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Katarina Le Blanc

Publications and source records attributed to Katarina Le Blanc.

At least 19 recordsLinked to original sources
PubMed2006

Concise review: cancer/testis antigens, stem cells, and cancer.

In the multistep process of cancer development, the concept that cancer stem cells are derived from normal stem cells that have gradually accumulated various genetic and epigenetic defects is gaining strong evidence. A number of investigations have identified molecular markers that, under normal conditions, are responsible for stem cell homeostasis but are also expressed in tumor "stem cell-like" subpopulations. In this regard, it was recently reported that a group of tumor-specific antigens known as cancer/testis antigens (CTAs) are expressed in human MSCs. It has long been stated that in normal tissue these antigens are exclusively expressed in germ cell precursors; however, based on these results, we suggest that CTAs are expressed at earlier stages during embryogenesis. The tumor-restricted expression of CTAs has led to several immunotherapeutic trials targeting some of these proteins. The clinical implications that these trials may have on the normal stem cell pools, as well as the immunologic properties of these cells, is to date poorly studied and should be considered.

Antigens, Neoplasm↗
PubMed2006

Mesenchymal stem cells: properties and role in clinical bone marrow transplantation.

Mesenchymal stem cells (MSCs) can be isolated from bone marrow, adipose tissue, cord blood and various fetal tissues. They have the capacity to differentiate into several tissues, including bone, cartilage, tendon, muscle and adipose, and produce growth factors and cytokines that promote hematopoietic cell expansion and differentiation. MSCs also have anti-proliferative, immunomodulatory and anti-inflammatory effects, but only evoke little immune reactivity. In vivo, MSCs prolong skin allograft survival and reverse severe acute graft-versus-host disease. Furthermore, they repair damaged tissue from kidney, heart, liver and gastrointestinal tract. Therefore, in the future, MSCs might have implications for treatment of allograft rejection, graft-versus-host disease, autoimmune inflammatory bowel disease and other disorders in which immunomodulation and tissue repair are required.

Animals↗
PubMed2006

Mesenchymal stem cells for treatment of therapy-resistant graft-versus-host disease.

BACKGROUND: Mesenchymal stem cells (MSC) have immunomodulatory effects. The aim was to study the effect of MSC infusion on graft-versus-host disease (GVHD). METHODS: We gave MSC to eight patients with steroid-refractory grades III-IV GVHD and one who had extensive chronic GVHD. The MSC dose was median 1.0 (range 0.7 to 9)x10(6)/kg. No acute side-effects occurred after the MSC infusions. Six patients were treated once and three patients twice. Two patients received MSC from HLA-identical siblings, six from haplo-identical family donors and four from unrelated mismatched donors. RESULTS: Acute GVHD disappeared completely in six of eight patients. One of these developed cytomegalovirus gastroenteritis. Complete resolution was seen in gut (6), liver (1) and skin (1). Two died soon after MSC treatment with no obvious response. One of them had MSC donor DNA in the colon and a lymph node. Five patients are still alive between 2 months and 3 years after the transplantation. Their survival rate was significantly better than that of 16 patients with steroid-resistant biopsy-proven gastrointestinal GVHD, not treated with MSC during the same period (P = 0.03). One patient treated for extensive chronic GVHD showed a transient response in the liver, but not in the skin and he died of Epstein-Barr virus lymphoma. CONCLUSION: MSC is a very promising treatment for severe steroid-resistant acute GVHD.

Adult↗
PubMed2006

Allogeneic hematopoietic stem cell transplantation for inherited disorders: experience in a single center.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (ASCT) is a possible cure for many inherited disorders. METHODS: We report 20 years of experience in 71 patients. The disorders include 7 immunodeficiencies, 21 hematological disorders, 13 histiocytic disorders, 9 mucopolysaccharoidoses, 7 metachromatic leukodystrophies (MLD), 3 adrenoleukodystrophies (ALD), 2 adrenomyeloneuropathy (AMN), 6 patients with Gaucher's disease, 1 Sandhoff's disease, and 2 patients with aspartylglucosaminuria. Their median age was 4 (0-39) years. The donors were 29 HLA-identical related, 27 matched unrelated (MUD) and 15 HLA mismatches. RESULTS: In recipients of HLA-identical sibling grafts, none developed acute GVHD grades II-IV as against 22% in all others. The overall cumulative incidence of chronic GVHD was 17%. The 5-year survival rates were 93%, 84%, and 46% in recipients of grafts from HLA-identical siblings, MUD and HLA-mismatches, respectively. The overall 10-year survival rate was 69%. All of the surviving patients with immunodeficiencies and hemoglobinopathies are well. Four patients with Hurler's disease are also well, apart from skeletal problems. Five patients with Gaucher's disease are between 14 and 22 years after the transplant. Two infants with MLD deteriorated, a girl with the juvenile form has stable disease and one woman with the adult form has improved. Among four survivors with ALD/AMN, three are well and one has dementia. Two patients with aspartylglucosaminuria have stable disease. CONCLUSION: In patients with inborn errors of metabolism, ASCT gives a high survival rate using HLA-matched donors. Beneficial effects are seen in those who are transplanted early.

Adolescent↗
PubMed2006

The role of HLA mismatch, splenectomy and recipient Epstein-Barr virus seronegativity as risk factors in post-transplant lymphoproliferative disorder following allogeneic hematopoietic stem cell transplantation.

BACKGROUND AND OBJECTIVES: Post-transplant lymphoproliferative disorder (PTLD) following allogeneic hematopioetic stem cell transplantation (HSCT) is a fulminant disease with high mortality. The objective of this study was to determine risk factors in PTLD following HSCT in order to identify high-risk patients for surveillance, prophylaxis and treatment. DESIGN AND METHODS: Five hundred and fifty-three HSCT patients transplanted at Karolinska University Hospital in Huddinge between 1996 and 2004 were investigated retrospectively and 14 cases of PTLD were identified. Diseased patients were evaluated concerning transplantation procedure, PTLD diagnosis, treatment and outcome. Factors significant in univariate analysis were included in logistic regression multivariate analysis. RESULTS: The incidence of PTLD was 2.5% and the median onset of PTLD was 78 days post-transplantation. Only two PTLD patients survived. The most common therapy was anti-B-lymphocyte antibodies. Statistical analysis showed HLA mismatch (p < 0.001), mismatch in Epstein-Barr virus (EBV) serology (p < 0.001) and splenectomy (p = 0.006) to be risk factors associated with PTLD. Indeed, among 387 patients with no risk factors only one developed PTLD (0.26%). Patients with one risk factor had a probability of developing PTLD of 8.2% and those with two risk factors, a probability of 35.7%. INTERPRETATION AND CONCLUSIONS: We propose a strategy for dealing with PTLD. Patients without risk factors need not be monitored routinely. HSCT patients with one or more risk factors should be monitored weekly by polymerase chain reaction of EBV DNA, and for patients with two or more risk factors EBV-specific cytotoxic T-lymphocytes should be held in readiness before initiating the transplantation procedure.

Epstein-Barr Virus Infections↗
PubMed2005

Functional studies of mesenchymal stem cells derived from adult human adipose tissue.

Recent evidence suggests that cells with the properties of human mesenchymal stem cells (hMSCs) can be derived from adult peripheral tissues, including adipose tissue, muscle and dermis. We isolated hMSCs from the stromal-vascular portion of subcutaneous adipose tissue from seven adult subjects. These cells could be readily differentiated into cells of the chondrocyte, osteocyte and adipocyte lineage demonstrating their multipotency. We studied the functional properties of hMSCs-derived adipocytes and compared them with adipocytes differentiated from hMSCs obtained from bone marrow (BM-hMSC). The two cell types displayed similar lipolytic capacity upon stimulation with catecholamines, including a pronounced antilipolytic effect mediated through alpha2A-adrenoceptors, a typical trait in human but not rodent fat cells. Furthermore, both cell types secreted the fat cell-specific factors leptin and adiponectin in comparable amounts per time unit. The fat tissue-derived hMSCs retained their differentiation capacity up to at least fifteen passages. We conclude that hMSCs derived from adult human adipose tissue can be differentiated into fully functional adipocytes with a similar, if not identical, phenotype as that observed in cells derived from BM-hMSCs. Human adipose-tissue-derived MSCs could therefore constitute an efficient and easily obtainable renewable cellular source for studies of adipocyte biology.

Adipocytes↗
PubMed2005

Fetal mesenchymal stem-cell engraftment in bone after in utero transplantation in a patient with severe osteogenesis imperfecta.

BACKGROUND: Mesenchymal stem cells (MSC) are progenitors of mesenchymal tissues such as bone, cartilage, and adipose. Adult human leukocyte antigen (HLA)-matched MSC have been used in cellular therapies of bone disorders such as osteogenesis imperfecta, with promising results. METHODS: A female fetus with multiple intrauterine fractures, diagnosed as severe osteogenesis imperfecta, underwent transplantation with allogeneic HLA-mismatched male fetal MSC in the 32nd week of gestation. Engraftment analyses of donor cells, immunologic reaction against donor cells, and the well-being of the patient were assessed. RESULTS: At 9 months of age, on slides stained for osteocalcin or osteopontin, a centromeric XY-specific probe revealed 0.3% of XY-positive cells in a bone biopsy specimen. Whole Y genome fluorescent in situ hybridization staining showed a median of 7.4% Y-positive cells (range, 6.8%-16.6%). Bone histology showed regularly arranged and configurated bone trabeculae. Patient lymphocyte proliferation against donor MSC was not observed in co-culture experiments performed in vitro after MSC injection. Complementary bisphosphonate treatment was begun at 4 months. During the first 2 years of life, three fractures were noted. At 2 years of corrected age, psychomotor development was normal and growth followed the same channel, -5 SD. CONCLUSIONS: The authors' findings show that allogeneic fetal MSC can engraft and differentiate into bone in a human fetus even when the recipient is immunocompetent and HLA-incompatible.

Adult↗
PubMed2005

Cancer/testis antigen expression in human mesenchymal stem cells: down-regulation of SSX impairs cell migration and matrix metalloproteinase 2 expression.

Several families of genes by and large located on the X chromosome encode proteins of unspecified function. Commonly known as cancer/testis (CT) antigens, they are considered, under normal conditions, only to be expressed in cells of the germ line and placenta. CT genes are also often expressed in cancer cells, hence their classification. Here we report that their expression in normal cells is wider spread and can be observed in cells with the potential for self-renewal and pleuripotency, namely, stem cells. Several CT genes and their products, CT antigens, including SSX, NY-ESO-1, and N-RAGE, were expressed in undifferentiated mesenchymal stem cells (MSCs) and down-regulated after osteocyte and adipocyte differentiation. To elucidate the possible overlapping function played by these genes in cancer and stem cells, a comparative analysis of the localization of their proteins was made. In addition, localization relative to other MSC markers was examined. This revealed that SSX localizes in the cytoplasm and overlap occurs in regions where matrix metalloproteinase 2 (MMP2) and vimentin accumulate. Nevertheless, it was found that no protein interactions between these molecules occur. Further investigation revealed that the migration of a melanoma cell line (DFW), which expresses SSX, MMP2, and vimentin, decreases when SSX is down-regulated. This decrease in cell migration was paralleled by a reduction in MMP2 levels. Analogous to this, SSX expression is down-regulated in MSCs after differentiation; concomitantly a reduction in MMP2 levels occurs. In addition, E-cadherin expression increases, mimicking a mesenchymal epithelial transition. These results afford SSX a functional role in normal stem cell migration and suggest a potentially similar function in cancer cell metastases.

Antigens, Neoplasm↗
PubMed2005

Mesenchymal stem cells inhibit lymphocyte proliferation by mitogens and alloantigens by different mechanisms.

Human mesenchymal stem cells (MSCs) have immuno-modulatory properties. They inhibit T-cell proliferation to mitogens and alloantigens in vitro and prolong skin graft survival in vivo. We found that MSCs inhibited the proliferation of peripheral blood lymphocytes (PBLs) to phorbol myristate acetate (PMA), suggesting that MSCs exert an inhibitory effect downstream of the receptor level. We analyzed cytokine profiles of PBLs co-cultured with MSCs. MSCs increased interleukin (IL)-2 and soluble IL-2 receptor in mixed lymphocyte cultures (MLCs), while IL-2 and IL-2R decreased in phytohemagglutinin (PHA)-stimulated PBL cultures. MSCs inhibited IL-2 induced proliferation, without absorbing IL-2. IL-10 levels increased in MLCs co-cultured with 10% MSCs, while the levels were not affected in PHA cultures. In MLCs inhibited by MSCs, antibodies against IL-10 further suppressed proliferation but had no effect in PHA cultures. Addition of indomethacin, an inhibitor of prostaglandin-synthesis, restored part of the inhibition by MSCs in PHA cultures. However, indomethacin did not affect MSC-induced inhibition in MLCs. To conclude, our data indicate that MSC-induced suppression is a complex mechanism affecting IL-2 and IL-10 signaling and may function differently, depending on T-cell stimuli. Prostaglandins are important in the inhibition by MSCs when the T cells were activated by PHA, but not alloantigens.

Adult↗
PubMed2005

Immunobiology of human mesenchymal stem cells and future use in hematopoietic stem cell transplantation.

Mesenchymal stem cells (MSCs) may be derived from adult bone marrow, fat, and several fetal tissues. In vitro, MSCs can be expanded and have the capacity to differentiate into several mesenchymal tissues, such as bone, cartilage, and fat. They escape the immune system in vitro, and this may make them candidates for cellular therapy in an allogeneic setting. They also have immunomodulatory effects, inhibit T-cell proliferation in mixed lymphocyte cultures, prolong skin allograft survival, and may decrease graft-versus-host disease (GVHD) when cotransplanted with hematopoietic stem cells. MSCs induce their immunosuppressive effect via a soluble factor. Some candidates have been suggested, and various mechanisms have also been suggested, although contradictory data exist; this may be due to differences in the cells and systems tested. A major problem has been that it has been difficult to identify and isolate MSCs after transplantation in vivo. However, MSCs seem to enhance hematopoietic engraftment in recipients of autologous and allogeneic grafts. Recently, they were found to reverse grade IV acute GVHD of the gut and liver. No tolerance was induced, however. Controlled studies are warranted. Thus, in allogeneic stem cell transplantation, MSCs may be used for hematopoiesis enhancement, as GVHD prophylaxis, and for the treatment of severe acute GVHD. They are also of potential use in the treatment of organ transplant rejection and in autoimmune inflammatory bowel disorders where immunomodulation and tissue repair are needed.

Forecasting↗
PubMed2005

Granulocyte and granulocyte-macrophage colony-stimulating factors in allografts: uses, misuses, misconceptions, and future applications.

Despite more than 10 years experience using growth factors after allogeneic stem cell transplantation (ASCT), their state in this has not been elucidated. Most studies show that they accelerate myeloid recovery, regardless of whether they are instituted on day 0 or day 10 after transplant. However, this does not correlate with an improvement in the outcome. One disadvantage is that granulocyte colony-stimulating factor (G-CSF) prophylaxis is associated with slower platelet engraftment due to an increase in platelet aggregation. There is also no agreement as regards the value of G-CSF given as prophylaxis after ASCT, the effects on graft-vs-host disease (GVHD), and the survival rate. A large retrospective study from Europe showed that patients with acute leukemia who received bone marrow from HLA-identical siblings and were treated with G-CSF ran a higher risk of acute and chronic GVHD and transplant-related mortality, while the survival and the leukemia-free survival rates were reduced. In contrast, a meta-analysis of 18 small studies showed no evidence of an increase in acute and chronic GVHD, using G-CSF as prophylaxis after ASCT. Two studies from the Center for International Blood and Marrow Transplant Research showed contradictory data. When G-CSF is given to the recipient as prophylaxis, the levels of soluble interleukin-2 receptor-alpha increase, which aggravates GVHD. When it is given to the donor, G-CSF polarizes T cells to produce T-helper cell-2 cytokines, which reduce GVHD after transplantation. G-CSF has no effect on relapse. Available findings suggest that there is no indication to use G-CSF as prophylaxis after ASCT.

Graft vs Host Disease↗
PubMed2005

Difference in gene expression between human fetal liver and adult bone marrow mesenchymal stem cells.

BACKGROUND AND OBJECTIVES: Mesenchymal stem cells (MSC) are progenitor cells that are capable of differentiating into mesenchymal tissues. Fetal and adult MSC have similar morphology but differ in proliferative, differentiating and immunosuppressive properties. Further exploring their differences could help in choosing the right source for cellular therapy. DESIGN AND METHODS: The gene expression profiles of undifferentiated MSC derived from first trimester fetal liver and adult bone marrow were compared by serial analysis of gene expression, and validated by either reverse transcription polymerase chain reaction or immunoblotting of selected genes. The immunophenotype was compared by flow cytometry and cell ELISA. RESULTS: Seventy genes were differentially induced two-fold or more in fetal MSC compared to adult MSC. These involved transcripts regulating germ plasm and limb patterning, brain and early muscle development. Transcripts implicated in cell cycle promotion, chromatin regulation and DNA repair were also more abundant in fetal MSC. Ninety-seven genes were decreased two-fold or more in fetal MSC, including transcripts involved in smooth muscle and keratinocyte differentiation and transcripts for immunological genes. Although phenotypically largely similar, fetal MSC had a higher expression of ICAM1 and contained intracellular deposits of HLA-G while expression of HLA class I and II molecules and VCAM1 was increased in adult MSC. INTERPRETATION AND CONCLUSIONS: This study reports the first extensive investigation of the differences in gene expression profiles between fetal and adult MSC. The results suggest that fetal MSC have higher proliferative capacity and are less lineage committed than adult MSC.

Adult↗
PubMed2004

A comparison of nonmyeloablative and reduced-intensity conditioning for allogeneic stem-cell transplantation.

BACKGROUND: Nonmyeloablative (NM) conditioning and reduced-intensity conditioning (RIC) are increasingly used for allogeneic hematopoietic stem-cell transplantation. Such regimens have not been compared. METHODS: The primary endpoint was graft-versus-host disease (GVHD). Secondary endpoints included transfusions, engraftment, and transplant-related mortality (TRM). NM conditioning (n=24) consisted of fludarabine and 2-Gy total-body irradiation followed by immunosuppression with cyclosporine A (CsA) combined with mycophenolate mofetil (MMF). The RIC (n=34) protocol consisted of fludarabine combined with busulfan or cyclophosphamide, antithymocyte globulin, and posttransplant immunosuppression CsA plus methotrexate. Diagnoses included hematologic malignancies and solid tumors. Donors were 34 human leukocyte antigen-identical siblings and 24 unrelated donors. Chimerism was analyzed by polymerase chain reaction of minisatellites. RESULTS: Graft failure occurred in 6 of 24 in the NM group and in 1 of 34 in the RIC group, which was a significant difference (odds ratio [OR], 22.6; P=0.02). The NM group also had less leukopenia and required fewer erythrocyte and platelet transfusions than the RIC group. The time to and proportion of CD3, CD19, and CD45 donor chimerism were similar in both groups. The cumulative incidence of grades II to IV acute GVHD was higher in the NM group (59% vs. 12%; OR, 26.9; P<0.001), but we found no difference in the cumulative incidence of chronic GVHD (41% vs. 61%). TRM was 42% in the NM group and 20% in the RIC patients (relative hazard, 11.6; P=0.03). CONCLUSIONS: NM conditioning with posttransplant immunosuppression using CsA and MMF resulted in less leukopenia and fewer transfusions, but resulted in more cases of graft failure, acute GVHD, and TRM than in RIC patients.

Adolescent↗
PubMed2004

Treatment of severe acute graft-versus-host disease with third party haploidentical mesenchymal stem cells.

Adult bone-marrow-derived mesenchymal stem cells are immunosuppressive and prolong the rejection of mismatched skin grafts in animals. We transplanted haploidentical mesenchymal stem cells in a patient with severe treatment-resistant grade IV acute graft-versus-host disease of the gut and liver. Clinical response was striking. The patient is now well after 1 year. We postulate that mesenchymal stem cells have a potent immunosuppressive effect in vivo.

Acute Disease↗
PubMed2004

Immunologic properties of human fetal mesenchymal stem cells.

OBJECTIVE: Mesenchymal stem cells (MSCs) can be isolated from adult bone marrow and fetal liver. We investigated the immunologic properties of undifferentiated and differentiated human fetal MSCs. STUDY DESIGN: Expression of HLA class I and II was investigated by flow cytometry and Western blot on undifferentiated fetal MSC and after in vitro differentiation to adipocytes and osteocytes. Alloreactivity was studied after adding fetal MSCs to allogeneic lymphocytes in mixed lymphocyte cultures. RESULTS: Fetal MSCs expressed HLA class I but not HLA class II. The presence of interferon gamma (IFN-gamma) in the growth medium for 2 days initiated the intracellular synthesis of HLA class II, but 7 days of exposure was required for cell surface expression. Neither undifferentiated nor differentiated fetal MSCs induced proliferation of allogenic lymphocytes. Fetal MSCs treated with IFN-gamma suppressed alloreactive lymphocytes. CONCLUSION: Undifferentiated and differentiated fetal MSCs do not elicit alloreactive lymphocyte proliferation. The results suggest that fetal MSCs have potentials for allogenic transplantation.

Adipocytes↗
PubMed2004

Which donor should be chosen for hematopoietic stem cell transplantation among unrelated HLA-A, -B, and -DRB1 genomically identical volunteers?

The aim of this study was to identify significant prognostic factors by using unrelated genomically HLA-A, -B and -DRB1-identical donors. Such data could help to choose the best donor. We studied 136 consecutive patients with hematologic malignancies and a median age of 32 years (range, 0-55 years) who received hematopoietic stem cell transplantation. Bone marrow grafts were given to 83 and peripheral blood stem cells to 53 patients. The cumulative incidence of grade II to IV acute graft-versus-host disease (GVHD) was 30% and of chronic GVHD was 54%. At 5 years, the overall transplant-related mortality (TRM) was 34%, and patient survival was 50%. In Cox multivariate analysis, 32 potential risk factors were analyzed. Monoclonal antibody OKT-3 during conditioning was correlated with grade II to IV acute GVHD, chronic GVHD, and TRM. HLA-DP mismatch was associated with poor TRM and poor survival. Cytomegalovirus-seropositive patients with a seronegative donor had a decreased leukemia-free survival. Five-year TRM was 14% with no risk factor, 38% with 1 risk factor, and 87% with 2 risk factors. The 5-year survival was 72%, 48%, and 30% with 0, 1, and 2 risk factors, respectively. We concluded that unrelated hematopoietic stem cell transplantation may be improved if an optimal donor and immunosuppression are chosen.

Adolescent↗