Calcaneotibial screws for immobilisation of the tarsocrural joint of dogs in extension: effect of the angle of screw placement on the force to failure in a canine cadaveric model

AIMS

To compare the force to failure under axial loading of a calcaneotibial screw placed approximately perpendicular to the tibia with that of a screw placed perpendicular to the calcaneus, when used to immobilise the tarsus in an ex vivo canine model.

METHODS

Twelve pairs of cadaveric hindlimbs from large breed dogs, without orthopaedic or soft tissue disease, were prepared by transecting the limb at the level of the stifle and stripping the limbs of all musculature from the stifle to mid-metatarsus, including removal of the common calcaneal tendon from all limbs. The limbs in each pair were randomly assigned to receive a calcaneotibial screw placed perpendicular to the long axis of either the calcaneus (C group) or the tibia (T group) with the tarsus in full extension. The distal limb was potted in resin and the proximal tibia was pinned to allow biomechanical testing in compressive loading. Testing was performed to apply an axial load using a material testing machine in a proximodistal direction through the tibia, advancing at a rate of 10 mm/second. The force to failure was recorded in kN and compared between groups.

RESULTS

The median force to failure of the C group was 0.86 (min 0.50; max 1.64) kN which was higher than the T group which had a median force to failure of 0.74 (min 0.26, max1.05) kN (p = 0.004). All modes of failure were by screw pull-out.

CONCLUSIONS

A calcaneotibial screw placed at an angle approximately perpendicular to the long axis of the calcaneus, has a higher force to failure under axial loading than a calcaneotibial screw that is placed at an angle approximately perpendicular to the tibia, in a canine cadaveric model.

CLINICAL RELEVANCE

A temporary calcaneotibial screw is a common method of immobilising the tarsus in extension to protect primary repair of a common calcaneal tendon injury. Placing a calcaneotibial screw perpendicular to the calcaneus may be a more reliable option for immobilisation of the tarsus to protect a common calcaneal tendon repair compared to screws placed perpendicular to the tibia. However extrapolation of these results into a clinical setting requires caution.

Analysis of a potential cluster of rhinovirus infections in patients and staff on two haemato-oncology wards

BACKGROUND

Human rhinoviruses (HRV) cause the common cold, increased mortality in patients attending elderly care facilities and significant morbidity as well as mortality in the post-transplantation setting.

OBJECTIVES

The aim of the study was to determine if there had been a breakdown in infection control practice in a large haemato-oncology centre. Molecular techniques had detected increased numbers of HRV in respiratory samples from patients and staff over a 6-week period. Typing was performed to investigate the possibility of transmission between individuals.

STUDY DESIGN

This was a retrospective study having detected HRV RNA in combined nose and throat swab samples that were collected from 13 individuals: 8 patients and 5 staff members, in the haemato-oncology wards of a tertiary referral centre in January and February 2011. The 5'NTR and the VP4/VP2 region were used for HRV typing.

RESULTS

All 3 HRV species were detected with 7 HRV-A, 1 HRV-B, 4 HRV-C and 1 untyped. None of the individuals were infected by the same HRV serotype. Three individuals had multiple samples collected: 1 patient had an HRV-B infection over a 4-week period, 1 patient had an HRV-A infection over 3 months and 1 staff member had an HRV-C infection over 1 week, each shedding an unchanged serotype throughout the whole period.

CONCLUSION

Nucleotide sequence analysis confirmed that there was no breakdown in infection control measures. No transmission incidents had occurred between patients and/or between staff and patients.

Platelet associated IgG and immune thrombocytopenia in lymphoproliferative and autoimmune disorders

Thrombocytopenia is frequently encountered in patients with lymphoproliferative disorders (LPD) and systemic erythromatosus (SLE) and to a lesser extent in association with other diseases such as rheumatoid arthritis (RA), pernicious anaemia (PA) and autoimmune haemolytic anaemia (AIHA). This report attempts to document the incidence of thrombocytopenia in these disorders, other than that overtly due to malignant infiltration or marrow suppression by drugs and to demonstrate, that in a significant proportion antibody mediated immune destruction of platelets can be confirmed by positive platelet antibody tests. Platelet associated IgG (PAIgG) was measured in all patients by a quantitative enzyme linked assay. Platelet antibodies were found in 11 of 24 (46%) thrombocytopenic patients with LPD, 10 of 16 (62%) patients with SLE and thrombocytopenia, and in all patients with RA and PA who had low platelet counts at the time of study. In addition, elevated PAIgG levels were found in the following non-thrombocytopenic patients: 9 of 43 (21%) patients with LPD, 2 of 12 (17%) with SLE, 2 of 12 (17%) with AIHA, 2 of 39 (5%) with PA and 5 of 61 (8%) patients with RA. The nature and the role of raised PAIgG levels in diseases other than autoimmune thrombocytopenia is controversial. Our reasons for interpreting these as true platelet autoantibodies in this selected group of disorders and the clinical implications of our results are discussed.

Clonal gammopathies following alemtuzumab-based reduced intensity conditioning haematopoietic stem cell transplantation: association with chronic graft-versus-host disease and improved overall survival

The presence of clonal gammopathies (CG) has been reported following both conventional myeloablative and autologous haematopoietic stem cell transplantation (HSCT). We monitored the occurrence of CG in a cohort of patients with myeloid malignancies receiving FBC (fludarabine-busulphan-alemtuzumab)-based reduced intensity conditioned (RIC) HSCT, and assessed its correlation with infections, graft-versus-host disease (GvHD) and survival. Serial serum protein electrophoresis was analysed in a total of 138 patients and CG were detected in 49 patients (36%). The predominant Ig isotype was IgG (82%). There was no difference in the incidence of viral infections between patient groups. However, patients with gammopathies were more likely to have had prior chronic GvHD (OR 2.7, 95% CI 1.3-5.5, P<0.001). On multivariate analysis, the only factors that were found to influence overall survival (OS) were presence of gammopathies, which was associated with an improved OS (OR 0.35 95% CI 0.14-0.86, P=0.02) as well as disease stage, patients with advanced disease having a higher risk of death (OR 2.20 95% CI 1.18-4.11, P=0.02). Disease stage was the only variable that influenced relapse incidence on multivariate analysis (OR 4.22 95% CI 1.82-9.78, P<0.01). Clonal gammopathies are a frequent but benign occurrence following alemtuzumab-based RIC HSCT, and their appearance may define a group of patients with a favourable overall outcome.

Sclerodermatous graft-versus-host disease: clinical spectrum and therapeutic challenges

Sclerodermatous graft-versus-host disease (GVHD) is a rare complication of bone marrow transplantation. While GVHD is often associated with the beneficial graft vs. tumour effect, it also contributes towards significant morbidity and mortality. No reliably effective treatment has yet been established. We present 10 patients with haematological malignancies who underwent an allogeneic stem cell transplant and developed sclerodermatous GVHD. Donor lymphocyte infusion administered for relapse or reducing donor T-cell chimerism was a known trigger for sclerodermatous GVHD in four of the patients. Treatment with immunosuppressants, psoralen plus ultraviolet A (PUVA) and extracorporeal photopheresis has been largely unsuccessful in their management. Intensive immunosuppression including the use of anti-CD20 monoclonal antibody may have contributed to relapse of leukaemia in one patient 10 years after her transplant. Sclerodermatous GVHD may occur without a preceding lichenoid stage. Clinical heterogeneity is common, although sclerodermatous GVHD has a predilection for the limbs. Treatment options are largely unsatisfactory if conventional immunosuppression fails. PUVA may give some symptomatic benefit and extracorporeal photopheresis seems to be less efficacious than previously published work suggests.

Lamivudine prophylaxis and treatment of hepatitis B Virus-exposed recipients receiving reduced intensity conditioning hematopoietic stem cell transplants with alemtuzumab

Individuals with past exposure to hepatitis B virus (HBV) may reactivate HBV following bone marrow transplantation. Alemtuzumab (CAMPATH)-based reduced intensity conditioning bone marrow transplantation has been associated with a high incidence of viral infections. Lamivudine prophylaxis for HBV should be instituted in this setting. The management of 240 CAMPATH-based reduced intensity conditioning bone marrow transplantation, carried out over an 8-year period at Kings College Hospital, was reviewed. Hepatitis B core total antibody (anti-HBc) testing identified recipients and donors with previous HBV exposure. Fifteen donor-recipient pairs were identified as being at risk of HBV reactivation. Eight recipients of anti-HBc negative donors were HBsAg negative, anti-HBc positive pre-transplantation. Five anti-HBc negative recipients received transplants from HBsAg negative, anti-HBc positive donors. Two HBV carrier recipients had one anti-HBc negative and one positive donor, respectively. Pre-transplant lamivudine prophylaxis was given to 8/10 (80%) anti-HBc positive recipients. Although HBsAg and HBV DNA were detected 4 months after bone marrow transplantation in one patient who did not receive prophylaxis, a good antiviral response was documented on starting lamivudine. The two HBV carrier recipients had stopped lamivudine at 8 and 31 months post-bone marrow transplantation, respectively, and died of liver failure with a sharp rise in HBV DNA levels. The five anti-HBc negative recipients with anti-HBc positive donors remained HBsAg and HBV DNA negative. Although lamivudine prophylaxis prevented HBV reactivation, it is unclear at what stage post-transplantation prophylaxis can be discontinued. Close monitoring of liver function tests (LFTs), HBsAg, and HBV DNA must be undertaken even after stopping antiviral prophylaxis.

Koebnerizing sclerodermatous graft-versus-host disease caused by donor lymphocyte infusion and interferon-α

Graft-versus-host disease (GvHD) is a common sequel to allogeneic bone marrow transplants, which may be accompanied by desirable graft-versus-tumour effects. Sclerodermatous GvHD is a rare subtype that is very difficult to treat. We report the first case of sclerodermatous GvHD as part of the Koebner phenomenon. We propose that donor lymphocyte infusion and interferon-alpha were involved in the pathogenesis of this case.

Cardiac presentation of ALK positive anaplastic large cell lymphoma

Cardiac involvement as an initial presentation of malignant lymphoma is a rare occurrence. We report the case of an immunocompetent 29-year-old male who presented with syncope and arrythmias secondary to a ventricular cardiac mass. Transcutaneous cardiac biopsy was non-diagnostic, therefore an open cardiac biopsy was performed from which a provisional diagnosis of a cardiac inflammatory pseudotumour was made. Six months after presentation, he developed several subcutaneous lesions with systemic symptoms. Histological and immunophenotypic review of the initial cardiac biopsy revealed features consistent with a diagnosis of CD30, ALK1 positive anaplastic large cell lymphoma (ALCL). Despite intensive treatment with combination chemotherapy, there was significant progression of disease, and he died 11 months after diagnosis. The overall prognosis of cardiac lymphoma remains poor, which may be due to the often late presentation of the tumour. To our knowledge, this is the first reported case of a cardiac ALK positive ALCL. Although rare, cardiac presentation of ALCL should be added to the list of differential diagnoses of cardiac lymphomas.

PNP with Waldenstrom's macroglobulinaemia

We describe a 65-year-old Caucasian man with Waldenstrom's macroglobulinaemia who developed paraneoplastic pemphigus (PNP) 3 years after his haematological diagnosis. This is a very rare malignancy that is associated with PNP. The evolution of PNP in this patient appears to exhibit the postulated immunological phenomenon of epitope spreading.

Patient, carer and health service outcomes of nurse-led early discharge after breast cancer surgery: a randomised controlled trial

Patients with breast cancer who require axillary clearance traditionally remain in hospital until their wound drains are removed. Early discharge has been shown to improve clinical outcomes, but there has been little assessment of the psychosocial and financial impact of early discharge on patients, carers and the health service. This study aimed to evaluate the effectiveness of a nurse-led model of early discharge from hospital. Main outcome measures were quality of life and carer burden. Secondary outcomes included patient satisfaction, arm morbidity, impact on community nurses, health service costs, surgical cancellations and in-patient nursing dependency. A total of 108 patients undergoing axillary clearance with mastectomy or wide local excision for breast cancer were randomised to nurse-led early discharge or conventional stay. Nurse-led early discharge had no adverse effects on quality of life or patient satisfaction, had little effect on carer burden, improved communication between primary and secondary care, reduced cancellations and was safely implemented in a mixed rural/urban setting. In total, 40% of eligible patients agreed to take part. Nonparticipants were significantly older, more likely to live alone and had lower emotional well being before surgery. This study provides further evidence of the benefits of early discharge from hospital following axillary clearance for breast cancer. However, if given the choice, most patients prefer to stay in hospital until their wound drains are removed.

Reduced-intensity rituximab-BEAM-CAMPATH allogeneic haematopoietic stem cell transplantation for follicular lymphoma is feasible and induces durable molecular remissions

The indolent non-Hodgkin's lymphomas are theoretically curable through allogeneic haematopoietic stem cell transplantation (allo-HSCT). The applicability of standard conditioning allo-HSCT is, however, restricted by its toxicity. Recently, reduced-intensity conditioning regimens have demonstrated efficacy with significantly reduced early morbidity and mortality. We examined the safety and efficacy of rituximab-BEAM-CAMPATH as reduced-intensity conditioning for allo-HSCT in follicular lymphomas. Minimal residual disease was assessed by polymerase chain reaction (PCR) for bcl-2/IgH translocations, and chimerism by X,Y-FISH or PCR amplification of short tandem repeat sequences. At a median follow-up of 521 days (371-719), four of five patients were alive and three were in complete molecular remission. Three patients required pre-emptive treatment for CMV reactivation. One succumbed to a perforated viscus and one had slowly progressive disease. A graft-versus-lymphoma effect was demonstrable and quantitative PCR for bcl-2/IgH may allow better accuracy in scheduling post-allograft rituximab and/or donor lymphocyte infusions. Although follow-up is short, reduced-intensity allo-HSCT with BEAM-CAMPATH conditioning appears to be safe, effective in inducing a molecular remission and is potentially curative. Further recruitment and much longer follow-up will be necessary to determine if this impacts favourably upon disease-free and overall survival.

In vivo CAMPATH-1H prevents GvHD following nonmyeloablative stem-cell transplantation

BACKGROUND

We have investigated a novel nonmyeloablative conditioning regimen in 44 patients with hematological malignancies. The median patient age was 41 years. Many of the patients had high-risk features, including 19 patients with a previous failed transplant.

METHODS

Recipient conditioning consisted of CAMPATH-1H 20 mg/day on Days -8 to -4, fludarabine 30 mg/m(2) on Days -7 to -3 and melphalan 140 mg/m(2) on Day -2. Thirty-six recipients received unmanipulated G-CSF mobilized PBSC from HLA identical siblings and eight received unmanipulated BM from MUD. GvHD prophylaxis was with CYA alone for 38 patients and CYA plus MTX for six sibling recipients.

RESULTS

Forty-two of the 43 evaluable patients had sustained engraftment. Results of chimerism analysis using microsatellite PCR indicate that 18 of 31 patients studied were full donor chimeras, while the other patients were mixed chimeras in one or more lineages. At a median follow-up of 9 months (range, 3-29 months) 33 patients remain alive in CR, or with no evidence of disease progression. Seven patients relapsed or progressed post-transplant and four of them subsequently died. Four patients died from regimen-related complications. There were no cases of Grades III-IV acute GvHD. Only two patients developed Grade II acute GvHD and only one had chronic GvHD. The estimated probability of non-relapse mortality at 1 year was 11%.Results: Although longer follow-up is needed to establish the long-term remission rates, this study demonstrates that this nonmyeloablative preparative regimen is associated with durable engraftment, minimal toxicity and low incidence of GvHD.

Fatal donor-derived Epstein-Barr virus-associated post-transplant lymphoproliferative disorder following reduced intensity volunteer-unrelated bone marrow transplant for myelodysplastic syndrome

Post-transplant lymphoproliferative disorders (PTLD) are a well recognised complication of conventional haemopoietic stem cell transplantation (HSCT). Reduced intensity HSCT involves intensive immunosuppression to permit engraftment. Thirty reduced intensity transplants with the FBC (fludarabine 150 mg/m2, busulphan 8 mg/m2, CAMPATH-1H 100 mg) protocol have been performed at our centre, with one confirmed EBV-positive PTLD. The female recipient developed a perforated viscus day +191 following HSCT from a volunteer unrelated male donor. A large caecal mass and a retroperitoneal abscess were excised, revealing an EBV-positive diffuse large B cell lymphoma confirmed by FISH to be of donor origin. More experience is required before the risk of PTLD in this setting can be assessed.

Granulocyte transfusion: a review

Neutrophils are the body's main defence against invasion by bacteria and fungi and, below a level of 1 x 10(9)/l, there is a direct relationship between their circulating number and the risk of systemic infection. Despite advances in supportive care, such as improved broad-spectrum antibiotics and the haemopoietic growth factors, neutropenia following myelosuppressive chemotherapy for malignant disease remains the most important cause of treatment-related morbidity and mortality and its most important dose-limiting toxicity. Although there is clear theoretical, experimental and anecdotal clinical evidence supporting the use of transfused granulocytes to prevent and treat infection in neutropenia, early attempts at exploiting this clinically were unsuccessful, mainly because of difficulties in collecting a sufficient number of cells. Improvements in the technology of collection, including the use of red cell sedimenting agents, glucocorticoids and, more recently, granulocyte-colony-stimulating factor, now allow granulocyte doses within the therapeutic range to be routinely collected. Preliminary evidence suggests clinical efficacy. However, well-designed trials with clinically relevant end-points will be required before granulocyte transfusion can become part of routine clinical practice.

The retinoblastoma family member, p107, is active in non-dividing monocyte-derived dendritic cells

A member of the retinoblastoma family of cell cycle regulatory proteins, p107, is not normally expressed in non-cycling cells. We demonstrate here that p107 is expressed in monocytes as they differentiate into dendritic cells under the influence of granulocyte-macrophage colony-stimulating factor and interleukin 4, a process shown not to involve cellular proliferation. We show that p107 is localized to the nucleus of these cells and is active, in that it binds an E2F-DNA binding site, together with E2F transcription factors. These findings suggest a hitherto unknown role for p107 in non-proliferating dendritic cells that warrants further investigation.

A clinically applicable method for the ex vivo generation of antigen-presenting cells from CD34+ progenitors

BACKGROUND AND OBJECTIVES

Dendritic cells (DCs), the most potent of antigen-presenting cells, can be generated in vitro from bone marrow or blood progenitor cells. We have developed a method for producing such cells from mobilised peripheral blood CD34+ cells in the absence of bovine products.

METHODS

The culture system developed used X-Vivo 10 culture medium with 10% autologous serum, rhGM-CSF, rhTNF-alpha and rhIL-4. Large-scale cultures were performed in Stericell 12 inch x 15 inch culture bags.

RESULTS

In 12-small-scale experiments, over 14 days, there was a median 38-fold increase in cell numbers of which 12.8% were DCs as defined by immunophenotyping. These cells had potent DC activity in functional assays. In two clinical-scale experiments, a 5.7- and 10-fold expansion of total cell numbers was obtained, with 8.2 and 18% of the final population being DCs, respectively.

CONCLUSION

This system is suitable for clinical application.

The role of apoptosis, proliferation, and the Bcl-2-related proteins in the myelodysplastic syndromes and acute myeloid leukemia secondary to MDS

Bone marrow CD34(+) cell apoptosis (annexin V), proliferation (Ki-67), and Bcl-2-related protein expression was evaluated by flow cytometry in 102 patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia secondary to MDS (MDS-AML) and in 30 normal donors (NBM). Apoptosis was significantly increased in refractory anemia (RA)/RA with ringed sideroblasts (RARS) (56.9% [20.4%-93.6%]) and refractory anemia with excess blasts (RAEB) (51.2% [25.2%-76. 6%]) compared with NBM (16.7% [3.4%-35.3%], P <.0001). In RA/RARS, apoptosis always exceeded proliferation (Ki-67-positivity, 26.1% [9.5%-47.8%]; apoptosis:proliferation ratio 2.08 [1.15-3.63]); whereas in RAEB, this ratio equalized (1.14 [0.93-2.08]) due to increased proliferation (40.4% [22%-69.5%]). Progression to RAEB in transformation (RAEB-t)/MDS-AML was associated with a significant reduction in apoptosis (22.3% [2.1%-53.2%]; P <.0001) and proliferation (16.8% [1.9%-75.8%); P =.04; ratio 1.69 [0.16-12.21]). Pro-apoptotic (Bax/Bad) versus anti-apoptotic (Bcl-2/Bcl-X) Bcl-2-related protein ratios were increased in RA/RARS compared with NBM (2.57 [1.93-9.42] versus 1.89 [0.65-4.1]; P =.06), whereas disease progression was associated with significantly reduced ratios (1.16 [0.06-3.32]; P <.0001) due primarily to increased Bcl-2 expression. Apoptosis and Bax/Bad:Bcl-2/Bcl-X ratio were inversely correlated with both International Prognostic Scoring System score and cytogenetic risk group; highest levels observed in patients with low score and/or good risk cytogenetics. There was a trend toward an association between Bcl-2-related protein expression and apoptosis (P =.07). This study indicates that MDS progression arises through multiple hits that alter levels of CD34(+) cell apoptosis and proliferation. Early disease is associated with excessive apoptosis and elevated ratio of apoptosis to proliferation. Increased proliferative rates are observed in RAEB, whereas leukemic transformation arises through inhibition of apoptosis rather than excessive cell growth. Although disease progression is accompanied by a fall in pro-apoptotic versus anti-apoptotic Bcl-2-related protein ratios, heterogeneity in patterns of protein expression indicates that factors additional to Bcl-2 family members play a role in the deregulated apoptosis in MDS. (Blood. 2000;96:3932-3938)

In vivo CAMPATH-1H prevents graft-versus-host disease following nonmyeloablative stem cell transplantation

A novel nonmyeloablative conditioning regimen was investigated in 44 patients with hematologic malignancies. The median patient age was 41 years. Many of the patients had high-risk features, including 19 patients with a previous failed transplant. Recipient conditioning consisted of CAMPATH-1H, 20 mg/day on days -8 to -4; fludarabine, 30 mg/m(2) on days -7 to -3; and melphalan, 140 mg/m(2) on day -2. Thirty-six recipients received unmanipulated granculocyte colony-stimulating factor-mobilized peripheral blood stem cells from HLA-identical siblings, and 8 received unmanipulated marrow from matched unrelated donors. GVHD prophylaxis was with cyclosporine A alone for 38 patients and cyclosporine A plus methotrexate for 6 sibling recipients. Forty-two of the 43 evaluable patients had sustained engraftment. Results of chimerism analysis using microsatellite polymerase chain reaction indicate that 18 of 31 patients studied were full-donor chimeras while the other patients were mixed chimeras in one or more lineages. At a median follow-up of 9 months (range 3 to 29 months), 33 patients remain alive in complete remission or with no evidence of disease progression. Seven patients relapsed or progressed post-transplantation, and 4 of them subsequently died. Four patients died of regimen-related complications. There were no cases of grades III-IV acute GVHD. Only 2 patients developed grade II acute GVHD, and only 1 had chronic GVHD. The estimated probability of nonrelapse mortality was 11%. Although longer follow-up is needed to establish the long-term remission rates, this study demonstrates that this nonmyeloablative preparative regimen is associated with durable engraftment, minimal toxicity, and low incidence of GVHD.

The PI3 kinase, p38 SAP kinase, and NF-kappaB signal transduction pathways are involved in the survival and maturation of lipopolysaccharide-stimulated human monocyte-derived dendritic cells

As a dendritic cell (DC) matures, it becomes more potent as an antigen-presenting cell. This functional change is accompanied by a change in DC immunophenotype. The signal transduction events underlying this process are poorly characterized. In this study, we have investigated the signal transduction pathways involved in the lipopolysaccharide (LPS)-induced maturation of human monocyte-derived DCs (MoDCs) in vitro. We show that exposure of immature MoDCs to LPS activates the p38 stress-activated protein kinase (p38SAPK), extracellular signal-regulated protein kinase (ERK), phosphoinositide 3-OH kinase (PI3 kinase)/Akt, and nuclear factor (NF)-kappaB pathways. Studies using inhibitors demonstrate that PI3 kinase/Akt but not the other pathways are important in maintaining survival of LPS-stimulated MoDCs. Inhibiting p38SAPK prevented activation of the transcription factors ATF-2 and CREB and significantly reduced the LPS-induced up-regulation of CD80, CD83, and CD86, but did not have any significant effect on the LPS-induced changes in macropinocytosis or HLA-DR, CD40, and CD1a expression. Inhibiting the NF-kappaB pathway significantly reduced the LPS-induced up-regulation of HLA-DR as well as CD80, CD83, and CD86. Inhibiting the p38SAPK and NF-kappaB pathways simultaneously had variable effects depending on the cell surface marker studied. It thus appears that different aspects of LPS-induced MoDC maturation are regulated by different and sometimes overlapping pathways.

Monocyte-derived dendritic cells do not proliferate and are not susceptible to retroviral transduction

Dendritic cells may be generated ex vivo from CD34+ progenitor cells or peripheral blood mononuclear cells. Initial reports suggested that monocyte-derived dendritic cells (MoDCs) arise from a proliferating precursor and several groups subsequently reported successful retroviral transduction of these cells, again implying that cell division occurs. As this is of importance in the development of immunotherapy protocols, we investigated whether monocytes proliferate as they differentiate into MoDCs and also their susceptibility to retroviral transduction. During MoDC differentiation, there was a 51 +/- 12% reduction in cell number, 98% of cells were in G0/G1, no DNA synthesis was detectable and the cell cycle regulatory proteins pRb and p130 were in the hypophosphorylated forms observed in non-cycling cells. As expected from these results, MoDCs were refractory to transduction with a GALV1 pseudotyped Moloney murine leukaemia virus (MoMLV)-based retroviral vector. In contrast, generation of DCs from purified CD34 progenitors was accompanied by rapid entry into the cell cycle and a 41.1-fold cell expansion at the end of 14 d culture.

Effect of changes in expression of the amphotropic retroviral receptor PiT-2 on transduction efficiency and viral titer: implications for gene therapy

The aim of this study was to quantify the impact of amphotropic retroviral receptor (PiT-2) levels on susceptibility to transduction and to determine whether the low level of PiT-2 found on CD34+ hematopoietic cells is within the range likely to compromise gene transfer. Receptor-deficient Chinese hamster ovary (CHO) cells were transfected with a PiT-2 construct that could be induced by the removal of tetracycline. The level of PiT-2 expression measured by virus binding in uninduced and in fully and partially induced transfectants correlated with the efficiency of transduction by an amphotropic retroviral reporter vector. Fully induced CHO-PiT-2 cells gave apparent viral titers similar to NIH 3T3 fibroblasts while addition of tetracycline reduced titers by up to 140-fold. Binding of the same vector preparation to purified CD34+ peripheral blood stem cells (PBSCs) was always less than to uninduced CHO-PiT-2 transfectants even after preincubation in 10-ng/ml concentrations of IL-3, IL-6, and stem cell factor, which increased retroviral binding by an average of 35%. The level of expression of the amphotropic retroviral receptor PiT-2 thus significantly limits transduction efficiency within the range observed in target cells of importance in human gene therapy.

ESHAP and G-CSF is a superior blood stem cell mobilizing regimen compared to cyclophosphamide 1.5 g m(-2) and G-CSF for pre-treated lymphoma patients: a matched pairs analysis of 78 patients

Cyclophosphamide 1.5 g m(-2) followed by granulocyte colony-stimulating factor (G-CSF) is an effective peripheral blood stem cell (PBSC) mobilizing regimen, but has limited anti-lymphoma activity. We therefore assessed the mobilizing potential of ESHAP (etoposide, ara-C, methylprednisolone and cisplatin), a potent second-line lymphoma regimen followed by G-CSF. The results were compared in 78 patients with relapsed or resistant lymphomas with the use of cyclophosphamide 1.5 g m(-2) followed by G-CSF in a matched pairs analysis, matching the ESHAP recipients (for predetermined prognostic factors) from a cohort of 178 lymphoma patients mobilized with cyclophosphamide and G-CSF. The total numbers of mononuclear cells collected at apheresis was similar with both regimens but ESHAP plus G-CSF resulted in a significantly higher percentage of CD34+ cells, absolute number of CD34+ cells and GM-CFC (all with P-values < 0.001). The number of patients requiring only one apheresis harvest to achieve a CD34+ cell yield of > 2.0 x 10(6) kg(-1) was greatly increased in the ESHAP recipients (56/78 vs 17/78, P < 0.001). The total number of progenitor cells collected was not significantly different with the two mobilization regimens because of this higher number of apheresis in the cyclophosphamide group. The proportion of patients who failed to achieve a minimum CD34+ cell target of 1 x 10(6) kg(-1) with the pooled harvests was less in the ESHAP arm (four patients vs nine patients) despite an increased number of aphereses in the cyclophosphamide recipients. ESHAP plus G-CSF is well tolerated and is an excellent mobilization regimen in patients with pre treated lymphoma.

An unusual case of intrapulmonary granulocytic sarcoma presenting as interstitial pneumonitis following allogeneic bone marrow transplantation for acute myeloid leukaemia and responding to donor lymphocyte infusion

We report a 45-year-old female with AML who underwent a T cell-depleted sibling allograft and relapsed a year later with extramedullary disease involving the lung parenchyma and presenting with the clinical and radiological features of interstitial pneumonitis. The patient was treated with donor lymphocyte infusion (DLI) resulting in complete resolution of the radiological signs. The unusual presentation and the management options are discussed.

High-dose BEAM chemotherapy with autologous haemopoietic stem cell transplantation for Hodgkin's disease is unlikely to be associated with a major increased risk of secondary MDS/AML

Hodgkin's disease is curable in the majority of patients, although a proportion of patients are resistant to or relapse after initial therapy. High-dose therapy with autologous stem cell support has become the standard salvage therapy for patients failing chemotherapy, but there have been reports of a high incidence of myelodysplasia/acute myeloid leukaemia (MDS/AML) following such treatment. Patients who receive such therapy form a selected group, however, who have already been subjected to other leukaemogenic factors, such as treatment with alkylating agents. In order to ascertain the true risk of MDS/AML, comparison must be made with other patients subjected to the same risks but not undergoing transplantation. We report a retrospective comparative study of 4576 patients with Hodgkin's disease from the BNLI and UCLH Hodgkin's databases, which includes 595 patients who have received a transplant. Statistical analysis including Cox's proportional hazards multivariate regression model with time-dependent covariates was employed. This analysis reveals that the risk of developing MDS/AML was dominated by three factors, namely quantity of prior therapy (relative risk [RR] 2.01, 95% confidence intervals [CI] 1.49-2.71, for each treatment block, P < 0.0001) and whether the patient had been exposed to MOPP (RR 3.61, 95% CI 1.64-7.95, P = 0.0009) or lomustine chemotherapy (RR 4.53, 95% CI 1.96-10.44, P = 0.001). Following adjustment for these factors in the multivariate model the relative risk associated with transplantation was 1.83 (95% CI 0.66-5.11, P = 0.25). This study provides no evidence of a significantly increased risk of MDS/AML associated with BEAM therapy and autologous transplantation in Hodgkin's disease. Concern over MDS/AML should not mitigate against the timely use of this treatment modality.

Outcome of secondary myeloid malignancy in Hodgkin's disease: the BNLI experience

In Hodgkin's disease where the majority of patients are long-term survivors secondary myeloid malignancies are a well-documented complication. The survival of those who develop secondary myelodysplasia/acute myeloid leukaemia (MDS/AML) is historically said to be extremely poor. This study from the BNLI database of over 4900 patients with Hodgkin's disease reports long-term follow-up of 30 patients with secondary MDS/AML. Five patients have survived at least 5 yr (1>12 yr) from the time of diagnosis of AML. These patients were significantly younger (p=0.03) than those who succumbed to this complication and each also had standard or favourable risk cytogenetics. The actuarial 5- and 10-yr survival rates are 17.4% (7.7-34.9%, 95% CI) and 8.7% (1.9-31.7%, 95% CI), respectively. There is therefore a subgroup of patients who will achieve long-term survival despite the development of secondary myeloid malignancy.

Back-up bone marrow is frequently ineffective in patients with poor peripheral-blood stem-cell mobilization

PURPOSE

To assess hematologic recovery and procedure-related mortality in patients who received high-dose therapy with stem-cell support, in whom the peripheral-blood stem-cell (PBSC) collection fails (CD34+ cells < 1 x 10(6)/kg). The predictive value of granulocyte-monocyte colony-forming cell (GM-CFC) measurements and the value of bone marrow obtained after PBSC collection failure was assessed.

PATIENTS AND METHODS

The study group comprised 324 consecutive patients mobilized with granulocyte colony-stimulating factor (G-CSF) and cyclophosphamide (273 patients), G-CSF with other chemotherapy (37 patients), and G-CSF alone (14 patients). Between one and four aphereses were performed.

RESULTS

In 51 of 324 patients, there was failure to obtain 1 x 10(6)/kg CD34+ cells. Twenty-three patients had greater than 1 x 10(5)/kg GM-CFC; 22 patients proceeded to high-dose therapy. Neutrophil recovery occurred within 21 days, but platelet independence was delayed (> 28 days) in eight patients. Of 28 patients with less than 1 x 10(5)/kg GM-CFC, six received high-dose therapy with PBSC alone and five had delayed engraftment. Twelve patients with less than 1 x 10(5)/kg GM-CFC received high-dose therapy supported by bone marrow collected after PBSC collection failure. Eleven patients were assessable for engraftment; four patients had slow (> 21 days) or delayed (> 28 days) neutrophil recovery and eight patients had delayed platelet recovery. In the group of patients who received less than 1 x 10(5)/kg GM-CFC, there were five procedure-related deaths.

CONCLUSION

This study shows that delayed hematologic recovery is frequent if less than 1 x 10(6)/kg CD34+ cells are infused after high-dose therapy, particularly with GM-CFC less than 1 x 10(5)/kg. The procedure-related mortality in this latter group is high. In most patients whose PBSC collection contains less than 1 x 10(5)/kg GM-CFC, the use of bone marrow cells does not improve engraftment, which suggests that poor PBSC mobilization usually indicates poor marrow function.

Feasibility of multidrug resistance (MDR-1) gene transfer in patients undergoing high-dose therapy and peripheral blood stem cell transplantation for lymphoma

We have performed a pilot study of MDR-1 gene transfer in patients receiving CD34-selected peripheral blood stem cell (PBSC) transplant for lymphoma. To ensure minimum engraftment thresholds and facilitate CD34 purification, mobilisation of > 2 x 10(6) CD34 cells/kg was a condition for recruitment. Of 11 patients counselled for study entry, only five achieved this target in a single apheresis. In three consenting patients, purified CD34 cells were exposed to A12M1 MDR-1 retroviral supernatant for 6 h, cryopreserved then thawed and readministered following ablative chemotherapy. No delay in engraftment was observed, although one patient received additional back-up cells. Gene transfer was demonstrated by polymerase chain reaction (PCR) for vector-derived MDR-1 cDNA sequence in all cases. Analysis of peripheral blood and bone marrow cells after transplant has, however, shown no evidence of in vivo gene transfer with a follow-up of 12, 15 and 18 months. The effect of MDR-1 substrate drugs has not yet been tested as all patients remain in clinical and radiological remission of their lymphoma. These results confirm the difficulty of achieving in vivo gene transfer in human haemopoietic cells and indicate major logistical constraints in PBSC mobilisation in patients with relapsed and resistant disease in whom initial studies are appropriate.

Granulocyte-macrophage colony stimulating factor receptor alpha and beta chain complexes can form both high and intermediate affinity functional receptors

Scatchard analysis of primary human haemopoietic cells using iodinated GM-CSF suggests that there are low, intermediate and high affinity classes of the GM-CSF receptor. To investigate the molecular basis of this, we generated a clone of transfected NIH3T3 cells that constitutively expressed the human granulocyte-macrophage colony stimulating factor receptor (GM-CSF R) beta chain and inducibly expressed the human GM-CSF R alpha chain. In the cells fully induced to express the alpha chain the overall level of expression of the alpha and beta chains at the cell surface was comparable with that found in primary haemopoietic cells and cell lines. When cells were partially induced to express the alpha chain, the alpha:beta ratio determined by antibody binding was approximately 1:1 and Scatchard analysis revealed a single class of intermediate affinity receptors (Kd = 614+/-88 pM). In cells with fully induced alpha chain expression, the alpha:beta ratio was approximately 3:1 and there was a switch to a dual high and low affinity receptor with K(d)s of 67+/-32 pM and 1.7+/-0.56 nM respectively. The change from intermediate to high affinity was not associated with changes in alphabeta stoichiometry as detected by cross-linking with radiolabelled GM-CSF and gel electrophoresis. Both the high and intermediate affinity receptors were able to activate the STAT 5 and the MAP kinase pathways, although there was a difference in the ligand dose-response curves which was compatible with the different affinities of the receptors. It is proposed that the switch from an intermediate to high affinity receptor was due to the availability of free alpha chains presenting ligand to the alphabeta chain complexes at the surface of the cell membrane.