High-dose chemotherapy in germ cell tumours: a large single centre experience

High-dose chemotherapy (HDCT) has evolved as a strategy to improve the treatment outcome in patients with relapsed and/or refractory germ cell tumours. Between August 1989 and September 1995, 150 consecutive patients with relapsed and/or refractory germ cell tumours were treated with conventional-dose salvage chemotherapy followed by one cycle of HDCT with carboplatin 1500-2000 mg/m2, etoposide 1200-2400 mg/m2 and ifosfamide 0-10 g/m2 and were retrospectively analysed. With a median follow-up time of 55 months (range 21-88 months) 51/150 (34%) patients are alive and disease free. The projected event-free and overall survival are 29% (confidence interval 22-37%) and 39% (confidence interval 31-47%) respectively. The relevance of prognostic variables for long-term survival after HDCT were prospectively confirmed. Persisting toxicities occurred in approximately one third of the long-term survivors. Treatment intensification with HDCT resulted in a significant proportion of the long-term survivors in patients with relapsed and/or refractory germ cell tumours. Trials to prospectively evaluate HDCT as an early intervention in these patients seem justified.

Detection of tumor cells in peripheral blood samples from patients with germ cell tumors using immunocytochemical and reverse transcriptase-polymerase chain reaction techniques

The aim of this study was to establish sensitive techniques for the detection of residual germ cell tumor cells in peripheral blood and progenitor cell harvests. For this purpose, we used immunocytochemical staining for cytokeratin filaments and reverse transcriptase-polymerase chain reaction (RT-PCR) for epidermal growth factor receptor (EGF-R) and germ cell alkaline phosphatase (GCAP). Germ cell tumor lines Tera-1 and Tera-2 were titrated into normal peripheral blood. Immunocytochemical staining allowed detection of one cytokeratin-positive tumor cell in 10(5) cells. RT-PCR for EGF-R revealed one tumor cell in 10 cells for Tera-1 and one tumor cell in 10(3) cells for Tera-2, while RT-PCR for GCAP displayed a sensitivity of one tumor cell in 10(6) cells for Tera-1, one tumor cell in 10(4) cells for Tera-2, and no positivity in normal mononuclear cells (n = 20) and progenitor cell harvests (n = 5). The analysis of peripheral blood and progenitor cell harvests from 20 patients with germ cell tumors revealed tumor cell contamination in three patients using immunocytochemical staining and in seven patients by RT-PCR for GCAP. We conclude that RT-PCR for GCAP appears to be suitable for the sensitive detection of residual germ cell tumor cells in peripheral blood and progenitor cell harvests.

Treatment of relapse after allogeneic bone marrow transplantation with unmanipulated G-CSF-mobilized peripheral blood stem cell preparation

Donor lymphocyte infusions (DLI) are an effective treatment of leukemia relapse after allogeneic bone marrow transplantation. Undesired side-effects are the development of graft-versus-host disease (GVHD) and the occurrence of pancytopenia in some patients. In a pilot study, we investigated if unmanipulated G-CSF-mobilized peripheral blood stem cells which naturally contain large numbers of T lymphocytes (D-PBSC/LI) would be equally effective or even superior than DLI in generating a graft-versus-leukemia reaction (GVL) but could mitigate or prevent the development of pancytopenia. We treated 12 patients with CML chronic phase (n = 5), CML blast crisis (n = 2), AML (n = 2), ALL (n = 1), CLL (n = 1) and multiple myeloma (n = 1). In five patients with acute leukemia or CML blast crisis D-PBSC/LI followed intensive chemotherapy (group A), in seven patients D-PBSC/LI were given without any prior chemotherapy (group B). In group A two patients were evaluable for hematologic toxicity. Leukopenia <1000/microl lasted for 10 and 19 days, and thrombocytopenia <20,000/microl for 11 and 13 days, respectively. In group B leukopenia <1000/microl and thrombocytopenia <20,000/microl was observed in only one patient. Moderate cytopenia developed in four of five evaluable patients. A complete remission could be achieved in all seven patients with CML who all developed acute and/or chronic GVHD. None of the remaining five patients achieved a complete remission despite acute and/or chronic GVHD in two of them. Four patients died from disease progression, one patient from a secondary lymphoma, and one patient as a result of uncontrolled GVHD. In conclusion, D-PBSC/LI is effective in inducing GVL reaction but it does not prevent pancytopenia in each case. It remains unclear if it mitigates the incidence and severity of pancytopenia.

Human herpesvirus type 6 variants identified by single-strand conformation polymorphism analysis

Six human herpesvirus 6 (HHV-6) variants were analyzed for heterogeneity using the polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP). Two independent DNA regions were selected: a fragment of the gene U11 (position 18966-21578) coding for a basic phosphoprotein, the major antigenic structural protein pp100; and a fragment from an open reading frame (ORF) area of the gene U67, previously referred to as 13R (position 102458-103519), coding for a product of unknown function. The two PCR systems based on the above DNA sequences yielded products of 187 bp and 223 bp, respectively. DNA obtained from three laboratory reference strains (U1102, R104 and St.W.) and from HHV-6 infected peripheral white blood cells of bone marrow transplant patients and blood donors was used to test the applicability of two different SSCP analysis systems for the identification of HHV-6 variants using amplicons derived by PCR from the two genomic regions described above (U11 [pp100], U67 [13R-ORF]). The generation of characteristic SSCP patterns enables the rapid differentiation of HHV-6 A and B strains for the classification of variants derived from clinical samples, reducing the need for expensive and time-consuming direct sequencing analyses.

High-dose chemotherapy with autologous stem cell support in poor-risk germ cell tumors

High-dose chemotherapy (HDT) and stem cell transplantation is a newer treatment option widely applied in poor-risk germ cell tumor patients. Due to the increasing practical clinical experience and the availability of hematopoietic growth factors, this treatment approach has become a relatively safe procedure. Depending on the drugs used. the most prominent therapy-associated side effects are myelosuppression, infections, mucositis, moderate, mostly reversible neurotoxicity, and renal impairment. Because of their unique pharmacologic characteristics, carboplatin and etoposide have proved to be the most important drugs for HDT. It is not known whether the addition of ifosfamide or cyclophosphamide or other drugs to the combination of carboplatin and etoposide leads to superior results. It is not yet clear if HDT should already be instituted in first-line treatment of poor-risk patients, or later after relapse or incomplete response. Even if precise data on the therapeutic value of HDT are still missing because randomized trials are not yet ready for evaluation, there is good evidence for the effectiveness of HDT. The demonstration of remissions in cisplatin-refractory patients, the inversion of remission durations, and the induction of long-term freedom from disease in multiply relapsed patients who were deemed incurable with conventional-dose procedures argue in favor of HDT. Finally, the delineation of prognostic factors associated with a poor probability of survival after HDT contributes to the selection of patients who are likely to profit from HDT and those who should be spared from dose-intensive treatment.

Germ cell tumors: dose-intensive therapy

Dose intensive chemotherapy in germ cell tumor patients has become a relatively safe procedure after the introduction of growth factors and the availability of autologous stem cells for hematopoietic rescue. Carboplatin and etoposide are the most active drugs available today, and are given in one or two subsequent cycles at dosages between 1000 and 2000 mg/m2 and 1200 and 2400 mg/m2, respectively. The potency of this approach is shown by the induction of long-term disease-free survival in a small proportion of patients with multiply relapsed or far advanced disease, deemed incurable with conventional chemotherapy. This observation indicates that cisplatin refractoriness can be overcome by high-dose carboplatin and etoposide. High-dose treatment (HDT) instituted earlier in the course of the disease, ie, for first-line salvage or even in first-line treatment of poor risk patients is better tolerated and is hoped to lead to superior tumor eradication. The value of HDT needs to be determined in randomized studies, some of which are under way.

Herpes simplex infection of the jejunum occurring in the early post-transplantation period

Reactivation of infections with herpes viruses is a frequent and major cause of morbidity after bone marrow transplantation. In this case report we stress that HSV infections of the colon and small intestine should be considered in the differential diagnosis of diarrhea and intestinal bleeding in the early post-transplantation period. Severe acute GVHD and subsequent intensive immunosuppressive treatment may increase the risk for reactivation of HSV infection particularly in situations in which acyclovir prophylaxis has been omitted.

High-dose chemotherapy with carboplatin, etoposide and ifosfamide followed by autologous stem cell rescue in patients with relapsed or refractory malignant lymphomas: a phase I/II study

Patients with relapsed or refractory non-Hodgkin's lymphomas (NHL) and Hodgkin's disease (HD) with recurrences after an anthracyclin-containing regimen only have a chance of cure of below 10% with conventional chemotherapy. In order to improve their prognosis, we started a phase I/II trial using high-dose therapy comprising carboplatin, together with etoposide and ifosfamide (CEI), followed by autologous stem cell rescue (ASCR) as consolidation after salvage treatment. Since September 1990, 40 patients with intensively pretreated advanced NHL (n = 24) or HD (n = 16) received one cycle of high-dose therapy (HDT) consisting of carboplatin 1500 mg/m2, ifosfamide 10 g/m2 and etoposide in escalating doses from 1200 mg/m2 to 2400 mg/m2 followed by ASCR. Thirty-nine patients were assessable for toxicity and response. The following doses appeared to be safe: carboplatin 1500 mg/m2, etoposide 2400 mg/m2 and ifosfamide 10 g/m2. All patients developed grade 3 nausea and grade 3 or 4 mucositis. Granulocytopenic fever occurred in 100% with grade 4 infections in 15%. Mild transient kidney toxicity was noted in 36% and liver toxicity in 20% of patients. One toxic death occurred (2.5%). Objective responses were obtained in 36 of 39 patients (92%) with complete remissions (CR) in 24 patients (61.5%) and partial remissions (PR) in 12 (30.7%). Median observation time for surviving patients was 23.3 months (range 3.4-52.3). The probabilities of overall, event-free and relapse-free survival at 2 years are 62, 39 and 55%, respectively. Patients with primary refractory disease or resistant relapse had a poor prognosis. High-dose carboplatin, etoposide and ifosfamide plus autologous stem cell rescue represents an effective, potentially curative salvage treatment with acceptable toxicities.

[High-dose chemotherapy and reinfusion of hematopoietic stem cells in advanced germ cells tumors with poor prognosis--the position in 1996]

High-dose chemotherapy (HDCT) is a promising treatment for patients with germ cell tumours and a poor prognosis. The selection of patients who may profit from this intervention is challenging for the urologist, as the indication has to be carefully established. Exclusion criteria primarily concern impaired organ functions. Prior to HDCT haematopoietic stem cells are obtained after the administration of conventional-dose chemotherapy plus G- or GM-CSF stimulation. HDCT consists of a combination of carboplatin, etoposide and ifosfamide or cyclophosphamide. After HDCT, haematologic monitoring and maximal supportive care are essential. It is therefore recommended that HDCT only be administered at specialized centres.

Nephrotoxicity after high-dose carboplatin, etoposide and ifosfamide in germ-cell tumors: incidence and implications for hematologic recovery and clinical outcome

High-dose carboplatin, etoposide and ifosfamide (CEI) is an active chemotherapy regimen (HDCT) in solid tumors and lymphomas. In patients with previous exposure to cisplatin, its nephrotoxicity is dose-limiting. To determine the implications of nephrotoxicity on hematological recovery and clinical outcome, we analyzed 150 consecutive patients with germ cell tumors treated between August 1989 and September 1995 with carboplatin 1500-2000 mg/m2, etoposide 1200-2400 mg/m2, and ifosfamide 0-10 g/m2 followed by either BM or PBPC rescue. Five patients died (3%), three in the context of severe renal toxicity and early multiorgan failure. Overall, acute nephrotoxicity occurred in 43/150 (29%) patients, particularly at doses of carboplatin >1500 mg/m2. Hemodialysis was required in 12/150 (8%) patients, but could be discontinued until discharge in all except two survivors. Nephrotoxicity did not delay hematologic recovery when adjusted for the use of PBPC and hematopoietic growth factors by multivariate analysis, but resulted in higher transfusion requirements, more overall toxicities and a longer hospital stay. There were no differences in the response rates or survival in patients with or without nephrotoxicity. Acute nephrotoxicity is a frequent and clinically relevant complication of CEI in germ cell tumors. The acute side-effects from CEI are reversible in the majority of patients.

Subclassification of diffuse large B-cell lymphomas according to the Kiel classification: distinction of centroblastic and immunoblastic lymphomas is a significant prognostic risk factor

Among high-grade malignant non-Hodgkin's lymphomas the updated Kiel classification identifies three major B-cell entities: centroblastic (CB), B-immunoblastic (B-IB), and B-large cell anaplastic (Ki-1+) (now termed anaplastic large cell [CD30+], [B-ALC]). The clinical prognostic relevance of this distinction was evaluated in a randomized prospective treatment trial (COP-BLAM/IMVP-16 regimen randomly combined +/- radiotherapy in complete responders) conducted in adult (age 15 to 75) patients with Ann Arbor stage II-IV disease (n = 219) diagnosed by optimal histomorphology (Giemsa staining) and by immunohistochemistry. Overall survival was significantly better in CB lymphoma as compared to B-IB (P = .0002) or B-ALC (P = .046). Relapse-free survival was worse for B-IB (P = .0003) as compared to CB lymphomas. The prognostic differences between CB and B-IB were confirmed by multivariate analyses including the risk factors of the International Index. Overall survival was significantly determined by performance status (P = .0003), serum-LDH (P = .036), and B-IB histology subtype (P = .036). Relapse-free survival was influenced by age (P = .007) and histological subtype (P = .007). Thus, the diagnosis of the CB and B-IB lymphomas by the histological criteria of the Kiel classification was identified as an independent prognostic factor in diffuse large B-cell lymphomas.

Chronic lymphatic leukemias of T and NK cell type

T cell chronic lymphocytic/prolymphocytic leukemia (T-CLL/T-PLL) and large granular lymphocyte leukemia of T or NK cell type (T-LGL or NK-LGL leukemia) are chronic lymphoproliferative diseases derived from post-thymic immunocompetent lymphoid cells. T-PLL is morphologically characterized by a prominent central nucleolus in a medium-sized cell expressing a mature T cell immunophenotype. Clonal genetic changes involving chromosome 14 and T cell receptor gene rearrangements are characteristics of these diseases. They are usually progressive and there is no efficient treatment available. The classification of some cases presenting with a morphological picture similar to B-CLL, but with immunophenotypic and clinical features resembling T-PLL, as T-CLL is still controversial. The phenotypic profiles and the establishment of clonality are the hallmarks of defining T-LGL leukemia and NK-LGL leukemia. The CD3+/CD57+/CD56- immunophenotype and the clonal rearrangement of the T cell receptor genes characterize T-LGL leukemia, which presents clinically with a rather indolent course of disease, complicated by frequent infections secondary to neutropenia. NK-LGL leukemia cells express CD3-/CD56+/CD57-, but in most cases clonality cannot easily be established. Clinically the patient may either present with constitutional symptoms and suffer a short and aggressive course of disease or may have a more chronic disease similar to T-LGL leukemia. Therefore, it may be reasonable to subdivide NK-LGL proliferation into the more aggressive 'NK-LGL leukemia/lymphoma' and 'chronic NK cell lymphocytosis'.

Long-term survival of patients with recurrent or refractory germ cell tumors after high dose chemotherapy

BACKGROUND

The optimal treatment of patients with recurrent or refractory germ cell tumors is still a debated topic. High dose chemotherapy (HDCT) with autologous stem cell rescue (ASCR) might be promising for intensification of first or subsequent salvage treatment. However, the long-term results of this approach remain largely unknown.

METHODS

Between August 1989 and September 1992, 74 patients with recurrent and/or refractory germ cell tumors were treated in a Phase I/II trial with HDCT consisting of carboplatin (1500-2000 mg/m2), etoposide (1200-2400 mg/m2), and ifosfamide (0-10 g/m2). In September 1995 all patients were reevaluated to determine overall response, late toxicities, and survival.

RESULTS

Two patients died from treatment-related toxicity shortly after HDCT, and 47 had recurrence or progression of disease after a median of 3 months (range, 1-44 months). Of these latter patients, three were living continuously disease free at the conclusion of this study after a second HDCT regimen, salvage surgery, or chronic oral etoposide treatment. The results were an overall survival of 38% (95% confidence interval, 27-50%) and a failure free survival of 31% (95% confidence interval, 21-43%) at 5 years. There were no long-term survivors among patients whose disease progressed while they were receiving conventional doses of cisplatin before HDCT. Late toxicities consisted mainly or renal impairment (in 21% of patients), paresthesias (in 29%), and ototoxicity (in 18%).

CONCLUSIONS

HDCT can be curative for patients with germ cell tumors who do not become disease free after conventional dose chemotherapy but respond to this treatment.

Peripheral blood progenitor cell collection during hematopoietic recovery following autologous blood progenitor cell transplantation

BACKGROUND AND OBJECTIVES

Peripheral blood progenitor cells (PBPC) are increasingly used for autologous transplantation after high-dose radio/chemotherapy in patients suffering from cancer. PBPC are usually collected after mobilization with conventional-dose chemotherapy plus growth factor. However, it is conceivable to perform leukapheresis for the second autograft during recovery of hematopoiesis after the first course of HDCT/ABPCT.

MATERIALS AND METHODS

We treated two patients this way. In the first, with germ cell cancer, six 12-liter leukaphereses yielded 1.8 x 10(6) CD34+ cells/kg after mobilization with cis-platinum, etoposide and ifosfamide (PEI) plus granulocyte colony-stimulating factor (G-CSF). The second patient, with relapsed Hodgkin's disease, underwent PBPC collection after treatment with dexamethasone, carmustine, etoposide, cytarabine and melphalan (DexaBEAM) plus G-CSF. Due to excellent mobilization, 8.5 x 10(6) CD34+ cells/kg were collected by one 12-liter leukapheresis. Both patients then underwent PBPC collection during hematopoietic recovery following HDCT and ABPCT.

RESULTS

In patient 1, following HDCT and ABPCT, three 12-liter aphereses resulted in 0.7 x 10(6) CD34+ cells/kg. In patient 2, also after HDCT and ABPCT, a second autograft with 3.2 x 10(6) CD34+ cells/kg was harvested by a single 10-liter apheresis. No adverse effects were seen in either patient during apheresis following ABPCT. To our knowledge this is the first report dealing with PBCT collection during hematopoietic recovery following HDCT and ABPCT.

CONCLUSIONS

(1) PBPC harvesting is feasible and well tolerated in this setting. (2) In appropriate patients with efficient PBPC mobilization after conventional-dose chemotherapy, a further PBPC autograft can be collected during recovery of hematopoiesis after ABPCT, serving as a rescue for a second course of HDCT.

Splenic irradiation before bone marrow transplantation for chronic myeloid leukaemia. Chronic Leukaemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

A total of 229 patients with chronic myeloid leukaemia (CML) in chronic phase were randomized between 1986 and 1990 to receive or not receive additional splenic irradiation as part of their conditioning prior to bone marrow transplantation (BMT). Both groups, 115 patients with and 114 patients without splenic irradiation, were very similar regarding distribution of age, sex, donor/recipient sex combination, conditioning, graft-versus-host disease (GvHD) prevention method and blood counts at diagnosis or prior to transplant. 135 patients (59%) are alive as of October 1995 with a minimum follow-up of 5 years. 52 patients have relapsed (23%), 26 patients in the irradiated, 26 patients in the non-irradiated group (n.s.) with a relapse incidence at 6 years of 28%. The main risk factor for relapse was T-cell depletion as the method for GvHD prevention, and an elevated basophil count in the peripheral blood prior to transplant. Relapse incidence between patients with or without splenic irradiation was no different in patients at high risk for relapse, e.g. patients transplanted with T-cell-depleted marrows (P = n.s.) and in patients with low risk for relapse, e.g. patients transplanted with non-T-cell-depleted transplants and basophil counts < 3% prior to transplant (P = n.s.). However, relapse incidence differed significantly in patients with non-T-cell-depleted transplants and high basophil counts (> 3% basophils in peripheral blood). In this patient group, relapse incidence was 11% at 6 years with splenic irradiation but 32% in the non-irradiated group (P = 0.05). Transplant-related mortality was similar whether patients received splenic irradiation or not. This study suggests an advantage in splenic irradiation prior to transplantation for CML in this subgroup of patients and illustrates the need for tailored therapy.

High-dose chemotherapy as salvage treatment in germ cell tumors: a multivariate analysis of prognostic variables

PURPOSE

To identify prognostic variables for response and survival in male patients with relapsed or refractory germ cell tumors treated with high-dose chemotherapy (HDCT) and hematopoietic progenitor cell support.

PATIENTS AND METHODS

Three hundred ten patients treated with HDCT at four centers in the United States and Europe were retrospectively evaluated. Univariate and multivariate analysis of patient, disease, and treatment characteristics were used for comparisons of response rates and failure-free survival (FFS).

RESULTS

The actuarial FFS rate was 32% at 1, 30% at 2, and 29% at 3 years. Multivariate analysis identified progressive disease before HDCT, mediastinal nonseminomatous primary tumor, refractory or absolute refractory disease to conventional-dose cisplatin, and human chorionic gonadotropin (HCG) levels greater than 1,000 U/L before HDCT as independent adverse prognostic variables for FFS after HDCT. These variables were used to identify patients with good, intermediate, and poor prognoses. In the good-risk category, the predicted FFS rate at 2 years was 51%, compared with 27% and 5% in the intermediate-risk and poor-risk categories (P < .001). The increased risk for treatment failure was due to both a significantly lower rate of favorable responses and a significantly higher rate of relapses. Within the prognostic categories, the particular HDCT regimen or higher dosages of carboplatin or etoposide did not have a significant influence on treatment outcome.

CONCLUSION

Prognostic variables for treatment response after HDCT can be identified. The proposed prognostic model might help to optimize the use of HDCT in germ cell tumors and warrants validation in future trials.

Preliminary results of stem cell mobilization in chronic myeloid leukemia with a moderate intensity chemotherapy regimen and G-CSF or G-CSF plus IL-3

Mobilization of Philadelphia chromosome (Ph) negative peripheral blood stem cells has been reported subsequent to intensive chemotherapy. We asked whether peripheral blood stem cells can be harvested subsequent to a less toxic chemotherapy regimen. Patients were treated with idarubicin 12 mg/m2 on day 1 and 2 and ara-C 100 mg/m2 days 1-5 and 5 or 10 micrograms/m2 G-CSF. In case of insufficient yield chemotherapy was repeated using IL-3 and G-CSF for mobilization of stem cells. Fourteen patients received 18 cycles of chemotherapy. The majority of patients were in late chronic phase and treated after secondary (interferon-alpha) IFN-alpha resistance. sufficient numbers of peripheral blood stem cells were harvested in 11 out of 14 patients. Although mixed Ph positive/Ph negative leukaphereses were harvested in the majority of patients, in no case were sufficient numbers of purely Ph negative progenitor cells for transplantation obtained. No toxic deaths were observed during the aplasia and the toxicity was acceptable. These preliminary results demonstrate that this procedure can be safely applied in patients with chronic phase CML and allows the harvesting of sufficient numbers of peripheral blood stem cells. The efficacy of this regimen for the mobilization of Ph negative cells should be further explored in patients at an earlier stage of the disease.

Impact of preleukapheresis cell counts on collection results and correlation of progenitor-cell dose with engraftment after high-dose chemotherapy in patients with germ cell cancer

PURPOSE

To identify predictive factors for a good leukapheresis yield and to determine peripheral-blood progenitor cell (PBPC) dose requirements for rapid hematopoietic engraftment.

PATIENTS AND METHODS

Seventy-one patients with germ cell cancer (GCC) underwent PBPC harvest for autologous transplantation following high-dose therapy. Aphereses were performed after chemotherapy during granulocyte colony-stimulating factor (G-CSF) administration.

RESULTS

A median of two aphereses (range, two to five) resulted in 4.6 x 10(8) mononuclear cells (MNC)/kg, 15.7 x 10(4) colony-stimulating units granulocyte-macrophage (CFU-GM)/kg, and 6.0 x 10(6) CD34+ cells/kg. Peripheral blood MNC count correlated significantly with number of harvested CD34+ cells per kilogram (r = .49; P < .0001) and with CFU-GM count per kilogram (r = .35; P < .002). Circulating CD34+ cells from peripheral blood gave the best correlations to collected CD34+ cells per kilogram (r = .92; P < .0001), as well as to harvested CFU-GM per kilogram (r = .48; P < .0001). A preleukapheresis number of CD34+ cells greater than 4 x 10(4)/mL was highly predictive for a PBPC collection yield that contained more than 2.5 x 10(6) CD34+ cells/kg harvested by a single leukapheresis. After autologous transplantation, 41 patients were assessable for hematopoietic engraftment. They engrafted in a median time of 9 days (range, 7 to 18) to a WBC count greater than 1.0 x 10(9)/L, 10 days (range, 7 to 18) to an absolute neutrophil count (ANC) greater than 0.5 x 10(9)/L, and 11 days (range, 7 to 62) to a platelet (PLT) count greater than 20 x 10(9)/L. Good correlations were seen between reinfused CD34+ cell count and recovery of WBC count, ANC, and PLT count, with r values of .65 (P < .001), .65 (P < .001), and .45 (P < .03), respectively. Patients reinfused with a PBPC dose greater than 2.5 x 10(6) CD34+ cells/kg recovered hematopoiesis in a significantly shorter time than patients who received less than 2.5 x 10(6) CD34+ cells/kg.

CONCLUSION

Rapid hematopoietic engraftment can be achieved by a PBPC dose of greater than 2.5 x 10(6) CD34+ cells/kg. When circulating preleukapheresis CD34+ cell counts are greater than 4 x 10(4)/mL, a PBPC autograft that contains more than 2.5 x 10(6) CD34+ cells/kg can be collected by a single leukapheresis.

Acute myeloid and T-cell acute lymphoblastic leukaemia with aberrant antigen expression exhibit similar TCRdelta gene rearrangements

TCR delta gene recombination patterns were analysed by Southern blot, polymerase chain reaction and nucleotide sequencing in acute myeloid leukaemias, with coexpression of lymphoid antigens (Ly+ AML, n=10) as well as in early T-cell acute lymphoblastic leukaemias with (My+ T-ALL, n=10) and without coexpression of myeloid antigens (My(-) T-ALL, n=9). These 29 acute leukaemias exhibiting TCR delta gene rearrangements were selected from 66 Ly+ AML, 14 My+ T-ALL and 12 My(-) T-ALL cases. Similar recombination patterns, namely D delta 2J delta1 and V delta 1J delta1 gene rearrangements, were observed in Ly+ AML and My+T-ALL. In contrast to V delta2 D delta3 rearrangements in B-cell precursor ALL, these rearrangements require activation of a T-cell-specific TCR delta enhancer. Comparison of My+ T-ALL and Ly+ AML with My(-) T-ALL exhibited a higher incidence of incomplete D delta 2J delta1 rearrangements in My+ T-ALL and Ly+ AML. Since a D delta 2J delta1 rearrangement is an early event in TCR delta recombination, these leukaemias seem to be arrested at an earlier stage of differentiation. Similar patterns of TCR delta rearrangements in My+ T-ALL and Ly+ AML suggest existence of a common myeloid/T-lymphoid progenitor cell. Although weak or missing expression of terminal deoxynucleotidyl transferase (T delta T) was found in 7/10 Ly+ AML cases, no difference was observed in numbers of N-nucleotides inserted in junctional regions when comparing with 3/10 cases exhibiting TdT expression. Since TdT activity is necessary for N-nucleotide addition, this finding suggests down-regulation of T delta T expression after rearrangement took place in these Ly+ AML cases.