Wichard Vogel

Novel Markers for the Prospective Isolation of Human MSC

Abstract:  The isolation of mesenchymal stem cells (MSC) from primary tissue is hampered by the limited selectivity of available markers. So far, CD271 is one of the most specific markers for bone marrow (BM)‐derived MSC. In search of additional markers, monoclonal antibodies (mAbs) with specificity for immature cells were screened by flow cytometry for their specific reactivity with the rare CD271+ population. The recognized CD271+ populations were fractionated by fluorescence‐activated cell sorting and the clonogenic capacity of the sorted cells was analyzed for their ability to give rise to CFU‐F. The results showed that only the CD271bright but not the CD271dim population contained CFU‐F. Two‐color flow cytometry analysis revealed that only the CD271bright population was positive for the established MSC markers CD10, CD13, CD73, and CD105. In addition, a variety of mAbs specific for novel and partially unknown antigens selectively recognized the CD271bright population but no other BM cells. The new MSC‐specific molecules included the platelet‐derived growth factor receptor‐β (CD140b), HER‐2/erbB2 (CD340), frizzled‐9 (CD349), the recently described W8B2 antigen, as well as cell‐surface antigens defined by the antibodies W1C3, W3D5, W4A5, W5C4, W5C5, W7C6, 9A3, 58B1, F9‐3C2F1, and HEK‐3D6. In conclusion, the described markers are suitable for the prospective isolation of highly purified BM‐MSC. These MSC may be used as an improved starting population for transplantation in diseases like osteogenesis imperfecta, cartilage repair, and myocardial infarction.

Expression of MUC-1 Epitopes on Normal Bone Marrow: Implications for the Detection of Micrometastatic Tumor Cells

PURPOSE The expression of the carcinoma-associated mucin MUC-1 is thought to be restricted to epithelial cells and is used for micrometastatic tumor cell detection in patients with solid tumors, including those with breast cancer. Little is known, however, about the expression of MUC-1 epitopes in normal hematopoietic cells. MATERIALS AND METHODS MUC-1 expression was analyzed by flow cytometry and immunocytology on bone marrow (BM) mononuclear cells and purified CD34+ cells from healthy volunteers, using different anti-MUC-1-specific monoclonal antibodies. In addition, Western blotting of MUC-1 proteins was performed. RESULTS Surprisingly, 2% to 10% of normal human BM mononuclear cells expressed MUC-1, as defined by the anti-MUC-1 antibodies BM-2 (2E11), BM-7, 12H12, MAM-6, and HMFG-1. In contrast, two antibodies recognizing the BM-8 and the HMFG-2 epitopes of MUC-1 were not detected. MUC-1+ cells from normal BM consisted primarily of erythroblasts and normoblasts. In agreement with this, normal CD34+ cells cultured in vitro to differentiate into the erythroid lineage showed a strong MUC-1 expression on day 7 proerythroblasts. Western blotting of these cells confirmed that the reactive species is the known high molecular weight MUC-1 protein. CONCLUSION Our data demonstrate that some MUC-1 epitopes are expressed on normal BM cells and particularly on cells of the erythroid lineage. Hence the application of anti-MUC-1 antibodies for disseminated tumor cell detection in BM or peripheral blood progenitor cells may provide false-positive results, and only carefully evaluated anti-MUC-1 antibodies (eg, HMFG-2) might be selected. Furthermore, MUC-1-targeted immunotherapy in cancer patients might be hampered by the suppression of erythropoiesis.

Radioimmunotherapy with yttrium-90-ibritumomab tiuxetan as part of a reduced- intensity conditioning regimen for allogeneic hematopoietic cell transplantation in patients with advanced non-Hodgkin lymphoma: results of a phase 2 study

Forty patients were enrolled in this phase 2 study combining radioimmunotherapy (RIT) using yttrium-90-ibritumomab-tiuxetan (15 MBq [0.4 mCi]/kg) with reduced-intensity conditioning (RIC) using fludarabine (90 mg/m(2)) and 2 Gy total body irradiation followed by allogeneic hematopoietic cell transplantation (HCT) from related (n = 13) or unrelated (n = 27) donors for the treatment of advanced non-Hodgkin lymphoma. Diagnoses were follicular lymphoma (n = 17), chronic lymphocytic leukemia (n = 13), mantle cell lymphoma (n = 8), marginal zone lymphoma (n = 1), and lymphoplasmacytic lymphoma (n = 1). Median age was 55 years (range, 34-68 years). All patients were high risk with refractory disease or relapse after preceding autologous HCT. No additional toxicities attributable to RIT were observed. Engraftment was rapid and sustained. Incidences of acute graft-versus-host disease 2-4 and chronic graft-versus-host disease were 43% and 53%, respectively. Kaplan-Meier-estimated nonrelapse mortality was 45% at 2 years. Twenty-two of 40 patients (55%) are alive, resulting in a Kaplan-Meier-estimated 2-year survival of 51% for all, 67% for follicular lymphoma, 49% for chronic lymphocytic leukemia, and 37% for mantle cell lymphoma patients. The combined use of RIT with RIC is feasible with acceptable toxicity, even in elderly and heavily pretreated patients. This study is registered at www.clinicaltrials.gov as #NCT00302757.

Haploidentical allogeneic hematopoietic cell transplantation in adults using CD3/CD19 depletion and reduced intensity conditioning: a phase II study

Background We report a prospective multicenter phase II study of haploidentical hematopoietic stem cell transplantation using CD3/CD19-depleted grafts after reduced intensity conditioning with fludarabine, thiotepa, melphalan and OKT-3. Design and Methods Sixty-one adults with a median age of 46 years (range 19-65 years) have been enrolled. Diagnoses were acute myeloid leukemia (n=38), acute lymphoblastic leukemia (n=8), non-Hodgkins lymphoma (n=6), myeloma (n=4), chronic myeloid leukemia (n=3), chronic lymphatic leukemia (n=1) and myelodysplastic syndrome (n=1). Patients were considered high risk because of refractory disease (n=18), cytogenetics (n=6), complete remission (≥2) (n=9), chemosensitive relapse in partial remission (n=4) or relapse after prior hematopoietic stem cell transplantation (n=15 allogeneic, n=8 autologous, n=1 both). At haploidentical hematopoietic stem cell transplantation, 30 patients were in complete remission and 31 in partial remission. Grafts contained a median of 7.0×106 (range 3.2-22) CD34+ cells/kg, 4.2×104 (range 0.6-44) CD3+ T cells/kg and 2.7×107 (range 0.00-37.3) CD56+ cells/kg. Results Engraftment was rapid with a median of 12 days to granulocytes more than 0.5×109/L (range 9-50 days) and 11 days to platelets more than 20×109 (range 7-38 days). Incidence of grade IIIV acute graft-versus-host-disease and chronic graft-versus-host-disease was 46% and 18%, respectively. Non-relapse mortality on Day 100 was 23% and 42% at two years. Cumulative incidence of relapse/progression at two years was 31%. Kaplan-Meier estimated 1-year and 2-year overall survival with median follow up of 869 days (range 181-1932) is 41% and 28%, respectively. Conclusions This regimen allows successful haploidentical hematopoietic stem cell transplantation with reduced intensity conditioning in high-risk patients lacking a suitable donor. (clinicaltrials.gov identifier:NCT00202917).

Clinical Applications of CD34+ Peripheral Blood Progenitor Cells (PBPC)

Recently, a number of devices have been developed for the positive selection of CD34+ peripheral blood progenitor cells (PBPC) for clinical use in autologous or allogeneic transplantation. The rationale for CD34+ selection is based on clinical studies showing a two‐ to five‐log reduction of contaminating tumor cells in patients with breast cancer, multiple myeloma and low‐grade lymphoma. In addition, a three‐ to five‐log reduction of T cells can be obtained by CD34+ selection in both autologous grafts for patients with autoimmune disease resistant to conventional therapy and allogeneic grafts to reduce the incidence and severity of acute graft‐versus‐host disease.

Optimization of Autologous Stem Cell Transplantation for Systemic Sclerosis — A Single-center Longterm Experience in 26 Patients with Severe Organ Manifestations

Objective. Autologous stem cell transplantation (aSCT) for systemic sclerosis (SSc) has been shown to be effective in recent reports. This aggressive approach and the disease itself are associated with a high mortality. We report our experiences in 26 consecutive patients. Methods. Between 1997 and 2009, 26 patients were scheduled for aSCT. Our standard transplant regimen consists of cyclophosphamide (CYC) and granulocyte colony-stimulating factor (GCSF) for mobilization and CYC plus antithymocyte globulin for conditioning before the retransfusion of CD34 selected stem cells. The major outcome variable was the response to treatment [reduction of modified Rodnan skin score (mRSS) by 25%] at Month 6. Secondary endpoints were the transplant-related mortality and the progression-free survival. Results. Significant skin and lung function improvement of the mRSS was achieved in 78.3% of patients at Month 6. The overall response rate was 91%, as some patients improved even after Month 6. Three patients died between mobilization and conditioning treatment, 2 due to severe disease progression and 1 whose death was considered treatment-related (i.e., GCSF or CYC toxicity). Depending on definitions, transplant-related mortality was 4% and treatment-related mortality 11%. Seven patients experienced a relapse during the 4.4 years of followup. The progression-free survival was 74%. Four patients died during followup and the most frequent causes of death were pulmonary and cardiac complications of SSc. Conclusion. aSCT led to significant improvement in most patients with SSc. The procedure requires further optimization; hence we are modifying our screening and treatment strategy. To minimize infectious complications, CYC for mobilization and GCSF were reduced. We intensified our screening for cardiac involvement and modified our conditioning regimen in case of cardiac involvement.

Monoclonal antibody 9C4 recognizes epithelial cellular adhesion molecule, a cell surface antigen expressed in early steps of erythropoiesis.

OBJECTIVE Monoclonal antibody (mAb) 9C4 detects a surface antigen expressed on immature erythroid progenitor cells and epithelial tumor cell lines. The aim of this study was to identify the recognized surface antigen and to analyze a potential role of this molecule in early steps of erythropoiesis. MATERIALS AND METHODS A pituitary-derived retroviral cDNA library was used to generate viruses and infect NIH-3T3 fibroblasts. The transfected cells were stained with mAb 9C4; positive cells were sorted by FACS; and a clonal cell line binding mAb 9C4 was established. cDNA encoding the 9C4-binding protein was amplified by polymerase chain reaction and cloned. Reactivity of mAb 9C4 with human bone marrow (BM) cells was analyzed by flow cytometry. RESULTS Sequence analysis of the isolated cDNA uncovered a 100% identity with the epithelial cellular adhesion molecule (Ep-CAM). Two-color flow cytometric analysis revealed that almost 100% of Ep-CAM(+) BM cells coexpressed CD105, E-cadherin, and high levels of CD71. Fractions of Ep-CAM(+) BM cells also were CD34(+) but lacked glycophorin A expression, suggesting that Ep-CAM(+) cells represent immature erythroid cells. Reverse transcriptase polymerase chain reaction analysis of BM mononuclear cells revealed that the 9C4(+) erythroblast population but not the 9C4(-) fraction expressed Ep-CAM mRNA. Peripheral blood CD34(+) cells induced in vitro to differentiate into the erythroid lineage showed strong Ep-CAM expression on days 3 to 7 of culture. The addition of Ep-CAM-specific mAbs 9C4 or KS1/4 to the culture resulted in two- to three-fold up-regulation of Ep-CAM protein expression. CONCLUSION mAb 9C4 recognizes Ep-CAM, a molecule expressed in the early steps of erythropoiesis.

Radiologic Spectrum of Extramedullary Relapse of Myelogenous Leukemia in Adults

OBJECTIVE Chloroma, also know as granulocytic sarcoma, is a localized extramedullary tumor composed of malignant cells of the myeloid cell line. It occurs most frequently secondary to a history of myelogenous leukemia as extramedullary relapse. New treatment regimens, including allogeneic stem cell transplantation, extensive use of donor lymphocyte infusion, and second transplantation, are associated with increased rates of chloroma of up to 21%. The purpose of this article is to highlight the sites of involvement as well as the morphologic and imaging features of chloroma in patients with myelogenous leukemia. CONCLUSION Allogeneic stem cell transplantation now represents the treatment of choice for leukemia and for patients with leukemia relapse. Therefore, the rate of chloroma is likely to increase. Because clinical and laboratory data are frequently not indicative, radiologic diagnosis of chloroma will become more important.

Analysis of a long-term outbreak of XDR Pseudomonas aeruginosa: a molecular epidemiological study

OBJECTIVES Here we report on a long-term outbreak from 2009 to 2012 with an XDR Pseudomonas aeruginosa on two wards at a university hospital in southern Germany. METHODS Whole-genome sequencing was performed on the outbreak isolates and a core genome was constructed for molecular epidemiological analysis. We applied a time-place-sequence algorithm to improve estimation of transmission probabilities. RESULTS By using conventional infection control methods we identified 49 P. aeruginosa strains, including eight environmental isolates that belonged to ST308 (by MLST) and carried the metallo-β-lactamase IMP-8. Phylogenetic analysis on the basis of a non-recombinant core genome that contained 22 outbreak-specific SNPs revealed a pattern of four dominant clades with a strong phylogeographic structure and allowed us to determine the potential temporal origin of the outbreak to July 2008, 1 year before the index case was diagnosed. Superspreaders at the root of clades exhibited a high number of probable and predicted transmissions, indicating their exceptional position in the outbreak. CONCLUSIONS Our results suggest that the initial expansion of dominant sublineages was driven by a few superspreaders, while environmental contamination seemed to sustain the outbreak for a long period despite regular environmental control measures.

Determination of residual T- and B-cell content after immunomagnetic depletion: proposal for flow cytometric analysis and results from 103 separations

BACKGROUND T- and B-cell depletion of apheresis products is an attractive alternative to standard stem cell enrichment in haplo-identical transplantation. Thorough T- and B-cell depletion is necessary for prevention of acute GvHD and T-cell depletion-associated lymphoproliferative disorders. However, the large number of non-T and -B cells in the graft requires special protocols for the determination of extremely low frequencies of residual T cells. METHODS Apheresis products from healthy donors were T- and B-cell depleted by the CliniMACS system using CD3 and CD19 Ab reagents and the LS tubing set. The recovery of cells and degree of depletion were determined. A four-color multigating strategy was used for enumeration of residual T and B cells. RESULTS One-hundred and three separations were performed, with a mean cell recovery of 38+/-12%, CD34 recovery of 61+/-16% and CD56 recovery of 63+/-33%. T and B cells were depleted by log 4.15+/-0.46 and log 3.64+/-0.63, respectively. Four-color multigating flow cytometry allowed the detection of single T cells. DISCUSSION Combined T- and B-cell depletion is a feasible method for obtaining stem cell grafts with acceptable stem cell recovery, profound T- and B-cell depletion and a very high amount of NK cells and monocytes. However, analysis of residual T cells is challenging and requires special protocols.