Genetically identical twin transplantation for chronic lymphocytic leukemia.

We identified 19 persons with B-cell chronic lymphocytic leukemia (CLL) who received genetically identical twin blood cell or bone marrow transplants after high-dose conditioning. Ten are alive (eight disease-free) with a median follow-up of 89 months (range, 31-171 months); 5-year relapse rate was 50% (95% confidence interval (CI), 26-73%). Estimated 5-year survival and disease-free survival were 61% (95% CI, 37-82%) and 45% (95% CI, 23-68%). In two of four patients tested at 12 and 21 months by polymerase chain reaction no evidence of residual CLL was detected post-transplant. In one recipient who relapsed at 6 years, molecular studies showed a different CLL clone from that detected pretransplant. This clone was subsequently identified in the donor suggesting transfer of occult leukemia at the time of transplant. Genetically identical twin transplants can result in long-term disease-free survival and molecular remissions, these data suggest the potential for CLL control in the absence of allogeneic graft-versus-leukemia effect. The case of leukemia transfer indicates the need for careful evaluation of donors prior to graft collection.

Protein-protein interaction using tryptophan analogues: novel spectroscopic probes for toxin-elongation factor-2 interactions.

Previously, we characterized the role of the three naturally occurring Trp residues (W-417, -466, and -558) in the catalytic mechanism of the toxin-enzyme produced by Pseudomonas aeruginosa [Beattie and Merrill (1999) J. Biol. Chem. 274, 15646-15654]. However, the use of intrinsic Trp fluorescence to study toxin-eEF-2 interaction is inherently limited since the spectral properties of the various Trp residues in both proteins cannot easily be distinguished. To facilitate the study of the protein-protein interaction by Trp fluorescence spectroscopy, the Trp residues in the catalytic domain of exotoxin A were replaced with the amino acid analogues 4-fluorotryptophan, 5-fluorotryptophan, 5-hydroxytryptophan, and 7-azatryptophan. The incorporation of analogues was achieved by using a tightly regulated promoter, pBAD, and expressing the protein in a Trp auxotrophic strain of Escherichia coli, BL21, in a minimal medium containing the appropriate tryptophan analogue. Quantitative spectral analysis of the analogue-containing proteins using the Decompose program indicated that we had achieved 87-100% incorporation efficiency depending on the Trp analogue being used. Electrospray mass spectrometry analysis verified that we had achieved nearly total replacement of the L-tryptophan residues within the catalytic domain of exotoxin A with the tryptophan analogues 5-fluorotryptophan and 4-fluorotryptophan. The analogue-substituted proteins showed a variation in their catalytic activities with k(cat) values ranging from 6-fold (4-fluorotryptophan) to 260-fold (5-hydroxytryptophan) lower than the natural enzyme, which was in agreement with previous data using site-directed mutagenesis [Beattie et al. (1996) Biochemistry 35, 15134-15142]. However, the analogue-incorporated enzymes did not show any significant change in their ability to bind NAD(+) as substrate, as determined from a fluorescence-binding assay. The spectral properties of the various analogue-incorporated proteins were evaluated and compared with those of the native protein. Furthermore, selective excitation of the 5-hydroxytryptophan-incorporated toxin was exploited to study its interaction with the elongation factor-2 substrate by fluorescence resonance energy transfer to an acceptor chromophore located on the elongation factor-2 protein. The binding between the toxin-enzyme and elongation factor-2 was shown to be independent of the NAD(+) substrate (983 +/- 63 nM) and showed a small dependence upon the ionic strength of the solution.

Collection of hematopoietic stem cells from patients with autoimmune diseases.

We reviewed data from 24 transplant centers in Asia, Australia, Europe, and North America to determine the outcomes of stem cell collection including methods used, cell yields, effects on disease activity, and complications in patients with autoimmune diseases. Twenty-one unprimed bone marrow harvests and 174 peripheral blood stem cell mobilizations were performed on 187 patients. Disease indications were multiple sclerosis (76 patients), rheumatoid arthritis (37 patients), scleroderma (26 patients), systemic lupus erythematosus (19 patients), juvenile chronic arthritis (13 patients), idiopathic autoimmune thrombocytopenia (8 patients), Behcet's disease (3 patients), undifferentiated vasculitis (3 patients), polychondritis (1 patient) and polymyositis (1 patient). Bone marrow harvests were used in the Peoples Republic of China and preferred worldwide for children. PBSC mobilization was the preferred technique for adult stem cell collection in America, Australia, and Europe. Methods of PBSC mobilization included G-CSF (5, 10, or 16 microg/kg/day) or cyclophosphamide (2 or 4 g/m2) with either G-CSF (5 or 10 microg/kg/day) or GM-CSF (5 microg/kg/day). Bone marrow harvests were without complications and did not affect disease activity. A combination of cyclophosphamide and G-CSF was more likely to ameliorate disease activity than G-CSF alone (P < 0.001). g-csf alone was more likely to cause disease exacerbation than the combination of cyclophosphamide and g-csf (P = 0.003). Three patients died as a result of cyclophosphamide-based stem cell collection (2.6% of patients mobilized with cyclophosphamide). When corrected for patient weight and apheresis volume, progenitor cell yields tended to vary by underlying disease, prior medication history and mobilization regimen. Trends in the approaches to, and results of, progenitor cell mobilization are suggested by this survey. While cytokine-based mobilization appears less toxic, it is more likely to result in disease reactivation. Optimization with regard to cell yields and safety are likely to be disease-specific and prospective disease-specific studies of mobilization procedures appear warranted.

Comparison of bicistronic retroviral vectors containing internal ribosome entry sites (IRES) using expression of human interleukin-12 (IL-12) as a readout.

BACKGROUND: Many gene therapy applications require the co-ordinated delivery of more than one reading frame. We wished to systematically compare IRES in the context of a retroviral vector to determine which was the most effective for protein production and viral titre. To do this we monitored expression of IL-12, as co-ordinated expression of both p35 and p40 subunits is required for production of the active heterodimer. METHODS: Retroviral vectors were constructed to express human IL-12 in which an IRES initiates translation of the p40 subunit, with the IRES optimally aligned to the initiation codon of p40. Vectors containing an IRES from either polio virus (PV), encephalomyocarditis virus (EMCV), foot and mouth disease virus (FMDV) or murine leukaemia virus (MLV) were compared with a vector expressing IL-12 as a single protein (Flexi-12; in which the two IL-12 subunits are linked by a peptide). RESULTS: All vectors produced high titre virus and directed synthesis of IL-12 in target cells. The bicistronic vectors containing the IRES from EMCV and PV were the most effective in infected 3T3 cells, producing up to 40 ng IL-12/10(6) cells/48 h, similar to the 50 ng IL-12/10(6) cells/48 h obtained with Flexi-12. The IRES from PV was the most efficient in human melanoma cells. CONCLUSIONS: Bicistronic retroviral vectors have been constructed that effectively transduce target cells and produce high levels of protein. Target cell specificity of IRES function was observed. The combination of Flexi-12 and the IRES from PV will be useful in the generation of vectors expressing IL-12 with a second protein such as IL-2 for transduction of melanoma cells.

An enzyme-linked immunosorbent assay for the association of the catalytic domain of diphthamide-specific ribosyltransferases to eukaryotic elongation factor-2.

The X-ray structure of the catalytic domain of Pseudomonas aeruginosa exotoxin A (PE24) has recently been solved to high resolution, facilitating studies on the interaction of PE24 with its target substrate, eukaryotic elongation factor-2 (eEF-2). PE24 exhibits mono-ADP-ribosyltransferase (ADPRT) activity in a mechanism that has been proposed to feature a nucleophilic attack by the diphthamide residue (nucleophile) of eEF-2 on the C-1 of the nicotinamide ribose of NAD(+). The interaction of wheat germ eEF-2 with PE24 was studied by employing an enzyme-linked immunosorbent assay (ELISA), devised to assess protein-protein interactions. It was shown that the proteins associate with each other only in the presence of the enzyme's nucleotide substrate, NAD(+), and exhibit a dose-dependent association that is saturable. The apparent dissociation constant (K(d)) for this protein-protein interaction is 50 nM and is salt-dependent. The association is maximal at low ionic strength and is progressively weaker at higher salt concentrations, which corroborates previous findings on the salt dependence of ADPRT activity for this toxin. This finding suggests that the sensitivity of ADPRT activity toward high salt resides in the interaction between the catalytic domain of the toxin and eEF-2. A major product of the glycohydrolase activity of PE24, nicotinamide, inhibits the binding between PE24 and eEF-2 with an ID(50) of 20 microM. The naturally occurring, noncatalytic mutant of PE24, H426Y, did not bind eEF-2 in the ELISA, verifying that His 426 is located at the center of the eEF-2 binding site within ETA.

Identification of a chameleon-like pH-sensitive segment within the colicin E1 channel domain that may serve as the pH-activated trigger for membrane bilayer association.

In vitro, the channel-forming domain of colicin E1 requires activation by acidic pH (<4.5) or detergents. The activation of this domain to its insertion-competent state results in an increased ability of the protein to dock onto and to form channels in artificial membranes. Fluorescence methods were used to characterize the conformational changes occurring in a channel-forming peptide of colicin E1 in solution with pH. The 178-residue thermolytic fragment of colicin E1 contains three Trp residues, W-424, W-460, and W-495. In order to study the structural and dynamic requirements for activation of the C-terminal domain of colicin E1, single-Trp-containing peptides were prepared by site-directed mutagenesis. All of the mutant peptides displayed in vitro channel activity and cellular cytotoxicity similar to the those of wild-type peptide. Two Trp residues, W-413 and W-424, exhibited pH-sensitive fluorescence parameters. Upon acidification (pH 6.0 --> 3.5), the fluorescence quantum yield of W-413 and W-424 increased 50% and 80%, respectively, indicating a significant change in the local environment of the peptide segment containing these two Trp residues. The fluorescence decay of W-413 and W-424 was best fit by three fluorescence decay components, two of which were sensitive to pH. However, only small changes in spectral shape and position were observed for W-424 fluorescence, whereas there were larger changes in these fluorescence parameters for W-413. The quantum yields for the Trp residues in the seven other single-Trp mutant peptides and the wild-type peptide were distinct but only slightly affected by changes in pH. Time-resolved fluorescence measurements showed that W-460, -484, and -495 each had two fluorescence decay components with similar decay times, with one component dominating the fluorescence decay behavior. Furthermore, the individual fluorescence decay times for all the single-Trp peptides, except for W-413 and W-424, were insensitive to pH changes. At pH 3.5, the fluorescence of the wild-type peptide was fit by three decay time components, with the two longer decay times being quite different from the fluorescence decay times of the single-Trp mutant proteins (W-424, -460, and -495, the naturally occurring Trp residues). In contrast, at pH 6.0, the wild-type peptide showed double-exponential decay kinetics. Time-resolved fluorescence anisotropy decay measurements of the three single-Trp mutant proteins, containing a naturally occurring Trp residue, suggest that local segmental motion of the peptide as reported by each of the three tryptophans is highly restricted and largely insensitive to changes in pH. On the other hand, the anisotropy decay profiles of the wild-type protein were consistent with energy transfer occurring between Trp residues, likely between W-460 and W-495. These steady-state and time-resolved fluorescence results show that W-413 and W-424 report conformational changes which may be associated with the insertion-competent state and reside on the protein segment(s) which form the pH-activated trigger of the channel peptide.

Allogeneic bone marrow transplantation for acute leukemia in patients over the age of 40 years. Acute Leukemia Working Party of the European Group for Bone Marrow Transplantation (EBMT).

Extension of allogeneic transplants to older patients has been limited by a high risk of transplant-related death and graft-versus-host disease. To evaluate the feasibility in older patients, a retrospective analysis of the procedure was performed for first remission acute leukemia in 192 patients aged over 40 years and compared with a group of 1119 recipients aged from 16 to 40 years reported to the EBMT from 1986 to 1992. Patient-, disease-, and treatment-related variables were compared between the two age groups using the chi2 statistical method for categorical variables. Variables differing significantly or recognized as potential prognostic factors were included in a multivariate analysis. Leukemia-free survival and relapse were comparable among the age groups in the two types of leukemias. Incidence of graft-versus-host disease was higher in the older group of ALL patients. Older patients with AML in first remission had a higher treatment-related mortality incidence, with no influence on survival. A pair-matched analysis of AML patients did not show any statistical difference in the probability of LFS, RI, TRM, and survival for the two age cohorts of patients. These results suggest that BMT should be considered for patients over 40 years of age.

Investigation into the catalytic role for the tryptophan residues within domain III of Pseudomonas aeruginosa exotoxin A.

The role of the tryptophan residues in the substrate-binding and catalytic mechanism of an enzymatically active C-terminal fragment of Pseudomonas aeruginosa exotoxin A was studied by individually or jointly replacing these residues with phenylalanine. Substitution of W-466 decreased the ADP-ribosyltransferase and NAD(+)-glycohydrolase activities by 20- and 3-fold, respectively. In contrast, substitution of W-417 or W-558 with phenylalanine both resulted in a 3-fold decrease in ADP-ribosyltransferase activity with, however, only a decrease by 40% and 70% in NAD(+)-glycohydrolase activity, respectively. Simultaneous replacement of W-466 and W-558 resulted in a 200-fold decrease in ADP-ribosyltransferase and an 6-fold decrease in NAD(+)-glycohydrolase activities, suggesting that W-466 may play a minor role in the transfer of ADP-ribose to the eEF-2 protein. Chemical modification of the tryptophan residues in the wild-type toxin fragment by N-bromosuccinimide revealed the presence of a single residue important for enzymatic activity, W-466, with a minor contribution from W-558. Additionally, tryptophan residues, W-305 and W-417, were refractory to oxidation by N-bromosuccinimide, which likely indicated the buried nature of these residues within the protein structure. Titration of the wild-type toxin fragment with NAD+ resulted in the quenching of the intrinsic tryptophan fluorescence to 58% of the initial value. Titration of the various single and a double tryptophan replacement mutant protein(s) indicated that W-558 and W-466 are responsible for the substrate-induced fluorescence quenching, with the former being responsible for the largest fraction of the observed quenching in the wild-type toxin. Consequently, a molecular mechanism is proposed for the substrate-induced fluorescence quenching of both W-466 and W-558. Furthermore, molecular modeling of the recent crystal structures for both exotoxin A (domain III fragment) and diphtheria toxin, combined with a variety of previous results, has led to the proposal for a catalytic mechanism for the ADP-ribosyltransferase reaction. This mechanism features a SN1 attack (instead of the previously purported SN2 mechanism) by the diphthamide residue (nucleophile) of eukaryotic elongation factor 2 on the C-1 of the nicotinamide ribose of NAD+, which results in an inversion of configuration likely due to steric constraints within the NAD(+)-toxin-elongation factor 2 complex.

Relapse of acute promyelocytic leukemia follows serial negative RT-PCR assays: a cautionary tale.

Six patients with acute promyelocytic leukaemia (APL) and t(15;17) were investigated by cytogenetics and by reverse transcriptase polymerase chain reaction (RT-PCR) for the fusion transcript PML-RARA. The clone was detected in remission following all-trans retinoic acid and chemotherapy by cytogenetics and/or by RT-PCR up to 2 months from diagnosis. Thereafter the PML-RARA transcript was not seen in 20/21 first remission samples in five cases studied. Remission was maintained in two patients, one following bone marrow transplantation (BMT). Despite serial negative RT-PCR results, PML-RARA reemerged at or prior to relapse following BMT in the remaining three cases. Frequent molecular monitoring and caution in the interpretation of negative RT-PCR results are indicated in APL.

Immunisations after bone marrow transplantation: results of a European survey and recommendations from the infectious diseases working party of the European Group for Blood and Marrow Transplantation.

Increased numbers of recipients of BMTs and autologous BMTs are becoming long-term survivors. Existing data support that loss of protective immunity to agents such as tetanus and poliovirus is common in patients who received BMTs and autologous BMTs. Thus, a reimmunisation programme is needed to ensure immunity. A questionnaire concerning immunisation practices was sent to EBMT member centres. The immunisation practices varied extensively in the 59 responding BMT and 48 responding autologous BMT centres. Sixty five per cent of responding centres routinely immunise patients who received allogeneic BMTs whereas 37% were routinely immunising recipients of autologous BMTs. Tetanus toxoid and inactivated poliovirus vaccine were the most frequently used vaccines in both BMT and autologous BMT centres. Immunisations of recipients of both BMTs and autologous BMTs with tetanus toxoid, diphtheria toxoid, inactivated poliovirus vaccine and influenza vaccine are recommended. Other vaccines, and in particular live attenuated vaccines, may be considered on an individual basis.

Prognostic factors in autologous stem cell transplantation for multiple myeloma: an EBMT Registry Study. European Group for Bone Marrow Transplantation.

Autologous bone marrow- and blood progenitor cell transplantation was performed in 130 patients with multiple myeloma in 16 European centers between 1986 and 1993. At the time of follow-up, 77 patients were alive and 53 were dead. Complete remission after transplantation was obtained in 47% of all patients. The actuarial survival at 65 months was 28%. The median duration of relapse-free survival among patients who were in complete remission after transplantation was 29 months. The following factors were predictive for longer survival and freedom of progression in a univariate analysis: Male sex, age less than 45 years, a low serum-beta-2-microglobulin value at diagnosis, prior administration of only one treatment regimen, response on conventional chemotherapy immediately pretransplant and the use of a preparative regimen including melphalan. The last factor, in addition to stage I disease at diagnosis, male sex and responsive disease immediately pretransplant, were also demonstrated as independent predictive variables for longer survival in a multivariate analysis. Progression-free survival was significantly better for patients who were in complete remission after transplantation, as compared to those with persisting signs of disease. We conclude that high-dose chemo-radiotherapy with autologous stem cell transplantation can induce long-term responses, primarily in younger, male patients with chemotherapy-responsive early disease. High-dose melphalan, as single drug or in combination, appeared to be superior to other regimens. The chance of being persistently disease-free seemed to be greatest for patients being in complete remission already before the transplantation.

European survey of bone marrow transplantation in acute promyelocytic leukemia (M3). Working Party on Acute Leukemia of the European Cooperative Group for Bone Marrow Transplantation (EMBT).

Acute promyelocytic leukemia (M3) is a distinct subtype of AML considered to have better response to chemotherapy and a higher cure rate than other subtypes. We analyzed the outcome for 362 M3 patients transplanted in Europe from November 1979 to December 1992 and reported to the acute leukemia registry of the European Cooperative Group for Bone Marrow Transplantation (EMBT). Of these 362 patients, 187 received an autograft, 129 in first remission (CR1) and 58 in second remission (CR2), and 175 an allograft, 142 in CR1 and 33 in CR2. Patients autografted in CR1 had at 7 years a leukemia-free survival (LFS) of 48 +/- 5%, a relapse rate (RR) of 41 +/- 5% and a probability of transplant-related mortality (TRM) of 18 +/- 6%. Patients allografted in CR1 had a LFS of 42 +/- 6%, a RR of 28 +/- 5% and a TRM probability of 42 +/- 8%. For patients transplanted in CR2, the respective figures after auto and allotransplantation were: LFS: 31 +/- 7% and 22 +/- 8%, RR: 54 +/- 8% and 64 +/- 11%, TRM: 23 +/- 9% and 40 +/- 9%. These data, which do not permit comparison between autologous and allogeneic BMT, indicate that roughly 45% of M3 patients achieving CR1 may be cured by a marrow transplant. Since the recent use of transretinoic acid-containing induction regimens has increased early control for patients with AML M3, it will be important to find out how these results affect outcome following allogeneic or autologous BMT.

Dose conversion from aminophylline to theophylline in preterm infants.

Twenty two preterm infants were prospectively evaluated to assess the need for dose adjustment when converting enteral and parenteral routes of methylxanthine administration.Serum theophylline concentrations remained unchanged in 18 infants after conversion from intravenous aminophylline to theophylline by mouth without dose reduction, as is currently recommended [corrected]. Intravenous aminophylline and theophylline by mouth may therefore be prescribed at equivalent doses, with a possible reduction in drug errors, and improved stability of serum concentrations.

Determination of the presence of Listeria monocytogenes in milk and dairy products: IDF collaborative study.

A collaborative study was conducted on the recovery of viable Listeria monocytogenes from milk and dairy products (Camembert cheese, Limburger cheese, skim milk powder, and ice cream). Test portions were homogenized with Listeria-selective liquid enrichment medium and cultured at 30 degrees C for 48 h. The enrichment culture was then subcultured onto a solid isolation medium at 37 degrees C for 48 h. Suspected Listeria colonies were identified by appropriate conventional morphological, physiological, and biochemical tests. Five kinds of dairy matrixes were spiked with L. monocytogenes at 2 levels: 12 and 120 colony forming units (cfu)/25 g. Each of the 18 collaborating laboratories analyzed 15 blind test portions from each matrix, comprising 5 replicates at each spiking level and 5 uninoculated controls, for a total of 1350 analyses. The specificity of the method was 100%; its sensitivity was 94-100% at the high spiking level and 89-98% at the low spiking level, except for Limburger cheese, which was only 68%. No specificity or sensitivity differences were observed between laboratories for all matrixes at the high spiking level and for all except Limburger cheese at the low spiking level. The calculated 50% detection limit for all products except Limburger cheese was 1.6 cfu/25 g; the 50% detection limit for Limburger cheese itself was 4.1 cfu/25 g. The method was adopted first action by AOAC INTERNATIONAL.

Neutrophilic eccrine hidradenitis with an unusual presentation.

Neutrophilic eccrine hidradenitis (NEH) is an eruption most commonly seen in patients undergoing chemotherapy, and is characterized histologically by a neutrophilic infiltrate around the eccrine coils, with associated necrosis of the sweat coils. The rash usually affects the trunk and extremities, and the morphology of the lesions is very variable. We describe a patient with neutrophilic eccrine hidradenitis who presented with symmetrical, erythematous, swollen ears, a manifestation of NEH which has not been previously reported.

A medium for the detection of Lancefield Group D cocci in skimmed milk powder by measurement of conductivity changes.

A selective medium for the detection of Lancefield Group D cocci in skimmed milk powder by conductivity measurements was developed and evaluated using the Bactometer M123 and Malthus 128H systems. This medium promoted large changes in conductance and capacitance. The calibration curve of detection times vs concentration of Lancefield Group D cocci showed a linear correlation coefficient of 0.93 and the method gave comparable results in both conductivity instruments. Naturally contaminated samples containing c. 10(3) cfu/g of Lancefield Group D cocci gave detection times within 16-18 h which was sufficiently rapid for the medium to be used for the routine screening of skimmed milk powder.

Multiple chromosome abnormalities in a drug resistant TdT positive B-cell leukemia.

A 17-year old caucasian male presented with B-cell acute leukemia which proved aggressive and refractory to treatment. Cytogenic investigation showed a single clone with a complex karyotype 49,XY,del(2)(p13),+4,del(4)(p11),-6,+i(6)(p),+7,+8, t(8;14), (q24;q32),del(17)(p11). This includes the Burkitt's translocation and a deletion at the site of the immunoglobulin kappa light chain gene. Clonal evolution included tetraploidy, duplication of the derived chromosomes and, terminally, trisomy 1q. Immunological investigation revealed a monoclonal population of B-cell blasts, expressing the kappa light chain, and with an extremely rare combination of SIg and TdT positivity. Immunoglobulin gene rearrangement confirmed monoclonalility. Tetraploidy of the clone and del(17)(p11) have been previously described only in a cell line or at end stage disease in B-ALL. It is suggested that the chromosomal abnormalities present at diagnosis were directly related to the refractory nature of this leukemia.