Liposomal daunorubicin: in vitro and in vivo efficacy in multiple myeloma

Liposomal encapsulation of anthracyclines is a potential method of drug targeting, altering both the antitumour activity and side-effect profile of anthracyclines. Liposomal daunorubicin (daunoxome) shows both altered pharmacokinetics and a potential for reducing dose-limiting cardiotoxicity compared to conventional daunorubicin. Anthracyclines have a common role in the treatment of multiple myeloma, a prevalent and fatal haematological malignancy. Avoiding cumulative anthracycline toxicity in these patients is important. There is also a need for more effective relapse schedules given that many patients have chemosensitive disease at relapse. We have analysed daunoxome in vitro in myeloma cell lines using a thymidine-based cytotoxicity assay and show superior efficacy compared to a pegylated liposomal doxorubicin derivative. Subsequently we have treated seven relapsed myeloma patients with a regime consisting of oral CCNU 25-50 mg/m2 on day 1, 4 days of oral dexamethasone 10 mg/m2 and intravenous daunoxome (liposomal daunorubicin) given for 4 days (total 100 mg/m2). The main toxicity was myelosuppression but non-haematological toxicity was minimal and the regime was well tolerated. Four out of seven of these heavily pretreated patients responded. Together with the in vitro data on its cytotoxicity in myeloma and its favourable pharmacokinetic profile further studies of liposomal daunorubicin in myeloma would be warranted.

Modern molecular diagnostics and the management of haematological malignancies

The advent of molecular biological techniques has led to a radical improvement in the evaluation of haematological disorders and offers exciting future prospects. In particular it has led to the improved recognition of distinct clinicopathological entities defined by a combination of morphological, immunophenotypic and chromosomal features. Antibody-based techniques, namely immunophenotyping and immunocytochemical techniques, are essential to malignant haematological diagnosis. More novel is the diagnostic use of antibodies against novel fusion proteins, for example in AML, M3 and anaplastic lymphoma. PCR-based techniques allow the identification of genetic mutations and translocations including such common translocations as t(14;18), t(9;22), inv 16 and t(8;21). Fish-based techniques are greatly improving the ability to detect genetic abnormalities including those conditions with low cell proliferation and current research-based techniques include the combination of FISH with cell surface markers (FICTION), FIBRE FISH and Comparative Genomic Hybridization. Molecular techniques are essential in monitoring residual disease which is best illustrated in CML. The development of real-time automated PCR offers exciting prospects in this field. The increasing number of tests, the need for an integrated approach to diagnosis and the need for cost effectiveness indicate that such services should be provided by a specialized haematology laboratory.

Trisomy 12 is seen within a specific subtype of B-cell chronic lymphoproliferative disease affecting the peripheral blood/bone marrow and co-segregates with elevated expression of CD11a

In order to delineate the specific morphological and immunophenotypic features of B-cell lymphoproliferative disorders associated with trisomy 12, 172 sequential unselected cases of CD19+CD5+ B-cell disorders, primarily affecting the peripheral blood and bone marrow, were studied. Trisomy 12 was found in 24 cases (13.9%), with all cases morphologically classified as either CLL-PL or CLL-mixed by FAB criteria. Trisomy 12 was not found in any cases of typical CLL. Trisomy 12 cases demonstrated a significant higher expression of CD11a (P<0.0001) and CD20 (P<0.0006) when compared to cases with the equivalent morphology and immunophenotype, but without the chromosomal abnormality. Trisomy 12 cases also demonstrated a higher frequency of FMC7, CD38 expression and moderate to strong surface immunoglobulin staining. However, no correlation was detected between the percentages of trisomy 12 cells and cells expressing CD11a, CD38, FMC7 or sIg mean fluorescent intensity. Cells from trisomy 12 positive cases were sorted according to their CD11a expression using fluorescent activated cell sorting. There was a significant increase in the percentage of trisomy 12 cells within the CD11a+ sorted fraction compared to the unsorted population (P < 0.05), implying that trisomy 12 is associated with increased expression of CD11a. With the highly specific morphological and immunophenotypic features demonstrated by trisomy 12 cases in this study, it is highly likely that these cases constitute a specific group of B-cell lymphoproliferative disorders.

The development of haematopathology laboratories: a possible model for other pathology services

The diagnosis of haematological malignancies has undergone major conceptual changes in the past decade. Accurate diagnosis now depends on a combination of morphological examination, cell marker studies, and molecular biological techniques. Specialist haematopathology diagnostic services are best provided in an integrated laboratory, able to carry out the full range of techniques and staffed by pathologists and scientists with expertise in the investigation of leukaemia and lymphoma.

Autologous stem cell transplantation in chronic myeloid leukaemia using Philadelphia chromosome negative blood progenitors mobilised with hydroxyurea and G-CSF

Autologous transplantation in CML has been a focus of interest over the last few years. Determining the indications, optimal timing and method for this procedure remains controversial. One approach has been the mobilisation of Philadelphia chromosome negative (Ph-) peripheral blood stem cells following high-dose chemotherapy as a method of purging the graft. We have described a mobilisation regimen of 7 days of hydroxyurea followed by G-CSF and have shown it to be substantially less toxic than other methods. We now report further experience with this technique in a total of 18 patients and the outcome of transplantation in seven patients using cells so-derived. Following mobilisation, approximately a third of patients had 100% Ph-collections and half had less than 50% Ph+ collections. All patients were 100% Ph+ prior to mobilisation. Six out of seven transplanted patients showed sustained engraftment and two of these patients became 18 and 34% Ph+ 3 months post-transplant. Five patients remain alive and well 13 to 25 months post-autograft. In conclusion, we have developed a well-tolerated regimen for Ph- PBSC mobilisation and have demonstrated that such cells are capable of sustained engraftment and of producing significant cytogenetic responses.

B-lymphocyte suppression in multiple myeloma is a reversible phenomenon specific to normal B-cell progenitors and plasma cell precursors

The reduced levels of normal immunoglobulin in patients with myeloma may be due to suppression of normal B-cell differentiation. However, reports on the numbers of B cells vary, with some finding decreases consistent with immunoparesis, and others reporting expansions of phenotypically aberrant cells. We have therefore assessed the phenotype and levels of B lymphocytes in patients at presentation (n = 23), in plateau or complete remission (PB n = 42, BM n = 18), and in relapse (PB n = 17, BM n = 14), in comparison to normal individuals (n = 10). Phenotypic analysis was performed using five-parameter flow cytometry, with CD14 used to exclude monocytes where necessary. We found no evidence of a phenotypically distinctive blood or marrow B-cell population in patients with myeloma, nor of an increase in the levels of any B-cell subset. Numbers of blood CD19+ 38+ normal plasma cell precursors were significantly reduced in presentation/relapse patients, but not in patients in plateau/remission. Total CD19+ cells were significantly reduced only in patients with circulating myeloma cells, detected by IgH-PCR. In the marrow, CD19+ B cells expressing CD5, CD10, CD34, CD38, CD45(low) and Syndecan-1 were significantly decreased at presentation/relapse, but not in patients in plateau/remission. The majority of these antigens are expressed by normal B-cell progenitors, indicating that myeloma also affects the early stages of B-cell development. The suppression of progenitor cells was not restricted to B-lymphoid differentiation, as total CD34+ cells were also significantly reduced in the marrow of myeloma patients at presentation. These results indicate that, if neoplastic B cells are present in myeloma, they are low in number and have a phenotype similar to their normal counterparts. Furthermore, there is a reversible suppression of CD19+ B lymphocytes that correlates inversely with disease stage, and specifically affects the early and late stages of normal B-cell differentiation.

Familial pancreatic lymphoma

Non-Hodgkin's lymphoma is not commonly a familial condition. This is believed to be the first two cases of primary pancreatic lymphoma within a single family. The two cases, a brother and sister, both presented in their 60s and were diagnosed histologically as having high grade B cell lymphoma affecting the pancreas, an uncommon primary site. Both responded well to treatment with chemotherapy and were in remission at the time of writing. On further investigation it was found that their mother also presented with a malignant lymphoma of cervical nodes 30 years earlier and subsequently died of the disease.

The rapid diagnosis of acute promyelocytic leukaemia using PML (5E10) monoclonal antibody

Acute promyelocytic leukaemia (APL) is characterized cytogenetically by t(15;17)(q22:q21) which results in the production of a PML/RAR alpha fusion protein. Detection of the translocation or the fusion gene product is required for objective diagnosis of APL. This can be accomplished by conventional cytogenetic methods, fluorescence in situ hybridization or RT-PCR. Such techniques are time consuming and not universally available. The intracellular distribution of the PML protein in promyelocytes is characteristically altered in APL and this can be detected by immunocytochemistry. We have assessed two immunocytochemical methods, immunofluorescence and alkaline phosphatase-anti-alkaline phosphatase staining (APAAP), with regard to sensitivity, specificity and rapidity of diagnosis. 85 patients with AML including 15 cases of APL were studied. Immunofluorescence PML detection was concordant with RT-PCR for t(15:17) in 14/15 (93.3%) cases with no false positives. The negative APL case in our series was a patient with a 5' PML breakpoint who did not express the reciprocal t(17;15) fusion product. APAAP was concordant in only 6/13 (46%) APL cases with one false positive. In conclusion, immunofluorescent localization of PML using 5E10 monoclonal antibody is a rapid, sensitive and specific diagnostic tool for APL.

Engraftment and molecular monitoring of CD34+ peripheral-blood stem-cell transplants for follicular lymphoma: a pilot study

PURPOSE

A pilot study to validate the use of CD34+ selection (Ceprate SC) of blood stem-cell collection in patients with advanced follicular lymphoma receiving myeloablative chemoradiotherapy.

PATIENTS AND METHODS

Seventeen patients were entered onto the protocol. Thirteen of 17 patients have undergone transplantation; the median age is 42.5 years (range, 33 to 51), seven of 13 are stage IVB, two stage IVA, three stage IIIB, and one stage IIB. All except two patients were treated after first or subsequent relapses after receiving cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy to achieve a good partial (six of 13) or complete (seven of 13) response before stem-cell mobilization with cyclophosphamide 3 g/m2 and filgrastim 300 microg once daily.

RESULTS

Eleven of 13 patients had a detectable t(14;18) by nested polymerase chain reaction (PCR). Median CD34+ count before selection was 2.9 x 10(6)/kg (range, 1.17 to 11.3) and after CD34+ selection was 1.54 x 10(6)/kg (range, 0.88 to 7.6) with a median CD34+ yield of 62.4% (range, 17% to 95%) and purity of 60% (range, 39.3% to 73%). Of the 11 patients known to have t(14;18), 10 had PCR-detectable contamination of stem-cell harvests that became PCR negative in six of the 10 after CD34+ selection. Engraftment was rapid with a median day to absolute neutrophil count (ANC) greater than 0.5 x 10(9)/L of 13 days (range, 11 to 21) and platelet count greater than 20 x 10(9)/L of 14 days (range, 10 to 44). With a median follow-up duration of 15 months, three patients have remained persistently PCR-positive, two of whom received PCR-positive stem cells. Two have relapsed. Of the seven patients who received PCR-negative stem cells, five have had no PCR-detectable disease in posttransplant bone marrow samples.

CONCLUSION

Longer follow-up duration is required to determine the significance of these findings, but we have confirmed the feasibility of CD34+ selected cells to deplete peripheral-blood stem cells of tumor cells from patients undergoing high-dose therapy for follicular lymphoma.

Comparison of fluorescent consensus IgH PCR and allele-specific oligonucleotide probing in the detection of minimal residual disease in childhood ALL

The sensitivity of detection of residual disease by two IgH PCR strategies, fluorescent framework 3 (Ffr3) and allele-specific oligonucleotide probing (ASOP), was compared in 57 'remission' BM samples obtained from 19 children with B-lineage acute lymphoblastic leukaemia (ALL). Oligonucleotide probing was more sensitive than FFr3 PCR in 10/16 cases, achieving a sensitivity of 0.01% or greater in 15/16 cases. Comparable sensitivities were obtained in the six remaining cases; the FFr3 PCR achieving a sensitivity of 0.1% or greater in 14/16 cases. 39/57 'remission' BM samples analysed showed no evidence of MRD by either technique although 18 were positive by ASOP and 14 positive by FFr3 PCR. The level of disease was estimated to be 0.01% or less in the four false negative samples.

Circulating plasma cells in multiple myeloma: characterization and correlation with disease stage

The aim of this study was to develop a flow cytometric test to quantitate low levels of circulating myeloma plasma cells, and to determine the relationship of these cells with disease stage. Cells were characterized using five-parameter flow cytometric analysis with a panel of antibodies, and results were evaluated by comparison with fluorescent consensus-primer IgH-PCR. Bone marrow myeloma plasma cells, defined by high CD38 and Syndecan-1 expression, did not express CD10, 23, 30, 34 or 45RO, and demonstrated weak expression of CD37 and CD45. 65% of patients had CD19- 56+ plasma cells, 30% CD19- 56(low), and 5% CD19+ 56+, and these two antigens discriminated myeloma from normal plasma cells, which were all CD19+ 56(low). Peripheral blood myeloma plasma cells had the same composite phenotype, but expressed significantly lower levels of CD56 and Syndecan-1, and were detected in 75% (38/51) of patients at presentation, 92% (11/12) of patients in relapse, and 40% (4/10) of stem cell harvests. Circulating plasma cells were not detectable in patients in CR (n = 9) or normals (n = 10), at a sensitivity of up to 1 in 10,000 cells. There was good correlation between the flow cytometric test and IgH-PCR results: myeloma plasma cells were detectable by flow cytometry in all PCR positive samples, and samples with no detectable myeloma plasma cells were PCR negative. Absolute numbers decreased in patients responding to treatment, remained elevated in patients with refractory disease, and increased in patients undergoing relapse. We conclude that flow cytometry can provide an effective aternative to IgH-PCR that will allow quantitative assessment of low levels of residual disease.

Detection and quantitation of the CBFbeta/MYH11 transcripts associated with the inv(16) in presentation and follow-up samples from patients with AML

We have developed a competitor-based RT-PCR technique which will detect and quantitate the CBFbeta/MYH11 transcripts associated with inv(16)(q22;p13) and have used it to study presentation and follow-up samples of acute myeloid leukaemia (AML). The levels of the leukaemia-specific transcripts are expressed as a ratio to a ubiquitously expressed mRNA species (Abl) which controls for RNA degradation. This technique has been applied to 75 consecutive patients presenting with either de novo AML or tMDS; 6/75 patients analysed were positive for the inv(16), all were confirmed by conventional cytogenetics. The inv(16) has a strong association with M4Eo, but we found only 2/6-positive patients to have this diagnosis (two patients with M2, one patient M1 and one patient had MDS). At presentation the levels of CBFbeta/MYH11 transcripts were 0.1-10/Abl transcript (mean 3.3/Abl transcript). Seventeen follow-up samples were available on 5/6 of these patients, and on two further patients in whom stored material was available. Following the first cycle of chemotherapy the level of transcripts was at least 10(-2) lower (0.1-10 x 10(-2)/abl transcript) than their presentation sample. Subsequent samples on these patients when in remission gave transcript levels in the range (1.0 x 10(-4) - 2 x 10(-3)/abl transcript), and three long-term follow-up samples were negative. We have developed a quantitative test which opens the possibility of predicting relapse by detecting changes in the numbers of leukaemia-specific transcripts.

p53 gene mutations in multiple myeloma

AIM

To assess whether p53 gene mutation is important in the pathogenesis and progression of multiple myeloma.

METHODS

Thirty eight DNA samples (derived predominantly from bone marrow) obtained from 31 patients with multiple myeloma were examined for mutations in p53 exons 5-9 by polymerase chain reaction single strand conformation polymorphism. Twenty three samples were analysed at the time of diagnosis (one patient had plasma cell leukaemia), three in plateau phase, and 12 at relapse (one plasma cell leukaemia and one extramedullary relapse).

RESULTS

One p53 mutation was detected in this group of patients (3.2%). This was seen in the diagnostic bone marrow sample of a 35 year old man with stage IIA disease and occurred in exon 6 as a result of a silent A to G transition at codon 213 (CGA-->CGG), a polymorphism that has been reported in about 3% of breast and lung tumours.

CONCLUSIONS

p53 gene mutations are rare events in multiple myeloma and would seem to be of limited value as a prognostic factor.

Supraomohyoid neck dissection

BACKGROUND

Supraomohyoid neck dissection (SOHND) has assumed increasing importance as a staging lymphadenectomy in patients with N(o) oral and oropharyngeal squamous cell carcinoma (SCC), as well as a potentially curative procedure in selected patients with limited metastatic disease in the neck.

METHODS

Retrospective chart review of 287 patients who had a total of 320 SOHND for SCC between 1986 and 1993 as a follow-up to an earlier report that covered our experience between 1980 and 1985. After excluding 24 patients who also had local recurrence, or a new primary, the remaining 296 SOHND were assessed for the effectiveness of tumor control in the neck.

RESULTS

Of 248 elective SOHND, clinically negative nodes proved histologically positive in 60 patients (25%), only 4 of whom failed in the neck (7%). A total of 48 patients (16%) had a therapeutic SOHND for limited N+ disease, confirmed pathologically in 31, with neck recurrence documented in 2 (6%). Nodes proved negative histologically in 205 patients, 10 of whom failed in the neck (5%). Nine of the 16 patients with neck recurrence had received postoperative radiation therapy and 9 recurred within the field of the SOHND.

CONCLUSIONS

SOHND is a reliable staging procedure in patients with N(o) oral or oropharyngeal SCC. Therapeutic SOHND, in conjunction with postoperative radiation therapy, was highly effective in controlling neck metastases in carefully selected patients with limited disease in the upper neck.

Quantitative PCR of the immunoglobulin heavy chain gene using genomic DNA

Techniques currently available enable the detection of clonal rearrangements of the immunoglobulin heavy chain gene using fluorescent PCR technology. It is possible to use this technique to analyse minimal residual disease throughout patient treatment: however, without the development of a quantitative assay, only the presence or absence of a clonal population can be determined. We describe here the development of a quantitative competitive PCR technique using genomic DNA which enables the rate of clearance of disease to be measured. In future, the ability to detect and also quantitate minimal residual disease may enhance the application of molecular investigations in the clinical management of patients.

Fluorescent polymerase chain reaction of a panel of CA repeats on chromosome 6 in the indolent phase of follicular centre cell lymphoma

Twenty-four cases of histologically defined follicle centre cell (FCC) lymphoma have been examined for allele imbalance at 19 microsatellite loci spanning the length of chromosome 6, including six markers within the major histocompatibility complex (MHC), using fluorescent polymerase chain reaction (PCR) to amplify microsatellites. Nineteen cases were observed in which imbalance of one or more markers on chromosome 6 had occurred (79%). The frequency of allele imbalance was significantly higher on 6p than 6q, and two regions of deletions, 6p24-25 and 6p21.3-23, were identified in which the loci showed a significantly high allele imbalance frequency.

The significance of B-cell clonality in gastric lymphoid infiltrates

The significance of the demonstration of a clonal B-cell population in gastric lymphoid infiltrates was investigated by analysis of immunoglobulin heavy chain (IgH) gene rearrangements using sensitive polymerase chain reactions, employing fluorescently labelled primers to target the FR3 and FR1 regions. Tissue blocks were studied showing different histological features (high-grade lymphoma, low-grade lymphoma, and chronic gastritis) from 12 gastrectomies for primary gastric lymphoma, together with blocks showing chronic gastritis from 13 cases of gastric adenocarcinoma and biopsies from 33 patients with active Helicobacter-associated chronic gastritis. Clonal IgH gene rearrangements were detected in lymphoma samples from eight of the gastrectomies for lymphoma (67 per cent). In four of these eight specimens, clonal rearrangements were also detectable in the samples showing only chronic gastritis. Three of 28 (11 per cent) informative biopsies showing active Helicobacter-associated chronic gastritis had detectable clonal populations. Clonal rearrangements were also demonstrated in two of eight (25 per cent) informative blocks showing chronic gastritis from eight gastrectomies for adenocarcinoma. It is concluded that the detection of a clonal population in a suspicious lymphoid infiltrate does not confirm the diagnosis of lymphoma, nor does the absence of such a population imply benignity.

Assessment of IgH PCR strategies in multiple myeloma

AIMS

To compare the ability of four commonly used PCR techniques to demonstrate clonal IgH rearrangements in multiple myeloma.

METHODS

Bone marrow samples (containing a minimum of 10% plasma cells) were obtained from 127 patients with confirmed multiple myeloma. Framework 3 (Fr3) PCR was performed in all cases and the Framework 1 (Fr1f) PCR, which utilises six VH family specific primers, in 98 cases. In addition, 44 cases were assessed by Fr3, Fr1f, Framework 2 (Fr2) and Framework 1 consensus (Fr1 con) PCR techniques. JH primer selection was also assessed such that each PCR strategy was performed twice in each of the 44 cases, using the JH consensus primer (JH con) alone and then repeated with an equimolar mixture of JH con, JH3 and JH6 (JH mix).

RESULTS

Clonal rearrangements were demonstrated in 71 (56%) of 127 cases with the Fr3 PCR and in 52 (53%) of 98 with the Fr1f PCR. However, by using both techniques it was possible to demonstrate clonal IgH rearrangements in 92 (75%) of 122 cases. Forty four cases were assessed by all four PCR techniques; in these cases the Fr3 and Fr1f PCRs demonstrated clonal rearrangements in 26 (59%) cases with a combined yield of 34 (77%). The Fr2 and Fr1 con PCR techniques had inferior pick up rates, demonstrating clonal rearrangements in 21 (48%) of 44 cases and a combined yield of 28 (63%). The Fr2 PCR did, however, demonstrate a clonal rearrangement in one case negative by both Fr3 and Fr1f. Two additional rearrangements were demonstrated by using JH mix; one became positive by Fr3, Fr1f and Fr2 and the other positive by Fr1f, Fr1 con and Fr2.

CONCLUSIONS

By utilising both the Fr3 and Fr1f PCR techniques it is possible to demonstrate definitive clonal rearrangements in the majority of patients with multiple myeloma. The Fr1 con and Fr2 PCR techniques have inferior pick up rates but may detect some additional rearrangements.

Mobilization of Philadelphia-negative peripheral blood mononuclear cells in chronic myeloid leukaemia using hydroxyurea and G-CSF (filgrastim)

A relatively simple and non-toxic out-patient-based regimen for the mobilization of Philadelphia-negative (Ph-ve) mononuclear cells in chronic myeloid leukaemia (CML) was evaluated in 10 patients, nine in stable chronic phase and one in accelerated phase. They received oral hydroxyurea at a mean dose of 3.5 g/m2 daily for 7 d, followed by 300 micrograms of G-CSF daily until the last day of harvesting. In the nine chronic-phase patients the mean number of days from the end of hydroxyurea to the commencement of harvesting was 14.5 (range 10-18). The patient in accelerated phase recovered and was harvested after 6 d. The mean number of aphereses performed was 3.4. Adequate numbers of stem cells were obtained in 9/10 patients judged by our usual criteria. Side-effects were mild in comparison to published intravenous schedules. No patients lost their hair. Five (50%) patients required admission with neutropenic fever which responded to antibiotics in all cases. Four (40%) patients developed a transient rash and four (40%) experienced mild oral mucostis. This level of toxicity enabled half of the patients to be treated entirely on an out-patient basis. The harvest products were analysed for cells belonging to the leukaemic clone by conventional cytogenetics, FISH and PCR. All were PCR positive. The mean Ph positivities by cytogenetics and FISH were comparable at 18.1% and 15% respectively. Half the patients had > 98% normal metaphases. We conclude that this approach is comparable in efficacy to published intravenous regimens and significantly less toxic. It can be safely used at diagnosis before interferon therapy commences.

Allele imbalance at tumour suppressor loci during the indolent phase of follicle centre cell lymphoma

We have examined 41 cases of follicle centre cell lymphoma with fluorescent PCR of microsatellite repeats closely linked to or within six tumour suppressor gene loci (APC, DCC, P53, RB1, WT1 and NM23). These probes are highly informative with heterozygousity rates in the range of 57%-90%. In addition we have used four loci from chromosome 6 (D6S260, TNFa, D6S281 and D6S262) as control loci which are unlikely to be involved in the pathogenesis of lymphoma. Of 369 informative PCR reactions allele imbalance was identified in 38 (10%) and this was seen in 23 of the 41 cases. Looking at individual loci allele imbalance was seen in APC(1) 11%, APC(2) 12%, P53(1) 5%, P53 (2) 7%, WT1 5%, RB1 13%, DCC 18% and NM23 0%. This frequency of change was no different from that seen at the control loci D6S260 16%, TNFa 20%, D6S281 4% and D6S262 9%. In the indolent phase of germinal centre cell lymphoma there is therefore quite a high rate of allele imbalance at all loci but this is no higher in those loci linked to tumour suppressor genes.

Peripheral blood stem cell transplantation in myeloma using CD34 selected cells

We have performed nine CD34 selection procedures on peripheral blood stem cells harvested from eight patients with myeloma using the Cellpro avidin-biotin immunoaffinity column (Ceprate). They all received CVAMP chemotherapy to maximum response prior to mobilisation. Six of the patients have been transplanted using these cells, one receiving successive autografts. Median absolute cell numbers processed and retrieved were: 31.1 x 10(9) pre-column, 2.07 x 10(8) in the final product and 30.4 x 10(9) in the column waste. Mean CD34 positivity in the product was 49% (range 18.4-98) with a median CD34+ yield of 31.4% (range 21-37.8). IgH PCR was performed and seven of the eight patients were amplifiable. Of these, two were positive in the pre-column product and both of these were successfully purged with a negative result in the final, post-column product. Patients were transplanted with a median of 2.0 x 10(6) CD34+ cells/kg (range 1.5-9.4) following conditioning with melphalan 200 mg/m2. The mean time to recovery of neutrophils to > 0.5 x 10(9)/l and platelets to > 20 x 10(9)/l was 16 and 17 days, respectively. At a mean follow-up of 9 months, four of the six patients transplanted are alive, three of them in complete remission and one in a clinically stable relapse. One has died of disease relapse and one of progressive neurological problems the aetiology of which was uncertain but there was no sign of progression of their myeloma. We conclude that PBSCT using CD34 selected cells is safe and practical in myeloma following remission induction with CVAMP chemotherapy.