Retroviral display of antibody fragments; interdomain spacing strongly influences vector infectivity.

Five different single-chain antibody fragments (scFv) against human cell-surface antigens were displayed on murine ecotropic retroviral vectors by fusing them to the Moloney SU envelope glycoprotein. The spacing between the scFv and the SU glycoprotein was varied by fusing the scFv to residue +7 or to residue +1 of Moloney SU and by inserting linker sequences of different lengths between the domains. All of the chimeric envelopes were efficiently incorporated into vector particles and could bind to human cells through their displayed antibody fragments, but did not infect them. The spacing between the scFvs and the SU glycoproteins had no significant effect on the efficiency of envelope expression or viral incorporation and did not affect the binding properties of the chimeric envelopes, nor did it influence the efficiency of targeted gene delivery to human cells by scFv-displaying vectors. However, on murine fibroblasts the infectivity of vectors incorporating the chimeric envelopes was strongly influenced by the length of the interdomain spacer. The titers were very low when the single-chain antibodies were fused through a tripeptide linker to SU residue +7 and were greatly enhanced (up to 10(5)-fold) when they were fused to SU residue +1 through a heptapeptide linker. These results point to the importance of steric interactions between the domains of chimeric envelope glycoproteins and may have implications for retroviral vector design for human gene therapy.

High-dose melphalan followed by autograft employing non-cryopreserved peripheral blood progenitor cells in children.

High-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) enables dose escalation in the treatment of childhood malignancies. Here we report our experience of using peripheral blood progenitor cells (PBPC) to restore haematopoiesis in five children using a simple cell mobilising regime and non-cryopreservation of the harvests. Cells were mobilised using cyclophosphamide and granulocyte colony stimulating factor. Each patient underwent only two leukaphereses, the product being stored before use at 4 degrees C. Successful autologous PBPC transplantation was achieved with melphalan conditioning chemotherapy and re-infusion of the total progenitor cell product. No colony stimulating factors were administered after transplantation. The median numbers of mononuclear cells collected per patient was 10.0 x 10(8)/kg (range 8.13-19.44) and CFU-GM 57.6 x 10(4)/kg (range 10.4-178.85). All patients subsequently engrafted with the median number of days to a neutrophil count > 0.5 x 10(9)/l being 11 (range 10-16), and to a platelet count > 50 x 10(9)/l being 14 (range 12-31). The median number of in-patient days was only 20 (range 19-30). The median demand for blood was 2 units (range 1-2), and platelets 4 units (range 2-28). Usage of systemic antimicrobials and intravenous feeding was also low. Using this simple strategy, collection and transplantation of autologous progenitor cells can be a straightforward procedure in children. It is possible that this could enable dose escalation in some poor prognosis paediatric tumours.

Technetium (99mTc)-labelled white cell scanning, 51Cr-EDTA and 14C-mannitol-labelled intestinal permeability studies: non-invasive methods of diagnosing acute intestinal graft-versus-host disease.

We describe a case of a 38-year-old female who presented with diarrhoea and abdominal pain 27 days after a second 'top-up' allogeneic marrow infusion for acute myeloid leukaemia (AML) in first remission. A clinical diagnosis of gut graft-versus-host disease (GVHD) was made. Technetium (99mTc)-labelled white cell scanning and intestinal permeability studies using 51Cr-EDTA and 14C-mannitol were undertaken to confirm the diagnosis. The 99mTc white cell scan showed extensive uptake in the small bowel and the urinary excretion of 51Cr-EDTA was increased, the results being consistent with intestinal inflammation and gut GVHD. 99mTc white cell scanning and intestinal permeability studies may assist in the diagnosis of gut GVHD and in assessing its extent and response to treatment.

Liquid storage of peripheral blood progenitor cells for transplantation.

Peripheral blood progenitor cells (PBPC) were mobilised by recombinant human G-CSF (rhG-CSF) and cyclophosphamide, harvested by apheresis from 9 patients with NHL and stored at 4 degrees C without further manipulation. They were then reinfused after high-dose chemotherapy. We monitored the change in colony-forming units-granulocyte, macrophage (CFU-GM) proliferation as well as plasma glucose, lactate and pH levels over the period of the study. In an attempt to maintain CFU-GM numbers, rhG-CSF was added to storage bags at collection and 48 h later. Our observations suggest that cell viability is well maintained and that CFU-GM numbers rise over the first 48 h of storage before falling rapidly. Metabolic changes cause a fall in the pH and glucose levels with a reciprocal rise in plasma lactate. The addition of rhG-CSF at a concentration of 10 ng/ml to cells in storage showed no detectable benefit. Following storage for 96 h, 77% (SEM +/- 8%) of the initial CFU-GM remained.

High-dose carmustine, etoposide and melphalan ('BEM') with autologous stem cell transplantation: a dose-toxicity study.

We have investigated the toxicity of dose-escalation of BCNU, etoposide and melphalan ('BEM') chemotherapy with autologous stem cell transplantation in patients with haematological malignancies. Seventy-two patients with haematological malignancies were treated with BCNU (600 mg/m2, 450 mg/m2 or 300 mg/m2), etoposide 2 g/m2 and melphalan 140 mg/m2 followed by autologous bone marrow transplantation (ABMT), n = 51, or autologous peripheral blood progenitor cell transplantation (APBPCT), n = 21. Liver and pulmonary function was monitored pretransplant and at regular intervals post-transplant. Mucositis was graded daily during in-patient stay. There was a significantly higher incidence of symptomatic pulmonary toxicity in the patients who received BCNU at 600 mg/m2 than in the other two groups, and there was a significant increase in the incidence of asymptomatic decrease in carbon monoxide (KCO) in the patients who received BCNU 450 mg/m2. There was no significant difference between the three groups in the incidence and severity of mucositis or in the incidence of transiently abnormal liver function. We conclude that etoposide at 2 g/m2 can be used without unacceptable mucositis. BCNU at 600 mg/m2 is associated with an unacceptably high incidence of lung toxicity, but at 450 mg/m2 there is minimal symptomatic lung toxicity.

Peripheral blood stem cell transplantation after high-dose therapy in patients with malignant lymphoma: a retrospective comparison with autologous bone marrow transplantation.

We report the results of peripheral blood progenitor cell (PBPC) harvesting in 22 patients with lymphoma who underwent leucapheresis after cells were mobilised using 3 g/m2 cyclophosphamide and G-CSF. In 19 patients, the total CFU-GM collected was greater than 7.5 x 10(4)/kg. These patients underwent successful autologous PBPC transplantation. This group of patients was compared to a historical group of 24 patients with lymphoma who underwent ABMT with the same conditioning chemotherapy. The time to engraftment of neutrophils to 0.5 x 10(9)/l was significantly reduced (median 11 days vs 19 days, P < 0.0001) and consequently in-patient stay was reduced (median 21 days vs 28 days, P < 0.001). Blood product support (median 3 vs 4 units blood, P = 0.02; median 15 vs 40 units platelets, P = 0.005) and use of TPN (median 0 days vs 8 days, P < 0.001) were reduced. We estimate a saving of approximately pounds 2370 per patient using PBPC for autologous transplantation compared to bone marrow progenitor cells. This saving is significant (P < 0.001).

Peripheral blood progenitor cell transplantation: a single centre experience comparing two mobilisation regimens in 67 patients.

Between June 1991 and January 1995 we performed 67 peripheral blood progenitor cell transplants (PBPCT). Ten patients (group 1) were mobilised with 7 gm/m2 of cyclophosphamide followed by daily G-CSF injections (5 micrograms/kg, subcutaneously). When the white cell count reached 1 x 10(9)/1 they were leukapheresed for 5 days. After stem cell infusion they received G-CSF (10 micrograms/kg/day) until the neutrophil count reached 1.5 x 10(9)/1. Fifty-six patients had PBPCs mobilised with 3 gm/m2 of cyclophosphamide followed by daily subcutaneous G-CSF (5 micrograms/kg) and PBPCs were harvested on 2 consecutive days, when the white cell count rose to 4 x 10(9)/1. After stem cell infusion this group did not receive G-CSF. In 47 of the 56 patients (group 2) adequate MNC (> or = 4 x 10(8)/kg) and/or CFU-GM (> or = 10 x 10(4)/kg) were obtained. Insufficient MNC and/or CFU-GM were obtained in 10 patients. They were therefore transplanted using a combination of bone marrow and peripheral blood progenitor cells (group 3). Overall 64 patients successfully engrafted. Median days to neutrophils > or = 0.5 x 10(9)/1 were 9 (range 8-13), 12 (range 8-25) and 11 (range 9-16) and to platelets > or = 50 x 10(9)/1 were 11 (range 9-23), 13 (range 9-90) and 16 (range 13-99) in groups 1, 2 and 3 respectively. Patients in group 1 had a faster neutrophil recovery than patients in group 2 (P = 0.0002). The three patients who failed to engraft all received a combination of autologous peripheral blood and bone marrow cells.

Autologous bone marrow transplantation for second or greater complete remission of acute myeloid leukaemia and acute lymphoblastic leukaemia.

Twenty patients with acute leukaemia in second or greater complete remission have undergone autologous bone marrow transplantation (ABMT) in our centre. Twelve patients had acute myeloid leukaemia (AML) and eight patients had acute lymphoblastic leukaemia (ALL). Six of the patients treated for AML remain in CR. Of the eight patients with ALL, all have died within one year of transplantation. In the patients with AML there was no relationship between the duration of previous CR and outcome of ABMT.

Autologous bone marrow transplantation for Hodgkin's disease--a five-year single centre experience.

The results from 40 patients who have undergone autologous bone marrow transplantation (ABMT) for relapsed or refractory Hodgkin's disease between March 1988 and September 1992 have been analysed. In contrast to our results in patients with relapsed HD, our results in patients with refractory HD are comparatively poor. Conventional salvage chemotherapy also seems inappropriate in these patients and we therefore believe they should be offered high-dose chemotherapy before their disease becomes refractory to conventionally scheduled regimens. Peripheral blood stem cell (PBSC) transplant now offers an attractive alternative to ABMT and may replace both intensive salvage chemotherapy and ABMT as the optimum treatment for patients who fail to respond to conventional chemotherapy regimens.

Two unusual neurological presentations of granulocytic sarcoma in Philadelphia positive chronic myeloid leukaemia.

Granulocytic sarcoma (GS) is a rare extramedullary tumour consisting of immature myeloid precursors. It occurs most commonly in association with myeloid leukaemias and myeloproliferative disorders. Rarely there may be no evidence of haematological malignancy. We describe neurological presentations of GS in two patients with Philadelphia (Ph) positive chronic myeloid leukaemia (CML). In both cases the bone marrow was in chronic phase at the time of presentation of the GS, but there was rapid subsequent transformation into the blastic phase.

Peripheral blood progenitor cell harvesting in multiple myeloma and malignant lymphoma.

Peripheral blood progenitor cells are being used increasingly as part of the treatment protocol for a variety of haematological malignancies. The most appropriate mobilisation therapy and the optimum collection procedures have yet to be fully elucidated. 28 patients with myeloma (9), NHL (11) and HD (8) underwent PBSC mobilisation and harvesting between November 1992 and October 1993. Two protocols were used; the myeloma group received high-dose cyclophosphamide, 7 g/m2 + G-CSF and were leucapheresed on 5 consecutive days during the recovery period using the Haemonetics V50 and the lymphoma group a lower dose of cyclophosphamide, 3 g/m2 + G-CSF followed by leucapheresis on 2 or 3 occasions using a Cobe Spectra. Median time to achieve a WBC of 1 x 10(9)/l during the recovery phase, was 14 days (11-16) and 10 days (9-15) respectively. Median numbers of MNC and CFU-GM collected for the myeloma group were 5.9 x 10(8)/kg (2.5-13.5) and 69.4 x 10(4)/kg (9.9-268.1) and for the lymphoma group. 5.1 x 10(8)/kg (1.2-11.1) and 35.4 x 10(4)/kg (1.2-129.7). Three patients with lymphoma had a low yield of CFU-GM, two of which did not proceed to autograft. The third patient failed to engraft and died despite receiving bone marrow backup. For the remaining 25 patients, median time to neuts > 0.5 x 10(9)/l and platelets > 50 x 10(9)/l was 9 (8-13) and 11 (9-23) days for the myeloma group and 12 (9-15) and 13 (9-180) days for the lymphomas. We found a strong correlation between CD34+ cells and CFU-GM from the last 9 patients. There is a correlation between CFU-GM infused and speed of engraftment. All patients who received > 10 x 10(4) CFU-GM/kg showed a rapid engraftment for neutrophils and platelets. In all cases, when > 4 x 10(8)/kg MNC were harvested, > 10 x 10(4) CFU-GM/kg were obtained. Sufficient cells for a rapid engraftment can be obtained from 2 leucaphereses in the majority of patients. The recovering peripheral blood WBC provides a good indicator of when to harvest. The target value of CFU-GM can be predicted by the number of cells harvested and by the number of CD34 positive cells in the leucapheresis product.

Thrombocytopenia and spontaneous rupture of the spleen associated with infectious mononucleosis.

Infectious mononucleosis (IM) normally has a benign, self-limiting course. Thrombocytopenia and spontaneous rupture of the spleen are two separate complications of the illness. We describe a patient who suffered from both these complications.

Specificity of the carboxypeptidase inhibitor from potatoes.

Carboxypeptidases from animal, plant, fungal, and bacterial sources were tested for their ability to bind to the carboxypeptidase inhibitor from Russet Burbank potatoes. Enzymes which participate in the degradation of dietary protein were partially purified from animal species as diverse as the cow and the limpet, and all were potently affected by the inhibitor. However, several zymogens of the enzymes in this group were tested and shown not to bind immobilized inhibitor. With the exception of an enzyme from mast cells and a novel carboxypeptidase A-like enzyme from bovine placenta, all animal carboxypeptidases which were not of digestive tract origin were not affected by the inhibitor. The inhibitor had no effect on the enzymic activities of all plant and most microbial carboxypeptidases. However, a strong association between the inhibitor and Streptomyces griseus carboxypeptidase has been noted previously and a low affinity (K(i) about 10 micromolar) for a carboxypeptidase G(1) from an acinetobacterium was found in this study.

Short-course intravenous antibiotics with oral quinolone prophylaxis in the treatment of neutropenic fever in autologous bone marrow or peripheral blood progenitor cell transplant recipients.

The effectiveness of short-course intravenous antibiotics concurrent with prophylactic oral ciprofloxacin in the treatment of neutropenic fever was studied in 81 patients undergoing autologous bone marrow or peripheral blood progenitor cell transplantation (ABMT or PBPCT). During the neutropenic period following ABMT or PBPCT, 10/81 (12%) patients did not require treatment with intravenous antibiotics. Seventy-one patients required antibiotics. Forty-seven of the 71 (66%) responded to 72 h treatment with gentamicin, azlocillin or ceftazidime, and vancomycin. Thirty-three of the 47 (70%) responders had a complete resolution of their fever with no further recurrence. Fourteen of the 47 responders developed a second fever between 2 and 25 days after stopping first-line antibiotics. Eleven of the 14 patients responded to a second course of intravenous antibiotics. Twenty-four of the 71 patients did not respond to intravenous antibiotics and were treated with intravenous amphotericin and the intravenous antibacterial agents were discontinued. Eighteen of the 24 patients responded to amphotericin. The 6 patients who had persistent fever resolved their temperature when their neutrophil count recovered. There were no deaths due to infection during the study. Short-duration intravenous antibiotics in conjuction with oral ciprofloxacin prophylaxis are a safe and effective treatment for neutropenic fever.