Role of plerixafor in autologous stem cell mobilization with vinorelbine chemotherapy and granulocyte-colony stimulating factor in patients with myeloma: a phase II study (PAV-trial)

Current practice in Switzerland for the mobilization of autologous stem cells in patients with myeloma is combining vinorelbine chemotherapy and granulocyte-colony stimulating factor (G-CSF) cytokine stimulation. We prospectively investigated adding intravenous plerixafor to the vinorelbine/G-CSF combination (VGP), and compared it with vinorelbine/plerixafor (VP) and G-CSF/plerixafor (GP) combinations. In a final cohort (VP-late), plerixafor was given on the first day of CD34 + cells increasing to > 15 000/mL peripheral blood. Four consecutive cohorts of 10 patients with myeloma were studied. We observed that intravenously administered plerixafor can be safely combined with vinorelbine/G-CSF. VGP was superior in mobilizing peripheral stem and progenitor cells compared to the three double combinations (VP, GP and VP-late), and GP mobilized better than VP. Our data indicate that the triple combination of VGP is an efficient strategy to collect autologous CD34 + cells, with G-CSF contributing predominantly in this concept. Plerixafor can be safely added to G-CSF and/or vinorelbine chemotherapy.

In vitro detection of cytotoxic T and NK cells in peripheral blood of patients with various drug-induced skin diseases

BACKGROUND: Cytotoxic cells are involved in most forms of drug-induced skin diseases. Till now, no in vitro test addressed this aspect of drug-allergic responses. Our report evaluates whether drug-induced cytotoxic cells can be detected in peripheral blood of nonacute patients with different forms of drug hypersensitivity, and also whether in vitro detection of these cells could be helpful in drug-allergy diagnosis. METHODS: GranzymeB enzyme-linked immunosorbent spot-forming (ELISPOT) and cell surface expression of the degranulation marker CD107a were evaluated on peripheral blood mononuclear cells from 12 drug-allergic patients in remission state and 16 drug-exposed healthy controls. RESULTS: In 10/12 allergic patients culprit but not irrelevant drug elicited granzymeB release after 48-72 h stimulation. It was clearly positive in patients with high proliferative response to the drug, measured in lymphocyte transformation tests. In patients, who showed moderate or low proliferation and low drug-response in granzymeB ELISPOT, overnight preincubation with interleukin (IL)-7/IL-15 enhanced drug-specific granzymeB release and allowed to clearly identify the offending agent. CD107a staining was positive on CD4+/CD3+, CD8+/CD3+ T cells as well as CD56+/CD3- natural killer cells. None of the drug-exposed healthy donors reacted to the tested drugs and allergic patients reacted only to the offending, but not to tolerated drugs. CONCLUSION: GranzymeB ELISPOT is a highly specific in vitro method to detect drug-reacting cytotoxic cells in peripheral blood of drug-allergic patients even several years after disease manifestation. Together with IL-7/IL-15 preincubation, it may be helpful in indentifying the offending drug even in some patients with weak proliferative drug-response.

High-dose melphalan with or without stem cell support before myeloablative allo-SCT for remission induction in patients with advanced relapsed or refractory AML

Treatment strategies for relapsed/refractory AML are limited and disappointing. Recently, high-dose melphalan (HDM) chemotherapy and autologous hematopoietic SCT (HSCT) has been proposed for AML re-induction. We investigated the impact of HDM remission induction in highly advanced relapsed/refractory AML patients planned for allogeneic HSCT. A total of 23 patients with relapsed/refractory AML were prospectively scheduled for HDM with or without stem cell support followed by myeloablative allogeneic HSCT. Patients included nine individuals with a history of previous HSCT (seven allogeneic, two autologous). A total of 18 patients (78%) achieved a leukemia-free state and an additional four had substantial reduction of the initial leukemia burden warranting treatment continuation. There were no differences between patients with or without immediate stem cell support regarding mucositis or other organ toxicity. A total of 20 patients proceeded to myeloablative allogeneic HSCT. Outcome of allogeneic HSCT was poor: 11 patients (55%) relapsed, 7 patients (35%) died from TRM and only 2 patients (10%) were alive at the last follow-up. Our study shows that HDM is effective in inducing a leukemia-free state in patients with highly advanced relapsed/refractory AML. Leukemia burden reduction with HDM, however, did not translate into improved OS.

High activity of sorafenib in FLT3-ITD-positive acute myeloid leukemia synergizes with allo-immune effects to induce sustained responses

Preliminary evidence suggests that the multikinase inhibitor sorafenib has clinical activity in FLT3-ITD-positive (FLT3-ITD) acute myeloid leukemia (AML). However, the quality and sustainability of achievable remissions and clinical variables that influence the outcome of sorafenib monotherapy are largely undefined. To address these questions, we evaluated sorafenib monotherapy in 65 FLT3-ITD AML patients treated at 23 centers. All but two patients had relapsed or were chemotherapy-refractory after a median of three prior chemotherapy cycles. Twenty-nine patients (45%) had undergone prior allogeneic stem cell transplantation (allo-SCT). The documented best responses were: hematological remission in 24 patients (37%), bone marrow remission in 5 patients (8%), complete remission (with and without normalization of peripheral blood counts) in 15 patients (23%) and molecular remission with undetectable FLT3-ITD mRNA in 10 patients (15%), respectively. Seventeen of the patients without prior allo-SCT (47%) developed sorafenib resistance after a median treatment duration of 136 days (range, 56-270 days). In contrast, allo-SCT patients developed sorafenib resistance less frequently (38%) and significantly later (197 days, range 38-225 days; P=0.03). Sustained remissions were seen exclusively in the allo-SCT cohort. Thus, sorafenib monotherapy has significant activity in FLT3-ITD AML and may synergize with allogeneic immune effects to induce durable remissions.Leukemia advance online publication, 8 May 2012; doi:10.1038/leu.2012.105.

Mesenchymal stem cell therapy following muscle trauma leads to improved muscular regeneration in both male and female rats

Mesenchymal stem cell (MSC) therapy has the potential to enhance muscular regeneration. In previous publications, our group was able to show a dose-response relationship in female animals between the amount of transplanted cells and muscle force. The impact of sex on the regeneration of musculoskeletal injuries following MSC transplantation remains unclear.

[Stem-cell-based approaches for treating inner ear diseases]

The capacity of stem cells to regenerate lost tissue cells has gained recognition among physicians. Despite the successful use of blood stem cells for treating blood cancers, other stem cell types have not yet been widely introduced into clinical practice. Therapy options involving stem cells for inner ear diseases consequently have not been implemented. Nonetheless, several reports have recently been published describing the generation of morphologically and immunologically distinctive inner ear cell types-such as hair cells, supporting cells, and spiral ganglion neurons-from stem cells. Although promising, all of these studies still lack functional results regarding hearing restoration or vestibular function.

Isotype-specific detection of ABO blood group antibodies using a novel flow cytometric method

Several methods to detect anti-A/B antibodies based on haemagglutination and haemolysis have been described. These methods measure predominantly anti-A/B immunoglobulin (Ig)M, whereas anti-A/B IgG and IgG subclasses are less well examined. We established a flow cytometry method (ABO-fluorescence-activated cell sorting; ABO-FACS) to quantify binding of anti-A/B IgM, IgG and IgG subclasses to human A or B red blood cells. Anti-A/B IgM were present in the majority of 120 blood donors, as expected from blood group typing. The sensitivity and specificity of anti-A/B IgM to predict the blood group was 93% and 96% respectively. Anti-A/B IgG was found in 34/38 blood group O samples (89%). Anti-B IgG in blood group A or anti-A IgG in blood group B was present in 4/28 (14%) and 1/28 (4%) samples, respectively, and absent in 26 AB sera. IgG2 was the predominant IgG subclass. The correlation of anti-A/B IgM and IgG in the ABO-FACS with haemagglutination titres was 0.870 and 0.783, respectively (n = 240; P < 0.001) whereas the comparison of ABO-FACS with ABO-enzyme-linked immunosorbent assay was less significant. In conclusion, ABO-FACS is a valid method to quantify anti-A/B IgM, IgG and IgG subclasses. It opens the possibility of isotype-specific monitoring of anti-A/B antibodies levels after ABO-incompatible solid organ and stem cell transplantation.

Novel cell-free strategy for therapeutic angiogenesis: in vitro generated conditioned medium can replace progenitor cell transplantation

BACKGROUND: Current evidence suggests that endothelial progenitor cells (EPC) contribute to ischemic tissue repair by both secretion of paracrine factors and incorporation into developing vessels. We tested the hypothesis that cell-free administration of paracrine factors secreted by cultured EPC may achieve an angiogenic effect equivalent to cell therapy. METHODOLOGY/PRINCIPAL FINDINGS: EPC-derived conditioned medium (EPC-CM) was obtained from culture expanded EPC subjected to 72 hours of hypoxia. In vitro, EPC-CM significantly inhibited apoptosis of mature endothelial cells and promoted angiogenesis in a rat aortic ring assay. The therapeutic potential of EPC-CM as compared to EPC transplantation was evaluated in a rat model of chronic hindlimb ischemia. Serial intramuscular injections of EPC-CM and EPC both significantly increased hindlimb blood flow assessed by laser Doppler (81.2+/-2.9% and 83.7+/-3.0% vs. 53.5+/-2.4% of normal, P<0.01) and improved muscle performance. A significantly increased capillary density (1.62+/-0.03 and 1.68+/-0.05/muscle fiber, P<0.05), enhanced vascular maturation (8.6+/-0.3 and 8.1+/-0.4/HPF, P<0.05) and muscle viability corroborated the findings of improved hindlimb perfusion and muscle function. Furthermore, EPC-CM transplantation stimulated the mobilization of bone marrow (BM)-derived EPC compared to control (678.7+/-44.1 vs. 340.0+/-29.1 CD34(+)/CD45(-) cells/1x10(5) mononuclear cells, P<0.05) and their recruitment to the ischemic muscles (5.9+/-0.7 vs. 2.6+/-0.4 CD34(+) cells/HPF, P<0.001) 3 days after the last injection. CONCLUSIONS/SIGNIFICANCE: Intramuscular injection of EPC-CM is as effective as cell transplantation for promoting tissue revascularization and functional recovery. Owing to the technical and practical limitations of cell therapy, cell free conditioned media may represent a potent alternative for therapeutic angiogenesis in ischemic cardiovascular diseases.

Should the standard dimethyl sulfoxide concentration be reduced? Results of a European Group for Blood and Marrow Transplantation prospective noninterventional study on usage and side effects of dimethyl sulfoxide.

BACKGROUND Dimethyl sulfoxide (DMSO) is essential for the preservation of liquid nitrogen-frozen stem cells, but is associated with toxicity in the transplant recipient. STUDY DESIGN AND METHODS In this prospective noninterventional study, we describe the use of DMSO in 64 European Blood and Marrow Transplant Group centers undertaking autologous transplantation on patients with myeloma and lymphoma and analyze side effects after return of DMSO-preserved stem cells. RESULTS While the majority of centers continue to use 10% DMSO, a significant proportion either use lower concentrations, mostly 5 or 7.5%, or wash cells before infusion (some for selected patients only). In contrast, the median dose of DMSO given (20 mL) was much less than the upper limit set by the same institutions (70 mL). In an accompanying statistical analysis of side effects noted after return of DMSO-preserved stem cells, we show that patients in the highest quartile receiving DMSO (mL and mL/kg body weight) had significantly more side effects attributed to DMSO, although this effect was not observed if DMSO was calculated as mL/min. Dividing the myeloma and lymphoma patients each into two equal groups by age we were able to confirm this result in all but young myeloma patients in whom an inversion of the odds ratio was seen, possibly related to the higher dose of melphalan received by young myeloma patients. CONCLUSION We suggest better standardization of preservation method with reduced DMSO concentration and attention to the dose of DMSO received by patients could help reduce the toxicity and morbidity of the transplant procedure.

Outcome of aplastic anaemia in children. A study by the severe aplastic anaemia and paediatric disease working parties of the European group blood and bone marrow transplant.

This study analysed the outcome of 563 Aplastic Anaemia (AA) children aged 0-12 years reported to the Severe Aplastic Anaemia Working Party database of the European Society for Blood and Marrow Transplantation, according to treatment received. Overall survival (OS) after upfront human leucocyte antigen-matched family donor (MFD) haematopoietic stem cell transplantation (HSCT) or immunosuppressive treatment (IST) was 91% vs. 87% (P 0·18). Event-free survival (EFS) after upfront MFD HSCT or IST was 87% vs. 33% (P 0·001). Ninety-one of 167 patients (55%) failed front-line IST and underwent rescue HSCT. The OS of this rescue group was 83% compared with 91% for upfront MFD HSCT patients and 97% for those who did not fail IST up-front (P 0·017). Rejection was 2% for MFD HSCT and HSCT post-IST failure (P 0·73). Acute graft-versus-host disease (GVHD) grade II-IV was 8% in MFD graft vs. 25% for HSCT post-IST failure (P < 0·0001). Chronic GVHD was 6% in MFD HSCT vs. 20% in HSCT post-IST failure (P < 0·0001). MFD HSCT is an excellent therapy for children with AA. IST has a high failure rate, but remains a reasonable first-line choice if MFD HSCT is not available because high OS enables access to HSCT, which is a very good rescue option.

Current developments in the use of stem cell for therapeutic neovascularisation: is the future therapy "cell-free"?

The plasticity and self-regenerative properties of stem cells have opened new avenues in regenerative medicine. Greater understanding of the biology of stem cells is followed by growing expectations of a rapid translation into alternative therapeutic options. Recent preclinical studies and clinical trials employing stem and progenitor cells from different sources have shown encouraging results. However, their underlying mechanisms are still poorly understood, the potential adverse effects and the discrepancy in efficacy remain to be further investigated. Their essential role in vessel regeneration has made endothelial progenitor cells (EPC) a suitable candidate for therapeutic applications aiming at tissue revascularisation. Recent evidence suggests that EPC contribute to neovascularisation not only by direct participation in tissue homeostasis but mainly via paracrine mechanisms. In future, novel therapeutic strategies could be based on EPC paracrine factors or synthetic factors, and replace cell transplantation.

Interferon-gamma and interleukin-4 mRNA expression by peripheral blood mononuclear cells from pregnant and non-pregnant cattle seropositive for bovine viral diarrhea virus

The acceptance of the fetal allograft by pregnant women and mice seems to be associated with a shift from a Th 1 dominated to a Th 2 dominated immune response to certain infectious agents. The goal of this study was to examine cytokine expression in peripheral blood mononuclear cells (PBMCs) from cattle immune to bovine viral diarrhea virus (BVDV) to determine whether pregnancy also has an influence on the type of immune response in this species. Forty-six heifers and cows between 14 months and 13 years of age were included in this study. Twenty-four were seropositive and 22 seronegative for BVDV. Eleven of the seropositive animals and 11 of the seronegative animals were in the eighth month of gestation, the remaining animals were virgin heifers. PBMC from these animals were analyzed for Interferon (IFN)-gamma and Interleukin (IL)-4 mRNA expression by real-time RT-PCR after stimulation with a non-cytopathic strain of BVDV. Additionally, an ELISA was performed to measure IFN-gamma in the supernatants of stimulated cell cultures. In BVDV seropositive animals, IFN-gamma mRNA levels were significantly higher than in BVDV seronegative animals and there was a significant positive correlation between the changes in IFN-gamma and IL-4 mRNA expression. There was, however, no significant difference in IFN-gamma and IL-4 mRNA levels between pregnant and non-pregnant animals. These results are inconsistent with BVDV inducing a Th1 or Th2 biased immune response. Furthermore, a shift in the cytokine pattern during bovine pregnancy was not evident.

Atypical expression and distribution of embryonic stem cell marker, OCT4, in human lung adenocarcinoma

Lung cancer is one of the leading causes of cancer-related deaths in the world. Although the origin still remains to be resolved, a prevailing hypothesis implies the involvement of cancer stem cells (CSCs) responsible for tumor initiation, maintenance, and progression. Embryonic stem cell marker, OCT4, encoding the spliced variants OCT4A and OCT4B, has recently been shown to have a dual role; as a potential adult stem cell marker and as a CSC marker in germline and somatic tumors.