: Of eight patients still alive, median follow-up is 116.9 months. Only one of nine irradiated patients is still alive with a severe neurologic deficit. In seven of eight patients treated with HD-BuTT, health condition and quality of life are excellent. MMSE and QLQ-C30 showed remarkably good results in patients who did not receive WBRT. All of them have a Karnofsky score of 90%-100%. CONCLUSIONS: Follow-up shows an overall survival of 35%. In six of seven patients where WBRT could be avoided, no long-term neurotoxicity has been observed and all patients have an excellent quality of life.

The modification of high-dose therapy shortens the duration of neutropaenia by delay of leucocyte nadir.

Infections during neutropaenia contribute still significantly to mortality and morbidity after high-dose therapy and autologous stem cell transplantation. Further acceleration of haemopoietic recovery seems impossible for biological reasons. Another approach to shorten neutropaenia could be to remove drugs from high-dose therapy protocols with strong contribution to immunosuppression and neutropaenia and unproven antineoplastic activity. In this retrospective matched-pair analysis, conventional busulphan/cyclophosphamide (Bu/Cy) high-dose therapy was compared to single-agent busulphan conditioning before autologous stem cell transplantation. This modification led to a significant shorter neutropaenic interval by protraction of cell decrease and to a significant mitigation of neutropaenia. After single-agent busulphan conditioning, leucocytes dropped below 1/nl at median 1.5 days later when compared to the patients from the busulphanBu/Cy control group (P=0.001). In a significant percentage of patients (n=6, 60%) leucocytes did not fall below 0.5 cells/nl at any time. In contrast, all patients from the Bu/Cy control group experienced deep neutropaenia (P=0.004). Thrombocytopaenia and requirement for transfusions of platelets or red cells were not influenced. Antineoplastic activity seemed to be preserved as determined by survival analysis. In conclusion, modification of high-dose regimen with the intention to shorten neutropaenia with preserved antitumour activity could be an approach to reduce infection-related morbidity and mortality and to consider economic necessities.

Disruption of the BCL11B gene through inv(14)(q11.2q32.31) results in the expression of BCL11B-TRDC fusion transcripts and is associated with the absence of wild-type BCL11B transcripts in T-ALL.

T-cell acute lymphoblastic leukemia (T-ALL) is associated with chromosomal aberrations characterized by juxtaposition of proto-oncogenes to T-cell receptor gene loci (TCR), resulting in the deregulated transcription of these proto-oncogenes. Here, we describe the molecular characterization of a novel chromosomal aberration, inv(14)(q11.2q32.31), in a T-ALL sample, involving the recently described BCL11B gene and the TCRD locus. The inversion joined the 5' part of BCL11B, including exons 1-3, to the TRDD3 gene segment of the TCRD locus, whereas the reciprocal breakpoint fused the TRDV1 gene segment to the fourth exon of BCL11B. The TRDV1-BCL11B joining region was 1344 bp long and contained fragments derived from 20q11.22, 3p21.33 and from 11p12, indicating the complex character of this aberration. A strong expression of in-frame transcripts with truncated BCL11B and TCRD constant region (TRDC) were observed, but in contrast to normal T cells and other T-ALL samples, no wild-type BCL11B transcripts were detected in the T-ALL sample. Screening of 37 other T-ALLs revealed one additional case with expression of the BCL11B-TRDC fusion transcript. As BCL11B appears to play a key role in T-cell differentiation, BCL11B disruption and disturbed expression may contribute to the development of T-cell malignancies in man.

A solid-phase radioimmunoassay for Epstein-Barr virus-associated membrane antigen prepared from B95-8 cell culture supernatants.

Epstein-Barr virus(EBV)-associated membrane antigen (MA) was concentrated from B95-8 cell culture media by precipitation with polyethylene glycol followed by chromatography on Bio-Gel A-50m. In a RAJI cell-binding assay, MA-positive material could only be found in the void volume of the column. After ultracentrifugation all antigenic activity appeared in the pellet, which suggested that MA was present in aggregates, presumably fragments of cellular membranes and/or virus envelopes. The MA-containing preparation was photopolymerized in polyacrylamide gel. The homogenized gel was used in a solidphase radioimmunoassay with 125l-labeled IgG from an Anti-MA positive reference serum and an anti-MA negative control serum. The specificity of the reaction was confirmed in blocking tests with anti-EBV positive and negative sera. A good correlation was found between the results obtained in the radioimmunoassay and the results obtained in direct immunofluorescence tests for the detection of MA. The existence of at least two subspecificities of the MA complex could be confirmed by this radioimmunoassay.

Detection of minimal residual disease.

A high percentage of patients with leukemia, lymphoma, and solid tumors achieve a complete clinical remission after initial treatment, but the majority of these patients will finally relapse from residual tumor cells detectable in clinical remission only by the most sensitive methods. The in vitro amplification of tumor-specific DNA or RNA sequences by polymerase chain reaction (PCR) allows identification of a few neoplastic cells in 10(4) to 10(6) normal cells. Depending on the underlying malignant disease and therapeutic treatment, the presence of residual tumor cells in an individual patient may herald relapse, but a long-term stable situation or slowly vanishing tumor cells are also possible. Molecular monitoring of residual leukemia and lymphoma cells by quantitative PCR techniques has provided important information about the effectiveness of treatment and the risk of recurrent disease as shown by minimal residual disease (MRD) analysis in patients with various malignant diseases. Such diseases include childhood acute lymphoblastic leukemia, after induction therapy; acute promyelocytic leukemia, during and after chemotherapy; and chronic myelogenous leukemia, during treatment with alpha-interferon and after allogeneic bone marrow transplantation. Evaluation of the predictive value of the detection of MRD has to take into account its evolution and course, the pathogenesis, biology, and natural course of the underlying malignant disease, the molecular genetic lesion, and finally, the type of treatment. Quantification of minimal residual cells by the recently developed real-time quantitative PCR technique will surely have a major impact on our therapeutic strategies for patients with leukemia, lymphomas, and solid tumors. Based on quantitative PCR data, the terms molecular remission and molecular relapse have to be exactly defined and validated in prospective clinical trials to assess the biological and clinical significance of MRD in various types of malignancies.

Persistence of circulating t(14;18)-positive cells in long-term remission after radiation therapy for localized-stage follicular lymphoma.

PURPOSE: To determine the prevalence of circulating t(14;18)-positive cells in patients with long-term remission after radiation therapy for stage I and II follicular lymphoma. PATIENTS AND METHODS: Peripheral-blood mononuclear cells from 21 patients in continuous remission were examined by a two-step polymerase chain reaction (PCR) assay for the detection of cells carrying a t(14;18) translocation with a breakpoint within the major breakpoint region (MBR) or minor cluster region (mcr). RESULTS: Follow-up duration was between 25 and 160 months, with a median of 6.5 years. Thirteen patients (62%) showed negative results on repetitive testing. Cells that were t(14;18)-positive were found in eight patients (38%), all carrying a breakpoint in the MBR. One patient relapsed in each group. CONCLUSION: Circulating t(14;18)-positive cells can persist in a high percentage of follicular lymphoma patients in long-term complete remission (CR) after radiation treatment for stage I and II disease. The significance of minimal residual t(14;18)-positive cells with regard to the risk of relapse needs to be investigated in further prospective long-term studies.

BCL-2/JH rearrangements in circulating B cells of healthy blood donors and patients with nonmalignant diseases.

PURPOSE: To answer the question whether t(14;18)-positive cells can be detected by polymerase chain reaction (PCR) in the peripheral blood of healthy blood donors and patients with nonmalignant diseases. PATIENTS AND METHODS: Peripheral-blood mononuclear cells (PBMNC) from healthy donors (n = 36) and patients with nonmalignant diseases (n = 21) were examined by two-step PCR for the detection of t(14;18)-positive cells with a breakpoint within the major breakpoint region (MBR). Approximate numbers of t(14;18)-positive cells were determined using limiting dilution assays, as well as the stochastic multiple-tube approach. RESULTS: We were able to detect t(14;18)-positive cells in PBMNC of approximately 50% of healthy donors and patients with nonmalignant diseases if DNA amounts up to 10 microg were tested. Compared with 17 t(14;18)-positive patients being in complete remission after radiotherapy for low-stage malignant follicular lymphoma, the majority of 26 healthy donors were found to have significantly lower numbers of t(14;18)-positive cells circulating in the peripheral blood. In the case of six healthy donors, more than one t(14;18) DNA fragment based on size and nucleotide sequence analysis was detected. In one healthy individual, four different t(14;18)-positive cell clones were found in nine samples found over 5 years. CONCLUSION: The occurrence of the t(14;18) translocation is not restricted to follicular lymphoma cells. In healthy donors, long-lived t(14;18)-positive cells can be detected by PCR if the sensitivity is high enough. Based on nucleotide sequence analysis, the t(14;18) DNA fragments detected in healthy donors cannot be distinguished from those found in follicular lymphomas.

Dose-response relationship of complementary radiotherapy following four cycles of combination chemotherapy in intermediate-stage Hodgkin's disease.

PURPOSE: To determine the appropriate irradiation dose after four cycles of modern combination chemotherapy in nonbulky involved field (IF/BF) and noninvolved extended-field (EF/IF) sites in patients with intermediate-stage Hodgkin's disease (HD). MATERIALS AND METHODS: HD patients in stage I to IIIA with a large mediastinal mass, E stage, or massive spleen involvement were treated with two double cycles of alternating cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) plus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) followed by EF irradiation in two successive trials (HD1 and HD5). In the HD1 trial (1983 to 1988), 146 patients who responded to chemotherapy were randomized to receive 20 Gy (70 patients) or 40 Gy (76 patients) of EF irradiation in all fields outside bulky disease sites. A cohort of 111 patients who fulfilled the same inclusion criteria in the subsequent trial HD5 (1988 to 1993) were treated with 30 Gy. Bulky disease always received 40 Gy. RESULTS: Freedom-from-treatment-failure (FFTF) and survival (SV) curves showed no differences between the 20-, 30-, and 40-Gy groups. However, acute toxicities were more frequent in the 40-Gy arm. Analysis of relapse patterns showed that 18 of 26 relapsing patients either failed to respond in initial bulky sites (n = 5) or had an extranodal relapse (n = 9) or both (n = 4). After 5 years, the cumulative risk for relapse in bulky sites is 10%, despite 40 Gy of radiation. CONCLUSION: Our results strongly suggest that there is no relevant radiotherapy dose effect in the range between 20 Gy and 40 Gy in IF/BF and EF/IF after 4 months of modern polychemotherapy in patients with intermediate-stage HD. Relapse patterns indicate that patients destined to relapse need more systemic, rather than local, treatment. Based on our data, we conclude that 20 Gy is sufficient in EF/IF of intermediate-stage HD following four cycles of modern polychemotherapy.

In vitro and in vivo effects of synthetic ribozymes targeted against BCR/ABL mRNA.

Chronic myelogenous leukemia (CML) is associated with a translocation of the BCR and the ABL genes, t(9;22). Results of this event are transcription and translation products that are unique to malignant cells. We therefore designed synthetic ribozymes which are capable of exclusively cleaving the BCR/ABL B3A2-type mRNA without altering normal cellular transcripts. Synthetic B3A2-type transcripts could only be cleaved by B3A2-type mRNA targeted ribozymes and not by any of the controls. The B3A2-type mRNA directed ribozyme, on the other hand, did not cleave any of the control transcripts. The effective delivery of ribonucleic acids by lipofection into K562 cells could be demonstrated by fluorescent microscopy, slot blot analysis, and RNA polyacrylamide gel electrophoresis. In vivo, we were able to induce a significant inhibition of the proliferation of K562 cells with ribozymes directed against the B3A2-type mRNA. Quantitative PCR analyses showed an up to fivefold reduction of the relative number of BCR/ABL mRNA molecules per single cell after exposure to ribozymes compared to controls. We conclude that ribozymes targeted against the B3A2-type BCR/ABL mRNA function in vitro and in vivo.

Expression of interleukin 10 in B lymphocytes of different origin.

Interleukin 10 (IL-10) is a strong B-cell-activating factor. Since murine Ly1-positive peritoneal or lymphoma B cells strongly express IL-10, we examined malignant cells from patients with acute and chronic leukemias by reverse transcriptase polymerase chain reaction (RT-PCR) for the expression of IL-10 mRNA. High expression was found in three out of four samples from CD10+, CD5- common acute lymphoblastic leukemia (cALL) cells, whereas T-ALL samples generally did not contain IL-10 mRNA. In contrast to the murine system, only low levels of IL-10 expression were seen in 10 out of 11 samples from patients with CD5+ CLL. Myeloid derived cell lines were negative for IL-10. Epstein Barr virus (EBV) positive and negative Burkitt's lymphoma (BL) cell lines showed heterogenous IL-10 expression: BL cell lines with a nonactivated germinal center phenotype (CD10+, CD77+, CD23-, CD30-, CDw70-) expressed little or no IL-10, whereas EBV-positive and negative BL cell lines with an activated phenotype (CD77-, CD23+, CD30+, CDw70+) expressed easily detectable amounts of IL-10 mRNA. The highest expression of IL-10 was found in EBV-immortalized lymphoblastoid cell lines (LCL). Upon superinfection with non-defective EBV, the EBV-negative cell line BL 41 up-regulated IL-10 expression. Thus, in vivo IL-10 expression is not restricted to cells showing a specific (CD5+) phenotype. IL-10 may play an important role in c-ALL. The expression of IL-10 in BL cell lines is correlated to an activated phenotype in vitro and is independent of the EBV carrier status. EBV can induce IL-10 expression.

Translocation t(8;13) in a patient with T cell lymphoma and features of a myeloproliferative syndrome.

A 32-year-old white woman was admitted with a diagnosis of T lymphoblastic lymphoma and a bone marrow and peripheral blood cytology that was suggestive of a myeloproliferative syndrome (MPS). In addition, islets of myeloid precursors were found in the lymph node where the lymphoma had been diagnosed. Cytogenetic examination was negative for the Philadelphia chromosome (Ph) as well as the RT-PCR for bcr/abl rearrangement, but surprisingly a t(8;13)(q10;p10) was detected. To our knowledge, this translocation has not been reported in such a clinical setting. The patient was treated for the lymphoblastic lymphoma and underwent autologous bone marrow transplantation. She has been in complete remission since induction chemotherapy with a Karnofsky score of 100%. The difficulty of classifying this case is discussed.

Serum levels of circulating ICAM-1 are increased in Hodgkin's disease.

The intercellular adhesion molecule 1 (ICAM-1) is the ligand for the lymphocyte function-associated antigen 1 (LFA-1). The ICAM-1/LFA-1 complex mediates cell-cell and cell-matrix interactions and is believed to be crucial for several immunological functions, including non-MHC-restricted cytotoxicity. Recently, a circulating form of the surface ICAM-1 molecule, the 82 kDa cICAM, has been identified. Using enzyme-linked immunosorbent assay (ELISA) we have examined 82 kDa cICAM-1 levels in the sera of 45 age- and sex-matched healthy subjects and 130 consecutive patients with Hodgkin's disease (HD). The mean +/- SD concentration of the 82 kDa cICAM-1 was significantly higher (p < 0.001) in HD patients (725.6 +/- 141 ng/ml) than in healthy controls (403.5 +/- 54.5 ng/ml). Patients with B-symptoms (n = 66) had higher cICAM-1 levels than patients without systemic symptoms (n = 64) (825.1 +/- 202.9 ng/ml versus 671.7 +/- 164.9 ng/ml; p < 0.001). Serum levels of cICAM-1 were also significantly higher (p < 0.05) in patients with disseminated disease (stage III and IV) than in those with localized disease (stage I and II). The HD patients in stage III and IV with B-symptoms had significantly higher (p < 0.001 and p < 0.02, respectively) cICAM-1 levels then stage III/IV patients lacking B-symptoms. The increase of cICAM-1 concentrations was positively correlated to increases of soluble receptors for interleukin-2 (sIL-2R) (r = 0.69; p < 0.001). Since cICAM-1 is functionally able to bind to LFA-1, increased serum levels of this molecule could be a mechanism for promoting de-adhesion and inability of Hodgkin and Reed-Sternberg cells (H-RS) to be recognized by cytotoxic effector cells, and could thus represent a way for these cells to escape immunosurveillance and for progression and spreading of disease.

The significance of serum levels of soluble 60kDa receptors for tumor necrosis factor in patients with Hodgkin's disease.

Soluble forms of the two molecular species of the cell surface receptors (Rs) for tumor necrosis factor (TNF) have been detected in normal urine and serum including type I and type II TNF-Rs. Using enzyme-linked immunosorbent assay we have determined type I 60 kDa sTNF-R levels in the sera of 45 age- and sex-matched healthy subjects and 106 patients with Hodgkin's disease (HD). HD patients were either previously untreated (n = 76) or were in complete remission for at least 3 years after remission induction treatment (n = 30). The mean +/- SD concentrations of the 60 kDa type sTNF-R were significantly higher in HD patients than in healthy controls (1.32 +/- 0.19 ng/ml versus 0.6 +/- 0.13 ng/ml; p < 0.001). The extent of increase correlated with the disease stage. Soluble 60 KDa TNF-Rs were found to be significantly higher in stage III and IV (1.42 +/- 0.21 ng/ml) than in stages I and II (1.08 +/- 0.15 ng/ml). Patients with B-symptoms (n = 33) had higher levels (1.67 +/- 0.20 ng/ml) than patients without systemic symptoms (1.02 +/- 0.11 ng/ml; p < 0.001). In 52 patients evaluable for response, the complete remission (CR) rate of patients with 60 kDa sTNF-Rs < 1.2 ng/ml was higher (88%) than in those with 60 kDa sTNF-Rs > 1.2 ng/ml (64%; p < 0.01). A significant increase in serum levels of 60 kDa sTNF-R levels was also observed in HD patients in long-standing CR (1.04 +/- 0.10 ng/ml). Our data suggest that the pretreatment serum concentration of 60 kDa sTNF-Rs in HD may bear prognostic relevance. Increased 60 kDa sTNF-R levels seen in HD patients in remission may point to the defect in cellular immunity characteristic of HD patients.

Comparison of different ribozymes for efficient and specific cleavage of BCR/ABL related mRNAs.

In chronic myelogenous leukemia (CML) the reciprocal translocation of the long arms of chromosomes results in the formation of the unique BCR/ABL fusion gene which is believed to play a crucial role in the pathogenesis of CML. Different short synthetic ribozyme constructs were compared with regard to their efficiency to cleave the BCR/ABL target RNA. In the CML cell line K562 we were able to inhibit the p210BCR/ABL synthesis by a ribozyme which was about twofold more effective than the corresponding antisense molecule.

Enzyme-linked immunosorbent assay for IgG antibodies to Epstein-Barr virus-associated early antigens and viral capsid antigen.

An enzyme-linked immunosorbent assay has been developed for the detection of IgG antibodies to Epstein-Barr virus-associated early antigens and late antigens including the viral capsid antigen. The antibody titers of human sera determined in this way correlate well with those by indirect immunofluorescence. ELISA was more sensitive than the IF method. The assays described may be used for rapid and sensitive diagnosis of EBV-related diseases. In addition, the ELISA will be useful for the determination of antibody titers to isolated EBV-associated antigens, e.g., purified components of the EA complex.

Detection of IgA antibodies to Epstein-Barr virus-associated antigens by ELISA.

The detection of IgA antibodies to the Epstein-Barr virus (EBV)-associated viral capsid antigen (VCA) and early antigens (EA) is of diagnostic and prognostic importance for patients with nasopharyngeal carcinoma (NPC). An ELISA for the determination of serum IgG antibodies to these antigens has been developed which uses the double antibody method. 136 sera obtained from healthy donors and patients with non-EBV related tumors and lymphomas were tested by ELISA; only 3 sera, from patients with chronic lymphatic leukemia, hairy cell leukemia and Burkitt-like lymphoma, contained antibodies of IgA class to VCA and EA. Ninety-five sera from patients suspected of having NPC were tested. IgA anti-VCA was found in 28 sera (29.5%), 12 of which also contained IgA anti-EA. The assays described are suitable for diagnosis and follow-up of patients with EBV-associated nasopharyngeal carcinoma. Furthermore, isolated EA components may be tested for their reactivity with IgA antibodies, as was shown for the 60 kDa polypeptide associated with the EA complex.

Quantitative detection of t(14;18)-positive cells by real-time quantitative PCR using fluorogenic probes.

To detect t(14;18)-positive cells present in human lymphoma tissue, bone marrow aspirates and peripheral blood mononuclear cells (PBMNC), we have established an automated, real-time quantitative PCR using double-labeled fluorogenic probes. In relation to t(14;18)-positive genomic DNA or a cloned t(14;18)-DNA fragment, highly reproducible results can be obtained with initial copy numbers between 10 to 10(5). The detection of single copies has been verified by the stochastic multiple-tube approach. PBMNC cells obtained during clinical follow-up of patients with follicular lymphoma were analyzed by the one-step, real-time quantitative PCR and a two-step, semi-nested PCR combined with a limiting dilution assay. The quantitative results obtained by both assays correlate very well. Real-time quantitative PCR has several advantages: (i) it involves less critical pipetting steps, (ii) is less time-consuming and (iii) UTP, in combination with uracil-N-glycosylase, can be used to control carryover contamination. The higher specificity is due to optimized primer annealing conditions and MgCl2 concentration and the use of AmpliTaq Gold. The sensitivity is at least as high as by the two-step PCR. Real-time quantitative PCR will be very helpful in large epidemiological studies and in research for molecular staging and the detection of minimal residual tumor cells, including the analysis of blood stem-cell preparations to be used for transplantation after myelo-ablative therapy.

An improved strategy and a useful housekeeping gene for RNA analysis from formalin-fixed, paraffin-embedded tissues by PCR.

Specific amplification of nucleic acid sequences by PCR has been extensively used for the detection of gene rearrangements and gene expression. Although successful amplification of DNA sequences has been carried out with DNA prepared from formalin-fixed, paraffin-embedded (FFPE) tissues, there are only a few reports regarding RNA analysis in this kind of material. We describe a procedure for RNA extraction from different types of FFPE tissues, involving digestion with proteinase K followed by guanidinium-thiocyanate acid phenol extraction and DNase I digestion. These RNA preparations are suitable for PCR analysis of mRNA and even of intronless genes. Furthermore, the universally expressed porphobilinogen deaminase mRNA proved to be useful as a positive control because of the lack of pseudogenes.

Quantitative detection of t(14;18)-positive cells in patients with follicular lymphoma before and after autologous bone marrow transplantation.

The aim of this study was to evaluate whether a quantitative analysis of circulating t(14;18)-positive cells is of prognostic significance in patients with follicular lymphoma (FL) after myelo-ablative therapy supported by ABMT. We tested DNA from primary lymphoma tissue as well as PBMC before and after ABMT from 15 patients for the presence of the t(14;18) translocation. Nine patients showed a t(14;18) translocation, six patients were t(14;18)-negative. Circulating t(14;18)-positive cells of seven patients were quantitatively determined by limiting dilution assays combined with a two-step PCR and by real-time quantitative PCR. The results of both methods correlate very well. The number of circulating t(14;18)-positive cells decreased significantly in all patients after myeloablative therapy and ABMT, t(14;18)-negative blood samples were found in five of seven patients. In all patients circulating t(14;18)-positive cells reappeared within 2 years after ABMT showing two different patterns. During continuous CR the numbers of circulating t(14;18)-positive cells were found to be stable within one order of magnitude. In contrast, in one patient the relapse was accompanied by a logarithmic increase of t(14;18)-positive cells. In a second patient the enlargement of lymph nodes developing over a period of 12 months was accompanied by very slowly increasing numbers of t(14;18)-positive cells. In all cases where diagnostic lymph node tissue was available, the same t(14;18) translocation was found at first diagnosis and after ABMT as shown by nucleotide sequence analysis. We conclude that the quantitative detection of circulating t(14;18)-positive cells during follow-up of patients with FL after ABMT reflects the clinical course of the disease. Relapses are associated with increasing numbers of circulating t(14;18)-positive cells and continuous complete remissions with stable cell counts.

Chemotherapy for mobilisation of Ph-negative progenitor cells from patients with CML: impact of different mobilisation regimens.

Mobilised peripheral blood stem cells are widely used for autografting in patients with chronic myeloid leukaemia (CML) and it is generally thought that a high proportion of Ph-negative progenitor cells in the graft is desirable. We report here the results of 91 stem cell mobilisations performed with various chemotherapy regimens followed by G-CSF. We show that mobilisation of Ph-negative cells is possible after diagnosis as well as in advanced stages of the disease. The yield of Ph-negative cells is highly dependent on the chemotherapy regimen: while the combination of idarubicin and cytarabin for 3-5 days (IC3-5) mobilised Ph-negative cells in most patients, high-dose cyclophosphamide was ineffective. Mobilisation of Ph-negative progenitor cells after IC3 was at least as effective as after IC5; however, less apheresis sessions were required, and toxicity was much reduced after IC3. Compared to historical controls, IC was equally effective as the widely used ICE/miniICE (idarubicin, cytarabin, etoposide) protocol. No correlation was found between graft quality and the cytogenetic response to subsequent treatment with interferon-alpha. We conclude that IC3 is an effective and well-tolerated regimen for mobilising Ph-negative cells that compares well with more aggressive approaches such as IC5 and ICE/miniICE.