Bone Marrow Research The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Bone Marrow Vascular Niche: Home for Hematopoietic Stem Cells Mon, 14 Apr 2014 08:12:38 +0000 Though discovered later than osteoblastic niche, vascular niche has been regarded as an alternative indispensable niche operating regulation on hematopoietic stem cells (HSCs). As significant progresses gained on this type niche, it is gradually clear that the main work of vascular niche is undertaking to support hematopoiesis. However, compared to what have been defined in the mechanisms through which the osteoblastic niche regulates hematopoiesis, we know less in vascular niche. In this review, based on research data hitherto we will focus on component foundation and various functions of vascular niche that guarantee the normal hematopoiesis process within bone marrow microenvironments. And the possible pathways raised by various research results through which this environment undergoes its function will be discussed as well. Ningning He, Lu Zhang, Jian Cui, and Zongjin Li Copyright © 2014 Ningning He et al. All rights reserved. Hepatitis C among Egyptian Patients Referred for Bone Marrow Examination: Seroprevalence and Analysis of Hematological Findings Thu, 10 Apr 2014 08:30:43 +0000 Hepatitis C is a significant public health problem in Egypt where the highest prevalence (14.7%) of hepatitis C virus (HCV) exists. HCV prevalence is even higher among clinical populations and groups at risk of exposure to infection. Chronic HCV infection is associated with several hematological complications that may necessitate bone marrow (BM) examination. The aim of this study is to estimate HCV prevalence among patients referred for BM examination and to explore hematological and BM findings among HCV positive patients. One hundred adult patients referred for BM examination were included in the study and screened for HCV antibodies. Patients’ clinical, hematological, and BM findings were recorded. The seroprevalence of HCV among patients referred for BM examination was 42%. The most common indication for BM examination among HCV positive patients was peripheral cytopenias (88.1%). The most common cytopenia detected was thrombocytopenia (85.7%). The most common diagnosis among HCV positive patients was hypersplenism (52.4%) followed by B-lymphoproliferative disorders (19%) and then immune thrombocytopenic purpura (11.9%). In conclusion, HCV prevalence among patients referred for BM examination is higher than that estimated in the general population. Patients with unexplained peripheral cytopenias should be tested for HCV. Somaia Mohammed Mousa Copyright © 2014 Somaia Mohammed Mousa. All rights reserved. Combination of Complement-Dependent Cytotoxicity and Relative Fluorescent Quantification of HLA Length Polymorphisms Facilitates the Detection of a Loss of Heterozygosity Thu, 03 Apr 2014 13:35:09 +0000 Loss of heterozygosity (LOH) is a common event in malignant cells. In this work we introduce a new approach to identify patients with loss of heterozygosity in the HLA region either at first diagnosis or after HLA mismatched allogeneic HSCT. Diagnosis of LOH requires a high purity of recipient target cells. FACS is time consuming and also frequently prevented by rather nonspecific or unknown immune phenotype. The approach for recipient cell enrichment is based on HLA targeted complement-dependent cytotoxicity (CDC). Relative fluorescent quantification (RFQ) analysis of HLA intron length polymorphisms then allows analysis of HLA heterozygosity. The approach is exemplified in recent clinical cases illustrating the detection of an acquired allele loss. As illustrated in one case with DPB1, distinct HLA loci in donor and patient were sufficient for both proof of donor cell removal and evaluation of allele loss in the patient's leukemic cells. Results were confirmed using HLA-B RFQ analysis and leukemia-associated aberrant immunophenotype (LAIP) based cell sort. Both results confirmed suspected loss of HLA heterozygosity. Our approach complements or substitutes for FACS-based cell enrichment; hence it may be further developed as novel routine diagnostic tool. This allows rapid recipient cell purification and testing for loss of HLA heterozygosity before and after allogeneic HSCT in easily accessible peripheral blood samples. Klaus Witter, Roland Reibke, Marion Subklewe, Robert Zahn, Teresa Kauke, Karsten Spiekermann, Michael Spannagl, Johanna Tischer, Wolfgang Hiddemann, and Andrea Dick Copyright © 2014 Klaus Witter et al. All rights reserved. Angiogenesis and Proliferation Index in Patients with Acute Leukemia: A Prospective Study Mon, 31 Mar 2014 11:59:10 +0000 Angiogenesis and proliferation as measured by microvessel density (MVD) and proliferation index (PI) are essential correlates of malignancy. The aim of our study was to evaluate difference between these values in AML and ALL and also to study the modulation in these parameters following achievement of remission in acute lymphoblastic leukemia. Differences between adult and adolescent cases of acute leukemia in relation to these values were also studied. We also tried to assess the relationship between angiogenesis and proliferation. Fifty-five patients with acute leukemia were included in the study. Trephine biopsies were immunostained with CD34 and factor VIIIrAg to demonstrate angiogenesis measured as MVD. Immunostaining with PCNA and Ki-67 was done to study proliferation. We found a significant increase in MVD and PI in cases when compared with controls (). In addition cases with ALL had a significantly higher MVD compared to those with AML (). The patients with ALL who went into remission showed a significant reduction in MVD; PI remained high. The cases which did not achieve remission showed no significant reduction in either MVD or PI. All adolescent cases of ALL were similar to adults with respect to MVD and PI. Prabhavati Jothilingam, Debdatta Basu, and Tarun K. Dutta Copyright © 2014 Prabhavati Jothilingam et al. All rights reserved. Myelonecrosis: A Clinicopathological Study from a Tertiary Care Center in South India over a Twelve-Year Period Thu, 23 Jan 2014 12:40:25 +0000 Aims. To study the etiology, diagnostic features, and clinical significance of myelonecrosis. Methods. A retrospective review of all trephine biopsies done over 12 years (January 2000 to December 2012) in Department of pathology was done and all trephine biopsies showing MN were identified and studied. Results. Twenty-five cases accounting for 0.4% were identified. Fever and generalized weakness were the common presenting symptoms. Anemia was seen in all cases followed by thrombocytopaenia. Malignancy was the underlying cause in 64% of cases; hematolymphoid malignancy was seen in two-thirds and solid malignancies in one-third of the cases. Tuberculosis accounted for 16% of the cases and the etiology was unknown in 12%. Conclusions. The causes of MN are varied and hematological malignancy and solid malignancies are the most common causes. Presence of myelonecrosis is associated with a poor prognosis. Myelonecrosis may obscure the underlying disorder and hence a thorough search in the bone marrow biopsy itself with the help of immunohistochemistry may prove worthwhile in identifying the underlying disease. Jinkala Sree Rekha, Rakhee Kar, and Debdatta Basu Copyright © 2014 Jinkala Sree Rekha et al. All rights reserved. Validation of the EBMT Risk Score for South Brazilian Patients Submitted to Allogeneic Hematopoietic Stem Cell Transplantation Thu, 12 Dec 2013 15:25:36 +0000 Background. Allogeneic hematopoietic stem cell transplantation (HSCT) is still associated with a high transplant-related mortality rate. In 2009, the EBMT risk score was validated as a simple tool to predict the outcome after allogeneic HSCT for acquired hematological disorders. Objectives. The aim of this study was to validate the applicability of the EBMT risk score for allogeneic HSCT on South Brazilian patients. Methods. A retrospective observational study was performed based on patients' records and data base at Hospital de Clínicas de Porto Alegre, including all allogeneic transplants for malignant and severe aplastic anemia from 1994 to 2010. Patients were categorized according to EBMT risk score and overall survival (OS). Nonrelapse mortality (NRM) and relapse rate (RR) were analyzed. Results. There were 278 evaluable patients. OS, NRM, and RR at five years median followup were 48.7%, 40.7%, and 30.7%, respectively. The OS was 81.8% for risk score 0 and 0% for score 6 (), and NRM was 13.6% and 80% for risk scores 0 and 6, respectively (). Conclusion. The EBMT risk score can be utilized as a tool for clinical decision making before allogeneic HSCT for malignant hematological diseases and severe aplastic anemia at a single center in Brazil. Beatriz Stela Pitombeira, Alessandra Paz, Annelise Pezzi, Bruna Amorin, Vanessa Valim, Alvaro Laureano, Andrea Wieck, Lisandra Rigoni, Érica Ottoni, Gustavo Fisher, Liane Daudt, and Lucia Silla Copyright © 2013 Beatriz Stela Pitombeira et al. All rights reserved. The Role of miRNA in Haematological Malignancy Thu, 12 Dec 2013 15:02:19 +0000 Currently, there are over 1,800 annotated human miRNAs, many of which have tissue-specific expression. Numerous studies have highlighted their role in haematopoietic differentiation and proliferation, acting as master regulators of haematopoietic stem cell function. Aberrant expression of miRNAs has been observed in haematological cancers, exhibiting unique expression signatures in comparison to normal counterparts. Functional and target analyses as well as animal models have attempted to annotate how different miRNA may contribute to the pathophysiology of these malignancies from modulating cancer associated genes, functioning directly as oncogenes or tumour suppressor genes or acting as bystanders or regulators of the epigenetic mechanisms in cancer. miRNAs have also been shown to play a role in modulating drug resistance and determining prognosis between the various subtypes of blood cancers. This review discusses the important role that miRNAs play in haematological malignancies by exploring associations that exist between the two and trying to examine evidence of causality to support the tantalising possibility that miRNAs might serve as therapeutic targets in blood cancers. Stephanie Gounaris-Shannon and Timothy Chevassut Copyright © 2013 Stephanie Gounaris-Shannon and Timothy Chevassut. All rights reserved. Human Mesenchymal Stromal Cell-Mediated Immunoregulation: Mechanisms of Action and Clinical Applications Sun, 29 Sep 2013 09:41:27 +0000 Mesenchymal stromal cells (MSCs) are multipotent cells found in connective tissues that can differentiate into bone, cartilage, and adipose tissue. Interestingly, they can regulate immune responses in a paracrine way and allogeneic MSCs do not elicit immune response. These properties have encouraged a number of clinical trials in a broad range of regenerative therapies. Although these trials were first focused on their differentiation properties, in the last years, the immunosuppressive features have gained most of the attention. In this review, we will summarize the up-to-date knowledge about the immunosuppressive mechanisms of MSCs in vivo and in vitro and the most promising approaches in clinical investigation. Akaitz Dorronsoro, Jon Fernández-Rueda, Karoline Fechter, Izaskun Ferrin, Juan Manuel Salcedo, Emma Jakobsson, and César Trigueros Copyright © 2013 Akaitz Dorronsoro et al. All rights reserved. Day 100 Peripheral Blood Absolute Lymphocyte/Monocyte Ratio and Survival in Classical Hodgkin's Lymphoma Postautologous Peripheral Blood Hematopoietic Stem Cell Transplantation Sun, 28 Apr 2013 16:29:39 +0000 Day 100 prognostic factors of postautologous peripheral blood hematopoietic stem cell transplantation (APBHSCT) to predict clinical outcome in classical Hodgkin lymphoma (cHL) patients have not been evaluated. Thus, we studied if the day 100 peripheral blood absolute lymphocyte/monocyte ratio (Day 100 ALC/AMC) affects clinical outcomes by landmark analysis from day 100 post-APBHSCT. Only cHL patients achieving a complete remission at day 100 post-APBHSCT were studied. From 2000 to 2010, 131 cHL consecutive patients qualified for the study. The median followup from day 100 was 4.1 years (range: 0.2–12.3 years). Patients with a Day 100 ALC/AMC ≥ 1.3 experienced superior overall survival (OS) and progression-free survival (PFS) compared with Day 100 ALC/AMC < 1.3 (from day 100: OS, median not reached versus 2.8 years; 5 years OS rates of 93% (95% CI, 83%–97%) versus 35% (95% CI, 19%–51%), resp., ; from day 100: PFS, median not reached versus 1.2 years; 5 years PFS rates of 79% (95% CI, 69%–86%) versus 27% (95% CI, 14%–45%), resp., ). Day ALC/AMC ratio was an independent predictor for OS and PFS. Thus, Day 100 ALC/AMC ratio is a simple biomarker that can help to assess clinical outcomes from day 100 post-APBHSCT in cHL patients. Luis F. Porrata, David J. Inwards, Stephen M. Ansell, Ivana N. Micallef, Patrick B. Johnston, William J. Hogan, and Svetomir N. Markovic Copyright © 2013 Luis F. Porrata et al. All rights reserved. Incidence and Pattern of Graft-versus-Host Disease in Patients Undergoing Allogeneic Transplantation after Nonmyeloablative Conditioning with Total Lymphoid Irradiation and Antithymocyte Globulin Wed, 17 Apr 2013 18:32:07 +0000 Nonmyeloablative (NMA) conditioning with total lymphoid irradiation and antithymocyte globulin (TLI/ATG) has been shown to protect against acute graft-versus-host disease (GVHD). We report here our institutional experience with allogeneic transplantation following NMA conditioning with TLI/ATG (). GVHD prophylaxis consisted of a combination of a calcineurin inhibitor and mycophenolate mofetil. Median patient age was 59 years. The median followup of surviving patients is 545 days. One patient experienced primary graft rejection. The median time to neutrophil engraftment was 18 days and platelet engraftment was 9.5 days. The cumulative incidence (CI) of grade II–IV acute GVHD at day +100 was 28.6% and 38.1% at day +180. The CI for grade III-IV acute GVHD was 28.6% at day +180. CI of chronic GVHD was 45.2% at 1 year. The CI of disease relapse was 9.5% at 1 year. The rate of nonrelapse mortality (NRM) was 0% at day +100 and only 9.5% at 1 year. The overall and progression free survival at 1 year was 81% and 80.4%, respectively. Our limited, retrospective data show encouraging relapse and NRM rates with TLI/ATG-based NMA conditioning, but with higher than previously reported rates of acute and chronic GVHD, underscoring the need for novel strategies designed to effectively prevent GVHD. Lauren Veltri, Michael Regier, Aaron Cumpston, Sonia Leadmon, William Tse, Michael Craig, and Mehdi Hamadani Copyright © 2013 Lauren Veltri et al. All rights reserved. High-Frequency Vibration Treatment of Human Bone Marrow Stromal Cells Increases Differentiation toward Bone Tissue Mon, 25 Mar 2013 10:08:55 +0000 In order to verify whether differentiation of adult stem cells toward bone tissue is promoted by high-frequency vibration (HFV), bone marrow stromal cells (BMSCs) were mechanically stimulated with HFV (30 Hz) for 45 minutes a day for 21 or 40 days. Cells were seeded in osteogenic medium, which enhances differentiation towards bone tissue. The effects of the mechanical treatment on differentiation were measured by Alizarin Red test, (q) real-time PCR, and protein content of the extracellular matrix. In addition, we analyzed the proliferation rate and apoptosis of BMSC subjected to mechanical stimulation. A strong increase in all parameters characterizing differentiation was observed. Deposition of calcium was almost double in the treated samples; the expression of genes involved in later differentiation was significantly increased and protein content was higher for all osteogenic proteins. Lastly, proliferation results indicated that stimulated BMSCs have a decreased growth rate in comparison with controls, but both treated and untreated cells do not enter the apoptosis process. These findings could reduce the gap between research and clinical application for bone substitutes derived from patient cells by improving the differentiation protocol for autologous cells and a further implant of the bone graft into the patient. D. Prè, G. Ceccarelli, L. Visai, L. Benedetti, M. Imbriani, M. G. Cusella De Angelis, and G. Magenes Copyright © 2013 D. Prè et al. All rights reserved. Adenoviral Delivery of the VEGF and BMP-6 Genes to Rat Mesenchymal Stem Cells Potentiates Osteogenesis Tue, 26 Feb 2013 14:17:32 +0000 The combined delivery of mesenchymal stem cells (MSCs), vascular endothelial growth factor (VEGF), and bone morphogenetic protein (BMP) to sites of bone injury results in enhanced repair compared to the administration of a single factor or a combination of two factors. Based on these findings, we hypothesized that coexpression of VEGF and BMP-6 genes would enhance the osteoblastic differentiation of rat bone-marrow-derived stem cells (rMSCs) and osteogenesis by comparison to rMSCs that do not express VEGF and BMP-6. We prepared a GFP tagged adenovirus vector (Ad-VEGF+BMP-6) that contained DNA encoding the hVEGF and hBMP-6 genes. rMSCs were transduced with the virus, and the successful transduction was confirmed by green fluorescence and by production of VEGF and BMP-6 proteins. The cells were cultured to assess osteoblastic differentiation or administered in the Fischer 344 rats to assess bone formation. Mineralization of rMSCs transduced with Ad-VEGF+BMP-6 was significantly enhanced over the nontransduced rMSCs. Only transduced rMSCs could induce osteogenesis in vivo, whereas Ad-VEGF+BMP-6 or nontransduced rMSCs alone did not induce osteogenesis. The data suggests that the combined delivery of MSCs, VEGF, and BMP-6 is an attractive option for bone repair therapy. Jesse Seamon, Xiuli Wang, Fuai Cui, Tom Keller, Abhijit S. Dighe, Gary Balian, and Quanjun Cui Copyright © 2013 Jesse Seamon et al. All rights reserved. Biological and Genetic Aspects of Donor-Recipient Matching in HSCT Sun, 09 Dec 2012 11:27:47 +0000 Andrzej Lange, Colette Raffoux, and Bronwen Shaw Copyright © 2012 Andrzej Lange et al. All rights reserved. Improving Safety of Preemptive Therapy with Oral Valganciclovir for Cytomegalovirus Infection after Allogeneic Hematopoietic Stem Cell Transplantation Mon, 03 Dec 2012 16:10:48 +0000 Valganciclovir (VGC), an oral prodrug of ganciclovir (GCV), has been shown to clear cytomegalovirus (CMV) viremia in preemptive treatment of patients after allogeneic hematopoietic stem cell transplantation (alloHSCT), apparently without significant toxicity. Since VGC obviates hospitalization, it is increasingly being adopted, although not approved, in alloHSCT. When we retrospectively evaluated preemptive treatment with VGC versus GCV, foscarnet or cidofovir, in all 312 consecutive CMV viremias of 169 patients allotransplanted at our institution between 1996 and 2006, we found VGC more efficacious (79%) than non-VGC therapies (69%). The advantage of outpatient VGC, however, was outbalanced by more profound neutropenias (including two cases of agranulocytosis, one with graft loss) requiring subsequent prolonged rehospitalization. Thus, in a second, prospective cohort from 2007 to 2011 (all 202 consecutive CMV viremias of 118 yet older and sicker patients), we implemented twice weekly neutrophil monitoring during outpatient VGC treatment and avoided VGC maintenance therapy. While conserving efficacy (VGC 71%, non-VGC 72%), we could now demonstrate a reduced mean duration of hospitalization with VGC (9 days (0–66)) compared to non-VGC (25 days (0–115)), without any agranulocytosis episodes. We conclude that safe outpatient VGC therapy is possible in alloHSCT recipients, but requires frequent monitoring to prevent severe myelotoxicity. Corinna Barkam, Haytham Kamal, Elke Dammann, Helmut Diedrich, Stefanie Buchholz, Matthias Eder, Jürgen Krauter, Arnold Ganser, and Michael Stadler Copyright © 2012 Corinna Barkam et al. All rights reserved. New Rising Infection: Human Herpesvirus 6 Is Frequent in Myeloma Patients Undergoing Autologous Stem Cell Transplantation after Induction Therapy with Bortezomib Thu, 29 Nov 2012 08:22:06 +0000 Herpesvirus 6 (HHV-6) infection is a common complication during immunosuppression. Its significance for multiple myeloma (MM) patients undergoing autologous stem cell transplantation (ASCT) after treatment with novel agents affecting immune system remains undetermined. Data on 62 consecutive MM patients receiving bortezomib-dexamethasone (VD) (; 66%) or thalidomide-dexamethasone (TD) (, 34%) induction, together with melphalan 200 mg/m2 autograft between 01.2005 and 09.2010, were reviewed. HHV-6 reactivation was diagnosed in patients experiencing postengraftment unexplained fever (PEUF) in the presence of any level of HHHV-6 DNA in blood. There were no statistically significant differences in patient characteristics between the groups, excluding dexamethasone dosage, which was significantly higher in patients receiving TD. Eight patients in TD and 18 in VD cohorts underwent viral screening for PEUF. HHV-6 reactivation was diagnosed in 10 patients of the entire series (16%), accounting for 35% of those screened; its incidence was 19.5% () in the VD group versus 9.5% () in the TD group. All patients recovered without sequelae. In conclusion, HHV-6 reactivation is relatively common after ASCT, accounting for at least a third of PEUF episodes. Further studies are warranted to investigate whether bortezomib has an impact on HHV-6 reactivation development. Netanel Horowitz, Ilana Oren, Noa Lavi, Tsila Zuckerman, Noam Benyamini, Zipi Kra-Oz, Viki Held, and Irit Avivi Copyright © 2012 Netanel Horowitz et al. All rights reserved. Differential Expression of Matrix Metalloproteinase-2 Expression in Disseminated Tumor Cells and Micrometastasis in Bone Marrow of Patients with Nonmetastatic and Metastatic Prostate Cancer: Theoretical Considerations and Clinical Implications—An Immunocytochemical Study Mon, 26 Nov 2012 15:55:14 +0000 Matrix metalloproteinase-2 (MMP-2) is important in the dissemination and invasion of tumor cells and activates angiogenesis. We present an immunocytochemical study of MMP-2 expression in circulating prostate cells (CPCs), disseminated tumor cells (DTCs), and micrometastasis (mM) in bone marrow of men with prostate cancer. Methods and Patients. Tumor cells were identified with anti-PSA immunocytochemistry. Positive samples underwent processing with anti-MMP-2, its expression was compared with Gleason score, concordance of expression, and metastatic and nonmetastatic disease. Results. 215 men participated, CPCs were detected in 62.7%, DTCs in 62.2%, and mM in 71.4% in nonmetastatic cancer; in metastatic cancer all had CPCs, DTCs, and mM detected. All CPCs and DTCs expressed MMP-2; in mM MMP-2 expression was positively associated with increasing Gleason score. MMP-2 expression in CPCs and DTCs showed concordance. In low grade tumors, mM and surrounding stromal cells were MMP-2 negative, with variable expression in high grade tumors; in metastatic disease, both mM and stromal cells were MMP-2 positive. Conclusions. CPCs and DTCs are different from mM, with inhibition of MMP-2 expression in mM of low grade tumors. With disease progression, MMP-2 expression increases in both mM and surrounding stromal cells, with implications for the use of bisphosphonates or MMP-2 inhibitors. Nigel P. Murray, Eduardo Reyes, Pablo Tapia, Leonardo Badínez, and Nelson Orellana Copyright © 2012 Nigel P. Murray et al. All rights reserved. CMV Serostatus of Donor-Recipient Pairs Influences the Risk of CMV Infection/Reactivation in HSCT Patients Thu, 22 Nov 2012 12:31:51 +0000 CMV donor/recipient serostatus was analyzed in 200 patients allografted in our institution from unrelated (122 patients) donors and 78 sibling donors in the years 2002–2011 in relation to posttransplant complications. On a group basis independently of the CMV serostatus of donor-recipient pairs sibling transplantations and those from unrelated donors that matched 10/10 at allele level had a similar rate of CMV reactivation (17/78 versus 19/71, ). The rate of CMV reactivation/infection was higher in patients grafted from donors accepted at the lower level of matching than 10/10 (18/38 versus 36/149, ). The incidence of aGvHD followed frequencies of CMV reactivation in the tested groups, being 40/156 and 25/44 in patients grafted from sibling or unrelated donors that 10/10 matched and in those grafted from donors taht HLA mismatched, respectively (). Regarding the rate of reactivation in both groups seropositive patients receiving a transplant from seronegative donors had more frequently CMV reactivation as compared to those with another donor-recipient matching CMV serostatus constellation (22/43 versus 32/143, ). Multivariate analysis revealed that seropositivity of recipients with concomitant seronegativity of donors plays an independent role in the CMV reactivation/infection (, ; , ; , for optimally matched and mismatched patients and the whole group of patients, resp.). Emilia Jaskula, Jolanta Bochenska, Edyta Kocwin, Agnieszka Tarnowska, and Andrzej Lange Copyright © 2012 Emilia Jaskula et al. All rights reserved. Human Leukocyte Antigen Profiles of Latin American Populations: Differential Admixture and Its Potential Impact on Hematopoietic Stem Cell Transplantation Sun, 18 Nov 2012 15:03:38 +0000 The outcome of hematopoietic stem cell transplantation (HSCT) is shaped by both clinical and genetic factors that determine its success. Genetic factors including human leukocyte antigen (HLA) and non-HLA genetic variants are believed to influence the risk of potentially fatal complications after the transplant. Moreover, ethnicity has been proposed as a factor modifying the risk of graft-versus-host disease. The populations of Latin America are a complex array of different admixture processes with varying degrees of ancestral population proportions that came in different migration waves. This complexity makes the study of genetic risks in this region complicated unless the extent of this variation is thoroughly characterized. In this study we compared the HLA-A and HLA-B allele group profiles for 31 Latin American populations and 61 ancestral populations from Iberia, Italy, Sub-Saharan Africa, and America. Results from population genetics comparisons show a wide variation in the HLA profiles from the Latin American populations that correlate with different admixture proportions. Populations in Latin America seem to be organized in at least three groups with (1) strong Amerindian admixture, (2) strong Caucasian component, and (3) a Caucasian-African gradient. These results imply that genetic risk assessment for HSCT in Latin America has to be adapted for different population subgroups rather than as a pan-Hispanic/Latino analysis. Esteban Arrieta-Bolaños, J. Alejandro Madrigal, and Bronwen E. Shaw Copyright © 2012 Esteban Arrieta-Bolaños et al. All rights reserved. Unrelated Hematopoietic Stem Cell Donor Matching Probability and Search Algorithm Tue, 13 Nov 2012 08:26:53 +0000 In transplantation of hematopoietic stem cells (HSCs) from unrelated donors a high HLA compatibility level decreases the risk of acute graft-versus-host disease and mortality. The diversity of the HLA system at the allelic and haplotypic level and the heterogeneity of HLA typing data of the registered donors render the search process a complex task. This paper summarizes our experience with a search algorithm that includes at the start of the search a probability estimate (high/intermediate/low) to identify a HLA-A, B, C, DRB1, DQB1-compatible donor (a 10/10 match). Based on 2002–2011 searches about 30% of patients have a high, 30% an intermediate, and 40% a low probability search. Search success rate and duration are presented and discussed in light of the experience of other centers. Overall a 9-10/10 matched HSC donor can now be identified for 60–80% of patients of European descent. For high probability searches donors can be selected on the basis of DPB1-matching with an estimated success rate of >40%. For low probability searches there is no consensus on which HLA incompatibilities are more permissive, although HLA-DQB1 mismatches are generally considered as acceptable. Models for the discrimination of more detrimental mismatches based on specific amino acid residues rather than specific HLA alleles are presented. J.-M. Tiercy Copyright © 2012 J.-M. Tiercy. All rights reserved. Role of Killer Immunoglobulin-Like Receptor and Ligand Matching in Donor Selection Sat, 10 Nov 2012 11:08:35 +0000 Despite all efforts to improve HLA typing and immunosuppression, it is still impossible to prevent severe graft versus host disease (GVHD) which can be fatal. GVHD is not always associated with graft versus malignancy and can prevent stem cell transplantation from reaching its goals. Overall T-cell alloreactivity is not the sole mechanism modulating the immune defense. Innate immune system has its own antigens, ligands, and mediators. The bridge between HLA and natural killer (NK) cell-mediated reactions is becoming better understood in the context of stem cell transplantation. Killer immunoglobulin-like receptors (KIRs) constitute a wide range of alleles/antigens segregated independently from the HLA alleles and classified into two major haplotypes which imprints the person's ability to suppress or to amplify T-cell alloreactivity. This paper will summarize the impact of both activating and inhibitory KIRs and their ligands on stem cell transplantation outcome. The ultimate goal is to develop algorithms based on KIR profiles to select donors with maximum antileukemic and minimum antihost effects. Meral Beksaç and Klara Dalva Copyright © 2012 Meral Beksaç and Klara Dalva. All rights reserved. Occurrence and Impact of Minor Histocompatibility Antigens' Disparities on Outcomes of Hematopoietic Stem Cell Transplantation from HLA-Matched Sibling Donors Thu, 08 Nov 2012 15:27:57 +0000 We have examined the alleles of eleven minor histocompatibility antigens (MiHAs) and investigated the occurrence of immunogenic MiHA disparities in 62 recipients of allogeneic hematopoietic cell transplantation (allo-HCT) with myeloablative conditioning performed between 2000 and 2008 and in their HLA-matched sibling donors. Immunogenic MiHA mismatches were detected in 42 donor-recipient pairs: in 29% MiHA was mismatched in HVG direction, in another 29% in GVH direction; bidirectional MiHA disparity was detected in 10% and no MiHA mismatches in 32%. Patients with GVH-directed HY mismatches had lower both overall survival and disease-free survival at 3 years than patients with compatible HY; also higher incidence of both severe acute GvHD and extensive chronic GVHD was observed in patients with GVH-directed HY mismatch. On contrary, GVH-directed mismatches of autosomally encoded MiHAs had no negative effect on overall survival. Results of our study help to understand why posttransplant courses of allo-HCT from siblings may vary despite the complete high-resolution HLA matching of a donor and a recipient. Monika Dzierzak-Mietla, M. Markiewicz, Urszula Siekiera, Sylwia Mizia, Anna Koclega, Patrycja Zielinska, Malgorzata Sobczyk-Kruszelnicka, and Slawomira Kyrcz-Krzemien Copyright © 2012 Monika Dzierzak-Mietla et al. All rights reserved. Computer Algorithms in the Search for Unrelated Stem Cell Donors Thu, 01 Nov 2012 11:23:17 +0000 Hematopoietic stem cell transplantation (HSCT) is a medical procedure in the field of hematology and oncology, most often performed for patients with certain cancers of the blood or bone marrow. A lot of patients have no suitable HLA-matched donor within their family, so physicians must activate a “donor search process” by interacting with national and international donor registries who will search their databases for adult unrelated donors or cord blood units (CBU). Information and communication technologies play a key role in the donor search process in donor registries both nationally and internationaly. One of the major challenges for donor registry computer systems is the development of a reliable search algorithm. This work discusses the top-down design of such algorithms and current practice. Based on our experience with systems used by several stem cell donor registries, we highlight typical pitfalls in the implementation of an algorithm and underlying data structure. David Steiner Copyright © 2012 David Steiner. All rights reserved. The Presence of Anti-HLA Antibodies before and after Allogeneic Hematopoietic Stem Cells Transplantation from HLA-Mismatched Unrelated Donors Wed, 24 Oct 2012 08:40:21 +0000 Although anti-human leukocyte antigen antibodies (anti-HLA Abs) are important factors responsible for graft rejection in solid organ transplantation and play a role in post-transfusion complications, their role in allogeneic hematopoietic stem cell transplantation (allo-HSCT) has not been finally defined. Enormous polymorphism of HLA-genes, their immunogenicity and heterogeneity of antibodies, as well as the growing number of allo-HSCTs from partially HLA-mismatched donors, increase the probability that anti-HLA antibodies could be important factors responsible for the treatment outcomes. We have examined the incidence of anti-HLA antibodies in a group of 30 allo-HSCT recipients from HLA-mismatched unrelated donors. Anti-HLA Abs were identified in sera collected before and after allo-HSCT. We have used automated DynaChip assay utilizing microchips bearing purified class I and II HLA antigens for detection of anti-HLA Abs. We have detected anit-HLA antibodies against HLA-A, B, C, DR, DQ and DP, but no donor or recipient-specific anti-HLA Abs were detected in the studied group. The preliminary results indicate that anti-HLA antibodies are present before and after allo-HSCT in HLA-mismatched recipients. Anna Koclega, Miroslaw Markiewicz, Urszula Siekiera, Alicja Dobrowolska, Mizia Sylwia, Monika Dzierzak-Mietla, Patrycja Zielinska, Malgorzata Sobczyk Kruszelnicka, Andrzej Lange, and Slawomira Kyrcz-Krzemien Copyright © 2012 Anna Koclega et al. All rights reserved. Both Optimal Matching and Procedure Duration Influence Survival of Patients after Unrelated Donor Hematopoietic Stem Cell Transplantation Mon, 22 Oct 2012 09:08:38 +0000 Eighty-six patients suffering from hematological malignancies, immunodeficiencies, and aplastic anemias received alloHSCT from unrelated donors. Donors were selected from the BMDW files and further matching was performed according to the confirmatory typing procedure with the use of PCR SSP and that based on sequencing. The time from the clinical request of the donor search to the final decision of clinicians accepting the donor was from 0.3 to 17.8 months (median 1.6). Matching was analyzed at the allele level, and 50, 27, and 9 donor-recipient pairs were 10/10 matched, mismatched in one or more alleles, respectively. In an univariate analysis we found better survival if patients were transplanted: (i) from donors matched 10/10 , (ii) not from female donor to male recipient , (iii) in female donation from those with ≤1 pregnancy than multiparous . Notably, it became apparent that duration of the confirmatory typing process affected the survival (HR = 1.138, ). In multivariate analysis only the level of matching and the duration of the matching procedure significantly affected the survival. In conclusion, the duration of the matching procedure in addition to the level of matching should be considered as an independent risk factor of survival. Sylwia Mizia, Dorota Dera-Joachimiak, Malgorzata Polak, Katarzyna Koscinska, Mariola Sedzimirska, and Andrzej Lange Copyright © 2012 Sylwia Mizia et al. All rights reserved. NOD2 Polymorphisms and Their Impact on Haematopoietic Stem Cell Transplant Outcome Thu, 18 Oct 2012 08:17:25 +0000 Haematopoietic stem cell transplantation (HSCT) is a valuable tool in the treatment of many haematological disorders. Advances in understanding HLA matching have improved prognoses. However, many recipients of well-matched HSCT develop posttransplant complications, and survival is far from absolute. The pursuit of novel genetic factors that may impact on HSCT outcome has resulted in the publication of many articles on a multitude of genes. Three NOD2 polymorphisms, identified as disease-associated variants in Crohn’s disease, have recently been suggested as important candidate gene markers in the outcome of HSCT. It was originally postulated that as the clinical manifestation of inflammatory responses characteristic of several post-transplant complications was of notable similarity to those seen in Crohn’s disease, it was possible that they shared a common cause. Since the publication of this first paper, numerous studies have attempted to replicate the results in different transplant settings. The data has varied considerably between studies, and as yet no consensus on the impact of NOD2 SNPs on HSCT outcome has been achieved. Here, we will review the existing literature, summarise current theories as to why the data differs, and suggest possible mechanisms by which the SNPs affect HSCT outcome. Neema P. Mayor, Bronwen E. Shaw, J. Alejandro Madrigal, and Steven G. E. Marsh Copyright © 2012 Neema P. Mayor et al. All rights reserved. Controversies and Recent Advances in Hematopoietic Cell Transplantation for Follicular Non-Hodgkin Lymphoma Thu, 11 Oct 2012 15:52:37 +0000 Commonly designated as an indolent non-Hodgkin lymphoma, follicular lymphoma (FL) presents with striking pathobiological and clinical heterogeneity. Initial management strategies for FL have evolved to involve combination chemoimmunotherapy and/or radio-immunoconjugates. Unfortunately even with the best available nontransplant treatment, which nowadays results in higher frequency of response, FL remains incurable. Although considered a feasible therapeutic option, the use of hematopoietic cell transplantation (HCT) remains controversial. The appropriate timing, graft source, and intensity of HCT conditioning regimens in FL are often matters of debate. Herein we review the available published data pertaining to the use of autologous or allogeneic HCT in patients with FL across different stages of the disease, discuss major recent advances in the field, and highlight avenues for future research. The current literature does not support a role of HCT for FL in first remission, but in the relapsed setting autologous HCT remains appropriate for patients with early chemosensitive relapses, while allogeneic transplantation remains the sole curative modality for this disease, in relatively younger patients without significant comorbidities. Abraham S. Kanate, Mohamed A. Kharfan-Dabaja, and Mehdi Hamadani Copyright © 2012 Abraham S. Kanate et al. All rights reserved. The Role of HLA in Cord Blood Transplantation Thu, 11 Oct 2012 14:57:55 +0000 In recent years, umbilical cord blood (CB), a rich source of hematopoietic stem cells (HSC), has been used successfully as an alternative HSC source to treat a variety of hematologic, immunologic, genetic, and oncologic disorders. CB has several advantages, including prompt availability of the transplant, decrease of graft versus host disease (GVHD) and better long-term immune recovery, resulting in a similar long-term survival. Studies have shown that some degree of HLA mismatches is acceptable. This review is intended to outline the main aspects of HLA matching in different settings (related, pediatric, adult, or double-unit HSCT), its effect on transplantation outcome and the role of HLA in donor selection. Catherine Stavropoulos-Giokas, Amalia Dinou, and Andreas Papassavas Copyright © 2012 Catherine Stavropoulos-Giokas et al. All rights reserved. Th17 Mediated Alloreactivity Is Facilitated by the Pre-Transplant Microbial Burden of the Recipient Tue, 09 Oct 2012 08:15:23 +0000 Acute graft-versus-host disease (aGvHD) is a major complication after hematopoietic stem cell transplantation (HSCT) and severity of aGvHD is associated with biological and genetic factors related to donors and recipients. Studies on inflammatory pathways involved in aGvHD have shown a significant impact of the gut microflora on aGvHD development giving increasing evidence in the understanding of the response of innate and adaptive immunity to microbial products. Cytokine deregulation may increase or reduce the risk of aGvHD. Damage of tissues affected by aGvHD reflects the immunological cascade of events in this disease. Aleksandra Klimczak and Andrzej Lange Copyright © 2012 Aleksandra Klimczak and Andrzej Lange. All rights reserved. Inhibition of Mammalian Target of Rapamycin in Human Acute Myeloid Leukemia Cells Has Diverse Effects That Depend on the Environmental In Vitro Stress Tue, 02 Oct 2012 12:16:42 +0000 Effects of the mTOR inhibitor rapamycin were characterized on in vitro cultured primary human acute myeloid leukemia (AML) cells and five AML cell lines. Constitutive mTOR activation seemed to be a general characteristic of primary AML cells. Increased cellular stress induced by serum deprivation increased both mTOR signaling, lysosomal acidity, and in vitro apoptosis, where lysosomal acidity/apoptosis were independent of increased mTOR signaling. Rapamycin had antiproliferative and proapoptotic effects only for a subset of patients. Proapoptotic effect was detected for AML cell lines only in the presence of serum. Combination of rapamycin with valproic acid, all-trans retinoic acid (ATRA), and NF-κB inhibitors showed no interference with constitutive mTOR activation and mTOR inhibitory effect of rapamycin and no additional proapoptotic effect compared to rapamycin alone. In contrast, dual inhibition of the PI3K-Akt-mTOR pathway by rapamycin plus a PI3K inhibitor induced new functional effects that did not simply reflect a summary of single drug effects. To conclude, (i) pharmacological characterization of PI3K-Akt-mTOR inhibitors requires carefully standardized experimental models, (ii) rapamycin effects differ between patients, and (iii) combined targeting of different steps in this pathway should be further investigated whereas combination of rapamycin with valproic acid, ATRA, or NF-κB inhibitors seems less promising. Anita Ryningen, Håkon Reikvam, Ina Nepstad, Kristin Paulsen Rye, and Øystein Bruserud Copyright © 2012 Anita Ryningen et al. All rights reserved. Role of HLA in Hematopoietic Stem Cell Transplantation Tue, 02 Oct 2012 11:43:05 +0000 The selection of hematopoietic stem cell transplantation (HSCT) donors includes a rigorous assessment of the availability and human leukocyte antigen (HLA) match status of donors. HLA plays a critical role in HSCT, but its involvement in HSCT is constantly in flux because of changing technologies and variations in clinical transplantation results. The increased availability of HSCT through the use of HLA-mismatched related and unrelated donors is feasible with a more complete understanding of permissible HLA mismatches and the role of killer-cell immunoglobulin-like receptor (KIR) genes in HSCT. The influence of nongenetic factors on the tolerability of HLA mismatching has recently become evident, demonstrating a need for the integration of both genetic and nongenetic variables in donor selection. Meerim Park and Jong Jin Seo Copyright © 2012 Meerim Park and Jong Jin Seo. All rights reserved.